Re: [PATCH 4/6] watchdog: Boot-disable by default on full dynticks

From: Frederic Weisbecker
Date: Thu Jun 13 2013 - 09:11:11 EST

On Wed, Jun 12, 2013 at 01:03:16PM -0400, Don Zickus wrote:
> On Wed, Jun 12, 2013 at 04:02:36PM +0200, Frederic Weisbecker wrote:
> > When the watchdog runs, it prevents the full dynticks
> > CPUs from stopping their tick because the hard lockup
> > detector uses perf events internally, which in turn
> > rely on the periodic tick.
> >
> > Since this is a rather confusing behaviour that is not
> > easy to track down and identify for those who want to
> > test CONFIG_NO_HZ_FULL, let's default disable the
> > watchdog on boot time when full dynticks is enabled.
> >
> > The user can still enable it later on runtime using
> > proc or sysctl.
> I thought we had a conversation awhile ago, where we agreed this was going
> to be fixed for 3.11? Didn't Peter find the patch and apply it to his
> tree? I am confused why this is still needed?

We agreed on the patch but it hasn't been applied yet. I'm trying to get
a sane series of nohz patches before sending to Ingo.

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