From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756211AbXKXW3X (ORCPT ); Sat, 24 Nov 2007 17:29:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752684AbXKXW3Q (ORCPT ); Sat, 24 Nov 2007 17:29:16 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.31.123]:51200 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752550AbXKXW3Q (ORCPT ); Sat, 24 Nov 2007 17:29:16 -0500 Date: Sat, 24 Nov 2007 23:29:41 +0100 From: Pavel Machek To: Thomas Gleixner Cc: Ingo Molnar , kernel list Subject: Re: nohz and strange sleep latencies Message-ID: <20071124222941.GA1544@elf.ucw.cz> References: <20071119203152.GA1772@elf.ucw.cz> <20071119205555.GA28696@elte.hu> <20071119211142.GA1857@elf.ucw.cz> <20071120085704.GA19950@elte.hu> <20071120105458.GA1597@elf.ucw.cz> <20071120205454.GD10008@elte.hu> <20071120225246.GA24380@elte.hu> <20071122185238.GA1821@elf.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu 2007-11-22 21:29:51, Thomas Gleixner wrote: > On Thu, 22 Nov 2007, Pavel Machek wrote: > > > but perhaps somehow we miss this fact and fail to turn off the lapic > > > clockevents drivers? > > > > Ok, I guess I'm lost. If I offline second CPU, I immediately get > > 1000Hz timer tick... is that expected? > > Hmm. No. I have no idea why this is happening. > > 34196 total events, 55.083 events/sec > echo 0 >/sys/devices/system/cpu/cpu1/online > 36073 total events, 54.679 events/sec Strange... > Just to make sure what we are hunting: Do you have the same problem > with an non-pavel-tainted 2.6.24-rc3 ? The effect described above disappeared from both clean and tainted-pavel trees...? But I have verified again that time sleep 0.01 is perfectly willing to sleep for 0.9second on untainted 2.6.24-rc3... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html