From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nivedita Singhvi Subject: Re: [PATCH] Ethernet Bridging: Enable Hardware Checksumming Date: Thu, 19 May 2005 13:43:03 -0700 Message-ID: <428CFA57.1020501@us.ibm.com> References: <428CAC55.4000202@us.ibm.com> <20050519.115141.21926463.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: herbert@gondor.apana.org.au, jdmason@us.ibm.com, shemminger@osdl.org, netdev@oss.sgi.com Return-path: To: "David S. Miller" In-Reply-To: <20050519.115141.21926463.davem@davemloft.net> Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org David S. Miller wrote: > I think instead we should look at ways to propagate > the hardware device features to the bridge. Even if > a bridge is composed of multiple devices, we just > advertise the subset of features actually supported. Just for some background: In the typical Xen virtual environment, the primary interface is typically bridged with virtual interfaces that talk to other partitions. Since currently the bridge doesn't advertise them, this results in the loss of hw checksum offload, segmentation offload, and sendfile exploitation (sendfile() falls down to the usual tcp_sendmsg() case) etc on the primary partition traffic talking to remote hosts. This can be rather painful, and performance comparisons with other OSs which don't do this are even more of an apples to oranges comparison since this is somewhat silently happening. Hence the need for enhancing the bridging environment somewhat :). thanks, Nivedita