linux-kernel - Re: [RFC PATCH v2 0/1] cpuidle: teo: Introduce optional util-awareness

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Message-ID: <CAAYoRsXgmwQXNzDPgVe=_cW=C8_7__GYHCyRKkfX=6dFY9dybw@mail.gmail.com>
Date:   Thu, 6 Oct 2022 17:06:58 -0700
From:   Doug Smythies <dsmythies@...us.net>
To:     Kajetan Puchalski <kajetan.puchalski@....com>
Cc:     rafael@...nel.org, daniel.lezcano@...aro.org, lukasz.luba@....com,
        Dietmar.Eggemann@....com, yu.chen.surf@...il.com,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Doug Smythies <dsmythies@...us.net>
Subject: Re: [RFC PATCH v2 0/1] cpuidle: teo: Introduce optional util-awareness

On Mon, Oct 3, 2022 at 7:49 AM Kajetan Puchalski
<kajetan.puchalski@....com> wrote:
>
> Hi,
>
> At the moment, all the available idle governors operate mainly based on their own past performance
> without taking into account any scheduling information.

...

I tried V2 on my Intel i5-10600K, but there was little difference when
compared to V1 in terms of enormous increase in processor power
consumption for the periodic type tests I ran. However, sometimes the
power use would drop down to comparable to the normal teo or menu
governors for a short time, which V1 didn't do.

I would suggest a completely new governor for your
only 2 idle states, and of similar power use, scenario.
Incredibly simple:

If CPU utilization >= threshold
  select idle state 0
Else
  Select idle state 1
Endif

As previously mentioned, you are overriding
everything that teo does anyhow.

Note to other readers: I also sent Kajetan an off-list email with more
tests descriptions and web links to results graphs and such.

... Doug