From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: Getting physical packet counts with LRO enabled with ixgbe? Date: Wed, 23 Sep 2009 11:56:04 -0700 Message-ID: <4ABA6F44.4000702@candelatech.com> References: <4ABA4F8B.6040504@candelatech.com> <1253730766.2538.28.camel@localhost.localdomain> <4ABA6D0D.8010200@candelatech.com> <1253731834.2538.32.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: NetDev To: Peter P Waskiewicz Jr Return-path: Received: from mail.candelatech.com ([208.74.158.172]:57782 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751403AbZIWS4B (ORCPT ); Wed, 23 Sep 2009 14:56:01 -0400 In-Reply-To: <1253731834.2538.32.camel@localhost.localdomain> Sender: netdev-owner@vger.kernel.org List-ID: On 09/23/2009 11:50 AM, Peter P Waskiewicz Jr wrote: >> That's a bummer. I'm guessing you might get close to right on average with some >> trivial math, but if someone is sending you pkts with size of 1000 and >> your MTU is 1500, would there be any way to tell that the pkts were originally >> 1000 bytes instead of 1500? > > Good point. > >> Next time you guys re-compile your hardware, please consider adding byte counters :) > > On 10G adapters, byte counters can skyrocket quickly, so we'd need to > read them often to avoid them wrapping. But I will forward your request > to our HW design folks and see if they have other ideas to implement > these counters and make them efficient. It still takes a while to wrap 64-bit counters :) But, you do have to read every 3 secs or so if you're using 32-bit counters. This can be dealt with in user-space easily enough as long as polling the NIC for counters is efficient. Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com