From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck Subject: Re: [net-next 11/13] igb: Make Tx budget for NAPI user adjustable Date: Mon, 19 Sep 2011 15:27:32 -0700 Message-ID: <4E77C1D4.503@intel.com> References: <4E776441.9090602@intel.com> <1316448352.2764.27.camel@bwh-desktop> <4E776E92.6090303@intel.com> <20110919.170033.344802441047363137.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: bhutchings@solarflare.com, jeffrey.t.kirsher@intel.com, netdev@vger.kernel.org, gospo@redhat.com To: David Miller Return-path: Received: from mga02.intel.com ([134.134.136.20]:48597 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932429Ab1ISW0u (ORCPT ); Mon, 19 Sep 2011 18:26:50 -0400 In-Reply-To: <20110919.170033.344802441047363137.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On 09/19/2011 02:00 PM, David Miller wrote: > From: Alexander Duyck > Date: Mon, 19 Sep 2011 09:32:18 -0700 >> The fact is ixgbe has been using this parameter this way for over 2 >> years now and the main goal of this patch was just to synchronize how >> things work on igb and ixgbe. >> >> Our hardware doesn't have a mechanism for firing an interrupt after X >> number of frames so instead we simply have modified things so that we >> will only process X number of frames and then fire another >> interrupt/poll if needed. As such we aren't that far out of >> compliance with the meaning of how this parameter is supposed to be >> used. > All I can say is this was a huge mistake you therefore need to revert > the IXGBE change, these ethtool settings are not for changing NAPI or > software interrupt behavior. > > And if you guys plan to be difficult on this and refuse to remove the > IXGBE bits, I'm letting you guys know ahead of time that I'll do it > for you. > > If the hardware can't support this facility, neither should these > ethtool hooks, because the whole point is to avoid hardware interrupts > from firing using these parameters. > > Propose new mechanisms to control NAPI behavior if you want. I'll remove the ixgbe code if that is what you want. It may be a month or so before I can get to it though since I am slammed with work so if you are in a hurry for it you might want to work with Jeff Kirsher to have the code removed. As far as this current patch goes I honestly don't have the time to add or rewrite yet another ethtool interface so I will probably just see about dropping the ethtool portion of this patch and update the description in order to make it acceptable. Thanks, Alex