On Friday, 23 February 2018 1:45:00 AM AEDT Joe Landman wrote: > 85% makes the assumption that you have the systems configured in an > optimal manner, that the compiler doesn't do anything wonky, and that, > to some degree, you isolate the OS portion of the workload off of most > of the cores to reduce jitter. Among other things.
Interesting, purchases I've done before for IB clusters have had Rpeak as 80% of Rmax HPL requirement for acceptance testing before and not had much problem hitting it. The worst issue we had was on SandyBridge where the kernel ignoring UEFI settings saying "hey, I know these CPUs, I'll enable ALL the power saving" and that killed performance until we disabled the states via the kernel boot parameters. It can be worth running powertop to see what states your CPUs are sitting in whilst running HPL, and also "perf top" to see what the system is up to. Good luck! Chris -- Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
