Threading in Python

threading.py

# Testing of how threading works
# https://www.youtube.com/watch?v=ecKWiaHCEKs
"""
Threading:
- A new thread is spawned within the existing process
- Starting a thread is faster than starting a process
- Memory is shared between all threads
- Mutexes often necessary to control access to shared data
- One GIL (Global Interpreter Lock) for all threads
"""
from threading import Thread
import os
import math


def calc(num):
    for i in range(0, 7000000):
        math.sqrt(i)


def main():
    threads = []
    for i in range(os.cpu_count()):
        print('Thread: %d' % i)
        threads.append(Thread(target=calc, args=(40456654,)))

    for thread in threads:
        thread.start()

    for thread in threads:
        thread.join()

    print('\n\nDone!')


if __name__ == "__main__":
    main()