linux-kernel - Re: [PATCH v5 00/23] Introduce runtime modifiable Energy Model

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Message-ID: <6479439f-181f-4c99-b8ae-72fe2ee569ee@arm.com>
Date:   Wed, 13 Dec 2023 13:40:54 +0000
From:   Hongyan Xia <hongyan.xia2@....com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Lukasz Luba <lukasz.luba@....com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        dietmar.eggemann@....com, amit.kucheria@...durent.com,
        amit.kachhap@...il.com, daniel.lezcano@...aro.org,
        viresh.kumar@...aro.org, pavel@....cz, mhiramat@...nel.org,
        qyousef@...alina.io, wvw@...gle.com,
        Morten Rasmussen <morten.rasmussen@....com>,
        Ionela Voinescu <ionela.voinescu@....com>,
        Beata Michalska <Beata.Michalska@....com>,
        Sumit Gupta <sumitg@...dia.com>
Subject: Re: [PATCH v5 00/23] Introduce runtime modifiable Energy Model

Hi Rafael,

On 12/12/2023 18:49, Rafael J. Wysocki wrote:
> Hi Lukasz,
> 
> On Wed, Nov 29, 2023 at 12:08 PM Lukasz Luba <lukasz.luba@....com> wrote:
>>
>> [...]
> 
> I like this one more than the previous one and thanks for taking my
> feedback into account.
> 
> I would still like other people having a vested interest in the EM to
> look at it and give feedback (or just tags), so I'm not inclined to
> apply it just yet.  However, I don't have any specific comments on it.

I do have a keen interest in this series, but mostly from the point of 
view of uclamp. Currently uclamp is able to send hint the scheduler to 
bias task placement. Some CPU cores are known to have very different 
energy efficiency depending on the task. We know these tasks beforehand 
and can use uclamp to bias to certain CPUs which we know are more 
efficient for them.

Personally I've always been wondering if this could just be reflected in 
the EM itself without emphasizing on the task placement aspect of 
uclamp. The idea of this series LGTM and I'll take a deeper look.

Hongyan