From owner-freebsd-questions Mon Feb 24 14:40:44 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id OAA25098 for questions-outgoing; Mon, 24 Feb 1997 14:40:44 -0800 (PST) Received: from zwei.siemens.at (zwei.siemens.at [193.81.246.12]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id OAA25081 for ; Mon, 24 Feb 1997 14:40:28 -0800 (PST) Received: from sol1.gud.siemens.co.at (root@[10.1.143.100]) by zwei.siemens.at (8.7.5/8.7.3) with SMTP id XAA27911 for ; Mon, 24 Feb 1997 23:41:47 +0100 (MET) Received: from ws2301.gud.siemens.co.at by sol1.gud.siemens.co.at with smtp (Smail3.1.28.1 #7 for ) id m0vz93d-0001xrC; Mon, 24 Feb 97 23:39 MET Received: by ws2301.gud.siemens.co.at (1.37.109.16/1.37) id AA204803746; Mon, 24 Feb 1997 23:35:46 +0100 From: "Hr.Ladavac" Message-Id: <199702242235.AA204803746@ws2301.gud.siemens.co.at> Subject: Re: Adding memory slows down 486 to less than 386SX! To: bdodson@beowulf.utmb.edu (M. L. Dodson) Date: Mon, 24 Feb 1997 23:35:46 +0100 (MEZ) Cc: freebsd-questions@FreeBSD.ORG In-Reply-To: <199702242128.PAA08444@beowulf.utmb.EDU> from "M. L. Dodson" at Feb 24, 97 03:28:01 pm X-Mailer: ELM [version 2.4 PL24 ME8a] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-questions@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk E-mail message from M. L. Dodson contained: > > Hello, > > I just upgraded a 486DX-25 from 8MB to 20MB memory and sequential > character disk I/O to a SCSI disk is now slower than to an IDE disk > on a 386SX! > > The machine "feels" slow, also. Not only under FreeBSD, but also under > Win95 (for processes that do not cause swapping). I have included bonnie > results below. The 486 has a VLB BusLogic 445C bus mastering SCSI > controller, the 386SX a normal IDE builtin. Note that the 486 is 4-5X > faster for block I/O, which is what I was expecting for everything. The > kernels do not have bounce buffers enabled. Both machines were lightly > loaded. The 486 is a NFS server, the 386SX is a NFS client (it will > eventually be a router for my home network, but ppp was not running > during these benchmarks). Nothing was NFS mounted. > > The BIOS setup for the 486 is standard as far as I can tell: 2-1-1-1 > memory timing, 256KB cache was enabled, no cache waitstates. The 386 > was box stock, also, as far as I know. I have no documentation on > the 386 builtin controller, but BSD probes it as a standard IDE > controller. > > I don't get any memory fault indications. > > Note that the 386SX is only running a 10MB bonnie file, whereas the 486 > was running a 30MB. But I am talking sequential input/output, per > character, rates: 82K/sec vs 55K/sec output and 87K/sec vs 64K/sec for > input. > > And why is CPU utilization so high for the block I/O on the 486 > relative to the 386SX? > > Any help would be appreciated. I'm at a loss. > > Bud Dodson How much Level-2 cache do you have on the '486 board? Some boards could only cache the lower 16MB unless you had more than 128K cache. Mine was one of these :( /Marino