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

[Aaron Wood <woody77@gmail.com>]

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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
walls):

http://www.dslreports.com/speedtest/737736

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.

-Aaron

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

> On Wed, Jun 24, 2015 at 4:31 AM, Mikael Abrahamsson <swmike@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@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@swm.pp.se
> >
> > _______________________________________________
> > Cerowrt-devel mailing list
> > Cerowrt-devel@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@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/cerowrt-devel
>

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