[Haskell-cafe] Performance difference between Linux and Windows?

[Krzysztof Skrzętnicki]

The difference is roughly 2x, which suggests difference in Int/pointer
sizes: 32bit vs 64bit. Indeed, only since 7.6.1. GHC supports compiling 64
bit executables on Windows (
http://hackage.haskell.org/trac/ghc/wiki/WindowsGhc). That means that in
fact you compare 32 bit vs 64 bit programs.

I didn't have a look at the code so this is just a wild guess.

Best regards,
Krzysztof Skrzętnicki

On Fri, May 31, 2013 at 3:26 PM, James Jones <jejones3141 at gmail.com> wrote:

> I've been having a great deal of fun writing a program to solve this
> year's Code Jam "Fair and Square"problem in Haskell (and learning about
> Haskell in the process). Having gotten it to work, I've been optimizing it
> as best I can. I'm not quite in Captain Ahab mode, but before I let it go I
> would like to find out what's behind a difference I've seen compiling and
> running the program under Linux and under Windows 7.
>
> Profiling it under Linux (compiled with GHC 7.4.1), it had a total
> allocation of 165,375,112 bytes. I had an opportunity to compile and run on
> Windows 7, with GHC 7.4.2. I expected it to run faster, since the Windows
> computer had a 3.1 GHz i7 and my Linux computer has a 2.8 GHz AMD Propus,
> but what I didn't expect was that the total allocation on the Windows
> version was 88,438,372 bytes!
>
> Thinking it might be due to a compiler improvement, I upgraded my Linux
> computer to Ubuntu 13.04 so I could get a newer GHC, but it didn't make
> much difference: total allocation 163,248,688 bytes.
>
> So, I'm wondering: what is it about either the Windows implementation or
> GHC 7.4.2 in particular that would make a factor of two difference in
> memory allocation? Should anyone wish to compile the program, let me know
> the best way to make the source available and I will happily do so; I also
> use Twan van Laarhoven's semilattice search tree code available at
> http://twanvl.nl/blog/haskell/SemilatticeSearchTree.
>
> James Jones
>
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