Parallel GHC on Altix?

Simon Marlow simonmarhaskell at
Mon May 8 07:19:57 EDT 2006

Chad Scherrer wrote:

> I'd like to get more involved in parallel programming in Haskell, and I 
> have access to an SGI Altix machine (a shared-memory multiprocessor). 
> Can someone tell me, if I download a 64-bit GHC 6.5 snapshot, to what 
> extent will parallelism "just work"? Specifically, I'm interested in
> * parallel evaluation strategies
> * nested data parallelism
> * forkIO, MVar's, and STM
> My understanding is that for the 32-bit version, this all works in 
> parallel, but GC is sequential. Is that still the case? Is the 64-bit 
> version in the same state?

nested data parallelism: not yet.  forkIO, MVars, STM, par, and 
strategies are all working in 6.5 right now.  throwTo is not working on 
multiple CPUs yet.

There shouldn't be any difference between 32 and 64 bit support.

> Finally, is there an estimated date for when 6.6 will be available? I'm 
> happy to experiment with snapshots, but most admins around here are much 
> more comfortable installing an official release of some sort.

We don't have a firm schedule, as usual it's "when it's done".  To get 
an idea of what is still to be done, these tickets are scheduled for 6.6:

as a rough guide, I'd like to get 6.6 out sometime this summer, and 
definitely before ICFP/Haskell Workshop/GHC Hackathon.


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