[Haskell-cafe] Compiling ghc for using STM

Duncan Coutts duncan.coutts at worc.ox.ac.uk
Mon Jul 17 13:46:30 EDT 2006

On Mon, 2006-07-17 at 18:29 +0100, Asfand Yar Qazi wrote:
> On 7/17/06, Bulat Ziganshin <bulat.ziganshin at gmail.com> wrote:
> >
> > if you want to really use 2 processors, you should use ghc 6.5, which
> > is still in beta stage. ghc 6.4 executes all the Haskell code on one
> > processor (to be exact, at each moment there is only one program
> > thread executing Haskell code)
> I should have explained: I've already got ghc trunk successfully
> compiled.  I just need to turn on native threading or whatever its
> called so I can learn STM'ism (and no, I can't make do with in-process
> threads - I didn't pay 230 GBP for a dual-core processor to have one
> in the background processing cron jobs :-)
> So, as soon as I figure out how to compile ghc 6.5 beta, and how to
> include parallelisation support, I'm set :-)

I believe that the smp flavour of the RTS is now built by default and so
all you need to do is use it when linking a program:

ghc-6.5 -smp Foo.hs -o foo

Then when running the program you can tell the RTS how many OS threads
to use:

./foo +RTS -N2 -RTS


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