Test parallelism in python

parallelism.py

"""Test parallelism in python.

$ \time -f "%e s - %P" python3 par.py 1 > /dev/null
6.74 s - 100%
$ \time -f "%e s - %P" python3 par.py 4 > /dev/null
1.87 s - 385%
$ bc -l <<< "6.74/1.87"
3.60...
"""

import sys
from concurrent.futures import ProcessPoolExecutor


def solve(x):

    def slow_pow(a, b, m, r=1):
        for _ in range(b):
            r *= a
            r %= m
        return r

    return slow_pow(x, 10**7, 982451653)


def main():
    max_workers = int(sys.argv[1])
    with ProcessPoolExecutor(max_workers) as executor:
        for result in executor.map(solve, range(100, 108)):
            print(result)


if __name__ == '__main__':
    main()