From: Theodore Tso Subject: Re: How git affects kernel.org performance Date: Mon, 8 Jan 2007 08:56:22 -0500 Message-ID: <20070108135622.GD32756@thunk.org> References: <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> <20070108134147.GB5291@linuxtv.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" Return-path: Received: from thunk.org ([69.25.196.29]:58635 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751540AbXAHN5r (ORCPT ); Mon, 8 Jan 2007 08:57:47 -0500 To: Johannes Stezenbach Content-Disposition: inline In-Reply-To: <20070108134147.GB5291@linuxtv.org> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Mon, Jan 08, 2007 at 02:41:47PM +0100, Johannes Stezenbach wrote: > > Would e2fsck -D help? What kind of optimization > does it perform? It will help a little; e2fsck -D compresses the logical view of the directory, but it doesn't optimize the physical layout on disk at all, and of course, it won't help with the lack of readahead logic. It's possible to improve how e2fsck -D works, at the moment, it's not trying to make the directory be contiguous on disk. What it should probably do is to pull a list of all of the blocks used by the directory, sort them, and then try to see if it can improve on the list by allocating some new blocks that would make the directory more contiguous on disk. I suspect any improvements that would be seen by doing this would be second order effects at most, though. - Ted