switch between cpu power configurations depending on the current workload

[monarc99]

I would like to test to switch power configs on current workload or something similar.

e.g. mpv Video Player

if it plays a video and use hardware decoding, it does not need much cpu power -> powersave profile
But if it has to play a 8K AV1 Video, no HW support for AV1, it falls back to software decoding -> performance profile

Do you plan to add switching on usage? (i am not sure, if usage is the best value for it - e.g. single core program, that utilise only 1 core with 100%, other 1-2%)

[Haptein]

Right now I'm implementing a system to track performance states across time (SystemStatus branch) which is needed to implement this kind of features.

Do you plan to add switching on usage?

I am interested in implementing this kind of feature. It would be simple to implement a system that switches gears depending on per core cpu load, for example switching policies or governors depending of load. The complexity of it comes in designing it in a way that is simple to configure and is available to multiple scaling drivers. I was thinking on dynamically changing the maximum frequency allowed instead of governors/policy, what do you think about this approach in the context of your usecases? Still, I'm all for experimenting 🧪

[monarc99]

So always performance gov, but with limited freq? Turbo?

I have two usecases.

On AC - save power if idle, but performance is more important. Even on lower usage, switch to max freq/policy/governor. Really quick.
On BAT - save power. I would change max. freq only on really high usage (on several cores?).

[monarc99]

And i think you can expect the Power Profiles Daemon on every KDE/Gnome system in the future.
Maybe powerplan could use it. e.g. automatic switching the power profile daemon.

[Haptein]

So always performance gov, but with limited freq? Turbo?

I was thinking on having a "dynamic_frequency_limiter" or something similar as a toggle, available just like any other profile entry. So people can experiment and find what works best for different preference/use cases(and with enough feedback documenting a guide with recommendations sounds reasonable).

And i think you can expect the Power Profiles Daemon on every KDE/Gnome system in the future. Maybe powerplan could use it. e.g. automatic switching the power profile daemon.

I think ppd it's a nice project, but in the context of powerplan I worry about the interference between the two. I think ppd's approach ppd is a bit simplistic compared to what I'd personally like to use as it currently only offers a couple presets, I'd have to see a roadmap tho. With intel_pstate for example, ppd only switches policies, and it ought to use the same sysfs interface used here. The only reason I see to interact with ppd (at least right now) is to make sure it's in line with the current profile applied by powerplan.

On the other hand, I had the idea of releasing a rust rewrite of this project once it's codebase stabilizes, so I guess submitting some code to ppd in the future is not out of the question either, how far off in the future I don know tho.