Maybe it's time to update the saying that 'numbers never lie' to
something more accurate - 'numbers never lie, but they also rarely
tell the whole story'.
May I offer you a different saying in these trying times?
https://en.wikipedia.org/wiki/Lies,_damned_lies,_and_statistics
Prentice Bisbal
Senior HPC Engineer
Computational Sciences Department
Princeton Plasma Physics Laboratory
https://cs.pppl.gov
https://www.pppl.gov
On 3/18/22 8:20 PM, Brian Dobbins wrote:
Hi Jorg,
We (NCAR - weather/climate applications) tend to find that HPCG more
closely tracks the performance we see from hardware than Linpack, so
it definitely is of interest and watched, but our procurements tend to
use actual code that vendors run as part of the process, so we don't
'just' use published HPCG numbers. Still, I'd say it's still very
much a useful number, though.
As one example, while I haven't seen HPCG numbers for the MI250x
accelerators, Prof. Matuoka of RIKEN tweeted back in November that he
anticipated that to score around 0.4% of peak on HPCG, vs 2% on the
NVIDIA A100 (while the A64FX they use hits an impressive 3%):
https://twitter.com/ProfMatsuoka/status/1458159517590384640
Why is that relevant? Well, /on paper/, the MI250X has ~96 TF FP64
w/ Matrix operations, vs 19.5 TF on the A100. So, 5x in theory, but
Prof Matsuoka anticipated a ~5x differential in HPCG, /erasing/ that
differential. Now, surely /someone/ has HPCG numbers on the MI250X,
but I've not yet seen any. Would love to know what they are. But
absent that information I tend to bet Matsuoka isn't far off the mark.
Ultimately, it may help knowing more about what kind of applications
you run - for memory bound CFD-like codes, HPCG tends to be pretty
representative.
Maybe it's time to update the saying that 'numbers never lie' to
something more accurate - 'numbers never lie, but they also rarely
tell the whole story'.
Cheers,
- Brian
On Fri, Mar 18, 2022 at 5:08 PM Jörg Saßmannshausen
<sassy-w...@sassy.formativ.net> wrote:
Dear all,
further the emails back in 2020 around the HPCG benchmark test, as
we are in
the process of getting a new cluster I was wondering if somebody
else in the
meantime has used that test to benchmark the particular
performance of the
cluster.
From what I can see, the latest HPCG version is 3.1 from August
2019. I also
have noticed that their website has a link to download a version
which
includes the latest A100 GPUs from nVidia.
https://www.hpcg-benchmark.org/software/view.html?id=280
What I was wondering is: has anybody else apart from Prentice
tried that test
and is it somehow useful, or does it just give you another set of
numbers?
Our new cluster will not be at the same league as the
supercomputers, but we
would like to have at least some kind of handle so we can compare
the various
offers from vendors. My hunch is the benchmark will somehow
(strongly?) depend
on how it is tuned. As my former colleague used to say: I am
looking for some
war stories (not very apt to say these days!).
Either way, I hope you are all well given the strange new world we
are living
in right now.
All the best from a spring like dark London
Jörg
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