[Haskell-cafe] Optimizing a hash function

Ivan Tomac tomac at pacific.net.au
Mon Nov 27 04:27:11 EST 2006


I've seen that guide before and followed the suggestions in there but  
somehow I missed the -funfolding-use-threshhold option. After setting  
it to 24 the code now runs about 2-3 times slower than C which is a  
significant improvement from a factor of 10.
Thanks :)


On 27/11/2006, at 12:04 AM, isto wrote:

> Have you tried -O3 -optc-O3  -funfolding-use-threshold=16
> compile flags?  Don, Lemmih, Lennart and Bulat helped me to sort
> out a similar problem a couple of weeks ago. More hints can be  
> found at
> http://haskell.org/haskellwiki/Performance/GHC
> Especially, to check generated code by taking a look of core
> -ddump-simpl > core.txt
> and to check memory leaks, you could run with
> +RTS -sstderr
> br, Isto

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