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From: Peter Zijlstra <peterz@infradead.org>
To: Mike Galbraith <efault@gmx.de>
Cc: Paul Turner <pjt@google.com>,
	Venkatesh Pallipadi <venki@google.com>,
	Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH] sched: Optimize cgroup pick_next_task_fair
Date: Sat, 11 Feb 2012 16:02:17 +0100	[thread overview]
Message-ID: <1328972537.11320.11.camel@laptop> (raw)
In-Reply-To: <1328943389.7340.29.camel@marge.simpson.net>

On Sat, 2012-02-11 at 07:56 +0100, Mike Galbraith wrote:
> On Sat, 2012-02-11 at 06:05 +0100, Peter Zijlstra wrote: 
> > Since commit 2f36825b1 ("sched: Next buddy hint on sleep and preempt
> > path") it is likely we pick a new task from the same cgroup, doing a put
> > and then set on all intermediate entities is a waste of time, so try to
> > avoid this.
> 
> Good idea, we need to lose some weight. 

I actually set out to do something else, but then ended up here.. weird
how that works ;-)

My initial idea was to try and get rid of the pick_next_entity()
downward walk by keeping that data up-to-date when we dequeue/enqueue.

That all got a tad convoluted, I'll have to try it again. Anyway, that
ended up needing to rework the put/set stuff, and that part wasn't as
bad.


  reply	other threads:[~2012-02-11 15:02 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-11  5:05 [RFC][PATCH] sched: Optimize cgroup pick_next_task_fair Peter Zijlstra
2012-02-11  6:56 ` Mike Galbraith
2012-02-11 15:02   ` Peter Zijlstra [this message]
2012-02-16 23:20 ` Peter Zijlstra
2012-02-16 23:28   ` Peter Zijlstra
2014-02-11 12:16 ` [tip:sched/core] sched/fair: Track cgroup depth tip-bot for Peter Zijlstra
2014-02-11 12:16 ` [tip:sched/core] sched: Push put_prev_task() into pick_next_task( ) tip-bot for Peter Zijlstra
2014-02-12  7:00   ` Kirill Tkhai
2014-02-12 11:43     ` Peter Zijlstra
2014-02-12 14:06     ` Peter Zijlstra
2014-02-12 14:24       ` Kirill Tkhai
2014-02-12 14:54         ` Peter Zijlstra
2014-02-11 12:16 ` [tip:sched/core] sched/fair: Clean up the __clear_buddies_*() functions tip-bot for Peter Zijlstra
2014-02-11 12:16 ` [tip:sched/core] sched/fair: Optimize cgroup pick_next_task_fair( ) tip-bot for Peter Zijlstra

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