On 3/27/07, Jeremy Shaw
At Tue, 27 Mar 2007 23:10:21 +0200, Fawzi Mohamed wrote:
If someone has an idea on how else I can improve timings please tell me.
I believe you are seeing a speed decrease, because GHC is not inlining functions as much when you split them into modules. If you add explicit inline statements, I think you should be able to get back to your original timings.
It could be inlining or it could be other optimizations. From the data the OP gives, I don't think it's possible to conclude which ones.
Below is an example of how to add INLINE statements.
someFunction :: (Word8 -> Maybe Word8 -> Bool) -> B.ByteString -> B.ByteString someFunction = ... {-# INLINE someFunction #-}
I am not sure what the downsides are. It probably makes the resulting binary bigger, and takes longer to compile. Though, probably not any worse than if you just put everything in one module?
That's not necessarily so; what if you end up adding an INLINE pragma for a function with several call sites that GHC wouldn't have inlined at all in the original single-module program?
It might be the case that you only need to INLINE one or two functions to get most of the speed back.
Yes, which is why it's a good idea to do profiling before sprinkling INLINE pragmas wantonly around your code. Cheers, Tim -- Tim Chevalier * chevalier@alum.wellesley.edu * Often in error, never in doubt Confused? See http://catamorphism.org/transition.html