pthread_cond_signal benchmark

cond_signal_benchmark.c

#include <pthread.h>
#include <sys/time.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

long long TEST_NUMBER ;

typedef struct {
	pthread_mutex_t mutex;
	pthread_cond_t cond;
	long long queue_count;
	long long recv_count;	
	long long cond_wait;
	long long cond_pass;
} bridge_t ;

void * sender (void * obj) {
	long long i;
	bridge_t * b = (bridge_t *)obj;
	for (i = 0; i < TEST_NUMBER; i++) {
		pthread_mutex_lock (&b->mutex);
		b->queue_count++;
		pthread_cond_signal (&b->cond);
		pthread_mutex_unlock (&b->mutex);		
	}
	return NULL;
}

void * recver (void * obj) {
	bridge_t * b = (bridge_t *)obj;
	int q = 0;
	while (1) {
		pthread_mutex_lock (&b->mutex);
		if (b->queue_count == 0) {
			pthread_cond_wait (&b->cond, &b->mutex);			
			b->cond_wait++;			
		}
		else {
			b->cond_pass++;
		}
		q = b->queue_count;
		b->queue_count = 0;
		pthread_mutex_unlock (&b->mutex);

		b->recv_count += q;
		if (b->recv_count >= TEST_NUMBER)
			break;
	}

	return NULL;	
}

int main (int argc, char *argv[]) {
	bridge_t b;
	pthread_t th_s, th_r;
	struct timeval ts_start, ts_end, ts;
	char *e;

	if (argc != 2) {
		printf ("give me test loop number!\n");
		exit (EXIT_FAILURE);
	}
	TEST_NUMBER = strtoll (argv[1], &e, 0);
	if (*e != '\0') {
		printf ("invalid number!\n");
		exit (EXIT_FAILURE);		
	}
	pthread_mutex_init (&(b.mutex), NULL);
	pthread_cond_init (&(b.cond), NULL);
	b.queue_count = 0;
	b.recv_count  = 0;
	b.cond_wait = 0;
	b.cond_pass = 0;
	gettimeofday (&ts_start, NULL);
	pthread_create (&th_s, NULL, sender, &b);
	pthread_create (&th_r, NULL, recver, &b);

	pthread_join (th_s, NULL);
	pthread_join (th_r, NULL);

	gettimeofday (&ts_end, NULL);
	timersub (&ts_end, &ts_start, &ts);
	
	double duration = (double)ts.tv_sec + ((double)ts.tv_usec) / 1000000;
	double mps = (double)TEST_NUMBER / duration;
	printf ("%lld, %10.6f, %lld, %lld\n", TEST_NUMBER, mps, b.cond_wait, b.cond_pass);
	return 0;
}