From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: Default offload settings in Ethernet drivers Date: Thu, 11 Dec 2008 10:54:59 -0800 Message-ID: <20081211105459.3e615be8@s6510> References: <49415EDB.3030006@computer.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Jan Ceuleers Return-path: Received: from mail.vyatta.com ([76.74.103.46]:57101 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755082AbYLKSzI (ORCPT ); Thu, 11 Dec 2008 13:55:08 -0500 In-Reply-To: <49415EDB.3030006@computer.org> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 11 Dec 2008 19:41:31 +0100 Jan Ceuleers wrote: > Hi! > > A discussion recently took place on the power mailing list on the > subject of the impact of (hardware-assisted) offload functions on the > power efficiency of the overall system. > > The discussion was brought on by me noticing that not all drivers enable > all of their offload features by default (case in point: r8169). > > Although the discussion may not be complete, early indications are that: > > 1. Hardware-assisted offloads improve power efficiency unless > implemented in a separate CPU (TOE / Total Offloading); > > 2. It would probably be a good idea to enable hardware-assisted offloads > other than TOE by default given the above. > > I would therefore like to sollicit views here: > > 1. Would changing default offload settings in Ethernet drivers help to > save the planet? > > 2. Which offload settings does it make sense to enable by default? Go get a kill-a-watt meter and real hardware and measure. I don't think there will be any difference. Linux (mainline) doesn't do TOE. It does do segmentation offload, and any driver that can do segmentation offload enables it by default.