From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753171Ab0ILPlm (ORCPT ); Sun, 12 Sep 2010 11:41:42 -0400 Received: from mail.lncsa.com ([213.215.28.11]:57466 "EHLO sargon.lncsa.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751960Ab0ILPlk (ORCPT ); Sun, 12 Sep 2010 11:41:40 -0400 Date: Sun, 12 Sep 2010 17:41:38 +0200 From: Louis-David Mitterrand To: linux-kernel@vger.kernel.org Subject: Re: ksoftirqd/n permanently eating 60% of a CPU Message-ID: <20100912154138.GA23554@apartia.fr> Mail-Followup-To: linux-kernel@vger.kernel.org References: <20100905173905.GA7387@apartia.fr> <20100912103130.GA21790@rhlx01.hs-esslingen.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100912103130.GA21790@rhlx01.hs-esslingen.de> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 12, 2010 at 12:31:30PM +0200, Andreas Mohr wrote: > Hi, > > Since there hasn't been a reply in a week, let me try to provide at > least a semi-useless one ;) Hi and thanks for offering your help. > Such high use probably means that something in the kernel keeps > retriggering some > tasklet(?) since it thinks that something hasn't been done yet > (i.e., the tasklet that got triggered didn't manage to satisfy the success > criteria of its owner), > or it means that something "legitimately" uses obscene amounts of > softirqd activity (perhaps some debug infrastructure such as memory tracing > or logging or some such). > > Thus: > 1. boot with "single" or "init=/bin/bash" kernel commandline and check > whether the activity still happens Booting 2.6.35.4 with init=/bin/bash doesn't fix the problem: ksoftirqd/n keeps firing at 50/60% CPU. No daemons are running of course. Examining /proc/interrupts shows that "Local timer interrupts" are mainly firing. Strangely enough, the interrupt storm starts only 5 minutes or so after bootup. I'd like to get to the bottom of this. As it happens on several, very different machines.