From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck Subject: Re: igb mtu change Date: Wed, 17 Oct 2012 13:09:46 -0700 Message-ID: <507F108A.3080308@intel.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: e1000-devel@lists.sourceforge.net, linux-net@vger.kernel.org, netdev@vger.kernel.org To: ratheesh kannoth Return-path: Received: from mga14.intel.com ([143.182.124.37]:28918 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756303Ab2JQUJr (ORCPT ); Wed, 17 Oct 2012 16:09:47 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On 10/17/2012 07:41 AM, ratheesh kannoth wrote: > igb_change_mtu change is only changing adapter->rx_ring[0]->rx_buffer_len. > > 1) we dont have to change adapter->tx_ring[0]->rx_buffer_len ? > 2) Is there any way to set different values to > adapter->tx_ring[0]->rx_buffer_len and > adapter->rx_ring[0]->rx_buffer_len ? > > I am facing a problem because i have a strange requirement....i have > 2KB bufffer pools ( GFP_DMA ) in kernel. > When i receive a jumbo pkt of size 9126, five rx_desc should be > used to recieve paket. So the first rx_desc will have a status error > bit indicating that it is not > EOP ( eop ) ....I could easily keep track of my 2KB buffer pools. > > But when sending ...i wll collect all 2KB buffers of same jumbo frame > and dma to tx_ring.... > So i need 1500 on rx_ring[0]->rx_buffer_len and 9126 on > adapter->tx_ring[0]->rx_buffer_len. .Is there any way ? > > Thanks, > Ratheesh What version of the igb driver are you using? What you are describing doesn't sound like the behaviour of the current igb driver. The current igb driver does receive the frame data into 2K buffers, and transmits up to MTU size. The only limitation on the size of the frame you can transmit is the netdev->mtu which the driver doesn't evaluate. It is evaluated at the network stack level. The igb driver can send up to 9K frames, in addition it can TSO up to 64K frames and send them in 9K chunks so I am not sure what you are asking. Thanks, Alex