Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754905AbXHNH76 (ORCPT ); Tue, 14 Aug 2007 03:59:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751526AbXHNH7m (ORCPT ); Tue, 14 Aug 2007 03:59:42 -0400 Received: from mail.daysofwonder.com ([213.186.49.53]:55908 "EHLO mail.daysofwonder.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751265AbXHNH7k (ORCPT ); Tue, 14 Aug 2007 03:59:40 -0400 Subject: Re: [PATCH 00/23] per device dirty throttling -v8 From: Brice Figureau To: Andi Kleen Cc: Stewart Smith , linux-kernel@vger.kernel.org In-Reply-To: <20070814022529.GA11322@one.firstfloor.org> References: <20070803123712.987126000@chello.nl> <20070804063217.GA25069@elte.hu> <1186389638.30448.29.camel@localhost.localdomain> <1187055897.18858.31.camel@localhost.localdomain> <20070814022529.GA11322@one.firstfloor.org> Content-Type: text/plain Date: Tue, 14 Aug 2007 09:59:35 +0200 Message-Id: <1187078375.11811.7.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1608 Lines: 38 On Tue, 2007-08-14 at 04:25 +0200, Andi Kleen wrote: > On Tue, Aug 14, 2007 at 11:44:56AM +1000, Stewart Smith wrote: > > > Since the database fits in RAM, the only kind of access Mysql is doing > > > is writing to the innodb log, the mysql binlog and finally to the innodb > > > database files. > > > There are certainly a whole lot of fsync'ing happening. > > > > yes. Keep in mind that the binlog grows in file size too... so this has > > to sync all the metadata as well (ick, i know). Back in the first days of my original bug report I moved the binlogs to another disk and it didn't change anything to my issue. On Tue, 2007-08-14 at 04:25 +0200, Andi Kleen wrote: > It might be an interesting experiment to see if it still happens > with the file system remounted as ext2. ext2 has a much more > benign fsync than ext3. Is it possible to perform a live remount of the fs on ext2 ? Beside that, the RAID card has a battery backed RAM in write-back mode, I was told that fsync don't really hurt in this case (moreover the fs is mounted in journal=writeback mode). I'll post soon blktrace files in the original bug report, this will show exactly what is the disk workload in the baseline case _and_ in the underload atypical case. Maybe that will help to shed some lights on the issue? Anyway, thanks, -- Brice Figureau - 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/