Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757727AbXHER4x (ORCPT ); Sun, 5 Aug 2007 13:56:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752074AbXHER4p (ORCPT ); Sun, 5 Aug 2007 13:56:45 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:32917 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752026AbXHER4p (ORCPT ); Sun, 5 Aug 2007 13:56:45 -0400 Date: Sun, 5 Aug 2007 19:55:47 +0200 From: Ingo Molnar To: Theodore Tso , Alan Cox , Claudio Martins , Jeff Garzik , =?iso-8859-1?Q?J=F6rn?= Engel , Linus Torvalds , Peter Zijlstra , linux-mm@kvack.org, Linux Kernel Mailing List , miklos@szeredi.hu, akpm@linux-foundation.org, neilb@suse.de, dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com, nikita@clusterfs.com, trond.myklebust@fys.uio.no, yingchao.zhou@gmail.com, richard@rsk.demon.co.uk, david@lang.hm Subject: Re: [PATCH 00/23] per device dirty throttling -v8 Message-ID: <20070805175547.GC3244@elte.hu> References: <20070803123712.987126000@chello.nl> <46B4E161.9080100@garzik.org> <20070804224706.617500a0@the-village.bc.nu> <200708050051.40758.ctpm@ist.utl.pt> <20070805014926.400d0608@the-village.bc.nu> <20070805144645.GA28263@thunk.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070805144645.GA28263@thunk.org> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: 1.0 X-ELTE-SpamLevel: s X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=1.0 required=5.9 tests=BAYES_50 autolearn=no SpamAssassin version=3.0.3 1.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1208 Lines: 26 * Theodore Tso wrote: > If you are always reading from the same small set of files (i.e., a > database workload), then those inodes only get updated every 5 seconds > (the traditional/default metadata update sync time, as well as the > default ext3 journal update time), it's no big deal. Or if you are > running a mail server, most of the time the mail queue files are > getting updated anyway as you process them, and usually the mail is > delivered before 5 seconds is up anyway. > > So earlier, when Ingo characterized it as, "whenever you read from a > file, even one in memory cache.... do a write!", it's probably a bit > unfair. Traditional Unix systems simply had very different workload > characteristics than many modern dekstop systems today. yeah, i didnt mean to say that it is _always_ a big issue, but "only a small number of files are read" is a very, very small minority of even the database server world. Ingo - 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/