Day15-python Basic 15 Module Learning-selectors

The content of this section

1:python/selectors Module

2:selsect instances

1:python/selectors Modules and queues

The selectors module is an IO multiplexing mechanism that can be implemented:

It has a platform to choose the best IO multipath mechanism, such as on the win system he default is the Select mode and on Linux it default epoll.

Common IO multiplexing is divided into three types: Select, poll, Epoll, and only select is supported on Windows, while Linux supports

Disadvantages of Select:

1, each call will be all the file descriptor (FD) copy of the kernel space, resulting in efficiency degradation

2. Traverse all file descriptors (FD) to see if there is any data access

3. Maximum number of links (1024)

Poll

It is the transition phase of select and Epoll, which has no limit on the maximum number of links

Epoll:

1. The first function is to create a epoll handle that copies all descriptors (FD) to the kernel space, but copies it only once.

2, the callback function, a function or an action after the successful completion of the function will be triggered for all descriptors (FD) binding a callback function, once the data access is triggered by the callback function, the callback function will (FD) placed in the list

3. function to determine whether the linked list is empty

4. No limit on Maximum startup item

2:selsect instances:

1 ## #服务端 ################2 3 ImportSelectors#IO multiplexing based on the Select module, it is recommended that you use4 ImportSocket5sock=Socket.socket ()6Sock.bind (('127.0.0.1', 8800))7Sock.listen (5)8 sock.setblocking (False)9Sel=selectors. Defaultselector ()#Choose the best IO multiplexing mechanism based on the platform, e.g. Linux will choose EpollTen  One defRead (conn,mask): A     Try: -DATA=CONN.RECV (1024) -         Print(Data.decode ('UTF8')) theData2=input ('>>>>') -Conn.send (Data2.encode ('UTF8')) -     exceptException: - Sel.unregister (conn) +  - defAccept (sock,mask): +Conn,addr=sock.accept () A     Print('-------', conn) at Sel.register (conn,selectors. Event_read,read) -  -Sel.register (sock, selectors. Event_read, accept)#registration function, once the reaction continues to execute down -  -  whileTrue: -     Print('wating ....') inEvents=sel.select ()#The Listener Object [(sock), (), ()] of the event and select is monitored -  to      forKey,maskinchEvents: +         #print (key.data) #accept Find the active binding function -         #print (key.fileobj) #sock Find the active file descriptor the  *Func=Key.data $obj=Key.fileobjPanax Notoginseng  -Func (Obj,mask)#1 Accept (Sock,mask) 2read (conn,mask) the  + ##客户端 ################# A ImportSocket thetin=Socket.socket () +Tin.connect (('127.0.0.1', 8800)) -  whileTrue: $Inp=input ('>>>>') $Tin.send (Inp.encode ('UTF8')) -DATA=TIN.RECV (1024) -     Print(Data.decode ('UTF8'))

Day15-python Basic 15 Module Learning-selectors