Re: [Bug #12208] uml is very slow on 2.6.28 host

Miklos Szeredi
2008-12-16T00:49:41Z

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 <miklos-sUDqSbJrdHQHWmgEVkV9KA@public.gmane.org>
> 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 <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>
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 <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>
Acked-by: Mike Galbraith <efault-Mmb7MZpHnFY@public.gmane.org>
Signed-off-by: Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>

Miklos