From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: [e1000 2.6 10/11] TxDescriptors -> 1024 default Date: Thu, 11 Sep 2003 12:45:55 -0700 Sender: netdev-bounce@oss.sgi.com Message-ID: <3F60D0F3.8080006@candelatech.com> References: <3F60CA6D.9090503@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: "Feldman, Scott" , netdev@oss.sgi.com, ricardoz@us.ibm.com Return-path: To: Jeff Garzik In-Reply-To: <3F60CA6D.9090503@pobox.com> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Jeff Garzik wrote: > Feldman, Scott wrote: > >> * Change the default number of Tx descriptors from 256 to 1024. >> Data from [ricardoz@us.ibm.com] shows it's easy to overrun >> the Tx desc queue. > > > > All e1000 patches applied except this one. > > Of _course_ it's easy to overrun the Tx desc queue. That's why we have > a TX queue sitting on top of the NIC's hardware queue. And TCP socket > buffers on top of that. And similar things. > > Descriptor increases like this are usually the result of some sillyhead > blasting out UDP packets, and then wondering why he sees packet loss on > the local computer (the "blast out packets" side). Erm, shouldn't the local machine back itself off if the various queues are full? Some time back I looked through the code and it appeared to. If not, I think it should. > > You're just wasting memory. > > Jeff > > > -- Ben Greear Candela Technologies Inc http://www.candelatech.com