From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Vehent Subject: can SFQ and perturb break paquet ordering =?UTF-8?Q?=3F?= Date: Wed, 10 Mar 2010 13:22:50 +0100 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit To: Return-path: Received: from smtp3-g21.free.fr ([212.27.42.3]:37701 "EHLO smtp3-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751147Ab0CJMW7 (ORCPT ); Wed, 10 Mar 2010 07:22:59 -0500 Received: from smtp3-g21.free.fr (localhost [127.0.0.1]) by smtp3-g21.free.fr (Postfix) with ESMTP id 9A3A3818050 for ; Wed, 10 Mar 2010 13:22:53 +0100 (CET) Received: from ptichoun.linuxwall.info (ver44-2-82-242-128-240.fbx.proxad.net [82.242.128.240]) by smtp3-g21.free.fr (Postfix) with ESMTP id BBBFD818141 for ; Wed, 10 Mar 2010 13:22:50 +0100 (CET) Received: from ptichoun.linuxwall.info (localhost [127.0.0.1]) by ptichoun.linuxwall.info (Postfix) with ESMTP id 6FCD2123042 for ; Wed, 10 Mar 2010 13:22:50 +0100 (CET) Received: from njm.linuxwall.info (localhost [127.0.0.1]) by ptichoun.linuxwall.info (Postfix) with ESMTP for ; Wed, 10 Mar 2010 13:22:50 +0100 (CET) Sender: netdev-owner@vger.kernel.org List-ID: Hi netdev folks, I was digging into the sch_sfq code and I was wondering the following (I assume it's nothing new, I'm just trying to get it right): Let's consider one UDP connection that has two packets. Packet#1 goes to bucket#1, then perturb modifies the hashing algorithms and thus Packet#2 goes to bucket#800. If the round robin was positionned after bucket#1 but before bucket#800 when perturb occured, then Packet#2 will be sent before Packet#1. And since UDP can't reordered, it will be processed before on the received end. Am I getting this right or is there something in the code that I missed ? Thanks for your help. Julien Vehent