qemu_mutex_text

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

#if defined(SPIN)
pthread_spinlock_t m;
#else
pthread_mutex_t m = PTHREAD_MUTEX_INITIALIZER;
#endif

volatile unsigned long shared_val = 0;
int loop;

void* func(void* arg){
  int i;

  for(i=0; i<loop; i++){
#if defined(SPIN)
    pthread_spin_lock(&m);
#else
    pthread_mutex_lock(&m);
#endif

    shared_val++;

#if defined(SPIN)
    pthread_spin_unlock(&m);
#else
    pthread_mutex_unlock(&m);
#endif
  }
}

int main(int argc, char* argv[]){
  if(argc >= 2){
    loop = atoi(argv[1]);
  }
  else{
    loop = 1000;
  }

#if defined(SPIN)
  pthread_spin_init(&m, PTHREAD_PROCESS_SHARED);
#endif

  printf("thread acquire and release a lock %d times\n", loop);

  pthread_t pid1, pid2;

  pthread_create(&pid1, NULL, func, NULL);
  pthread_create(&pid2, NULL, func, NULL);

  pthread_join(pid1, NULL);
  pthread_join(pid2, NULL);
}