For example, in case of schedutil this value depends on the current utilization. In guided autonomous mode the min_perf is based on the input from the scaling governor. Guided autonomous: OS scaling governor specifies min and max frequencies/ performance levels through Minimum Performance and Maximum Performance register, and PMFW can autonomously select an operating frequency in this range.įully autonomous: OS only hints (via EPP) to PMFW for the required energy performance preference for the workload and PMFW autonomously scales the frequency.Ĭurrently (1) is supported by amd_pstate as passive mode, and (3) is implemented by EPP support. Non autonomous: OS scaling governor specifies operating frequency/performance level through Desired Performance register and PMFW follows that. The notes from the guided-autonomous patch series have been the most helpful to me so far:įrom ACPI spec below 3 modes for CPPC can be defined:

And my cores are idling down to 550 MHz, which is great! Now I can easily enable amd_pstate and it works as expected. After some trial and error I found the culprit… I had enabled X2APIC on both X570 systems a few weeks ago to see if it was stable and working well enough to daily drive. So then I moved on to the next phase: trying to figure out which wacky BIOS setting I enabled that basically broke a big piece of ACPI.

When I got back into Linux, I noticed right away that my cores were idling down to 2200 MHz (IIRC) and-et voilà!-/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver was showing acpi_cpufreq again. I went back into the BIOS, loaded optimal settings, then did a very basic config just to get my system posting again.

And my test bench with an Asus Pro WS X570-ACE with a 3900X is having all of the same issues as well (and idling down to 3700 MHz, even in Windows). In addition to the above symptoms, I also noticed that my cores were idling down to 3400 MHz, which seemed a bit high. acpi_cpufreq, scaling_governor, energy_performance_preference, etc.

There is literally nothing happening in the kernel for e.g.

Instal the new Geekbench Pro 6.1.0