我正在开发x86架构的4核服务器. uname如下.

Linux 2.6.9-22.ELsmp#1 SMP Mon Sep 19 18:00:54 EDT 2005 x86_64 x86_64 x86_64 GNU / Linux

#include <stdio.h>
#include <pthread.h>
#include <asm-x86_64/atomic.h>

int n = 0;
atomic_t v;
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

#define LOOP 10000

void* foo(void *p)
{
    int i = 0;
    for(i = 0; i < LOOP; i++) {
//        pthread_mutex_lock(&mutex);
        ++n;
        --n;
        atomic_inc(&v);
        atomic_dec(&v);
//        pthread_mutex_unlock(&mutex);
    }

    return NULL;
}

#define COUNT 50

int main(int argc,char **argv)
{
    int i;
    pthread_t pids[COUNT];
    pthread_attr_t attr;
    pthread_attr_init(&attr);
    atomic_set(&v,0);

    for(i = 0; i < COUNT; i++) {
        pthread_create(&pids[i],&attr,foo,NULL);
    }

    for(i = 0; i < COUNT; i++) {
        pthread_join(pids[i],NULL);
    }

    printf("%d\n",n);
    printf("%d\n",v);
    return 0;
}