transactonal memory dining philosopers

trans.c

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

typedef struct { int food; } philosoper_type;

static inline int eat(philosoper_type *philo, int *lfork, int *rfork) {
  int r = 0;
  while (!r) {
    __transaction_atomic {
      if (!(*lfork) && !(*rfork)) {
        *lfork = *rfork = 1;
        philo->food++;
        r = 1;
        *lfork = *rfork = 0;
      }
    }
  }
  return r;
}

typedef struct {
  int *lfork;
  int *rfork;
  philosoper_type philo;
  int food_to_eat;
} thread_msg_type;

void *eat_philo_eat(void *msg) {
  thread_msg_type *m = (thread_msg_type *)msg;
  for (int i=0;i < m->food_to_eat;++i) {
    eat( &m->philo, m->lfork, m->rfork);
  }
  return NULL;
}

int main() {
  const int N = 5;
  const int food = 1000000;

  pthread_t threads[N];
  int forks[N];
  thread_msg_type msg[N];

  for (int i = 0; i < N; ++i) {
    forks[i] = 0;
    msg[i].lfork = &forks[i];
    msg[i].rfork = &forks[(i+1)%N];
    msg[i].food_to_eat = food;
    int r = pthread_create(&threads[i], NULL, eat_philo_eat, &msg[i]);
    assert(r == 0);
  }

  for (int i = 0; i < N; ++i) {
    int r = pthread_join(threads[i], NULL);
    assert(r == 0);
  }
  printf("done\n");
}