helgrind/tests/tc14_laog_dinphils.c

   1
   2 #include <pthread.h>
   3 #include <stdlib.h>
   4 #include <unistd.h>
   5 #include <assert.h>
   6 /* Naive dining philosophers with inconsistent lock acquisition
   7    ordering. */
   8
   9 static pthread_t phil[5];
  10 static struct {
  11    pthread_mutex_t m;
  12    char pad[120 - sizeof(pthread_mutex_t)];
  13 } chop[5];
  14
  15 void* dine ( void* arg )
  16 {
  17    int i;
  18    long left = (long)arg;
  19    long right = (left + 1) % 5;
  20    for (i = 0; i < 1000/*arbitrary*/; i++) {
  21       pthread_mutex_lock(&chop[left].m);
  22       pthread_mutex_lock(&chop[right].m);
  23       /* eating */
  24       pthread_mutex_unlock(&chop[left].m);
  25       pthread_mutex_unlock(&chop[right].m);
  26    }
  27    return NULL;
  28 }
  29
  30 int main ( void )
  31 {
  32    long i;
  33    assert(sizeof(pthread_mutex_t) <= 120);
  34
  35    for (i = 0; i < 5; i++)
  36       pthread_mutex_init( &chop[i].m, NULL);
  37
  38    for (i = 0; i < 5; i++)
  39       pthread_create(&phil[i], NULL, dine, (void*)i );
  40
  41    sleep(1);
  42
  43    for (i = 0; i < 5; i++)
  44       pthread_join(phil[i], NULL);
  45
  46    return 0;
  47 }