Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753397Ab2KEIlv (ORCPT ); Mon, 5 Nov 2012 03:41:51 -0500 Received: from mail-pb0-f46.google.com ([209.85.160.46]:56887 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753052Ab2KEIlt (ORCPT ); Mon, 5 Nov 2012 03:41:49 -0500 MIME-Version: 1.0 In-Reply-To: <20121030072415.17199f9a@nehalam.linuxnetplumber.net> References: <20121030060056.GA3373@paolo-ThinkPad-W520> <20121030072415.17199f9a@nehalam.linuxnetplumber.net> Date: Mon, 5 Nov 2012 16:41:49 +0800 Message-ID: Subject: Re: [PATCH RFC] pkt_sched: enable QFQ to support TSO/GSO From: Cong Wang To: Stephen Hemminger Cc: Paolo Valente , jhs@mojatatu.com, David Miller , LKML , Linux Kernel Network Developers , rizzo@iet.unipi.it, fchecconi@gmail.com Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2095 Lines: 48 On Tue, Oct 30, 2012 at 10:24 PM, Stephen Hemminger wrote: > On Tue, 30 Oct 2012 07:00:56 +0100 > Paolo Valente wrote: > >> Hi, >> if the max packet size for some class (configured through tc) is >> violated by the actual size of the packets of that class, then QFQ >> would not schedule classes correctly, and the data structures >> implementing the bucket lists may get corrupted. This problem occurs >> with TSO/GSO even if the max packet size is set to the MTU, and is, >> e.g., the cause of the failure reported in [1]. Two patches have been >> proposed to solve this problem in [2], one of them is a preliminary >> version of this patch. >> >> This patch addresses the above issues by: 1) setting QFQ parameters to >> proper values for supporting TSO/GSO (in particular, setting the >> maximum possible packet size to 64KB), 2) automatically increasing the >> max packet size for a class, lmax, when a packet with a larger size >> than the current value of lmax arrives. >> >> The drawback of the first point is that the maximum weight for a class >> is now limited to 4096, which is equal to 1/16 of the maximum weight >> sum. >> >> Finally, this patch also forcibly caps the timestamps of a class if >> they are too high to be stored in the bucket list. This capping, taken >> from QFQ+ [3], handles the unfrequent case described in the comment to >> the function slot_insert. >> >> [1] http://marc.info/?l=linux-netdev&m=134968777902077&w=2 >> [2] http://marc.info/?l=linux-netdev&m=135096573507936&w=2 >> [3] http://marc.info/?l=linux-netdev&m=134902691421670&w=2 >> >> Signed-off-by: Paolo Valente >> Tested-by: Cong Wang > > Acked-by: Stephen Hemminger David, could you take this patch? Stephen acked it. Thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/