Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 16 Jan 2002 19:08:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 16 Jan 2002 19:08:23 -0500 Received: from duteinh.et.tudelft.nl ([130.161.42.1]:57099 "EHLO duteinh.et.tudelft.nl") by vger.kernel.org with ESMTP id ; Wed, 16 Jan 2002 19:08:10 -0500 Date: Thu, 17 Jan 2002 01:07:58 +0100 From: Erik Mouw To: Andrea Arcangeli Cc: linux-kernel@vger.kernel.org, Rik van Riel Subject: Re: Rik spreading bullshit about VM Message-ID: <20020117000758.GL10175@arthur.ubicom.tudelft.nl> In-Reply-To: <20020116200459.E835@athlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20020116200459.E835@athlon.random> User-Agent: Mutt/1.3.25i Organization: Eric Conspiracy Secret Labs X-Eric-Conspiracy: There is no conspiracy! Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 16, 2002 at 08:04:59PM +0100, Andrea Arcangeli wrote: > I read here: > > http://linux.html.it/articoli/rik_van_riel_ita1.htm [...] > This is total bullshit. If there's something where the -aa VM is good > are the DBMS, that was designed for it basically, very lightweight, > basically no VM overhead also under very heavy I/O. Sorry, but in my opinion Rik's rmap VM still beats your VM under IO load. My benchmark is very simple: import a kernel tree into a CVS tree that already contains about 470 other kernel trees. Both the import directory and the CVS root are on the same disk. With 2.4.17 the mp3 player stutters, I can't even read email or edit a couple of files with XEmacs at the same time. With 2.4.17-rmap-11a the mp3 player runs smoothly and email and XEmacs are usable again. Some time ago Linus made the important observation that we shouldn't tune the scheduler for SMP systems simply because 99.9% of the systems in the world running linux have a single CPU. IMHO an equally well observation would be that we shouldn't tune the VM for the 0.1% of the systems in this world that run large DMBSes. The 99.9% majority is much more important. Just my 0.02. Erik -- J.A.K. (Erik) Mouw, Information and Communication Theory Group, Faculty of Information Technology and Systems, Delft University of Technology, PO BOX 5031, 2600 GA Delft, The Netherlands Phone: +31-15-2783635 Fax: +31-15-2781843 Email: J.A.K.Mouw@its.tudelft.nl WWW: http://www-ict.its.tudelft.nl/~erik/ - 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/