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From: Valentin Schneider <valentin.schneider@arm.com>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	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>,
	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: Thu, 04 Feb 2021 12:36:02 +0000	[thread overview]
Message-ID: <jhj4kis2eod.mognet@arm.com> (raw)
In-Reply-To: <66efcfb1-d6ee-248a-e337-d690cda1bb5a@arm.com>

On 04/02/21 13:03, Dietmar Eggemann wrote:
> How did you verify the benefit of these changes?
>
> It's clear that you need a platform with capacity_orig diffs <20%
> between CPU types (like Pixel4 - SD855 (4x261, 3x871, 1x1024) or QC's
> RB5 platform - SD865 (4x284, 3x871, 1*1024)) but which
> benchmark/testcase did you use?

Benchmark is the usual culprit:

  https://lisa-linux-integrated-system-analysis.readthedocs.io/en/master/kernel_tests.html#lisa.tests.scheduler.misfit.StaggeredFinishes

This test spawns 1 CPU hog per CPU, and screams whenever a CPU of capacity
X is running a hog while another CPU of capacity Y > X has been idling for
"too long" (a few ms). IOW it makes sure upmigration happens in a timely
manner.

Some of the test platforms (Juno (4+2 big.LITTLE), HiKey960 (4+4
big.LITTLE)) show some improvements due to the last 2 patches.

As for systems with CPUs in the [819-1024] "deadzone", Ionela's been kindly
running said test on said RB5, and the upmigrations look just fine with the
patches applied.

      reply	other threads:[~2021-02-04 12:36 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-28 18:31 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
2021-02-04 12:03     ` Dietmar Eggemann
2021-02-04 12:36       ` Valentin Schneider [this message]

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