From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: UDP is bypassing qdisc statistics .... Date: Tue, 01 Sep 2009 09:00:46 +0200 Message-ID: <4A9CC69E.9090308@gmail.com> References: <20090901063726.GA5222@ff.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Mark Smith , Christoph Lameter , netdev@vger.kernel.org, davem@linux-foundation.org To: Jarek Poplawski Return-path: Received: from gw1.cosmosbay.com ([212.99.114.194]:49223 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752829AbZIAHBV (ORCPT ); Tue, 1 Sep 2009 03:01:21 -0400 In-Reply-To: <20090901063726.GA5222@ff.dom.local> Sender: netdev-owner@vger.kernel.org List-ID: Jarek Poplawski a =E9crit : > On 31-08-2009 22:58, Mark Smith wrote: >> On Mon, 31 Aug 2009 21:54:49 +0200 >> Eric Dumazet wrote: >> >>> Christoph Lameter a =E9crit : >>>> This is with 2.6.31-rc7. If I send icmp then its correctly registe= red as a >>>> packet by the qdisc layer: >>>> >> >>> loopback device do bypass qdisc layer for example... >> On occassion, I'd have found it useful if it didn't. It'd be conveni= ent >> to test out your qdisc config, or test out applications performance >> behaviour over a simulated WAN via netem, without having to a >> network and two hosts, and all the related miscellaneous setup work. >=20 > Probably Eric and you mean something special, but generally a loopbac= k > and some other virtuals bypass qdisc layer only with default qdisc. >=20 Yes, I was referring to Christoph use, since on its machine, only output from "tc -s -d qdisc" is about eth0 Mark, you can certainly do something like # tc qdisc del dev lo root # tc qdisc add dev lo root netem delay 100ms 10ms # ping 127.0.0.1 PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data. 2009/08/01 08:59:22.799 64 bytes from 127.0.0.1: icmp_seq=3D1 ttl=3D64 = time=3D204 ms 2009/08/01 08:59:23.804 64 bytes from 127.0.0.1: icmp_seq=3D2 ttl=3D64 = time=3D208 ms 2009/08/01 08:59:24.801 64 bytes from 127.0.0.1: icmp_seq=3D3 ttl=3D64 = time=3D204 ms 2009/08/01 08:59:25.808 64 bytes from 127.0.0.1: icmp_seq=3D4 ttl=3D64 = time=3D209 ms # tc -s -d qdisc show dev lo qdisc netem 8001: root limit 1000 delay 100.0ms 10.0ms Sent 1764 bytes 18 pkt (dropped 0, overlimits 0 requeues 0) rate 0bit 0pps backlog 0b 0p requeues 0