Question

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Bind threads to processors

In Linux, is it possible to fix threads to execute on certain cores. If that is possible, I also want to know if it is possible to execute one thread exclusively on a certain core, that is disallowing any other thread to execute on that core while that thread is executing.

Answer 1

That’s what pthread_setaffinity_np(3) does.

The pthread_setaffinity_np() function sets the CPU affinity mask of
the thread thread to the CPU set pointed to by cpuset. If the call is
successful, and the thread is not currently running on one of the CPUs
in cpuset, then it is migrated to one of those CPUs.

As an example:

cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(3, &set); /* Run only on the third CPU. */

pthread_setaffinity_np(thr, CPU_SETSIZE, &set);

You can also do it with sched_setaffinity(2) and gettid, but that manual page says:

If you are using the POSIX threads API, then use
pthread_setaffinity_np(3) instead of sched_setaffinity().