[Cerowrt-devel] advanced charting of realtime response under load

Dave Taht dave.taht at gmail.com
Mon Nov 5 01:29:50 EST 2012

I've been working with Toke Høiland-Jørgensen for the past few days on
trying to come up with useful plots of more complex workloads than we
currently have, in particular trying to come up with something that
would test over longer RTTs, against multiple packet classifications.
A start is at:

apt-get install python-matplotlib
build and install netperf-2.6 if you don't have it
git clone git://github.com/tohojo/netperf-wrapper.git
cd netperf-wrapper

python netperf-wrapper.py -o rrul.ps -f plot rrul

The rrul test is the nastiest one I've been able to devise...

Please note that "rrul" presently talks to a netperf netserver in
redwood city, california, and if you can find/setup a closer
netserver, the results will be less noisy and possibly more
interesting. You can override the test server on the command line. I'd
love to get some graphs back from y'all with simple_qos on and off,
and over wifi and ethernet.

(before my talk on thursday)?

Testing THROUGH the router is more useful than testing TO the router,
so setting up netperf's netserver on another box close by is more

There are a bunch of other tests in the test dir that are less extreme
than this one. For example time_ping_tcp_stream closely resembles the
classic bufferbloat tests...



Note that most of the non-rrul tests are not set to run long enough to
get useful results at longer rtts. I'd run them for 60 seconds or

PS I'd like to get to where we had an avg line on the bandwidth graph,
and a CDF plot of "ping" times, in the long run...


IF you have a 3800 router, you have sufficient memory to run
sufficient copies of netserver on it if you modify /etc/xinetd.conf to
allow for 16 instances. More performant is to disable netserver in
/etc/xinet.d/netserver, then killall -1 xinetd, and then run netserver

Dave Täht

Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html

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