pythreads.py

# seq.py
import time

def countdown(n):
	while n > 0:
		n -= 1

COUNT = 50000000
start = time.time()
countdown(COUNT)
end = time.time()

print(end-start)


# par.py
from threading import Thread
import time

def countdown(n):
    while n > 0:
        n -= 1

COUNT = 50000000

t1 = Thread(target=countdown, args=(COUNT/2,))
t2 = Thread(target=countdown, args=(COUNT/2,))

start = time.time()
t1.start(); t2.start()
t1.join(); t1.join()
end = time.time()

print(end-start)


# spin.py
# spin uselessly
while True:
    pass


# parspin.py
from threading import Thread
from subprocess import Popen
import time

def countdown(n):
    while n > 0:
        n -= 1

COUNT = 50000000

p = Popen(['python','spin.py'])
t1 = Thread(target=countdown, args=(COUNT/2,))
t2 = Thread(target=countdown, args=(COUNT/2,))

start = time.time()
t1.start(); t2.start()
t1.join(); t1.join()
end = time.time()
p.terminate()

print(end-start)