Performance

In high-traffic situations, performance of a server is usually limited by the network bandwidth or by the CPU usage of the server's higher layers. MUSES itself should not represent a performance bottleneck; nevertheless, there are some aspects of MUSES that must be taken into account during optimization.

There is little to do about incoming traffic. In many realistic cases, each client receives what every other client is sending. If this is true, the total output is proportional to the square of total input; as a consequence, when there are many connections open, incoming traffic has negligible effects when compared to outgoing traffic. Even if this is not the case, reading network input into your application is usually a straightforward process, unless you write a complicated ReceiveHandler.

From the point of view of reducing input-related workload, two things can be done:

• If you know the typical and maximum size of client input, provide this information to MUSES via Connection::setBufferSize(). Do not make the buffer too small, or you might even prevent the server from accepting client input.
• Optimize or reorganize your ReceiveHandler, if a profiler tells you it is a performance bottleneck.

Optimizing outgoing traffic is usually a better strategy, both because there is more to be gained, and because there are more efficient techniques. First of all, you may want to use a simple SendFilter (perhaps the default raw filter, if you're certain your server is not going to send IAC to a telnet client). Avoid frequent changes of the filter, unless they're really necessary.

More importantly, consider the overhead associated to each outgoing network packet. Sending a single 1000-byte packet is much more efficient than sending 1000 1-byte packets. Therefore, don't flush the output buffer unless you really need to. By the way, did you know that endl flushes the buffer? If you need to send a multi-line text, put a CR/LF in the text, rather than resorting to endl.

For more information, see your operating system documentation (try man setsockopt).

To summarize:

• Don't use endl when you don't need to flush
• Keep your SendFilter simple, and don't change it too often

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