Issue with Python's Multiprocessing in Google Colab

Question

I need to do some multiprocessing with my Python scripts and I decided to give it a try with Google's collaboratory.

I've connected to local runtime and tried to run the following script:

import multiprocessing

def spawn(num):
  print('Spawned! {}'.format(num))

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

However, when I run this, nothing happens. Absolutely nothing, no errors, no prints, it just executes instantly and that's it.

Am I missing something? Does multiprocessing work with Google Colab local runtime?

Thanks in advance.

Answer 1

Run this instead

import multiprocessing
def spawn(num):
  print('Spawned! {}'.format(num))

for i in range(5):
  p = multiprocessing.Process(target=spawn, args=(i,))
  p.start()