Python学习-day10 进程

学习完线程，学习进程

进程和线程的语法有很多一样的地方，不过在操作系统中的差别确实很大。

模块是threading 和 multiprocessing

多进程multiprocessing

multiprocessing is a package that supports spawning processes using an API similar to the threading module. The multiprocessing package offers both local and remote concurrency, effectively side-stepping the Global Interpreter Lock by using subprocesses instead of threads. Due to this, the multiprocessing module allows the programmer to fully leverage multiple processors on a given machine. It runs on both Unix and Windows.

如何启动多进程

#Authon Ivor

from multiprocessing import Process

import os

def info(title):

    print(title)

    print('module name:', __name__)

    print('parent process:', os.getppid())

    print('process id:', os.getpid())

    print("")

def f(name):

    info('\033[31;1mfunction f\033[0m')

    print('hello', name)

if __name__ == '__main__':

    info('\033[32;1mmain process line\033[0m')

    p = Process(target=f, args=('bob',))

    p.start()

    p.join()

进程间通信的三种方式

Queue

#Author:Ivor

from multiprocessing import Process,Queue

import os

# threading.queue.Queue()

def run(q):

    q.put("---in the Child process---")

    print("parent_pid:",os.getppid())

    print("current_pid:",os.getpid())

    print("------------------")

if __name__ == '__main__':

    q = Queue()

    print("---main process---")

    print("parent_pid:",os.getppid())

    print("current_pid:",os.getpid())

    print("------------------")

    p = Process(target=run,args=(q,))

    p.start()

    print(q.get())

    p.join()

Pipe

#Author:Ivor

from multiprocessing import Process,Pipe

def run(conn):

    conn.send("from child")

    conn.close()

if __name__ == '__main__':

    parent_conn,child_conn = Pipe()

    p = Process(target=run,args=(child_conn,))

    p.start()

    print(parent_conn.recv())

    p.join()

Manager

#Author:Ivor

from multiprocessing import Process,Manager

import os

def run(d,l):

    d[os.getpid()] = os.getpid()

    l.append(os.getpid())

    print(l)

pro_list = []

if __name__ == '__main__':

    manager = Manager()

    d = manager.dict()

    l = manager.list()

    for i in range(10):

        p = Process(target=run,args=(d,l))

        pro_list.append(p)

        p.start()

    for i in pro_list:

        i.join()

    print(d)

    print(l)

进程池的概念

Pool

#Authon Ivor

from multiprocessing import Process,Pool

import time,os

def run(n):

    print("Process %s is running.." % n)

    time.sleep(1)

    return os.getpid()

def bar(arg):

    print("exec done---",arg)

result = []

if __name__ == '__main__':

    pool = Pool(processes=2)

    for n in range(10):

        result.append(pool.apply_async(func=run,args=(n,),callback=bar))

    for res in result:

        print("res---",res.get())

    pool.close()

    pool.join()