linux-kernel - Re: [PATCH v4 0/3] Improve the estimations in Intelligent Power Allocation

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Message-ID: <e953e887-0fc7-8375-9e5d-1be339f48216@arm.com>
Date:   Thu, 26 Nov 2020 12:49:51 +0000
From:   Lukasz Luba <lukasz.luba@....com>
To:     daniel.lezcano@...aro.org
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        amitk@...nel.org, Dietmar.Eggemann@....com, ionela.voinescu@....com
Subject: Re: [PATCH v4 0/3] Improve the estimations in Intelligent Power
 Allocation

Hi Daniel,

On 11/24/20 4:10 PM, Lukasz Luba wrote:
> Hi all,
> 
> The Intelligent Power Allocation (IPA) estimates the needed coefficients for
> internal algorithm. It can also estimate the sustainable power value when the
> DT has not provided one. Fix the 'k_i' coefficient which might be to big
> related to the other values, when the sustainable power is in an abstract
> scale. Do the estimation of sustainable power only once and avoid expensive
> calculation every time the IPA is called. Do the estimation of PID constants
> when there was user update via sysfs to sustainable power.
> 
> The patch set should apply on top next-20201124
> 
> Changes:
> v4:
> - added new function get_sustainable_power() which handles use cases
>    when the value should be estimated again or simply returned
> - added sustainable_power in the power_allocator_params to track if there
>    was a change to sustainable_power by the user via sysfs
> - addressed Daniel's comments that sustainable power set via sysfs should
>    trigger PID coefficients estimation
> - removed 'force' argument from estimate_pid_constants() and make it ready
>    for updates due to new value for sust. power from sysfs
> - abandoned the design from v3 with a single function responsible for
>    estimation both sust. power and PID const. requested by Ionela
> v3 [1]:
> - changed estimate_pid_constants to estimate_tzp_constants and related comments
> - estimate the PID coefficients always together with sust. power
> - added print indicating that we are estimating sust. power and PID const.
> - don't use local variable 'sustainable_power'
> 
> Regards,
> Lukasz Luba
> 
> [1] https://lore.kernel.org/lkml/20201009135850.14727-1-lukasz.luba@arm.com/
> 
> Lukasz Luba (3):
>    thermal: power allocator: change the 'k_i' coefficient estimation
>    thermal: power allocator: refactor sustainable power estimation
>    thermal: power allocator: change the 'k_*' always in
>      estimate_pid_constants()
> 
>   drivers/thermal/gov_power_allocator.c | 76 +++++++++++++++++----------
>   1 file changed, 49 insertions(+), 27 deletions(-)
> 

Gentle ping. This is a self contained change to only power allocator
file. It addresses also your requirement regarding sustainable_power
changed via sysfs.

Could you take it please? It should apply smoothly in your tree.

Regards,
Lukasz