linux-kernel - Re: [PATCH 1/2] thermal: cooling: Check Energy Model type in cpufreq_cooling and devfreq

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Date:   Tue, 22 Feb 2022 23:10:51 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Lukasz Luba <lukasz.luba@....com>
Cc:     amit.kachhap@...il.com, viresh.kumar@...aro.org, rafael@...nel.org,
        amitk@...nel.org, rui.zhang@...el.com, dietmar.eggemann@....com,
        Pierre.Gondois@....com, Matthias Kaehlcke <mka@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] thermal: cooling: Check Energy Model type in
 cpufreq_cooling and devfreq_cooling


Hi Lukasz,

On 22/02/2022 19:31, Lukasz Luba wrote:
> 
> 
> On 2/22/22 18:12, Daniel Lezcano wrote:
>>
>> Hi Lukasz,
>>
>> I don't think it makes sense to remove the support of the energy model 
>> if the units are abstracts.
>>
>> IIUC, regarding your previous answer, we don't really know what will 
>> do the SoC vendor with these numbers and likely they will provide 
>> consistent abstract values which won't prevent a correct behavior.
>>
>> What would be the benefit of giving inconsistent abstract values which 
>> will be unusable except of giving a broken energy model?
> 
> The power values in the EM which has abstract scale, would make sense to 
> EAS, but not for IPA or DTPM. Those platforms which want to enable EAS,
> but don't need IPA, would register such '<a_good_name_here>' EM.

Sorry, but I don't understand why DTPM can not deal with abstract values?


>> Your proposed changes would be acceptable if the energy model has a 
>> broken flag IMO
> 
> That is doable. I can add that flag, so we can call it 'artificial' EM
> (when this new flag is set).

It is too soon IMO, I would like to see the numbers first so we can take 
an enlighten decision. Right now, it is unclear what the numbers will be.


> Let me craft the RFC patch with this new flag proposal then.
> Do you agree? Can I also add you as 'Suggested-by'?
> 
> Thank you for coming back to me with the comments.


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