linux-kernel - Re: [PATCH v4 0/4] Update Energy Model after chip binning adjusted voltages

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Date: Wed, 3 Apr 2024 13:36:29 +0100
From: Lukasz Luba <lukasz.luba@....com>
To: Dietmar Eggemann <dietmar.eggemann@....com>
Cc: linux-arm-kernel@...ts.infradead.org, sboyd@...nel.org,
 rafael@...nel.org, linux-pm@...r.kernel.org, nm@...com,
 linux-samsung-soc@...r.kernel.org, daniel.lezcano@...aro.org,
 viresh.kumar@...aro.org, krzysztof.kozlowski@...aro.org,
 alim.akhtar@...sung.com, m.szyprowski@...sung.com, mhiramat@...nel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 0/4] Update Energy Model after chip binning adjusted
 voltages

Hi Dietmar,

On 4/3/24 13:07, Dietmar Eggemann wrote:
> On 02/04/2024 17:58, Lukasz Luba wrote:
>> Hi all,
>>
>> This is a follow-up patch aiming to add EM modification due to chip binning.
>> The first RFC and the discussion can be found here [1].
>>
>> It uses Exynos chip driver code as a 1st user. The EM framework has been
>> extended to handle this use case easily, when the voltage has been changed
>> after setup. On my Odroid-xu4 in some OPPs I can observe ~20% power difference.
>> According to that data in driver tables it could be up to ~29%.
>>
>> This chip binning is applicable to a lot of SoCs, so the EM framework should
>> make it easy to update. It uses the existing OPP and DT information to
>> re-calculate the new power values.
>>
>> It has dependency on Exynos SoC driver tree.
>>
>> Changes:
>> v4:
>> - added asterisk in the comment section (test robot)
>> - change the patch 2/4 header name and use 'Refactor'
>> v3:
>> - updated header description patch 2/4 (Dietmar)
>> - removed 2 sentences from comment and adjusted in patch 3/4 (Dietmar)
>> - patch 4/4 re-phrased code comment (Dietmar)
>> - collected tags (Krzysztof, Viresh)
>> v2:
>> - removed 'ret' from error message which wasn't initialized (Christian)
>> v1:
>> - exported the OPP calculation function from the OPP/OF so it can be
>>    used from EM fwk (Viresh)
>> - refactored EM updating function to re-use common code
>> - added new EM function which can be used by chip device drivers which
>>    modify the voltage in OPPs
>> RFC is at [1]
>>
>> Regards,
>> Lukasz Luba
>>
>> [1] https://lore.kernel.org/lkml/20231220110339.1065505-1-lukasz.luba@arm.com/
>>
>> Lukasz Luba (4):
>>    OPP: OF: Export dev_opp_pm_calc_power() for usage from EM
>>    PM: EM: Refactor em_adjust_new_capacity()
>>    PM: EM: Add em_dev_update_chip_binning()
>>    soc: samsung: exynos-asv: Update Energy Model after adjusting voltage
>>
>>   drivers/opp/of.c                 |  17 +++--
>>   drivers/soc/samsung/exynos-asv.c |  11 +++-
>>   include/linux/energy_model.h     |   5 ++
>>   include/linux/pm_opp.h           |   8 +++
>>   kernel/power/energy_model.c      | 106 +++++++++++++++++++++++++------
>>   5 files changed, 122 insertions(+), 25 deletions(-)
> 
> LGTM.
> 
> Just two very minor things which I mentioned in the individual patches.
> 
> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@....com>
> 
> 
> 

Thank you for the review. I will send the v5 with those.

Regards,
Lukasz