From owner-freebsd-current Sat Jan 23 18:39:13 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id SAA24384 for freebsd-current-outgoing; Sat, 23 Jan 1999 18:39:13 -0800 (PST) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from spinner.netplex.com.au (spinner.netplex.com.au [202.12.86.3]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id SAA24372 for ; Sat, 23 Jan 1999 18:39:08 -0800 (PST) (envelope-from peter@netplex.com.au) Received: from spinner.netplex.com.au (localhost [127.0.0.1]) by spinner.netplex.com.au (8.9.2/8.9.2/Netplex) with ESMTP id KAA01206; Sun, 24 Jan 1999 10:13:33 +0800 (WST) (envelope-from peter@spinner.netplex.com.au) Message-Id: <199901240213.KAA01206@spinner.netplex.com.au> X-Mailer: exmh version 2.0.2 2/24/98 To: Matthew Dillon cc: N , current@FreeBSD.ORG Subject: Re: panic: found dirty cache page 0xf046f1c0 In-reply-to: Your message of "Sat, 23 Jan 1999 17:46:21 PST." <199901240146.RAA54333@apollo.backplane.com> Date: Sun, 24 Jan 1999 10:13:32 +0800 From: Peter Wemm Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Matthew Dillon wrote: > :But that was a week ago, and it's a *busy* news server (that's not hitting > :swap), I was just curious about the error messages from the de driver. > : > : -- Niels. > > The transmit underflow messages: > > de0: abnormal interrupt: transmit underflow (raising TX threshold to 96|256) > de0: abnormal interrupt: transmit underflow (raising TX threshold to 128|512) > de0: abnormal interrupt: transmit underflow (raising TX threshold to 160|1024 ) > > can typically be ignored. It simply means that the DEC card has too smal l > a transmit FIFO and is getting DMA underflows. Stupid card. As I understand it, what's happening is that it's reacting to pci bus congestion by raising the preread threshholds. It degenerates to fetching the entire frame into on-card (or chip) memory before beginning transmission. On my system I can understand it, it's a 2xP5 with a shared L2 cache on a Neptune chipset - something that isn't known for speed. Once you get two processors hammering the system bus, *plus* mix in an EISA scsi controller, I could well imagine the memory bus getting thrashed. I'm not sure how to read the messages. Looking at the if_pn driver as well, it looks like both start with a FIFO threshold of 72 bytes. I think that '160|1024' (for example) means start transmitting when the FIFO has fetched 160 bytes and don't stop fetching unless we hit 1024 bytes in the fifo. Store and forward mode (I believe) is a degenerate case where it fetches the entire packet into the buffer before beginning transmission. Bill Paul's if_pn driver doesn't react to an underflow at all.. it stays at 72/128 permanently. For what it's worth, the de cards are the only ones I've found that can work at all on this system at 100Mbit. The realtek 8139 cards (cheap!) went belly-up on the spot, no suprise there. I don't have an fxp card to test. > -Matt Cheers, -Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message