try to search here for "smt":
http://www-03.ibm.com/support/techdo...f/Web/Techdocs

There is no special document for POWER5+. But I don't think there is a
difference to POWER5 with SMT.

Cheers,

Andy


On Wed, 04 Apr 2007 20:05:11 -0500, "Michael E. Thomadakis"
<miket@sc.tamu.edu> wrote:

>Jan-Frode Myklebust wrote:
>> On 2007-04-04, Michael E. Thomadakis <miket@sc.tamu.edu> wrote:
>>> More specifically, I would expect that SMT ON would benefit workload
>>> mixes with high thread concurrency but with low contention on common
>>> thread resources (L1/L2/L3 and functional units). For instance, I would
>>> expect a cluster with a large number of distributed (and multithreaded)
>>> processes running to benefit from SMT ON: twice as many h/w threads can
>>> be active at a time, obviating the need for costly thread-switch.
>>
>> I did some benchmarking on a P5+ cluster last fall, and was
>> quite surprised that SMT=ON (and 1 task per virtuall cpu vs.
>> 1 task per physical cpu in SMT=OFF) was giving best performance
>> on all the benchmarks we did. Even for 16 node (~250 task)
>> mpi-jobs.
>>
>>
>> -jf
>
>Jan thanks for your reply. We have a 40 node p5-575 cluster with 32GB
>DRAM/node. Nodes are attached to 2 planes of HPS. I was contending that
>SMT ON should benefit the cluster since all of the cluster control
>processes (RSCT, GPFS, HPS assistance, etc.) are heavily multi-threaded
>and by not being compute-intensive, they should benefit from SMT ON.
>
>Are there any public benchmarks that I can run to demonstrate the
>benefits of SMT ?
>
>thanks again,
>Michael


--
Andreas Beckmann
Andreas.Beckmann@muenster.de
http://www.muenster.de/~andy