[Cerowrt-devel] [Bloat] Comcast upped service levels -> WNDR3800 can't cope...

Dave Taht dave.taht at gmail.com
Wed Sep 3 15:30:42 EDT 2014

On Wed, Sep 3, 2014 at 12:22 PM, Sebastian Moeller <moeller0 at gmx.de> wrote:
> Hi Aaron,
> On Sep 3, 2014, at 17:12 , Aaron Wood <woody77 at gmail.com> wrote:
>> On Wed, Sep 3, 2014 at 4:08 AM, Jonathan Morton <chromatix99 at gmail.com> wrote:
>> Given that the CPU load is confirmed as high, the pcap probably isn't as useful.  The rest would be interesting to look at.
>> Are you able to test with smaller packet sizes?  That might help to isolate packet-throughput (ie. connection tracking) versus byte-throughput problems.
>>  - Jonathan Morton
>> Doing another test setup will take a few days (maybe not until the weekend).  But I can get the data uploaded, and do some preliminary crunching on it.
>         So the current SQM system allows to shape on multiple interfaces, so you could set up the shaper on se00 and test between sw10 and se00 (should work if you reliably get fast enough wifi connection, something like combined shaped bandwidth <= 70% of wifi rate should work). That would avoid the whole firewall and connection tracking logic.
>         My home wifi environment is quite variable/noisy and not well-suited for this test: with rrul_be I got stuck at around 70Mbps combined bandwidth, with different distributions of the up and down-leg for no-shaping, shaping to 50Mbps10Mbps, and shaping to 100Mbps50Mbps. SIRQ got pretty much pegged at 96-99% during all netperf-wrapper runs, so I assume this to be the bottleneck (the radio was in the > 200mbps range during the test with occasional drops to 150mbps). So my conclusion would: be it really is the shaping that is limited on my wndr3700v2 with cerowrt 3.10.50-1, again if I would be confident about the measurement which I am not (but EOUTOFTIME). That or my rf environment might only allow for roughly 70-80Mbps combined throughput. For what it is worth: test where performed between macbook running macosx 10.9.4 and hp proliant n54l running 64bit openSuse 13.1, kernel 3.11.10-17 (AMD turion with tg3 gbit ethernet adapter (BQL enabled), running fq_codel on eth0), with sha
>  ping on the se00 interface.

A note on wifi throughput. CeroWrt routes, rather than bridges,
between interfaces. So I would expect for simple benchmarks, openwrt
(which bridges) might show much better wifi<-> ethernet behavior.

We route, rather than bridge wifi, because of 1) it made it easier to
debug it, and 2) the theory that multicast on busier networks messes
up wifi far more than not-bridging slows it down. Have not accumulated
a lot of proof of this, but this
was kind of enlightening:

I note that my regular benchmarking environment has mostly been 2 or
more routers with nat and firewalling disabled.

Given the trend towards looking at iptables and nat overhead on this
thread, an ipv6 benchmark on this box might be revealing.

> Best Regards
>         Sebastian
>> -Aaron
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Dave Täht


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