linux-kernel - Re: [RFC PATCH 09/16] sched/fair: util_est: Take into account periodic tasks

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Message-ID: <CANDhNCre2=8aHCgy9DNHkXix2Leu3MSDD7HRJp9wbrHBm+kNGg@mail.gmail.com>
Date: Tue, 12 Nov 2024 20:57:05 -0800
From: John Stultz <jstultz@...gle.com>
To: Qais Yousef <qyousef@...alina.io>
Cc: Ingo Molnar <mingo@...nel.org>, Peter Zijlstra <peterz@...radead.org>, 
	Vincent Guittot <vincent.guittot@...aro.org>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Viresh Kumar <viresh.kumar@...aro.org>, Juri Lelli <juri.lelli@...hat.com>, 
	Steven Rostedt <rostedt@...dmis.org>, Dietmar Eggemann <dietmar.eggemann@....com>, linux-pm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 09/16] sched/fair: util_est: Take into account
 periodic tasks

On Tue, Aug 20, 2024 at 9:36 AM Qais Yousef <qyousef@...alina.io> wrote:
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index a6421e4032c0..0c10e2afb52d 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4899,9 +4904,12 @@ static inline void util_est_update(struct cfs_rq *cfs_rq,
>          * quickly to settle down to our new util_avg.
>          */
>         if (!task_sleep) {
> -               ewma &= ~UTIL_AVG_UNCHANGED;
> -               ewma = approximate_util_avg(ewma, p->se.delta_exec / 1000);
> -               goto done;
> +               if (task_util(p) > task_util_dequeued(p)) {
> +                       ewma &= ~UTIL_AVG_UNCHANGED;
> +                       ewma = approximate_util_avg(ewma, p->se.delta_exec / 1000);

Same 32bit build issue due to 64bit division here. Need to rework w/ do_div().

thanks
-john