socket编程的select poll和epoll这两种机制，本质区别在哪里？

Posted 2023-04-02

如题，谢谢！

参考技术A 例如你在大学中读书,要等待一个朋友来访,而这个朋友只知道你在H号楼,但不知道你在哪一个房间（例如H号楼有200个寝室），select/poll()模型(也就是多路复用模型)，比如你的同学来了,select/poll比较笨,她带着你朋友挨个房间进行查询谁是同学你,找到你后，说你的朋友来了，epoll是poll的改进，他相当于登记了每个宿舍住的人的姓名，你的朋友到了H栋楼的门口，epoll(管理员)会问他，你找谁，你的朋友把你的名字一说，管理员查到你的房间号后，直接把他带到你的房间，区别就是这样，希望能帮到你！

select —— poll —— epoll

import socket,select
s=socket.socket()
s.setblocking(False)
s.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
s.bind((‘127.0.0.1‘,6666))
s.listen()
rlist=[s,]
wlist=[]
erlist=[]
while True:
    rs,ws,er=select.select(rlist,wlist,erlist)
    print(1)
    for i in rs:
        if i is s:
            con,add=s.accept()
            rlist.append(con)
        else:
            date=i.recv(1024)
            if not date:
                rlist.remove(i)
            print(date.decode())
            i.send(date)
    for i in erlist:
        print(i)

View Code ——select 服务端

import socket,select,time
s=socket.socket()
s.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
s.bind((‘127.0.0.1‘,6666))
s.listen()
poll=select.poll()
poll_dic={s.fileno(): s,}
poll.register(s, select.POLLIN | select.POLLERR)
while True:
    try:
        events=poll.poll()
        for fd,event in events:
            print(fd,event)
            if fd == s.fileno():
                con,add=s.accept()
                poll_dic[con.fileno()] = con
                poll.register(con,select.POLLIN | select.POLLERR)
            elif event == select.POLLIN:

                date = poll_dic[fd].recv(1024)
                print(date.decode())
                if not date:
                    print(‘进来了‘)
                    poll.unregister(fd)
                    poll_dic[fd].close()
                    del poll_dic[fd]

    except:
        poll.unregister(s)

View Code ——poll 服务端

import socket,select
s=socket.socket()
s.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
s.bind((‘127.0.0.1‘,6666))
s.listen()
poll=select.poll()
poll_dict={s.fileno():s}
def a(fd):
    poll.unregister(fd)
    poll_dict[fd].close()
    del poll_dict[fd]

def main():
    poll.register(s,select.POLLIN | select.POLLERR)
    while True:
        p=poll.poll()
        for fd,event in p:
            if fd == s.fileno():
                con, addr = s.accept()
                poll.register(con, select.POLLIN | select.POLLERR)
                poll_dict[con.fileno()]=con
            elif event == select.POLLIN:
                date=poll_dict[fd].recv(1024)
                if not date:
                    a(fd)
                    continue
                print(date.decode(),111)
                poll_dict[fd].send(date)
            elif event == select.POLLERR:
                a(fd)
if __name__ == ‘__main__‘:
    main()

View Code ——POLL加一服务端

 

import socket,selectors
s=socket.socket()
s.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
s.bind((‘127.0.0.1‘,6666))
s.listen()
epoll=selectors.DefaultSelector()
def accept_(s):
    con,addr=s.accept()
    epoll.register(con,selectors.EVENT_READ,recv_)

def recv_(con):
    try:
        date=con.recv(1024)
        if not date:
            raise ‘‘
        print(date.decode())
        con.send(date)
    except:
        epoll.unregister(con)
        con.close()
        print(‘断开连接‘)

def main():
    epoll.register(s,selectors.EVENT_READ,accept_)
    while True:
        s_eoll=epoll.select()
        for key,event in s_eoll:
            ac=key.data   #这是文件指针accept_
            print(key,‘这是KEY‘)
            ac(key.fileobj)
if __name__ == ‘__main__‘:
    main()

View Code