From mboxrd@z Thu Jan 1 00:00:00 1970 From: Auke Kok Subject: Re: [e1000]: flow control on by default - good idea really? Date: Thu, 06 Jul 2006 11:25:54 -0700 Message-ID: <44AD55B2.3030900@intel.com> References: <1152033116.5276.22.camel@jzny2> <1152040839.5276.25.camel@jzny2> <20060705.112237.41652489.davem@davemloft.net> <44AC05A8.9030503@intel.com> <1152191018.5103.48.camel@jzny2> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Krzysztof Oledzki , jgarzik@pobox.com, greearb@candelatech.com, john.ronciak@intel.com, Robert.Olsson@data.slu.se, jesse.brandeburg@intel.com, netdev@vger.kernel.org, David Miller Return-path: Received: from mga03.intel.com ([143.182.124.21]:56644 "EHLO azsmga101-1.ch.intel.com") by vger.kernel.org with ESMTP id S1750728AbWGFSlR (ORCPT ); Thu, 6 Jul 2006 14:41:17 -0400 To: hadi@cyberus.ca In-Reply-To: <1152191018.5103.48.camel@jzny2> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org jamal wrote: > On Wed, 2006-05-07 at 22:45 +0200, Krzysztof Oledzki wrote: >> On Wed, 5 Jul 2006, Auke Kok wrote: >> >>> David Miller wrote: >>>> Flow control has been on by default in the tg3 driver since the >>>> beginning, > > Are you sure about this Dave?;-> because I do have a tg3 on my laptop. > > hadi@jzny2:~/Desktop/maemo$ sudo ethtool -a eth0 > Pause parameters for eth0: > Autonegotiate: on > RX: off > TX: off mine says it's on :) > Maybe it is read from the eeprom and mine has it off? > > Again, note that: It is consuming > 10% (13-15% range) of my bandwidth. > Granted that is at high speeds with small packets so may not be > reflective of 96% of the world. But that would be > 50kpps of my > forwarding capacity being chewed unreasonably. So Auke, did you say > "performance" was what people mostly bitched about? ;-> yes, but that's linked with hardware that doesn't handle flowcontrol events properly, if you were doing large message TCP transfers over that you'd probably see even worse performance I bet (retransmits being dropped etc). Jesse is working on performance stuff, he'll gladly look into it :) >>> As said earlier, e1000 always honors the EEPROM setting for this, which has >>> been _on_ by default for all cards (AFAIK, that is). > > It has _never ever_ worked on e1000 for as long as i have used e1000. If > it was intended to work, it must have been fixed in 2.6.16. So it is new > behavior. Turns out that of the e1000 cards I can find around here that are plugged in actually are 50-50 distributed on/off, so I was wrong about it being on by default everywhere. Looking back through the code I see no changes affecting flow control setup as early as 2.6.12 ... There are some minor (new) HW changes but nothing that should have boken fc. Cheers, Auke