[Haskell-cafe] Problems with threading?

[Don Stewart]

wasserman.louis:
> 
>     There are 4 sets of "rankings" so -
> 
>     http://shootout.alioth.debian.org/u64/program.php?test=threadring&lang=ghc&
>     id=3
> 
> 
> Yes, but Haskell used to be doing much better specifically on the u64q, which
> was why I was surprised.

Oh, indeed,

    http://shootout.alioth.debian.org/u64q/performance.php?test=threadring

Something broke.

Simon Marlow described how best to parallelize this problem extensively
in:

    http://www.haskell.org/~simonmar/bib/multicore-ghc-09_abstract.html

So I'd suggest doing what he says.

In particular, use thread pinning to improve locality.

-- Don