[Haskell-cafe] C-like Haskell

sam lee skynare at gmail.com
Wed Jan 28 20:11:28 EST 2009


Did you print it? I'm using same code with ghc --make -O2  and it
takes forever to finish.


On Wed, Jan 28, 2009 at 8:06 PM, Duncan Coutts
<duncan.coutts at worc.ox.ac.uk> wrote:
> On Wed, 2009-01-28 at 16:42 -0800, drblanco wrote:
>
>> I do already have the number I wanted, but was wondering how this could be
>> made faster, or even why it's so slow.  This is all on GHC 6.8.3 under OS X
>> Intel, using ghc -O2.
>
> I'm not exactly sure what's different, but for me it works pretty well.
> I put back in the Int64 type signature.
>
>> For comparison, the C code below runs in <1 second.
>
> You've got a faster machine than me :-)
>
> I compiled both the Haskell and C versions to standalone executables
> with ghc/gcc -O2 and ran them with time.
>
> C version:
> $ time ./circ
> 3141592649589764829
>
> real    0m2.430s
> user    0m2.428s
> sys     0m0.000s
>
> Haskell version:
> time ./circ2
> 3141592653589764829
>
> real    0m2.753s
> user    0m2.756s
> sys     0m0.000s
>
>
> Not too bad I'd say! :-)
>
> I was using ghc-6.10 for this test. It would appear that ghc-6.8 is a
> bit slower, I get:
>
> 3141592653589764829
>
> real    0m5.767s
> user    0m5.768s
> sys     0m0.000s
>
> Now the other difference is that I'm using a 64bit machine so perhaps
> ghc just produces terrible code for Int64 on 32bit machines.
>
> Duncan
>
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