[Haskell] repa not running in parallel?

[Claude Heiland-Allen]

Hi Alexander,

On 07/11/13 09:40, Alexander Herz wrote:
> Hi,
>
> I'm new to haskell and I tried to reproduce the perfomance values from
> the paper "Regular, Shape-polymorphic, Parallel Arrays in Haskell".
>
> I modified the repa-mmult example from the repa-example package to use
> the mmultP from Data.Array.Repa.Algorithms.Matrix.
>
> Then I compile it with "ghc -threaded -fglasgow-exts -O Main.hs" but
> running it with two large matrices :
>
> "./Main -random 4096 4096 -random 4096 4096" I can see that only one of
> my 4 cpus is utilized.
>
> What am I doing wrong?

Probably, not running with ./Main +RTS -N -RTS ...

http://www.haskell.org/ghc/docs/7.6.3/html/users_guide/using-smp.html#parallel-options

> Note: The unmodified repa-example also does not run in parallel.
>
> Thx,
> Alex


Claude
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