From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756486Ab1HXFw2 (ORCPT ); Wed, 24 Aug 2011 01:52:28 -0400 Received: from mtagate2.uk.ibm.com ([194.196.100.162]:51460 "EHLO mtagate2.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756308Ab1HXFwZ (ORCPT ); Wed, 24 Aug 2011 01:52:25 -0400 Date: Wed, 24 Aug 2011 07:52:16 +0200 From: Heiko Carstens To: Stephen Boyd Cc: Joe Perches , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH] nohz: remove "Switched to NOHz mode" debugging messages Message-ID: <20110824055216.GA2511@osiris.boeblingen.de.ibm.com> References: <20110823112046.GB2540@osiris.boeblingen.de.ibm.com> <1314126777.1659.2.camel@Joe-Laptop> <4E53FC67.7090108@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E53FC67.7090108@codeaurora.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 23, 2011 at 12:15:51PM -0700, Stephen Boyd wrote: > On 08/23/2011 12:12 PM, Joe Perches wrote: > > On Tue, 2011-08-23 at 13:20 +0200, Heiko Carstens wrote: > >> From: Heiko Carstens > >> > >> When performing cpu hotplug tests the kernel printk log buffer gets flooded > >> with pointless "Switched to NOHz mode..." messages. Especially when afterwards > >> analyzing a dump this might have removed more interesting stuff out of the > >> buffer. > >> Assuming that switching to NOHz mode simply works just remove the printk. > >> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > > [] > >> - > >> - printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n", smp_processor_id()); > > Though I don't know if these are actually particularly > > useful messages, perhaps pr_info_ratelimited() might > > be appropriate instead. > > Or perhaps a printk_once() would be good. Presumably the second switch > to NOHz mode wouldn't be as dangerous as the first. Let's just remove them.