Re: Short Vectors Versus Long Vectors

On Thu, 25 Apr 2024 05:39:55 -0000 (UTC)
Lawrence D'Oliveiro <ldo@nz.invalid> wrote:

On Wed, 24 Apr 2024 23:10:47 -0600, John Savard wrote:
 

One of the things that those supercomputers that _do_ include GPUs
are praised for is being energy-efficient. 

 
That I never heard before. I heard it in relation to ARM CPUs, yes,
GPUs, no.

If you never heard about *that*, I can only imagine what else you
didn't hear about supercomputers.

Back when Fugaku was new, it was highly praised for being GPU-less
design that matches and slightly exceeds an efficiency of
GPU-based (and other vector accelerator based) supercomputers. But that
was possible only because NVidea had unusually long pause between
successive generations of Tesla and at the same moment AMD and
Intel GPGPUs were not yet considered fit for serious supercomputing.

That was in November 2019. Never before or since.
Right now the best GPU-less entry on Green500 list is #48 (still the
same A64FX CPU as Fugaku, but smaller configuration) and it delivers 4x
less sustained FLOP/Watt than the top spot, based on NVIDIA H100.