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

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Date: Wed, 3 Apr 2024 14:07:30 +0200
From: Dietmar Eggemann <dietmar.eggemann@....com>
To: Lukasz Luba <lukasz.luba@....com>, linux-kernel@...r.kernel.org,
 linux-pm@...r.kernel.org, rafael@...nel.org
Cc: linux-arm-kernel@...ts.infradead.org, sboyd@...nel.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
Subject: Re: [PATCH v4 0/4] Update Energy Model after chip binning adjusted
 voltages

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>