From owner-freebsd-atm Tue Jan 16 10:29:14 2001 Delivered-To: freebsd-atm@freebsd.org Received: from mail.matriplex.com (ns1.matriplex.com [208.131.42.8]) by hub.freebsd.org (Postfix) with ESMTP id 6723637B404 for ; Tue, 16 Jan 2001 10:28:57 -0800 (PST) Received: from mail.matriplex.com (mail.matriplex.com [208.131.42.9]) by mail.matriplex.com (8.9.2/8.9.2) with ESMTP id KAA00993; Tue, 16 Jan 2001 10:28:53 -0800 (PST) (envelope-from rh@matriplex.com) Date: Tue, 16 Jan 2001 10:28:52 -0800 (PST) From: Richard Hodges To: Mike Tancsa Cc: freebsd-atm@FreeBSD.ORG Subject: Re: ATM under 4.x STABLE (DMA and en driver ?) In-Reply-To: <5.0.1.4.0.20010116121839.033a2a70@marble.sentex.ca> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-atm@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Tue, 16 Jan 2001, Mike Tancsa wrote: > At 09:18 AM 1/16/01 -0800, Richard Hodges wrote: > >On Tue, 16 Jan 2001, Mike Tancsa wrote: > > > > > > en0: mem 0xfe000000-0xfe3fffff irq 11 at > > > device 8.0 on pci1 > > > en0: unexpected timeout in rx DMA test > > > en0: WARNING: DMA test detects a broken PCI chipset! > > > trying to work around the problem... but if this doesn't > > > work for you, you'd better switch to a newer motherboard. > > Your DMA message above seems to refer to the chipset not being able > > to handle "misaligned 64 byte DMA", which might not be a major > > problem, but just might reduce the performance. > Hmmm... Any guesses as to how much of a performance drop ? Gueses? Sure :-) I think this is referring to the longest burst of data that the card can push through the PCI bus at a time. Since you need one PCI cycle for setup, your max PCI throughput would be roughly 133MB/sec / (4 + burstlen). Obviously, 64-byte bursts will be more productive than 4-byte bursts (50% wasted) for example. > BTW, for my simple protocol requirements, should I try and pick up a couple > of used Fore cards instead ? I am hoping the box will be able to forward > 30-50Mb/s over its life time. That should be no problem at all. I rarely see better than 80mb/sec on an FTP file transfer, but for raw throughput you should be able to reach 120+ Unless the Efficient card is *really* broken, I assume you should see comparable results. -Richard ------------------------------------------- Richard Hodges | Matriplex, inc. | 769 Basque Way rh@matriplex.com | Carson City, NV 89706 775-886-6477 | www.matriplex.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-atm" in the body of the message