From: Valentin Schneider <valentin.schneider@arm.com>
To: Qais Yousef <qais.yousef@arm.com>
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Quentin Perret <qperret@google.com>,
Pavan Kondeti <pkondeti@codeaurora.org>,
Rik van Riel <riel@surriel.com>
Subject: Re: [PATCH 0/8] sched/fair: misfit task load-balance tweaks
Date: Wed, 03 Feb 2021 18:43:23 +0000 [thread overview]
Message-ID: <jhjim792dro.mognet@arm.com> (raw)
In-Reply-To: <20210203151400.ommltjjyuok4yj5e@e107158-lin>
Hi Qais,
On 03/02/21 15:14, Qais Yousef wrote:
> On 01/28/21 18:31, Valentin Schneider wrote:
>> Hi folks,
>>
>> Here is this year's series of misfit changes. On the menu:
>>
>> o Patch 1 is an independent active balance cleanup
>> o Patch 2 adds some more sched_asym_cpucapacity static branches
>> o Patch 3 introduces yet another margin for capacity to capacity
>> comparisons
>> o Patches 4-6 build on top of patch 3 and change capacity comparisons
>> throughout misfit load balancing
>> o Patches 7-8 fix some extra misfit issues I've been seeing on "real"
>> workloads.
>>
>> IMO the somewhat controversial bit is patch 3, because it attempts to solve
>> margin issues by... Adding another margin. This does solve issues on
>> existing platforms (e.g. Pixel4), but we'll be back to square one the day
>> some "clever" folks spin a platform with two different CPU capacities less than
>> 5% apart.
>
> One more margin is a cause of apprehension to me. But in this case I think it
> is the appropriate thing to do now. I can't think of a scenario where this
> could hurt.
>
Thanks for having a look!
> Thanks
>
> --
> Qais Yousef
next prev parent reply other threads:[~2021-02-03 18:44 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-28 18:31 [PATCH 0/8] sched/fair: misfit task load-balance tweaks Valentin Schneider
2021-01-28 18:31 ` [PATCH 1/8] sched/fair: Clean up active balance nr_balance_failed trickery Valentin Schneider
2021-02-03 15:14 ` Qais Yousef
2021-02-03 18:42 ` Valentin Schneider
2021-02-04 15:05 ` Qais Yousef
2021-02-05 13:51 ` Vincent Guittot
2021-02-05 14:05 ` Valentin Schneider
2021-02-05 14:34 ` Vincent Guittot
2021-01-28 18:31 ` [PATCH 2/8] sched/fair: Add more sched_asym_cpucapacity static branch checks Valentin Schneider
2021-02-03 15:14 ` Qais Yousef
2021-02-09 8:42 ` Vincent Guittot
2021-01-28 18:31 ` [PATCH 3/8] sched/fair: Tweak misfit-related capacity checks Valentin Schneider
2021-02-03 15:15 ` Qais Yousef
2021-02-03 18:42 ` Valentin Schneider
2021-02-05 14:31 ` Vincent Guittot
2021-02-05 16:59 ` Valentin Schneider
2021-02-05 17:17 ` Vincent Guittot
2021-02-05 20:07 ` Valentin Schneider
2021-02-08 15:29 ` Vincent Guittot
2021-02-08 17:49 ` Valentin Schneider
2021-01-28 18:31 ` [PATCH 4/8] sched/fair: Use dst_cpu's capacity rather than group {min, max} capacity Valentin Schneider
2021-02-03 15:15 ` Qais Yousef
2021-01-28 18:31 ` [PATCH 5/8] sched/fair: Make check_misfit_status() only compare dynamic capacities Valentin Schneider
2021-02-03 15:15 ` Qais Yousef
2021-02-04 10:49 ` Dietmar Eggemann
2021-02-04 11:34 ` Valentin Schneider
2021-02-04 14:57 ` Dietmar Eggemann
2021-01-28 18:31 ` [PATCH 6/8] sched/fair: Filter out locally-unsolvable misfit imbalances Valentin Schneider
2021-02-03 15:16 ` Qais Yousef
2021-02-03 18:43 ` Valentin Schneider
2021-01-28 18:31 ` [PATCH 7/8] sched/fair: Attempt misfit active balance when migration_type != migrate_misfit Valentin Schneider
2021-02-03 15:16 ` Qais Yousef
2021-02-03 18:43 ` Valentin Schneider
2021-02-04 11:44 ` Dietmar Eggemann
2021-02-04 12:22 ` Valentin Schneider
2021-02-09 8:58 ` Vincent Guittot
2021-02-09 18:19 ` Valentin Schneider
2021-01-28 18:31 ` [PATCH 8/8] sched/fair: Relax task_hot() for misfit tasks Valentin Schneider
2021-02-03 15:17 ` Qais Yousef
2021-02-08 16:21 ` Vincent Guittot
2021-02-08 18:24 ` Valentin Schneider
2021-02-09 8:56 ` Vincent Guittot
2021-02-03 15:14 ` [PATCH 0/8] sched/fair: misfit task load-balance tweaks Qais Yousef
2021-02-03 18:43 ` Valentin Schneider [this message]
2021-02-04 12:03 ` Dietmar Eggemann
2021-02-04 12:36 ` Valentin Schneider
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