From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: NIC data corruption Date: Mon, 2 Apr 2007 20:07:17 +0200 Message-ID: <20070402180717.GA32435@one.firstfloor.org> References: <20070401012736.GT15189@vitelus.com> <20070401030315.GA24080@jim.sh> <20070401043905.GV15189@vitelus.com> <46114158.2030007@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , Aaron Lehmann , Jim Paris , netdev@vger.kernel.org To: Rick Jones Return-path: Received: from one.firstfloor.org ([213.235.205.2]:37707 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965621AbXDBSHX (ORCPT ); Mon, 2 Apr 2007 14:07:23 -0400 Content-Disposition: inline In-Reply-To: <46114158.2030007@hp.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, Apr 02, 2007 at 10:46:00AM -0700, Rick Jones wrote: > I changed the title to be more accurate, and culled the distribution to > individuals and netdev > > The mention of trying to turn-off CKO and see if the data corruption > goes away leads me to ask a possibly "delicate" question: > > Should "Linux" only enable CKO on those NICs certified to have > ECC/parity throughout their _entire_ data path? Even with reliable software checksumming you can have quite a lot of undetected errors (there was a interesting study about this some years ago). If you really care about your data you should use SSL or some other protocol with strong checksums. That said it would probably make quite a lot of people unhappy because it would make their NICs much slower and the occasional bit error that is missed by the NIC is likely not a big issue for them. What might be a good idea would to have some optional knob somewhere that allows to disable hardware checksumming for NICs that are not trusted this way. But then someone would need to do the necessary research for the hundreds of NICs Linux support Just providing a general global "disable hardware checksumming" knob for the paranoid would be much easier. I guess that would be a good idea. -Andi