From owner-freebsd-questions@FreeBSD.ORG Thu Sep 11 09:43:28 2003 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6662116A4BF; Thu, 11 Sep 2003 09:43:28 -0700 (PDT) Received: from out003.verizon.net (out003pub.verizon.net [206.46.170.103]) by mx1.FreeBSD.org (Postfix) with ESMTP id 349B843FD7; Thu, 11 Sep 2003 09:43:27 -0700 (PDT) (envelope-from cswiger@mac.com) Received: from mac.com ([68.237.14.199]) by out003.verizon.net (InterMail vM.5.01.05.33 201-253-122-126-133-20030313) with ESMTP id <20030911164326.FEGY29617.out003.verizon.net@mac.com>; Thu, 11 Sep 2003 11:43:26 -0500 Message-ID: <3F60A613.3020405@mac.com> Date: Thu, 11 Sep 2003 12:42:59 -0400 From: Chuck Swiger Organization: The Courts of Chaos User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 X-Accept-Language: en-us, en MIME-Version: 1.0 References: <008501c3786a$95aaefa0$1916c60a@win2k.clickcom.com> <20030911090023.40d3f497.cpressey@catseye.mine.nu> In-Reply-To: <20030911090023.40d3f497.cpressey@catseye.mine.nu> X-Enigmail-Version: 0.76.5.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Authentication-Info: Submitted using SMTP AUTH at out003.verizon.net from [68.237.14.199] at Thu, 11 Sep 2003 11:43:26 -0500 cc: freebsd-performance@freebsd.org cc: freebsd-questions@freebsd.org Subject: Re: Performance Problems.. Server hardware smoked by $500 box? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Sep 2003 16:43:28 -0000 Chris Pressey wrote: [ ... ] > - Is it possible the server has too much RAM? > > I don't remember where I heard that that can degrade performance, but > I'm pretty sure it was on one of the freebsd lists a couple of months > ago. One of the early Pentium Pro/P2 chipsets, either the 430VX or the 430FX?, was unable to perform L2 caching of main memory above 64MB or some such, but aside from this sort of hardware limitation, more memory is going to be better for FreeBSD. [ This isn't true of all operating systems, but Unix systems like FreeBSD use some variant of LRU page replacement algorithm for VM, probably in conjunction with a global page-fault frequency algorithm to help size process working sets, which does not suffer from Belady's anomaly. At one point, Windows used FIFO with working set as the VM paging algorithm, which does not maintain the stack-based invariant of resident pages and thus sometimes making more memory available under Windows results in worse performance due to software issues. The classic MacOS used to have a similarly brain-dead VM system, which is why Mac users have generally resisted the notion of enabling or using VM, although they seem to be coping with Mach and Darwin.... ] -- -Chuck