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@greensea
Created September 22, 2015 07:40
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比较 pthread_cond_wait 和 eventfd 的性能
#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>
#include <unistd.h>
#include <sys/eventfd.h>
#include <sys/time.h>
int g_loops = 0;
int g_efd = 0;
int g_stop = 0;
pthread_mutex_t cond_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
void* consumer_cond(void* ptr) {
pthread_mutex_lock(&cond_mutex);
while (g_loops > 0) {
g_loops--;
pthread_cond_wait(&cond, &cond_mutex);
}
pthread_mutex_unlock(&cond_mutex);
return NULL;
}
void* producer_cond(void* ptr) {
while (1 && !g_stop) {
pthread_mutex_lock(&cond_mutex);
pthread_cond_signal(&cond);
pthread_mutex_unlock(&cond_mutex);
}
return NULL;
}
void* consumer_eventfd(void* ptr) {
uint64_t buf;
while (g_loops > 0) {
g_loops--;
read(g_efd, &buf, 8);
}
return NULL;
}
void* producer_eventfd(void* ptr) {
uint64_t buf = 1;
while (1 && !g_stop) {
write(g_efd, &buf, 8);
}
return NULL;
}
void bench(int loops, int pcnt, int ccnt) {
void* ret;
int i;
pthread_t tidc[ccnt], tidp[pcnt];
struct timeval tv1, tv2;
float elapse;
g_efd = eventfd(0, EFD_SEMAPHORE);
g_loops = loops;
g_stop = 0;
gettimeofday(&tv1, NULL);
for (i = 0; i < ccnt; i++) {
pthread_create(&tidc[i], NULL, consumer_cond, NULL);
}
for (i = 0; i < pcnt; i++) {
pthread_create(&tidp[i], NULL, producer_cond, NULL);
}
for (i = 0; i < ccnt; i++) {
pthread_join(tidc[i], &ret);
}
for (i = 0; i < pcnt; i++) {
g_stop = 1;
pthread_join(tidp[i], &ret);
}
gettimeofday(&tv2, NULL);
elapse = (tv2.tv_sec - tv1.tv_sec) * 1000 * 1000 + (tv2.tv_usec - tv1.tv_usec);
elapse /= 1000 * 1000;
printf("pthread_cond 耗时 %f 秒\n", elapse);
g_loops = loops;
g_stop = 0;
gettimeofday(&tv1, NULL);
for (i = 0; i < ccnt; i++) {
pthread_create(&tidc[i], NULL, consumer_eventfd, NULL);
}
for (i = 0; i < pcnt; i++) {
pthread_create(&tidp[i], NULL, producer_eventfd, NULL);
}
for (i = 0; i < ccnt; i++) {
pthread_join(tidc[i], &ret);
}
for (i = 0; i < pcnt; i++) {
g_stop = 1;
pthread_join(tidp[i], &ret);
}
gettimeofday(&tv2, NULL);
elapse = (tv2.tv_sec - tv1.tv_sec) * 1000 * 1000 + (tv2.tv_usec - tv1.tv_usec);
elapse /= 1000 * 1000;
printf("pthread_eventfd 耗时 %f 秒\n", elapse);
}
int main() {
int i;
for (i = 1; i <= 100000; i *= 10) {
printf("进行 %d 次循环测试\n", i);
bench(i, 1, 1);
printf("=============\n");
}
return 0;
}
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