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

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Date:   Thu, 26 Nov 2020 14:09:37 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Lukasz Luba <lukasz.luba@....com>
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

On 26/11/2020 13:49, Lukasz Luba wrote:
> 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.

Actually, I'm waiting for Ionela and Dietmar ack.


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