Question

Application

I am working on an MMO and have run into an issue. The MMO server I’ve built is fast and locally sending messages to my game client every ~50 milliseconds on UDP sockets. Here is an example of a message from sever to client through my current message system:

count={2}body={[t={agt}id={42231}pos={[50.40142117456183,146.3123192153775]}rot={200.0},t={agt}id={4946}pos={[65.83051652925558,495.25839757504866]}rot={187.0}}

count={2}, 2 = number of objects
[,] = array of objects

I built a simple text parser, code: http://tinypaste.com/af3fb928

I use the message like :

    int objects = int.Parse(UTL.Parser.DecodeMessage("count", message));
    string body = UTL.Parser.DecodeMessage("body", message);
    for (int i = 0; i < objects; i++)
    {
        string objectStr = UTL.Parser.DecodeMessage("[" + i + "]", body);
        // parse objecStr with UTL.Parser.DecodeMessage to extract pos & rot and apply to objects
    )

Issue

When I have more objects ~ 60+ the performance dramatically decreases.

Question

What is standard method for packaging and reading message between clients and server in MMOs or real-time online games?

Answer 1

One of your problems might be unnecessary string instantiation. Any time you do a concatenation, split, or get a substring, you are creating new string instances on the stack, which are copied from the original string and need to be collected afterwards.

Try to change your code to iterate through the string character by character, and parse the data using the original string only. You should only use indexing, indexOf and possibly even write your own int and float parsers which accept a string offset + length to avoid creating substrings at all. I am not sure if this is overkill, but it’s not “premature” optimization if you have hard evidence that it works slow.

Also, did you try Protocol buffers? I believe their performance should be pretty good (just write a small console app for benchmark). Or with JSON, that’s a standard concise format (but I have no clue about how optimized Json.NET is). Nothing should usually beat a hard coded specialized parser in terms of performance, but with future maintenance in mind, I would try one of these protocols before anything else.