From: Frederic Weisbecker <fweisbec@gmail.com>
To: Don Zickus <dzickus@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Li Zhong <zhong@linux.vnet.ibm.com>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
Anish Singh <anish198519851985@gmail.com>
Subject: Re: [PATCH 4/6] watchdog: Boot-disable by default on full dynticks
Date: Thu, 13 Jun 2013 15:10:59 +0200 [thread overview]
Message-ID: <20130613131057.GA15997@somewhere> (raw)
In-Reply-To: <20130612170316.GO133453@redhat.com>
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.
Thanks.
next prev parent reply other threads:[~2013-06-13 13:11 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-12 14:02 [PATCH 0/6] timers nohz updates preview for 3.11 Frederic Weisbecker
2013-06-12 14:02 ` [PATCH 1/6] sched: Disable lb_bias feature for full dynticks Frederic Weisbecker
2013-06-12 14:02 ` [PATCH 2/6] nohz: Warn if the machine can not perform nohz_full Frederic Weisbecker
2013-06-12 14:02 ` [PATCH 3/6] watchdog: Register / unregister watchdog kthreads on sysctl control Frederic Weisbecker
2013-06-12 14:02 ` [PATCH 4/6] watchdog: Boot-disable by default on full dynticks Frederic Weisbecker
2013-06-12 17:03 ` Don Zickus
2013-06-13 13:10 ` Frederic Weisbecker [this message]
2013-06-13 14:02 ` Don Zickus
2013-06-13 14:22 ` Frederic Weisbecker
2013-06-13 14:45 ` Don Zickus
2013-06-13 14:56 ` Frederic Weisbecker
2013-06-13 15:20 ` Don Zickus
2013-06-13 15:48 ` Steven Rostedt
2013-06-13 16:21 ` anish singh
2013-06-13 17:16 ` Steven Rostedt
2013-06-14 4:17 ` anish singh
2013-06-14 12:26 ` Paul E. McKenney
2013-06-14 16:03 ` anish singh
2013-06-14 16:12 ` Steven Rostedt
2013-06-14 16:22 ` anish singh
2013-06-14 13:49 ` Don Zickus
2013-06-14 15:35 ` Steven Rostedt
2013-06-18 10:36 ` Peter Zijlstra
2013-06-18 12:04 ` Frederic Weisbecker
2013-06-18 12:53 ` Peter Zijlstra
2013-06-12 14:02 ` [PATCH 5/6] rcu: Prevent CPU from stopping tick if awaited for quiescent state report Frederic Weisbecker
2013-06-12 14:02 ` [PATCH 6/6] nohz: Remove obsolete check for full dynticks CPUs to be RCU nocbs Frederic Weisbecker
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