Ryzen Mobile Power/Performance With Linux 6.3's New AMD P-State EPP Driver

Written by Michael Larabel in Software on 12 April 2023 at 01:00 PM EDT. Page 6 of 6. 34 Comments.

Arguably most interesting from this mess of CPU frequency scaling driver / governor / EPP combinations was the strong showing of amd_pstate_epp powersave with the power EPP. Often yielding the best performance-per-Watt was the classic acpi-cpufreq driver with the powersave governor, but often coming in second place and distinctly different than the remaining ten combinations was amd_pstate_epp powersave power. With amd_pstate_epp powersave power is some power savings advantage but not with losing half the performance or so as the big performance hits seen when using acpi-cpufreq powersave. Making use of the powersave governor with the AMD P-State EPP driver new to Linux 6.3 at least with this Lenovo ThinkPad X13 Gen3 with Ryzen 7 PRO 6850U was a nice trade of raw performance and power-savings.

CPU Peak Freq (Highest CPU Core Frequency) Monitor benchmark with settings of Phoronix Test Suite System Monitoring.

When looking at the peak CPU frequency on a one second polling basis over the course of all the benchmarks run, amd_pstate powersave never broke 414MHz on its fastest core and thus the very poor raw performance. With ACPI CPUFreq powersave the Ryzen 7 PRO 6850U never clocked above 1.6GHz. Or with the amd_pstate_epp powersave configuration it was running on average at 2.97GHz compared to the other configurations with an average peak frequency of 3.2~3.5GHz. Even when in amd_pstate_epp powersave power mode, at times this configuration still could successfully boost to 4.7GHz like the other more performance-minded configurations.

CPU Power Consumption Monitor benchmark with settings of Phoronix Test Suite System Monitoring.

The CPU/SoC power consumption over the span of all the benchmarks run shows amd_pstate_epp powersave on average pulling 1~3 Watts less than the other configurations besides the slow amd_pstate/acpi-cpufreq powersave modes.

CPU Temperature Monitor benchmark with settings of Phoronix Test Suite System Monitoring.

Besides saving power consumption and extending battery life when on battery, the amd_pstate_epp powersave mode led to slightly lower CPU core operating temperatures too.

Geometric Mean Of All Test Results benchmark with settings of Result Composite, AMD Ryzen 7 PRO 6850U AMD P-State Linux 6.3. amd_pstate_epp performance performance was the fastest.

If wanting decent performance but aiming to maximize your power efficiency, with AMD Rembrant Ryzen Mobile hardware at least the amd_pstate_epp powersave mode with Linux 6.3 is being a nice fit while not as performance-crippling as the other powersave options. Yielding the best performance overall was the AMD P-State performance mode, to no real surprise.

Those wanting to see even more data can find nearly 100 benchmarks in this result file along with the associated per-test power/thermal/frequency metrics.

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About The Author
Michael Larabel

Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via MichaelLarabel.com.