Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755776AbZGMMwl (ORCPT ); Mon, 13 Jul 2009 08:52:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755542AbZGMMwl (ORCPT ); Mon, 13 Jul 2009 08:52:41 -0400 Received: from mga14.intel.com ([143.182.124.37]:26841 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755461AbZGMMwk (ORCPT ); Mon, 13 Jul 2009 08:52:40 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.42,390,1243839600"; d="scan'208";a="164360573" Date: Mon, 13 Jul 2009 20:52:08 +0800 From: Wu Fengguang To: Ronald Moesbergen Cc: Vladislav Bolkhovitin , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "kosaki.motohiro@jp.fujitsu.com" , "Alan.Brunelle@hp.com" , "hifumi.hisashi@oss.ntt.co.jp" , "linux-fsdevel@vger.kernel.org" , "jens.axboe@oracle.com" , "randy.dunlap@oracle.com" , Bart Van Assche Subject: Re: [RESEND] [PATCH] readahead:add blk_run_backing_dev Message-ID: <20090713125208.GA1629@localhost> References: <4A5395FD.2040507@vlnb.net> <4A5493A8.2000806@vlnb.net> <4A56FF32.2060303@vlnb.net> <4A570981.5080803@vlnb.net> <20090713123621.GA31051@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2082 Lines: 55 On Mon, Jul 13, 2009 at 08:47:31PM +0800, Ronald Moesbergen wrote: > 2009/7/13 Wu Fengguang : > > On Mon, Jul 13, 2009 at 08:12:14PM +0800, Ronald Moesbergen wrote: > >> 2009/7/10 Vladislav Bolkhovitin : > >> > > >> > Vladislav Bolkhovitin, on 07/10/2009 12:43 PM wrote: > >> >> > >> >> Ronald Moesbergen, on 07/10/2009 10:32 AM wrote: > >> >>>> > >> >>>> I've also long ago noticed that reading data from block devices is > >> >>>> slower > >> >>>> than from files from mounted on those block devices file systems. Can > >> >>>> anybody explain it? > >> >>>> > >> >>>> Looks like this is strangeness #2 which we uncovered in our tests (the > >> >>>> first > >> >>>> one was earlier in this thread why the context RA doesn't work with > >> >>>> cooperative I/O threads as good as it should). > >> >>>> > >> >>>> Can you rerun the same 11 tests over a file on the file system, please? > >> >>> > >> >>> I'll see what I can do. Just te be sure: you want me to run > >> >>> blockdev-perftest on a file on the OCFS2 filesystem which is mounted > >> >>> on the client over iScsi, right? > >> >> > >> >> Yes, please. > >> > > >> > Forgot to mention that you should also configure your backend storage as a > >> > big file on a file system (preferably, XFS) too, not as direct device, like > >> > /dev/vg/db-master. > >> > >> Ok, here are the results: > > > > Ronald, thanks for the numbers! > > You're welcome. > > >> client kernel: 2.6.26-15lenny3 (debian) > >> server kernel: 2.6.29.5 with readahead patch > > > > Do you mean the context readahead patch? > > No, I meant the blk_run_backing_dev patch. The patchnames are > confusing, I'll be sure to clarify them from now on. That's OK. I did see previous benchmarks were not helped by context readahead noticeably on CFQ, hehe. Thanks, Fengguang -- 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/