cpuset

cpuset.c

// This is a simple program to demonstrate the use of the cpuset

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sched.h>
#include <sys/types.h>
#include <sys/syscall.h>

#define NUM_THREADS 2

void *thread_func(void *arg)
{
    int i;
    int cpu;
    cpu_set_t cpuset;

    cpu = sched_getcpu();
    printf("Thread %d running on CPU %d\n", (int)arg, cpu);

    CPU_ZERO(&cpuset);
    CPU_SET(cpu, &cpuset);

    if (sched_setaffinity(0, sizeof(cpu_set_t), &cpuset) == -1) {
        perror("sched_setaffinity");
        exit(1);
    }

    for (i = 0; i < 100000000; i++)
        ;

    return NULL;
}

int main(int argc, char *argv[])
{
    int i;
    pthread_t tid[NUM_THREADS];

    for (i = 0; i < NUM_THREADS; i++) {
        if (pthread_create(&tid[i], NULL, thread_func, (void *)i) != 0) {
            perror("pthread_create");
            exit(1);
        }
    }

    for (i = 0; i < NUM_THREADS; i++) {
        if (pthread_join(tid[i], NULL) != 0) {
            perror("pthread_join");
            exit(1);
        }
    }

    return 0;
}

cpuset.md

#!/bin/bash

# Set CPU affinity for process
taskset -c 0,1,2,3 ./my_program

// Set CPU affinity for thread
pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpuset);

// Set CPU affinity for process using percpu variable
cpumask_t mask;
cpumask_clear(&mask);
cpumask_set_cpu(0, &mask);
cpumask_set_cpu(1, &mask);
cpumask_set_cpu(2, &mask);
cpumask_set_cpu(3, &mask);
set_cpus_allowed_ptr(current, &mask);