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From: Mike Galbraith <efault@gmx.de>
To: Vincent Guittot <vincent.guittot@linaro.org>,
	mingo@redhat.com,  peterz@infradead.org, juri.lelli@redhat.com,
	dietmar.eggemann@arm.com,  rostedt@goodmis.org,
	bsegall@google.com, mgorman@suse.de, vschneid@redhat.com,
	 linux-kernel@vger.kernel.org
Cc: kprateek.nayak@amd.com, pauld@redhat.com, luis.machado@arm.com
Subject: Re: [PATCH 0/10 v2] sched/fair: Fix statistics with delayed dequeue
Date: Sun, 01 Dec 2024 14:30:05 +0100	[thread overview]
Message-ID: <227863d758551e75cd0807a5f1f31916d695205b.camel@gmx.de> (raw)
In-Reply-To: <20241129161756.3081386-1-vincent.guittot@linaro.org>

Greetings,

On Fri, 2024-11-29 at 17:17 +0100, Vincent Guittot wrote:
> Delayed dequeued feature keeps a sleeping sched_entitiy enqueued until its
> lag has elapsed. As a result, it stays also visible in the statistics that
> are used to balance the system and in particular the field h_nr_running.
>
> This serie fixes those metrics by creating a new h_nr_queued that tracks
> all queued tasks. It renames h_nr_running into h_nr_runnable and restores
> the behavior of h_nr_running i.e. tracking the number of fair tasks that
>  want to run.
>
> h_nr_runnable is used in several places to make decision on load balance:
>   - PELT runnable_avg
>   - deciding if a group is overloaded or has spare capacity
>   - numa stats
>   - reduced capacity management
>   - load balance between groups

I took the series for a spin in tip v6.12-10334-gb1b238fba309, but
runnable seems to have an off-by-one issue, causing it to wander ever
further south.

patches 1-3 applied.
  .h_nr_runnable                 : -3046
  .runnable_avg                  : 450189777126

full set applied.
  .h_nr_runnable                 : -5707
  .runnable_avg                  : 4391793519526

	-Mike

  parent reply	other threads:[~2024-12-01 13:30 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-29 16:17 Vincent Guittot
2024-11-29 16:17 ` [PATCH 01/10 v2] sched/eevdf: More PELT vs DELAYED_DEQUEUE Vincent Guittot
2024-11-29 16:17 ` [PATCH 02/10 v2] sched/fair: Rename h_nr_running into h_nr_queued Vincent Guittot
2024-11-29 16:17 ` [PATCH 03/10 v2] sched/fair: Add new cfs_rq.h_nr_runnable Vincent Guittot
2024-12-02  9:54   ` Peter Zijlstra
2024-12-02  9:57     ` Vincent Guittot
2024-11-29 16:17 ` [PATCH 04/10 v2] sched/fair: Removed unsued cfs_rq.h_nr_delayed Vincent Guittot
2024-11-29 16:17 ` [PATCH 05/10 v2] sched/fair: Rename cfs_rq.idle_h_nr_running into h_nr_idle Vincent Guittot
2024-11-29 16:17 ` [PATCH 06/10 v2] sched/fair: Remove unused cfs_rq.idle_nr_running Vincent Guittot
2024-11-29 16:17 ` [PATCH 07/10 v2] sched/fair: Rename cfs_rq.nr_running into nr_queued Vincent Guittot
2024-11-29 16:17 ` [PATCH 08/10 v2] sched/fair: Do not try to migrate delayed dequeue task Vincent Guittot
2024-11-29 16:17 ` [PATCH 09/10 v2] sched/fair: Fix sched_can_stop_tick() for fair tasks Vincent Guittot
2024-11-29 18:26   ` K Prateek Nayak
2024-12-02  9:18     ` Vincent Guittot
2024-11-29 16:17 ` [PATCH 10/10 v2] sched/fair: Fix variable declaration position Vincent Guittot
2024-11-29 18:30   ` K Prateek Nayak
2024-12-02  9:19     ` Vincent Guittot
2024-12-01 13:30 ` Mike Galbraith [this message]
2024-12-02  9:17   ` [PATCH 0/10 v2] sched/fair: Fix statistics with delayed dequeue Vincent Guittot
2024-12-02  9:23     ` Luis Machado
2024-12-02  9:59       ` Vincent Guittot
2024-12-02 13:52         ` Dietmar Eggemann
2024-12-02  9:58     ` K Prateek Nayak
2024-12-02 11:42       ` Vincent Guittot
2024-12-02 14:24         ` Vincent Guittot
2024-12-02 18:34     ` Mike Galbraith

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