#define _GNU_SOURCE

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/sysinfo.h>
#include <unistd.h>
#include <sched.h>
#include <ctype.h>
#include <string.h>
#include <pthread.h>

int num = 0;
int test[65535];

int mess_rw(int data)
{
    int i;

    while (1) {
        for (i = 0; i < (sizeof(test) / sizeof(test[0])); i++) {
            if (test[i] != data)
                test[i] = data;
        }
    }
}

void *test_thread(void *arg)
{
    int cpu = *(int *)arg;
    cpu_set_t mask;

    CPU_ZERO(&mask);
    CPU_SET(cpu, &mask);
    if (!sched_setaffinity(0, sizeof(mask), &mask))
        printf("thread %d: running on cpu %d\n", cpu, cpu);
    else
        printf("thread %d: fail to set CPU affinity\n", cpu);

    mess_rw(cpu);

    return NULL;
}

int main(int argc, char *argv[])
{
    num = sysconf(_SC_NPROCESSORS_CONF);
    pthread_t thread[num];
    int id[num];
    int i;

    printf("PID %d on system with %d processor(s)\n", getpid(), num);

    for (i = 0; i < num; i++) {
        id[i] = i;
        pthread_create(&thread[i], NULL, test_thread, (void *)&id[i]);
    }

    for (i = 0; i < num; i++) {
        pthread_join(thread[i], NULL);
    }

    return 0;
}