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From: Morten Rasmussen <morten.rasmussen@arm.com>
To: Quentin Perret <quentin.perret@arm.com>
Cc: peterz@infradead.org, mingo@redhat.com,
	valentin.schneider@arm.com, dietmar.eggemann@arm.com,
	vincent.guittot@linaro.org, gaku.inami.xh@renesas.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCHv4 11/12] sched/core: Disable SD_ASYM_CPUCAPACITY for root_domains without asymmetry
Date: Fri, 20 Jul 2018 14:54:10 +0100	[thread overview]
Message-ID: <20180720135410.GD19287@e105550-lin.cambridge.arm.com> (raw)
In-Reply-To: <20180705150311.GE32579@e108498-lin.cambridge.arm.com>

On Thu, Jul 05, 2018 at 04:03:11PM +0100, Quentin Perret wrote:
> On Thursday 05 Jul 2018 at 15:13:49 (+0100), Morten Rasmussen wrote:
> > 3. Detecting the flag in generic kernel/sched/* code means that all
> > architectures will pay the for the overhead when building/rebuilding the
> > sched_domain hierarchy, and all architectures that sets the cpu
> > capacities to asymmetric will set the flag whether they like it or not.
> > I'm not sure if this is a problem.
> 
> That is true as well ...
> 
> > 
> > In the end it is really about how much of this we want in generic code
> > and how much we hide in arch/, and if we dare to touch the sched_domain
> > build code ;-)
> 
> Right so you can argue that the arch code is here to give you a
> system-level information, and that if the scheduler wants to virtually
> split that system, then it's its job to make sure that happens properly.
> That is exactly what your patch does (IIUC), and I now think that this
> is a very sensible middle-ground option. But this is debatable so I'm
> interested to see what others think :-)

I went ahead an hacked up some patches that sets the flag automatically
as part of the sched_domain build process. I posted them so people can
have a look: 1532093554-30504-1-git-send-email-morten.rasmussen@arm.com

With those patches this patch has to be reverted/dropped.

Morten

  reply	other threads:[~2018-07-20 13:54 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-04 10:17 [PATCHv4 00/12] sched/fair: Migrate 'misfit' tasks on asymmetric capacity systems Morten Rasmussen
2018-07-04 10:17 ` [PATCHv4 01/12] sched: Add static_key for asymmetric cpu capacity optimizations Morten Rasmussen
2018-07-31 10:59   ` Peter Zijlstra
2018-08-02 15:15     ` Morten Rasmussen
2018-09-10 10:13   ` [tip:sched/core] sched/topology: Add static_key for asymmetric CPU " tip-bot for Morten Rasmussen
2018-07-04 10:17 ` [PATCHv4 02/12] sched/fair: Add group_misfit_task load-balance type Morten Rasmussen
2018-09-10 10:13   ` [tip:sched/core] sched/fair: Add 'group_misfit_task' " tip-bot for Morten Rasmussen
2018-07-04 10:17 ` [PATCHv4 03/12] sched: Add sched_group per-cpu max capacity Morten Rasmussen
2018-09-10 10:14   ` [tip:sched/core] sched/fair: Add sched_group per-CPU " tip-bot for Morten Rasmussen
2018-07-04 10:17 ` [PATCHv4 04/12] sched/fair: Consider misfit tasks when load-balancing Morten Rasmussen
2018-09-10 10:14   ` [tip:sched/core] " tip-bot for Morten Rasmussen
2018-07-04 10:17 ` [PATCHv4 05/12] sched/fair: Kick nohz balance if rq->misfit_task_load Morten Rasmussen
2018-09-10 10:15   ` [tip:sched/core] " tip-bot for Valentin Schneider
2018-07-04 10:17 ` [PATCHv4 06/12] sched/fair: Change prefer_sibling type to bool Morten Rasmussen
2018-09-10 10:15   ` [tip:sched/core] sched/fair: Change 'prefer_sibling' " tip-bot for Valentin Schneider
2018-07-04 10:17 ` [PATCHv4 07/12] sched: Change root_domain->overload type to int Morten Rasmussen
2018-09-10 10:16   ` [tip:sched/core] sched/core: " tip-bot for Valentin Schneider
2018-07-04 10:17 ` [PATCHv4 08/12] sched: Wrap rq->rd->overload accesses with READ/WRITE_ONCE Morten Rasmussen
2018-09-10 10:17   ` [tip:sched/core] sched/fair: Wrap rq->rd->overload accesses with READ/WRITE_ONCE() tip-bot for Valentin Schneider
2018-07-04 10:17 ` [PATCHv4 09/12] sched/fair: Set rq->rd->overload when misfit Morten Rasmussen
2018-09-10 10:17   ` [tip:sched/core] " tip-bot for Valentin Schneider
2018-07-04 10:17 ` [PATCHv4 10/12] sched/fair: Don't move tasks to lower capacity cpus unless necessary Morten Rasmussen
2018-09-10 10:18   ` [tip:sched/core] sched/fair: Don't move tasks to lower capacity CPUs " tip-bot for Chris Redpath
2018-07-04 10:17 ` [PATCHv4 11/12] sched/core: Disable SD_ASYM_CPUCAPACITY for root_domains without asymmetry Morten Rasmussen
2018-07-05 13:31   ` Quentin Perret
2018-07-05 14:13     ` Morten Rasmussen
2018-07-05 15:03       ` Quentin Perret
2018-07-20 13:54         ` Morten Rasmussen [this message]
2018-07-04 10:17 ` [PATCHv4 12/12] sched/core: Disable SD_PREFER_SIBLING on asymmetric cpu capacity domains Morten Rasmussen
2018-07-06 10:18   ` Vincent Guittot
2018-07-06 14:31     ` Morten Rasmussen
2018-07-31 12:17       ` Vincent Guittot
2018-07-31 12:33         ` Valentin Schneider
2018-08-06 10:20           ` Vincent Guittot
2018-08-06 10:53             ` Valentin Schneider
2018-08-10  9:30               ` Vincent Guittot
2018-09-10 10:18   ` [tip:sched/core] sched/core: Disable SD_PREFER_SIBLING on asymmetric CPU " tip-bot for Morten Rasmussen
2018-07-06 10:18 ` [PATCHv4 00/12] sched/fair: Migrate 'misfit' tasks on asymmetric capacity systems Vincent Guittot
2018-07-09 15:08   ` Morten Rasmussen
2018-07-26 17:14     ` Valentin Schneider
2018-07-30 14:30       ` Dietmar Eggemann
2018-07-31 12:13         ` Vincent Guittot
2018-07-31 12:14           ` Dietmar Eggemann
2018-07-31 12:11     ` Vincent Guittot
2018-07-31 12:00 ` Peter Zijlstra
2018-07-31 12:10   ` Valentin Schneider
2018-07-31 12:50     ` Morten Rasmussen
2018-08-17  1:57 ` Joel Fernandes
2018-08-20  2:50 ` Gaku Inami

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