From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Kuznetsov Subject: Re: [RFC][PATCH] QoS TBF and latency configuration misbehavior Date: Wed, 1 Sep 2010 02:34:02 +0400 Message-ID: <20100831223402.GA7101@ms2.inr.ac.ru> References: <20100831210101.3c059a91@leibniz> <4C7D5EBD.103@gmail.com> <20100831214808.GA32141@ms2.inr.ac.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jarek Poplawski , netdev@vger.kernel.org, Stephen Hemminger To: Dan Kruchinin Return-path: Received: from minus.inr.ac.ru ([194.67.69.97]:58932 "HELO ms2.inr.ac.ru" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S1753129Ab0HaWeT (ORCPT ); Tue, 31 Aug 2010 18:34:19 -0400 Content-Disposition: inline In-Reply-To: <20100831214808.GA32141@ms2.inr.ac.ru> Sender: netdev-owner@vger.kernel.org List-ID: Hello! Hmm. Seems, you are right and I was wrong all these years. Somehow, I did wrong calculation once and this rustied to the brains. After some thinking the calulation is obviously wrong: no matter what, in steady state tbf queue is processed with rate R. What a stupid mistake... :-) Please, also think how to fix the second part of calculation which deals with peak rate. IMHO (for now :-)) it does not even contribute to latency and should be deleted. To Jarek: about the scripts. I do not think something will be broken by fixing this error. Eventually, if someone used "latency", he meant something about real latency. And even if the value was generated using the same wrong logic as tc did, using correct formula would just increase limit setting. Alexey