| \input texinfo @c -*-texinfo-*- |
| |
| @c %**start of header |
| @setfilename libgomp.info |
| @settitle GNU libgomp |
| @c %**end of header |
| |
| |
| @copying |
| Copyright @copyright{} 2006-2023 Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with the |
| Invariant Sections being ``Funding Free Software'', the Front-Cover |
| texts being (a) (see below), and with the Back-Cover Texts being (b) |
| (see below). A copy of the license is included in the section entitled |
| ``GNU Free Documentation License''. |
| |
| (a) The FSF's Front-Cover Text is: |
| |
| A GNU Manual |
| |
| (b) The FSF's Back-Cover Text is: |
| |
| You have freedom to copy and modify this GNU Manual, like GNU |
| software. Copies published by the Free Software Foundation raise |
| funds for GNU development. |
| @end copying |
| |
| @ifinfo |
| @dircategory GNU Libraries |
| @direntry |
| * libgomp: (libgomp). GNU Offloading and Multi Processing Runtime Library. |
| @end direntry |
| |
| This manual documents libgomp, the GNU Offloading and Multi Processing |
| Runtime library. This is the GNU implementation of the OpenMP and |
| OpenACC APIs for parallel and accelerator programming in C/C++ and |
| Fortran. |
| |
| Published by the Free Software Foundation |
| 51 Franklin Street, Fifth Floor |
| Boston, MA 02110-1301 USA |
| |
| @insertcopying |
| @end ifinfo |
| |
| |
| @setchapternewpage odd |
| |
| @titlepage |
| @title GNU Offloading and Multi Processing Runtime Library |
| @subtitle The GNU OpenMP and OpenACC Implementation |
| @page |
| @vskip 0pt plus 1filll |
| @comment For the @value{version-GCC} Version* |
| @sp 1 |
| Published by the Free Software Foundation @* |
| 51 Franklin Street, Fifth Floor@* |
| Boston, MA 02110-1301, USA@* |
| @sp 1 |
| @insertcopying |
| @end titlepage |
| |
| @summarycontents |
| @contents |
| @page |
| |
| |
| @node Top, Enabling OpenMP |
| @top Introduction |
| @cindex Introduction |
| |
| This manual documents the usage of libgomp, the GNU Offloading and |
| Multi Processing Runtime Library. This includes the GNU |
| implementation of the @uref{https://www.openmp.org, OpenMP} Application |
| Programming Interface (API) for multi-platform shared-memory parallel |
| programming in C/C++ and Fortran, and the GNU implementation of the |
| @uref{https://www.openacc.org, OpenACC} Application Programming |
| Interface (API) for offloading of code to accelerator devices in C/C++ |
| and Fortran. |
| |
| Originally, libgomp implemented the GNU OpenMP Runtime Library. Based |
| on this, support for OpenACC and offloading (both OpenACC and OpenMP |
| 4's target construct) has been added later on, and the library's name |
| changed to GNU Offloading and Multi Processing Runtime Library. |
| |
| |
| |
| @comment |
| @comment When you add a new menu item, please keep the right hand |
| @comment aligned to the same column. Do not use tabs. This provides |
| @comment better formatting. |
| @comment |
| @menu |
| * Enabling OpenMP:: How to enable OpenMP for your applications. |
| * OpenMP Implementation Status:: List of implemented features by OpenMP version |
| * OpenMP Runtime Library Routines: Runtime Library Routines. |
| The OpenMP runtime application programming |
| interface. |
| * OpenMP Environment Variables: Environment Variables. |
| Influencing OpenMP runtime behavior with |
| environment variables. |
| * Enabling OpenACC:: How to enable OpenACC for your |
| applications. |
| * OpenACC Runtime Library Routines:: The OpenACC runtime application |
| programming interface. |
| * OpenACC Environment Variables:: Influencing OpenACC runtime behavior with |
| environment variables. |
| * CUDA Streams Usage:: Notes on the implementation of |
| asynchronous operations. |
| * OpenACC Library Interoperability:: OpenACC library interoperability with the |
| NVIDIA CUBLAS library. |
| * OpenACC Profiling Interface:: |
| * OpenMP-Implementation Specifics:: Notes specifics of this OpenMP |
| implementation |
| * Offload-Target Specifics:: Notes on offload-target specific internals |
| * The libgomp ABI:: Notes on the external ABI presented by libgomp. |
| * Reporting Bugs:: How to report bugs in the GNU Offloading and |
| Multi Processing Runtime Library. |
| * Copying:: GNU general public license says |
| how you can copy and share libgomp. |
| * GNU Free Documentation License:: |
| How you can copy and share this manual. |
| * Funding:: How to help assure continued work for free |
| software. |
| * Library Index:: Index of this documentation. |
| @end menu |
| |
| |
| @c --------------------------------------------------------------------- |
| @c Enabling OpenMP |
| @c --------------------------------------------------------------------- |
| |
| @node Enabling OpenMP |
| @chapter Enabling OpenMP |
| |
| To activate the OpenMP extensions for C/C++ and Fortran, the compile-time |
| flag @option{-fopenmp} must be specified. For C and C++, this enables |
| the handling of the OpenMP directives using @code{#pragma omp} and the |
| @code{[[omp::directive(...)]]}, @code{[[omp::sequence(...)]]} and |
| @code{[[omp::decl(...)]]} attributes. For Fortran, it enables for |
| free source form the @code{!$omp} sentinel for directives and the |
| @code{!$} conditional compilation sentinel and for fixed source form the |
| @code{c$omp}, @code{*$omp} and @code{!$omp} sentinels for directives and |
| the @code{c$}, @code{*$} and @code{!$} conditional compilation sentinels. |
| The flag also arranges for automatic linking of the OpenMP runtime library |
| (@ref{Runtime Library Routines}). |
| |
| The @option{-fopenmp-simd} flag can be used to enable a subset of |
| OpenMP directives that do not require the linking of either the |
| OpenMP runtime library or the POSIX threads library. |
| |
| A complete description of all OpenMP directives may be found in the |
| @uref{https://www.openmp.org, OpenMP Application Program Interface} manuals. |
| See also @ref{OpenMP Implementation Status}. |
| |
| |
| @c --------------------------------------------------------------------- |
| @c OpenMP Implementation Status |
| @c --------------------------------------------------------------------- |
| |
| @node OpenMP Implementation Status |
| @chapter OpenMP Implementation Status |
| |
| @menu |
| * OpenMP 4.5:: Feature completion status to 4.5 specification |
| * OpenMP 5.0:: Feature completion status to 5.0 specification |
| * OpenMP 5.1:: Feature completion status to 5.1 specification |
| * OpenMP 5.2:: Feature completion status to 5.2 specification |
| * OpenMP Technical Report 12:: Feature completion status to second 6.0 preview |
| @end menu |
| |
| The @code{_OPENMP} preprocessor macro and Fortran's @code{openmp_version} |
| parameter, provided by @code{omp_lib.h} and the @code{omp_lib} module, have |
| the value @code{201511} (i.e. OpenMP 4.5). |
| |
| @node OpenMP 4.5 |
| @section OpenMP 4.5 |
| |
| The OpenMP 4.5 specification is fully supported. |
| |
| @node OpenMP 5.0 |
| @section OpenMP 5.0 |
| |
| @unnumberedsubsec New features listed in Appendix B of the OpenMP specification |
| @c This list is sorted as in OpenMP 5.1's B.3 not as in OpenMP 5.0's B.2 |
| |
| @multitable @columnfractions .60 .10 .25 |
| @headitem Description @tab Status @tab Comments |
| @item Array shaping @tab N @tab |
| @item Array sections with non-unit strides in C and C++ @tab N @tab |
| @item Iterators @tab Y @tab |
| @item @code{metadirective} directive @tab N @tab |
| @item @code{declare variant} directive |
| @tab P @tab @emph{simd} traits not handled correctly |
| @item @var{target-offload-var} ICV and @code{OMP_TARGET_OFFLOAD} |
| env variable @tab Y @tab |
| @item Nested-parallel changes to @var{max-active-levels-var} ICV @tab Y @tab |
| @item @code{requires} directive @tab P |
| @tab complete but no non-host device provides @code{unified_shared_memory} |
| @item @code{teams} construct outside an enclosing target region @tab Y @tab |
| @item Non-rectangular loop nests @tab P |
| @tab Full support for C/C++, partial for Fortran |
| (@uref{https://gcc.gnu.org/PR110735,PR110735}) |
| @item @code{!=} as relational-op in canonical loop form for C/C++ @tab Y @tab |
| @item @code{nonmonotonic} as default loop schedule modifier for worksharing-loop |
| constructs @tab Y @tab |
| @item Collapse of associated loops that are imperfectly nested loops @tab Y @tab |
| @item Clauses @code{if}, @code{nontemporal} and @code{order(concurrent)} in |
| @code{simd} construct @tab Y @tab |
| @item @code{atomic} constructs in @code{simd} @tab Y @tab |
| @item @code{loop} construct @tab Y @tab |
| @item @code{order(concurrent)} clause @tab Y @tab |
| @item @code{scan} directive and @code{in_scan} modifier for the |
| @code{reduction} clause @tab Y @tab |
| @item @code{in_reduction} clause on @code{task} constructs @tab Y @tab |
| @item @code{in_reduction} clause on @code{target} constructs @tab P |
| @tab @code{nowait} only stub |
| @item @code{task_reduction} clause with @code{taskgroup} @tab Y @tab |
| @item @code{task} modifier to @code{reduction} clause @tab Y @tab |
| @item @code{affinity} clause to @code{task} construct @tab Y @tab Stub only |
| @item @code{detach} clause to @code{task} construct @tab Y @tab |
| @item @code{omp_fulfill_event} runtime routine @tab Y @tab |
| @item @code{reduction} and @code{in_reduction} clauses on @code{taskloop} |
| and @code{taskloop simd} constructs @tab Y @tab |
| @item @code{taskloop} construct cancelable by @code{cancel} construct |
| @tab Y @tab |
| @item @code{mutexinoutset} @emph{dependence-type} for @code{depend} clause |
| @tab Y @tab |
| @item Predefined memory spaces, memory allocators, allocator traits |
| @tab Y @tab See also @ref{Memory allocation} |
| @item Memory management routines @tab Y @tab |
| @item @code{allocate} directive @tab P @tab Only C and Fortran, only stack variables |
| @item @code{allocate} clause @tab P @tab Initial support |
| @item @code{use_device_addr} clause on @code{target data} @tab Y @tab |
| @item @code{ancestor} modifier on @code{device} clause @tab Y @tab |
| @item Implicit declare target directive @tab Y @tab |
| @item Discontiguous array section with @code{target update} construct |
| @tab N @tab |
| @item C/C++'s lvalue expressions in @code{to}, @code{from} |
| and @code{map} clauses @tab N @tab |
| @item C/C++'s lvalue expressions in @code{depend} clauses @tab Y @tab |
| @item Nested @code{declare target} directive @tab Y @tab |
| @item Combined @code{master} constructs @tab Y @tab |
| @item @code{depend} clause on @code{taskwait} @tab Y @tab |
| @item Weak memory ordering clauses on @code{atomic} and @code{flush} construct |
| @tab Y @tab |
| @item @code{hint} clause on the @code{atomic} construct @tab Y @tab Stub only |
| @item @code{depobj} construct and depend objects @tab Y @tab |
| @item Lock hints were renamed to synchronization hints @tab Y @tab |
| @item @code{conditional} modifier to @code{lastprivate} clause @tab Y @tab |
| @item Map-order clarifications @tab P @tab |
| @item @code{close} @emph{map-type-modifier} @tab Y @tab |
| @item Mapping C/C++ pointer variables and to assign the address of |
| device memory mapped by an array section @tab P @tab |
| @item Mapping of Fortran pointer and allocatable variables, including pointer |
| and allocatable components of variables |
| @tab P @tab Mapping of vars with allocatable components unsupported |
| @item @code{defaultmap} extensions @tab Y @tab |
| @item @code{declare mapper} directive @tab N @tab |
| @item @code{omp_get_supported_active_levels} routine @tab Y @tab |
| @item Runtime routines and environment variables to display runtime thread |
| affinity information @tab Y @tab |
| @item @code{omp_pause_resource} and @code{omp_pause_resource_all} runtime |
| routines @tab Y @tab |
| @item @code{omp_get_device_num} runtime routine @tab Y @tab |
| @item OMPT interface @tab N @tab |
| @item OMPD interface @tab N @tab |
| @end multitable |
| |
| @unnumberedsubsec Other new OpenMP 5.0 features |
| |
| @multitable @columnfractions .60 .10 .25 |
| @headitem Description @tab Status @tab Comments |
| @item Supporting C++'s range-based for loop @tab Y @tab |
| @end multitable |
| |
| |
| @node OpenMP 5.1 |
| @section OpenMP 5.1 |
| |
| @unnumberedsubsec New features listed in Appendix B of the OpenMP specification |
| |
| @multitable @columnfractions .60 .10 .25 |
| @headitem Description @tab Status @tab Comments |
| @item OpenMP directive as C++ attribute specifiers @tab Y @tab |
| @item @code{omp_all_memory} reserved locator @tab Y @tab |
| @item @emph{target_device trait} in OpenMP Context @tab N @tab |
| @item @code{target_device} selector set in context selectors @tab N @tab |
| @item C/C++'s @code{declare variant} directive: elision support of |
| preprocessed code @tab N @tab |
| @item @code{declare variant}: new clauses @code{adjust_args} and |
| @code{append_args} @tab N @tab |
| @item @code{dispatch} construct @tab N @tab |
| @item device-specific ICV settings with environment variables @tab Y @tab |
| @item @code{assume} and @code{assumes} directives @tab Y @tab |
| @item @code{nothing} directive @tab Y @tab |
| @item @code{error} directive @tab Y @tab |
| @item @code{masked} construct @tab Y @tab |
| @item @code{scope} directive @tab Y @tab |
| @item Loop transformation constructs @tab N @tab |
| @item @code{strict} modifier in the @code{grainsize} and @code{num_tasks} |
| clauses of the @code{taskloop} construct @tab Y @tab |
| @item @code{align} clause in @code{allocate} directive @tab P |
| @tab Only C and Fortran (and only stack variables) |
| @item @code{align} modifier in @code{allocate} clause @tab Y @tab |
| @item @code{thread_limit} clause to @code{target} construct @tab Y @tab |
| @item @code{has_device_addr} clause to @code{target} construct @tab Y @tab |
| @item Iterators in @code{target update} motion clauses and @code{map} |
| clauses @tab N @tab |
| @item Indirect calls to the device version of a procedure or function in |
| @code{target} regions @tab P @tab Only C and C++ |
| @item @code{interop} directive @tab N @tab |
| @item @code{omp_interop_t} object support in runtime routines @tab N @tab |
| @item @code{nowait} clause in @code{taskwait} directive @tab Y @tab |
| @item Extensions to the @code{atomic} directive @tab Y @tab |
| @item @code{seq_cst} clause on a @code{flush} construct @tab Y @tab |
| @item @code{inoutset} argument to the @code{depend} clause @tab Y @tab |
| @item @code{private} and @code{firstprivate} argument to @code{default} |
| clause in C and C++ @tab Y @tab |
| @item @code{present} argument to @code{defaultmap} clause @tab Y @tab |
| @item @code{omp_set_num_teams}, @code{omp_set_teams_thread_limit}, |
| @code{omp_get_max_teams}, @code{omp_get_teams_thread_limit} runtime |
| routines @tab Y @tab |
| @item @code{omp_target_is_accessible} runtime routine @tab Y @tab |
| @item @code{omp_target_memcpy_async} and @code{omp_target_memcpy_rect_async} |
| runtime routines @tab Y @tab |
| @item @code{omp_get_mapped_ptr} runtime routine @tab Y @tab |
| @item @code{omp_calloc}, @code{omp_realloc}, @code{omp_aligned_alloc} and |
| @code{omp_aligned_calloc} runtime routines @tab Y @tab |
| @item @code{omp_alloctrait_key_t} enum: @code{omp_atv_serialized} added, |
| @code{omp_atv_default} changed @tab Y @tab |
| @item @code{omp_display_env} runtime routine @tab Y @tab |
| @item @code{ompt_scope_endpoint_t} enum: @code{ompt_scope_beginend} @tab N @tab |
| @item @code{ompt_sync_region_t} enum additions @tab N @tab |
| @item @code{ompt_state_t} enum: @code{ompt_state_wait_barrier_implementation} |
| and @code{ompt_state_wait_barrier_teams} @tab N @tab |
| @item @code{ompt_callback_target_data_op_emi_t}, |
| @code{ompt_callback_target_emi_t}, @code{ompt_callback_target_map_emi_t} |
| and @code{ompt_callback_target_submit_emi_t} @tab N @tab |
| @item @code{ompt_callback_error_t} type @tab N @tab |
| @item @code{OMP_PLACES} syntax extensions @tab Y @tab |
| @item @code{OMP_NUM_TEAMS} and @code{OMP_TEAMS_THREAD_LIMIT} environment |
| variables @tab Y @tab |
| @end multitable |
| |
| @unnumberedsubsec Other new OpenMP 5.1 features |
| |
| @multitable @columnfractions .60 .10 .25 |
| @headitem Description @tab Status @tab Comments |
| @item Support of strictly structured blocks in Fortran @tab Y @tab |
| @item Support of structured block sequences in C/C++ @tab Y @tab |
| @item @code{unconstrained} and @code{reproducible} modifiers on @code{order} |
| clause @tab Y @tab |
| @item Support @code{begin/end declare target} syntax in C/C++ @tab Y @tab |
| @item Pointer predetermined firstprivate getting initialized |
| to address of matching mapped list item per 5.1, Sect. 2.21.7.2 @tab N @tab |
| @item For Fortran, diagnose placing declarative before/between @code{USE}, |
| @code{IMPORT}, and @code{IMPLICIT} as invalid @tab N @tab |
| @item Optional comma between directive and clause in the @code{#pragma} form @tab Y @tab |
| @item @code{indirect} clause in @code{declare target} @tab P @tab Only C and C++ |
| @item @code{device_type(nohost)}/@code{device_type(host)} for variables @tab N @tab |
| @item @code{present} modifier to the @code{map}, @code{to} and @code{from} |
| clauses @tab Y @tab |
| @end multitable |
| |
| |
| @node OpenMP 5.2 |
| @section OpenMP 5.2 |
| |
| @unnumberedsubsec New features listed in Appendix B of the OpenMP specification |
| |
| @multitable @columnfractions .60 .10 .25 |
| @headitem Description @tab Status @tab Comments |
| @item @code{omp_in_explicit_task} routine and @var{explicit-task-var} ICV |
| @tab Y @tab |
| @item @code{omp}/@code{ompx}/@code{omx} sentinels and @code{omp_}/@code{ompx_} |
| namespaces @tab N/A |
| @tab warning for @code{ompx/omx} sentinels@footnote{The @code{ompx} |
| sentinel as C/C++ pragma and C++ attributes are warned for with |
| @code{-Wunknown-pragmas} (implied by @code{-Wall}) and @code{-Wattributes} |
| (enabled by default), respectively; for Fortran free-source code, there is |
| a warning enabled by default and, for fixed-source code, the @code{omx} |
| sentinel is warned for with with @code{-Wsurprising} (enabled by |
| @code{-Wall}). Unknown clauses are always rejected with an error.} |
| @item Clauses on @code{end} directive can be on directive @tab Y @tab |
| @item @code{destroy} clause with destroy-var argument on @code{depobj} |
| @tab Y @tab |
| @item Deprecation of no-argument @code{destroy} clause on @code{depobj} |
| @tab N @tab |
| @item @code{linear} clause syntax changes and @code{step} modifier @tab Y @tab |
| @item Deprecation of minus operator for reductions @tab N @tab |
| @item Deprecation of separating @code{map} modifiers without comma @tab N @tab |
| @item @code{declare mapper} with iterator and @code{present} modifiers |
| @tab N @tab |
| @item If a matching mapped list item is not found in the data environment, the |
| pointer retains its original value @tab Y @tab |
| @item New @code{enter} clause as alias for @code{to} on declare target directive |
| @tab Y @tab |
| @item Deprecation of @code{to} clause on declare target directive @tab N @tab |
| @item Extended list of directives permitted in Fortran pure procedures |
| @tab Y @tab |
| @item New @code{allocators} directive for Fortran @tab N @tab |
| @item Deprecation of @code{allocate} directive for Fortran |
| allocatables/pointers @tab N @tab |
| @item Optional paired @code{end} directive with @code{dispatch} @tab N @tab |
| @item New @code{memspace} and @code{traits} modifiers for @code{uses_allocators} |
| @tab N @tab |
| @item Deprecation of traits array following the allocator_handle expression in |
| @code{uses_allocators} @tab N @tab |
| @item New @code{otherwise} clause as alias for @code{default} on metadirectives |
| @tab N @tab |
| @item Deprecation of @code{default} clause on metadirectives @tab N @tab |
| @item Deprecation of delimited form of @code{declare target} @tab N @tab |
| @item Reproducible semantics changed for @code{order(concurrent)} @tab N @tab |
| @item @code{allocate} and @code{firstprivate} clauses on @code{scope} |
| @tab Y @tab |
| @item @code{ompt_callback_work} @tab N @tab |
| @item Default map-type for the @code{map} clause in @code{target enter/exit data} |
| @tab Y @tab |
| @item New @code{doacross} clause as alias for @code{depend} with |
| @code{source}/@code{sink} modifier @tab Y @tab |
| @item Deprecation of @code{depend} with @code{source}/@code{sink} modifier |
| @tab N @tab |
| @item @code{omp_cur_iteration} keyword @tab Y @tab |
| @end multitable |
| |
| @unnumberedsubsec Other new OpenMP 5.2 features |
| |
| @multitable @columnfractions .60 .10 .25 |
| @headitem Description @tab Status @tab Comments |
| @item For Fortran, optional comma between directive and clause @tab N @tab |
| @item Conforming device numbers and @code{omp_initial_device} and |
| @code{omp_invalid_device} enum/PARAMETER @tab Y @tab |
| @item Initial value of @var{default-device-var} ICV with |
| @code{OMP_TARGET_OFFLOAD=mandatory} @tab Y @tab |
| @item @code{all} as @emph{implicit-behavior} for @code{defaultmap} @tab Y @tab |
| @item @emph{interop_types} in any position of the modifier list for the @code{init} clause |
| of the @code{interop} construct @tab N @tab |
| @item Invoke virtual member functions of C++ objects created on the host device |
| on other devices @tab N @tab |
| @end multitable |
| |
| |
| @node OpenMP Technical Report 12 |
| @section OpenMP Technical Report 12 |
| |
| Technical Report (TR) 12 is the second preview for OpenMP 6.0. |
| |
| @unnumberedsubsec New features listed in Appendix B of the OpenMP specification |
| @multitable @columnfractions .60 .10 .25 |
| @item Features deprecated in versions 5.2, 5.1 and 5.0 were removed |
| @tab N/A @tab Backward compatibility |
| @item Full support for C23 was added @tab P @tab |
| @item Full support for C++23 was added @tab P @tab |
| @item @code{_ALL} suffix to the device-scope environment variables |
| @tab P @tab Host device number wrongly accepted |
| @item @code{num_threads} now accepts a list @tab N @tab |
| @item Supporting increments with abstract names in @code{OMP_PLACES} @tab N @tab |
| @item Extension of @code{OMP_DEFAULT_DEVICE} and new |
| @code{OMP_AVAILABLE_DEVICES} environment vars @tab N @tab |
| @item New @code{OMP_THREADS_RESERVE} environment variable @tab N @tab |
| @item The @code{decl} attribute was added to the C++ attribute syntax |
| @tab Y @tab |
| @item The OpenMP directive syntax was extended to include C 23 attribute |
| specifiers @tab Y @tab |
| @item All inarguable clauses take now an optional Boolean argument @tab N @tab |
| @item For Fortran, @emph{locator list} can be also function reference with |
| data pointer result @tab N @tab |
| @item Concept of @emph{assumed-size arrays} in C and C++ |
| @tab N @tab |
| @item @emph{directive-name-modifier} accepted in all clauses @tab N @tab |
| @item For Fortran, atomic with BLOCK construct and, for C/C++, with |
| unlimited curly braces supported @tab N @tab |
| @item For Fortran, atomic compare with storing the comparison result |
| @tab N @tab |
| @item New @code{looprange} clause @tab N @tab |
| @item Ref-count change for @code{use_device_ptr}/@code{use_device_addr} |
| @tab N @tab |
| @item Support for inductions @tab N @tab |
| @item Implicit reduction identifiers of C++ classes |
| @tab N @tab |
| @item Change of the @emph{map-type} property from @emph{ultimate} to |
| @emph{default} @tab N @tab |
| @item @code{self} modifier to @code{map} and @code{self} as |
| @code{defaultmap} argument @tab N @tab |
| @item Mapping of @emph{assumed-size arrays} in C, C++ and Fortran |
| @tab N @tab |
| @item @code{groupprivate} directive @tab N @tab |
| @item @code{local} clause to @code{declare target} directive @tab N @tab |
| @item @code{part_size} allocator trait @tab N @tab |
| @item @code{pin_device}, @code{preferred_device} and @code{target_access} |
| allocator traits |
| @tab N @tab |
| @item @code{access} allocator trait changes @tab N @tab |
| @item Extension of @code{interop} operation of @code{append_args}, allowing all |
| modifiers of the @code{init} clause |
| @tab N @tab |
| @item @code{interop} clause to @code{dispatch} @tab N @tab |
| @item @code{message} and @code{severity} calauses to @code{parallel} directive |
| @tab N @tab |
| @item @code{self} clause to @code{requires} directive @tab N @tab |
| @item @code{no_openmp_constructs} assumptions clause @tab N @tab |
| @item @code{reverse} loop-transformation construct @tab N @tab |
| @item @code{interchange} loop-transformation construct @tab N @tab |
| @item @code{fuse} loop-transformation construct @tab N @tab |
| @item @code{apply} code to loop-transforming constructs @tab N @tab |
| @item @code{omp_curr_progress_width} identifier @tab N @tab |
| @item @code{safesync} clause to the @code{parallel} construct @tab N @tab |
| @item @code{omp_get_max_progress_width} runtime routine @tab N @tab |
| @item @code{strict} modifier keyword to @code{num_threads} @tab N @tab |
| @item @code{atomic} permitted in a construct with @code{order(concurrent)} |
| @tab N @tab |
| @item @code{coexecute} directive for Fortran @tab N @tab |
| @item Fortran DO CONCURRENT as associated loop in a @code{loop} construct |
| @tab N @tab |
| @item @code{threadset} clause in task-generating constructs @tab N @tab |
| @item @code{nowait} clause with reverse-offload @code{target} directives |
| @tab N @tab |
| @item Boolean argument to @code{nowait} and @code{nogroup} may be non constant |
| @tab N @tab |
| @item @code{memscope} clause to @code{atomic} and @code{flush} @tab N @tab |
| @item @code{omp_is_free_agent} and @code{omp_ancestor_is_free_agent} routines |
| @tab N @tab |
| @item @code{omp_target_memset} and @code{omp_target_memset_rect_async} routines |
| @tab N @tab |
| @item Routines for obtaining memory spaces/allocators for shared/device memory |
| @tab N @tab |
| @item @code{omp_get_memspace_num_resources} routine @tab N @tab |
| @item @code{omp_get_submemspace} routine @tab N @tab |
| @item @code{ompt_target_data_transfer} and @code{ompt_target_data_transfer_async} |
| values in @code{ompt_target_data_op_t} enum @tab N @tab |
| @item @code{ompt_get_buffer_limits} OMPT routine @tab N @tab |
| @end multitable |
| |
| @unnumberedsubsec Other new TR 12 features |
| @multitable @columnfractions .60 .10 .25 |
| @item Relaxed Fortran restrictions to the @code{aligned} clause @tab N @tab |
| @item Mapping lambda captures @tab N @tab |
| @item New @code{omp_pause_stop_tool} constant for omp_pause_resource @tab N @tab |
| @end multitable |
| |
| |
| |
| @c --------------------------------------------------------------------- |
| @c OpenMP Runtime Library Routines |
| @c --------------------------------------------------------------------- |
| |
| @node Runtime Library Routines |
| @chapter OpenMP Runtime Library Routines |
| |
| The runtime routines described here are defined by Section 18 of the OpenMP |
| specification in version 5.2. |
| |
| @menu |
| * Thread Team Routines:: |
| * Thread Affinity Routines:: |
| * Teams Region Routines:: |
| * Tasking Routines:: |
| @c * Resource Relinquishing Routines:: |
| * Device Information Routines:: |
| * Device Memory Routines:: |
| * Lock Routines:: |
| * Timing Routines:: |
| * Event Routine:: |
| @c * Interoperability Routines:: |
| * Memory Management Routines:: |
| @c * Tool Control Routine:: |
| @c * Environment Display Routine:: |
| @end menu |
| |
| |
| |
| @node Thread Team Routines |
| @section Thread Team Routines |
| |
| Routines controlling threads in the current contention group. |
| They have C linkage and do not throw exceptions. |
| |
| @menu |
| * omp_set_num_threads:: Set upper team size limit |
| * omp_get_num_threads:: Size of the active team |
| * omp_get_max_threads:: Maximum number of threads of parallel region |
| * omp_get_thread_num:: Current thread ID |
| * omp_in_parallel:: Whether a parallel region is active |
| * omp_set_dynamic:: Enable/disable dynamic teams |
| * omp_get_dynamic:: Dynamic teams setting |
| * omp_get_cancellation:: Whether cancellation support is enabled |
| * omp_set_nested:: Enable/disable nested parallel regions |
| * omp_get_nested:: Nested parallel regions |
| * omp_set_schedule:: Set the runtime scheduling method |
| * omp_get_schedule:: Obtain the runtime scheduling method |
| * omp_get_teams_thread_limit:: Maximum number of threads imposed by teams |
| * omp_get_supported_active_levels:: Maximum number of active regions supported |
| * omp_set_max_active_levels:: Limits the number of active parallel regions |
| * omp_get_max_active_levels:: Current maximum number of active regions |
| * omp_get_level:: Number of parallel regions |
| * omp_get_ancestor_thread_num:: Ancestor thread ID |
| * omp_get_team_size:: Number of threads in a team |
| * omp_get_active_level:: Number of active parallel regions |
| @end menu |
| |
| |
| |
| @node omp_set_num_threads |
| @subsection @code{omp_set_num_threads} -- Set upper team size limit |
| @table @asis |
| @item @emph{Description}: |
| Specifies the number of threads used by default in subsequent parallel |
| sections, if those do not specify a @code{num_threads} clause. The |
| argument of @code{omp_set_num_threads} shall be a positive integer. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_num_threads(int num_threads);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_num_threads(num_threads)} |
| @item @tab @code{integer, intent(in) :: num_threads} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_NUM_THREADS}, @ref{omp_get_num_threads}, @ref{omp_get_max_threads} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.1. |
| @end table |
| |
| |
| |
| @node omp_get_num_threads |
| @subsection @code{omp_get_num_threads} -- Size of the active team |
| @table @asis |
| @item @emph{Description}: |
| Returns the number of threads in the current team. In a sequential section of |
| the program @code{omp_get_num_threads} returns 1. |
| |
| The default team size may be initialized at startup by the |
| @env{OMP_NUM_THREADS} environment variable. At runtime, the size |
| of the current team may be set either by the @code{NUM_THREADS} |
| clause or by @code{omp_set_num_threads}. If none of the above were |
| used to define a specific value and @env{OMP_DYNAMIC} is disabled, |
| one thread per CPU online is used. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_num_threads(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_num_threads()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_max_threads}, @ref{omp_set_num_threads}, @ref{OMP_NUM_THREADS} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.2. |
| @end table |
| |
| |
| |
| @node omp_get_max_threads |
| @subsection @code{omp_get_max_threads} -- Maximum number of threads of parallel region |
| @table @asis |
| @item @emph{Description}: |
| Return the maximum number of threads used for the current parallel region |
| that does not use the clause @code{num_threads}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_max_threads(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_max_threads()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_set_num_threads}, @ref{omp_set_dynamic}, @ref{omp_get_thread_limit} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.3. |
| @end table |
| |
| |
| |
| @node omp_get_thread_num |
| @subsection @code{omp_get_thread_num} -- Current thread ID |
| @table @asis |
| @item @emph{Description}: |
| Returns a unique thread identification number within the current team. |
| In a sequential parts of the program, @code{omp_get_thread_num} |
| always returns 0. In parallel regions the return value varies |
| from 0 to @code{omp_get_num_threads}-1 inclusive. The return |
| value of the primary thread of a team is always 0. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_thread_num(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_thread_num()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_num_threads}, @ref{omp_get_ancestor_thread_num} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.4. |
| @end table |
| |
| |
| |
| @node omp_in_parallel |
| @subsection @code{omp_in_parallel} -- Whether a parallel region is active |
| @table @asis |
| @item @emph{Description}: |
| This function returns @code{true} if currently running in parallel, |
| @code{false} otherwise. Here, @code{true} and @code{false} represent |
| their language-specific counterparts. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_in_parallel(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{logical function omp_in_parallel()} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.6. |
| @end table |
| |
| |
| @node omp_set_dynamic |
| @subsection @code{omp_set_dynamic} -- Enable/disable dynamic teams |
| @table @asis |
| @item @emph{Description}: |
| Enable or disable the dynamic adjustment of the number of threads |
| within a team. The function takes the language-specific equivalent |
| of @code{true} and @code{false}, where @code{true} enables dynamic |
| adjustment of team sizes and @code{false} disables it. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_dynamic(int dynamic_threads);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_dynamic(dynamic_threads)} |
| @item @tab @code{logical, intent(in) :: dynamic_threads} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_DYNAMIC}, @ref{omp_get_dynamic} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.7. |
| @end table |
| |
| |
| |
| @node omp_get_dynamic |
| @subsection @code{omp_get_dynamic} -- Dynamic teams setting |
| @table @asis |
| @item @emph{Description}: |
| This function returns @code{true} if enabled, @code{false} otherwise. |
| Here, @code{true} and @code{false} represent their language-specific |
| counterparts. |
| |
| The dynamic team setting may be initialized at startup by the |
| @env{OMP_DYNAMIC} environment variable or at runtime using |
| @code{omp_set_dynamic}. If undefined, dynamic adjustment is |
| disabled by default. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_dynamic(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{logical function omp_get_dynamic()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_set_dynamic}, @ref{OMP_DYNAMIC} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.8. |
| @end table |
| |
| |
| |
| @node omp_get_cancellation |
| @subsection @code{omp_get_cancellation} -- Whether cancellation support is enabled |
| @table @asis |
| @item @emph{Description}: |
| This function returns @code{true} if cancellation is activated, @code{false} |
| otherwise. Here, @code{true} and @code{false} represent their language-specific |
| counterparts. Unless @env{OMP_CANCELLATION} is set true, cancellations are |
| deactivated. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_cancellation(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{logical function omp_get_cancellation()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_CANCELLATION} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.9. |
| @end table |
| |
| |
| |
| @node omp_set_nested |
| @subsection @code{omp_set_nested} -- Enable/disable nested parallel regions |
| @table @asis |
| @item @emph{Description}: |
| Enable or disable nested parallel regions, i.e., whether team members |
| are allowed to create new teams. The function takes the language-specific |
| equivalent of @code{true} and @code{false}, where @code{true} enables |
| dynamic adjustment of team sizes and @code{false} disables it. |
| |
| Enabling nested parallel regions also sets the maximum number of |
| active nested regions to the maximum supported. Disabling nested parallel |
| regions sets the maximum number of active nested regions to one. |
| |
| Note that the @code{omp_set_nested} API routine was deprecated |
| in the OpenMP specification 5.2 in favor of @code{omp_set_max_active_levels}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_nested(int nested);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_nested(nested)} |
| @item @tab @code{logical, intent(in) :: nested} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_nested}, @ref{omp_set_max_active_levels}, |
| @ref{OMP_MAX_ACTIVE_LEVELS}, @ref{OMP_NESTED} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.10. |
| @end table |
| |
| |
| |
| @node omp_get_nested |
| @subsection @code{omp_get_nested} -- Nested parallel regions |
| @table @asis |
| @item @emph{Description}: |
| This function returns @code{true} if nested parallel regions are |
| enabled, @code{false} otherwise. Here, @code{true} and @code{false} |
| represent their language-specific counterparts. |
| |
| The state of nested parallel regions at startup depends on several |
| environment variables. If @env{OMP_MAX_ACTIVE_LEVELS} is defined |
| and is set to greater than one, then nested parallel regions will be |
| enabled. If not defined, then the value of the @env{OMP_NESTED} |
| environment variable will be followed if defined. If neither are |
| defined, then if either @env{OMP_NUM_THREADS} or @env{OMP_PROC_BIND} |
| are defined with a list of more than one value, then nested parallel |
| regions are enabled. If none of these are defined, then nested parallel |
| regions are disabled by default. |
| |
| Nested parallel regions can be enabled or disabled at runtime using |
| @code{omp_set_nested}, or by setting the maximum number of nested |
| regions with @code{omp_set_max_active_levels} to one to disable, or |
| above one to enable. |
| |
| Note that the @code{omp_get_nested} API routine was deprecated |
| in the OpenMP specification 5.2 in favor of @code{omp_get_max_active_levels}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_nested(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{logical function omp_get_nested()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_max_active_levels}, @ref{omp_set_nested}, |
| @ref{OMP_MAX_ACTIVE_LEVELS}, @ref{OMP_NESTED} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.11. |
| @end table |
| |
| |
| |
| @node omp_set_schedule |
| @subsection @code{omp_set_schedule} -- Set the runtime scheduling method |
| @table @asis |
| @item @emph{Description}: |
| Sets the runtime scheduling method. The @var{kind} argument can have the |
| value @code{omp_sched_static}, @code{omp_sched_dynamic}, |
| @code{omp_sched_guided} or @code{omp_sched_auto}. Except for |
| @code{omp_sched_auto}, the chunk size is set to the value of |
| @var{chunk_size} if positive, or to the default value if zero or negative. |
| For @code{omp_sched_auto} the @var{chunk_size} argument is ignored. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_schedule(omp_sched_t kind, int chunk_size);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_schedule(kind, chunk_size)} |
| @item @tab @code{integer(kind=omp_sched_kind) kind} |
| @item @tab @code{integer chunk_size} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_schedule} |
| @ref{OMP_SCHEDULE} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.12. |
| @end table |
| |
| |
| |
| @node omp_get_schedule |
| @subsection @code{omp_get_schedule} -- Obtain the runtime scheduling method |
| @table @asis |
| @item @emph{Description}: |
| Obtain the runtime scheduling method. The @var{kind} argument is set to |
| @code{omp_sched_static}, @code{omp_sched_dynamic}, |
| @code{omp_sched_guided} or @code{omp_sched_auto}. The second argument, |
| @var{chunk_size}, is set to the chunk size. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_get_schedule(omp_sched_t *kind, int *chunk_size);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_get_schedule(kind, chunk_size)} |
| @item @tab @code{integer(kind=omp_sched_kind) kind} |
| @item @tab @code{integer chunk_size} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_set_schedule}, @ref{OMP_SCHEDULE} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.13. |
| @end table |
| |
| |
| @node omp_get_teams_thread_limit |
| @subsection @code{omp_get_teams_thread_limit} -- Maximum number of threads imposed by teams |
| @table @asis |
| @item @emph{Description}: |
| Return the maximum number of threads that are able to participate in |
| each team created by a teams construct. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_teams_thread_limit(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_teams_thread_limit()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_set_teams_thread_limit}, @ref{OMP_TEAMS_THREAD_LIMIT} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.4.6. |
| @end table |
| |
| |
| |
| @node omp_get_supported_active_levels |
| @subsection @code{omp_get_supported_active_levels} -- Maximum number of active regions supported |
| @table @asis |
| @item @emph{Description}: |
| This function returns the maximum number of nested, active parallel regions |
| supported by this implementation. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_supported_active_levels(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_supported_active_levels()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_max_active_levels}, @ref{omp_set_max_active_levels} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.2.15. |
| @end table |
| |
| |
| |
| @node omp_set_max_active_levels |
| @subsection @code{omp_set_max_active_levels} -- Limits the number of active parallel regions |
| @table @asis |
| @item @emph{Description}: |
| This function limits the maximum allowed number of nested, active |
| parallel regions. @var{max_levels} must be less or equal to |
| the value returned by @code{omp_get_supported_active_levels}. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_max_active_levels(int max_levels);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_max_active_levels(max_levels)} |
| @item @tab @code{integer max_levels} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_max_active_levels}, @ref{omp_get_active_level}, |
| @ref{omp_get_supported_active_levels} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.15. |
| @end table |
| |
| |
| |
| @node omp_get_max_active_levels |
| @subsection @code{omp_get_max_active_levels} -- Current maximum number of active regions |
| @table @asis |
| @item @emph{Description}: |
| This function obtains the maximum allowed number of nested, active parallel regions. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_max_active_levels(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_max_active_levels()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_set_max_active_levels}, @ref{omp_get_active_level} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.16. |
| @end table |
| |
| |
| @node omp_get_level |
| @subsection @code{omp_get_level} -- Obtain the current nesting level |
| @table @asis |
| @item @emph{Description}: |
| This function returns the nesting level for the parallel blocks, |
| which enclose the calling call. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_level(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_level()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_active_level} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.17. |
| @end table |
| |
| |
| |
| @node omp_get_ancestor_thread_num |
| @subsection @code{omp_get_ancestor_thread_num} -- Ancestor thread ID |
| @table @asis |
| @item @emph{Description}: |
| This function returns the thread identification number for the given |
| nesting level of the current thread. For values of @var{level} outside |
| zero to @code{omp_get_level} -1 is returned; if @var{level} is |
| @code{omp_get_level} the result is identical to @code{omp_get_thread_num}. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_ancestor_thread_num(int level);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_ancestor_thread_num(level)} |
| @item @tab @code{integer level} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_level}, @ref{omp_get_thread_num}, @ref{omp_get_team_size} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.18. |
| @end table |
| |
| |
| |
| @node omp_get_team_size |
| @subsection @code{omp_get_team_size} -- Number of threads in a team |
| @table @asis |
| @item @emph{Description}: |
| This function returns the number of threads in a thread team to which |
| either the current thread or its ancestor belongs. For values of @var{level} |
| outside zero to @code{omp_get_level}, -1 is returned; if @var{level} is zero, |
| 1 is returned, and for @code{omp_get_level}, the result is identical |
| to @code{omp_get_num_threads}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_team_size(int level);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_team_size(level)} |
| @item @tab @code{integer level} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_num_threads}, @ref{omp_get_level}, @ref{omp_get_ancestor_thread_num} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.19. |
| @end table |
| |
| |
| |
| @node omp_get_active_level |
| @subsection @code{omp_get_active_level} -- Number of parallel regions |
| @table @asis |
| @item @emph{Description}: |
| This function returns the nesting level for the active parallel blocks, |
| which enclose the calling call. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_active_level(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_active_level()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_level}, @ref{omp_get_max_active_levels}, @ref{omp_set_max_active_levels} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.20. |
| @end table |
| |
| |
| |
| @node Thread Affinity Routines |
| @section Thread Affinity Routines |
| |
| Routines controlling and accessing thread-affinity policies. |
| They have C linkage and do not throw exceptions. |
| |
| @menu |
| * omp_get_proc_bind:: Whether threads may be moved between CPUs |
| @c * omp_get_num_places:: <fixme> |
| @c * omp_get_place_num_procs:: <fixme> |
| @c * omp_get_place_proc_ids:: <fixme> |
| @c * omp_get_place_num:: <fixme> |
| @c * omp_get_partition_num_places:: <fixme> |
| @c * omp_get_partition_place_nums:: <fixme> |
| @c * omp_set_affinity_format:: <fixme> |
| @c * omp_get_affinity_format:: <fixme> |
| @c * omp_display_affinity:: <fixme> |
| @c * omp_capture_affinity:: <fixme> |
| @end menu |
| |
| |
| |
| @node omp_get_proc_bind |
| @subsection @code{omp_get_proc_bind} -- Whether threads may be moved between CPUs |
| @table @asis |
| @item @emph{Description}: |
| This functions returns the currently active thread affinity policy, which is |
| set via @env{OMP_PROC_BIND}. Possible values are @code{omp_proc_bind_false}, |
| @code{omp_proc_bind_true}, @code{omp_proc_bind_primary}, |
| @code{omp_proc_bind_master}, @code{omp_proc_bind_close} and @code{omp_proc_bind_spread}, |
| where @code{omp_proc_bind_master} is an alias for @code{omp_proc_bind_primary}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{omp_proc_bind_t omp_get_proc_bind(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer(kind=omp_proc_bind_kind) function omp_get_proc_bind()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_PROC_BIND}, @ref{OMP_PLACES}, @ref{GOMP_CPU_AFFINITY}, |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.22. |
| @end table |
| |
| |
| |
| @node Teams Region Routines |
| @section Teams Region Routines |
| |
| Routines controlling the league of teams that are executed in a @code{teams} |
| region. They have C linkage and do not throw exceptions. |
| |
| @menu |
| * omp_get_num_teams:: Number of teams |
| * omp_get_team_num:: Get team number |
| * omp_set_num_teams:: Set upper teams limit for teams region |
| * omp_get_max_teams:: Maximum number of teams for teams region |
| * omp_set_teams_thread_limit:: Set upper thread limit for teams construct |
| * omp_get_thread_limit:: Maximum number of threads |
| @end menu |
| |
| |
| |
| @node omp_get_num_teams |
| @subsection @code{omp_get_num_teams} -- Number of teams |
| @table @asis |
| @item @emph{Description}: |
| Returns the number of teams in the current team region. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_num_teams(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_num_teams()} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.32. |
| @end table |
| |
| |
| |
| @node omp_get_team_num |
| @subsection @code{omp_get_team_num} -- Get team number |
| @table @asis |
| @item @emph{Description}: |
| Returns the team number of the calling thread. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_team_num(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_team_num()} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.33. |
| @end table |
| |
| |
| |
| @node omp_set_num_teams |
| @subsection @code{omp_set_num_teams} -- Set upper teams limit for teams construct |
| @table @asis |
| @item @emph{Description}: |
| Specifies the upper bound for number of teams created by the teams construct |
| which does not specify a @code{num_teams} clause. The |
| argument of @code{omp_set_num_teams} shall be a positive integer. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_num_teams(int num_teams);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_num_teams(num_teams)} |
| @item @tab @code{integer, intent(in) :: num_teams} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_NUM_TEAMS}, @ref{omp_get_num_teams}, @ref{omp_get_max_teams} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.4.3. |
| @end table |
| |
| |
| |
| @node omp_get_max_teams |
| @subsection @code{omp_get_max_teams} -- Maximum number of teams of teams region |
| @table @asis |
| @item @emph{Description}: |
| Return the maximum number of teams used for the teams region |
| that does not use the clause @code{num_teams}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_max_teams(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_max_teams()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_set_num_teams}, @ref{omp_get_num_teams} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.4.4. |
| @end table |
| |
| |
| |
| @node omp_set_teams_thread_limit |
| @subsection @code{omp_set_teams_thread_limit} -- Set upper thread limit for teams construct |
| @table @asis |
| @item @emph{Description}: |
| Specifies the upper bound for number of threads that are available |
| for each team created by the teams construct which does not specify a |
| @code{thread_limit} clause. The argument of |
| @code{omp_set_teams_thread_limit} shall be a positive integer. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_teams_thread_limit(int thread_limit);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_teams_thread_limit(thread_limit)} |
| @item @tab @code{integer, intent(in) :: thread_limit} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_TEAMS_THREAD_LIMIT}, @ref{omp_get_teams_thread_limit}, @ref{omp_get_thread_limit} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.4.5. |
| @end table |
| |
| |
| |
| @node omp_get_thread_limit |
| @subsection @code{omp_get_thread_limit} -- Maximum number of threads |
| @table @asis |
| @item @emph{Description}: |
| Return the maximum number of threads of the program. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_thread_limit(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_thread_limit()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_max_threads}, @ref{OMP_THREAD_LIMIT} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.14. |
| @end table |
| |
| |
| |
| @node Tasking Routines |
| @section Tasking Routines |
| |
| Routines relating to explicit tasks. |
| They have C linkage and do not throw exceptions. |
| |
| @menu |
| * omp_get_max_task_priority:: Maximum task priority value that can be set |
| * omp_in_explicit_task:: Whether a given task is an explicit task |
| * omp_in_final:: Whether in final or included task region |
| @c * omp_is_free_agent:: <fixme>/TR12 |
| @c * omp_ancestor_is_free_agent:: <fixme>/TR12 |
| @end menu |
| |
| |
| |
| @node omp_get_max_task_priority |
| @subsection @code{omp_get_max_task_priority} -- Maximum priority value |
| that can be set for tasks. |
| @table @asis |
| @item @emph{Description}: |
| This function obtains the maximum allowed priority number for tasks. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_max_task_priority(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_max_task_priority()} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.29. |
| @end table |
| |
| |
| |
| @node omp_in_explicit_task |
| @subsection @code{omp_in_explicit_task} -- Whether a given task is an explicit task |
| @table @asis |
| @item @emph{Description}: |
| The function returns the @var{explicit-task-var} ICV; it returns true when the |
| encountering task was generated by a task-generating construct such as |
| @code{target}, @code{task} or @code{taskloop}. Otherwise, the encountering task |
| is in an implicit task region such as generated by the implicit or explicit |
| @code{parallel} region and @code{omp_in_explicit_task} returns false. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_in_explicit_task(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{logical function omp_in_explicit_task()} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.2}, Section 18.5.2. |
| @end table |
| |
| |
| |
| @node omp_in_final |
| @subsection @code{omp_in_final} -- Whether in final or included task region |
| @table @asis |
| @item @emph{Description}: |
| This function returns @code{true} if currently running in a final |
| or included task region, @code{false} otherwise. Here, @code{true} |
| and @code{false} represent their language-specific counterparts. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_in_final(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{logical function omp_in_final()} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.21. |
| @end table |
| |
| |
| |
| @c @node Resource Relinquishing Routines |
| @c @section Resource Relinquishing Routines |
| @c |
| @c Routines releasing resources used by the OpenMP runtime. |
| @c They have C linkage and do not throw exceptions. |
| @c |
| @c @menu |
| @c * omp_pause_resource:: <fixme> |
| @c * omp_pause_resource_all:: <fixme> |
| @c @end menu |
| |
| @node Device Information Routines |
| @section Device Information Routines |
| |
| Routines related to devices available to an OpenMP program. |
| They have C linkage and do not throw exceptions. |
| |
| @menu |
| * omp_get_num_procs:: Number of processors online |
| @c * omp_get_max_progress_width:: <fixme>/TR11 |
| * omp_set_default_device:: Set the default device for target regions |
| * omp_get_default_device:: Get the default device for target regions |
| * omp_get_num_devices:: Number of target devices |
| * omp_get_device_num:: Get device that current thread is running on |
| * omp_is_initial_device:: Whether executing on the host device |
| * omp_get_initial_device:: Device number of host device |
| @end menu |
| |
| |
| |
| @node omp_get_num_procs |
| @subsection @code{omp_get_num_procs} -- Number of processors online |
| @table @asis |
| @item @emph{Description}: |
| Returns the number of processors online on that device. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_num_procs(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_num_procs()} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.5. |
| @end table |
| |
| |
| |
| @node omp_set_default_device |
| @subsection @code{omp_set_default_device} -- Set the default device for target regions |
| @table @asis |
| @item @emph{Description}: |
| Set the default device for target regions without device clause. The argument |
| shall be a nonnegative device number. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_default_device(int device_num);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_default_device(device_num)} |
| @item @tab @code{integer device_num} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_DEFAULT_DEVICE}, @ref{omp_get_default_device} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.29. |
| @end table |
| |
| |
| |
| @node omp_get_default_device |
| @subsection @code{omp_get_default_device} -- Get the default device for target regions |
| @table @asis |
| @item @emph{Description}: |
| Get the default device for target regions without device clause. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_default_device(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_default_device()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_DEFAULT_DEVICE}, @ref{omp_set_default_device} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.30. |
| @end table |
| |
| |
| |
| @node omp_get_num_devices |
| @subsection @code{omp_get_num_devices} -- Number of target devices |
| @table @asis |
| @item @emph{Description}: |
| Returns the number of target devices. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_num_devices(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_num_devices()} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.31. |
| @end table |
| |
| |
| |
| @node omp_get_device_num |
| @subsection @code{omp_get_device_num} -- Return device number of current device |
| @table @asis |
| @item @emph{Description}: |
| This function returns a device number that represents the device that the |
| current thread is executing on. For OpenMP 5.0, this must be equal to the |
| value returned by the @code{omp_get_initial_device} function when called |
| from the host. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_device_num(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_device_num()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_initial_device} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.2.37. |
| @end table |
| |
| |
| |
| @node omp_is_initial_device |
| @subsection @code{omp_is_initial_device} -- Whether executing on the host device |
| @table @asis |
| @item @emph{Description}: |
| This function returns @code{true} if currently running on the host device, |
| @code{false} otherwise. Here, @code{true} and @code{false} represent |
| their language-specific counterparts. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_is_initial_device(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{logical function omp_is_initial_device()} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.34. |
| @end table |
| |
| |
| |
| @node omp_get_initial_device |
| @subsection @code{omp_get_initial_device} -- Return device number of initial device |
| @table @asis |
| @item @emph{Description}: |
| This function returns a device number that represents the host device. |
| For OpenMP 5.1, this must be equal to the value returned by the |
| @code{omp_get_num_devices} function. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_get_initial_device(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function omp_get_initial_device()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_num_devices} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.35. |
| @end table |
| |
| |
| |
| @node Device Memory Routines |
| @section Device Memory Routines |
| |
| Routines related to memory allocation and managing corresponding |
| pointers on devices. They have C linkage and do not throw exceptions. |
| |
| @menu |
| * omp_target_alloc:: Allocate device memory |
| * omp_target_free:: Free device memory |
| * omp_target_is_present:: Check whether storage is mapped |
| @c * omp_target_is_accessible:: <fixme> |
| @c * omp_target_memcpy:: <fixme> |
| @c * omp_target_memcpy_rect:: <fixme> |
| @c * omp_target_memcpy_async:: <fixme> |
| @c * omp_target_memcpy_rect_async:: <fixme> |
| @c * omp_target_memset:: <fixme>/TR12 |
| @c * omp_target_memset_async:: <fixme>/TR12 |
| * omp_target_associate_ptr:: Associate a device pointer with a host pointer |
| * omp_target_disassociate_ptr:: Remove device--host pointer association |
| * omp_get_mapped_ptr:: Return device pointer to a host pointer |
| @end menu |
| |
| |
| |
| @node omp_target_alloc |
| @subsection @code{omp_target_alloc} -- Allocate device memory |
| @table @asis |
| @item @emph{Description}: |
| This routine allocates @var{size} bytes of memory in the device environment |
| associated with the device number @var{device_num}. If successful, a device |
| pointer is returned, otherwise a null pointer. |
| |
| In GCC, when the device is the host or the device shares memory with the host, |
| the memory is allocated on the host; in that case, when @var{size} is zero, |
| either NULL or a unique pointer value that can later be successfully passed to |
| @code{omp_target_free} is returned. When the allocation is not performed on |
| the host, a null pointer is returned when @var{size} is zero; in that case, |
| additionally a diagnostic might be printed to standard error (stderr). |
| |
| Running this routine in a @code{target} region except on the initial device |
| is not supported. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void *omp_target_alloc(size_t size, int device_num)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{type(c_ptr) function omp_target_alloc(size, device_num) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int, c_size_t} |
| @item @tab @code{integer(c_size_t), value :: size} |
| @item @tab @code{integer(c_int), value :: device_num} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_target_free}, @ref{omp_target_associate_ptr} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.1 |
| @end table |
| |
| |
| |
| @node omp_target_free |
| @subsection @code{omp_target_free} -- Free device memory |
| @table @asis |
| @item @emph{Description}: |
| This routine frees memory allocated by the @code{omp_target_alloc} routine. |
| The @var{device_ptr} argument must be either a null pointer or a device pointer |
| returned by @code{omp_target_alloc} for the specified @code{device_num}. The |
| device number @var{device_num} must be a conforming device number. |
| |
| Running this routine in a @code{target} region except on the initial device |
| is not supported. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_target_free(void *device_ptr, int device_num)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_target_free(device_ptr, device_num) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int} |
| @item @tab @code{type(c_ptr), value :: device_ptr} |
| @item @tab @code{integer(c_int), value :: device_num} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_target_alloc}, @ref{omp_target_disassociate_ptr} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.2 |
| @end table |
| |
| |
| |
| @node omp_target_is_present |
| @subsection @code{omp_target_is_present} -- Check whether storage is mapped |
| @table @asis |
| @item @emph{Description}: |
| This routine tests whether storage, identified by the host pointer @var{ptr} |
| is mapped to the device specified by @var{device_num}. If so, it returns |
| @emph{true} and otherwise @emph{false}. |
| |
| In GCC, this includes self mapping such that @code{omp_target_is_present} |
| returns @emph{true} when @var{device_num} specifies the host or when the host |
| and the device share memory. If @var{ptr} is a null pointer, @var{true} is |
| returned and if @var{device_num} is an invalid device number, @var{false} is |
| returned. |
| |
| If those conditions do not apply, @emph{true} is returned if the association has |
| been established by an explicit or implicit @code{map} clause, the |
| @code{declare target} directive or a call to the @code{omp_target_associate_ptr} |
| routine. |
| |
| Running this routine in a @code{target} region except on the initial device |
| is not supported. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_target_is_present(const void *ptr,} |
| @item @tab @code{ int device_num)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer(c_int) function omp_target_is_present(ptr, &} |
| @item @tab @code{ device_num) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int} |
| @item @tab @code{type(c_ptr), value :: ptr} |
| @item @tab @code{integer(c_int), value :: device_num} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_target_associate_ptr} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.3 |
| @end table |
| |
| |
| |
| @node omp_target_associate_ptr |
| @subsection @code{omp_target_associate_ptr} -- Associate a device pointer with a host pointer |
| @table @asis |
| @item @emph{Description}: |
| This routine associates storage on the host with storage on a device identified |
| by @var{device_num}. The device pointer is usually obtained by calling |
| @code{omp_target_alloc} or by other means (but not by using the @code{map} |
| clauses or the @code{declare target} directive). The host pointer should point |
| to memory that has a storage size of at least @var{size}. |
| |
| The @var{device_offset} parameter specifies the offset into @var{device_ptr} |
| that is used as the base address for the device side of the mapping; the |
| storage size should be at least @var{device_offset} plus @var{size}. |
| |
| After the association, the host pointer can be used in a @code{map} clause and |
| in the @code{to} and @code{from} clauses of the @code{target update} directive |
| to transfer data between the associated pointers. The reference count of such |
| associated storage is infinite. The association can be removed by calling |
| @code{omp_target_disassociate_ptr} which should be done before the lifetime |
| of either either storage ends. |
| |
| The routine returns nonzero (@code{EINVAL}) when the @var{device_num} invalid, |
| for when the initial device or the associated device shares memory with the |
| host. @code{omp_target_associate_ptr} returns zero if @var{host_ptr} points |
| into already associated storage that is fully inside of a previously associated |
| memory. Otherwise, if the association was successful zero is returned; if none |
| of the cases above apply, nonzero (@code{EINVAL}) is returned. |
| |
| The @code{omp_target_is_present} routine can be used to test whether |
| associated storage for a device pointer exists. |
| |
| Running this routine in a @code{target} region except on the initial device |
| is not supported. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_target_associate_ptr(const void *host_ptr,} |
| @item @tab @code{ const void *device_ptr,} |
| @item @tab @code{ size_t size,} |
| @item @tab @code{ size_t device_offset,} |
| @item @tab @code{ int device_num)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer(c_int) function omp_target_associate_ptr(host_ptr, &} |
| @item @tab @code{ device_ptr, size, device_offset, device_num) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int, c_size_t} |
| @item @tab @code{type(c_ptr), value :: host_ptr, device_ptr} |
| @item @tab @code{integer(c_size_t), value :: size, device_offset} |
| @item @tab @code{integer(c_int), value :: device_num} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_target_disassociate_ptr}, @ref{omp_target_is_present}, |
| @ref{omp_target_alloc} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.9 |
| @end table |
| |
| |
| |
| @node omp_target_disassociate_ptr |
| @subsection @code{omp_target_disassociate_ptr} -- Remove device--host pointer association |
| @table @asis |
| @item @emph{Description}: |
| This routine removes the storage association established by calling |
| @code{omp_target_associate_ptr} and sets the reference count to zero, |
| even if @code{omp_target_associate_ptr} was invoked multiple times for |
| for host pointer @code{ptr}. If applicable, the device memory needs |
| to be freed by the user. |
| |
| If an associated device storage location for the @var{device_num} was |
| found and has infinite reference count, the association is removed and |
| zero is returned. In all other cases, nonzero (@code{EINVAL}) is returned |
| and no other action is taken. |
| |
| Note that passing a host pointer where the association to the device pointer |
| was established with the @code{declare target} directive yields undefined |
| behavior. |
| |
| Running this routine in a @code{target} region except on the initial device |
| is not supported. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_target_disassociate_ptr(const void *ptr,} |
| @item @tab @code{ int device_num)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer(c_int) function omp_target_disassociate_ptr(ptr, &} |
| @item @tab @code{ device_num) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int} |
| @item @tab @code{type(c_ptr), value :: ptr} |
| @item @tab @code{integer(c_int), value :: device_num} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_target_associate_ptr} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.10 |
| @end table |
| |
| |
| |
| @node omp_get_mapped_ptr |
| @subsection @code{omp_get_mapped_ptr} -- Return device pointer to a host pointer |
| @table @asis |
| @item @emph{Description}: |
| If the device number is refers to the initial device or to a device with |
| memory accessible from the host (shared memory), the @code{omp_get_mapped_ptr} |
| routines returns the value of the passed @var{ptr}. Otherwise, if associated |
| storage to the passed host pointer @var{ptr} exists on device associated with |
| @var{device_num}, it returns that pointer. In all other cases and in cases of |
| an error, a null pointer is returned. |
| |
| The association of storage location is established either via an explicit or |
| implicit @code{map} clause, the @code{declare target} directive or the |
| @code{omp_target_associate_ptr} routine. |
| |
| Running this routine in a @code{target} region except on the initial device |
| is not supported. |
| |
| @item @emph{C/C++} |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void *omp_get_mapped_ptr(const void *ptr, int device_num);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{type(c_ptr) function omp_get_mapped_ptr(ptr, device_num) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int} |
| @item @tab @code{type(c_ptr), value :: ptr} |
| @item @tab @code{integer(c_int), value :: device_num} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_target_associate_ptr} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.11 |
| @end table |
| |
| |
| |
| @node Lock Routines |
| @section Lock Routines |
| |
| Initialize, set, test, unset and destroy simple and nested locks. |
| The routines have C linkage and do not throw exceptions. |
| |
| @menu |
| * omp_init_lock:: Initialize simple lock |
| * omp_init_nest_lock:: Initialize nested lock |
| @c * omp_init_lock_with_hint:: <fixme> |
| @c * omp_init_nest_lock_with_hint:: <fixme> |
| * omp_destroy_lock:: Destroy simple lock |
| * omp_destroy_nest_lock:: Destroy nested lock |
| * omp_set_lock:: Wait for and set simple lock |
| * omp_set_nest_lock:: Wait for and set simple lock |
| * omp_unset_lock:: Unset simple lock |
| * omp_unset_nest_lock:: Unset nested lock |
| * omp_test_lock:: Test and set simple lock if available |
| * omp_test_nest_lock:: Test and set nested lock if available |
| @end menu |
| |
| |
| |
| @node omp_init_lock |
| @subsection @code{omp_init_lock} -- Initialize simple lock |
| @table @asis |
| @item @emph{Description}: |
| Initialize a simple lock. After initialization, the lock is in |
| an unlocked state. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_init_lock(omp_lock_t *lock);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_init_lock(svar)} |
| @item @tab @code{integer(omp_lock_kind), intent(out) :: svar} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_destroy_lock} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.1. |
| @end table |
| |
| |
| |
| @node omp_init_nest_lock |
| @subsection @code{omp_init_nest_lock} -- Initialize nested lock |
| @table @asis |
| @item @emph{Description}: |
| Initialize a nested lock. After initialization, the lock is in |
| an unlocked state and the nesting count is set to zero. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_init_nest_lock(omp_nest_lock_t *lock);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_init_nest_lock(nvar)} |
| @item @tab @code{integer(omp_nest_lock_kind), intent(out) :: nvar} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_destroy_nest_lock} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.1. |
| @end table |
| |
| |
| |
| @node omp_destroy_lock |
| @subsection @code{omp_destroy_lock} -- Destroy simple lock |
| @table @asis |
| @item @emph{Description}: |
| Destroy a simple lock. In order to be destroyed, a simple lock must be |
| in the unlocked state. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_destroy_lock(omp_lock_t *lock);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_destroy_lock(svar)} |
| @item @tab @code{integer(omp_lock_kind), intent(inout) :: svar} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_init_lock} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.3. |
| @end table |
| |
| |
| |
| @node omp_destroy_nest_lock |
| @subsection @code{omp_destroy_nest_lock} -- Destroy nested lock |
| @table @asis |
| @item @emph{Description}: |
| Destroy a nested lock. In order to be destroyed, a nested lock must be |
| in the unlocked state and its nesting count must equal zero. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_destroy_nest_lock(omp_nest_lock_t *);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_destroy_nest_lock(nvar)} |
| @item @tab @code{integer(omp_nest_lock_kind), intent(inout) :: nvar} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_init_lock} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.3. |
| @end table |
| |
| |
| |
| @node omp_set_lock |
| @subsection @code{omp_set_lock} -- Wait for and set simple lock |
| @table @asis |
| @item @emph{Description}: |
| Before setting a simple lock, the lock variable must be initialized by |
| @code{omp_init_lock}. The calling thread is blocked until the lock |
| is available. If the lock is already held by the current thread, |
| a deadlock occurs. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_lock(omp_lock_t *lock);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_lock(svar)} |
| @item @tab @code{integer(omp_lock_kind), intent(inout) :: svar} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_init_lock}, @ref{omp_test_lock}, @ref{omp_unset_lock} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.4. |
| @end table |
| |
| |
| |
| @node omp_set_nest_lock |
| @subsection @code{omp_set_nest_lock} -- Wait for and set nested lock |
| @table @asis |
| @item @emph{Description}: |
| Before setting a nested lock, the lock variable must be initialized by |
| @code{omp_init_nest_lock}. The calling thread is blocked until the lock |
| is available. If the lock is already held by the current thread, the |
| nesting count for the lock is incremented. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_nest_lock(omp_nest_lock_t *lock);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_nest_lock(nvar)} |
| @item @tab @code{integer(omp_nest_lock_kind), intent(inout) :: nvar} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_init_nest_lock}, @ref{omp_unset_nest_lock} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.4. |
| @end table |
| |
| |
| |
| @node omp_unset_lock |
| @subsection @code{omp_unset_lock} -- Unset simple lock |
| @table @asis |
| @item @emph{Description}: |
| A simple lock about to be unset must have been locked by @code{omp_set_lock} |
| or @code{omp_test_lock} before. In addition, the lock must be held by the |
| thread calling @code{omp_unset_lock}. Then, the lock becomes unlocked. If one |
| or more threads attempted to set the lock before, one of them is chosen to, |
| again, set the lock to itself. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_unset_lock(omp_lock_t *lock);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_unset_lock(svar)} |
| @item @tab @code{integer(omp_lock_kind), intent(inout) :: svar} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_set_lock}, @ref{omp_test_lock} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.5. |
| @end table |
| |
| |
| |
| @node omp_unset_nest_lock |
| @subsection @code{omp_unset_nest_lock} -- Unset nested lock |
| @table @asis |
| @item @emph{Description}: |
| A nested lock about to be unset must have been locked by @code{omp_set_nested_lock} |
| or @code{omp_test_nested_lock} before. In addition, the lock must be held by the |
| thread calling @code{omp_unset_nested_lock}. If the nesting count drops to zero, the |
| lock becomes unlocked. If one ore more threads attempted to set the lock before, |
| one of them is chosen to, again, set the lock to itself. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_unset_nest_lock(omp_nest_lock_t *lock);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_unset_nest_lock(nvar)} |
| @item @tab @code{integer(omp_nest_lock_kind), intent(inout) :: nvar} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_set_nest_lock} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.5. |
| @end table |
| |
| |
| |
| @node omp_test_lock |
| @subsection @code{omp_test_lock} -- Test and set simple lock if available |
| @table @asis |
| @item @emph{Description}: |
| Before setting a simple lock, the lock variable must be initialized by |
| @code{omp_init_lock}. Contrary to @code{omp_set_lock}, @code{omp_test_lock} |
| does not block if the lock is not available. This function returns |
| @code{true} upon success, @code{false} otherwise. Here, @code{true} and |
| @code{false} represent their language-specific counterparts. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_test_lock(omp_lock_t *lock);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{logical function omp_test_lock(svar)} |
| @item @tab @code{integer(omp_lock_kind), intent(inout) :: svar} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_init_lock}, @ref{omp_set_lock}, @ref{omp_set_lock} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.6. |
| @end table |
| |
| |
| |
| @node omp_test_nest_lock |
| @subsection @code{omp_test_nest_lock} -- Test and set nested lock if available |
| @table @asis |
| @item @emph{Description}: |
| Before setting a nested lock, the lock variable must be initialized by |
| @code{omp_init_nest_lock}. Contrary to @code{omp_set_nest_lock}, |
| @code{omp_test_nest_lock} does not block if the lock is not available. |
| If the lock is already held by the current thread, the new nesting count |
| is returned. Otherwise, the return value equals zero. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int omp_test_nest_lock(omp_nest_lock_t *lock);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{logical function omp_test_nest_lock(nvar)} |
| @item @tab @code{integer(omp_nest_lock_kind), intent(inout) :: nvar} |
| @end multitable |
| |
| |
| @item @emph{See also}: |
| @ref{omp_init_lock}, @ref{omp_set_lock}, @ref{omp_set_lock} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.6. |
| @end table |
| |
| |
| |
| @node Timing Routines |
| @section Timing Routines |
| |
| Portable, thread-based, wall clock timer. |
| The routines have C linkage and do not throw exceptions. |
| |
| @menu |
| * omp_get_wtick:: Get timer precision. |
| * omp_get_wtime:: Elapsed wall clock time. |
| @end menu |
| |
| |
| |
| @node omp_get_wtick |
| @subsection @code{omp_get_wtick} -- Get timer precision |
| @table @asis |
| @item @emph{Description}: |
| Gets the timer precision, i.e., the number of seconds between two |
| successive clock ticks. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{double omp_get_wtick(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{double precision function omp_get_wtick()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_wtime} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.4.2. |
| @end table |
| |
| |
| |
| @node omp_get_wtime |
| @subsection @code{omp_get_wtime} -- Elapsed wall clock time |
| @table @asis |
| @item @emph{Description}: |
| Elapsed wall clock time in seconds. The time is measured per thread, no |
| guarantee can be made that two distinct threads measure the same time. |
| Time is measured from some "time in the past", which is an arbitrary time |
| guaranteed not to change during the execution of the program. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{double omp_get_wtime(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{double precision function omp_get_wtime()} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_wtick} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.4.1. |
| @end table |
| |
| |
| |
| @node Event Routine |
| @section Event Routine |
| |
| Support for event objects. |
| The routine has C linkage and do not throw exceptions. |
| |
| @menu |
| * omp_fulfill_event:: Fulfill and destroy an OpenMP event. |
| @end menu |
| |
| |
| |
| @node omp_fulfill_event |
| @subsection @code{omp_fulfill_event} -- Fulfill and destroy an OpenMP event |
| @table @asis |
| @item @emph{Description}: |
| Fulfill the event associated with the event handle argument. Currently, it |
| is only used to fulfill events generated by detach clauses on task |
| constructs - the effect of fulfilling the event is to allow the task to |
| complete. |
| |
| The result of calling @code{omp_fulfill_event} with an event handle other |
| than that generated by a detach clause is undefined. Calling it with an |
| event handle that has already been fulfilled is also undefined. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_fulfill_event(omp_event_handle_t event);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_fulfill_event(event)} |
| @item @tab @code{integer (kind=omp_event_handle_kind) :: event} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.5.1. |
| @end table |
| |
| |
| |
| @c @node Interoperability Routines |
| @c @section Interoperability Routines |
| @c |
| @c Routines to obtain properties from an @code{omp_interop_t} object. |
| @c They have C linkage and do not throw exceptions. |
| @c |
| @c @menu |
| @c * omp_get_num_interop_properties:: <fixme> |
| @c * omp_get_interop_int:: <fixme> |
| @c * omp_get_interop_ptr:: <fixme> |
| @c * omp_get_interop_str:: <fixme> |
| @c * omp_get_interop_name:: <fixme> |
| @c * omp_get_interop_type_desc:: <fixme> |
| @c * omp_get_interop_rc_desc:: <fixme> |
| @c @end menu |
| |
| @node Memory Management Routines |
| @section Memory Management Routines |
| |
| Routines to manage and allocate memory on the current device. |
| They have C linkage and do not throw exceptions. |
| |
| @menu |
| * omp_init_allocator:: Create an allocator |
| * omp_destroy_allocator:: Destroy an allocator |
| * omp_set_default_allocator:: Set the default allocator |
| * omp_get_default_allocator:: Get the default allocator |
| * omp_alloc:: Memory allocation with an allocator |
| * omp_aligned_alloc:: Memory allocation with an allocator and alignment |
| * omp_free:: Freeing memory allocated with OpenMP routines |
| * omp_calloc:: Allocate nullified memory with an allocator |
| * omp_aligned_calloc:: Allocate nullified aligned memory with an allocator |
| * omp_realloc:: Reallocate memory allocated with OpenMP routines |
| @c * omp_get_memspace_num_resources:: <fixme>/TR11 |
| @c * omp_get_submemspace:: <fixme>/TR11 |
| @end menu |
| |
| |
| |
| @node omp_init_allocator |
| @subsection @code{omp_init_allocator} -- Create an allocator |
| @table @asis |
| @item @emph{Description}: |
| Create an allocator that uses the specified memory space and has the specified |
| traits; if an allocator that fulfills the requirements cannot be created, |
| @code{omp_null_allocator} is returned. |
| |
| The predefined memory spaces and available traits can be found at |
| @ref{OMP_ALLOCATOR}, where the trait names have to be be prefixed by |
| @code{omp_atk_} (e.g. @code{omp_atk_pinned}) and the named trait values by |
| @code{omp_atv_} (e.g. @code{omp_atv_true}); additionally, @code{omp_atv_default} |
| may be used as trait value to specify that the default value should be used. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{omp_allocator_handle_t omp_init_allocator(} |
| @item @tab @code{ omp_memspace_handle_t memspace,} |
| @item @tab @code{ int ntraits,} |
| @item @tab @code{ const omp_alloctrait_t traits[]);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{function omp_init_allocator(memspace, ntraits, traits)} |
| @item @tab @code{integer (omp_allocator_handle_kind) :: omp_init_allocator} |
| @item @tab @code{integer (omp_memspace_handle_kind), intent(in) :: memspace} |
| @item @tab @code{integer, intent(in) :: ntraits} |
| @item @tab @code{type (omp_alloctrait), intent(in) :: traits(*)} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_destroy_allocator} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.2 |
| @end table |
| |
| |
| |
| @node omp_destroy_allocator |
| @subsection @code{omp_destroy_allocator} -- Destroy an allocator |
| @table @asis |
| @item @emph{Description}: |
| Releases all resources used by a memory allocator, which must not represent |
| a predefined memory allocator. Accessing memory after its allocator has been |
| destroyed has unspecified behavior. Passing @code{omp_null_allocator} to the |
| routine is permitted but has no effect. |
| |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_destroy_allocator (omp_allocator_handle_t allocator);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_destroy_allocator(allocator)} |
| @item @tab @code{integer (omp_allocator_handle_kind), intent(in) :: allocator} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_init_allocator} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.3 |
| @end table |
| |
| |
| |
| @node omp_set_default_allocator |
| @subsection @code{omp_set_default_allocator} -- Set the default allocator |
| @table @asis |
| @item @emph{Description}: |
| Sets the default allocator that is used when no allocator has been specified |
| in the @code{allocate} or @code{allocator} clause or if an OpenMP memory |
| routine is invoked with the @code{omp_null_allocator} allocator. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_set_default_allocator(omp_allocator_handle_t allocator);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_set_default_allocator(allocator)} |
| @item @tab @code{integer (omp_allocator_handle_kind), intent(in) :: allocator} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_get_default_allocator}, @ref{omp_init_allocator}, @ref{OMP_ALLOCATOR}, |
| @ref{Memory allocation} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.4 |
| @end table |
| |
| |
| |
| @node omp_get_default_allocator |
| @subsection @code{omp_get_default_allocator} -- Get the default allocator |
| @table @asis |
| @item @emph{Description}: |
| The routine returns the default allocator that is used when no allocator has |
| been specified in the @code{allocate} or @code{allocator} clause or if an |
| OpenMP memory routine is invoked with the @code{omp_null_allocator} allocator. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{omp_allocator_handle_t omp_get_default_allocator();} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{function omp_get_default_allocator()} |
| @item @tab @code{integer (omp_allocator_handle_kind) :: omp_get_default_allocator} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_set_default_allocator}, @ref{OMP_ALLOCATOR} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.5 |
| @end table |
| |
| |
| |
| @node omp_alloc |
| @subsection @code{omp_alloc} -- Memory allocation with an allocator |
| @table @asis |
| @item @emph{Description}: |
| Allocate memory with the specified allocator, which can either be a predefined |
| allocator, an allocator handle or @code{omp_null_allocator}. If the allocators |
| is @code{omp_null_allocator}, the allocator specified by the |
| @var{def-allocator-var} ICV is used. @var{size} must be a nonnegative number |
| denoting the number of bytes to be allocated; if @var{size} is zero, |
| @code{omp_alloc} will return a null pointer. If successful, a pointer to the |
| allocated memory is returned, otherwise the @code{fallback} trait of the |
| allocator determines the behavior. The content of the allocated memory is |
| unspecified. |
| |
| In @code{target} regions, either the @code{dynamic_allocators} clause must |
| appear on a @code{requires} directive in the same compilation unit -- or the |
| @var{allocator} argument may only be a constant expression with the value of |
| one of the predefined allocators and may not be @code{omp_null_allocator}. |
| |
| Memory allocated by @code{omp_alloc} must be freed using @code{omp_free}. |
| |
| @item @emph{C}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void* omp_alloc(size_t size,} |
| @item @tab @code{ omp_allocator_handle_t allocator)} |
| @end multitable |
| |
| @item @emph{C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void* omp_alloc(size_t size,} |
| @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{type(c_ptr) function omp_alloc(size, allocator) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr, c_size_t} |
| @item @tab @code{integer (c_size_t), value :: size} |
| @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_set_default_allocator}, |
| @ref{omp_free}, @ref{omp_init_allocator} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.6 |
| @end table |
| |
| |
| |
| @node omp_aligned_alloc |
| @subsection @code{omp_aligned_alloc} -- Memory allocation with an allocator and alignment |
| @table @asis |
| @item @emph{Description}: |
| Allocate memory with the specified allocator, which can either be a predefined |
| allocator, an allocator handle or @code{omp_null_allocator}. If the allocators |
| is @code{omp_null_allocator}, the allocator specified by the |
| @var{def-allocator-var} ICV is used. @var{alignment} must be a positive power |
| of two and @var{size} must be a nonnegative number that is a multiple of the |
| alignment and denotes the number of bytes to be allocated; if @var{size} is |
| zero, @code{omp_aligned_alloc} will return a null pointer. The alignment will |
| be at least the maximal value required by @code{alignment} trait of the |
| allocator and the value of the passed @var{alignment} argument. If successful, |
| a pointer to the allocated memory is returned, otherwise the @code{fallback} |
| trait of the allocator determines the behavior. The content of the allocated |
| memory is unspecified. |
| |
| In @code{target} regions, either the @code{dynamic_allocators} clause must |
| appear on a @code{requires} directive in the same compilation unit -- or the |
| @var{allocator} argument may only be a constant expression with the value of |
| one of the predefined allocators and may not be @code{omp_null_allocator}. |
| |
| Memory allocated by @code{omp_aligned_alloc} must be freed using |
| @code{omp_free}. |
| |
| @item @emph{C}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void* omp_aligned_alloc(size_t alignment,} |
| @item @tab @code{ size_t size,} |
| @item @tab @code{ omp_allocator_handle_t allocator)} |
| @end multitable |
| |
| @item @emph{C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void* omp_aligned_alloc(size_t alignment,} |
| @item @tab @code{ size_t size,} |
| @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{type(c_ptr) function omp_aligned_alloc(alignment, size, allocator) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr, c_size_t} |
| @item @tab @code{integer (c_size_t), value :: alignment, size} |
| @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_set_default_allocator}, |
| @ref{omp_free}, @ref{omp_init_allocator} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.13.6 |
| @end table |
| |
| |
| |
| @node omp_free |
| @subsection @code{omp_free} -- Freeing memory allocated with OpenMP routines |
| @table @asis |
| @item @emph{Description}: |
| The @code{omp_free} routine deallocates memory previously allocated by an |
| OpenMP memory-management routine. The @var{ptr} argument must point to such |
| memory or be a null pointer; if it is a null pointer, no operation is |
| performed. If specified, the @var{allocator} argument must be either the |
| memory allocator that was used for the allocation or @code{omp_null_allocator}; |
| if it is @code{omp_null_allocator}, the implementation will determine the value |
| automatically. |
| |
| Calling @code{omp_free} invokes undefined behavior if the memory |
| was already deallocated or when the used allocator has already been destroyed. |
| |
| @item @emph{C}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_free(void *ptr,} |
| @item @tab @code{ omp_allocator_handle_t allocator)} |
| @end multitable |
| |
| @item @emph{C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void omp_free(void *ptr,} |
| @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine omp_free(ptr, allocator) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr} |
| @item @tab @code{type (c_ptr), value :: ptr} |
| @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{omp_alloc}, @ref{omp_aligned_alloc}, @ref{omp_calloc}, |
| @ref{omp_aligned_calloc}, @ref{omp_realloc} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.7 |
| @end table |
| |
| |
| |
| @node omp_calloc |
| @subsection @code{omp_calloc} -- Allocate nullified memory with an allocator |
| @table @asis |
| @item @emph{Description}: |
| Allocate zero-initialized memory with the specified allocator, which can either |
| be a predefined allocator, an allocator handle or @code{omp_null_allocator}. If |
| the allocators is @code{omp_null_allocator}, the allocator specified by the |
| @var{def-allocator-var} ICV is used. The to-be allocated memory is for an |
| array with @var{nmemb} elements, each having a size of @var{size} bytes. Both |
| @var{nmemb} and @var{size} must be nonnegative numbers; if either of them is |
| zero, @code{omp_calloc} will return a null pointer. If successful, a pointer to |
| the zero-initialized allocated memory is returned, otherwise the @code{fallback} |
| trait of the allocator determines the behavior. |
| |
| In @code{target} regions, either the @code{dynamic_allocators} clause must |
| appear on a @code{requires} directive in the same compilation unit -- or the |
| @var{allocator} argument may only be a constant expression with the value of |
| one of the predefined allocators and may not be @code{omp_null_allocator}. |
| |
| Memory allocated by @code{omp_calloc} must be freed using @code{omp_free}. |
| |
| @item @emph{C}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void* omp_calloc(size_t nmemb, size_t size,} |
| @item @tab @code{ omp_allocator_handle_t allocator)} |
| @end multitable |
| |
| @item @emph{C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void* omp_calloc(size_t nmemb, size_t size,} |
| @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{type(c_ptr) function omp_calloc(nmemb, size, allocator) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr, c_size_t} |
| @item @tab @code{integer (c_size_t), value :: nmemb, size} |
| @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_set_default_allocator}, |
| @ref{omp_free}, @ref{omp_init_allocator} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.13.8 |
| @end table |
| |
| |
| |
| @node omp_aligned_calloc |
| @subsection @code{omp_aligned_calloc} -- Allocate aligned nullified memory with an allocator |
| @table @asis |
| @item @emph{Description}: |
| Allocate zero-initialized memory with the specified allocator, which can either |
| be a predefined allocator, an allocator handle or @code{omp_null_allocator}. If |
| the allocators is @code{omp_null_allocator}, the allocator specified by the |
| @var{def-allocator-var} ICV is used. The to-be allocated memory is for an |
| array with @var{nmemb} elements, each having a size of @var{size} bytes. Both |
| @var{nmemb} and @var{size} must be nonnegative numbers; if either of them is |
| zero, @code{omp_aligned_calloc} will return a null pointer. @var{alignment} |
| must be a positive power of two and @var{size} must be a multiple of the |
| alignment; the alignment will be at least the maximal value required by |
| @code{alignment} trait of the allocator and the value of the passed |
| @var{alignment} argument. If successful, a pointer to the zero-initialized |
| allocated memory is returned, otherwise the @code{fallback} trait of the |
| allocator determines the behavior. |
| |
| In @code{target} regions, either the @code{dynamic_allocators} clause must |
| appear on a @code{requires} directive in the same compilation unit -- or the |
| @var{allocator} argument may only be a constant expression with the value of |
| one of the predefined allocators and may not be @code{omp_null_allocator}. |
| |
| Memory allocated by @code{omp_aligned_calloc} must be freed using |
| @code{omp_free}. |
| |
| @item @emph{C}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void* omp_aligned_calloc(size_t nmemb, size_t size,} |
| @item @tab @code{ omp_allocator_handle_t allocator)} |
| @end multitable |
| |
| @item @emph{C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void* omp_aligned_calloc(size_t nmemb, size_t size,} |
| @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{type(c_ptr) function omp_aligned_calloc(nmemb, size, allocator) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr, c_size_t} |
| @item @tab @code{integer (c_size_t), value :: nmemb, size} |
| @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_set_default_allocator}, |
| @ref{omp_free}, @ref{omp_init_allocator} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.13.8 |
| @end table |
| |
| |
| |
| @node omp_realloc |
| @subsection @code{omp_realloc} -- Reallocate memory allocated with OpenMP routines |
| @table @asis |
| @item @emph{Description}: |
| The @code{omp_realloc} routine deallocates memory to which @var{ptr} points to |
| and allocates new memory with the specified @var{allocator} argument; the |
| new memory will have the content of the old memory up to the minimum of the |
| old size and the new @var{size}, otherwise the content of the returned memory |
| is unspecified. If the new allocator is the same as the old one, the routine |
| tries to resize the existing memory allocation, returning the same address as |
| @var{ptr} if successful. @var{ptr} must point to memory allocated by an OpenMP |
| memory-management routine. |
| |
| The @var{allocator} and @var{free_allocator} arguments must be a predefined |
| allocator, an allocator handle or @code{omp_null_allocator}. If |
| @var{free_allocator} is @code{omp_null_allocator}, the implementation |
| automatically determines the allocator used for the allocation of @var{ptr}. |
| If @var{allocator} is @code{omp_null_allocator} and @var{ptr} is is not a |
| null pointer, the same allocator as @code{free_allocator} is used and |
| when @var{ptr} is a null pointer the allocator specified by the |
| @var{def-allocator-var} ICV is used. |
| |
| The @var{size} must be a nonnegative number denoting the number of bytes to be |
| allocated; if @var{size} is zero, @code{omp_realloc} will return free the |
| memory and return a null pointer. When @var{size} is nonzero: if successful, |
| a pointer to the allocated memory is returned, otherwise the @code{fallback} |
| trait of the allocator determines the behavior. |
| |
| In @code{target} regions, either the @code{dynamic_allocators} clause must |
| appear on a @code{requires} directive in the same compilation unit -- or the |
| @var{free_allocator} and @var{allocator} arguments may only be a constant |
| expression with the value of one of the predefined allocators and may not be |
| @code{omp_null_allocator}. |
| |
| Memory allocated by @code{omp_realloc} must be freed using @code{omp_free}. |
| Calling @code{omp_free} invokes undefined behavior if the memory |
| was already deallocated or when the used allocator has already been destroyed. |
| |
| @item @emph{C}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void* omp_realloc(void *ptr, size_t size,} |
| @item @tab @code{ omp_allocator_handle_t allocator,} |
| @item @tab @code{ omp_allocator_handle_t free_allocator)} |
| @end multitable |
| |
| @item @emph{C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{void* omp_realloc(void *ptr, size_t size,} |
| @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator,} |
| @item @tab @code{ omp_allocator_handle_t free_allocator=omp_null_allocator)} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{type(c_ptr) function omp_realloc(ptr, size, allocator, free_allocator) bind(C)} |
| @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr, c_size_t} |
| @item @tab @code{type(C_ptr), value :: ptr} |
| @item @tab @code{integer (c_size_t), value :: size} |
| @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator, free_allocator} |
| @end multitable |
| |
| @item @emph{See also}: |
| @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_set_default_allocator}, |
| @ref{omp_free}, @ref{omp_init_allocator} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.9 |
| @end table |
| |
| |
| |
| @c @node Tool Control Routine |
| @c |
| @c FIXME |
| |
| @c @node Environment Display Routine |
| @c @section Environment Display Routine |
| @c |
| @c Routine to display the OpenMP number and the initial value of ICVs. |
| @c It has C linkage and do not throw exceptions. |
| @c |
| @c menu |
| @c * omp_display_env:: <fixme> |
| @c end menu |
| |
| @c --------------------------------------------------------------------- |
| @c OpenMP Environment Variables |
| @c --------------------------------------------------------------------- |
| |
| @node Environment Variables |
| @chapter OpenMP Environment Variables |
| |
| The environment variables which beginning with @env{OMP_} are defined by |
| section 4 of the OpenMP specification in version 4.5 or in a later version |
| of the specification, while those beginning with @env{GOMP_} are GNU extensions. |
| Most @env{OMP_} environment variables have an associated internal control |
| variable (ICV). |
| |
| For any OpenMP environment variable that sets an ICV and is neither |
| @code{OMP_DEFAULT_DEVICE} nor has global ICV scope, associated |
| device-specific environment variables exist. For them, the environment |
| variable without suffix affects the host. The suffix @code{_DEV_} followed |
| by a non-negative device number less that the number of available devices sets |
| the ICV for the corresponding device. The suffix @code{_DEV} sets the ICV |
| of all non-host devices for which a device-specific corresponding environment |
| variable has not been set while the @code{_ALL} suffix sets the ICV of all |
| host and non-host devices for which a more specific corresponding environment |
| variable is not set. |
| |
| @menu |
| * OMP_ALLOCATOR:: Set the default allocator |
| * OMP_AFFINITY_FORMAT:: Set the format string used for affinity display |
| * OMP_CANCELLATION:: Set whether cancellation is activated |
| * OMP_DISPLAY_AFFINITY:: Display thread affinity information |
| * OMP_DISPLAY_ENV:: Show OpenMP version and environment variables |
| * OMP_DEFAULT_DEVICE:: Set the device used in target regions |
| * OMP_DYNAMIC:: Dynamic adjustment of threads |
| * OMP_MAX_ACTIVE_LEVELS:: Set the maximum number of nested parallel regions |
| * OMP_MAX_TASK_PRIORITY:: Set the maximum task priority value |
| * OMP_NESTED:: Nested parallel regions |
| * OMP_NUM_TEAMS:: Specifies the number of teams to use by teams region |
| * OMP_NUM_THREADS:: Specifies the number of threads to use |
| * OMP_PROC_BIND:: Whether threads may be moved between CPUs |
| * OMP_PLACES:: Specifies on which CPUs the threads should be placed |
| * OMP_STACKSIZE:: Set default thread stack size |
| * OMP_SCHEDULE:: How threads are scheduled |
| * OMP_TARGET_OFFLOAD:: Controls offloading behavior |
| * OMP_TEAMS_THREAD_LIMIT:: Set the maximum number of threads imposed by teams |
| * OMP_THREAD_LIMIT:: Set the maximum number of threads |
| * OMP_WAIT_POLICY:: How waiting threads are handled |
| * GOMP_CPU_AFFINITY:: Bind threads to specific CPUs |
| * GOMP_DEBUG:: Enable debugging output |
| * GOMP_STACKSIZE:: Set default thread stack size |
| * GOMP_SPINCOUNT:: Set the busy-wait spin count |
| * GOMP_RTEMS_THREAD_POOLS:: Set the RTEMS specific thread pools |
| @end menu |
| |
| |
| @node OMP_ALLOCATOR |
| @section @env{OMP_ALLOCATOR} -- Set the default allocator |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{def-allocator-var} |
| @item @emph{Scope:} data environment |
| @item @emph{Description}: |
| Sets the default allocator that is used when no allocator has been specified |
| in the @code{allocate} or @code{allocator} clause or if an OpenMP memory |
| routine is invoked with the @code{omp_null_allocator} allocator. |
| If unset, @code{omp_default_mem_alloc} is used. |
| |
| The value can either be a predefined allocator or a predefined memory space |
| or a predefined memory space followed by a colon and a comma-separated list |
| of memory trait and value pairs, separated by @code{=}. |
| |
| Note: The corresponding device environment variables are currently not |
| supported. Therefore, the non-host @var{def-allocator-var} ICVs are always |
| initialized to @code{omp_default_mem_alloc}. However, on all devices, |
| the @code{omp_set_default_allocator} API routine can be used to change |
| value. |
| |
| @multitable @columnfractions .45 .45 |
| @headitem Predefined allocators @tab Associated predefined memory spaces |
| @item omp_default_mem_alloc @tab omp_default_mem_space |
| @item omp_large_cap_mem_alloc @tab omp_large_cap_mem_space |
| @item omp_const_mem_alloc @tab omp_const_mem_space |
| @item omp_high_bw_mem_alloc @tab omp_high_bw_mem_space |
| @item omp_low_lat_mem_alloc @tab omp_low_lat_mem_space |
| @item omp_cgroup_mem_alloc @tab omp_low_lat_mem_space (implementation defined) |
| @item omp_pteam_mem_alloc @tab omp_low_lat_mem_space (implementation defined) |
| @item omp_thread_mem_alloc @tab omp_low_lat_mem_space (implementation defined) |
| @end multitable |
| |
| The predefined allocators use the default values for the traits, |
| as listed below. Except that the last three allocators have the |
| @code{access} trait set to @code{cgroup}, @code{pteam}, and |
| @code{thread}, respectively. |
| |
| @multitable @columnfractions .25 .40 .25 |
| @headitem Trait @tab Allowed values @tab Default value |
| @item @code{sync_hint} @tab @code{contended}, @code{uncontended}, |
| @code{serialized}, @code{private} |
| @tab @code{contended} |
| @item @code{alignment} @tab Positive integer being a power of two |
| @tab 1 byte |
| @item @code{access} @tab @code{all}, @code{cgroup}, |
| @code{pteam}, @code{thread} |
| @tab @code{all} |
| @item @code{pool_size} @tab Positive integer |
| @tab See @ref{Memory allocation} |
| @item @code{fallback} @tab @code{default_mem_fb}, @code{null_fb}, |
| @code{abort_fb}, @code{allocator_fb} |
| @tab See below |
| @item @code{fb_data} @tab @emph{unsupported as it needs an allocator handle} |
| @tab (none) |
| @item @code{pinned} @tab @code{true}, @code{false} |
| @tab @code{false} |
| @item @code{partition} @tab @code{environment}, @code{nearest}, |
| @code{blocked}, @code{interleaved} |
| @tab @code{environment} |
| @end multitable |
| |
| For the @code{fallback} trait, the default value is @code{null_fb} for the |
| @code{omp_default_mem_alloc} allocator and any allocator that is associated |
| with device memory; for all other other allocators, it is @code{default_mem_fb} |
| by default. |
| |
| Examples: |
| @smallexample |
| OMP_ALLOCATOR=omp_high_bw_mem_alloc |
| OMP_ALLOCATOR=omp_large_cap_mem_space |
| OMP_ALLOCATOR=omp_low_lat_mem_space:pinned=true,partition=nearest |
| @end smallexample |
| |
| @item @emph{See also}: |
| @ref{Memory allocation}, @ref{omp_get_default_allocator}, |
| @ref{omp_set_default_allocator}, @ref{Offload-Target Specifics} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 6.21 |
| @end table |
| |
| |
| |
| @node OMP_AFFINITY_FORMAT |
| @section @env{OMP_AFFINITY_FORMAT} -- Set the format string used for affinity display |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{affinity-format-var} |
| @item @emph{Scope:} device |
| @item @emph{Description}: |
| Sets the format string used when displaying OpenMP thread affinity information. |
| Special values are output using @code{%} followed by an optional size |
| specification and then either the single-character field type or its long |
| name enclosed in curly braces; using @code{%%} displays a literal percent. |
| The size specification consists of an optional @code{0.} or @code{.} followed |
| by a positive integer, specifying the minimal width of the output. With |
| @code{0.} and numerical values, the output is padded with zeros on the left; |
| with @code{.}, the output is padded by spaces on the left; otherwise, the |
| output is padded by spaces on the right. If unset, the value is |
| ``@code{level %L thread %i affinity %A}''. |
| |
| Supported field types are: |
| |
| @multitable @columnfractions .10 .25 .60 |
| @item t @tab team_num @tab value returned by @code{omp_get_team_num} |
| @item T @tab num_teams @tab value returned by @code{omp_get_num_teams} |
| @item L @tab nesting_level @tab value returned by @code{omp_get_level} |
| @item n @tab thread_num @tab value returned by @code{omp_get_thread_num} |
| @item N @tab num_threads @tab value returned by @code{omp_get_num_threads} |
| @item a @tab ancestor_tnum |
| @tab value returned by |
| @code{omp_get_ancestor_thread_num(omp_get_level()-1)} |
| @item H @tab host @tab name of the host that executes the thread |
| @item P @tab process_id @tab process identifier |
| @item i @tab native_thread_id @tab native thread identifier |
| @item A @tab thread_affinity |
| @tab comma separated list of integer values or ranges, representing the |
| processors on which a process might execute, subject to affinity |
| mechanisms |
| @end multitable |
| |
| For instance, after setting |
| |
| @smallexample |
| OMP_AFFINITY_FORMAT="%0.2a!%n!%.4L!%N;%.2t;%0.2T;%@{team_num@};%@{num_teams@};%A" |
| @end smallexample |
| |
| with either @code{OMP_DISPLAY_AFFINITY} being set or when calling |
| @code{omp_display_affinity} with @code{NULL} or an empty string, the program |
| might display the following: |
| |
| @smallexample |
| 00!0! 1!4; 0;01;0;1;0-11 |
| 00!3! 1!4; 0;01;0;1;0-11 |
| 00!2! 1!4; 0;01;0;1;0-11 |
| 00!1! 1!4; 0;01;0;1;0-11 |
| @end smallexample |
| |
| @item @emph{See also}: |
| @ref{OMP_DISPLAY_AFFINITY} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 6.14 |
| @end table |
| |
| |
| |
| @node OMP_CANCELLATION |
| @section @env{OMP_CANCELLATION} -- Set whether cancellation is activated |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{cancel-var} |
| @item @emph{Scope:} global |
| @item @emph{Description}: |
| If set to @code{TRUE}, the cancellation is activated. If set to @code{FALSE} or |
| if unset, cancellation is disabled and the @code{cancel} construct is ignored. |
| |
| @item @emph{See also}: |
| @ref{omp_get_cancellation} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.11 |
| @end table |
| |
| |
| |
| @node OMP_DISPLAY_AFFINITY |
| @section @env{OMP_DISPLAY_AFFINITY} -- Display thread affinity information |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{display-affinity-var} |
| @item @emph{Scope:} global |
| @item @emph{Description}: |
| If set to @code{FALSE} or if unset, affinity displaying is disabled. |
| If set to @code{TRUE}, the runtime displays affinity information about |
| OpenMP threads in a parallel region upon entering the region and every time |
| any change occurs. |
| |
| @item @emph{See also}: |
| @ref{OMP_AFFINITY_FORMAT} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 6.13 |
| @end table |
| |
| |
| |
| |
| @node OMP_DISPLAY_ENV |
| @section @env{OMP_DISPLAY_ENV} -- Show OpenMP version and environment variables |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} none |
| @item @emph{Scope:} not applicable |
| @item @emph{Description}: |
| If set to @code{TRUE}, the OpenMP version number and the values |
| associated with the OpenMP environment variables are printed to @code{stderr}. |
| If set to @code{VERBOSE}, it additionally shows the value of the environment |
| variables which are GNU extensions. If undefined or set to @code{FALSE}, |
| this information is not shown. |
| |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.12 |
| @end table |
| |
| |
| |
| @node OMP_DEFAULT_DEVICE |
| @section @env{OMP_DEFAULT_DEVICE} -- Set the device used in target regions |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{default-device-var} |
| @item @emph{Scope:} data environment |
| @item @emph{Description}: |
| Set to choose the device which is used in a @code{target} region, unless the |
| value is overridden by @code{omp_set_default_device} or by a @code{device} |
| clause. The value shall be the nonnegative device number. If no device with |
| the given device number exists, the code is executed on the host. If unset, |
| @env{OMP_TARGET_OFFLOAD} is @code{mandatory} and no non-host devices are |
| available, it is set to @code{omp_invalid_device}. Otherwise, if unset, |
| device number 0 is used. |
| |
| |
| @item @emph{See also}: |
| @ref{omp_get_default_device}, @ref{omp_set_default_device}, |
| @ref{OMP_TARGET_OFFLOAD} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.2}, Section 21.2.7 |
| @end table |
| |
| |
| |
| @node OMP_DYNAMIC |
| @section @env{OMP_DYNAMIC} -- Dynamic adjustment of threads |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{dyn-var} |
| @item @emph{Scope:} global |
| @item @emph{Description}: |
| Enable or disable the dynamic adjustment of the number of threads |
| within a team. The value of this environment variable shall be |
| @code{TRUE} or @code{FALSE}. If undefined, dynamic adjustment is |
| disabled by default. |
| |
| @item @emph{See also}: |
| @ref{omp_set_dynamic} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.3 |
| @end table |
| |
| |
| |
| @node OMP_MAX_ACTIVE_LEVELS |
| @section @env{OMP_MAX_ACTIVE_LEVELS} -- Set the maximum number of nested parallel regions |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{max-active-levels-var} |
| @item @emph{Scope:} data environment |
| @item @emph{Description}: |
| Specifies the initial value for the maximum number of nested parallel |
| regions. The value of this variable shall be a positive integer. |
| If undefined, then if @env{OMP_NESTED} is defined and set to true, or |
| if @env{OMP_NUM_THREADS} or @env{OMP_PROC_BIND} are defined and set to |
| a list with more than one item, the maximum number of nested parallel |
| regions is initialized to the largest number supported, otherwise |
| it is set to one. |
| |
| @item @emph{See also}: |
| @ref{omp_set_max_active_levels}, @ref{OMP_NESTED}, @ref{OMP_PROC_BIND}, |
| @ref{OMP_NUM_THREADS} |
| |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.9 |
| @end table |
| |
| |
| |
| @node OMP_MAX_TASK_PRIORITY |
| @section @env{OMP_MAX_TASK_PRIORITY} -- Set the maximum priority |
| number that can be set for a task. |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{max-task-priority-var} |
| @item @emph{Scope:} global |
| @item @emph{Description}: |
| Specifies the initial value for the maximum priority value that can be |
| set for a task. The value of this variable shall be a non-negative |
| integer, and zero is allowed. If undefined, the default priority is |
| 0. |
| |
| @item @emph{See also}: |
| @ref{omp_get_max_task_priority} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.14 |
| @end table |
| |
| |
| |
| @node OMP_NESTED |
| @section @env{OMP_NESTED} -- Nested parallel regions |
| @cindex Environment Variable |
| @cindex Implementation specific setting |
| @table @asis |
| @item @emph{ICV:} @var{max-active-levels-var} |
| @item @emph{Scope:} data environment |
| @item @emph{Description}: |
| Enable or disable nested parallel regions, i.e., whether team members |
| are allowed to create new teams. The value of this environment variable |
| shall be @code{TRUE} or @code{FALSE}. If set to @code{TRUE}, the number |
| of maximum active nested regions supported is by default set to the |
| maximum supported, otherwise it is set to one. If |
| @env{OMP_MAX_ACTIVE_LEVELS} is defined, its setting overrides this |
| setting. If both are undefined, nested parallel regions are enabled if |
| @env{OMP_NUM_THREADS} or @env{OMP_PROC_BINDS} are defined to a list with |
| more than one item, otherwise they are disabled by default. |
| |
| Note that the @code{OMP_NESTED} environment variable was deprecated in |
| the OpenMP specification 5.2 in favor of @code{OMP_MAX_ACTIVE_LEVELS}. |
| |
| @item @emph{See also}: |
| @ref{omp_set_max_active_levels}, @ref{omp_set_nested}, |
| @ref{OMP_MAX_ACTIVE_LEVELS} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.6 |
| @end table |
| |
| |
| |
| @node OMP_NUM_TEAMS |
| @section @env{OMP_NUM_TEAMS} -- Specifies the number of teams to use by teams region |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{nteams-var} |
| @item @emph{Scope:} device |
| @item @emph{Description}: |
| Specifies the upper bound for number of teams to use in teams regions |
| without explicit @code{num_teams} clause. The value of this variable shall |
| be a positive integer. If undefined it defaults to 0 which means |
| implementation defined upper bound. |
| |
| @item @emph{See also}: |
| @ref{omp_set_num_teams} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 6.23 |
| @end table |
| |
| |
| |
| @node OMP_NUM_THREADS |
| @section @env{OMP_NUM_THREADS} -- Specifies the number of threads to use |
| @cindex Environment Variable |
| @cindex Implementation specific setting |
| @table @asis |
| @item @emph{ICV:} @var{nthreads-var} |
| @item @emph{Scope:} data environment |
| @item @emph{Description}: |
| Specifies the default number of threads to use in parallel regions. The |
| value of this variable shall be a comma-separated list of positive integers; |
| the value specifies the number of threads to use for the corresponding nested |
| level. Specifying more than one item in the list automatically enables |
| nesting by default. If undefined one thread per CPU is used. |
| |
| When a list with more than value is specified, it also affects the |
| @var{max-active-levels-var} ICV as described in @ref{OMP_MAX_ACTIVE_LEVELS}. |
| |
| @item @emph{See also}: |
| @ref{omp_set_num_threads}, @ref{OMP_MAX_ACTIVE_LEVELS} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.2 |
| @end table |
| |
| |
| |
| @node OMP_PROC_BIND |
| @section @env{OMP_PROC_BIND} -- Whether threads may be moved between CPUs |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{bind-var} |
| @item @emph{Scope:} data environment |
| @item @emph{Description}: |
| Specifies whether threads may be moved between processors. If set to |
| @code{TRUE}, OpenMP threads should not be moved; if set to @code{FALSE} |
| they may be moved. Alternatively, a comma separated list with the |
| values @code{PRIMARY}, @code{MASTER}, @code{CLOSE} and @code{SPREAD} can |
| be used to specify the thread affinity policy for the corresponding nesting |
| level. With @code{PRIMARY} and @code{MASTER} the worker threads are in the |
| same place partition as the primary thread. With @code{CLOSE} those are |
| kept close to the primary thread in contiguous place partitions. And |
| with @code{SPREAD} a sparse distribution |
| across the place partitions is used. Specifying more than one item in the |
| list automatically enables nesting by default. |
| |
| When a list is specified, it also affects the @var{max-active-levels-var} ICV |
| as described in @ref{OMP_MAX_ACTIVE_LEVELS}. |
| |
| When undefined, @env{OMP_PROC_BIND} defaults to @code{TRUE} when |
| @env{OMP_PLACES} or @env{GOMP_CPU_AFFINITY} is set and @code{FALSE} otherwise. |
| |
| @item @emph{See also}: |
| @ref{omp_get_proc_bind}, @ref{GOMP_CPU_AFFINITY}, @ref{OMP_PLACES}, |
| @ref{OMP_MAX_ACTIVE_LEVELS} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.4 |
| @end table |
| |
| |
| |
| @node OMP_PLACES |
| @section @env{OMP_PLACES} -- Specifies on which CPUs the threads should be placed |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{place-partition-var} |
| @item @emph{Scope:} implicit tasks |
| @item @emph{Description}: |
| The thread placement can be either specified using an abstract name or by an |
| explicit list of the places. The abstract names @code{threads}, @code{cores}, |
| @code{sockets}, @code{ll_caches} and @code{numa_domains} can be optionally |
| followed by a positive number in parentheses, which denotes the how many places |
| shall be created. With @code{threads} each place corresponds to a single |
| hardware thread; @code{cores} to a single core with the corresponding number of |
| hardware threads; with @code{sockets} the place corresponds to a single |
| socket; with @code{ll_caches} to a set of cores that shares the last level |
| cache on the device; and @code{numa_domains} to a set of cores for which their |
| closest memory on the device is the same memory and at a similar distance from |
| the cores. The resulting placement can be shown by setting the |
| @env{OMP_DISPLAY_ENV} environment variable. |
| |
| Alternatively, the placement can be specified explicitly as comma-separated |
| list of places. A place is specified by set of nonnegative numbers in curly |
| braces, denoting the hardware threads. The curly braces can be omitted |
| when only a single number has been specified. The hardware threads |
| belonging to a place can either be specified as comma-separated list of |
| nonnegative thread numbers or using an interval. Multiple places can also be |
| either specified by a comma-separated list of places or by an interval. To |
| specify an interval, a colon followed by the count is placed after |
| the hardware thread number or the place. Optionally, the length can be |
| followed by a colon and the stride number -- otherwise a unit stride is |
| assumed. Placing an exclamation mark (@code{!}) directly before a curly |
| brace or numbers inside the curly braces (excluding intervals) |
| excludes those hardware threads. |
| |
| For instance, the following specifies the same places list: |
| @code{"@{0,1,2@}, @{3,4,6@}, @{7,8,9@}, @{10,11,12@}"}; |
| @code{"@{0:3@}, @{3:3@}, @{7:3@}, @{10:3@}"}; and @code{"@{0:2@}:4:3"}. |
| |
| If @env{OMP_PLACES} and @env{GOMP_CPU_AFFINITY} are unset and |
| @env{OMP_PROC_BIND} is either unset or @code{false}, threads may be moved |
| between CPUs following no placement policy. |
| |
| @item @emph{See also}: |
| @ref{OMP_PROC_BIND}, @ref{GOMP_CPU_AFFINITY}, @ref{omp_get_proc_bind}, |
| @ref{OMP_DISPLAY_ENV} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.5 |
| @end table |
| |
| |
| |
| @node OMP_STACKSIZE |
| @section @env{OMP_STACKSIZE} -- Set default thread stack size |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{stacksize-var} |
| @item @emph{Scope:} device |
| @item @emph{Description}: |
| Set the default thread stack size in kilobytes, unless the number |
| is suffixed by @code{B}, @code{K}, @code{M} or @code{G}, in which |
| case the size is, respectively, in bytes, kilobytes, megabytes |
| or gigabytes. This is different from @code{pthread_attr_setstacksize} |
| which gets the number of bytes as an argument. If the stack size cannot |
| be set due to system constraints, an error is reported and the initial |
| stack size is left unchanged. If undefined, the stack size is system |
| dependent. |
| |
| @item @emph{See also}: |
| @ref{GOMP_STACKSIZE} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.7 |
| @end table |
| |
| |
| |
| @node OMP_SCHEDULE |
| @section @env{OMP_SCHEDULE} -- How threads are scheduled |
| @cindex Environment Variable |
| @cindex Implementation specific setting |
| @table @asis |
| @item @emph{ICV:} @var{run-sched-var} |
| @item @emph{Scope:} data environment |
| @item @emph{Description}: |
| Allows to specify @code{schedule type} and @code{chunk size}. |
| The value of the variable shall have the form: @code{type[,chunk]} where |
| @code{type} is one of @code{static}, @code{dynamic}, @code{guided} or @code{auto} |
| The optional @code{chunk} size shall be a positive integer. If undefined, |
| dynamic scheduling and a chunk size of 1 is used. |
| |
| @item @emph{See also}: |
| @ref{omp_set_schedule} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Sections 2.7.1.1 and 4.1 |
| @end table |
| |
| |
| |
| @node OMP_TARGET_OFFLOAD |
| @section @env{OMP_TARGET_OFFLOAD} -- Controls offloading behavior |
| @cindex Environment Variable |
| @cindex Implementation specific setting |
| @table @asis |
| @item @emph{ICV:} @var{target-offload-var} |
| @item @emph{Scope:} global |
| @item @emph{Description}: |
| Specifies the behavior with regard to offloading code to a device. This |
| variable can be set to one of three values - @code{MANDATORY}, @code{DISABLED} |
| or @code{DEFAULT}. |
| |
| If set to @code{MANDATORY}, the program terminates with an error if |
| any device construct or device memory routine uses a device that is unavailable |
| or not supported by the implementation, or uses a non-conforming device number. |
| If set to @code{DISABLED}, then offloading is disabled and all code runs on |
| the host. If set to @code{DEFAULT}, the program tries offloading to the |
| device first, then falls back to running code on the host if it cannot. |
| |
| If undefined, then the program behaves as if @code{DEFAULT} was set. |
| |
| Note: Even with @code{MANDATORY}, no run-time termination is performed when |
| the device number in a @code{device} clause or argument to a device memory |
| routine is for host, which includes using the device number in the |
| @var{default-device-var} ICV. However, the initial value of |
| the @var{default-device-var} ICV is affected by @code{MANDATORY}. |
| |
| @item @emph{See also}: |
| @ref{OMP_DEFAULT_DEVICE} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.2}, Section 21.2.8 |
| @end table |
| |
| |
| |
| @node OMP_TEAMS_THREAD_LIMIT |
| @section @env{OMP_TEAMS_THREAD_LIMIT} -- Set the maximum number of threads imposed by teams |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{teams-thread-limit-var} |
| @item @emph{Scope:} device |
| @item @emph{Description}: |
| Specifies an upper bound for the number of threads to use by each contention |
| group created by a teams construct without explicit @code{thread_limit} |
| clause. The value of this variable shall be a positive integer. If undefined, |
| the value of 0 is used which stands for an implementation defined upper |
| limit. |
| |
| @item @emph{See also}: |
| @ref{OMP_THREAD_LIMIT}, @ref{omp_set_teams_thread_limit} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 6.24 |
| @end table |
| |
| |
| |
| @node OMP_THREAD_LIMIT |
| @section @env{OMP_THREAD_LIMIT} -- Set the maximum number of threads |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{ICV:} @var{thread-limit-var} |
| @item @emph{Scope:} data environment |
| @item @emph{Description}: |
| Specifies the number of threads to use for the whole program. The |
| value of this variable shall be a positive integer. If undefined, |
| the number of threads is not limited. |
| |
| @item @emph{See also}: |
| @ref{OMP_NUM_THREADS}, @ref{omp_get_thread_limit} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.10 |
| @end table |
| |
| |
| |
| @node OMP_WAIT_POLICY |
| @section @env{OMP_WAIT_POLICY} -- How waiting threads are handled |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{Description}: |
| Specifies whether waiting threads should be active or passive. If |
| the value is @code{PASSIVE}, waiting threads should not consume CPU |
| power while waiting; while the value is @code{ACTIVE} specifies that |
| they should. If undefined, threads wait actively for a short time |
| before waiting passively. |
| |
| @item @emph{See also}: |
| @ref{GOMP_SPINCOUNT} |
| |
| @item @emph{Reference}: |
| @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.8 |
| @end table |
| |
| |
| |
| @node GOMP_CPU_AFFINITY |
| @section @env{GOMP_CPU_AFFINITY} -- Bind threads to specific CPUs |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{Description}: |
| Binds threads to specific CPUs. The variable should contain a space-separated |
| or comma-separated list of CPUs. This list may contain different kinds of |
| entries: either single CPU numbers in any order, a range of CPUs (M-N) |
| or a range with some stride (M-N:S). CPU numbers are zero based. For example, |
| @code{GOMP_CPU_AFFINITY="0 3 1-2 4-15:2"} binds the initial thread |
| to CPU 0, the second to CPU 3, the third to CPU 1, the fourth to |
| CPU 2, the fifth to CPU 4, the sixth through tenth to CPUs 6, 8, 10, 12, |
| and 14 respectively and then starts assigning back from the beginning of |
| the list. @code{GOMP_CPU_AFFINITY=0} binds all threads to CPU 0. |
| |
| There is no libgomp library routine to determine whether a CPU affinity |
| specification is in effect. As a workaround, language-specific library |
| functions, e.g., @code{getenv} in C or @code{GET_ENVIRONMENT_VARIABLE} in |
| Fortran, may be used to query the setting of the @code{GOMP_CPU_AFFINITY} |
| environment variable. A defined CPU affinity on startup cannot be changed |
| or disabled during the runtime of the application. |
| |
| If both @env{GOMP_CPU_AFFINITY} and @env{OMP_PROC_BIND} are set, |
| @env{OMP_PROC_BIND} has a higher precedence. If neither has been set and |
| @env{OMP_PROC_BIND} is unset, or when @env{OMP_PROC_BIND} is set to |
| @code{FALSE}, the host system handles the assignment of threads to CPUs. |
| |
| @item @emph{See also}: |
| @ref{OMP_PLACES}, @ref{OMP_PROC_BIND} |
| @end table |
| |
| |
| |
| @node GOMP_DEBUG |
| @section @env{GOMP_DEBUG} -- Enable debugging output |
| @cindex Environment Variable |
| @table @asis |
| @item @emph{Description}: |
| Enable debugging output. The variable should be set to @code{0} |
| (disabled, also the default if not set), or @code{1} (enabled). |
| |
| If enabled, some debugging output is printed during execution. |
| This is currently not specified in more detail, and subject to change. |
| @end table |
| |
| |
| |
| @node GOMP_STACKSIZE |
| @section @env{GOMP_STACKSIZE} -- Set default thread stack size |
| @cindex Environment Variable |
| @cindex Implementation specific setting |
| @table @asis |
| @item @emph{Description}: |
| Set the default thread stack size in kilobytes. This is different from |
| @code{pthread_attr_setstacksize} which gets the number of bytes as an |
| argument. If the stack size cannot be set due to system constraints, an |
| error is reported and the initial stack size is left unchanged. If undefined, |
| the stack size is system dependent. |
| |
| @item @emph{See also}: |
| @ref{OMP_STACKSIZE} |
| |
| @item @emph{Reference}: |
| @uref{https://gcc.gnu.org/ml/gcc-patches/2006-06/msg00493.html, |
| GCC Patches Mailinglist}, |
| @uref{https://gcc.gnu.org/ml/gcc-patches/2006-06/msg00496.html, |
| GCC Patches Mailinglist} |
| @end table |
| |
| |
| |
| @node GOMP_SPINCOUNT |
| @section @env{GOMP_SPINCOUNT} -- Set the busy-wait spin count |
| @cindex Environment Variable |
| @cindex Implementation specific setting |
| @table @asis |
| @item @emph{Description}: |
| Determines how long a threads waits actively with consuming CPU power |
| before waiting passively without consuming CPU power. The value may be |
| either @code{INFINITE}, @code{INFINITY} to always wait actively or an |
| integer which gives the number of spins of the busy-wait loop. The |
| integer may optionally be followed by the following suffixes acting |
| as multiplication factors: @code{k} (kilo, thousand), @code{M} (mega, |
| million), @code{G} (giga, billion), or @code{T} (tera, trillion). |
| If undefined, 0 is used when @env{OMP_WAIT_POLICY} is @code{PASSIVE}, |
| 300,000 is used when @env{OMP_WAIT_POLICY} is undefined and |
| 30 billion is used when @env{OMP_WAIT_POLICY} is @code{ACTIVE}. |
| If there are more OpenMP threads than available CPUs, 1000 and 100 |
| spins are used for @env{OMP_WAIT_POLICY} being @code{ACTIVE} or |
| undefined, respectively; unless the @env{GOMP_SPINCOUNT} is lower |
| or @env{OMP_WAIT_POLICY} is @code{PASSIVE}. |
| |
| @item @emph{See also}: |
| @ref{OMP_WAIT_POLICY} |
| @end table |
| |
| |
| |
| @node GOMP_RTEMS_THREAD_POOLS |
| @section @env{GOMP_RTEMS_THREAD_POOLS} -- Set the RTEMS specific thread pools |
| @cindex Environment Variable |
| @cindex Implementation specific setting |
| @table @asis |
| @item @emph{Description}: |
| This environment variable is only used on the RTEMS real-time operating system. |
| It determines the scheduler instance specific thread pools. The format for |
| @env{GOMP_RTEMS_THREAD_POOLS} is a list of optional |
| @code{<thread-pool-count>[$<priority>]@@<scheduler-name>} configurations |
| separated by @code{:} where: |
| @itemize @bullet |
| @item @code{<thread-pool-count>} is the thread pool count for this scheduler |
| instance. |
| @item @code{$<priority>} is an optional priority for the worker threads of a |
| thread pool according to @code{pthread_setschedparam}. In case a priority |
| value is omitted, then a worker thread inherits the priority of the OpenMP |
| primary thread that created it. The priority of the worker thread is not |
| changed after creation, even if a new OpenMP primary thread using the worker has |
| a different priority. |
| @item @code{@@<scheduler-name>} is the scheduler instance name according to the |
| RTEMS application configuration. |
| @end itemize |
| In case no thread pool configuration is specified for a scheduler instance, |
| then each OpenMP primary thread of this scheduler instance uses its own |
| dynamically allocated thread pool. To limit the worker thread count of the |
| thread pools, each OpenMP primary thread must call @code{omp_set_num_threads}. |
| @item @emph{Example}: |
| Lets suppose we have three scheduler instances @code{IO}, @code{WRK0}, and |
| @code{WRK1} with @env{GOMP_RTEMS_THREAD_POOLS} set to |
| @code{"1@@WRK0:3$4@@WRK1"}. Then there are no thread pool restrictions for |
| scheduler instance @code{IO}. In the scheduler instance @code{WRK0} there is |
| one thread pool available. Since no priority is specified for this scheduler |
| instance, the worker thread inherits the priority of the OpenMP primary thread |
| that created it. In the scheduler instance @code{WRK1} there are three thread |
| pools available and their worker threads run at priority four. |
| @end table |
| |
| |
| |
| @c --------------------------------------------------------------------- |
| @c Enabling OpenACC |
| @c --------------------------------------------------------------------- |
| |
| @node Enabling OpenACC |
| @chapter Enabling OpenACC |
| |
| To activate the OpenACC extensions for C/C++ and Fortran, the compile-time |
| flag @option{-fopenacc} must be specified. This enables the OpenACC directive |
| @samp{#pragma acc} in C/C++ and, in Fortran, the @samp{!$acc} sentinel in free |
| source form and the @samp{c$acc}, @samp{*$acc} and @samp{!$acc} sentinels in |
| fixed source form. The flag also arranges for automatic linking of the OpenACC |
| runtime library (@ref{OpenACC Runtime Library Routines}). |
| |
| See @uref{https://gcc.gnu.org/wiki/OpenACC} for more information. |
| |
| A complete description of all OpenACC directives accepted may be found in |
| the @uref{https://www.openacc.org, OpenACC} Application Programming |
| Interface manual, version 2.6. |
| |
| |
| |
| @c --------------------------------------------------------------------- |
| @c OpenACC Runtime Library Routines |
| @c --------------------------------------------------------------------- |
| |
| @node OpenACC Runtime Library Routines |
| @chapter OpenACC Runtime Library Routines |
| |
| The runtime routines described here are defined by section 3 of the OpenACC |
| specifications in version 2.6. |
| They have C linkage, and do not throw exceptions. |
| Generally, they are available only for the host, with the exception of |
| @code{acc_on_device}, which is available for both the host and the |
| acceleration device. |
| |
| @menu |
| * acc_get_num_devices:: Get number of devices for the given device |
| type. |
| * acc_set_device_type:: Set type of device accelerator to use. |
| * acc_get_device_type:: Get type of device accelerator to be used. |
| * acc_set_device_num:: Set device number to use. |
| * acc_get_device_num:: Get device number to be used. |
| * acc_get_property:: Get device property. |
| * acc_async_test:: Tests for completion of a specific asynchronous |
| operation. |
| * acc_async_test_all:: Tests for completion of all asynchronous |
| operations. |
| * acc_wait:: Wait for completion of a specific asynchronous |
| operation. |
| * acc_wait_all:: Waits for completion of all asynchronous |
| operations. |
| * acc_wait_all_async:: Wait for completion of all asynchronous |
| operations. |
| * acc_wait_async:: Wait for completion of asynchronous operations. |
| * acc_init:: Initialize runtime for a specific device type. |
| * acc_shutdown:: Shuts down the runtime for a specific device |
| type. |
| * acc_on_device:: Whether executing on a particular device |
| * acc_malloc:: Allocate device memory. |
| * acc_free:: Free device memory. |
| * acc_copyin:: Allocate device memory and copy host memory to |
| it. |
| * acc_present_or_copyin:: If the data is not present on the device, |
| allocate device memory and copy from host |
| memory. |
| * acc_create:: Allocate device memory and map it to host |
| memory. |
| * acc_present_or_create:: If the data is not present on the device, |
| allocate device memory and map it to host |
| memory. |
| * acc_copyout:: Copy device memory to host memory. |
| * acc_delete:: Free device memory. |
| * acc_update_device:: Update device memory from mapped host memory. |
| * acc_update_self:: Update host memory from mapped device memory. |
| * acc_map_data:: Map previously allocated device memory to host |
| memory. |
| * acc_unmap_data:: Unmap device memory from host memory. |
| * acc_deviceptr:: Get device pointer associated with specific |
| host address. |
| * acc_hostptr:: Get host pointer associated with specific |
| device address. |
| * acc_is_present:: Indicate whether host variable / array is |
| present on device. |
| * acc_memcpy_to_device:: Copy host memory to device memory. |
| * acc_memcpy_from_device:: Copy device memory to host memory. |
| * acc_attach:: Let device pointer point to device-pointer target. |
| * acc_detach:: Let device pointer point to host-pointer target. |
| |
| API routines for target platforms. |
| |
| * acc_get_current_cuda_device:: Get CUDA device handle. |
| * acc_get_current_cuda_context::Get CUDA context handle. |
| * acc_get_cuda_stream:: Get CUDA stream handle. |
| * acc_set_cuda_stream:: Set CUDA stream handle. |
| |
| API routines for the OpenACC Profiling Interface. |
| |
| * acc_prof_register:: Register callbacks. |
| * acc_prof_unregister:: Unregister callbacks. |
| * acc_prof_lookup:: Obtain inquiry functions. |
| * acc_register_library:: Library registration. |
| @end menu |
| |
| |
| |
| @node acc_get_num_devices |
| @section @code{acc_get_num_devices} -- Get number of devices for given device type |
| @table @asis |
| @item @emph{Description} |
| This function returns a value indicating the number of devices available |
| for the device type specified in @var{devicetype}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int acc_get_num_devices(acc_device_t devicetype);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{integer function acc_get_num_devices(devicetype)} |
| @item @tab @code{integer(kind=acc_device_kind) devicetype} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.1. |
| @end table |
| |
| |
| |
| @node acc_set_device_type |
| @section @code{acc_set_device_type} -- Set type of device accelerator to use. |
| @table @asis |
| @item @emph{Description} |
| This function indicates to the runtime library which device type, specified |
| in @var{devicetype}, to use when executing a parallel or kernels region. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{acc_set_device_type(acc_device_t devicetype);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine acc_set_device_type(devicetype)} |
| @item @tab @code{integer(kind=acc_device_kind) devicetype} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.2. |
| @end table |
| |
| |
| |
| @node acc_get_device_type |
| @section @code{acc_get_device_type} -- Get type of device accelerator to be used. |
| @table @asis |
| @item @emph{Description} |
| This function returns what device type will be used when executing a |
| parallel or kernels region. |
| |
| This function returns @code{acc_device_none} if |
| @code{acc_get_device_type} is called from |
| @code{acc_ev_device_init_start}, @code{acc_ev_device_init_end} |
| callbacks of the OpenACC Profiling Interface (@ref{OpenACC Profiling |
| Interface}), that is, if the device is currently being initialized. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{acc_device_t acc_get_device_type(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{function acc_get_device_type(void)} |
| @item @tab @code{integer(kind=acc_device_kind) acc_get_device_type} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.3. |
| @end table |
| |
| |
| |
| @node acc_set_device_num |
| @section @code{acc_set_device_num} -- Set device number to use. |
| @table @asis |
| @item @emph{Description} |
| This function will indicate to the runtime which device number, |
| specified by @var{devicenum}, associated with the specified device |
| type @var{devicetype}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{acc_set_device_num(int devicenum, acc_device_t devicetype);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine acc_set_device_num(devicenum, devicetype)} |
| @item @tab @code{integer devicenum} |
| @item @tab @code{integer(kind=acc_device_kind) devicetype} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.4. |
| @end table |
| |
| |
| |
| @node acc_get_device_num |
| @section @code{acc_get_device_num} -- Get device number to be used. |
| @table @asis |
| @item @emph{Description} |
| This function returns which device number associated with the specified device |
| type @var{devicetype}, will be used when executing a parallel or kernels |
| region. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int acc_get_device_num(acc_device_t devicetype);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{function acc_get_device_num(devicetype)} |
| @item @tab @code{integer(kind=acc_device_kind) devicetype} |
| @item @tab @code{integer acc_get_device_num} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.5. |
| @end table |
| |
| |
| |
| @node acc_get_property |
| @section @code{acc_get_property} -- Get device property. |
| @cindex acc_get_property |
| @cindex acc_get_property_string |
| @table @asis |
| @item @emph{Description} |
| These routines return the value of the specified @var{property} for the |
| device being queried according to @var{devicenum} and @var{devicetype}. |
| Integer-valued and string-valued properties are returned by |
| @code{acc_get_property} and @code{acc_get_property_string} respectively. |
| The Fortran @code{acc_get_property_string} subroutine returns the string |
| retrieved in its fourth argument while the remaining entry points are |
| functions, which pass the return value as their result. |
| |
| Note for Fortran, only: the OpenACC technical committee corrected and, hence, |
| modified the interface introduced in OpenACC 2.6. The kind-value parameter |
| @code{acc_device_property} has been renamed to @code{acc_device_property_kind} |
| for consistency and the return type of the @code{acc_get_property} function is |
| now a @code{c_size_t} integer instead of a @code{acc_device_property} integer. |
| The parameter @code{acc_device_property} is still provided, |
| but might be removed in a future version of GCC. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{size_t acc_get_property(int devicenum, acc_device_t devicetype, acc_device_property_t property);} |
| @item @emph{Prototype}: @tab @code{const char *acc_get_property_string(int devicenum, acc_device_t devicetype, acc_device_property_t property);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{function acc_get_property(devicenum, devicetype, property)} |
| @item @emph{Interface}: @tab @code{subroutine acc_get_property_string(devicenum, devicetype, property, string)} |
| @item @tab @code{use ISO_C_Binding, only: c_size_t} |
| @item @tab @code{integer devicenum} |
| @item @tab @code{integer(kind=acc_device_kind) devicetype} |
| @item @tab @code{integer(kind=acc_device_property_kind) property} |
| @item @tab @code{integer(kind=c_size_t) acc_get_property} |
| @item @tab @code{character(*) string} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.6. |
| @end table |
| |
| |
| |
| @node acc_async_test |
| @section @code{acc_async_test} -- Test for completion of a specific asynchronous operation. |
| @table @asis |
| @item @emph{Description} |
| This function tests for completion of the asynchronous operation specified |
| in @var{arg}. In C/C++, a non-zero value is returned to indicate |
| the specified asynchronous operation has completed while Fortran returns |
| @code{true}. If the asynchronous operation has not completed, C/C++ returns |
| zero and Fortran returns @code{false}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int acc_async_test(int arg);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{function acc_async_test(arg)} |
| @item @tab @code{integer(kind=acc_handle_kind) arg} |
| @item @tab @code{logical acc_async_test} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.9. |
| @end table |
| |
| |
| |
| @node acc_async_test_all |
| @section @code{acc_async_test_all} -- Tests for completion of all asynchronous operations. |
| @table @asis |
| @item @emph{Description} |
| This function tests for completion of all asynchronous operations. |
| In C/C++, a non-zero value is returned to indicate all asynchronous |
| operations have completed while Fortran returns @code{true}. If |
| any asynchronous operation has not completed, C/C++ returns zero and |
| Fortran returns @code{false}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{int acc_async_test_all(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{function acc_async_test()} |
| @item @tab @code{logical acc_get_device_num} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.10. |
| @end table |
| |
| |
| |
| @node acc_wait |
| @section @code{acc_wait} -- Wait for completion of a specific asynchronous operation. |
| @table @asis |
| @item @emph{Description} |
| This function waits for completion of the asynchronous operation |
| specified in @var{arg}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{acc_wait(arg);} |
| @item @emph{Prototype (OpenACC 1.0 compatibility)}: @tab @code{acc_async_wait(arg);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine acc_wait(arg)} |
| @item @tab @code{integer(acc_handle_kind) arg} |
| @item @emph{Interface (OpenACC 1.0 compatibility)}: @tab @code{subroutine acc_async_wait(arg)} |
| @item @tab @code{integer(acc_handle_kind) arg} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.11. |
| @end table |
| |
| |
| |
| @node acc_wait_all |
| @section @code{acc_wait_all} -- Waits for completion of all asynchronous operations. |
| @table @asis |
| @item @emph{Description} |
| This function waits for the completion of all asynchronous operations. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{acc_wait_all(void);} |
| @item @emph{Prototype (OpenACC 1.0 compatibility)}: @tab @code{acc_async_wait_all(void);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine acc_wait_all()} |
| @item @emph{Interface (OpenACC 1.0 compatibility)}: @tab @code{subroutine acc_async_wait_all()} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.13. |
| @end table |
| |
| |
| |
| @node acc_wait_all_async |
| @section @code{acc_wait_all_async} -- Wait for completion of all asynchronous operations. |
| @table @asis |
| @item @emph{Description} |
| This function enqueues a wait operation on the queue @var{async} for any |
| and all asynchronous operations that have been previously enqueued on |
| any queue. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{acc_wait_all_async(int async);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine acc_wait_all_async(async)} |
| @item @tab @code{integer(acc_handle_kind) async} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.14. |
| @end table |
| |
| |
| |
| @node acc_wait_async |
| @section @code{acc_wait_async} -- Wait for completion of asynchronous operations. |
| @table @asis |
| @item @emph{Description} |
| This function enqueues a wait operation on queue @var{async} for any and all |
| asynchronous operations enqueued on queue @var{arg}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{acc_wait_async(int arg, int async);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine acc_wait_async(arg, async)} |
| @item @tab @code{integer(acc_handle_kind) arg, async} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.12. |
| @end table |
| |
| |
| |
| @node acc_init |
| @section @code{acc_init} -- Initialize runtime for a specific device type. |
| @table @asis |
| @item @emph{Description} |
| This function initializes the runtime for the device type specified in |
| @var{devicetype}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{acc_init(acc_device_t devicetype);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine acc_init(devicetype)} |
| @item @tab @code{integer(acc_device_kind) devicetype} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.7. |
| @end table |
| |
| |
| |
| @node acc_shutdown |
| @section @code{acc_shutdown} -- Shuts down the runtime for a specific device type. |
| @table @asis |
| @item @emph{Description} |
| This function shuts down the runtime for the device type specified in |
| @var{devicetype}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{acc_shutdown(acc_device_t devicetype);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{subroutine acc_shutdown(devicetype)} |
| @item @tab @code{integer(acc_device_kind) devicetype} |
| @end multitable |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.8. |
| @end table |
| |
| |
| |
| @node acc_on_device |
| @section @code{acc_on_device} -- Whether executing on a particular device |
| @table @asis |
| @item @emph{Description}: |
| This function returns whether the program is executing on a particular |
| device specified in @var{devicetype}. In C/C++ a non-zero value is |
| returned to indicate the device is executing on the specified device type. |
| In Fortran, @code{true} is returned. If the program is not executing |
| on the specified device type C/C++ returns zero, while Fortran |
| returns @code{false}. |
| |
| @item @emph{C/C++}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Prototype}: @tab @code{acc_on_device(acc_device_t devicetype);} |
| @end multitable |
| |
| @item @emph{Fortran}: |
| @multitable @columnfractions .20 .80 |
| @item @emph{Interface}: @tab @code{function acc_on_device(devicetype)} |
| @item @tab @code{integer(acc_device_kind) devicetype} |
| @item @tab @code{logical acc_on_device} |
| @end multitable |
| |
| |
| @item @emph{Reference}: |
| @uref{https://www.openacc.org, OpenACC specification v2.6}, section |
| 3.2.17. |
| @end table |
| |
|
