callgrind/tests/threads.c

   1 /* A simple example with 4 threads */
   2
   3 #include <pthread.h>
   4 #include <unistd.h>
   5
   6 double a[1000];
   7
   8 static void init()
   9 {
  10         int i;
  11         for(i=0;i<1000;i++) a[i] = (double)i;
  12 }
  13
  14 static void *th(void *v)
  15 {
  16         double sum = 0.0;
  17         int i,j;
  18
  19         for(j=0;j<1000;j++)
  20                 for(i=0;i<1000;i++)
  21                         sum += a[i];
  22
  23         *( (double*)v ) = sum;
  24
  25         /* make sure that no threads is so fast that it finishes
  26          * before last thread is created, thus reusing the TID */
  27         sleep(1);
  28
  29         return 0;
  30 }
  31
  32 int main()
  33 {
  34         pthread_t t[4];
  35         double sum[4];
  36         int i;
  37
  38         init();
  39
  40         for(i=0;i<4;i++)
  41                 pthread_create(&t[i], NULL, th, &sum[i]);
  42
  43         for(i=0;i<4;i++)
  44                 pthread_join(t[i], NULL);
  45
  46         return 0;
  47 }