在python中同时运行两个进程

Question

import multiprocessing as mp .   
from multiprocessing import Process, Queue, Manager .   
from threading import Thread .   
from subprocess import Popen, PIPE, STDOUT .  
count = 0   
def loop1():  
while True:
for i in range(0, 100): 
count = count + 1 . 
time.sleep(2)
if count == 100:
count = 0

def worker(filename):  
proc = Popen(["{0}".format(filename)], stdout=PIPE, stderr=STDOUT, shell=True)
(proc.communicate()[0])

def loop2():
while True:  
for i in ["a.py", "b.py"]:  
if count == 50:  
# run some executable in background and do not wait for it . 
p = Process(target=worker, args=(i)) . 
a.sleep(2)   

if __name__ == '__main__':  
T1 = Thread(target=loop1, args=()) 
T2 = Thread(target=loop2, args=()) 
T1.start() . 
T2.start() . 
#T1.join() . 
#T2.join()

1( 我应该如何并行启动两个方法？我需要检查方法2中方法1的变量状态？T1.start((和T2.start。

2( loop2的任务必须在50秒后再次运行。

Answer 1

您需要使用Event来同步进程。对于多处理，这两个进程都将在一个单独的python实例中启动，因此它应该会给您很好的时间。看看下面的代码：

from multiprocessing import Process, Event
import os
import time

def task(event, rerun=None):
proc_id = os.getpid()
event.wait()  # Wait for an event
print('timestamp of process id {}: {}'.format(proc_id, time.time()))
if rerun is not None:
time.sleep(rerun)
print('timestamp of process id {}: {}'.format(proc_id, time.time()))

if __name__ == '__main__':
e = Event()  # Create event that will be used for synchronization
p1 = Process(target=task, args=(e,))
p1.start()

# Start second task with rerun after 2 seconds
p2 = Process(target=task, args=(e, 2))
p2.start()
e.set()  # Set event so all processes can start at the same time

这将产生这样的输出：

timestamp of process id 28415: 1542278592.7580822
timestamp of process id 28416: 1542278592.7585154
timestamp of process id 28416: 1542278594.7604039

至于其他事情，只需玩这个代码