openmp/runtime/test/worksharing/for/omp_for_nowait.c

   1 // RUN: %libomp-compile-and-run
   2 #include <stdio.h>
   3 #include "omp_testsuite.h"
   4
   5 /*
   6  * This test will hang if the nowait is not working properly.
   7  *
   8  * It relies on a thread skipping to the second for construct to
   9  * release the threads in the first for construct.
  10  *
  11  * Also, we use static scheduling to guarantee that one
  12  * thread will make it to the second for construct.
  13  */
  14 volatile int release;
  15 volatile int count;
  16
  17 void wait_for_release_then_increment(int rank)
  18 {
  19   fprintf(stderr, "Thread nr %d enters first for construct"
  20     " and waits.\n", rank);
  21   while (release == 0);
  22   #pragma omp atomic
  23   count++;
  24 }
  25
  26 void release_and_increment(int rank)
  27 {
  28   fprintf(stderr, "Thread nr %d sets release to 1\n", rank);
  29   release = 1;
  30   #pragma omp atomic
  31   count++;
  32 }
  33
  34 int test_omp_for_nowait()
  35 {
  36   release = 0;
  37   count = 0;
  38
  39   #pragma omp parallel num_threads(4)
  40   {
  41     int rank;
  42     int i;
  43
  44     rank = omp_get_thread_num();
  45
  46     #pragma omp for schedule(static) nowait
  47     for (i = 0; i < 4; i++) {
  48       if (i < 3)
  49         wait_for_release_then_increment(rank);
  50       else {
  51         fprintf(stderr, "Thread nr %d enters first for and goes "
  52           "immediately to the next for construct to release.\n", rank);
  53         #pragma omp atomic
  54         count++;
  55       }
  56     }
  57
  58     #pragma omp for schedule(static)
  59     for (i = 0; i < 4; i++) {
  60         release_and_increment(rank);
  61     }
  62   }
  63   return (count==8);
  64 }
  65
  66 int main()
  67 {
  68   int i;
  69   int num_failed=0;
  70
  71   for(i = 0; i < REPETITIONS; i++) {
  72     if(!test_omp_for_nowait()) {
  73       num_failed++;
  74     }
  75   }
  76   return num_failed;
  77 }