bat-lock.c

// Compiled with gcc -O

/*** Not locking ***/

#include <pthread.h>
#include <malloc.h>

int main() {
  int i;
  char *ba = malloc(100000000);
  for (i = 0; i < 80000000; i++) {
    ba[i] = 0;
  }

  // this is to stop the sneaky compiler from optimizing the whole lot away ;-)
  printf("%d\n", ba[70000000]);
}

// ./bat  0.05s user 0.03s system 97% cpu 0.082 total


/*** Locking ***/

#include <pthread.h>
#include <malloc.h>

int main() {
  pthread_mutex_t mutex;
  int i;
  char *ba = malloc(100000000);
  for (i = 0; i < 80000000; i++) {
    pthread_mutex_lock(&mutex);
    ba[i] = 0;
    pthread_mutex_unlock(&mutex);
  }

  // this is to stop the sneaky compiler from optimizing the whole lot away ;-)
  printf("%d\n", ba[70000000]);
}


// ./bat-lock  0.33s user 0.02s system 99% cpu 0.356 total