Checkpoint synchronization: Difference between revisions

=={{header|Python}}==

<lang Python>

"""

Based on https://pymotw.com/3/threading/

"""

import threading

import time

import random

def worker(workernum, barrier):

# task 1

sleeptime = random.random()

print('Starting worker '+str(workernum)+" task 1, sleeptime="+str(sleeptime))

time.sleep(sleeptime)

print('Exiting worker'+str(workernum))

barrier.wait()

# task 2

sleeptime = random.random()

print('Starting worker '+str(workernum)+" task 2, sleeptime="+str(sleeptime))

time.sleep(sleeptime)

print('Exiting worker'+str(workernum))

barrier = threading.Barrier(3)

w1 = threading.Thread(target=worker, args=((1,barrier)))

w2 = threading.Thread(target=worker, args=((2,barrier)))

w3 = threading.Thread(target=worker, args=((3,barrier)))

w1.start()

w2.start()

w3.start()

</lang>

Output:

<pre>

Starting worker 1 task 1, sleeptime=0.26685336937182835

Starting worker 2 task 1, sleeptime=0.947511912308323

Starting worker 3 task 1, sleeptime=0.6495569605252262

Exiting worker1

Exiting worker3

Exiting worker2

Starting worker 2 task 2, sleeptime=0.5585479798026259

Starting worker 3 task 2, sleeptime=0.4104925281220747

Starting worker 1 task 2, sleeptime=0.15963562165203105

Exiting worker1

Exiting worker3

Exiting worker2

</pre>