[Haskell-cafe] ANNOUNCE: Sun Microsystems and Haskell.org joint project on OpenSPARC

Ben Lippmeier Ben.Lippmeier at anu.edu.au
Thu Jul 24 20:54:13 EDT 2008

The UltraSPARC T1/T2 architecture supports very fast thread
synchronisation (by taking advantage of the fact that all threads
share the same L2 cache).

Ah, scratch that second part then - though this is perhaps less of an  
issue when you have 4MB of L2 cache, vs the 256k cache for the machine  
in the paper.


On 25/07/2008, at 10:38 AM, Ben Lippmeier wrote:

> On 25/07/2008, at 8:55 AM, Duncan Coutts wrote:
>> Right. GHC on SPARC has also always disabled the register window when
>> running Haskell code (at least for registerised builds) and only  
>> uses it
>> when using the C stack and calling C functions.
> I'm not sure whether register windows and continuation based back- 
> ends are ever going to be very good matches - I don't remember the  
> last time I saw a 'ret' instruction in the generated code :). If  
> there's a killer application for register windows in GHC it'd be  
> something tricky.
> I'd be more interested in the 8 x hardware threads per core, [1]  
> suggests that (single threaded) GHC code spends over half its time  
> stalled due to L2 data cache miss. 64 threads per machine is a good  
> incentive for trying out a few `par` calls..
> Ben.
> [1] http://www.cl.cam.ac.uk/~am21/papers/msp02.ps.gz

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