linux-kernel - Re: [PATCH v2 0/3] Add basic tracing for uclamp and schedutil

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Date:   Mon, 22 May 2023 14:38:43 +0100
From:   Lukasz Luba <lukasz.luba@....com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     rostedt@...dmis.org, mhiramat@...nel.org, mingo@...hat.com,
        peterz@...radead.org, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, dietmar.eggemann@....com,
        bsegall@...gle.com, mgorman@...e.de, bristot@...hat.com,
        vschneid@...hat.com, delyank@...com, qyousef@...gle.com,
        qyousef@...alina.io, linux-kernel@...r.kernel.org,
        linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH v2 0/3] Add basic tracing for uclamp and schedutil

Hi Rafael,



On 5/9/23 13:22, Lukasz Luba wrote:
> Hi all,
> 
> The task scheduler feature: Uclamp, begins to take off. To better understand
> the dynamics in the task scheduler and CPU frequency requests we need some
> better tracing.
> In schedutil (cpufreq governor) we allow to enter the scheduler
> and make the frequency change. Although, there is some limit in regards to how
> often this can happen. That min period is provided by the cpufreq driver.
> Thus, some of the cpufreq requests might be filter out and the frequency won't
> be changed (hopefuly will be set a bit later). We would like to know about
> those situations, especially in context of the user-space hints made via
> Uclamp for particular tasks.
> This patch set aims to add base for our toolkits and post-processing trace
> analyzes.
> 
> Changelog:
> v2:
> - solved the issue from CI build warning, dropped schedutil.h and re-used
>    the sched.h which is available in build_utility.c where cpufreq_schedutil.c
>    is included
> - added tag for the last patch 3/3 for the CI robot helping hend
> - re-based on top of v6.4-rc1
> v1:
> - implementation can be found here [1]
> 

I was going to gently ping you, while I've realized that you
are not on CC list :( I don't know what happened, my apologies.

Shell I resend this patch set so you can have it in a proper way
in your mailbox?

Could you have a look at this, please?

This is getting more attention, since in Android we have a
daemon which can now communicate with the kernel and send
those Uclamp values on behalf of an unprivileged app.

Regards,
Lukasz