From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [net-next-2.6 PATCH 3/4] igb: Record host memory receive overflow in net_stats Date: Tue, 26 May 2009 20:36:24 -0700 (PDT) Message-ID: <20090526.203624.32809185.davem@davemloft.net> References: <20090526234958.28231.16894.stgit@localhost.localdomain> <20090526235048.28231.66889.stgit@localhost.localdomain> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, hawk@comx.dk To: jeffrey.t.kirsher@intel.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:48862 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753452AbZE0DgZ (ORCPT ); Tue, 26 May 2009 23:36:25 -0400 In-Reply-To: <20090526235048.28231.66889.stgit@localhost.localdomain> Sender: netdev-owner@vger.kernel.org List-ID: From: Jeff Kirsher Date: Tue, 26 May 2009 16:50:48 -0700 > Based on previous patch from Jesper Dangaard Brouer. > > The RNBC (Receive No Buffers Count) register for the 82576, indicate > that frames were received when there were no available buffers in host > memory to store those frames (receive descriptor head and tail > pointers were equal). The packet is still received by the NIC if > there is space in the FIFO on the NIC. > > As the RNBC value is not a packet drop, the driver stores this value > in net_stats.rx_fifo_errors to indicate that there were no system > buffers available for the incoming packet. Actual dropped packets > are counted in the MPC value. > > Saving the stats in dev->net_stats makes it visible via > /proc/net/dev as "fifo", and thus viewable to ifconfig > as "overruns" and 'netstat -i' as "RX-OVR". > > The Receive No Buffers Count (RNBC) can already be queried by > ethtool -S as "rx_no_buffer_count". > > Signed-off-by: Jeff Kirsher Applied.