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

[Mario Limonciello <superm1@kernel.org>]

On 9/30/26 14:37, Rafael J. Wysocki (Intel) wrote:
> On Fri, Sep 25, 2026 at 4:54 PM Mario Limonciello <superm1@kernel.org> 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@amd.com>
>>>>
>>>> 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.

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.