Testing Optimistic Locking

oplo.c

#include <pthread.h>
#include <stdatomic.h>
#include <stdbool.h>
#include <stdio.h>

#define MAX 90000

atomic_int count = ATOMIC_VAR_INIT(0);

int faltu = 0;

void *incrementCount(void *arg) {
  int oldValue = atomic_load(&count);
  int newValue = oldValue + 1;

  if (!atomic_compare_exchange_strong(&count, &oldValue, newValue)) {
    printf("Increment failed\n");
  }

  pthread_exit(NULL);
}

void *faltuKaj(void *arg) {
  faltu++;
  pthread_exit(NULL);
}

int main(void) {
  pthread_t threads[MAX];
  int i;
  for (i = 0; i < MAX; i++) {

    pthread_create(&threads[i], NULL, incrementCount, NULL);
  }

  for (int i = 0; i < MAX; i++) {

    pthread_join(threads[i], NULL);
  }

  pthread_t newThreads[MAX];

  for (i = 0; i < MAX; i++) {

    pthread_create(&newThreads[i], NULL, faltuKaj, NULL);
  }

  for (int i = 0; i < MAX; i++) {

    pthread_join(newThreads[i], NULL);
  }

  printf("Count = %d\n", count);
  printf("Faltu = %d\n", faltu);

  return 0;
}