I have a gigantic difference in execution time between the two. Also, you can have the same behavior importing contextlib.closing; from multiprocessing imp

I have a gigantic difference in execution time between the two. Also, you can have the same behavior importing contextlib.closing; from multiprocessing import Pool from contextlib import closing with closing(Pool(15)) as p p.map(f, myiterable) takes <30 sec vs from concurrent.futures import ThreadPoolExecutor as Pool with Pool(15) as p p.map(f, myiterable) that takes > 1min. whereas ProcessPoolExecutor hangs, and I've no clue why.