Re: [Cerowrt-devel] cerowrt 3.3.8-17 is released

[William Katsak <wkatsak@gmail.com>]

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I agree with this assessment as far as behavior goes.  With my recent
experimentation on a Russian DSL line, I was seeing ~1200ms of uplink
buffer reported (Netalyzr) natively, but as soon as I got the AQM
running properly,
that went away completely.

Bill

Sent from my iPhone

On Aug 15, 2012, at 6:53 PM, "dpreed@reed.com" <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 don't think this is good news that you are reproting.



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.





-----Original Message-----
From: "Sebastian Moeller" <moeller0@gmx.de>
Sent: Wednesday, August 15, 2012 1:23pm
To: "Dave Taht" <dave.taht@gmail.com>
Cc: cerowrt-devel@lists.bufferbloat.net
Subject: Re: [Cerowrt-devel] cerowrt 3.3.8-17 is released

 Hi Dave,

great work, as always I upgraded my production router to the latest and
greatest (since I only have one router…). And it works quite well for
normal usage…
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...

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…).
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
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



best regards
sebastian

On Aug 12, 2012, at 11:08 PM, Dave Taht wrote:

> 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.
>
> http://huchra.bufferbloat.net/~cero1/3.3/3.3.8-17/
>
> 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.
>
> Go forth and break things!
>
> In other news:
>
> 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.
>
>
http://recordings.conf.meetecho.com/Recordings/watch.jsp?recording=IETF84_TSVAREA&chapter=part_3
>
> Far more interesting than this email!
>
>
> --
> Dave Täht
> 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

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