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Subject: Re: [patch 1/4] Ignore stolen time in the softlockup watchdog
From: Daniel Walker <dwalker@mvista.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
       Andrew Morton <akpm@linux-foundation.org>,
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Date: Tue, 24 Apr 2007 14:01:14 -0700
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On Tue, 2007-04-24 at 22:59 +0200, Ingo Molnar wrote:
> * Daniel Walker <dwalker@mvista.com> wrote:
> 
> > On Tue, 2007-04-24 at 13:24 -0700, Jeremy Fitzhardinge wrote:
> > 
> > > And sched_clock's use of local_irq_save/restore appears to be absolutely
> > > correct, so I think it must be triggering a bug in either the self-tests
> > > or lockdep itself.
> > 
> > Why does sched_clock need to disable interrupts?
> 
> i concur. To me it appears not "absolutely correct" that someone 
> apparently added local_irq_save/restore to sched_clock(), but "absolute 
> madness". sched_clock() is _very_ performance-sensitive for the 
> scheduler, do not mess with it.

It looks like it's used in some sort of warp check, but only when
jiffies is used .. So I'm totally stumped why it's in there..

Daniel