Merge commit 73bb8d9d92f6 from llvm-project (by Jonathan Peyton):

  [OpenMP] Fix child processes to use affinity_none (#91391)

  When a child process is forked with OpenMP already initialized, the
  child process resets its affinity mask and sets proc-bind-var to false
  so that the entire original affinity mask is used. This patch corrects
  an issue with the affinity initialization code setting affinity to
  compact instead of none for this special case of forked children.

  The test trying to catch this only testing explicit setting of
  KMP_AFFINITY=none. Add test run for no KMP_AFFINITY setting.

  Fixes: #91098

This should fix OpenMP processes sometimes getting stuck on a single CPU
core.

PR:		278845
Reported by:	Cassidy B. Larson <cbl@cbl.us>
MFC after:	3 days

1 files changed, 2 insertions, 0 deletions

diff --git a/contrib/llvm-project/openmp/runtime/src/kmp_settings.cpp b/contrib/llvm-project/openmp/runtime/src/kmp_settings.cpp
index ec86ee07472c..58f19ea5b8ab 100644
--- a/contrib/llvm-project/openmp/runtime/src/kmp_settings.cpp
+++ b/contrib/llvm-project/openmp/runtime/src/kmp_settings.cpp
@@ -6426,6 +6426,8 @@ void __kmp_env_initialize(char const *string) {
         }
         if ((__kmp_nested_proc_bind.bind_types[0] != proc_bind_intel) &&
             (__kmp_nested_proc_bind.bind_types[0] != proc_bind_default)) {
+          if (__kmp_nested_proc_bind.bind_types[0] == proc_bind_false)
+            __kmp_affinity.type = affinity_none;
           if (__kmp_affinity.type == affinity_default) {
             __kmp_affinity.type = affinity_compact;
             __kmp_affinity.flags.dups = FALSE;