OMP_WAIT_POLICY changes

This change has OMP_WAIT_POLICY=active to mean that threads will busy-wait in
spin loops and virtually never go to sleep. OMP_WAIT_POLICY=passive now means
that threads will immediately go to sleep inside a spin loop. KMP_BLOCKTIME was
the previous mechanism to specify this behavior via KMP_BLOCKTIME=0 or
KMP_BLOCKTIME=infinite, but the standard OpenMP environment variable should
also be able to specify this behavior.

Differential Revision: http://reviews.llvm.org/D18577

llvm-svn: 265339

1 files changed, 15 insertions, 2 deletions

diff --git a/openmp/runtime/src/kmp_settings.c b/openmp/runtime/src/kmp_settings.c
index ac53c471cf2..23ed25636d2 100644
--- a/openmp/runtime/src/kmp_settings.c
+++ b/openmp/runtime/src/kmp_settings.c
@@ -712,6 +712,8 @@ __kmp_stg_print_inherit_fp_control( kmp_str_buf_t * buffer, char const * name, v
 // KMP_LIBRARY, OMP_WAIT_POLICY
 // -------------------------------------------------------------------------------------------------
 
+static char const *blocktime_str = NULL;
+
 static void
 __kmp_stg_parse_wait_policy( char const * name, char const * value, void * data ) {
 
@@ -725,9 +727,17 @@ __kmp_stg_parse_wait_policy( char const * name, char const * value, void * data
 
     if ( wait->omp ) {
         if ( __kmp_str_match( "ACTIVE", 1, value ) ) {
-           __kmp_library = library_turnaround;
+            __kmp_library = library_turnaround;
+            if ( blocktime_str == NULL ) {
+                // KMP_BLOCKTIME not specified, so set default to "infinite".
+                __kmp_dflt_blocktime = KMP_MAX_BLOCKTIME;
+            }
         } else if ( __kmp_str_match( "PASSIVE", 1, value ) ) {
-           __kmp_library = library_throughput;
+            __kmp_library = library_throughput;
+            if ( blocktime_str == NULL ) {
+                // KMP_BLOCKTIME not specified, so set default to 0.
+                __kmp_dflt_blocktime = 0;
+            }
         } else {
             KMP_WARNING( StgInvalidValue, name, value );
         }; // if
@@ -5025,6 +5035,9 @@ __kmp_env_initialize( char const * string ) {
         }
     }; // for i
 
+    // We need to know if blocktime was set when processing OMP_WAIT_POLICY
+    blocktime_str = __kmp_env_blk_var( & block, "KMP_BLOCKTIME" );
+
     // Special case. If we parse environment, not a string, process KMP_WARNINGS first.
     if ( string == NULL ) {
         char const * name  = "KMP_WARNINGS";