linux-kernel - Re: [PATCH v6 2/2] thermal/debugfs: Add thermal debugfs information for mitigation episodes

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Date: Tue, 9 Jan 2024 14:28:27 +0100
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: rjw@...ysocki.net, lukasz.luba@....com, rui.zhang@...el.com,
 linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v6 2/2] thermal/debugfs: Add thermal debugfs information
 for mitigation episodes

On 09/01/2024 14:02, Rafael J. Wysocki wrote:
> On Tue, Jan 9, 2024 at 10:41 AM Daniel Lezcano
> <daniel.lezcano@...aro.org> wrote:
>>
>> The mitigation episodes are recorded. A mitigation episode happens
>> when the first trip point is crossed the way up and then the way
>> down. During this episode other trip points can be crossed also and
>> are accounted for this mitigation episode. The interesting information
>> is the average temperature at the trip point, the undershot and the
>> overshot. The standard deviation of the mitigated temperature will be
>> added later.
>>
>> The thermal debugfs directory structure tries to stay consistent with
>> the sysfs one but in a very simplified way:
>>
>> thermal/
>>   `-- thermal_zones
>>       |-- 0
>>       |   `-- mitigations
>>       `-- 1
>>           `-- mitigations
>>
>> The content of the mitigations file has the following format:
>>
>> ,-Mitigation at 349988258us, duration=130136ms
>> | trip |     type | temp(°mC) | hyst(°mC) |  duration  |  avg(°mC) |  min(°mC) |  max(°mC) |
>> |    0 |  passive |     65000 |      2000 |     130136 |     68227 |     62500 |     75625 |
>> |    1 |  passive |     75000 |      2000 |     104209 |     74857 |     71666 |     77500 |
>> ,-Mitigation at 272451637us, duration=75000ms
>> | trip |     type | temp(°mC) | hyst(°mC) |  duration  |  avg(°mC) |  min(°mC) |  max(°mC) |
>> |    0 |  passive |     65000 |      2000 |      75000 |     68561 |     62500 |     75000 |
>> |    1 |  passive |     75000 |      2000 |      60714 |     74820 |     70555 |     77500 |
>> ,-Mitigation at 238184119us, duration=27316ms
>> | trip |     type | temp(°mC) | hyst(°mC) |  duration  |  avg(°mC) |  min(°mC) |  max(°mC) |
>> |    0 |  passive |     65000 |      2000 |      27316 |     73377 |     62500 |     75000 |
>> |    1 |  passive |     75000 |      2000 |      19468 |     75284 |     69444 |     77500 |
>> ,-Mitigation at 39863713us, duration=136196ms
>> | trip |     type | temp(°mC) | hyst(°mC) |  duration  |  avg(°mC) |  min(°mC) |  max(°mC) |
>> |    0 |  passive |     65000 |      2000 |     136196 |     73922 |     62500 |     75000 |
>> |    1 |  passive |     75000 |      2000 |      91721 |     74386 |     69444 |     78125 |
>>
>> More information for a better understanding of the thermal behavior
>> will be added after. The idea is to give detailed statistics
>> information about the undershots and overshots, the temperature speed,
>> etc... As all the information in a single file is too much, the idea
>> would be to create a directory named with the mitigation timestamp
>> where all data could be added.
>>
>> Please note this code is immune against trip ordering but not against
>> a trip temperature change while a mitigation is happening. However,
>> this situation should be extremely rare, perhaps not happening and we
>> might question ourselves if something should be done in the core
>> framework for other components first.
>>
>> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
> 
> Both patches in the series look good to me now, so I'll queue them up
> for 6.8-rc1.

Great, thanks !

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