Multiprocessing.Pool makes Numpy matrix multiplication slower

Question

So, I am playing around with multiprocessing.Pool and Numpy, but it seems I missed some important point. Why is the pool version much

Answer 1

Your code is correct. I just ran it my system (with 2 cores, hyperthreading) and obtained the following results:

$ python test_multi.py 
30.8623809814
19.3914041519

I looked at the processes and, as expected, the parallel part showing several processes working at near 100%. This must be something in your system or python installation.