linux-kernel - Re: [PATCH v4 0/3] Improve IPA mechanisms in low temperature state

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <00e2b778-c00e-a0ba-cff4-e3be16d37805@arm.com>
Date:   Thu, 22 Apr 2021 18:33:00 +0100
From:   Lukasz Luba <lukasz.luba@....com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        amitk@...nel.org, rui.zhang@...el.com
Subject: Re: [PATCH v4 0/3] Improve IPA mechanisms in low temperature state



On 4/22/21 6:30 PM, Daniel Lezcano wrote:
> On 22/04/2021 13:43, Lukasz Luba wrote:
>> Hi all,
>>
>> This v4 patch set aims to address the issues present in IPA when the
>> temperature is below the first trip point and cooling devices are not
>> throttled.
>> The last patch 1/3 is co-developed by Daniel, who presented the code
>> during v2 review. I have created a helper function based on his idea,
>> which can now be used inside IPA governor lock protected code.
>> The patch 2/3 adds a basic check of cooling devices power to keep the
>> internal statistics fresh. This allows to avoid issue when the statistics
>> cover very long period, because they were not maintained.
>> The patch 3/3 addresses an issue described in bugzilla [1], which is:
>> unnecessary updating cooling devices when their state has not changed
>> because they are not throttled. This update triggers sending an event,
>> which should be avoided. Thus, patch 2/3 adds a tracking mechanism if
>> the update was triggered and makes sure it will be done only once when
>> the temperature continue to stay below first trip point.
>>
>> changelog:
>> v4:
>> - reordered the patches, patch 3/3 from v3 is now 1/3
>> v3:
>> - new patch 3/3 co-developed with Daniel
>> v2:
>> - patch 2/2 uses now simple 'update' bool flag and information from
>>    'tz->last_temperature'
>> - patch 1/2 has small change in the comment
>> - re-based on top of today's thermal/next branch
>>
>> Regards,
>> Lukasz Luba
>>
>> [1] https://bugzilla.kernel.org/show_bug.cgi?id=212501
>>
>> Lukasz Luba (3):
>>    thermal: create a helper __thermal_cdev_update() without a lock
>>    thermal: power_allocator: maintain the device statistics from going
>>      stale
>>    thermal: power_allocator: update once cooling devices when temp is low
>>
>>   drivers/thermal/gov_power_allocator.c | 21 +++++++++++++++++----
>>   drivers/thermal/thermal_core.h        |  1 +
>>   drivers/thermal/thermal_helpers.c     | 27 +++++++++++++++++----------
>>   3 files changed, 35 insertions(+), 14 deletions(-)
> 
> Applied, thanks
> 
> 

Thank you Daniel!

Regards,
Lukasz