[Openmp-commits] [PATCH] D20539: Fix for OMP_PROC_BIND=spread strategy

[Terry Wilmarth via Openmp-commits]

tlwilmar created this revision.
tlwilmar added reviewers: AndreyChurbanov, jlpeyton, hbae.
tlwilmar added a subscriber: openmp-commits.
tlwilmar set the repository for this revision to rL LLVM.

The OMP_PROC_BIND=spread strategy fails to assign the master thread the correct place partition after the first parallel region.  Other threads in the hot team will remember their place_partition, but the master's place partition is restored to what it was before entering the parallel region.  So when the hot team is used for subsequent parallel regions, the master has lost this info. This fix calls __kmp_place_partitions to update only the master thread's place partition in the spread case when there are no other changes to the hot team.


Repository:
  rL LLVM

http://reviews.llvm.org/D20539

Files:
  runtime/src/kmp_runtime.c

Index: runtime/src/kmp_runtime.c
===================================================================
--- runtime/src/kmp_runtime.c
+++ runtime/src/kmp_runtime.c
@@ -70,7 +70,7 @@
 static void __kmp_initialize_info( kmp_info_t *, kmp_team_t *, int tid, int gtid );
 static void __kmp_initialize_team( kmp_team_t * team, int new_nproc, kmp_internal_control_t * new_icvs, ident_t * loc );
 #if OMP_40_ENABLED && KMP_AFFINITY_SUPPORTED
-static void __kmp_partition_places( kmp_team_t *team );
+static void __kmp_partition_places( kmp_team_t *team, int update_master_only=0 );
 #endif
 static void __kmp_do_serial_initialize( void );
 void __kmp_fork_barrier( int gtid, int tid );
@@ -4436,7 +4436,7 @@
 // The master thread's partition should already include its current binding.
 //
 static void
-__kmp_partition_places( kmp_team_t *team )
+__kmp_partition_places( kmp_team_t *team, int update_master_only )
 {
     //
     // Copy the master thread's place partion to the team struct
@@ -4582,6 +4582,7 @@
             int f;
             int n_th = team->t.t_nproc;
             int n_places;
+            int thidx;
             if ( first_place <= last_place ) {
                 n_places = last_place - first_place + 1;
             }
@@ -4595,7 +4596,10 @@
                 rem = n_places - n_th*S;
                 gap = rem ? n_th/rem : 1;
                 gap_ct = gap;
-                for ( f = 0; f < n_th; f++ ) {
+                thidx = n_th;
+                if (update_master_only == 1)
+                    thidx = 1;
+                for ( f = 0; f < thidx; f++ ) {
                     kmp_info_t *th = team->t.t_threads[f];
                     KMP_DEBUG_ASSERT( th != NULL );
 
@@ -4655,7 +4659,10 @@
                 gap = rem > 0 ? n_places/rem : n_places;
                 int place = masters_place;
                 int gap_ct = gap;
-                for ( f = 0; f < n_th; f++ ) {
+                thidx = n_th;
+                if (update_master_only == 1)
+                    thidx = 1;
+                for ( f = 0; f < thidx; f++ ) {
                     kmp_info_t *th = team->t.t_threads[f];
                     KMP_DEBUG_ASSERT( th != NULL );
 
@@ -4802,6 +4809,9 @@
 # if KMP_AFFINITY_SUPPORTED
             if ( ( team->t.t_size_changed == 0 )
               && ( team->t.t_proc_bind == new_proc_bind ) ) {
+                if (new_proc_bind == proc_bind_spread) {
+                    __kmp_partition_places(team, 1); // add flag to update only master for spread
+                }
                 KA_TRACE( 200, ("__kmp_allocate_team: reusing hot team #%d bindings: proc_bind = %d, partition = [%d,%d]\n",
                   team->t.t_id, new_proc_bind, team->t.t_first_place,
                   team->t.t_last_place ) );


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D20539.58143.patch
Type: text/x-patch
Size: 2760 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/openmp-commits/attachments/20160523/0b0bcc8c/attachment.bin>