Re: [PATCH 0/4] platform/x86/amd/pmf: Introduce CnQF feature for AMD PMF

[Bastien Nocera <bnocera@redhat.com>]

On Wed, 7 Sept 2022 at 16:35, Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi Bastien,
>
> On 9/7/22 16:24, Bastien Nocera wrote:
> > Hey Shyam,
> >
> > I misunderstood that CnQF was a single setting, but it looks like it
> > has 4 different levels, right?
> > Unless there's a major malfunction, I don't think that offering to
> > switch between 2 different policies where the difference is how
> > "static" the performance boosts are is very useful, or comprehensible,
> > to end-users.
> >
> > If CnQF only has a single "on" setting, then this could replace the
> > balanced mode for what you call "static slider", so the end-user can
> > still make a choice and have agency on whether the system tries to
> > save power, or increase performance.
> >
> > If CnQF has multiple levels (Turbo, Performance, Balanced and Quiet,
> > right?), then I don't think it's useful to have a sysfs setting to
> > switch it at runtime, which only confuses user-space and the users.
> > BIOS setting and/or kernel command-line option are the way to go.
> >
> > Did I understand this correctly?
>
> Let me try clarify things:
>
> CnQF has 4 levels internally, between which it switches automatically
> based on the workload of the last 5 minutes.

Oh, those profiles are internal only, OK. Do those automated levels
behave like the "static slider" ones, to the point of being
indistinguishable? So for example, does the static slider
"performance" behave like "CnQF" if the machine was heavily loaded
machine for 5 minutes?