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" Return-path: To: Theodore Tso Content-Disposition: inline In-Reply-To: <20070108125819.GA32756@thunk.org> Sender: git-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org 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