AMD 8700G CPU Governors

rsnfunky · Tux's lil' helper Joined: 30 Dec 2007 Posts: 121

Hi,

I have an AMD 8700G (A fairly recent processor). I wanted to set the 'OnDemand' Governor.

I had build the Kernel 6.14 and have built all CPU governors:

blu3bird · Posted: Sat Apr 12, 2025 8:12 am Post subject:

A long time ago the kernel/governor would actively managed a CPUs frequency. For instance the ondemand governor would increase/decrease the frequency depending on the systems load. That's probably what you are referring to when you use the term ondemand.

Turns out having the operating system control the CPU frequency doesn't really work that well. It's far better to let the CPU itself control it's own frequency and just have the operating system provide some parameters on how the CPU should do that.

That's what the pstate driver (both amd pstate and intel pstate) does. It does not directly control the CPUs frequency it just provides parameters on how the CPU should operate.

The cpupower program is one way to manage these parameter but since it was designed ages ago and wants to remain compatible with older CPUs it's using terms like governor that are technically incorrect for modern CPUs. You can check out /sys/devices/system/cpu/cpu*/cpufreq for a list of parameters your kernel offers to influence the CPU.

So long story short: Both the powersave and performance "governors" offered by cpupower are ondemand-like governors. One is tailored a bit more for powersaving, the for performance.

* this whole post is over-simplified
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Ralphred · l33t Joined: 31 Dec 2013 Posts: 779

Just as an addendum to blu3bird's post: As and avid gamer and user of AMD cpu's, the amd-pstate powersave governor is the first ever non-"performance" governor that doesn't introduce frametime spikes or noticeable periods of lag. When running at full load (when load average is ~= to nproc) there is no difference between the powersave and performance governors AFAICT. Maybe because the maximum boost clocks are applied when the "thermal opportunity" presents itself at times of need, I get a "higher average clock speed for working cores" using powersave than performance.

If you really want to use schedutil you can add amd_pstate=guided on the kernel command line, but that feels like replacing a modern car's ECU with a distributor...