High performance TCP server in C#

Question

I am an experienced C# developer, but I have not developed a TCP server application so far. Now I have to develop a highly scalable and high performance server that can hand

Answer 1

It must be async, there is no way around this. High performance and scalability don't mix with one-thread-per-socket. You can have a look at what StackExchange themselves are doing, see async Redis await BookSleeve which leverages the CTP features from the next C# release (so is on the edge and subject to changes, but it is cool). For even more bleeding edge the solutions evolves around leveraging SocketAsyncEventArgs Class which takes things one step further by eliminating the frequent allocations of async handlers associated with 'classic' C# async processing:

The SocketAsyncEventArgs class is part of a set of enhancements to the System.Net.Sockets.Socket class that provide an alternative asynchronous pattern that can be used by specialized high-performance socket applications. This class was specifically designed for network server applications that require high performance. An application can use the enhanced asynchronous pattern exclusively or only in targeted hot areas (for example, when receiving large amounts of data).

Long story short: learn async or die trying...

BTW, if you're asking why async, then read the three articles linked from this post: High Performance Windows programs. The ultimate answer is: the underlying OS design requires it.