From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v2] l2tp: use per-cpu variables for u64_stats updates Date: Wed, 27 Jun 2012 15:21:53 -0700 (PDT) Message-ID: <20120627.152153.75362722222316911.davem@davemloft.net> References: <1340823810.26242.81.camel@edumazet-glaptop> <4FEB6B64.5060708@hp.com> <1340829541.26242.90.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: rick.jones2@hp.com, tparkin@katalix.com, netdev@vger.kernel.org, David.Laight@ACULAB.COM, jchapman@katalix.com To: eric.dumazet@gmail.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:47603 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753768Ab2F0WVy (ORCPT ); Wed, 27 Jun 2012 18:21:54 -0400 In-Reply-To: <1340829541.26242.90.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet Date: Wed, 27 Jun 2012 22:39:01 +0200 > In 2012 or 2013, 64bits kernels are the norm, and 32bit the exception. > > Should we add complex code to l2tp just for being able to run it on > 32bit kernels with 64bit stats ? > > Considering this code is buggy at the v1 & v2, I am really wondering. > > All sane SNMP applications are ready to cope with 32bits counters > wrapping. > > Machines that could wrap the 32bit counter several times per second are > probably running on 64bit kernels. > > Also percpu stats are overkill unless a device is really meant to be > used in // by many cpus. I agree with Eric on all counts.