linux-kernel - Re: [RFT][PATCH v2 0/3] cpuidle: teo: Do not check timers unconditionally every time

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Date:   Mon, 7 Aug 2023 18:46:37 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Kajetan Puchalski <kajetan.puchalski@....com>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Anna-Maria Behnsen <anna-maria@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>,
        Frederic Weisbecker <frederic@...nel.org>
Subject: Re: [RFT][PATCH v2 0/3] cpuidle: teo: Do not check timers
 unconditionally every time

Hi Kajetan,

On Mon, Aug 7, 2023 at 4:04 PM Kajetan Puchalski
<kajetan.puchalski@....com> wrote:
>
> Hi Rafael,
>
> On Thu, Aug 03, 2023 at 10:57:04PM +0200, Rafael J. Wysocki wrote:
> > Hi Folks,
> >
> > This is the second iteration of:
> >
> > https://lore.kernel.org/linux-pm/4511619.LvFx2qVVIh@kreacher/
> >
> > with an additional patch.
> >
> > There are some small modifications of patch [1/3] and the new
> > patch causes governor statistics to play a role in deciding whether
> > or not to stop the scheduler tick.
> >
> > Testing would be much appreciated!
> >
> > Thanks!
> >
>
> My test results including the v2 are below.
>
> 1. Geekbench 6
>
> +---------------------------+---------------+-----------------+-------------------+----------------------+
> |          metric           |      teo      |     teo_tick    |    teo_tick_rfc   |    teo_tick_rfc_v2   |
> +---------------------------+---------------+-----------------+-------------------+----------------------+
> |      multicore_score      | 3320.9 (0.0%) | 3303.3 (-0.53%) |  3293.6 (-0.82%)  |   3302.3 (-0.56%)    |
> |           score           | 1415.7 (0.0%) | 1417.7 (0.14%)  |  1423.4 (0.54%)   |    1425.8 (0.71%)    |
> |      CPU_total_power      | 2421.3 (0.0%) | 2429.3 (0.33%)  |  2442.2 (0.86%)   |    2461.9 (1.67%)    |
> |  latency (AsyncTask #1)   | 49.41μ (0.0%) | 51.07μ (3.36%)  |   50.1μ (1.4%)    |    50.76μ (2.73%)    |
> | latency (labs.geekbench6) | 65.63μ (0.0%) | 77.47μ (18.03%) | 55.82μ (-14.95%)  |    66.12μ (0.75%)    |
> | latency (surfaceflinger)  | 39.46μ (0.0%) | 36.94μ (-6.39%) |  35.79μ (-9.28%)  |    40.36μ (2.3%)     |
> +---------------------------+---------------+-----------------+-------------------+----------------------+
>
> +----------------------+-------------+------------+
> |         tag          |    type     | count_perc |
> +----------------------+-------------+------------+
> |         teo          |  too deep   |   2.034    |
> |       teo_tick       |  too deep   |    2.16    |
> |     teo_tick_rfc     |  too deep   |   2.071    |
> |    teo_tick_rfc_v2   |  too deep   |   2.548    |
> |         teo          | too shallow |   15.791   |
> |       teo_tick       | too shallow |   20.881   |
> |     teo_tick_rfc     | too shallow |   20.337   |
> |    teo_tick_rfc_v2   | too shallow |   19.886   |
> +----------------------+-------------+------------+
>
>
> 2. JetNews
>
> +-----------------+---------------+----------------+-----------------+-----------------+
> |     metric      |      teo      |    teo_tick    |  teo_tick_rfc   | teo_tick_rfc_v2 |
> +-----------------+---------------+----------------+-----------------+-----------------+
> |       fps       |  86.2 (0.0%)  |  86.4 (0.16%)  |  86.0 (-0.28%)  |  86.6 (0.41%)   |
> |    janks_pc     |  0.8 (0.0%)   |  0.8 (-0.66%)  |  0.8 (-1.37%)   |  0.7 (-11.37%)  |
> | CPU_total_power | 185.2 (0.0%)  | 178.2 (-3.76%) |  182.2 (-1.6%)  | 169.4 (-8.53%)  | <- very interesting
> +-----------------+---------------+----------------+-----------------+-----------------+
>
> +----------------------+-------------+--------------------+
> |         tag          |    type     |     count_perc     |
> +----------------------+-------------+--------------------+
> |         teo          |  too deep   |       0.992        |
> |       teo_tick       |  too deep   |       0.945        |
> |     teo_tick_rfc     |  too deep   |       1.035        |
> |    teo_tick_rfc_v2   |  too deep   |       1.127        |
> |         teo          | too shallow |       17.085       |
> |       teo_tick       | too shallow |       15.236       |
> |     teo_tick_rfc     | too shallow |       15.379       |
> |    teo_tick_rfc_v2   | too shallow |       15.34        |
> +----------------------+-------------+--------------------+
>
> All in all looks pretty good. Unfortunately there's a slightly larger
> percentage of too deep sleeps with the v2 (which is probably where the
> increase in GB6 power usage comes from) but the lower jank percentage +
> substantially lower power usage for the UI workload are very promising.
>
> Since we don't care about GB6 power usage as much as UI power usage, I'd
> say that the patchset looks good :)
>
> Tested-by: Kajetan Puchalski <kajetan.puchalski@....com>

Thanks a lot, much appreciated!