Date: Thu, 27 Sep 2001 10:21:38 -0400 (EDT) From: Andrew Gallatin <gallatin@cs.duke.edu> To: <hackers@FreeBSD.ORG> Cc: Ronald G Minnich <rminnich@lanl.gov> Subject: Re: TCP&IP cksum offload on FreeBSD 4.2 Message-ID: <15283.13810.632100.547964@grasshopper.cs.duke.edu> In-Reply-To: <Pine.LNX.4.33.0109270728220.26552-100000@snaresland.acl.lanl.gov> References: <15283.10378.718858.212593@grasshopper.cs.duke.edu> <Pine.LNX.4.33.0109270728220.26552-100000@snaresland.acl.lanl.gov>
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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
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