멀티프로세스와 멀티쓰래드에서 CPU 배분 관련 내용입니다.

$ ls /sys/devices/virtual/cpuid/
cpu0  cpu1  cpu2  cpu3
$
$ cat thread-cpu.c
#define _GNU_SOURCE
#include <stdio.h>
#include <pthread.h>
#include <utmpx.h>
 
void *thread_fn(void *unused)
{
	printf("cpu: %d\n", sched_getcpu());
	return NULL;
}
 
#define NR_THREADS 4
int main(void)
{
	int i;
	void *ret;
	pthread_t thid[NR_THREADS];
 
	for (i = 0; i < NR_THREADS; i++)
		pthread_create(&thid[i], NULL, thread_fn, NULL);
 
	for (i = 0; i < NR_THREADS; i++)
		pthread_join(thid[i], &ret);
 
	return 0;
}
$
$ gcc thread-cpu.c -pthread
$ ./a.out
cpu: 3
cpu: 0
cpu: 1
cpu: 2