linux-kernel - Re: [PATCH v1 0/5] cpuidle: teo: Rework the idle state selection logic

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Date:   Thu, 29 Jul 2021 20:36:49 -0700
From:   Doug Smythies <dsmythies@...us.net>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        dsmythies <dsmythies@...us.net>
Subject: Re: [PATCH v1 0/5] cpuidle: teo: Rework the idle state selection logic

On Thu, Jul 29, 2021 at 9:14 AM Rafael J. Wysocki <rjw@...ysocki.net> wrote:
>
... [snip]...
>
> This means that idle state 0 data are disregarded after disabling it
> and that most likely is because the second loop in teo_select() should
> be over all states down to idle state 0 (not only down to the first
> enabled one).
>
> So below is an updated patch (not tested yet).

Hi Rafael,

This updated patch works great / solves the problem.
Tested-by: Doug Smythies <dsmythies@...us.net>

Thank you very much.

... Doug

>
> ---
>  drivers/cpuidle/governors/teo.c |   28 +++++++++++++++-------------
>  1 file changed, 15 insertions(+), 13 deletions(-)
>
> Index: linux-pm/drivers/cpuidle/governors/teo.c
> ===================================================================
> --- linux-pm.orig/drivers/cpuidle/governors/teo.c
> +++ linux-pm/drivers/cpuidle/governors/teo.c
> @@ -397,32 +397,34 @@ static int teo_select(struct cpuidle_dri
>                 intercept_sum = 0;
>                 recent_sum = 0;
>
> -               for (i = idx - 1; i >= idx0; i--) {
> +               for (i = idx - 1; i >= 0; i--) {
>                         struct teo_bin *bin = &cpu_data->state_bins[i];
>                         s64 span_ns;
>
>                         intercept_sum += bin->intercepts;
>                         recent_sum += bin->recent;
>
> -                       if (dev->states_usage[i].disable)
> +                       if (dev->states_usage[i].disable && i > 0)
>                                 continue;
>
>                         span_ns = teo_middle_of_bin(i, drv);
> -                       if (!teo_time_ok(span_ns)) {
> -                               /*
> -                                * The current state is too shallow, so select
> -                                * the first enabled deeper state.
> -                                */
> -                               duration_ns = last_enabled_span_ns;
> -                               idx = last_enabled_idx;
> -                               break;
> -                       }
>
>                         if ((!alt_recent || 2 * recent_sum > idx_recent_sum) &&
>                             (!alt_intercepts ||
>                              2 * intercept_sum > idx_intercept_sum)) {
> -                               idx = i;
> -                               duration_ns = span_ns;
> +                               if (!teo_time_ok(span_ns) ||
> +                                   dev->states_usage[i].disable) {
> +                                       /*
> +                                        * The current state is too shallow or
> +                                        * disabled, so select the first enabled
> +                                        * deeper state.
> +                                        */
> +                                       duration_ns = last_enabled_span_ns;
> +                                       idx = last_enabled_idx;
> +                               } else {
> +                                       idx = i;
> +                                       duration_ns = span_ns;
> +                               }
>                                 break;
>                         }