drd/tests/pth_barrier.c

   1 /* Test whether all data races are detected in a multithreaded program with
   2  * barriers.
   3  */
   4
   5
   6 #define _GNU_SOURCE
   7
   8 /***********************/
   9 /* Include directives. */
  10 /***********************/
  11
  12 #include <assert.h>
  13 #include <limits.h>
  14 #include <pthread.h>
  15 #include <stdint.h>
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <string.h>
  19
  20
  21 /*********************/
  22 /* Type definitions. */
  23 /*********************/
  24
  25 struct threadinfo
  26 {
  27   pthread_barrier_t* b;
  28   pthread_t          tid;
  29   int8_t*            array;
  30   int                iterations;
  31 };
  32
  33
  34 /********************/
  35 /* Local variables. */
  36 /********************/
  37
  38 static int s_silent;
  39
  40
  41 /*************************/
  42 /* Function definitions. */
  43 /*************************/
  44
  45 /** Single thread, which touches p->iterations elements of array p->array.
  46  * Each modification of an element of p->array is a data race. */
  47 static void* threadfunc(struct threadinfo* p)
  48 {
  49   int i;
  50   int8_t* const array = p->array;
  51   pthread_barrier_t* const b = p->b;
  52   if (! s_silent)
  53     printf("thread %lx iteration 0\n", (long) pthread_self());
  54   pthread_barrier_wait(b);
  55   for (i = 0; i < p->iterations; i++)
  56   {
  57     if (! s_silent)
  58       printf("thread %lx iteration %d; writing to %p\n",
  59              (long) pthread_self(), i + 1, &array[i]);
  60     array[i] = i;
  61     pthread_barrier_wait(b);
  62   }
  63   return 0;
  64 }
  65
  66 /** Actual test, consisting of nthread threads. */
  67 static void barriers_and_races(const int nthread, const int iterations)
  68 {
  69   int i, res;
  70   pthread_attr_t attr;
  71   struct threadinfo* t;
  72   pthread_barrier_t b;
  73   int8_t* array;
  74
  75   t = malloc(nthread * sizeof(struct threadinfo));
  76   array = malloc(iterations * sizeof(array[0]));
  77
  78   if (! s_silent)
  79     printf("&array[0] = %p\n", array);
  80
  81   pthread_barrier_init(&b, 0, nthread);
  82
  83   pthread_attr_init(&attr);
  84   res = pthread_attr_setstacksize(&attr, PTHREAD_STACK_MIN + 4096);
  85   assert(res == 0);
  86
  87   for (i = 0; i < nthread; i++)
  88   {
  89     t[i].b = &b;
  90     t[i].array = array;
  91     t[i].iterations = iterations;
  92     res = pthread_create(&t[i].tid, &attr, (void*(*)(void*))threadfunc, &t[i]);
  93     if (res != 0) {
  94       fprintf(stderr, "Could not create thread #%d (of %d): %s\n",
  95               i, nthread, strerror(res));
  96       exit(1);
  97     }
  98   }
  99
 100   pthread_attr_destroy(&attr);
 101
 102   for (i = 0; i < nthread; i++)
 103   {
 104     pthread_join(t[i].tid, 0);
 105   }
 106
 107   pthread_barrier_destroy(&b);
 108
 109   free(array);
 110   free(t);
 111 }
 112
 113 int main(int argc, char** argv)
 114 {
 115   int nthread;
 116   int iterations;
 117
 118   nthread    = (argc > 1) ? atoi(argv[1]) : 2;
 119   iterations = (argc > 2) ? atoi(argv[2]) : 3;
 120   s_silent   = (argc > 3) ? atoi(argv[3]) : 0;
 121
 122   barriers_and_races(nthread, iterations);
 123
 124   return 0;
 125 }