From mboxrd@z Thu Jan 1 00:00:00 1970 From: Damien Wyart Subject: Re: [Bug #12650] Strange load average and ksoftirqd behavior with 2.6.29-rc2-git1 Date: Mon, 16 Feb 2009 14:02:23 +0100 Message-ID: <87ljs6pmao.fsf@free.fr> References: <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> <20090216084223.GA2641@localhost.localdomain> <20090216095059.GL6182@elte.hu> <87hc2u61e9.fsf@free.fr> <20090216122632.GA3158@elte.hu> Mime-Version: 1.0 Return-path: Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Ingo Molnar Cc: "Paul E. McKenney" , Peter Zijlstra , Mike Galbraith , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List * Ingo Molnar [090216 13:26]: > We do get 0x100 which is 1 << RCU_SOFTIRQ, i.e. the RCU softirq. Paul, > this indeed seems to be a CONFIG_TREE_RCU=y bug. > What is weird is that RCU_SOFTIRQ gets set again and again - but there's > no raise_softirq() calls. Could you please do a two-CPU trace too via: > echo 3 > /debug/tracing/tracing_cpumask > So that we can see what's happening on the other CPU? > Also, could you please apply the debug patch below (or update to the > very latest -tip tree), so that we get trace entries of softirq triggers > too? Ok, the new trace with these additional modifications is here: http://damien.wyart.free.fr/ksoftirqd_pb/trace_tip_2009.02.16_1300_ksoftirqd_pb_abstime_proc_mask3.txt.gz -- Damien From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757736AbZBPNCe (ORCPT ); Mon, 16 Feb 2009 08:02:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755182AbZBPNCZ (ORCPT ); Mon, 16 Feb 2009 08:02:25 -0500 Received: from smtp-101-monday.noc.nerim.net ([62.4.17.101]:53645 "EHLO mallaury.nerim.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754954AbZBPNCZ (ORCPT ); Mon, 16 Feb 2009 08:02:25 -0500 From: Damien Wyart To: Ingo Molnar Cc: "Paul E. McKenney" , 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 References: <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> <20090216084223.GA2641@localhost.localdomain> <20090216095059.GL6182@elte.hu> <87hc2u61e9.fsf@free.fr> <20090216122632.GA3158@elte.hu> Date: Mon, 16 Feb 2009 14:02:23 +0100 Message-ID: <87ljs6pmao.fsf@free.fr> User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/23.0.90 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar [090216 13:26]: > We do get 0x100 which is 1 << RCU_SOFTIRQ, i.e. the RCU softirq. Paul, > this indeed seems to be a CONFIG_TREE_RCU=y bug. > What is weird is that RCU_SOFTIRQ gets set again and again - but there's > no raise_softirq() calls. Could you please do a two-CPU trace too via: > echo 3 > /debug/tracing/tracing_cpumask > So that we can see what's happening on the other CPU? > Also, could you please apply the debug patch below (or update to the > very latest -tip tree), so that we get trace entries of softirq triggers > too? Ok, the new trace with these additional modifications is here: http://damien.wyart.free.fr/ksoftirqd_pb/trace_tip_2009.02.16_1300_ksoftirqd_pb_abstime_proc_mask3.txt.gz -- Damien