[Openmp-commits] [PATCH] D142247: Fix initialization of th_task_state on each thread on expanding hot teams.

[Terry Wilmarth via Phabricator via Openmp-commits]

tlwilmar created this revision.
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The th_task_state was initialized from the master thread's value, or from its memo stack, but this causes problems because neither of those may have the right value at the right time. However, other threads in the team are guaranteed to have the right values, so we change the initialize the new threads' th_task_state from the th_task_state of the last of the older threads in the hot team.

Fix #56307.


Repository:
  rOMP OpenMP

https://reviews.llvm.org/D142247

Files:
  openmp/runtime/src/kmp_runtime.cpp


Index: openmp/runtime/src/kmp_runtime.cpp
===================================================================
--- openmp/runtime/src/kmp_runtime.cpp
+++ openmp/runtime/src/kmp_runtime.cpp
@@ -5444,21 +5444,10 @@
         __kmp_initialize_info(team->t.t_threads[f], team, f,
                               __kmp_gtid_from_tid(f, team));
 
-      if (level) { // set th_task_state for new threads in nested hot team
-        // __kmp_initialize_info() no longer zeroes th_task_state, so we should
-        // only need to set the th_task_state for the new threads. th_task_state
-        // for primary thread will not be accurate until after this in
-        // __kmp_fork_call(), so we look to the primary thread's memo_stack to
-        // get the correct value.
-        for (f = old_nproc; f < team->t.t_nproc; ++f)
-          team->t.t_threads[f]->th.th_task_state =
-              team->t.t_threads[0]->th.th_task_state_memo_stack[level];
-      } else { // set th_task_state for new threads in non-nested hot team
-        // copy primary thread's state
-        kmp_uint8 old_state = team->t.t_threads[0]->th.th_task_state;
-        for (f = old_nproc; f < team->t.t_nproc; ++f)
-          team->t.t_threads[f]->th.th_task_state = old_state;
-      }
+      // set th_task_state for new threads in hot team with older thread's state
+      kmp_uint8 old_state = team->t.t_threads[old_nproc - 1]->th.th_task_state;
+      for (f = old_nproc; f < team->t.t_nproc; ++f)
+        team->t.t_threads[f]->th.th_task_state = old_state;
 
 #ifdef KMP_DEBUG
       for (f = 0; f < team->t.t_nproc; ++f) {


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