linux-kernel - Re: [PATCH 0/4] Energy Model power in micro-Watts and SCMI v3.1 alignment

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Message-ID: <be793e51-0d89-7afd-e122-ec929a1130e9@arm.com>
Date:   Wed, 29 Jun 2022 10:49:26 +0100
From:   Lukasz Luba <lukasz.luba@....com>
To:     linux-pm@...r.kernel.org
Cc:     daniel.lezcano@...aro.org, amitk@...nel.org, rui.zhang@...el.com,
        viresh.kumar@...aro.org, rafael@...nel.org,
        dietmar.eggemann@....com, nm@...com, sboyd@...nel.org,
        sudeep.holla@....com, cristian.marussi@....com,
        matthias.bgg@...il.com, linux-mediatek@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/4] Energy Model power in micro-Watts and SCMI v3.1
 alignment

Hi guys,

Are there any objections to these patches?


On 6/22/22 15:57, Lukasz Luba wrote:
> Hi all,
> 
> This is a patch set which changes Energy Model power values scale to
> micro-Watts. It also upgrades the SCMI performance layer + scmi-cpufreq
> driver to leverage the SCMI v3.1 spec and process micro-Watts power values
> coming from FW. The higher precision in EM power field solves an issue
> of a rounding error, which then can be misinterpreted as 'inefficient OPP'.
> An example rounding issue calculation is present in patch 1/4 description.
> 
> Regards,
> Lukasz Luba
> 
> Lukasz Luba (4):
>    PM: EM: convert power field to micro-Watts precision and align drivers
>    Documentation: EM: Switch to micro-Watts scale
>    firmware: arm_scmi: Get detailed power scale from perf
>    cpufreq: scmi: Support the power scale in micro-Watts in SCMI v3.1
> 
>   Documentation/power/energy-model.rst  | 14 +++---
>   drivers/cpufreq/mediatek-cpufreq-hw.c |  7 +--
>   drivers/cpufreq/scmi-cpufreq.c        | 15 ++++++-
>   drivers/firmware/arm_scmi/perf.c      | 18 +++++---
>   drivers/opp/of.c                      | 15 ++++---
>   drivers/powercap/dtpm_cpu.c           |  5 +--
>   drivers/thermal/cpufreq_cooling.c     | 13 +++++-
>   drivers/thermal/devfreq_cooling.c     | 19 ++++++--
>   include/linux/energy_model.h          | 63 ++++++++++++++++++++-------
>   include/linux/scmi_protocol.h         |  8 +++-
>   kernel/power/energy_model.c           | 31 ++++++++-----
>   11 files changed, 146 insertions(+), 62 deletions(-)
> 


I would like to move forward with the micro-Watts in
the Energy Model. We have feedback from our partners
that this is a limitation. Also, as you can see
this uW is part of the new SCMI spec, which we
have support on our roadmap.

Regards,
Lukasz