Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754117Ab2B2Tt5 (ORCPT ); Wed, 29 Feb 2012 14:49:57 -0500 Received: from mga12.intel.com ([143.182.124.36]:5596 "EHLO azsmga102.ch.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753960Ab2B2Ttl convert rfc822-to-8bit (ORCPT ); Wed, 29 Feb 2012 14:49:41 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of dan.j.williams@intel.com designates 10.182.188.36 as permitted sender) smtp.mail=dan.j.williams@intel.com MIME-Version: 1.0 In-Reply-To: <1330507023.11248.113.camel@twins> References: <20120227203847.22153.62468.stgit@dwillia2-linux.jf.intel.com> <1330422535.11248.78.camel@twins> <1330507023.11248.113.camel@twins> Date: Wed, 29 Feb 2012 11:49:39 -0800 Message-ID: Subject: Re: [RFC PATCH] kick ksoftirqd more often to please soft lockup detector From: Dan Williams To: Peter Zijlstra Cc: Thomas Gleixner , linux-kernel@vger.kernel.org, Jens Axboe , linux-scsi@vger.kernel.org, Lukasz Dorau , James Bottomley , Andrzej Jakowski Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1512 Lines: 34 On Wed, Feb 29, 2012 at 1:17 AM, Peter Zijlstra wrote: > On Tue, 2012-02-28 at 14:16 -0800, Dan Williams wrote: >> Looks like everyone is guilty: >> >> [ ?422.765336] softirq took longer than 1/4 tick: 3 NET_RX ffffffff813f0aa0 >> ... >> [ ?423.971878] softirq took longer than 1/4 tick: 4 BLOCK ffffffff812519c8 >> [ ?423.985093] softirq took longer than 1/4 tick: 6 TASKLET ffffffff8103422e >> [ ?423.993157] softirq took longer than 1/4 tick: 7 SCHED ffffffff8105e2e1 >> [ ?424.001018] softirq took longer than 1/4 tick: 9 RCU ffffffff810a0fed >> [ ?424.008691] softirq loop took longer than 1/2 tick need_resched: > > /me kicks himself for not printing the actual duration.. :-) > >> As expected whenever that 1/2 tick message gets emitted the softirq >> handler is almost running in a need_resched() context. > > Yeah.. that's quite expected. > >> So is it a good idea to get more aggressive about scheduling ksoftrrqd? > > Nah, moving away from softirq more like. I'll put moving the > load-balancer into a kthread on the todo list. And it looks like > everybody else should move to kthreads too. I seem to recall this running into resistance (but maybe things have changed in the last few years)? https://lkml.org/lkml/2007/6/29/155 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/