[Beowulf] gpgpu

Geoff Jacobs gdjacobs at gmail.com
Mon Aug 25 19:21:21 PDT 2008


Vincent Diepeveen wrote:
> Hi Mikhail,
> 
> I'd say they're ok for black box 32 bits calculations that can do with a
> GB or 2 RAM,
> other than that they're just luxurious electric heating.

Rather tangential, if I do say so...

All the latest GPUs (GT200 and R7xx) do DP now.

To answer the original question, AMD very definitely does SIMD. Shaders
are grouped in fives, each group being dispatched a single VLIW
instruction which operates on all five. NVidia unified shaders are
scalar, however.

> 
> Vincent
> 
> p.s. if you ask me, honestely, 250 watt or so for latest gpu is really
> too much.
> IMHO cpu's as well as gpu's should budget themselves more to a few tens
> of watts at most.
> Say 50 watt for the high end models.
> 
> On Aug 23, 2008, at 10:31 PM, Mikhail Kuzminsky wrote:
> 
>> BTW, why GPGPUs are considered as vector systems ?
>> Taking into account that GPGPUs contain many (equal) execution units,
>> I think it might be not SIMD, but SPMD model. Or it depends from the
>> software tools used (CUDA etc) ?
>>
>> Mikhail Kuzminsky
>> Computer Assistance to Chemical Research Center
>> Zelinsky Institute of Organic Chemistry
>> Moscow
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-- 
Geoffrey D. Jacobs



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