Intel Xeon Platinum 8380 P-State CPU Frequency Scaling Comparison

Written by Michael Larabel in Software on 7 June 2021. Page 2 of 6. 6 Comments

For those that haven't looked at the Intel P-State governor choices recently or our other benchmarks on recent kernels, for some workloads, it doesn't make much difference:

But then for some workloads, running with the more aggressive performance governor can make some significant impact especially for shorter-running workloads:

As we have seen with recent kernels and recent generations of Intel desktops/servers, in some cases using the performance governor is very beneficial to the overall performance and especially for servers somewhat unfortunate more Linux distributions don't default to using it.

This comes with the performance governors keeping the CPU cores near their highest performance state nearly the entire time under load compared to the Schedutil or Powersave governors being more conservative in ramping up their frequencies.

In the case of this NPB benchmark, this meant the performance governor with the dual Xeon Platinum 8380 processors having a combined ~130 Watt higher power consumption over the powersave governor.

So on a performance-per-Watt basis, P-State powersave came out in front while the schedutil governor was slightly better than the performance mode.

With HPCG there was some very slight differences in performance across the frequency scaling governors tested.

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