CPU Affinity

Question

Is there a progamatic method to set CPU affinity for a process in c/c++ for the linux operating system.

Answer 1

You need to use sched_setaffinity(2)

For example, to run on CPUs 0 and 2 only:

#include <sched.h>

cpu_set_t  mask;
CPU_ZERO(&mask);
CPU_SET(0, &mask);
CPU_SET(2, &mask);
result = sched_setaffinity(0, sizeof(mask), &mask);

(0 for the first parameter means the current process, supply a PID if it's some other process you want to control).

Answer 2

Use sched_setaffinity at the process level, or pthread_attr_setaffinity_np for individual threads.

Answer 3

In short

unsigned long mask = 7; /* processors 0, 1, and 2 */
unsigned int len = sizeof(mask);
if (sched_setaffinity(0, len, &mask) < 0) {
    perror("sched_setaffinity");
}

Look in CPU Affinity for more details