Regarding benchmarking real world codes on AMD , every year Martyn Guest presents a comprehensive set of benchmark studies to the UK Computing Insights Conference. 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.
2019 https://www.scd.stfc.ac.uk/SiteAssets/Pages/CIUK-2019-Presentations/Martyn_Guest.pdf 2020 Video session https://ukri.zoom.us/rec/share/ajvsxdJ8RM1wzpJtnlcypw4OyrZ9J27nqsfAG7eW49Ehq_Z5igat_7gj21Ge8gWu.78Cd9I1DNIjVViPV?startTime=1607008552000 Skylake / Cascade Lake / AMD Rome The slides for 2020 do exist - as I remember all the slides from all talks are grouped together, but I cannot find them. Watch the video - it is an excellent presentation. On Sat, 19 Jun 2021 at 16:49, Gerald Henriksen <ghenr...@gmail.com> wrote: > On Wed, 16 Jun 2021 13:15:40 -0400, you wrote: > > >The answer given, and I'm > >not making this up, is that AMD listens to their users and gives the > >users what they want, and right now they're not hearing any demand for > >AVX512. > > > >Personally, I call BS on that one. I can't imagine anyone in the HPC > >community saying "we'd like processors that offer only 1/2 the floating > >point performance of Intel processors". > > I suspect that is marketing speak, which roughly translates to not > that no one has asked for it, but rather requests haven't reached a > threshold where the requests are viewed as significant enough. > > > Sure, AMD can offer more cores, > >but with only AVX2, you'd need twice as many cores as Intel processors, > >all other things being equal. > > But of course all other things aren't equal. > > AVX512 is a mess. > > Look at the Wikipedia page(*) and note that AVX512 means different > things depending on the processor implementing it. > > So what does the poor software developer target? > > Or that it can for heat reasons cause CPU frequency reductions, > meaning real world performance may not match theoritical - thus easier > to just go with GPU's. > > The result is that most of the world is quite happily (at least for > now) ignoring AVX512 and going with GPU's as necessary - particularly > given the convenient libraries that Nvidia offers. > > > I compared a server with dual AMD EPYC >7H12 processors (128) > > quad Intel Xeon 8268 >processors (96 cores). > > > From what I've heard, the AMD processors run much hotter than the Intel > >processors, too, so I imagine a FLOPS/Watt comparison would be even less > >favorable to AMD. > > Spec sheets would indicate AMD runs hotter, but then again you > benchmarked twice as many Intel processors. > > So, per spec sheets for you processors above: > > AMD - 280W - 2 processors means system 560W > Intel - 205W - 4 processors means system 820W > > (and then you also need to factor in purchase price). > > >An argument can be made that for calculations that lend themselves to > >vectorization should be done on GPUs, instead of the main processors but > >the last time I checked, GPU jobs are still memory is limited, and > >moving data in and out of GPU memory can still take time, so I can see > >situations where for large amounts of data using CPUs would be preferred > >over GPUs. > > AMD's latest chips support PCI 4 while Intel is still stuck on PCI 3, > which may or may not mean a difference. > > But what despite all of the above and the other replies, it is AMD who > has been winning the HPC contracts of late, not Intel. > > * - https://en.wikipedia.org/wiki/Advanced_Vector_Extensions > _______________________________________________ > Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing > To change your subscription (digest mode or unsubscribe) visit > https://beowulf.org/cgi-bin/mailman/listinfo/beowulf >
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