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<div> 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'.</div>
<div><br>
</div>
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May I offer you a different saying in these trying times? <br>
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<p><a class="moz-txt-link-freetext" href="https://en.wikipedia.org/wiki/Lies,_damned_lies,_and_statistics">https://en.wikipedia.org/wiki/Lies,_damned_lies,_and_statistics</a><br>
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<pre class="moz-signature" cols="72">Prentice Bisbal
Senior HPC Engineer
Computational Sciences Department
Princeton Plasma Physics Laboratory
<a class="moz-txt-link-freetext" href="https://cs.pppl.gov">https://cs.pppl.gov</a>
<a class="moz-txt-link-freetext" href="https://www.pppl.gov">https://www.pppl.gov</a></pre>
<div class="moz-cite-prefix">On 3/18/22 8:20 PM, Brian Dobbins
wrote:<br>
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<blockquote type="cite"
cite="mid:CAFkGP2=mbxrFoxseKA67SLX7mDfhToqBAstVi9nJuHrd3aVXzw@mail.gmail.com">
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<div>Hi Jorg,<br>
</div>
<div><br>
</div>
<div> 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.</div>
<div><br>
</div>
<div> 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%):</div>
<div><a
href="https://twitter.com/ProfMatsuoka/status/1458159517590384640"
moz-do-not-send="true" class="moz-txt-link-freetext">https://twitter.com/ProfMatsuoka/status/1458159517590384640</a></div>
<div><br>
</div>
<div> Why is that relevant? Well, <i>on paper</i>, 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, <i>erasing</i> that differential. Now,
surely <i>someone</i> 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.</div>
<div><br>
</div>
<div> 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. <br>
</div>
<div><br>
</div>
<div> 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'.</div>
<div><br>
</div>
<div> Cheers,</div>
<div> - Brian</div>
<div><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri, Mar 18, 2022 at 5:08
PM Jörg Saßmannshausen <<a
href="mailto:sassy-work@sassy.formativ.net"
moz-do-not-send="true" class="moz-txt-link-freetext">sassy-work@sassy.formativ.net</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Dear
all,<br>
<br>
further the emails back in 2020 around the HPCG benchmark
test, as we are in <br>
the process of getting a new cluster I was wondering if
somebody else in the <br>
meantime has used that test to benchmark the particular
performance of the <br>
cluster. <br>
From what I can see, the latest HPCG version is 3.1 from
August 2019. I also <br>
have noticed that their website has a link to download a
version which <br>
includes the latest A100 GPUs from nVidia. <br>
<a
href="https://www.hpcg-benchmark.org/software/view.html?id=280"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://www.hpcg-benchmark.org/software/view.html?id=280</a><br>
<br>
What I was wondering is: has anybody else apart from Prentice
tried that test <br>
and is it somehow useful, or does it just give you another set
of numbers?<br>
<br>
Our new cluster will not be at the same league as the
supercomputers, but we <br>
would like to have at least some kind of handle so we can
compare the various <br>
offers from vendors. My hunch is the benchmark will somehow
(strongly?) depend <br>
on how it is tuned. As my former colleague used to say: I am
looking for some <br>
war stories (not very apt to say these days!).<br>
<br>
Either way, I hope you are all well given the strange new
world we are living <br>
in right now.<br>
<br>
All the best from a spring like dark London<br>
<br>
Jörg<br>
<br>
<br>
<br>
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