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Prevent monitor thread creation when KMP_BLOCKTIME="infinite" 

When users sets envirable KMP_BLOCKTIME to "infinite" (the time one busy-waits
at barrieres, etc.), the monitor thread is not useful and can be ignored. This
change prevents the creation of the monitor thread when the users sets
KMP_BLOCKTIME to "infinite".

Differential Revision: http://reviews.llvm.org/D15628

llvm-svn: 256061
This commit is contained in:
Jonathan Peyton 2015-12-18 23:20:36 +00:00
parent 6cb33c60bd
commit 4fee5f6416
2 changed files with 17 additions and 0 deletions
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8
openmp/runtime/src/z_Linux_util.c
View File

@ -1123,6 +1123,13 @@ __kmp_create_monitor( kmp_info_t *th )
int status;
int auto_adj_size = FALSE;
if( __kmp_dflt_blocktime == KMP_MAX_BLOCKTIME ) {
// We don't need monitor thread in case of MAX_BLOCKTIME
KA_TRACE( 10, ("__kmp_create_monitor: skipping monitor thread because of MAX blocktime\n" ) );
th->th.th_info.ds.ds_tid = 0; // this makes reap_monitor no-op
th->th.th_info.ds.ds_gtid = 0;
return;
}
KA_TRACE( 10, ("__kmp_create_monitor: try to create monitor\n" ) );
KMP_MB(); /* Flush all pending memory write invalidates. */
@ -1291,6 +1298,7 @@ __kmp_reap_monitor( kmp_info_t *th )
// If both tid and gtid are KMP_GTID_DNE, the monitor has been shut down.
KMP_DEBUG_ASSERT( th->th.th_info.ds.ds_tid == th->th.th_info.ds.ds_gtid );
if ( th->th.th_info.ds.ds_gtid != KMP_GTID_MONITOR ) {
KA_TRACE( 10, ("__kmp_reap_monitor: monitor did not start, returning\n") );
return;
}; // if

9
openmp/runtime/src/z_Windows_NT_util.c
View File

@ -1429,6 +1429,14 @@ __kmp_create_monitor( kmp_info_t *th )
DWORD idThread;
int ideal, new_ideal;
if( __kmp_dflt_blocktime == KMP_MAX_BLOCKTIME ) {
// We don't need monitor thread in case of MAX_BLOCKTIME
KA_TRACE( 10, ("__kmp_create_monitor: skipping monitor thread because of MAX blocktime\n" ) );
th->th.th_info.ds.ds_tid = 0; // this makes reap_monitor no-op
th->th.th_info.ds.ds_gtid = 0;
TCW_4( __kmp_init_monitor, 2 ); // Signal to stop waiting for monitor creation
return;
}
KA_TRACE( 10, ("__kmp_create_monitor: try to create monitor\n" ) );
KMP_MB(); /* Flush all pending memory write invalidates. */
@ -1613,6 +1621,7 @@ __kmp_reap_monitor( kmp_info_t *th )
// If both tid and gtid are KMP_GTID_DNE, the monitor has been shut down.
KMP_DEBUG_ASSERT( th->th.th_info.ds.ds_tid == th->th.th_info.ds.ds_gtid );
if ( th->th.th_info.ds.ds_gtid != KMP_GTID_MONITOR ) {
KA_TRACE( 10, ("__kmp_reap_monitor: monitor did not start, returning\n") );
return;
}; // if