From owner-freebsd-hackers Thu Sep 27 9:24:50 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by hub.freebsd.org (Postfix) with ESMTP id 41BB337B426 for ; Thu, 27 Sep 2001 09:24:45 -0700 (PDT) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.9.3/8.9.3) with ESMTP id MAA14130; Thu, 27 Sep 2001 12:24:36 -0400 (EDT) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.11.3/8.9.1) id f8RGOAI83899; Thu, 27 Sep 2001 12:24:10 -0400 (EDT) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15283.21162.173735.343154@grasshopper.cs.duke.edu> Date: Thu, 27 Sep 2001 12:24:10 -0400 (EDT) To: Ronald G Minnich Cc: "Louis A. Mamakos" , Subject: Re: TCP&IP cksum offload on FreeBSD 4.2 In-Reply-To: References: <15283.19536.410864.339942@grasshopper.cs.duke.edu> X-Mailer: VM 6.75 under 21.1 (patch 12) "Channel Islands" XEmacs Lucid Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Ronald G Minnich writes: > On Thu, 27 Sep 2001, Andrew Gallatin wrote: > > > At this level, you're basically screwed. A sofware checksum isn't > > even an option on other PCI users, like disk controllers. If you > > don't trust your PCI chipset, what do you do about things like that? > > > > I'm rather curious -- what was the problematic hardware combination? > > Can't say yet :-( > > But it is one of the fancy network interfaces that essentially runs an > RTOS on the NIC so it can "help you". Actually fancy $5000 network > interfaces are in general less reliable than your average garden-variety > $2 IDE chip. Partly because they have so much capability. > > So we don't worry a lot about lossage with IDE. But it's a big problem on > expensive, high end, high performance network interfaces. But SCSI isn't immune either. We had some data corruption problems with early adaptec Ultra-2 scsi controllers too, before Justin fixed it by working around it in the driver. Basically, anything that uses a PCI chipset harder or in different ways than its designers expected can end up being a problem. Low volume hardware is somtimes worse, but not always... Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message