Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934570Ab3DSVr0 (ORCPT ); Fri, 19 Apr 2013 17:47:26 -0400 Received: from e32.co.us.ibm.com ([32.97.110.150]:56321 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933294Ab3DSVrZ (ORCPT ); Fri, 19 Apr 2013 17:47:25 -0400 Date: Fri, 19 Apr 2013 14:47:09 -0700 From: "Paul E. McKenney" To: Kevin Hilman 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 , Arjan van de Ven , Christoph Lameter Subject: Re: [PATCH documentation 1/2] nohz1: Add documentation. Message-ID: <20130419214709.GO3479@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130411160524.GA30384@linux.vnet.ibm.com> <1365696359-30958-1-git-send-email-paulmck@linux.vnet.ibm.com> <877gjyxmiq.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <877gjyxmiq.fsf@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13041921-5406-0000-0000-000007ACAEDE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1240 Lines: 37 On Fri, Apr 19, 2013 at 02:01:49PM -0700, Kevin Hilman wrote: > "Paul E. McKenney" 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 Added, thank you for the review and comments! Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/