并行

 并行需要多个cpu才能实现并行

一个cpu只能做到并发，多个cpu同时运行多个程序实现并行。

2个cpu开启两个进程：

# -*- coding: utf-8 -*-
import multiprocessing
import time


def now_time():
    return time.asctime(time.localtime(time.time()))


# process one
def run():  # 并行是模拟耗时任务，并发是模拟阻塞  !!
    print('one start:', now_time())
    time.sleep(5)
    print('one end:', now_time())


if __name__ == '__main__':
    process = multiprocessing.Process(target=run)
    process.start()
    # process two
    print('two start:', now_time())
    time.sleep(5)
    print('two end:', now_time())

two start: Thu Mar 28 15:45:14 2019
one start: Thu Mar 28 15:45:14 2019
two end: Thu Mar 28 15:45:15 2019
one end: Thu Mar 28 15:45:19 2019

多进程实现并行

# -*- coding: utf-8 -*-
''' 多进程实现并发'''
import socket
import multiprocessing


server = socket.socket()
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) # 释放端口
server.bind(('', 8888))
server.listen(1000) # 生成监听套接字


def server_recv(conn):
    while True:
        recv_data = conn.recv(1024)
        if recv_data:
            print(recv_data.decode())
            conn.send(recv_data)
        else:
            conn.close()
            break


while True:
    conn, addr = server.accept()  # 生成对等套接字
    # 将阻塞的对等套接字存入进程
    process = multiprocessing.Process(target=server_recv, args=(conn, ), daemon=True)
    process.start()