Interaction between taskset and sched_setaffinity

Question

Could anyone tell me what would occur if I ran

taskset -c 7 ./fred.x

but then inside fred.x a thread is calling sched_setaffinity to bind to core 6?

Would that thread get ANY cpu time ever, or will it remain idle indefinitely?

Answer 1

taskset itself calls sched_setaffinity() and then execve to run your command. So this question boils down to "What happens if I call sched_setaffinity() twice in the same thread?" And the answer is, the second call overrides the first.

So in your specific example, the thread which calls sched_setaffinity() will indeed be bound to core 6, and it will be runnable.