Good language to develop a game server in?

Question

I was just wondering what language would be a good choice for developing a game server to support a large (thousands) number of users? I dabbled in python, but realized that it would just be too much trouble since it doesn't spawn threads across cores (meaning an 8 core server=1 core server). I also didn't really like the language (that "self" stuff grossed me out).

I know that C++ is the language for the job in terms of performance, but I hate it. I don't want to deal with its sloppy syntax and I like my hand to be held by managed languages. This brings me to C# and Java, but I am open to other languages. I love the simplicity of .NET, but I was wondering if, speed wise, this would be good for the job. Keep in mind since this will be deployed on a Linux server, it would be running on the Mono framework - not sure if that matters. I know that Java is syntax-wise very similar to .Net, but my experience with it is limited. Are there any frameworks out there for it or anthing to ease in the development?

Please help me and my picky self arrive on a solution.

UPDATE: I didn't mean to sound so picky, and I really don't think I was. The only language I really excluded was C++, Python I don't like because of the scalability problem. I know that there are ways of communicating between processes, but if I have an 8 core server, why should I need to make 8 processes? Is there a more elegant solution?

Answer 1

You could take a look at Stackless Python. It's an alternative Python interpreter that provides greater support for concurrency. Both EVE Online's server and client software use Stackless Python.

Disclaimer: I haven't used Stackless Python extensively myself, so I can't provide any first-hand accounts of its effectiveness.

Answer 2

Erlang is a language which is designed around concurrency and distribution over several servers, which is perfect for server software. Some links about Erlang and game-servers:

http://www.devmaster.net/articles/mmo-scalable-server/

http://www.erlang-consulting.com/euc2005/mmog/mmog_in_erlang.htm

I'm thinking of writing a game-server in Erlang myself.

Answer 3

Speaking of pure performance, if you can run Java 6 you get about 1:1 performance when compared to optimized C++ (special cases notwithstanding, sometimes Java is faster, sometimes C++), the only problem you will have is of course stuff like database libraries, interconnectivity, scalability and such. I believe there's a variety of good to great solutions available to each of these problems but you won't find one language which would solve everything for you so I have to give you the age old advice: Choose the language you like and use that one.

Oh, you're still reading this? :) Well, here's some extra pointers.

• EVE Online uses Python for its client and server side code and it's both bug-ridden and laggy as something I don't think I should write here so that'd be an example of how Python can be extended to (poorly) serve vast amounts of users.
• While Java has some good to great solutions to various related problems, it's really not the best language out there for vast amount of users; it doesn't scale well to extremes without tuning. However there's multi-VM solutions to this which somewhat fix the issue, for example Terracotta is said to do the job well.
• While C++ is rather cumbersome, it allows for such a low-level interaction with the system that you may actually find yourself doing things you thought you couldn't do. I'm thinking of something like dynamic per-core microclustering of runtime code blocks for "filling" every possible clock cycle of the processor as efficiently as possible for maximum performance and things like that.
• Mono is far behind the .NET VM/equivalent on Windows platforms so you wouldn't be able to use the latest and fanciest features of C#. However Windows XP (x64) OEM licenses are so laughably cheap at the moment that with small investment you could get a bunch of those and you could then run your code on the platform it was meant to be. And don't fall into the Linux hype, Linux is your saviour only if you really know how to use it and especially XP is pretty damn fast and stable nowadays.

Answer 4

I might be going slightly off-topic here, but the topic interests me as I have (hobby-wise) worked on quite a few game servers (MMORPG servers) - on others' code as well as mine. There is literature out there that will be of interest to you, drop me a note if you want some references.

One thing that strikes me in your question is the want to serve a thousand users off a multithreaded application. From my humble experience, that does not work too well. :-)

When you serve thousands of users you want a design that is as modular as possible, because one of your primary goals will be to keep the service as a whole up and running. Game servers tend to be rather complex, so there will be quite a few show-stopping bugs. Don't make your life miserable with a single point of failure (one application!).

Instead, try to build multiple processes that can run on a multitude of hosts. My humble suggestion is the following:

• Make them independent, so a failing process will be irrelevant to the service.
• Make them small, so that the different parts of the service and how they interact are easy to grasp.
• Don't let users communicate with the gamelogic OR DB directly. Write a proxy - network stacks can and will show odd behaviour on different architectures when you have a multitude of users. Also make sure that you can later "clean"/filter what the proxies forward.
• Have a process that will only monitor other processes to see if they are still working properly, with the ability to restart parts.
• Make them distributable. Coordinate processes via TCP from the start or you will run into scalability problems.
• If you have large landscapes, consider means to dynamically divide load by dividing servers by geography. Don't have every backend process hold all the data in memory.

I have ported a few such engines written in C++ and C# for hosts operating on Linux, FreeBSD and also Solaris (on an old UltraSparc IIi - yes, mono still runs there :). From my experience, C# is well fast enough, considering on what ancient hardware it operates on that sparc machine.

The industry (as far as I know) tends to use a lot of C++ for the serving work and embeds scripting languages for the actual game logic. Ah, written too much already - way cool topic.

Answer 5

You could as well use Java and compile the code using GCC to a native executable.

That way you don't get the performance hit of the bytecode engine (Yes, I know - Java out of the box is as fast as C++. It must be just me who always measures a factor 5 performance difference). The drawback is that the GCC Java-frontend does not support all of the Java 1.6 language features.

Another choice would be to use your language of choice, get the code working first and then move the performance critical stuff into native code. Nearly all languages support binding to compiled libraries.

That does not solve your "python does not multithread well"-problem, but it gives you more choices.

Answer 6

What kind of performance do you need?

twisted is great for servers that need lots of concurrency, as is erlang. Either supports massive concurrency easily and has facilities for distributed computing.

If you want to span more than one core in a python app, do the same thing you'd do if you wanted to span more than one machine — run more than one process.