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 <miklos@xxxxxxxxxx> > > 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@xxxxxxxxx> > 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@xxxxxxxxx> > Acked-by: Mike Galbraith <efault@xxxxxx> > Signed-off-by: Ingo Molnar <mingo@xxxxxxx> If that commit is responsible, then it should also be very slow in pre 28 kernels, where the same exists. Hm, there's another possibility. Can you try echo NO_LAST_BUDDY > /sys/kernel/debug/sched_features? -Mike -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
