From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: inaccurate packet scheduling Date: Tue, 18 Dec 2012 10:43:50 -0800 Message-ID: <20121218104350.6aec09fd@nehalam.linuxnetplumber.net> References: <20121218150407.GB1533@minipsycho.orion> <20121218175409.GA1690@minipsycho.orion> <20121218184036.GB1690@minipsycho.orion> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Eric Dumazet , Stephen Hemminger , jhs@mojatatu.com, davem@davemloft.net, tgraf@suug.ch, netdev@vger.kernel.org To: Jiri Pirko Return-path: Received: from mail.vyatta.com ([76.74.103.46]:49124 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755448Ab2LRSpv (ORCPT ); Tue, 18 Dec 2012 13:45:51 -0500 In-Reply-To: <20121218184036.GB1690@minipsycho.orion> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 18 Dec 2012 19:40:36 +0100 Jiri Pirko wrote: > Tue, Dec 18, 2012 at 07:06:53PM CET, edumazet@google.com wrote: > >> No such messages in log > >> > >>>Also turn off TSO since it screws up any form of rate control. > >> > >> Turning off TSO did not help. However, turning off scatter-gather > >> helped, on both HP DL360G8 (igb) and IBM JS22 (ehea). > >> > > > >Think to also disable GSO > > On rhel6 kernel (2.6.32-based) I have to disable GSO as well. > > The question is: Is this a bug or is it mandatory to get this offload > disabled in order to TBF to be working correctly? > > Thanks a bunch. > > Jiri > > > > >Alternatively, you can use "mtu 65536" to allow TBF to send packets > >bigger than 2048 bytes It is really a bug. The packet schedulers mostly assume that a single skb results in a single packet, and that the skb->len equals the size of the packet on the wire.