On Fri, Jun 17, 2016 at 03:09:36PM +0200, Rafael J. Wysocki wrote:
> On Fri, Jun 17, 2016 at 10:40 AM, Jisheng Zhang <jszh...@marvell.com> wrote:
> > Dear all,
> >
> > On Fri, 17 Jun 2016 16:30:23 +0800 Jisheng Zhang wrote:
> >
> >> Dear all,
> >>
> >> I found one regression: In an idle system, wakeups/s (reported by powertop)
> >> is increased a lot, e.g on a intel snb 4 core platform, the wakeup event
> >> number is increased from 8 wakeups/s to 24 wakeup/s. bisect points to
> >> this commit. I could send detailed bisect log if it's wanted.
> >>
> >
> > more information maybe useful: after the commit, the top two wakeup source
> > are
> >
> > Process [rcu_sched]
> >
> > Timer tick_sched_timer
>
> And what was there before the commit?
>
> Granted, I'm not seeing this on my systems.
>
> Paul, Peter, any ideas about what may be going on here?
Looks to me like this commit moved some code from synchronize_rcu() to
synchronize_sched(). Assuming that this is a CONFIG_PREEMPT=y system,
might there have been a decrease in the wakeups from the rcu_preempt
kthread?
Thanx, Paul
