From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout-de.gmx.net (mailout-de.gmx.net [213.165.64.23]) by huchra.bufferbloat.net (Postfix) with SMTP id CD4CD21F0B6 for ; Wed, 15 Aug 2012 21:51:21 -0700 (PDT) Received: (qmail invoked by alias); 16 Aug 2012 04:51:19 -0000 Received: from unknown (EHLO dhcp-112.home.lan) [75.142.58.156] by mail.gmx.net (mp035) with SMTP; 16 Aug 2012 06:51:19 +0200 X-Authenticated: #24211782 X-Provags-ID: V01U2FsdGVkX19nLI9rEipnMMATdKGukTBv2egaT9doTOGtTHiseR muhIapMKhzJVWA Mime-Version: 1.0 (Apple Message framework v1278) Content-Type: text/plain; charset=windows-1252 From: Sebastian Moeller X-Priority: 3 (Normal) In-Reply-To: <1345071222.04317697@apps.rackspace.com> Date: Wed, 15 Aug 2012 21:51:11 -0700 Content-Transfer-Encoding: quoted-printable Message-Id: References: <36D61FDC-9AA9-46CC-ACBB-2D28B250C660@gmx.de> <1345071222.04317697@apps.rackspace.com> To: dpreed@reed.com X-Mailer: Apple Mail (2.1278) X-Y-GMX-Trusted: 0 Cc: cerowrt-devel@lists.bufferbloat.net Subject: Re: [Cerowrt-devel] cerowrt 3.3.8-17 is released X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Aug 2012 04:51:22 -0000 Hi, On Aug 15, 2012, at 3:53 PM, dpreed@reed.com wrote: > Just to clarify, the way Netalyzr attempts to measure "uplink = buffering" may not actually measure queue length. It just spews UDP = packets at the target, and measures sender-receiver packet delay at the = maximum load it can generate. So it's making certain assumptions about = the location and FIFO nature of the "bottleneck queue" when it = calculates that. I see, pretty much what I expected in regards to methodology, = even though I am not sure about the 'maximum load it can generate part'.=20= > =20 > I don't think this is good news that you are reporting. My take on this was that the 3 seconds max buffer seemed wrong, = even though the interactivity was/is right there where it should be with = codel. BTW I was following Dave's recommendation and used openwork's = default QOS instead of simple_qos.sh if that matters. > =20 > Assuming codel is measuring "sojourn time" and controlling it = properly, you should not see 2.8 *seconds* of UDP queueing delay on the = uplink - packets should be being dropped to keep that delay down to = under 10 milliseconds. > I have no idea how that jibes with low ping times, unless you are = getting the ICMP packets spoofed. My totally current pet theory (totally created with out looking = at data) is that fq_codel somehow manages to confine the over buffering = to the UDP probe flow(s) and keep my pings in unencumbered flows (that = or openwrts hfsc packet scheduler saves the interactivity=85). But as I = stated I have no data to back this up (nor am I likely to get some any = time soon). Thanks Sebastian > =20 > =20 > -----Original Message----- > From: "Sebastian Moeller" > Sent: Wednesday, August 15, 2012 1:23pm > To: "Dave Taht" > Cc: cerowrt-devel@lists.bufferbloat.net > Subject: Re: [Cerowrt-devel] cerowrt 3.3.8-17 is released >=20 > Hi Dave, >=20 > great work, as always I upgraded my production router to the latest = and greatest (since I only have one router=85). And it works quite well = for normal usage=85 > Netalyzr reports around 2800ms seconds of uplink buffering, yet = saturating the uplink does not affect ping times to a remote target = noticeably, basically the same as for all codellized ceo versions I = tested so far... >=20 > Some notes and a question: > I noticed that even given plenty of swap space (1GB on a usb stick), = using http://broadband.mpi-sws.org/residential/ to exercise UDP stress = (on the uplink I assume) I can easily produce (I run the test from a = macosx via 5GHz wireless over 1.5 yards): > Aug 15 01:16:29 nacktmulle kern.err kernel: [175395.132812] ath: = skbuff alloc of size 1926 failed > (and plenty of those=85).=20 > What then happens is that the OOM killer will aim for bind (reasonable = since it is the largest single process) and kill it. When I try to = restart bind by: > root@nacktmulle:~# /etc/rc.d/S47namedprep start > root@nacktmulle:~# /etc/rc.d/S48named restart > Stopping isc-bind > /etc/chroot/named//var/run/named/named.pid not found, trying brute = force=20 > killall: named: no process killed > Kicking isc-bind in xinetd > rndc: connect failed: 127.0.0.1#953: connection refused > And bind does not start again and the router becomes less than useful. = Now I assume I am doing something wrong, but what, if you have any idea = how to solve this short of a reboot of the router (my current method) I = would be happy to learn >=20 >=20 >=20 > best regards > sebastian >=20 > On Aug 12, 2012, at 11:08 PM, Dave Taht wrote: >=20 > > I'm too tired to write up a full set of release notes, but I've been > > testing it all day, > > and it looks better than -10 and certainly better than -11, but I = won't know > > until some more folk sit down and test it, so here it is. > >=20 > > http://huchra.bufferbloat.net/~cero1/3.3/3.3.8-17/ > >=20 > > fresh merge with openwrt, fix to a bind CVE, fixes for 6in4 and = quagga > > routing problems, > > and a few tweaks to fq_codel setup that might make voip better. > >=20 > > Go forth and break things! > >=20 > > In other news: > >=20 > > Van Jacobson gave a great talk about bufferbloat, BQL, codel, and = fq_codel > > at last week's ietf meeting. Well worth watching. At the end he = outlines > > the deployment problems in particular. > >=20 > > = http://recordings.conf.meetecho.com/Recordings/watch.jsp?recording=3DIETF8= 4_TSVAREA&chapter=3Dpart_3 > >=20 > > Far more interesting than this email! > >=20 > >=20 > > --=20 > > Dave T=E4ht > > http://www.bufferbloat.net/projects/cerowrt/wiki - "3.3.8-17 is out > > with fq_codel!" > > _______________________________________________ > > Cerowrt-devel mailing list > > Cerowrt-devel@lists.bufferbloat.net > > https://lists.bufferbloat.net/listinfo/cerowrt-devel >=20 > _______________________________________________ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel