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| author | Jonathan Peyton <jonathan.l.peyton@intel.com> | 2017-06-13 17:16:12 +0000 |
|---|---|---|
| committer | Jonathan Peyton <jonathan.l.peyton@intel.com> | 2017-06-13 17:16:12 +0000 |
| commit | d330e630dbf0a29179b594a287d16cab77e5941d (patch) | |
| tree | 61447a57f1d330cd8044e3a1fce8155cebd6debe /openmp | |
| parent | b3a8d20e27b41be00e1876c606d43c5794815e0b (diff) | |
| download | llvm-d330e630dbf0a29179b594a287d16cab77e5941d.zip llvm-d330e630dbf0a29179b594a287d16cab77e5941d.tar.gz llvm-d330e630dbf0a29179b594a287d16cab77e5941d.tar.bz2 | |
Reset initial affinity in children processes
If OpenMP is initialized before fork()-ing occurs and affinity is set to
something like compact, then the master thread will be pinned to a single HW
thread/core after initialization. If the master (or any other thread) then
forks N processes, all N processes will then be pinned to that same single HW
thread/core. To reset the affinity for the new child process, the atfork
handler for the child process can call kmp_set_thread_affinity_mask_initial()
to reset its affinity to the initial affinity of the application before it
re-initializes libomp. The parent process will not be affected and still
keeps its affinity setting.
Differential Revision: https://reviews.llvm.org/D34118
llvm-svn: 305306
Diffstat (limited to 'openmp')
| -rw-r--r-- | openmp/runtime/src/kmp.h | 3 | ||||
| -rw-r--r-- | openmp/runtime/src/z_Linux_util.cpp | 6 |
2 files changed, 9 insertions, 0 deletions
diff --git a/openmp/runtime/src/kmp.h b/openmp/runtime/src/kmp.h index cab0d04..f2f0cdc 100644 --- a/openmp/runtime/src/kmp.h +++ b/openmp/runtime/src/kmp.h @@ -3268,6 +3268,9 @@ extern int __kmp_aux_set_affinity_mask_proc(int proc, void **mask); extern int __kmp_aux_unset_affinity_mask_proc(int proc, void **mask); extern int __kmp_aux_get_affinity_mask_proc(int proc, void **mask); extern void __kmp_balanced_affinity(int tid, int team_size); +#if KMP_OS_LINUX +extern int kmp_set_thread_affinity_mask_initial(void); +#endif #endif /* KMP_AFFINITY_SUPPORTED */ extern void __kmp_cleanup_hierarchy(); diff --git a/openmp/runtime/src/z_Linux_util.cpp b/openmp/runtime/src/z_Linux_util.cpp index 2f83c02..a0d1639 100644 --- a/openmp/runtime/src/z_Linux_util.cpp +++ b/openmp/runtime/src/z_Linux_util.cpp @@ -1280,6 +1280,12 @@ static void __kmp_atfork_child(void) { ++__kmp_fork_count; +#if KMP_AFFINITY_SUPPORTED && KMP_OS_LINUX + // reset the affinity in the child to the initial thread + // affinity in the parent + kmp_set_thread_affinity_mask_initial(); +#endif + __kmp_init_runtime = FALSE; #if KMP_USE_MONITOR __kmp_init_monitor = 0; |