From: Juri Lelli <juri.lelli@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@redhat.com, vincent.guittot@linaro.org,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, vschneid@redhat.com,
clm@meta.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 02/12] sched/deadline: Less agressive dl_server handling
Date: Wed, 2 Jul 2025 17:12:24 +0100 [thread overview]
Message-ID: <aGVaaJif1metVJpA@jlelli-thinkpadt14gen4.remote.csb> (raw)
In-Reply-To: <20250702121158.465086194@infradead.org>
Hi Peter,
On 02/07/25 13:49, Peter Zijlstra wrote:
> Chris reported that commit 5f6bd380c7bd ("sched/rt: Remove default
> bandwidth control") caused a significant dip in his favourite
> benchmark of the day. Simply disabling dl_server cured things.
>
> His workload hammers the 0->1, 1->0 transitions, and the
> dl_server_{start,stop}() overhead kills it -- fairly obviously a bad
> idea in hind sight and all that.
>
> Change things around to only disable the dl_server when there has not
> been a fair task around for a whole period. Since the default period
> is 1 second, this ensures the benchmark never trips this, overhead
> gone.
>
> Fixes: 557a6bfc662c ("sched/fair: Add trivial fair server")
> Reported-by: Chris Mason <clm@meta.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Link: https://lkml.kernel.org/r/20250520101727.507378961@infradead.org
> ---
This looks good to me.
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Thanks!
Juri
next prev parent reply other threads:[~2025-07-02 16:12 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-02 11:49 [PATCH v2 00/12] sched: Address schbench regression Peter Zijlstra
2025-07-02 11:49 ` [PATCH v2 01/12] sched/psi: Optimize psi_group_change() cpu_clock() usage Peter Zijlstra
2025-07-15 19:11 ` Chris Mason
2025-07-16 6:06 ` K Prateek Nayak
2025-07-16 6:53 ` Beata Michalska
2025-07-16 10:40 ` Peter Zijlstra
2025-07-16 14:54 ` Johannes Weiner
2025-07-16 16:27 ` Chris Mason
2025-07-23 4:16 ` Aithal, Srikanth
2025-07-25 5:13 ` K Prateek Nayak
2025-07-02 11:49 ` [PATCH v2 02/12] sched/deadline: Less agressive dl_server handling Peter Zijlstra
2025-07-02 16:12 ` Juri Lelli [this message]
2025-07-10 12:46 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2025-07-14 22:56 ` [PATCH v2 02/12] " Mel Gorman
2025-07-15 14:55 ` Chris Mason
2025-07-16 18:19 ` Mel Gorman
2025-07-30 9:34 ` Geert Uytterhoeven
2025-07-30 9:46 ` Juri Lelli
2025-07-30 10:05 ` Geert Uytterhoeven
2025-08-05 22:03 ` Chris Bainbridge
2025-08-05 23:04 ` Chris Bainbridge
2025-07-02 11:49 ` [PATCH v2 03/12] sched: Optimize ttwu() / select_task_rq() Peter Zijlstra
2025-07-10 16:47 ` Vincent Guittot
2025-07-14 22:59 ` Mel Gorman
2025-07-02 11:49 ` [PATCH v2 04/12] sched: Use lock guard in ttwu_runnable() Peter Zijlstra
2025-07-10 16:48 ` Vincent Guittot
2025-07-14 23:00 ` Mel Gorman
2025-07-02 11:49 ` [PATCH v2 05/12] sched: Add ttwu_queue controls Peter Zijlstra
2025-07-10 16:51 ` Vincent Guittot
2025-07-14 23:14 ` Mel Gorman
2025-07-02 11:49 ` [PATCH v2 06/12] sched: Introduce ttwu_do_migrate() Peter Zijlstra
2025-07-10 16:51 ` Vincent Guittot
2025-07-02 11:49 ` [PATCH v2 07/12] psi: Split psi_ttwu_dequeue() Peter Zijlstra
2025-07-17 23:59 ` Chris Mason
2025-07-18 18:02 ` Steven Rostedt
2025-07-02 11:49 ` [PATCH v2 08/12] sched: Re-arrange __ttwu_queue_wakelist() Peter Zijlstra
2025-07-02 11:49 ` [PATCH v2 09/12] sched: Clean up ttwu comments Peter Zijlstra
2025-07-02 11:49 ` [PATCH v2 10/12] sched: Use lock guard in sched_ttwu_pending() Peter Zijlstra
2025-07-10 16:51 ` Vincent Guittot
2025-07-02 11:49 ` [PATCH v2 11/12] sched: Change ttwu_runnable() vs sched_delayed Peter Zijlstra
2025-07-02 11:49 ` [PATCH v2 12/12] sched: Add ttwu_queue support for delayed tasks Peter Zijlstra
2025-07-03 16:00 ` Phil Auld
2025-07-03 16:47 ` Peter Zijlstra
2025-07-03 17:11 ` Phil Auld
2025-07-14 13:57 ` Phil Auld
2025-07-04 6:13 ` K Prateek Nayak
2025-07-04 7:59 ` Peter Zijlstra
2025-07-08 12:44 ` Dietmar Eggemann
2025-07-08 18:57 ` Peter Zijlstra
2025-07-08 21:02 ` Peter Zijlstra
2025-07-23 5:42 ` Shrikanth Hegde
2025-07-02 15:27 ` [PATCH v2 00/12] sched: Address schbench regression Chris Mason
2025-07-07 9:05 ` Shrikanth Hegde
2025-07-07 9:11 ` Peter Zijlstra
2025-07-07 9:38 ` Shrikanth Hegde
2025-07-16 13:46 ` Phil Auld
2025-07-17 17:25 ` Phil Auld
2025-07-07 18:19 ` Shrikanth Hegde
2025-07-08 19:02 ` Peter Zijlstra
2025-07-09 16:46 ` Shrikanth Hegde
2025-07-14 17:54 ` Shrikanth Hegde
2025-07-21 19:37 ` Shrikanth Hegde
2025-07-22 20:20 ` Chris Mason
2025-07-24 18:23 ` Chris Mason
2025-07-08 15:09 ` Chris Mason
2025-07-08 17:29 ` Shrikanth Hegde
2025-07-17 13:04 ` Beata Michalska
2025-07-17 16:57 ` Beata Michalska
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