From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [Bug #12208] uml is very slow on 2.6.28 host Date: Tue, 16 Dec 2008 07:56:01 +0100 Message-ID: <1229410561.14605.42.camel@twins> References: Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Miklos Szeredi Cc: rjw@sisk.pl, efault@gmx.de, mingo@elte.hu, linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org On Tue, 2008-12-16 at 01:49 +0100, Miklos Szeredi wrote: > On Sat, 13 Dec 2008, Rafael J. Wysocki wrote: > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12208 > > Subject : uml is very slow on 2.6.28 host > > Submitter : Miklos Szeredi > > Date : 2008-12-12 9:35 (2 days old) > > References : http://marc.info/?l=linux-kernel&m=122907463518593&w=4 > > I did a bisection, and this is the commit which is responsible: > > commit 464b75273f64be7c81fee975bd6ca9593df3427b > Author: Peter Zijlstra > Date: Fri Oct 24 11:06:15 2008 +0200 > > sched: re-instate vruntime based wakeup preemption > > The advantage is that vruntime based wakeup preemption has a better > conceptual model. Here wakeup_gran = 0 means: preempt when 'fair'. > Therefore wakeup_gran is the granularity of unfairness we allow in order > to make progress. > > Signed-off-by: Peter Zijlstra > Acked-by: Mike Galbraith > Signed-off-by: Ingo Molnar How's 27? That code basically makes .28 do what .27 did, we tried something else for a little while and that made stuff suck rocks.