CPU Affinity

用 pthread_setaffinity_np() 就可以指定 thread 用 CPU 的某幾個 core 去跑，直接看下面的 example，CPU core 編號從 0 開始。

#include <stdio.h>
#include <math.h>
#include <boost/bind.hpp>
#include <tbb/tbb_thread.h>

void func(int id, int cpu)
{
    cpu_set_t mask;
    CPU_ZERO(&mask);
    CPU_SET(cpu, &mask);
    if (pthread_setaffinity_np(pthread_self(), sizeof(mask), &mask) < 0)
    {
        perror("pthread_setaffinity_np failed");
    }

    long tmp = 0;
    long i = 0;
    while (i < (cpu+1) * 100000000)
    {
        i++;
        tmp += sqrt(i);
    }

    printf("thread %d: %ld\n", id, tmp);
}

int main ()
{
    tbb::tbb_thread thread0(boost::bind(&func, 0, 3));
    tbb::tbb_thread thread1(boost::bind(&func, 1, 2));
    tbb::tbb_thread thread2(boost::bind(&func, 2, 1));
    tbb::tbb_thread thread3(boost::bind(&func, 3, 0));

    thread0.join();
    thread1.join();
    thread2.join();
    thread3.join();

    return 0;
}