[Cerowrt-devel] performance numbers from WRT1200AC (Re: Latest build test - new sqm-scripts seem to work; "cake overhead 40" didn't)

Aaron Wood woody77 at gmail.com
Wed Jun 24 21:53:52 EDT 2015

Here's a long-range (indoors) test result with the 1900AC.  I have about
9dB snr at the client (all the way across my house, which has plaster


download buffering is the 1900ac, upload buffering is the mac laptop's
driver.  Both are trying too hard to deliver those packets, I think.

The driver has crazy over-buffering in the face of poor signal conditions.
OTOH, I'm amazed at the throughput numbers.  But this is an 80Mhz wide 5Ghz
channel, in a quiet environment, so it has LOTS of airspace to work in.


On Wed, Jun 24, 2015 at 9:32 AM, Dave Taht <dave.taht at gmail.com> wrote:

> On Wed, Jun 24, 2015 at 4:31 AM, Mikael Abrahamsson <swmike at swm.pp.se>
> wrote:
> > On Tue, 23 Jun 2015, Sebastian Moeller wrote:
> >
> >> As Dave said it would be nice see RRUL data from the same testbed. It
> >> would be so nice if flint had a way to send different sized TCP
> packets… (I
> >> guess this might be faked with MSS clamping in the router and relaying
> on
> >> path MTU discovery?)
> >
> >
> > What kind of tests should I run? I have rrul results now, both at the
> same
> > time as running iperf3. I set iperf3 to run with 10 parallel streams,
> > different MSS per test, and let it run for 30 seconds into the rrul
> test. So
> > in all the tests, iperf3 session stops running half way into the rrul
> test.
> >
> > I set sqm to 500M up and down on eth0, ECN up and down, and not to squash
> > DSCP in any direction.
> >
> > http://swm.pp.se/aqm/rrul-wrt1200ac-150624.pdf
> 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.
> > Tell me if there is more information I can provide or tests to run.
> 0) I tend to have a script for everything... I can give you an example
> script in another email.
> 1) tc -s qdisc show dev whatever # will show actuall drop/mark statistics
> 2) Please run your flent tests with -x --disable-log
> -x collects more metadata, --disable-log disables the automatic log
> scaling which is so hard to discern on these plots.
> Use -t "title" to differentiate between variables under test.
> 3) I also tend to use flent's --remote-metadata=root at 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.
> 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.
> 5) try disabling offloads on all interfaces on the router (or running cake)
> My usual suite of tests is rrul, rrul_be, tcp_1up, tcp_1down, and
> tcp_2up_delay.
> and rtt_fair (if you have more than one target server available)...
> all without the iperf stuff....
> Your mss changing idea is interesting, and I would like to do a mod to
> tcp_2up_delay to sort of match your iperf combination + flent to
> totally capture all data.
> 6) I am pretty interested as to what happens *without* sqm at the max
> forwarding rate with fq_codel engaged on all these tests.
> >
> > --
> > Mikael Abrahamsson    email: swmike at swm.pp.se
> >
> > _______________________________________________
> > Cerowrt-devel mailing list
> > Cerowrt-devel at lists.bufferbloat.net
> > https://lists.bufferbloat.net/listinfo/cerowrt-devel
> >
> --
> Dave Täht
> worldwide bufferbloat report:
> http://www.dslreports.com/speedtest/results/bufferbloat
> And:
> What will it take to vastly improve wifi for everyone?
> https://plus.google.com/u/0/explore/makewififast
> _______________________________________________
> Cerowrt-devel mailing list
> Cerowrt-devel at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/cerowrt-devel
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