Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752792AbaA2R4X (ORCPT ); Wed, 29 Jan 2014 12:56:23 -0500 Received: from mail-vb0-f53.google.com ([209.85.212.53]:57369 "EHLO mail-vb0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752449AbaA2R4V (ORCPT ); Wed, 29 Jan 2014 12:56:21 -0500 MIME-Version: 1.0 In-Reply-To: <20140128175804.GA5287@netboy> References: <1389067023-13541-1-git-send-email-john.stultz@linaro.org> <20140113175114.GA4271@netboy> <52D42D36.1020400@linaro.org> <20140128175804.GA5287@netboy> Date: Wed, 29 Jan 2014 09:56:20 -0800 Message-ID: Subject: Re: [PATCH] [RFC] timekeeping: Rework frequency adjustments to work better w/ nohz From: John Stultz To: Richard Cochran Cc: LKML , Miroslav Lichvar , Prarit Bhargava Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 28, 2014 at 9:58 AM, Richard Cochran wrote: > I tested for a regression using the patched kernel with the nohz=off > command line option... > > On Mon, Jan 13, 2014 at 10:15:18AM -0800, John Stultz wrote: >> On 01/13/2014 09:51 AM, Richard Cochran wrote: >> > >> > - Linux 3.12.7-nohz-plain-20140106 nohz-plain.log >> > - Linux 3.12.7-nohz-plain-20140106 NOHZ=OFF periodic-plain.log >> > - Linux 3.12.7-nohz-fix-20140106-00001-gd753140 nohz-fix.log > > Regression check: > > - Linux homeboy 3.12.7-nohz-fix-20140106-00001-gd753140 NOHZ=OFF > nohz-fix-periodic.log > >> > The performance in the log files as reflected in the clock offset is >> > summarized in this table. The values are in nanoseconds. >> > >> > | | periodic-plain | nohz-fix | nohz-plain | >> > |---------+----------------+---------------+---------------| >> > | minimum | -1.599000e+03 | -1.051000e+03 | -5.373700e+04 | >> > | maximum | +1.311000e+03 | +1.048000e+03 | +6.389500e+04 | >> > | mean | +9.880240e-02 | -7.747305e+01 | +1.597904e+01 | >> > | stddev | +4.610021e+02 | +3.960978e+02 | +1.491263e+04 | > > Comparing the nohz=off case with and without the patch, the three hour > test looks like this. > > | | periodic-plain | nohz-fix-periodic | > |---------+----------------+-------------------+ > | minimum | -1.599000e+03 | -1.427000e+03 | > | maximum | +1.311000e+03 | +1.279000e+03 | > | mean | +9.880240e-02 | -2.710778e+01 | > | stddev | +4.610021e+02 | +3.974372e+02 | > >> > http://linuxptp.sourceforge.net/nohz-fix/current_nohz.png >> > http://linuxptp.sourceforge.net/nohz-fix/periodic_vs_fix.png > > I also made a third graph showing before and after the patch. > > http://linuxptp.sourceforge.net/nohz-fix/nohz_regression.png > >> If you do get a chance to look again, I'd also be interested if running >> with nohz=off w/ the fix doesn't show any regression compared to the >> unmodified nohz=off case. > > Looks like there is no regression. That's great to hear! Looks like we might be able to queue it for 3.15... Thanks so much again for the detailed testing! I really appreciate it! thanks -john -- 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/