multiprocessing进程

import multiprocessing
import os

def worker1():
    # printing process id
    print("ID of process running worker1: {}".format(os.getpid()))
def worker2():
    # printing process id
    print("ID of process running worker2: {}".format(os.getpid()))

if __name__ == "__main__":
    # printing main program process id
    print("ID of main process: {}".format(os.getpid()))

    # creating processes
    p1 = multiprocessing.Process(target=worker1)
    p2 = multiprocessing.Process(target=worker2)

    # starting processes
    p1.start()
    p2.start()

    # process IDs
    print("ID of process p1: {}".format(p1.pid))
    print("ID of process p2: {}".format(p2.pid))

    # wait until processes are finished
    p1.join()
    p2.join()

    # both processes finished
    print("Both processes finished execution!")

    # check if processes are alive
    print("Process p1 is alive: {}".format(p1.is_alive()))
    print("Process p2 is alive: {}".format(p2.is_alive()))

multiprocessing进程池

import multiprocessing

# 例如
def download(i):
    try:
        print(i)
        os.chdir(path)
        os.system("you-get " + i)
    except:
        print('error ' + i)

url1_list = ['', '', '']


if __name__ == '__main__':
    pool = multiprocessing.Pool(processes = 4)  # 最多同时四个进程,多余cpu核心数反而浪费资源
    pool.map(download, url1_list)               #dowmload--需要执行的函数,url_list前个函数的参数列表---注意是列表---
    pool.close()  # 关闭进程池，不在接受新进程
    pool.join()   # 等待子进程结束