From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756246AbZBPImi (ORCPT ); Mon, 16 Feb 2009 03:42:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754649AbZBPIma (ORCPT ); Mon, 16 Feb 2009 03:42:30 -0500 Received: from smtp-101-monday.noc.nerim.net ([62.4.17.101]:55461 "EHLO mallaury.nerim.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754531AbZBPIm3 (ORCPT ); Mon, 16 Feb 2009 03:42:29 -0500 Date: Mon, 16 Feb 2009 09:42:23 +0100 From: Damien Wyart To: Ingo Molnar Cc: Peter Zijlstra , Mike Galbraith , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List Subject: Re: [Bug #12650] Strange load average and ksoftirqd behavior with 2.6.29-rc2-git1 Message-ID: <20090216084223.GA2641@localhost.localdomain> References: <20090215080941.GA2295@localhost.localdomain> <20090215090026.GA31147@elte.hu> <20090215095128.GA3234@localhost.localdomain> <20090215101351.GA23274@elte.hu> <20090215103445.GA2335@localhost.localdomain> <20090215110104.GB31351@elte.hu> <20090215180355.GA2273@localhost.localdomain> <20090215193102.GA16873@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090215193102.GA16873@elte.hu> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Ok, I've redone the tests under tip from this morning (Paris time). Everything is in http://damien.wyart.free.fr/ksoftirqd_pb/ * Ingo Molnar [2009-02-15 20:31]: > Yes, an abstime trace would be useful. The corresponding file is trace_tip_2009.02.16_ksoftirqd_pb_abstime.txt.gz and there is also a trace without abstime: trace_tip_2009.02.16_ksoftirqd_pb.txt.gz > > checking TSC synchronization [CPU#0 -> CPU#1]: passed. > > Switched to high resolution mode on CPU 1 > Lets double-check your scheduler clock first. Without being able to > trust the clock we cannot trust the task stats nor the trace output. > What does this check display: > http://people.redhat.com/mingo/time-warp-test/time-warp-test.c The file is time-warp-test_result.txt I've let it run for a few tens of minutes; the first number varies slightly sometimes. The second one stays at 0. > Does it find any TSC time warps? Seems not. > Also, could you send the output of: > http://people.redhat.com/mingo/cfs-scheduler/tools/cfs-debug-info.sh > Run it while you can see the ksoftirqd anomaly. In fact I see it all the time when the machine is idle. When something runs (spamd for example), the running time of ksoftirqd stops increasing, and it goes back to increasing like crazy when idle state comes back. The corresponding file is cfs-debug-info-2009.02.16-08.09.17.gz Hope this will be useful; do not hesitate to ask for further info. Now that I have tip, I guess it will be easier. -- Damien