Re: [tip:sched/core] sched: Untangle cpu-load and timekeeping code

From: Peter Zijlstra
Date: Thu Jan 27 2011 - 05:09:14 EST


On Thu, 2011-01-27 at 15:13 +0800, Yong Zhang wrote:
> On Wed, Jan 26, 2011 at 8:14 PM, tip-bot for Peter Zijlstra
> <a.p.zijlstra@xxxxxxxxx> wrote:
> > Commit-ID: 18a57c3b43781ea83c3bb21c3add84ba890d5fb3
> > Gitweb: http://git.kernel.org/tip/18a57c3b43781ea83c3bb21c3add84ba890d5fb3
> > Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> > AuthorDate: Tue, 25 Jan 2011 11:30:35 +0100
> > Committer: Ingo Molnar <mingo@xxxxxxx>
> > CommitDate: Wed, 26 Jan 2011 12:33:23 +0100
> >
> > sched: Untangle cpu-load and timekeeping code
> >
> > Remove the calc_global_load() call from the timekeeping code and make
> > it local to the scheduler.
> >
> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> > LKML-Reference: <new-submission>
> > Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
>
> Now another question comes into my head:
>
> Previous we stop load calculation only when we goes to full idle,
> say every CPU goes to idle. tick_do_timer_cpu is jumping to
> the no-idle one so we can always get the real load.
>
> But now, if the CPU on which the global_load_timer resident
> goes to idle and there is still no-idle cpu in system, the load
> calculation stops. So it's not reflecting the real load after
> that.

Hmm, good point, Thomas is there any way we can make this timer stay on
an active cpu for as long as there is one?

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