On 7/17/06, Bulat Ziganshin wrote:

Hello Asfand,

Monday, July 17, 2006, 7:31:23 PM, you wrote:

...

I finally got my spiffy dual-core processor (an Opteron 165 no-less) and want to learn STM, since I think it and haskell are the future of concurrent programming.

...

How do I compile Haskell to be able learn STM on it, using "proper" threading? I know there's a parallel haskell flag, but I read somewhere about it running on top of some special server that lets it work in parallel threads or something.

you should compile with "-threaded" flag which allows to preempt threads created in your program with forkIO/forkOS

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 :-)

Duncan Coutts wrote:

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

Yes, although -smp is now the same as -threaded, so for simplicity we'll stop referring to -smp and just use -threaded (it'll still be accepted for backwards compatibility, though). Cheers, Simon