From owner-freebsd-hackers Thu Mar 7 13: 4:41 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from root.com (unknown [209.102.106.178]) by hub.freebsd.org (Postfix) with ESMTP id 36AC237B402 for ; Thu, 7 Mar 2002 13:04:34 -0800 (PST) Received: (from dg@localhost) by root.com (8.11.2/8.11.2) id g27Kqaf67063; Thu, 7 Mar 2002 12:52:36 -0800 (PST) (envelope-from dg) Date: Thu, 7 Mar 2002 12:52:36 -0800 From: David Greenman To: Matthew Dillon Cc: "Rogier R. Mulhuijzen" , Mike Silbersack , Tom , Dimitar Peikov , cjp , freebsd-hackers@FreeBSD.ORG Subject: Re: Swapping performance Message-ID: <20020307125236.E64508@nexus.root.com> References: <20020307095452.D18855-100000@frond.minions.com> <5.1.0.14.0.20020307193205.01c3b0f0@mail.drwilco.net> <200203071912.g27JC3A68645@apollo.backplane.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200203071912.g27JC3A68645@apollo.backplane.com>; from dillon@apollo.backplane.com on Thu, Mar 07, 2002 at 11:12:03AM -0800 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > Another point that I should bring up in regards to swap performance: > systems that require good swap performance will almost always have > more then one physical disk to swap to. FreeBSD is very good at > paging to swap with a single disk, but it kicks ass paging to swap > with multiple disks because it implements a very good interleaving > algorithm. I think it's also useful to point out that the performance of this test is likely going to vary greatly as it is run. This is because it is heavily affected by the order of the pageouts in terms of their physical swap block allocations. In other words, what you're really testing is how sequentially the blocks are paged out vs. how randomly at the swap block level. -DG David Greenman Co-founder, The FreeBSD Project - http://www.freebsd.org President, TeraSolutions, Inc. - http://www.terasolutions.com President, Download Technologies, Inc. - http://www.downloadtech.com Pave the road of life with opportunities. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message