From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265396AbUEZJsP (ORCPT ); Wed, 26 May 2004 05:48:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265395AbUEZJsP (ORCPT ); Wed, 26 May 2004 05:48:15 -0400 Received: from smtp014.mail.yahoo.com ([216.136.173.58]:3248 "HELO smtp014.mail.yahoo.com") by vger.kernel.org with SMTP id S265386AbUEZJsN (ORCPT ); Wed, 26 May 2004 05:48:13 -0400 Message-ID: <40B467DA.4070600@yahoo.com.au> Date: Wed, 26 May 2004 19:48:10 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040401 Debian/1.6-4 X-Accept-Language: en MIME-Version: 1.0 To: John Bradford CC: Buddy Lumpkin , "'William Lee Irwin III'" , orders@nodivisions.com, linux-kernel@vger.kernel.org Subject: Re: why swap at all? References: <40B4590A.1090006@yahoo.com.au> <200405260934.i4Q9YblP000762@81-2-122-30.bradfords.org.uk> In-Reply-To: <200405260934.i4Q9YblP000762@81-2-122-30.bradfords.org.uk> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org John Bradford wrote: > Quote from Nick Piggin : > >>Even for systems that don't *need* the extra memory space, swap can >>actually provide performance improvements by allowing unused memory >>to be replaced with often-used memory. > > > That's true, but it's not a magical property of swap space - extra physical > RAM would do more or less the same thing. > Well it is a magical property of swap space, because extra RAM doesn't allow you to replace unused memory with often used memory. The theory holds true no matter how much RAM you have. Swap can improve performance. It can be trivially demonstrated.