From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: Packet timestamps (was: Re: Network performance degradation from 2.6.11.12 to 2.6.16.20) Date: Tue, 6 Mar 2007 16:16:24 +0100 Message-ID: <200703061616.24959.dada1@cosmosbay.com> References: <200609181850.22851.ak@suse.de> <200703061538.45049.dada1@cosmosbay.com> <20070306144315.GA9036@tentacle.sectorb.msk.ru> Mime-Version: 1.0 Content-Type: text/plain; charset="koi8-r" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Andi Kleen , Alexey Kuznetsov , David Miller , hawk@diku.dk, harry@atmos.washington.edu, linux-kernel@vger.kernel.org, Rick Jones To: "Vladimir B. Savkin" Return-path: Received: from pfx2.jmh.fr ([194.153.89.55]:40195 "EHLO pfx2.jmh.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965158AbXCFPQ1 (ORCPT ); Tue, 6 Mar 2007 10:16:27 -0500 In-Reply-To: <20070306144315.GA9036@tentacle.sectorb.msk.ru> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tuesday 06 March 2007 15:43, Vladimir B. Savkin wrote: > On Tue, Mar 06, 2007 at 03:38:44PM +0100, Eric Dumazet wrote: > > 2) "accurate_timestamps" is misleading. > > Should be "disable_timestamps" > > Not, if default is 1, as in my patch. Yes I saw this. I should write more words next time :) Full explanation: ---------------------- If your tunable is named "accurate_timestamps" then a 0 value would mean : Use a low precision timestamp (based on xtime for example) instead of a full resolution... This is not what your patch does (while it could do that, but beware that net-2.6.22 includes now a ktime_t timestamping) So : ------ It would be better to name the tunable "disable_timestamps", default 0 of course.... It would better describe what your patch is actually doing : Even if a tcpdump is running (so asking for timestamps), it wont have them because the sysctl disabled them. Thank you