From owner-freebsd-hackers Thu Sep 27 7:22:21 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 2DBB837B401 for ; Thu, 27 Sep 2001 07:22:16 -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 KAA10853; Thu, 27 Sep 2001 10:22:04 -0400 (EDT) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.11.3/8.9.1) id f8RELcY83736; Thu, 27 Sep 2001 10:21:38 -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: <15283.13810.632100.547964@grasshopper.cs.duke.edu> Date: Thu, 27 Sep 2001 10:21:38 -0400 (EDT) To: Cc: Ronald G Minnich Subject: Re: TCP&IP cksum offload on FreeBSD 4.2 In-Reply-To: References: <15283.10378.718858.212593@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: > I have a question on the checksum offloading. Has anyone measured any > incidence of data corruption between the PCI card and memory. In other > words, when you offload checksums the end-to-end checking becomes > card-to-card checking, and the possibility exists that what goes in memory > at the destination end is not what was sent at the source. Very remote > possibility, of course, but ... We used to see occasional data corruption at Duke with 440BX based motherboards with non-ecc ram. We never saw it on higher-quality hosts (alphas or serverworks based pc motherboards) with ecc memory. It would manifest itself as bad TCP checksums (no csum offload at the time). > of these types of problems (of course FreeBSD has the fastest IP over > Myrinet anyway, so it's not like that's a huge problem). > Not any more. A 2.4 linux kernel will do a bit better than FreeBSD on an SMP box because it is able to use both processors. Speaking of which -- who is working on making the network stack SMP capable in -current? Anything I can do to help? Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message