From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] codel: refine one condition to avoid a nul rec_inv_sqrt Date: Fri, 10 Aug 2012 16:54:05 -0700 (PDT) Message-ID: <20120810.165405.284352377586092244.davem@davemloft.net> References: <1343631141.2626.13293.camel@edumazet-glaptop> <20120730.145412.1689803770003231369.davem@davemloft.net> <1344611771.31104.2716.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, lp2s1h@gmail.com To: eric.dumazet@gmail.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:46740 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760187Ab2HJXyF (ORCPT ); Fri, 10 Aug 2012 19:54:05 -0400 In-Reply-To: <1344611771.31104.2716.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet Date: Fri, 10 Aug 2012 17:16:11 +0200 > On Mon, 2012-07-30 at 14:54 -0700, David Miller wrote: >> From: Eric Dumazet >> Date: Mon, 30 Jul 2012 08:52:21 +0200 >> >> > From: Eric Dumazet >> > >> > One condition before codel_Newton_step() was not good if >> > we never left the dropping state for a flow. As a result >> > rec_inv_sqrt was 0, instead of the ~0 initial value. >> > >> > codel control law was then set to a very aggressive mode, dropping >> > many packets before reaching 'target' and recovering from this problem. >> > >> > To keep codel_vars_init() as efficient as possible, refine >> > the condition to make sure rec_inv_sqrt initial value is correct >> > >> > Many thanks to Anton Mich for discovering the issue and suggesting >> > a fix. >> > >> > Reported-by: Anton Mich >> > Signed-off-by: Eric Dumazet >> >> Applied and queued up for -stable. > > Hi David, I think this patch got lost somehow ? Thanks for catching this, I've corrected it now.