From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Kevin Hilman <khilman@linaro.org>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu, Borislav Petkov <bp@alien8.de>,
Arjan van de Ven <arjan@linux.intel.com>,
Christoph Lameter <cl@linux.com>
Subject: Re: [PATCH documentation 1/2] nohz1: Add documentation.
Date: Fri, 19 Apr 2013 14:47:09 -0700 [thread overview]
Message-ID: <20130419214709.GO3479@linux.vnet.ibm.com> (raw)
In-Reply-To: <877gjyxmiq.fsf@linaro.org>
On Fri, Apr 19, 2013 at 02:01:49PM -0700, Kevin Hilman wrote:
> "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> writes:
>
> > +KNOWN ISSUES
>
> [...]
>
> > +o Unless all CPUs are idle, at least one CPU must keep the
> > + scheduling-clock interrupt going in order to support accurate
> > + timekeeping.
>
> At least with the implementation I'm using (Frederic's 3.9-nohz1
> branch), at least one CPU is forced to stay out of dyntick-idle
> *always*, even if all CPUs are idle.
>
> IMO, this is important to list as a known issue since this will have
> its own power implications when the system is mostly idle.
Good point! I added the following at the end of the known issues:
o If there are adaptive-ticks CPUs, there will be at least one
CPU keeping the scheduling-clock interrupt going, even if all
CPUs are otherwise idle.
> Otherwise, document looks great.
>
> Reviewed-by: Kevin Hilman <khilman@linaro.org>
Added, thank you for the review and comments!
Thanx, Paul
next prev parent reply other threads:[~2013-04-19 21:47 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-11 16:05 [PATCH documentation 0/2] OS-jitter documentation Paul E. McKenney
2013-04-11 16:05 ` [PATCH documentation 1/2] nohz1: Add documentation Paul E. McKenney
2013-04-11 16:05 ` [PATCH documentation 2/2] kthread: Document ways of reducing OS jitter due to per-CPU kthreads Paul E. McKenney
2013-04-11 17:18 ` Randy Dunlap
2013-04-11 18:40 ` Paul E. McKenney
2013-04-11 20:09 ` Randy Dunlap
2013-04-11 21:00 ` Paul E. McKenney
2013-04-11 16:48 ` [PATCH documentation 1/2] nohz1: Add documentation Randy Dunlap
2013-04-11 17:09 ` Paul E. McKenney
2013-04-11 17:14 ` Arjan van de Ven
2013-04-11 18:27 ` Paul E. McKenney
2013-04-11 18:43 ` Dipankar Sarma
2013-04-11 19:14 ` Paul E. McKenney
2013-04-11 18:25 ` Borislav Petkov
2013-04-11 19:13 ` Paul E. McKenney
2013-04-11 20:19 ` Borislav Petkov
2013-04-11 21:01 ` Paul E. McKenney
2013-04-12 8:05 ` Peter Zijlstra
2013-04-12 17:54 ` Paul E. McKenney
2013-04-12 17:56 ` Arjan van de Ven
2013-04-12 20:39 ` Paul E. McKenney
2013-04-15 16:00 ` Christoph Lameter
2013-04-15 16:41 ` Arjan van de Ven
2013-04-15 16:53 ` Christoph Lameter
2013-04-15 17:21 ` Arjan van de Ven
2013-04-19 21:01 ` Kevin Hilman
2013-04-19 21:47 ` Paul E. McKenney [this message]
2013-04-27 13:26 ` Frederic Weisbecker
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