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From: Valentin Schneider <valentin.schneider@arm.com>
To: Oliver Sang <oliver.sang@intel.com>
Cc: 0day robot <lkp@intel.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	LKML <linux-kernel@vger.kernel.org>,
	lkp@lists.01.org, ying.huang@intel.com, feng.tang@intel.com,
	zhengjun.xing@intel.com,
	Lingutla Chandrasekhar <clingutla@codeaurora.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Qais Yousef <qais.yousef@arm.com>,
	Quentin Perret <qperret@google.com>,
	Pavan Kondeti <pkondeti@codeaurora.org>,
	Rik van Riel <riel@surriel.com>,
	aubrey.li@linux.intel.com, yu.c.chen@intel.com
Subject: Re: [sched/fair]  38ac256d1c:  stress-ng.vm-segv.ops_per_sec -13.8% regression
Date: Thu, 22 Apr 2021 21:42:31 +0100	[thread overview]
Message-ID: <87mttqt5jc.mognet@arm.com> (raw)
In-Reply-To: <87wnsutzi9.mognet@arm.com>

On 22/04/21 10:55, Valentin Schneider wrote:
> I'll go find myself some other x86 box and dig into it;
> I'd rather not leave this hanging for too long.

So I found myself a dual-socket Xeon Gold 5120 @ 2.20GHz (64 CPUs) and
*there* I get a somewhat consistent ~-6% regression. As I'm suspecting
cacheline shenanigans, I also ran that with Peter's recent
kthread_is_per_cpu() change, and that brings it down to ~-3%

I'll leave it at here for today, but at least that's something I can work
with.

  reply	other threads:[~2021-04-22 20:42 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-07 22:06 [PATCH v5 0/3] sched/fair: load-balance vs capacity margins Valentin Schneider
2021-04-07 22:06 ` [PATCH v5 1/3] sched/fair: Ignore percpu threads for imbalance pulls Valentin Schneider
2021-04-09 11:24   ` [tip: sched/core] " tip-bot2 for Lingutla Chandrasekhar
2021-04-09 12:05   ` tip-bot2 for Lingutla Chandrasekhar
2021-04-09 16:14   ` tip-bot2 for Lingutla Chandrasekhar
2021-04-14  5:21   ` [sched/fair] 38ac256d1c: stress-ng.vm-segv.ops_per_sec -13.8% regression kernel test robot
2021-04-14 17:17     ` Valentin Schneider
2021-04-21  3:20       ` Oliver Sang
2021-04-21 10:27         ` Valentin Schneider
2021-04-21 12:03           ` Peter Zijlstra
2021-04-22  7:47           ` Oliver Sang
2021-04-22  9:55             ` Valentin Schneider
2021-04-22 20:42               ` Valentin Schneider [this message]
2021-04-28 22:00                 ` Valentin Schneider
2021-05-06 16:11                   ` Valentin Schneider
2021-04-07 22:06 ` [PATCH v5 2/3] sched/fair: Clean up active balance nr_balance_failed trickery Valentin Schneider
2021-04-09 11:24   ` [tip: sched/core] " tip-bot2 for Valentin Schneider
2021-04-09 12:05   ` tip-bot2 for Valentin Schneider
2021-04-09 16:14   ` tip-bot2 for Valentin Schneider
2021-04-07 22:06 ` [PATCH v5 3/3] sched/fair: Introduce a CPU capacity comparison helper Valentin Schneider
2021-04-09 11:24   ` [tip: sched/core] " tip-bot2 for Valentin Schneider
2021-04-09 12:05   ` tip-bot2 for Valentin Schneider
2021-04-09 16:14   ` tip-bot2 for Valentin Schneider

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