Benchmarks: Excellent Power Efficiency With 5th Gen AMD EPYC Using amd-pstate & Power Profiles
In a number of the workloads tested on this dual socket EPYC 9755 server, the raw performance was minimally changed when applying some of the power efficiency optimizations...
But sure enough when applying the "Balanced Memory" Power Profile mode from the BIOS, there was a clear difference in the CPU power consumption. The combined CPU power consumption of the dual EPYC 9755 128-core processors dropped from a peak of 560~577 Watts down to 535 Watts. The average EPYC 9755 2P power consumption in the recommended balanced memory mode was at 95% the power use of the default mode.
Thus a nice boost to the performance-per-Watt in the ACES DGEMM benchmark for example when running in the balanced memory mode for some power savings without costing much in terms of performance.
With the Incompact3D HPC benchmark where the CPUs were running fully utilized, there wasn't any major difference to the performance but the Balanced Memory mode led the combined EPYC 9755 2P power consumption to run at 797~815 Watts compared to an average of 828 Watts at the defaults. So again some energy efficiency advantages without being really detrimental to the EPYC server performance.
Moving to some of the OpenJDK/Java workloads is where they are much more susceptible to driver/governor/power-profile changes. With the Avrora simulation framework some nice performance while using the AMD P-State driver and better than the former default with ACPI CPUFreq. Even with the balanced memory mode of operation was a good showing for raw performance.
When looking at the combined EPYC 9755 CPU power consumption though is where the Balanced Memory mode impact was very evident.
Running with the amd-pstate powersave configuration with EPP performance setting and Balanced Memory mode led to 1.19x the energy efficiency at the defaults or 1.44x compared to the ACPI CPUFreq performance default formerly used on older kernels/distributions.