Many threads or as few threads as possible?

Question

As a side project I\'m currently writing a server for an age-old game I used to play. I\'m trying to make the server as loosely coupled as possible, but I am wondering what

Answer 1

What's your platform? If Windows then I'd suggest looking at async operations and thread pools (or I/O Completion Ports directly if you're working at the Win32 API level in C/C++).

The idea is that you have a small number of threads that deal with your I/O and this makes your system capable of scaling to large numbers of concurrent connections because there's no relationship between the number of connections and the number of threads used by the process that is serving them. As expected, .Net insulates you from the details and Win32 doesn't.

The challenge of using async I/O and this style of server is that the processing of client requests becomes a state machine on the server and the data arriving triggers changes of state. Sometimes this takes some getting used to but once you do it's really rather marvellous;)

I've got some free code that demonstrates various server designs in C++ using IOCP here.

If you're using unix or need to be cross platform and you're in C++ then you might want to look at boost ASIO which provides async I/O functionality.