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| author | Jonathan Peyton <jonathan.l.peyton@intel.com> | 2017-06-15 21:51:07 +0000 |
|---|---|---|
| committer | Jonathan Peyton <jonathan.l.peyton@intel.com> | 2017-06-15 21:51:07 +0000 |
| commit | 072ccb72396a1b8143ecfe8214e000c542916cc0 (patch) | |
| tree | b879405e206336519e1c55da21dcec40d126ee0d /openmp | |
| parent | 383971d2a7d38607c042660218c4bf7a2443a655 (diff) | |
| download | llvm-072ccb72396a1b8143ecfe8214e000c542916cc0.zip llvm-072ccb72396a1b8143ecfe8214e000c542916cc0.tar.gz llvm-072ccb72396a1b8143ecfe8214e000c542916cc0.tar.bz2 | |
Set affinity to none/false in child processes
Reset affinity to none (false for proc-bind-var) so that threads in the child
processes are not bound tightly, unless the user explicitly sets this in
KMP_AFFINITY/OMP_PROC_BIND, in child processes. This can improve
performance for scripting languages which fork for parallelism like Python's
multiprocessing module.
Differential Revision: https://reviews.llvm.org/D34154
llvm-svn: 305513
Diffstat (limited to 'openmp')
| -rw-r--r-- | openmp/runtime/src/z_Linux_util.cpp | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/openmp/runtime/src/z_Linux_util.cpp b/openmp/runtime/src/z_Linux_util.cpp index a0d1639..914275a 100644 --- a/openmp/runtime/src/z_Linux_util.cpp +++ b/openmp/runtime/src/z_Linux_util.cpp @@ -1280,11 +1280,22 @@ static void __kmp_atfork_child(void) { ++__kmp_fork_count; -#if KMP_AFFINITY_SUPPORTED && KMP_OS_LINUX +#if KMP_AFFINITY_SUPPORTED +#if KMP_OS_LINUX // reset the affinity in the child to the initial thread // affinity in the parent kmp_set_thread_affinity_mask_initial(); #endif + // Set default not to bind threads tightly in the child (we’re expecting + // over-subscription after the fork and this can improve things for + // scripting languages that use OpenMP inside process-parallel code). + __kmp_affinity_type = affinity_none; +#if OMP_40_ENABLED + if (__kmp_nested_proc_bind.bind_types != NULL) { + __kmp_nested_proc_bind.bind_types[0] = proc_bind_false; + } +#endif // OMP_40_ENABLED +#endif // KMP_AFFINITY_SUPPORTED __kmp_init_runtime = FALSE; #if KMP_USE_MONITOR |