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<p>Thanks for the resources. I will definitely read/watch them when
I can block out some time. I see he uses LAMMPS as one of his
benchmarks. I was considering adding LAMMPS to my testing regimen,
since it's a code I have familiarity with, and my own background
is in chemistry. <br>
</p>
<pre class="moz-signature" cols="72">Prentice </pre>
<div class="moz-cite-prefix">On 6/20/21 1:38 AM, John Hearns wrote:<br>
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cite="mid:CAPqNE2WnHFB8aqf1LgHT0FUm+R3Y8+BiujCCndmC4f5ywQRA5w@mail.gmail.com">
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<div dir="ltr">Regarding benchmarking real world codes on AMD ,
every year Martyn Guest presents a comprehensive set of
benchmark studies to the UK Computing Insights Conference.
<div>I suggest a Sunday afternoon with the beverage of your
choice is a good time to settle down and take time to read
these or watch the presentation.</div>
<div><br>
</div>
<div>2019</div>
<div><a
href="https://www.scd.stfc.ac.uk/SiteAssets/Pages/CIUK-2019-Presentations/Martyn_Guest.pdf"
moz-do-not-send="true">https://www.scd.stfc.ac.uk/SiteAssets/Pages/CIUK-2019-Presentations/Martyn_Guest.pdf</a><br>
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<div>2020 Video session</div>
<div><a
href="https://ukri.zoom.us/rec/share/ajvsxdJ8RM1wzpJtnlcypw4OyrZ9J27nqsfAG7eW49Ehq_Z5igat_7gj21Ge8gWu.78Cd9I1DNIjVViPV?startTime=1607008552000"
moz-do-not-send="true">https://ukri.zoom.us/rec/share/ajvsxdJ8RM1wzpJtnlcypw4OyrZ9J27nqsfAG7eW49Ehq_Z5igat_7gj21Ge8gWu.78Cd9I1DNIjVViPV?startTime=1607008552000</a></div>
<div><br>
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<div>Skylake / Cascade Lake / AMD Rome</div>
<div><br>
</div>
<div>The slides for 2020 do exist - as I remember all the slides
from all talks are grouped together, but I cannot find them.</div>
<div>Watch the video - it is an excellent presentation.</div>
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<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sat, 19 Jun 2021 at 16:49,
Gerald Henriksen <<a href="mailto:ghenriks@gmail.com"
moz-do-not-send="true">ghenriks@gmail.com</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">On
Wed, 16 Jun 2021 13:15:40 -0400, you wrote:<br>
<br>
>The answer given, and I'm <br>
>not making this up, is that AMD listens to their users and
gives the <br>
>users what they want, and right now they're not hearing
any demand for <br>
>AVX512.<br>
><br>
>Personally, I call BS on that one. I can't imagine anyone
in the HPC <br>
>community saying "we'd like processors that offer only 1/2
the floating <br>
>point performance of Intel processors".<br>
<br>
I suspect that is marketing speak, which roughly translates to
not<br>
that no one has asked for it, but rather requests haven't
reached a<br>
threshold where the requests are viewed as significant enough.<br>
<br>
> Sure, AMD can offer more cores, <br>
>but with only AVX2, you'd need twice as many cores as
Intel processors, <br>
>all other things being equal.<br>
<br>
But of course all other things aren't equal.<br>
<br>
AVX512 is a mess.<br>
<br>
Look at the Wikipedia page(*) and note that AVX512 means
different<br>
things depending on the processor implementing it.<br>
<br>
So what does the poor software developer target?<br>
<br>
Or that it can for heat reasons cause CPU frequency
reductions,<br>
meaning real world performance may not match theoritical -
thus easier<br>
to just go with GPU's.<br>
<br>
The result is that most of the world is quite happily (at
least for<br>
now) ignoring AVX512 and going with GPU's as necessary -
particularly<br>
given the convenient libraries that Nvidia offers.<br>
<br>
> I compared a server with dual AMD EPYC >7H12
processors (128)<br>
> quad Intel Xeon 8268 >processors (96 cores).<br>
<br>
> From what I've heard, the AMD processors run much hotter
than the Intel <br>
>processors, too, so I imagine a FLOPS/Watt comparison
would be even less <br>
>favorable to AMD.<br>
<br>
Spec sheets would indicate AMD runs hotter, but then again you<br>
benchmarked twice as many Intel processors.<br>
<br>
So, per spec sheets for you processors above:<br>
<br>
AMD - 280W - 2 processors means system 560W<br>
Intel - 205W - 4 processors means system 820W<br>
<br>
(and then you also need to factor in purchase price).<br>
<br>
>An argument can be made that for calculations that lend
themselves to <br>
>vectorization should be done on GPUs, instead of the main
processors but <br>
>the last time I checked, GPU jobs are still memory is
limited, and <br>
>moving data in and out of GPU memory can still take time,
so I can see <br>
>situations where for large amounts of data using CPUs
would be preferred <br>
>over GPUs.<br>
<br>
AMD's latest chips support PCI 4 while Intel is still stuck on
PCI 3,<br>
which may or may not mean a difference.<br>
<br>
But what despite all of the above and the other replies, it is
AMD who<br>
has been winning the HPC contracts of late, not Intel.<br>
<br>
* - <a
href="https://en.wikipedia.org/wiki/Advanced_Vector_Extensions"
rel="noreferrer" target="_blank" moz-do-not-send="true">https://en.wikipedia.org/wiki/Advanced_Vector_Extensions</a><br>
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</blockquote>
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