From owner-freebsd-current Wed Jul 30 20:17:43 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id UAA27327 for current-outgoing; Wed, 30 Jul 1997 20:17:43 -0700 (PDT) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id UAA27315; Wed, 30 Jul 1997 20:17:24 -0700 (PDT) Received: (from msmith@localhost) by genesis.atrad.adelaide.edu.au (8.8.5/8.7.3) id MAA25355; Thu, 31 Jul 1997 12:47:07 +0930 (CST) From: Michael Smith Message-Id: <199707310317.MAA25355@genesis.atrad.adelaide.edu.au> Subject: Re: code talks: announcing EIDE bus master patches In-Reply-To: <19970730220038.02422@mi.uni-koeln.de> from Stefan Esser at "Jul 30, 97 10:00:38 pm" To: se@FreeBSD.ORG (Stefan Esser) Date: Thu, 31 Jul 1997 12:47:07 +0930 (CST) Cc: gallatin@cs.duke.edu, freebsd-current@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-freebsd-current@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Stefan Esser stands accused of saying: > > (*) PCI device == a Myrinet M2F-PCI32 card. This is a programmable > > gigabit networking card. It has a 256k bank of SRAM on the card, and > > is very good for doing things like measuring PCI b/w. The tests were > > done from user space operating on mmap'ed device memory & a kernel > > allocated chunk of RAM to do DMA xfers to/from. It also runs IP > > traffic at better than 300Mb/sec. > > This was a memory mapped device buffer ? > > That's *very* different from an I/O port, and you should be able > to copy data to that SRAM at a much higher rate than 8 or 13MB/s! If I read the AMCC PCI matchmaker databook correctly, PIO to a memory-mapped buffer is likely to be severely affected by whether the PCI bridge in question supports cache line read/write operations. Is this a potential issue here? -- ]] 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 [[