python实现启动一个外部程序,并且不阻塞当前进程

#!/usr/bin/env python
# coding:UTF-8 
 
"""
@version: python3.x
@author:曹新健
@contact: 617349013@qq.com
@software: PyCharm
@file: 5.启动大量子进程.py
@time: 2018/9/18 22:28
""" 
from multiprocessing import Process,Pool
import time,os,random
 
def run(num):
 print("子进程%d启动---%s" % (num,os.getpid()))
 start = time.time()
 time.sleep(random.choice([1,2,3]))
 end = time.time()
 #print(end)
 print("子进程%d结束---%s---耗时%.2f" % (num, os.getpid(),end-start))
 
if __name__ == "__main__":
 print("父进程启动")
 #创建进程池,Pool默认为CPU核心数
 pp = Pool()
 for i in range(8):
  #创建进程，放入进程池统一管理
  result = pp.apply_async(run,args=(i,))
 
 #进程池在调动join之前必须先调动close，调用close之后就不能再继续添加新的进程了
 pp.close()
 pp.join()
 
 print("父进程结束")