多线程并发锁方案—自旋锁

#include <stdio.h>
#include <pthread.h>
#define THREAD_COUNT  10
pthread_mutex_t mutex;
pthread_spinlock_t spinlock;     //spinlock定义
void *thread_callback(void *arg) {
  int *pcount = (int *)arg;
  int i = 0;
  while (i ++ < 100000) {
#if 0
    (*pcount) ++; //
#elif 0
    pthread_mutex_lock(&mutex);
    (*pcount) ++; //
    pthread_mutex_unlock(&mutex);
#else
    pthread_spin_lock(&spinlock);
    (*pcount) ++; //
    pthread_spin_unlock(&spinlock);
#endif
    usleep(1);
  }
}
int main () {
  pthread_t threadid[THREAD_COUNT] = {0};
  pthread_mutex_init(&mutex, NULL);
  pthread_spin_init(&spinlock, PTHREAD_PROCESS_SHARED);  //初始化，第二个参数是否进程共享
  int i = 0;
  int count = 0;
  for (i = 0;i < THREAD_COUNT;i ++) {
    pthread_create(&threadid[i], NULL, thread_callback, &count);
  }
  for (i = 0;i < 100;i ++) {
    printf("count : %d\n", count);
    sleep(1);
  }
}