yet another confusion with multiprocessing error, ‘module’ object has no attribute ‘f’

Restructure your code so that the f() function is defined before you create instance of Pool. Otherwise the worker cannot see your function.

#!/usr/bin/python
# -*- coding: utf-8 -*-

from multiprocessing import Pool

def f(x):
    return x*x

p = Pool(1)
p.map(f, [1, 2, 3])