From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Stezenbach Subject: Re: How git affects kernel.org performance Date: Mon, 8 Jan 2007 14:41:47 +0100 Message-ID: <20070108134147.GB5291@linuxtv.org> References: <1166304080.13548.8.camel@nigel.suspend2.net> <459152B1.9040106@zytor.com> <1168140954.2153.1.camel@nigel.suspend2.net> <45A08269.4050504@zytor.com> <45A083F2.5000000@zytor.com> <20070107085526.GR24090@1wt.eu> <20070107011542.3496bc76.akpm@osdl.org> <20070108030555.GA7289@in.ibm.com> <20070108125819.GA32756@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Suparna Bhattacharya , Andrew Morton , Willy Tarreau , Linus Torvalds , "H. Peter Anvin" , git@vger.kernel.org, nigel@nigel.suspend2.net, "J.H." , Randy Dunlap , Pavel Machek , kernel list , webmaster@kernel.org, "linux-ext4@vger.kernel.org" X-From: git-owner@vger.kernel.org Mon Jan 08 15:08:20 2007 Return-path: Envelope-to: gcvg-git@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1H3vAg-0005ua-LX for gcvg-git@gmane.org; Mon, 08 Jan 2007 15:08:19 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161298AbXAHOIK (ORCPT ); Mon, 8 Jan 2007 09:08:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161309AbXAHOIK (ORCPT ); Mon, 8 Jan 2007 09:08:10 -0500 Received: from allen.werkleitz.de ([80.190.251.108]:45534 "EHLO allen.werkleitz.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161306AbXAHOII (ORCPT ); Mon, 8 Jan 2007 09:08:08 -0500 X-Greylist: delayed 1467 seconds by postgrey-1.27 at vger.kernel.org; Mon, 08 Jan 2007 09:08:07 EST Received: from p54bea826.dip0.t-ipconnect.de ([84.190.168.38] helo=void.local) by allen.werkleitz.de with esmtpsa (TLS-1.0:DHE_RSA_3DES_EDE_CBC_SHA1:24) (Exim 4.63) (envelope-from ) id 1H3ukx-0005Fs-9z; Mon, 08 Jan 2007 14:41:44 +0100 Received: from js by void.local with local (Exim 3.35 #1 (Debian)) id 1H3ul1-0001SV-00; Mon, 08 Jan 2007 14:41:47 +0100 To: Theodore Tso Content-Disposition: inline In-Reply-To: <20070108125819.GA32756@thunk.org> User-Agent: Mutt/1.5.13 (2006-08-11) X-SA-Exim-Connect-IP: 84.190.168.38 X-Spam-Checker-Version: SpamAssassin 3.1.7 (2006-10-05) on allen.werkleitz.de X-Spam-Level: X-Spam-Status: No, score=-3.8 required=4.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.1.7 X-SA-Exim-Version: 4.2.1 (built Sun, 03 Dec 2006 00:39:09 +0000) X-SA-Exim-Scanned: Yes (on allen.werkleitz.de) Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: On Mon, Jan 08, 2007 at 07:58:19AM -0500, Theodore Tso wrote: > > The fastest and probably most important thing to add is some readahead > smarts to directories --- both to the htree and non-htree cases. If > you're using some kind of b-tree structure, such as XFS does for > directories, preallocation doesn't help you much. Delayed allocation > can save you if your delayed allocator knows how to structure disk > blocks so that a btree-traversal is efficient, but I'm guessing the > biggest reason why we are losing is because we don't have sufficient > readahead. This also has the advantage that it will help without > needing to doing a backup/restore to improve layout. Would e2fsck -D help? What kind of optimization does it perform? Thanks, Johannes