Kilian/All, Thanks for the responses. Regarding "peak" ... if I did not include it, I should have said "nominal" peak, which is about the only meaning peak has these days.
Seeing as I have not had a lot of quick "this is how you get 90% efficiency" answers, but references and comments that corroborate the performance I am observing, I will conclude for the moment that the 80% figure for these 64-core parts is a good-reasonable number. Also, it is a reminder that even HPL has an on-node bandwidth performance dependency, although I guess we cannot be sure here what part of the 20% difference when compared to the 32-core parts is strictly due to bandwidth to memory and not to increased competition for the on-chip caches when we double the number of cores. Thanks, Richard On Tue, Aug 18, 2020 at 6:22 PM Kilian Cavalotti < kilian.cavalotti.w...@gmail.com> wrote: > Hi Richard, > > On Fri, Aug 14, 2020 at 2:30 PM Richard Walsh <rbwcn...@gmail.com> wrote: > > What have people achieved on this SKU on a single-node using the stock > > HPL 2.3 source... ?? > > I got similar findings as yours, about 75-80% of peak, albeit using a > different SKU (7702), but consistent over multiple platforms (thus > hopefully averaging manufacturer idiosyncrasies). > > I think this page summarizes the most relevant BIOS settings pretty > well: > https://hpcadvisorycouncil.atlassian.net/wiki/spaces/HPCWORKS/pages/1280442391/AMD+2nd+Gen+EPYC+CPU+Tuning+Guide+for+InfiniBand+HPC#Configurable-Thermal-Design-Power-(cTDP) > > > I have seen a variety of performance claims even as high as 90% of its > nominal per node peak of 4.608 TFLOPs. > > Interestingly, the theoretical performance of a dual-7742 machine is > 4.608 TFLOPs, at *base* clock (2.25 GHz). > In practice, you probably had Turbo on, meaning that the clocks were > probably running closer to the 3.0 GHz range, which means that the > theoretical performance should be in the 6 TF range, hence bringing > the observed efficiency even lower. > > An interesting test would be to disable Turbo to fix the core clocks > at 2.25 GHz, and see the HPL numbers you get. > > Cheers, > -- > Kilian >
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