From owner-freebsd-current Wed Nov 1 22:33:39 2000 Delivered-To: freebsd-current@freebsd.org Received: from implode.root.com (root.com [209.102.106.178]) by hub.freebsd.org (Postfix) with ESMTP id 30B4B37B479 for ; Wed, 1 Nov 2000 22:33:37 -0800 (PST) Received: from implode.root.com (localhost [127.0.0.1]) by implode.root.com (8.8.8/8.8.5) with ESMTP id WAA12676; Wed, 1 Nov 2000 22:31:41 -0800 (PST) Message-Id: <200011020631.WAA12676@implode.root.com> To: janb@cs.utep.edu Cc: freebsd-current@FreeBSD.ORG Subject: Re: current paging strategy In-reply-to: Your message of "Wed, 01 Nov 2000 21:34:25 MST." From: David Greenman Reply-To: dg@root.com Date: Wed, 01 Nov 2000 22:31:40 -0800 Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >What paging strategy does FreeBSD currently use? Is it LRU or some >approximation to it? How much memory does this strategy take up in its >current implementation? It's probably nothing like anything you've heard of before. It's closest to LOU (least often used). We look at the page's reference flag and increment/decrement a counter depending on it. The rate that we look at the reference flag is also roughly proportional to the rate at which new pages are needed. This algorithm has proven to be extremely effective and does much better than simple LRU. -DG David Greenman Co-founder, The FreeBSD Project - http://www.freebsd.org President, TeraSolutions, Inc. - http://www.terasolutions.com Pave the road of life with opportunities. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message