Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932653AbXAJB5d (ORCPT ); Tue, 9 Jan 2007 20:57:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932658AbXAJB5c (ORCPT ); Tue, 9 Jan 2007 20:57:32 -0500 Received: from smtp.ustc.edu.cn ([202.38.64.16]:58521 "HELO ustc.edu.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S932653AbXAJB5b (ORCPT ); Tue, 9 Jan 2007 20:57:31 -0500 Message-ID: <368394226.19365@ustc.edu.cn> X-EYOUMAIL-SMTPAUTH: wfg@mail.ustc.edu.cn Date: Wed, 10 Jan 2007 09:57:39 +0800 From: Fengguang Wu To: Linus Torvalds Cc: Theodore Tso , Suparna Bhattacharya , Andrew Morton , Willy Tarreau , "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" Subject: Re: How git affects kernel.org performance Message-ID: <20070110015739.GA26978@mail.ustc.edu.cn> Mail-Followup-To: Linus Torvalds , Theodore Tso , Suparna Bhattacharya , Andrew Morton , Willy Tarreau , "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" References: <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> <368329554.17014@ustc.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-GPG-Fingerprint: 53D2 DDCE AB5C 8DC6 188B 1CB1 F766 DA34 8D8B 1C6D User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1282 Lines: 48 On Tue, Jan 09, 2007 at 08:23:32AM -0800, Linus Torvalds wrote: > > > On Tue, 9 Jan 2007, Fengguang Wu 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 > > > > Here's is a quick hack to practice the directory readahead idea. > > Comments are welcome, it's a freshman's work :) > > Well, I'd probably have done it differently, but more important is whether > this actually makes a difference performance-wise. Have you benchmarked it > at all? Yes, a trivial test shows a marginal improvement, on a minimal debian system: # find / | wc -l 13641 # time find / > /dev/null real 0m10.000s user 0m0.210s sys 0m4.370s # time find / > /dev/null real 0m9.890s user 0m0.160s sys 0m3.270s > Doing an > > echo 3 > /proc/sys/vm/drop_caches > > is your friend for testing things like this, to force cold-cache > behaviour.. Thanks, I'll work out numbers on large/concurrent dir accesses soon. Regards, Wu - 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/