From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 27 Jun 2001 04:53:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 27 Jun 2001 04:53:31 -0400 Received: from mail.muc.eurocyber.net ([195.143.108.5]:37066 "EHLO mail.muc.eurocyber.net") by vger.kernel.org with ESMTP id ; Wed, 27 Jun 2001 04:53:20 -0400 Message-ID: <3B399EF8.9BA76FA2@TeraPort.de> Date: Wed, 27 Jun 2001 10:53:12 +0200 From: Martin Knoblauch Organization: TeraPort GmbH X-Mailer: Mozilla 4.77 [en] (X11; U; Linux 2.4.5-ac18 i686) X-Accept-Language: en, de MIME-Version: 1.0 To: "linux-kernel@vger.kernel.org" Subject: Re: VM Requirement Document - v0.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >> * If we're getting low cache hit rates, don't flush >> processes to swap. >> * If we're getting good cache hit rates, flush old, idle >> processes to swap. Rik> ... but I fail to see this one. If we get a low cache hit rate, Rik> couldn't that just mean we allocated too little memory for the Rik> cache ? maybe more specific: If the hit-rate is low and the cache is already 70+% of the systems memory, the chances maybe slim that more cache is going to improve the hit-rate. I do not care much whether the cache is using 99% of the systems memory or 50%. As long as there is free memory, using it for cache is great. I care a lot if the cache takes down interactivity, because it pushes out processes that it thinks idle, but that I need in 5 seconds. The caches pressure against processes should decrease with the (relative) size of the cache. Especially in low hit-rate situations. OT: I asked the question before somewhere else. Are there interfaces to the VM that expose the various cache sizes and, more important, hit-rates to userland? I would love to see (or maybe help writing in my free time) a tool to just visualize/analyze the efficiency of the VM system. Martin -- ------------------------------------------------------------------ Martin Knoblauch | email: Martin.Knoblauch@TeraPort.de TeraPort GmbH | Phone: +49-89-510857-309 C+ITS | Fax: +49-89-510857-111 http://www.teraport.de | Mobile: +49-170-4904759