IO Model Consideration

By now you might be wondering how to choose the I/O model you should use when designing your application. As we've mentioned, each model has its strengths and weaknesses. All of the I/O models do require fairly complex programming when compared with developing a simple blocking-mode application with many servicing threads. We offer the suggestions below for client and server development.

Client development

When you are developing a client application that manages one or more sockets, we recommend using overlapped I/O or WSAEventSelect over the other I/O models for performance reasons. However, if you are developing a Windows-based application that manages window messages, the WSAAsyncSelect model might be a better choice because WSAAsyncSelect lends itself to the Windows message model, and your application is already set up for handling messages.

Server development

When you are developing a server that processes several sockets at a given time, we recommend using overlapped I/O over the other I/O models for performance reasons. However, if you expect your server to service a large number of I/O requests at any given time, you should consider using the I/O completion port model for even better performance.