From: Benny Amorsen Subject: Re: [PATCH 2/2] [e1000 VLAN] Disable vlan hw accel when promiscuous mode Date: Wed, 14 Nov 2007 12:48:04 +0100 Message-ID: References: <47365200.0f10240a.0686.2173@mx.google.com> <47388988.1000506@intel.com> <47388B9F.7050308@trash.net> <20071112.143342.10809862.davem@davemloft.net> <4738D70C.4060404@nortel.com> <4738D9AB.8080408@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: e1000-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org To: netdev@vger.kernel.org Return-path: Received: from main.gmane.org ([80.91.229.2]:33108 "EHLO ciao.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754709AbXKNLsY (ORCPT ); Wed, 14 Nov 2007 06:48:24 -0500 Received: from list by ciao.gmane.org with local (Exim 4.43) id 1IsGjE-0002bQ-NS for netdev@vger.kernel.org; Wed, 14 Nov 2007 11:48:20 +0000 Received: from hd5b9080a.c45-01-12.sta.perspektivbredband.net ([213.185.8.10]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 14 Nov 2007 11:48:20 +0000 Received: from benny+usenet by hd5b9080a.c45-01-12.sta.perspektivbredband.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 14 Nov 2007 11:48:20 +0000 Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org >>>>> "AK" == Kok, Auke writes: AK> actually the impact can be quite negative, imagine doing a tcpdump AK> on a 10gig interface with vlan's enabled - all of a sudden you AK> might accidentally flood the system with a 100-fold increase in AK> traffic and force the stack to dump all those packets for you. Why is the switch sending you all that traffic for VLAN's you don't care about? I have a hard time imagining such a scenario. Sure, you could have forgotten to limit the VLAN range sent to a particular host, or even have decided that it's administratively easier to just allow everything, but the switch still won't send unicast traffic out that port unless the destination MAC matches. If broadcast or non-solicited multicast takes up most of your bandwidth, you have other problems. /Benny