Python: Threading inside of a Multiprocess?

Question

I am trying to use the multiprocess module to parallelize my program.

Specifically, I am trying to achieve:

for i in range(something):
    p = multiprocess.Process(target=worker, args=(...))
    etc....

def worker(...):
    for i in range(something):
        make some system call and check for timeout

For the last line, I want to use threading, since subprocess can't support timeout checking, but I was wondering how GIL will affect the fact that they are running in processes spawned by multiprocess - i.e. will GIL kill the parallelization achieved through multiprocess by restricting each thread to run in one core.