[Cake] linksys ac1200 network bug

[Dave Taht]

On Sat, Nov 28, 2015 at 10:19 PM, Imre Kaloz <kaloz at openwrt.org> wrote:
> Did you see https://lkml.org/lkml/2015/11/27/325 ? I'll try to find time to
> integrate a newer kernel and that patchset as well as
> https://lkml.org/lkml/2015/11/22/9 ,
> http://lkml.iu.edu/hypermail/linux/kernel/1511.0/04354.html and
> http://lists.openwall.net/netdev/2015/09/25/151

Nope, missed those. Thx!

At one level I hate it when I test something that is out of date, but
losing a day of testing to only being a day out of date, is
particularly annoying. :(

As I noted, I'm in love with those routing cache lookup fixes in
4.x.... I have a (bad) patch for BQL for this driver too that could
probably be fixed unless it landed already? (I am not sure how you do
xmit_more without BQL)

I will go back to testing on 4.1 on the archer for a while. The steps
to reproduce the bug I saw is merely try running two or more copies of
netperf to the router.

>
>
> Imre
>
>
> On Sat, 28 Nov 2015 15:41:17 +0100, Dave Taht <dave.taht at gmail.com> wrote:
>
>> I went for a test drive of openwrt DESIGNATED DRIVER (Bleeding Edge,
>> r47665) today.
>>
>> A) I bricked the archer c7 v2. No idea why.
>>
>> B) I got a sorta working linksys 1200ac build.
>>
>> The bad news: Any attempt to run 2 or more copies of netperf's
>> netserver on the 1200ac router with the default qdiscs (mq +
>> fq_codel), at line (gbit) rate, result in it locking up *for any other
>> traffic, including ping* until the first netperf is more or less
>> complete. I fear the underlying driver is  frightfully overbuffered,
>> or has another problem.
>>
>> http://snapon.cs.kau.se/~d/archer-c7/onenetperflockout.png
>>
>> (needs BQL, too)
>>
>> The still bad news: cake works in both directions for a while longer,
>> then goes boom similarly.
>>
>> The somewhat good news:
>>
>> cake "shaped" to 900mbit on inbound and outbound to the router - does
>> not lock up the router. It merely runs out of cpu, but still does
>> manage quite respectable throughput in both  directions while doing
>> so. Note, I did not say "latency".
>>
>> http://snapon.cs.kau.se/~d/archer-c7/encouraged.png
>>
>> As usual there is some flent data in that dir if you want to draw your
>> own plots.
>>
>> I was not in a position to actually test traffic through the router
>> (because I had the archer setup to do that)
>>
>> I wouldn't draw any conclusions from this. Well, a safe conclusion,
>> is: don't install this build.
>>
>> On Sat, Nov 28, 2015 at 11:41 AM, Dave Taht <dave.taht at gmail.com> wrote:
>>>
>>> Trying to do my first openwrt build in a while.
>>>
>>> make[5]: Leaving directory
>>>
>>> '/home/cero4/src/archer-c7/build_dir/target-mips_34kc_musl-1.1.11/dante-1.2.2'
>>> Makefile:349: recipe for target 'all' failed
>>>
>>> I checked: the package "dante" is not installed. Nor can I figure out
>>> what package is arbitrarily requiring it.
>>>
>>> I truly am in hell.
>>
>>
>> Simple patch for this, It involves invoking a deity.
>>
>>
>>> Dave Täht
>>> Let's go make home routers and wifi faster! With better software!
>>> https://www.gofundme.com/savewifi