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From: Mike Galbraith <efault@gmx.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Paul Turner <pjt@google.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	Clark Williams <clark@redhat.com>,
	Andrew Theurer <habanero@us.ibm.com>
Subject: Re: [RFC] sched: The removal of idle_balance()
Date: Fri, 15 Feb 2013 08:26:12 +0100	[thread overview]
Message-ID: <1360913172.4736.20.camel@marge.simpson.net> (raw)
In-Reply-To: <1360908819.23152.97.camel@gandalf.local.home>

On Fri, 2013-02-15 at 01:13 -0500, Steven Rostedt wrote:

> Think about it some more, just because we go idle isn't enough reason to
> pull a runable task over. CPUs go idle all the time, and tasks are woken
> up all the time. There's no reason that we can't just wait for the sched
> tick to decide its time to do a bit of balancing. Sure, it would be nice
> if the idle CPU did the work. But I think that frame of mind was an
> incorrect notion from back in the early 2000s and does not apply to
> today's hardware, or perhaps it doesn't apply to the (relatively) new
> CFS scheduler. If you want aggressive scheduling, make the task rt, and
> it will do aggressive scheduling.

(the throttle is supposed to keep idle_balance() from doing severe
damage, that may want a peek/tweak)

Hackbench spreads itself with FORK/EXEC balancing, how does say a kbuild
do with no idle_balance()?

-Mike


  reply	other threads:[~2013-02-15  7:26 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-15  6:13 Steven Rostedt
2013-02-15  7:26 ` Mike Galbraith [this message]
2013-02-15 12:07   ` Peter Zijlstra
2013-02-15 12:21   ` Peter Zijlstra
2013-02-15 12:32     ` Mike Galbraith
2013-02-16 16:12   ` Steven Rostedt
2013-02-17  6:26     ` Mike Galbraith
2013-02-17  7:14       ` Mike Galbraith
2013-02-17 21:54         ` Steven Rostedt
2013-02-18  3:42           ` Mike Galbraith
2013-02-18 15:23             ` Steven Rostedt
2013-02-18 17:22               ` Mike Galbraith
2013-02-15  7:45 ` Joonsoo Kim
2013-02-15 15:05   ` Steven Rostedt
2013-02-17  6:26 ` Mike Galbraith
2013-02-18  8:13 ` Srikar Dronamraju
2013-02-18 15:25   ` Steven Rostedt
2013-02-19  4:13     ` Rakib Mullick
2013-02-19  7:29       ` Michael Wang

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