多任务进程池

 1 # -*- coding:utf-8 -*-
 2 from multiprocessing import Pool
 3 import os,time,random
 4 
 5 
 6 def worker(msg):
 7     t_start = time.time()
 8     print("%s开始执行" % (msg))
 9     # print("进程号是：%d" % os.getpgid())
10     # random.random()随机生成0-1之间的浮点数
11     time.sleep(random.random()*2)
12     t_stop = time.time()
13     print(msg,"执行完毕，耗时%.2f" % (t_stop-t_start))
14 
15 
16 # worker(1)
17 def main():
18     # 定义一个进程池，最大进程为3
19 
20     po = Pool(3)
21     for i in range(0,10):
22         # Pool().apply_async(要调用的目标，（以元祖的形式传递给目标的参数，）)
23         # 每次循环将会用空闲出来的子进程去调用目标
24         po.apply_async(worker,(i,))
25 
26     print("----------start------------")
27     po.close()  # 关闭进程池，关闭后po不再接受新的请求
28     po.join()  # 等带po中所有子进程执行完成，必须放在close语句之后
29     print("----------end------------")
30 
31 
32 if __name__ == ‘__main__‘:
33     main()