PoC to demonstrate Copy-on-Write

a.py

bigobj = range(int(10e6))
print "waiting..."


def child():
    print "waiting inside child"
    time.sleep(10)

from multiprocessing import Process

p = Process(target=child, args=())
raw_input("press enter to start child")
p.start()
p.join()
print "quitting"

b.py

bigobj = range(int(10e6))
print "waiting..."


def child():
    print "waiting inside child"
    import time
    #### modify `bigobj` #######
    for i in xrange(len(bigobj)):
        bigobj[i] += 1
    ############################
    time.sleep(10)

from multiprocessing import Process

p = Process(target=child, args=())
raw_input("press enter to start child")
p.start()
p.join()
print "quitting"