AMD Posts 11th Iteration Of P-State Preferred Core Patches For Linux

[cj.wijtmans]

Yeah

I've used Gentoo in the past.

Ended up settling for Arch Linux.. Gentoo will have to wait until I get a Threadripper

really? on gentoo a patch is as simple as dropping in path file and rebuild. What is easier about PKGBUILD?

[Kjell]

nope.

Yeah

I've used Gentoo in the past.

Ended up settling for Arch Linux.. Gentoo will have to wait until I get a Threadripper

[cj.wijtmans]

It was even easier with Arch Linux's PKGBUILD

nope.

[Kjell]

Gentoo makes patching easy.

It was even easier with Arch Linux's PKGBUILD

[geearf]

On my 59xx Notebook I have all options available but the lowest power usage is on 'passive' (6 Watt) compared to 'active'/'guided' (around 10 Watt). That's significant.

Yeah for a notebook it's very significant! I am on desktop so I am more interested by efficiency than pure power usage.
Thank you!

[reba]

Is guided 'better' than active?

On my 59xx Notebook I have all options available but the lowest power usage is on 'passive' (6 Watt) compared to 'active'/'guided' (around 10 Watt). That's significant.

[cj.wijtmans]

Ty, That's a little above my pay grade I have no idea I'll just wait till the kernel comes out Thank you for letting me know

Gentoo makes patching easy.

[unwind-protect]

Is there a chapter in the AMD reference manuals about how to talk to the processor about preferred cores or is it all done ad-hoc by AMD insiders?

[unwind-protect]

One thing I don't understand about preferred core:

So the scheduler listens to the processor for recommendations about which core to use.

How does that work for different kinds of threads? Obviously some threads would want other cores than other threads. Does the scheduler tell the processor what kind of thread is incoming? Does the processor maintain state about what thread did what in the past?

[geearf]

It's enabled by default on CachyOS and can be checked at

❯cat /sys/devices/system/cpu/amd_pstate/prefcore
enabled

That's using amd_pstate=guided in the command line with schedutil as the governor.

Is guided 'better' than active?