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Date: Tue, 17 Sep 2024 22:09:24 +0200
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Subject: Re: [RFC PATCH 11/16] sched/qos: Add rampup multiplier QoS
To: Qais Yousef <qyousef@layalina.io>, Ingo Molnar <mingo@kernel.org>,
 Peter Zijlstra <peterz@infradead.org>,
 Vincent Guittot <vincent.guittot@linaro.org>,
 "Rafael J. Wysocki" <rafael@kernel.org>,
 Viresh Kumar <viresh.kumar@linaro.org>
Cc: Juri Lelli <juri.lelli@redhat.com>, Steven Rostedt <rostedt@goodmis.org>,
 John Stultz <jstultz@google.com>, linux-pm@vger.kernel.org,
 linux-kernel@vger.kernel.org
References: <20240820163512.1096301-1-qyousef@layalina.io>
 <20240820163512.1096301-12-qyousef@layalina.io>
From: Dietmar Eggemann <dietmar.eggemann@arm.com>
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On 20/08/2024 18:35, Qais Yousef wrote:

[...]

> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 0c10e2afb52d..3d9794db58e1 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4906,7 +4906,7 @@ static inline void util_est_update(struct cfs_rq *cfs_rq,
>  	if (!task_sleep) {
>  		if (task_util(p) > task_util_dequeued(p)) {
>  			ewma &= ~UTIL_AVG_UNCHANGED;
> -			ewma = approximate_util_avg(ewma, p->se.delta_exec / 1000);
> +			ewma = approximate_util_avg(ewma, (p->se.delta_exec/1000) * p->sched_qos.rampup_multiplier);

Isn't this exactly the idea from UTIL_EST_FASTER?

faster_est_approx(delta * 2) ... double speed even w/o contention?
                          ^
[...]