On Wed, 24 Jun 2015, Dave Taht wrote:
From what I see here you are rarely, if ever, engaging fq_codel
properly. Latencies are pretty high. In particular, I would suspect
you are hitting offloads hard, and the current (fixed in linux 4.1)
codel drop algorithm stops dropping below "maxpacket", which was meant
in the ns2 code to be a MTU, but in the linux code ended up being a
TSO sized (64k!) packet.
tc -s qdisc show # will show the maxpacket.
http://swm.pp.se/aqm/qdisc-show.txt
I discovered also that I wasn't running ECN, I had set tcp_ecn = 2 on the
linux box. All the tests done in
http://swm.pp.se/aqm/flent-mikabr-150625-1.tar are now done with ECN
working, without iperf3 running, and with and without SQM, but with
default offload setting.
Also, now iperf3 says "0 packet lost" when I use that.
2) Please run your flent tests with -x --disable-log
Done.
Use -t "title" to differentiate between variables under test.
Done.
3) I also tend to use flent's --remote-metadata=root@your_openwrtbox
to get the stats on that box into the metadata. You have to add your
local .ssh/id_rsa.pub key to
your_openwrtbox:/etc/dropbear/authorized_keys file to do this.
Done.
4) With all that in hand, sticking up a tarball of the results makes
for easy plotting of various other graphs, and using the flent-gui,
you can combine results from each run easily, also.
See above.
5) try disabling offloads on all interfaces on the router (or running cake)
This is my next thing to test, I have some other things I need to try
first.
My usual suite of tests is rrul, rrul_be, tcp_1up, tcp_1down, and tcp_2up_delay.
Done.
and rtt_fair (if you have more than one target server available)...
all without the iperf stuff....
I do not have another machine readily available here at home.
6) I am pretty interested as to what happens *without* sqm at the max
forwarding rate with fq_codel engaged on all these tests.
This is included. Why did you want to do this test? Just to see if the
WRT1200AC can do wirespeed forwarding with fq_codel on? Because with the
setup I have, I don't see how there can be any buffering going on because
it's a single gig port both in and out.
--
Mikael Abrahamsson email: [email protected]
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