Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 7 Mar 2001 02:58:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 7 Mar 2001 02:58:45 -0500 Received: from www.wen-online.de ([212.223.88.39]:19216 "EHLO wen-online.de") by vger.kernel.org with ESMTP id ; Wed, 7 Mar 2001 02:58:33 -0500 Date: Wed, 7 Mar 2001 08:57:35 +0100 (CET) From: Mike Galbraith X-X-Sender: To: Marcelo Tosatti cc: Rik van Riel , linux-kernel , Alan Cox Subject: Re: [patch][rfc][rft] vm throughput 2.4.2-ac4 In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 6 Mar 2001, Marcelo Tosatti wrote: > On Fri, 2 Mar 2001, Mike Galbraith wrote: > > > On Thu, 1 Mar 2001, Rik van Riel wrote: > > > > > > > The merging at the elevator level only works if the requests sent to > > > > > it are right next to each other on disk. This means that randomly > > > > > sending stuff to disk really DOES DESTROY PERFORMANCE and there's > > > > > nothing the elevator could ever hope to do about that. > > > > > > > > True to some (very real) extent because of the limited buffering > > > > of requests. However, I can not find any useful information > > > > that the vm is using to guarantee the IT does not destroy > > > > performance by your own definition. > > > > > > Indeed. IMHO we should fix this by putting explicit IO > > > clustering in the ->writepage() functions. > > > > I notice there's a patch sitting in my mailbox.. think I'll go read > > it and think (grunt grunt;) about this issue some more. > > Mike, > > One important information which is not being considered by > page_launder() now the dirty buffers watermark. > > In general, it should not try to avoid writing dirty pages if we're above > the dirty buffers watermark. Agreed in theory.. I'll go try to measure. -Mike - 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/