On Mon, 30 Jul 2001, Simon Marlow wrote:
I've looked at a few. The most common factor in the worst performers seems to be the performance of String-related operations. I tried converting a few to use PackedStrings but that didn't help much. I suspect our PackedString implementation could do with some tuning, and we could gain considerable benefit from having an hGetLinePS function (like hGetLine but gets a PackedString).
Well, I think the common factor is I/O. The lazy I/O seems to be a real bottleneck here. Trying to improve that would gain even more, I think. I'm saying this because I did quite a bit of fiddling with some of the examples (including trying PackedStrings). The conclusion I drew from doing this was that the I/O performance was the problem. Having said that I must also say that I think that ghc's I/O is fast *enough*. It's just that it doesn't compare very well with other languages. I've never had problems caused by slow I/O in Haskell. Anyway, don't let this stop you from tuning and expanding that PackedString library. I would love to see a PackedString library for ghc which is as complete as hbc's ;-) Cheers, /Josef