how to break up a large module?

I recently spent a couple of hours breaking up a large module (2.5k lines) into several smaller modules. When I finally got it working, I found that my program took about 60% longer to run. This was running ghc with -O optimization. Any suggestions how to go about breaking up a module in such a way that it doesn't slow things down? Do I just have to go adding INLINE directives to all my functions? Or is there some other trick I could use? For the moment I've reverted to my single big file method, but it certainly would be handy to be able to break that up so that it wouldn't take so long to recompile. -- David Roundy http://www.abridgegame.org