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, 6 Jun 2001 12:40:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 6 Jun 2001 12:40:00 -0400 Received: from cx97923-a.phnx3.az.home.com ([24.9.112.194]:2971 "EHLO grok.yi.org") by vger.kernel.org with ESMTP id ; Wed, 6 Jun 2001 12:39:49 -0400 Message-ID: <3B1E64EA.8F4FD7C9@candelatech.com> Date: Wed, 06 Jun 2001 10:14:18 -0700 From: Ben Greear Organization: Candela Technologies X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.4.2-2 i686) X-Accept-Language: en MIME-Version: 1.0 To: Richard Gooch CC: Daniel Phillips , Sean Hunter , Xavier Bestel , linux-kernel@vger.kernel.org Subject: Re: Break 2.4 VM in five easy steps In-Reply-To: <3B1D5ADE.7FA50CD0@illusionary.com> <991815578.30689.1.camel@nomade> <20010606095431.C15199@dev.sportingbet.com> <0106061316300A.00553@starship> <200106061528.f56FSKa14465@vindaloo.ras.ucalgary.ca> 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 Richard Gooch wrote: > > Daniel Phillips writes: > > On Wednesday 06 June 2001 10:54, Sean Hunter wrote: > > > > > > Did you try to put twice as much swap as you have RAM ? (e.g. add a > > > > 512M swapfile to your box) > > > > This is what Linus recommended for 2.4 (swap = 2 * RAM), saying > > > > that anything less won't do any good: 2.4 overallocates swap even > > > > if it doesn't use it all. So in your case you just have enough swap > > > > to map your RAM, and nothing to really swap your apps. > > > > > > For large memory boxes, this is ridiculous. Should I have 8GB of > > > swap? > > Sure. It's cheap. If you don't mind slumming it, go and buy a 20 GB > IDE drive for US$65. I know RAM has gotten a lot cheaper lately (US$66 > for a 512 MiB PC133 DIMM), but it's still far more expensive. If you > can afford 4 GiB of RAM, you can definately afford 8 GiB of swap. For me, the problem is not the money. If I have a system that needs 4GB of RAM, it is highly unlikely that I would ever want to be running this machine with 8GB of swap active. However, I may be willing to tollerate 1GB of swapping before paging to disk slowed things down too much. This is the exact scenario I had when dealing with a large Sun machine running Oracle & some other stuff. Oracle is dedicated large amounts of RAM, but if I wanted to run a quick, memory intensive program too, (and at the moment performance isn't all that big of a deal), then using some swap is OK. So, I too cast my vote for the 2*RAM requiment to be odious and in need of fixing!! It could be a suggestion, but I would consider that if not following the suggestion caused more than 10% slowdown, then things are still broken, and optimally, it should work like the 2.2 does (in other words, I don't notice, and don't particularly care how much swap per RAM I need, just how much total RAM-like-stuff I need.) Thanks, Ben -- Ben Greear President of Candela Technologies Inc http://www.candelatech.com ScryMUD: http://scry.wanfear.com http://scry.wanfear.com/~greear