AMD Posts Latest Revision To Its New P-State Linux Driver

[phoronix]

Phoronix: AMD Posts Latest Revision To Its New P-State Linux Driver

In early September AMD posted their new "amd-pstate" CPU frequency scaling driver for Linux that leverages ACPI CPPC data available with Zen 2 and newer processors for making wiser frequency scaling decisions. The goal of AMD P-State is to offer better performance-per-Watt and today they have posted a new revision of this driver...

https://www.phoronix.com/scan.php?page=news_item&px=AMD-P-State-Linux-v3

[rodrigorras]

How Can I install those in Ubuntu 21?

[Linuxxx]

New to the amd-pstate v3 series is a patch from Valve to allow using SystemIO for _CPC registers. This patch should help some platforms like the ASUS Zephyrus G15 that use a SystemIO register for the highest performance _CPC element.

Really optimistic to read that VALVe is already testing this new CPU driver not only on their own Steam Deck but also on other gaming-focused hardware!

Now let's just hope that the performance with "schedutil" also keeps on improving, since Micheal's first round of testing had quite disappointing results there and SteamOS 3 will default to this CPU governor, at least on AMD hardware.

[flower]

How Can I install those in Ubuntu 21?

Wait until ubuntu releases a new kernel (probably 22.04)
or built it yourself

[smitty3268]

Really optimistic to read that VALVe is already testing this new CPU driver not only on their own Steam Deck but also on other gaming-focused hardware!

Now let's just hope that the performance with "schedutil" also keeps on improving, since Micheal's first round of testing had quite disappointing results there and SteamOS 3 will default to this CPU governor, at least on AMD hardware.

My understanding is that the p-state driver can also be used for other governors besides just schedutil. So it should provide benefits even if you are using ondemand.

[shmerl]

Is it a good drop in replacement for current usage of schedutil? I.e. it makes power usage better supposedly, but it doesn't make performance worse I hope? Some benchmarks would be good.

[brucethemoose]

Really optimistic to read that VALVe is already testing this new CPU driver not only on their own Steam Deck but also on other gaming-focused hardware!

Now let's just hope that the performance with "schedutil" also keeps on improving, since Micheal's first round of testing had quite disappointing results there and SteamOS 3 will default to this CPU governor, at least on AMD hardware.

IIRC that was tested on high TDP hardware. Extremely power constrained chips can behave differently, where even the performance governor performs worse than schedutil because the processor eats too much power to maintain boost clocks, or maintain high IGP clocks.

[Linuxxx]

My understanding is that the p-state driver can also be used for other governors besides just schedutil. So it should provide benefits even if you are using ondemand.

But most people just stick to the defaults, so anyone with an AMD CPU that decides to try out SteamOS 3 will unknowingly rely on "schedutil" doing its job properly (i.e. smooth & stutter-free gameplay).

[Linuxxx]

Is it a good drop in replacement for current usage of schedutil? I.e. it makes power usage better supposedly, but it doesn't make performance worse I hope? Some benchmarks would be good.

https://www.phoronix.com/scan.php?page=article&item=amd-pstate-first&num=1

Early results are not that promising, unfortunately...

[Linuxxx]

IIRC that was tested on high TDP hardware. Extremely power constrained chips can behave differently, where even the performance governor performs worse than schedutil because the processor eats too much power to maintain boost clocks, or maintain high IGP clocks.

True, that's the reason why Android smartphones rooted & switched over to make use of the 'performance' governor are worse for games than 'schedutil', especially so for longer sessions.

But on high TDP chips 'schedutil' should come as close as possible to the results of 'performance', ideally.