From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] Make possible speeds known to ethtool Date: Fri, 09 Jan 2009 01:28:22 -0500 Message-ID: <4966EE86.3030704@pobox.com> References: <20090109041952.GA12087@gondor.apana.org.au> <4966DABD.1000203@pobox.com> <20090109051500.GA12836@gondor.apana.org.au> <4966E0ED.9090905@pobox.com> <20090109053520.GA13219@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: bhutchings@solarflare.com, rick.jones2@hp.com, davem@davemloft.net, netdev@vger.kernel.org To: Herbert Xu Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:59723 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752447AbZAIG2f (ORCPT ); Fri, 9 Jan 2009 01:28:35 -0500 In-Reply-To: <20090109053520.GA13219@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: Herbert Xu wrote: > On Fri, Jan 09, 2009 at 12:30:21AM -0500, Jeff Garzik wrote: >> Actually it's just the opposite -- _the_ most common complaint from >> users and driver developers of the ethtool interface, over the years, >> has been that there is no way to collect all the modifications and then >> commit it to hardware all in one go. > > Yes that's a problem for flags that require the drivers to reset > itself. > >> Each new ethtool command added often winds up pausing and resetting the >> hardware completely, and ETHTOOL_SGRO is no exception. > > But as I explained before, GRO (like GSO) is purely a software > setting, it has nothing to do with the driver at all. In other Not quite true... it touches the driver's rx-csum hook. > If anything by going into the driver's set_flags function as you > suggested may cause a spurious reset that wouldn't have happened > otherwise. > > So for software flags like GSO/GRO at least, I don't see any > benefit in going to a multi-bit interface. On the flip side, > I see potential complications with a multi-bit interfaces that > simply don't exist with a single-bit interface. Well, whichever. Overall, if [GS]GRO remains I am happy to take patches supporting it in the userspace utility... Jeff