Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752808Ab3GBF6x (ORCPT ); Tue, 2 Jul 2013 01:58:53 -0400 Received: from e35.co.us.ibm.com ([32.97.110.153]:42300 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750857Ab3GBF6w (ORCPT ); Tue, 2 Jul 2013 01:58:52 -0400 Date: Mon, 1 Jul 2013 22:58:39 -0700 From: "Paul E. McKenney" To: Mike Galbraith Cc: Josh Triplett , linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu Subject: Re: [PATCH RFC nohz_full v2 2/7] nohz_full: Add rcu_dyntick data for scalable detection of all-idle state Message-ID: <20130702055839.GZ3773@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130628200949.GA17458@linux.vnet.ibm.com> <1372450222-19420-1-git-send-email-paulmck@linux.vnet.ibm.com> <1372450222-19420-2-git-send-email-paulmck@linux.vnet.ibm.com> <20130701153150.GB2923@leaf> <20130701155220.GL3773@linux.vnet.ibm.com> <20130701181601.GA7964@jtriplet-mobl1> <20130701182326.GQ3773@linux.vnet.ibm.com> <20130701183412.GA18804@jtriplet-mobl1> <20130701191656.GR3773@linux.vnet.ibm.com> <1372741852.7363.110.camel@marge.simpson.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1372741852.7363.110.camel@marge.simpson.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13070205-4834-0000-0000-0000089C13C1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 992 Lines: 27 On Tue, Jul 02, 2013 at 07:10:52AM +0200, Mike Galbraith wrote: > On Mon, 2013-07-01 at 12:16 -0700, Paul E. McKenney wrote: > > On Mon, Jul 01, 2013 at 11:34:13AM -0700, Josh Triplett wrote: > > > > > > This also naturally raises the question "How can we let userspace get > > > > > accurate time without forcing a timer tick?". > > > > > > > > We don't. ;-) > > > > > > We don't currently, hence my question about how we can. :) > > > > Per-CPU atomic clocks? > > Great idea, who needs timekeeping code. > > http://www.euronews.com/2013/04/02/swiss-sets-sights-on-miniscule-atomic-clock/ "in theory you’ll only need to set it once every 3,000 years, providing of course your battery lasts that long" ;-) ;-) ;-) 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/