From: Rik van Riel <riel@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>, mingo@kernel.org
Cc: dedekind1@gmail.com, linux-kernel@vger.kernel.org,
mgorman@suse.de, rostedt@goodmis.org, juri.lelli@arm.com
Subject: Re: [RFC][PATCH 4/4] sched, numa: Ignore pinned tasks
Date: Fri, 15 May 2015 15:05:57 -0400 [thread overview]
Message-ID: <55564395.70406@redhat.com> (raw)
In-Reply-To: <20150515154833.726258767@infradead.org>
On 05/15/2015 11:43 AM, Peter Zijlstra wrote:
> Per cpu (kernel) threads can currently trick the load balancer in
> thinking there's something to do and result in moving perfectly placed
> tasks away.
>
> By virtue of the new do_set_cpus_allowed() we can easily add nr_pinned
> accounting. Which we'll use to change the fbq classification such that
> we make it less likely to pick such tasks for migration.
>
> Note that it is still possible we'll migrate these well placed tasks
> away, further patches could reduce this still.
A few ideas here :)
- Identify whether the current task on a CPU is the one
that would like to migrate, and treat the runqueue as
"movable" instead of "remote" if none of the runnable
but queued tasks want to migrate away.
- Teach can_migrate_task about the fbq types, and have
it enforce NUMA placement when the type is "remote",
and ignore NUMA placement when we know there are no
good tasks to move. This might require another
simplification of migrate_improves/degrades_locality.
> Suggested-by: Rik van Riel <riel@redhat.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
--
All rights reversed
next prev parent reply other threads:[~2015-05-15 19:06 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-15 15:43 [RFC][PATCH 0/4] sched,numa: pinned task accounting Peter Zijlstra
2015-05-15 15:43 ` [RFC][PATCH 1/4] sched: Fix a race between __kthread_bind() and sched_setaffinity() Peter Zijlstra
2015-05-15 15:56 ` Tejun Heo
2015-08-07 14:27 ` Peter Zijlstra
2015-08-07 15:16 ` Tejun Heo
2015-08-07 15:29 ` Peter Zijlstra
2015-08-07 15:38 ` Tejun Heo
2015-08-07 15:59 ` Peter Zijlstra
2015-08-07 16:09 ` Tejun Heo
2015-08-12 12:38 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2015-05-15 15:43 ` [RFC][PATCH 2/4] sched: Make sched_class::set_cpus_allowed() unconditional Peter Zijlstra
2015-08-12 12:38 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2015-08-20 16:45 ` [RFC][PATCH 2/4] " Sasha Levin
2015-05-15 15:43 ` [RFC][PATCH 3/4] sched: Change sched_class::set_cpus_allowed calling context Peter Zijlstra
[not found] ` <OF66BF3765.2EBFD3B1-ON48257E49.0028DC79-48257E49.0029F058@zte.com.cn>
2015-05-18 8:32 ` Peter Zijlstra
2015-05-18 9:34 ` Juri Lelli
2015-05-18 20:04 ` Peter Zijlstra
2015-08-12 12:38 ` [tip:sched/core] sched: Change the sched_class::set_cpus_allowed( ) " tip-bot for Peter Zijlstra
2015-08-13 18:47 ` Sasha Levin
2015-08-13 20:37 ` Peter Zijlstra
2015-08-13 20:59 ` Sasha Levin
2015-08-13 21:30 ` Peter Zijlstra
2015-05-15 15:43 ` [RFC][PATCH 4/4] sched, numa: Ignore pinned tasks Peter Zijlstra
2015-05-15 19:05 ` Rik van Riel [this message]
2015-05-16 9:31 ` Peter Zijlstra
2015-05-18 13:00 ` Srikar Dronamraju
2015-05-18 13:06 ` Peter Zijlstra
2015-05-18 14:13 ` Rik van Riel
2015-05-18 14:29 ` Srikar Dronamraju
2015-05-18 15:09 ` Peter Zijlstra
2015-05-18 13:10 ` Srikar Dronamraju
2015-05-18 9:08 ` [RFC][PATCH 0/4] sched,numa: pinned task accounting Artem Bityutskiy
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