# -*- coding: utf-8 -*-

__author__ = "YuDian"

'''

    multiprocessing->Pool进程池。

    file name:13.py

'''

from multiprocessing import Pool

import os, time, random

def long_time_task(name):

    print('Run task %s (%s)...' % (name, os.getpid()))

    start = time.time()

    time.sleep(random.random() * 3)

    end = time.time()

    print('Task %s runs %0.2f seconds.' % (name, (end - start)))

if __name__ == '__main__':

    print('Parent process %s.' % os.getpid())

    print('父进程的父进程：（也就是打开这个文件的进程)：',os.getppid())

    p = Pool(9)     # pool()可以指定同时运行的进程数。如果缺省，默认为该电脑的CPU核数。如果赋值超过CPU核数，按照CPU核数。

    for i in range(11):    # range()内的范围可以任意指定，为运行的进程总数。

        p.apply_async(long_time_task, args=(i,))

    print('Waiting for all subprocesses done...')

    p.close()

    p.join()

    print('All subprocesses done.')

 import subprocess

 import os

 '''

     开一个子进程，并对子进程通信。参考：http://blog.csdn.net/seetheworld518/article/details/48805261

 file name:14.py

 '''

 class Shell(object):

     def runCmd(self, cmd):

         res = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)

         print('本程序的进程2：',os.getpid())

         print('用res.pid得到的就是这个的子进程，也就是13.py的父进程',res.pid)

         sout, serr = res.communicate('13.py\n')

         print('本程序的进程3：',os.getpid())

         return res.returncode, sout, serr, res.pid

 print('本程序的进程1：',os.getpid())

 shell = Shell()

 result=shell.runCmd('python F:/python_codes/learn_python_of_simple_codes/demos/13.py')

 print(result[1].decode('utf-8'))

本程序的进程1： 13928

本程序的进程2： 13928

用res.pid得到的就是这个的子进程，也就是13.py的父进程 6908

本程序的进程3： 13928

Parent process 8720.

父进程的父进程：（也就是打开这个文件的进程)： 6908

Waiting for all subprocesses done...

Run task 0 (15352)...

Run task 1 (7832)...

Run task 2 (11824)...

Run task 3 (3140)...

Run task 4 (12572)...

Run task 5 (18808)...

Run task 6 (9284)...

Run task 7 (17996)...

Run task 8 (1996)...

Task 5 runs 0.33 seconds.

Run task 9 (18808)...

Task 6 runs 0.63 seconds.

Run task 10 (9284)...

Task 7 runs 1.27 seconds.

Task 10 runs 0.90 seconds.

Task 2 runs 2.32 seconds.

Task 9 runs 2.07 seconds.

Task 0 runs 2.46 seconds.

Task 1 runs 2.47 seconds.

Task 4 runs 2.51 seconds.

Task 3 runs 2.58 seconds.

Task 8 runs 2.82 seconds.

All subprocesses done.