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/*
* barrier5.c
*
* Declare a single barrier object, set up a sequence of
* barrier points to prove lockstepness, and then destroy it.
*
*/
#include "test.h"
enum {
NUMTHREADS = 16,
BARRIERS = 10000
};
pthread_barrier_t barrier = NULL;
pthread_mutex_t mx = PTHREAD_MUTEX_INITIALIZER;
int barrierReleases[BARRIERS + 1];
void *
func(void * barrierHeight)
{
int i;
int result;
int serialThreads = 0;
for (i = 1; i < BARRIERS; i++)
{
result = pthread_barrier_wait(&barrier);
assert(pthread_mutex_lock(&mx) == 0);
barrierReleases[i]++;
assert(pthread_mutex_unlock(&mx) == 0);
/*
* Confirm the correct number of releases from the previous
* barrier. We can't do the current barrier yet because there may
* still be threads waking up.
*/
if (result == PTHREAD_BARRIER_SERIAL_THREAD)
{
serialThreads++;
assert(barrierReleases[i - 1] == (int) barrierHeight);
barrierReleases[i + 1] = 0;
}
else if (result != 0)
{
printf("Barrier failed: result = %s\n", error_string[result]);
fflush(stdout);
return NULL;
}
}
return (void *) serialThreads;
}
int
main()
{
int i, j;
int result;
int serialThreadsTotal;
pthread_t t[NUMTHREADS + 1];
for (j = 1; j <= NUMTHREADS; j++)
{
printf("Barrier height = %d\n", j);
barrierReleases[0] = j;
barrierReleases[1] = 0;
assert(pthread_barrier_init(&barrier, NULL, j) == 0);
for (i = 1; i <= j; i++)
{
assert(pthread_create(&t[i], NULL, func, (void *) j) == 0);
}
serialThreadsTotal = 0;
for (i = 1; i <= j; i++)
{
assert(pthread_join(t[i], (void **) &result) == 0);
serialThreadsTotal += result;
}
assert(serialThreadsTotal == BARRIERS - 1);
assert(barrierReleases[BARRIERS - 1] == j);
assert(barrierReleases[BARRIERS] == 0);
assert(pthread_barrier_destroy(&barrier) == 0);
}
assert(pthread_mutex_destroy(&mx) == 0);
return 0;
}
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