Example of concurrent processusing Python builtin library(example modified from example in Python docs)

concurrent_example.py

#!/usr/bin/env python
import os
from concurrent.futures import ProcessPoolExecutor
import math

import time

PRIMES = [
    112272535095293,
    112582705942171,
    112272535095293,
    115280095190773,
    115797848077099,
    1099726899285419]

def is_prime(n):
    if n % 2 == 0:
        return False

    sqrt_n = int(math.floor(math.sqrt(n)))
    for i in range(3, sqrt_n + 1, 2):
        if n % i == 0:
            return False
    return True


def time_taken(func):
    def wrapper():
        start = time.time()
        func()
        stop = time.time()
        return (stop - start)
    return wrapper

@time_taken
def main():
    with ProcessPoolExecutor() as executor:
        for number, prime in zip(PRIMES, executor.map(is_prime, PRIMES)):
            print('%d is prime: %s' % (number, prime))


@time_taken
def main2():
    for number in PRIMES:
        prime = is_prime(number)
        print('%d is prime: %s' % (number, prime))


if __name__ == '__main__':
    start = time.time()
    span1 = main()
    span2 = main2()
    
    print('1st: %.4f' % span1)
    print('2nd: %.4f' % span2)
    pct_savings = (span2 - span1) / span2
    print('SAVING: %.3f' % (pct_savings * 100))
    print('CPU count: %d' % os.cpu_count())