From owner-freebsd-hardware Tue Feb 25 00:29:18 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id AAA09642 for hardware-outgoing; Tue, 25 Feb 1997 00:29:18 -0800 (PST) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id AAA09630 for ; Tue, 25 Feb 1997 00:29:14 -0800 (PST) Received: (from msmith@localhost) by genesis.atrad.adelaide.edu.au (8.8.5/8.7.3) id SAA14217; Tue, 25 Feb 1997 18:59:01 +1030 (CST) From: Michael Smith Message-Id: <199702250829.SAA14217@genesis.atrad.adelaide.edu.au> Subject: Re: Memory speed of P6-200 (256k) In-Reply-To: <199702250819.TAA02011@godzilla.zeta.org.au> from Bruce Evans at "Feb 25, 97 07:19:41 pm" To: bde@zeta.org.au (Bruce Evans) Date: Tue, 25 Feb 1997 18:58:59 +1030 (CST) Cc: ken@stox.pr.mcs.net, msmith@atrad.adelaide.edu.au, freebsd-hardware@freebsd.org X-Mailer: ELM [version 2.4ME+ PL28 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hardware@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Bruce Evans stands accused of saying: > >As Bruce has observed, this makes for very healthy IDE performance, > >which is what this whole thread started with. > > Er, no, fast copying reduces buffer cache overheads. Buffer cache > overheads are almost large enough to significantly reduce the advantages > of busmastering DMA over (slow) PIO. ie. the fast copyin/out code will make busmaster devices faster too? 8) > Bruce -- ]] Mike Smith, Software Engineer msmith@gsoft.com.au [[ ]] Genesis Software genesis@gsoft.com.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control. (ph) +61-8-8267-3493 [[ ]] Unix hardware collector. "Where are your PEZ?" The Tick [[