Re: [PATCH v3 1/3] ACPI: CPPC: Refactor boost ratio handling

[Rafael J. Wysocki (Intel)]

On Wed, Sep 30, 2026 at 9:41 PM Mario Limonciello <superm1@xxxxxxxxxx> wrote:
>
> On 9/30/26 14:37, Rafael J. Wysocki (Intel) wrote:
> > On Fri, Sep 25, 2026 at 4:54 PM Mario Limonciello <superm1@xxxxxxxxxx> wrote:
> >>
> >> On 9/25/26 04:40, Christian Loehle wrote:
> >>> On 9/24/26 17:00, Mario Limonciello (AMD) wrote:
> >>>> From: Mario Limonciello <mario.limonciello@xxxxxxx>
> >>>>
> >>>> Rename amd_get_boost_ratio_numerator() to amd_get_effective_highest_perf()
> >>>> to better reflect that it returns the effective highest performance value
> >>>> for a CPU, accounting for preferred cores and heterogeneous topologies.
> >>>>
> >>>> Add a new helper amd_get_boost_ratio() for doing both for boost
> >>>> ratio calculations and update callers to use it.
> >>>>
> >>>> This refactoring is needed because on some AMD systems (Zen6+),
> >>>> the boost ratio should be calculated from frequency values rather than
> >>>> performance values.
> >>>
> >>> I think I see why you chose to implement it this way (the x86 APERF / MPERF)
> >>> issue, but I'd still prefer it to be spelled out here why this is necessary.
> >>>
> >>
> >> Do you mean in the commit message, like spin the patch?  Or just in this
> >> thread?
> >>
> >> Not all cores will operate at the same frequency and fixed scaling
> >> values from CPPC perf don't apply anymore.
> >
> > Well, CPPC is per-CPU at least in principle, so the above doesn't
> > explain much TBH.
> >
> > It kind of follows from the cover letter that there's something
> > missing in CPPC, so this is a stop-gap thing, but it would be good to
> > put the information from the cover letter to the changelog of this
> > patch.
>
> OK; I'll respin the series with the detail in this commit message.

Thanks!

With that, please feel free to add my ACKs to the first two patches in
this series and route it as a whole through the amd-pstate tree.

> And yeah; this is totally stop gap to allow other development that needs
> this.
>
> Once next ACPI spec is out I'll tear out the stop gap and put in the
> right support.

OK