AMD Posts "P-State EPP" Driver As New Attempt To Improve Performance-Per-Watt On Linux

[phoronix]

Phoronix: AMD Posts "P-State EPP" Driver As New Attempt To Improve Performance-Per-Watt On Linux

Over the past year AMD engineers have been developing the AMD P-State CPU frequency scaling driver as an alternative to the long-used ACPI CPUFreq driver to provide better performance/power efficiency with Zen 2 and newer Ryzen/EPYC processors. Today they have now introduced AMD P-State EPP as they aim to deliver better performance-per-Watt...

https://www.phoronix.com/news/AMD-P-State-EPP-Linux

[Lbibass]

Very exciting! This seems like it could be a great help to mobile devices like the Steam Deck as well.

[birdie]

Very exciting! This seems like it could be a great help to mobile devices like the Steam Deck as well.

I'm not sure about that. This news made me feel like they had given up on amd-pstate without finishing it and now they are on to another scheduler driver.

[Linuxxx]

I'm not sure about that. This news made me feel like they had given up on amd-pstate without finishing it and now they are on to another scheduler driver.

Yeah, it really sounds like this is intended to supersede AMD-PSTATE.

Then again, Intel already offers similar functionality for years, which can be queried with the following command:

sudo cpupower -c all info

Let's see how schedutil will fare in gaming with this one...

[shmerl]

I remember there was some comment in the code that it only worked for hardware that had some specific registers and without them there was too much latency to benefit from it. And apparently those registers were present only in AMD APUs, so for instance pure CPUs like Ryzen 9 5900X / 5950X couldn't really use it properly.

Will new high end 6000 CPUs have these registers?

[Linuxxx]

Actually, looks like schedutil is not even an option anymore with this new driver!

I wonder what this says about the quality of schedutil...

This driver is basically AMD's answer to Intel's Pstate driver, which also doesn't offer the option of schedutil by default, unless passing the following kernel parameter:

intel_pstate=passive

[V1tol]

I wonder what this says about the quality of schedutil...

Don't know about its quality, but switching to ondemand on my 5950X visibly improves performance in games for example.

[Linuxxx]

Don't know about its quality, but switching to ondemand on my 5950X visibly improves performance in games for example.

And the performance governor would certainly improve the performance even further!

Or at the very least, there wouldn't be any degredation...

[tachi]

In a world where energy is becoming increasingly important, I hope we'll go in a direction where we first try to optimize for efficiency, then for everything else - and I'm thus really grateful for AMD's P-state work

[imaami]

Don't know about its quality, but switching to ondemand on my 5950X visibly improves performance in games for example.

Is this with amd-pstate? How does the performance scheduler compare?

Also what kernel do you use? More specifically what CPU scheduler do you run and how are the sysfs parameters for ondemand tuned?