Threading in Python using multiple cores

Question

As far as I know, Python's threading library uses POSIX threads for threading and it does not run on multiple cores. So is it possible that we implement a multicore threading system for Python threads using Open MP?

Answer 1

CPython ("default" Python implementation) is not utilizing multiple cores because of Global Interpreter Lock. So every Python statement has to hold that lock.

But modules that are written in C may release interpreter lock before time-consuming operation. I.e. numpy does that: http://wiki.scipy.org/ParallelProgramming

They have handy example for that:

import numpy as np
import math

def f(x):
    print x
    # This statements hold GIL and cannot be run
    # in two parallel threads 
    y = [1]*10000000
    [math.exp(i) for i in y]

def g(x):
    print x
    # This statements fall to NumPy C code
    # than release GIL and can be multithreaded
    y = np.ones(10000000)
    np.exp(y)

Since OpenMP is also a tool for C, I think that is what you seek for.