[Openmp-commits] [PATCH] D19980: Fix team reuse with foreign threads.

[Jonathan Peyton via Openmp-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL269363: Fix team reuse with foreign threads (authored by jlpeyton).

Changed prior to commit:
  http://reviews.llvm.org/D19980?vs=56297&id=57104#toc

Repository:
  rL LLVM

http://reviews.llvm.org/D19980

Files:
  openmp/trunk/runtime/src/kmp_runtime.c
  openmp/trunk/runtime/test/misc_bugs/omp_foreign_thread_team_reuse.c

Index: openmp/trunk/runtime/src/kmp_runtime.c
===================================================================
--- openmp/trunk/runtime/src/kmp_runtime.c
+++ openmp/trunk/runtime/src/kmp_runtime.c
@@ -5219,6 +5219,8 @@
 
         // Reset pointer to parent team only for non-hot teams.
         team->t.t_parent = NULL;
+        team->t.t_level = 0;
+        team->t.t_active_level = 0;
 
         /* free the worker threads */
         for ( f = 1; f < team->t.t_nproc; ++ f ) {
Index: openmp/trunk/runtime/test/misc_bugs/omp_foreign_thread_team_reuse.c
===================================================================
--- openmp/trunk/runtime/test/misc_bugs/omp_foreign_thread_team_reuse.c
+++ openmp/trunk/runtime/test/misc_bugs/omp_foreign_thread_team_reuse.c
@@ -0,0 +1,82 @@
+// RUN: %libomp-compile-and-run
+#include <stdio.h>
+#include <pthread.h>
+#include "omp_testsuite.h"
+
+#define NUM_THREADS 10
+
+/*
+ After hot teams were enabled by default, the library started using levels
+ kept in the team structure.  The levels are broken in case foreign thread
+ exits and puts its team into the pool which is then re-used by another foreign
+ thread. The broken behavior observed is when printing the levels for each
+ new team, one gets 1, 2, 1, 2, 1, 2, etc.  This makes the library believe that
+ every other team is nested which is incorrect.  What is wanted is for the
+ levels to be 1, 1, 1, etc.
+*/
+
+int a = 0;
+int level;
+
+typedef struct thread_arg_t {
+  int iterations;
+} thread_arg_t;
+
+void* thread_function(void* arg) {
+  int i;
+  thread_arg_t* targ = (thread_arg_t*)arg;
+  int iterations = targ->iterations;
+  #pragma omp parallel private(i)
+  {
+    // level should always be 1
+    #pragma omp single
+    level = omp_get_level();
+
+    #pragma omp for
+    for(i = 0; i < iterations; i++) {
+      #pragma omp atomic
+      a++;
+    }
+  }
+}
+
+int test_omp_team_reuse()
+{
+  int i;
+  int success = 1;
+  pthread_t thread[NUM_THREADS];
+  thread_arg_t thread_arg[NUM_THREADS];
+  // launch NUM_THREADS threads, one at a time to perform thread_function()
+  for(i = 0; i < NUM_THREADS; i++) {
+    thread_arg[i].iterations = i + 1;
+    pthread_create(thread+i, NULL, thread_function, thread_arg+i);
+    pthread_join(*(thread+i), NULL);
+    // level read in thread_function()'s parallel region should be 1
+    if(level != 1) {
+      fprintf(stderr, "error: for pthread %d level should be 1 but "
+                      "instead equals %d\n", i, level);
+      success = 0;
+    }
+  }
+  // make sure the for loop works
+  int known_sum = (NUM_THREADS * (NUM_THREADS+1)) / 2;
+  if(a != known_sum) {
+    fprintf(stderr, "a should be %d but instead equals %d\n", known_sum, a);
+    success = 0;
+  }
+  return success;
+}
+
+int main()
+{
+  int i;
+  int num_failed=0;
+
+  for(i = 0; i < REPETITIONS; i++) {
+    a = 0;
+    if(!test_omp_team_reuse()) {
+      num_failed++;
+    }
+  }
+  return num_failed;
+}


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