[Haskell-cafe] Re: C-like Haskell

[Benedikt Huber]

Ross Mellgren schrieb:
> Duncan, I think you must have some magics -- on my machine the original 
> code also takes forever.
> Running with +RTS -S indicates it's allocating several gig of memory or 
> more.
> 
> Applying some bang patterns gives me ~8s for 10^8 and somewhat more than 
> a minute for 10^9:
Hi,
same here, with bang patterns ~100s / 1Mb but

> The C program is quite fast:
> 
> rmm at Hugo:~$ time ./circ-orig
> 1302219321
looks wrong to me
> 
> real    0m1.073s

cafe(0) $ time ./gauss
3141592649589764829
real	0m17.894s

So my 32-bit machine is really slow ...

benedikt


> 
>> 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
>>
>> _______________________________________________
>> Haskell-Cafe mailing list
>> Haskell-Cafe at haskell.org
>> http://www.haskell.org/mailman/listinfo/haskell-cafe