From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: tbf/htb qdisc limitations Date: Thu, 14 Oct 2010 06:44:05 +0000 Message-ID: <20101014064404.GA6219@ff.dom.local> References: <4CB1A22B.9090701@gmail.com> <20101012101022.GA8578@ff.dom.local> <20101012215932.GA1945@del.dom.local> <4CB4DE6E.7030802@hp.com> <20101013062649.GA6915@ff.dom.local> <20101013233653.1e363692.billfink@mindspring.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Rick Jones , Steven Brudenell , netdev@vger.kernel.org To: Bill Fink Return-path: Received: from mail-bw0-f46.google.com ([209.85.214.46]:38401 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754191Ab0JNHqe (ORCPT ); Thu, 14 Oct 2010 03:46:34 -0400 Received: by bwz15 with SMTP id 15so175603bwz.19 for ; Thu, 14 Oct 2010 00:46:33 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20101013233653.1e363692.billfink@mindspring.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Oct 13, 2010 at 11:36:53PM -0400, Bill Fink wrote: > On Wed, 13 Oct 2010, Jarek Poplawski wrote: > > > On Tue, Oct 12, 2010 at 03:17:18PM -0700, Rick Jones wrote: > > >>> my burst problem is the only semi-legitimate motivation i can think > > >>> of. the only other possible motivations i can imagine are setting > > >>> "limit" to buffer more than 4GB of packets and setting "rate" to > > >>> something more than 32 gigabit; both of these seem kind of dubious. is > > >>> there something else you had in mind? > > >> > > >> > > >> No, mainly 10 gigabit rates and additionally 64-bit stats. > > > > > > Any issue for bonded 10 GbE interfaces? Now that the IEEE have ratified > > > (June) how far out are 40 GbE interfaces? Or 100 GbE for that matter. > > > > Alas packet schedulers using rate tables are still around 1G. Above 2G > > they get less and less accurate, so hfsc is recommended. > > I was just trying to do an 8 Gbps rate limit on a 10-GigE path, > and couldn't get it to work with either htb or tbf. Are you > saying this currently isn't possible? Let's start from reminding that no precise packet scheduling should be expected with gso/tso etc. turned on. I don't know current hardware limits for such a non-gso traffic, but for 8 Gbit rate htb or tbf would definitely have wrong rate tables (overflowed values) for packet sizes below 1500 bytes. > Or are you saying to use > this hfsc mechanism, which there doesn't seem to be a man page > for? There was a try: http://lists.openwall.net/netdev/2009/02/26/138 Jarek P.