openmp/runtime/test/env/omp_thread_limit.c

   1 // RUN: %libomp-compile && env OMP_THREAD_LIMIT=4 %libomp-run 4
   2 // RUN: %libomp-compile && env OMP_THREAD_LIMIT=7 %libomp-run 7
   3 //
   4 // OMP_THREAD_LIMIT=N should imply that no more than N threads are active in
   5 // a contention group
   6 #include <stdio.h>
   7 #include <string.h>
   8 #include <limits.h>
   9 #include "omp_testsuite.h"
  10
  11 int failed = 0;
  12
  13 void usage() {
  14     fprintf(stderr, "usage: omp_thread_limit <n>\n");
  15 }
  16
  17 void verify(const char* file_name, int line_number, int team_size) {
  18   int num_threads = omp_get_num_threads();
  19   if (team_size != num_threads) {
  20 #pragma omp critical(A)
  21     {
  22       char label[256];
  23       snprintf(label, sizeof(label), "%s:%d", file_name, line_number);
  24       failed = 1;
  25       printf("failed: %s: team_size(%d) != omp_get_num_threads(%d)\n",
  26              label, team_size, num_threads);
  27     }
  28   }
  29 }
  30
  31 int main(int argc, char** argv)
  32 {
  33   int cl_thread_limit;
  34
  35   if (argc != 2) {
  36     usage();
  37     return 1;
  38   }
  39   cl_thread_limit = atoi(argv[1]);
  40
  41   omp_set_dynamic(0);
  42   if (omp_get_thread_limit() != cl_thread_limit) {
  43     fprintf(stderr, "omp_get_thread_limit failed with %d, should be%d\n",
  44             omp_get_thread_limit(), cl_thread_limit);
  45     return 1;
  46   }
  47   else if (omp_get_max_threads() > cl_thread_limit) {
  48 #if _OPENMP
  49     int team_size = cl_thread_limit;
  50 #else
  51     int team_size = 1;
  52 #endif
  53     omp_set_num_threads(19);
  54     verify(__FILE__, __LINE__, 1);
  55 #pragma omp parallel
  56     {
  57       verify(__FILE__, __LINE__, team_size);
  58       verify(__FILE__, __LINE__, team_size);
  59     }
  60     verify(__FILE__, __LINE__, 1);
  61
  62     omp_set_nested(1);
  63 #pragma omp parallel num_threads(3)
  64     {
  65       verify(__FILE__, __LINE__, 3);
  66 #pragma omp master
  67 #pragma omp parallel num_threads(21)
  68       {
  69         verify(__FILE__, __LINE__, team_size-2);
  70         verify(__FILE__, __LINE__, team_size-2);
  71       }
  72     }
  73     verify(__FILE__, __LINE__, 1);
  74
  75     return failed;
  76   } else {
  77     fprintf(stderr, "This test is not applicable for max num_threads='%d'\n",
  78             omp_get_max_threads());
  79     return 0;
  80   }
  81
  82 }