linux affinity

现在的CPU几乎都是多核，所以，分配给予进程相同数量的线程是合理的需求

但是，这些线程不一定就均匀跑在这些内核上

所以，我们要指派，“一个线程就运行在一个固定的CPU内核上”

//test.c

#define _GNU_SOURCE

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <pthread.h>

#include <sched.h>

void *myfun(void *arg)

{

cpu_set_t mask;

cpu_set_t get;

char buf[256];

int i;

int j;

int num = sysconf(_SC_NPROCESSORS_CONF);

printf("system has %d processor(s)\n", num);

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

CPU_ZERO(&mask);

CPU_SET(i, &mask);

if (pthread_setaffinity_np(pthread_self(), sizeof(mask), &mask) < 0) {

fprintf(stderr, "set thread affinity failed\n");

}

CPU_ZERO(&get);

if (pthread_getaffinity_np(pthread_self(), sizeof(get), &get) < 0) {

fprintf(stderr, "get thread affinity failed\n");

}

for (j = 0; j < num; j++) {

if (CPU_ISSET(j, &get)) {

printf("thread %d is running in processor %d\n", (int)pthread_self(), j);

}

}

j = 0;

while (j++ < 100000000) {

memset(buf, 0, sizeof(buf));

}

}

pthread_exit(NULL);

}

int main(int argc, char *argv[])

{

pthread_t tid;

if (pthread_create(&tid, NULL, (void *)myfun, NULL) != 0) {

fprintf(stderr, "thread create failed\n");

return -1;

}

pthread_join(tid, NULL);

return 0;

}

//result

#gcc -o test.o -c test.c

#gcc -o test test.o -lpthread

#./test

Finally:

这项技术特别有用，不多说了