From owner-freebsd-questions@FreeBSD.ORG Thu Nov 27 15:28:27 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 40D4616A4CF for ; Thu, 27 Nov 2003 15:28:27 -0800 (PST) Received: from rutger.owt.com (rutger.owt.com [204.118.6.16]) by mx1.FreeBSD.org (Postfix) with ESMTP id B57A643FBD for ; Thu, 27 Nov 2003 15:28:25 -0800 (PST) (envelope-from kstewart@owt.com) Received: from topaz-out (owt-207-41-94-233.owt.com [207.41.94.233]) by rutger.owt.com (8.11.6p2/8.9.3) with ESMTP id hARNSIu01032; Thu, 27 Nov 2003 15:28:18 -0800 From: Kent Stewart To: JacobRhoden , Uwe Doering , freebsd-questions@freebsd.org Date: Thu, 27 Nov 2003 15:28:18 -0800 User-Agent: KMail/1.5.4 References: <200311261658.34693.fbsd-questions@trini0.org> <3FC672EC.1000904@geminix.org> <200311281010.01899.jrhoden@unimelb.edu.au> In-Reply-To: <200311281010.01899.jrhoden@unimelb.edu.au> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200311271528.18216.kstewart@owt.com> Subject: Re: Multiple CPU Performance 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, 27 Nov 2003 23:28:27 -0000 On Thursday 27 November 2003 03:10 pm, JacobRhoden wrote: > > Gerard Samuel wrote: > > > I was fortunate to acquire a dual Slot one motherboard. > > > I currently only have one PIII 450 in there, and its working without > > > any problems so far. > > > This box is primarily for www/samba/cvs. > > > I was wondering if my PHP apps would benefit (run faster) if I > > > introduced a 2nd CPU. > > I am no expert on this sort of thing, but I thought I should add one thing, > in case you havent thought of it... What is the load on your cpu? It can > be found by doing a top.. if it never reaches 1.0 while running php apps, > then an extra cpu is not going to make much difference. In general I have > found that the bottleneck in older computers tends to be the hard drive, > not the CPU. > I saw a comment recently that stood out. It was to the effect that SMP lets you run more applications at the same speed. On buildworlds, for example, the suggestion is to use -j4 on single cpu systems. I find the -j4 runs a buildworld 20-30% slower than no -j at all. The -j8 ran faster on SMP. The process of running multiple makes has a process switching overhead that costs me time. I also have IDE HDs and suspect that the tagged queuing built into good scsi HDs gets around some of the HD bottle neck. Kent -- Kent Stewart Richland, WA http://users.owt.com/kstewart/index.html