Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965069AbWHUMkh (ORCPT ); Mon, 21 Aug 2006 08:40:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751123AbWHUMkh (ORCPT ); Mon, 21 Aug 2006 08:40:37 -0400 Received: from galaxy.agh.edu.pl ([149.156.96.9]:45492 "EHLO galaxy.agh.edu.pl") by vger.kernel.org with ESMTP id S1751860AbWHUMkg (ORCPT ); Mon, 21 Aug 2006 08:40:36 -0400 Message-ID: <44E9A9C0.6000405@agh.edu.pl> Date: Mon, 21 Aug 2006 14:40:32 +0200 From: Andrzej Szymanski User-Agent: Mozilla Thunderbird 1.0.7 (Windows/20050923) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Neil Brown CC: Miquel van Smoorenburg , linux-kernel@vger.kernel.org Subject: Re: Strange write starvation on 2.6.17 (and other) kernels References: <44E0A69C.5030103@agh.edu.pl> <17641.3304.948174.971955@cse.unsw.edu.au> In-Reply-To: <17641.3304.948174.971955@cse.unsw.edu.au> Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1129 Lines: 35 Neil Brown wrote: > On Thursday August 17, miquels@cistron.nl wrote: > > Can you report the contents of /proc/meminfo before, during, and after > the long pause? > I'm particularly interested in MemTotal, Dirty, and Writeback, but the > others are of interest too. > > Thanks, > NeilBrown I've prepared two logs, from different machines, the first one is on software RAID5 (4 ATA disks) with deadline scheduler, the second on a single ATA disk with CFQ scheduler. In the first case 10 writer threads are sufficient to give large delays, in the second case I've run an additional tar thread reading from the disk. The logs are here: http://galaxy.agh.edu.pl/~szymans/logs/ Each writer starts with: Writing 200 MB to stdout without fsync than reports each write() that lasts > 3s along with pid: 6582 - Delayed 4806 ms. And finishes with: Max write delay: 14968 ms. Andrzej. - 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/