问题
I am designing an simulator application where the application launches multiple socket connection(around 1000 connections) to a server. I don't want to launch as many as threads to handle those connections, since the system cant handle that much clients. Using Select doesnt make sense, since i need to loop through 1000 connections which may be slow. Please suggest me how to handle this scenario.
回答1:
You want to be using asynchronous I/O with an I/O Completion Port (IOCP).
It's too much to explain shortly, but any Windows application that needs to support a large number of concurrent sockets should be using an IOCP.
An IOCP is essentially an Windows-provided thread safe work queue. You queue a 'completion packet' to an IOCP and then another thread dequeues it and does work with it.
You can also associate many types of handles that support overlapped operations, such as sockets, to an IOCP. When you associate a handle with an IOCP, overlapped operations such as WSARecv will automatically post a completion packet to the associated IOCP.
So, essentially, you could have one thread handling all 1000 connections. Each socket will be created as an overlapped socket and then associated with your IOCP. You can then call WSARecv on all 1000 sockets and wait for a completion packet to become available. When data is received, the operating system will post a completion packet to the associated IOCP. This will contain relevant information, such as how much data was read and the buffer containing the data.
回答2:
Looping through 1000 handles is still significantly faster than sending 1000 packets, so I wouldn't worry about performance here. select() is still the way to go.
来源：https://stackoverflow.com/questions/5468519/multiple-socket-client-connecting-to-a-server