From owner-freebsd-hackers Thu Feb 3 11:40:29 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from feral.com (feral.com [192.67.166.1]) by builder.freebsd.org (Postfix) with ESMTP id B207B3E65 for ; Thu, 3 Feb 2000 11:40:21 -0800 (PST) Received: from semuta.feral.com (semuta [192.67.166.70]) by feral.com (8.9.3/8.9.3) with ESMTP id LAA20437; Thu, 3 Feb 2000 11:36:13 -0800 Date: Thu, 3 Feb 2000 11:36:10 -0800 (PST) From: Matthew Jacob Reply-To: mjacob@feral.com To: "Kenneth D. Merry" Cc: Thomas Stromberg , freebsd-hackers@FreeBSD.ORG Subject: Re: Suggestions for Gigabit cards for -CURRENT In-Reply-To: <20000203122953.A53875@panzer.kdm.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > On Thu, Feb 03, 2000 at 11:23:45 -0800, Matthew Jacob wrote: > > > > > > I think the memory would come in handy on a heavily loaded system, since > > > you would gain a little extra time in case you were a little late servicing > > > interrupts. i.e. it would smooth out the bumps a little bit. > > > > Yes, but that's what having 8192 2KByte descriptors handy is for... (that's > > 16MB of buffering). > > Are those all in card memory, or in host memory? What happens when you've > got some other traffic on the PCI bus, and the card gets a little behind > in DMAing its data into host memory? They're in host memory, and that's why I said "performance is contingent on PCI bus implementation". I think that 64K of FIFO is adequate flow control for PCI traffic avoidance. > > > If your PCI implementation won't keep up with gigabit speeds, you'll just > > > go slower. :) Most newer systems (e.g. 440BX) shouldn't have any trouble > > > doing a reasonable amount of speed over gigabit ethernet, though. > > > > Typically I don't see higher than 60 or 70MB/s real throughput on most > > systems. > > I've seen 100MB/sec on Pentium II 450's (440BX), and 90MB/sec on Pentium II > 350's (440BX). Aw, it just means your employers buy you up to date systems....unlike po' lil' me... :-( To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message