From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: [Bug 18632] "INFO: task" dpkg "blocked for more than 120 seconds. Date: Thu, 9 Jun 2011 20:43:15 +0800 Message-ID: <20110609124315.GA8789@localhost> References: <201106082138.p58Lchgj002615@demeter2.kernel.org> <20110608150241.8412a63d.akpm@linux-foundation.org> <20110609033217.GA10741@localhost> <20110609035426.GA12061@localhost> <20110609082718.GA10335@infradead.org> <20110609090906.GA19186@localhost> <20110609110214.GA9017@infradead.org> <20110609121117.GA5768@localhost> <20110609121742.GA29569@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dave Chinner , Andrew Morton , Jan Kara , "linux-fsdevel@vger.kernel.org" , "bugzilla-daemon@bugzilla.kernel.org" , "daaugusto@gmail.com" , "kernel-bugzilla@cygnusx-1.org" , "listposter@gmail.com" , "justincase@yopmail.com" , Tao Ma , Jens Axboe , Vivek Goyal To: Christoph Hellwig , Carlos Alberto Lopez Perez Return-path: Received: from mga02.intel.com ([134.134.136.20]:10519 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756873Ab1FIMnY (ORCPT ); Thu, 9 Jun 2011 08:43:24 -0400 Content-Disposition: inline In-Reply-To: <20110609121742.GA29569@infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: > > It's definitely a problem that cfq delays async writes too much. > > However in Carlos's report, > > > > https://bugzilla.kernel.org/attachment.cgi?id=61222 > > > > there are no sync(1) or fsync running at all. So it may be indicating > > a different problem. > > If you have a heavy read load we still need to write back timestamps, > and it kinda sounds like he's hitting that. No guarantee that actuall > is the cause, though. Right, in the other email I do find the reads. So Carlos, it's worthwhile to try the deadline scheduler, which will at least improve read/write workloads (likely the one you are running) that don't involve sync/fsync. Thanks, Fengguang