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glibc/linuxthreads/Examples/ex14.c
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/* Test of POSIX barriers. */ | |
#include <pthread.h> | |
#include <stdio.h> | |
#include <stdlib.h> | |
#include <string.h> | |
#define NTHREADS 20 | |
#define ROUNDS 20 | |
static pthread_barrier_t barriers[NTHREADS]; | |
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER; | |
static int counters[NTHREADS]; | |
static int serial[NTHREADS]; | |
static void * | |
worker (void *arg) | |
{ | |
void *result = NULL; | |
int nr = (long int) arg; | |
int i; | |
for (i = 0; i < ROUNDS; ++i) | |
{ | |
int j; | |
int retval; | |
if (nr == 0) | |
{ | |
memset (counters, '\0', sizeof (counters)); | |
memset (serial, '\0', sizeof (serial)); | |
} | |
retval = pthread_barrier_wait (&barriers[NTHREADS - 1]); | |
if (retval != 0 && retval != PTHREAD_BARRIER_SERIAL_THREAD) | |
{ | |
printf ("thread %d failed to wait for all the others\n", nr); | |
result = (void *) 1; | |
} | |
for (j = nr; j < NTHREADS; ++j) | |
{ | |
/* Increment the counter for this round. */ | |
pthread_mutex_lock (&lock); | |
++counters[j]; | |
pthread_mutex_unlock (&lock); | |
/* Wait for the rest. */ | |
retval = pthread_barrier_wait (&barriers[j]); | |
/* Test the result. */ | |
if (nr == 0 && counters[j] != j + 1) | |
{ | |
printf ("barrier in round %d released but count is %d\n", | |
j, counters[j]); | |
result = (void *) 1; | |
} | |
if (retval != 0) | |
{ | |
if (retval != PTHREAD_BARRIER_SERIAL_THREAD) | |
{ | |
printf ("thread %d in round %d has nonzero return value != PTHREAD_BARRIER_SERIAL_THREAD\n", | |
nr, j); | |
result = (void *) 1; | |
} | |
else | |
{ | |
pthread_mutex_lock (&lock); | |
++serial[j]; | |
pthread_mutex_unlock (&lock); | |
} | |
} | |
/* Wait for the rest again. */ | |
retval = pthread_barrier_wait (&barriers[j]); | |
/* Now we can check whether exactly one thread was serializing. */ | |
if (nr == 0 && serial[j] != 1) | |
{ | |
printf ("not exactly one serial thread in round %d\n", j); | |
result = (void *) 1; | |
} | |
} | |
} | |
return result; | |
} | |
#define TEST_FUNCTION do_test () | |
#define TIMEOUT 60 | |
int | |
do_test (void) | |
{ | |
pthread_t threads[NTHREADS]; | |
int i; | |
void *res; | |
int result = 0; | |
/* Initialized the barrier variables. */ | |
for (i = 0; i < NTHREADS; ++i) | |
if (pthread_barrier_init (&barriers[i], NULL, i + 1) != 0) | |
{ | |
printf ("Failed to initialize barrier %d\n", i); | |
exit (1); | |
} | |
/* Start the threads. */ | |
for (i = 0; i < NTHREADS; ++i) | |
if (pthread_create (&threads[i], NULL, worker, (void *) (long int) i) != 0) | |
{ | |
printf ("Failed to start thread %d\n", i); | |
exit (1); | |
} | |
/* And wait for them. */ | |
for (i = 0; i < NTHREADS; ++i) | |
if (pthread_join (threads[i], &res) != 0 || res != NULL) | |
{ | |
printf ("thread %d returned a failure\n", i); | |
result = 1; | |
} | |
if (result == 0) | |
puts ("all OK"); | |
return result; | |
} | |
#include "../test-skeleton.c" |