CODEWITHSUNDEEP
pythonmultiprocessing
zell
zell

Reputation: 10204

Why my processes are executed in a sequential order?

I am playing with Python's multiprocessing module. I started with this program:

import multiprocessing

def worker(num):
    """thread worker function"""
    print 'Worker:', num
    return

if __name__ == '__main__':
    for i in range(5):
        p = multiprocessing.Process(target=worker, args=(i,))
        p.start()

To my surprise, the results are always this:

Worker: 0
Worker: 1
Worker: 2
Worker: 3
Worker: 4

I would expect that the workers are output in a different order from time to time, but that never happened no matter how many times I run the program. Where did I misunderstand?

Upvotes: 0

Views: 213

Answers (1)

Reut Sharabani
Reut Sharabani

Reputation: 31339

Your code is fine, its just very fast. Try this to add some jittering:

import multiprocessing
from random import randint
from time import sleep

def worker(num):
    """thread worker function"""
    sleep(randint(0, 5))
    print 'Worker:', num
    return

if __name__ == '__main__':
    for i in range(5):
        p = multiprocessing.Process(target=worker, args=(i,))
        p.start()

Upvotes: 1

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