Sebastian Andersson wrote: > On Sat, Mar 25, 2006 at 01:00:59AM -0800, Mark Wedel wrote: >> For other reasons, I still think I'll add animation support to the map2 >> command. However, I think it also worthwhile to add something like: >> >> S->C: compress <data> > > I've got some experience in this, having implemented it in a mud > (DUMII) and I suggest a different approach. Have the zlib stream as a > layer between the socket and the server/client when it is turned on > and start it like this:
There are a few likely differences which may or may not effect crossfire in different ways: 1) Some data crossfire sends is just not compressible. The PNG data comes to mind - trying to compress it is at best a waste of time, and at worse, increases amount of data being transmitted. The other problem related to this is you'll often need to send a bunch of image data at one time (player changes to new map), and now there is lots of data you are trying to compress - the time it takes to compress that much data could become significant. 2) Latency is a big concern in crossfire, so we really can't add any. This means that for each and every tick, we need to make sure we send all the data we have - in lots of cases, this is going to be small data that doesn't compress well, so once again, a waste of cpu time (while this may seem trivial, there are certainly times when the server does become cpu bound) 3) The fact that crossfire does queue up data would allow for compressing at a higher level (basically, not have send_with_handling actually send data, but queue it up, and then at the end of the tick, compress the data). In that way, we can combine several small commands into a larger packet, but still not spend time compressing non compressible data. But doing that adds a fair amount of complication - a complete re-write of the socket code would probably be needed to reasonable support that. while adding a 'compress' prefix (it could be shortened to just gz, so now only adding a few bytes), by selectively compressing the big payloads is a very easy mechanism to do right now without any real downsides. _______________________________________________ crossfire mailing list [email protected] http://mailman.metalforge.org/mailman/listinfo/crossfire
