multiprocessing with Event

from multiprocessing.pool import Pool
from multiprocessing import Event

import time

EV = [Event() for e in xrange(11)]

def echo(i):
    EV[i].wait()
    time.sleep(0.001)
    EV[i+1].set()
    return i

def main():
    p = Pool(10)

    for e in EV: e.clear()
    EV[0].set()
    run1 = [a for a in p.imap_unordered(echo, xrange(10))]

    for e in EV: e.clear()
    EV[0].set()
    run2 = [a for a in p.imap_unordered(echo, xrange(10))]

    for e in EV: e.clear()
    EV[0].set()
    run3 = [a for a in p.imap_unordered(echo, xrange(10))]

    for e in EV: e.clear()
    EV[0].set()
    run4 = [a for a in p.imap_unordered(echo, xrange(10))]

    print( run1 == run2 == run3 == run4 )

if __name__ == '__main__':
    main()