Yesterday, Guude pointed out the lack of available profiling tools for minecraft - it's very hard to pinpoint exactly what's causing lag.

Currently there are two solutions, and neither are easy:

• jvisualvm - Not easy enough to set up or understand what it tells you.
• TickThreading - the profiling tools work, but the rest of it is very buggy.

Obviously, this isn't ideal, so I've made a small mod called TickProfiler which is just the profiling part of TickThreading. This might not even be useful now, I'm not sure what setup the forgecraft guys will be using but it's likely that they have their own profiling tools which are at least as useful as this. If they're just using jvisualvm or yourkit this may still be useful.

Anyway, if anyone wants to test it it's available here. Just the GitHub project page, haven't got a proper site or a forum post anywhere yet.

And here's an example of the profiler output in game. Console output.

Haven't actually written documentation yet, so here's the quick version. /profile e to profile everything, coordinates are world coordinates for the single entities, chunk coordinates for the chunks, times are measured in milliseconds.

Will hopefully have time tomorrow or later tonight to release a coremod which improves FPS by doing two things: allowing you to set the maximum TileEntity rendering range, and making quartz crystals render as solid blocks.

edit: As /u/duaiwe has kindly updated it, the latest build is now for minecraft 1.5.2. The newest build for 1.4.7 is available here.