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From: Morten Rasmussen <morten.rasmussen@arm.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	"mingo@redhat.com" <mingo@redhat.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Yuyang Du <yuyang.du@intel.com>,
	mgalbraith@suse.de, linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 07/13] sched/fair: Let asymmetric cpu configurations balance at wake-up
Date: Fri, 15 Jul 2016 09:37:33 +0100	[thread overview]
Message-ID: <20160715083732.GE21816@e105550-lin.cambridge.arm.com> (raw)
In-Reply-To: <CAKfTPtDE1NsA_q4zGrwBXBBHfdzjFwzPohO+iLqeooZ0S8-jQQ@mail.gmail.com>

On Thu, Jul 14, 2016 at 03:45:17PM +0200, Vincent Guittot wrote:
> On 13 July 2016 at 18:14, Morten Rasmussen <morten.rasmussen@arm.com> wrote:
> > On Wed, Jul 13, 2016 at 02:56:41PM +0200, Vincent Guittot wrote:
> >> On 22 June 2016 at 19:03, Morten Rasmussen <morten.rasmussen@arm.com> wrote:
> >> > Currently, SD_WAKE_AFFINE always takes priority over wakeup balancing if
> >> > SD_BALANCE_WAKE is set on the sched_domains. For asymmetric
> >> > configurations SD_WAKE_AFFINE is only desirable if the waking task's
> >> > compute demand (utilization) is suitable for all the cpu capacities
> >> > available within the SD_WAKE_AFFINE sched_domain. If not, let wakeup
> >>
> >> instead of "suitable for all the cpu capacities available within the
> >> SD_WAKE_AFFINE sched_domain", should it be "suitable for local cpu and
> >> prev cpu" becasue you only check the capacity of these 2 CPUs.
> >
> > Good point. I currently make the implicit assumption that capacity of local cpu
> > and prev cpu represent the capacity for all cpus their SD_WAKE_AFFINE
> > domains. It breaks if you should choose to have SD_WAKE_AFFINE on a
> > domain that spans both little and big cpus, as if local/prev cpu happens
> > to be big we assume that they are all big and let select_idle_sibling()
> > handle the task placement even for big tasks if local/prev cpu are both
> > big.
> 
> Isn't the sd_llc used in select_idle_sibling and not the
> SD_WAKE_AFFINE domian so if CPUs in the sd_llc are homogeneous, we are
> safe

Yes, I confused myself (again) with SD_WAKE_AFFINE and sd_llc in the
above. It should have been sd_llc instead of SD_WAKE_AFFINE. I will fix
the commit message to be correct.

  reply	other threads:[~2016-07-15  8:35 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-22 17:03 [PATCH v2 00/13] sched: Clean-ups and asymmetric cpu capacity support Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 01/13] sched: Fix power to capacity renaming in comment Morten Rasmussen
2016-08-10 18:03   ` [tip:sched/core] sched/core: " tip-bot for Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 02/13] sched/fair: Consistent use of prev_cpu in wakeup path Morten Rasmussen
2016-06-22 18:04   ` Rik van Riel
2016-06-23  9:56     ` Morten Rasmussen
2016-06-23 12:24       ` Rik van Riel
2016-08-10 18:03   ` [tip:sched/core] sched/fair: Make the use of prev_cpu consistent in the " tip-bot for Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 03/13] sched/fair: Optimize find_idlest_cpu() when there is no choice Morten Rasmussen
2016-07-13 12:20   ` Vincent Guittot
2016-08-10 18:03   ` [tip:sched/core] " tip-bot for Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 04/13] sched: Introduce SD_ASYM_CPUCAPACITY sched_domain topology flag Morten Rasmussen
2016-07-11  9:55   ` Peter Zijlstra
2016-07-11 10:42     ` Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 05/13] sched: Enable SD_BALANCE_WAKE for asymmetric capacity systems Morten Rasmussen
2016-07-11 10:04   ` Peter Zijlstra
2016-07-11 10:37     ` Morten Rasmussen
2016-07-11 11:04       ` Morten Rasmussen
2016-07-11 11:24         ` Peter Zijlstra
2016-07-12 14:26           ` Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 06/13] sched: Store maximum per-cpu capacity in root domain Morten Rasmussen
2016-07-11 10:18   ` Peter Zijlstra
2016-07-11 16:16     ` Dietmar Eggemann
2016-07-12 11:42       ` Peter Zijlstra
2016-07-13 11:18         ` Dietmar Eggemann
2016-07-13 12:40   ` Vincent Guittot
2016-07-13 13:48     ` Dietmar Eggemann
2016-07-13 16:37       ` Morten Rasmussen
2016-07-14 13:25         ` Vincent Guittot
2016-07-14 15:15           ` Morten Rasmussen
2016-07-15 11:46             ` Morten Rasmussen
2016-07-15 13:39               ` Vincent Guittot
2016-07-15 16:02                 ` Morten Rasmussen
2016-07-18 12:48                   ` Vincent Guittot
2016-07-18 15:11                     ` Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 07/13] sched/fair: Let asymmetric cpu configurations balance at wake-up Morten Rasmussen
2016-07-11 11:13   ` Peter Zijlstra
2016-07-11 12:32     ` Morten Rasmussen
2016-07-13 12:56   ` Vincent Guittot
2016-07-13 16:14     ` Morten Rasmussen
2016-07-14 13:45       ` Vincent Guittot
2016-07-15  8:37         ` Morten Rasmussen [this message]
2016-06-22 17:03 ` [PATCH v2 08/13] sched/fair: Compute task/cpu utilization at wake-up more correctly Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 09/13] sched/fair: Consider spare capacity in find_idlest_group() Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 10/13] sched: Add per-cpu max capacity to sched_group_capacity Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 11/13] sched/fair: Avoid pulling tasks from non-overloaded higher capacity groups Morten Rasmussen
2016-06-23 21:20   ` Sai Gurrappadi
2016-06-30  7:49     ` Morten Rasmussen
2016-07-14 16:39       ` Sai Gurrappadi
2016-07-15  8:39         ` Morten Rasmussen
2016-07-12 12:59   ` Peter Zijlstra
2016-07-12 14:34     ` Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 12/13] arm: Set SD_ASYM_CPUCAPACITY for big.LITTLE platforms Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 13/13] arm: Update arch_scale_cpu_capacity() to reflect change to define Morten Rasmussen
2016-06-28 10:20 ` [PATCH v2 00/13] sched: Clean-ups and asymmetric cpu capacity support Koan-Sin Tan
2016-06-30  7:53   ` Morten Rasmussen
2016-07-08  7:35 ` KEITA KOBAYASHI
2016-07-08  8:18   ` Morten Rasmussen
2016-07-11  8:33 ` Morten Rasmussen
2016-07-11 12:44   ` Vincent Guittot
2016-07-12 13:25   ` Peter Zijlstra
2016-07-12 14:39     ` Morten Rasmussen
2016-07-13 12:06 ` Vincent Guittot
2016-07-13 15:54   ` Morten Rasmussen

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