async_cpu_bound.py

import time
import asyncio
from concurrent import futures


def primes(num):
    rv = []
    p = [0] * num
    k, n = 0, 2
    print("start time:", time.time())
    while k < num:
        i = 0
        while i < k and n % p[i] != 0:
            i += 1
        if i == k:
            p[k] = n
            k += 1
            rv.append(n)
        n += 1
    print("end time:", time.time())
    return rv


def main():
    loop = asyncio.get_event_loop()
    executor = futures.ProcessPoolExecutor()
    start = time.time()
    futs = []
    for i in range(3):
        futs.append(loop.run_in_executor(executor, primes, 5000))
    done = loop.run_until_complete(asyncio.wait(futs))
    end = time.time()
    print("processing time:", end - start)
    print(done)

if __name__ == '__main__':
    main()