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

[Shyam Sundar S K <Shyam-sundar.S-k@amd.com>]

Hi Bastien,

On 9/8/2022 2:38 PM, Hans de Goede wrote:
> Hi,
> 
> On 9/7/22 17:35, Bastien Nocera wrote:
>> 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?
> 
> This is more of a question for AMD to answer. But yes I believe that
> the CnQF internal performance mode which it boosts to if the machine
> is heavily loaded for 5 minutes is similar to the static slider
> performance setting.

Its a kind of "yes". But its still dependent on how the OEMs have tuned
the power profiling values and mapped it to the relavant CnQF modes.

Thanks,
Shyam

> 
> Regards,
> 
> Hans
>