From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH 2/2] [e1000 VLAN] Disable vlan hw accel when promiscuous mode Date: Tue, 13 Nov 2007 04:06:24 -0800 (PST) Message-ID: <20071113.040624.43544149.davem@davemloft.net> References: <20071113.033611.73195922.davem@davemloft.net> <20071113120328.GB1086@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: kaber@trash.net, joonwpark81@gmail.com, w@1wt.eu, cfriesen@nortel.com, auke-jan.h.kok@intel.com, netdev@vger.kernel.org, djohnson+linux-kernel@sw.starentnetworks.com, linux-kernel@vger.kernel.org, e1000-devel@lists.sourceforge.net To: herbert@gondor.apana.org.au Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:57117 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753944AbXKMMGY (ORCPT ); Tue, 13 Nov 2007 07:06:24 -0500 In-Reply-To: <20071113120328.GB1086@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Herbert Xu Date: Tue, 13 Nov 2007 20:03:28 +0800 > On Tue, Nov 13, 2007 at 03:36:11AM -0800, David Miller wrote: > > > > The performance implications can be pretty severe however. > > I wish we could address this somehow. > > Or perhaps we should just teach everyone to always run tcpdump > with -p, like me :) :-) > Of course this would still have a negative impact on those who > have to be in promiscuous mode all the time (heh) due to multiple > unicast MAC addresses and such. However, we should able to > communicate that fact to the driver and the driver can then elect > to not disable VLAN acceleration unless we really want to be in > promiscuous mode. We already do with the code Patrick added a while ago so that drivers can support multiple MAC addresses in hardware. Now just to get the virtualization technologies and all the drivers using it properly. > In other words we can make it so that nobody is in promiscuous > mode and therefore have to disable VLAN acceleration *unless* > they really want to be in that state. In which case it would > imply that they wish to see everything and therefore we should > disable VLAN acceleration. This is too complicated, we have multiple unicast MAC support in the driver API already, let's simply use it.