[Cake] BUG_ON vs WARN_ON

[Dave Taht]

I did test this version of cake yesterday, had no major problems, aside from:

1) it seeming not to register drops under some circumstances in the
statistics. (could be flent)

2) switching stuff like this

tc qdisc add dev eth0 root cake bandwidth 700mbit
tc qdisc replace dev eth0 root cake bandwidth 1100mbit # out of cpu,
basically, at 700 mbit
tc qdisc replace dev eth0 root cake unlimited # still stuck at 700mbit

kept the thing at 700mbits (out of cpu at that point).

tc qdisc del dev eth0 root cake
tc qdisc add dev eth0 root cake unlimited # native rate of 1gbit achieved


On Wed, Oct 5, 2016 at 8:45 AM, Kevin Darbyshire-Bryant
<kevin at darbyshire-bryant.me.uk> wrote:
>
>
> On 05/10/16 16:42, Jonathan Morton wrote:
>>
>>
>>> On 5 Oct, 2016, at 18:24, Kevin Darbyshire-Bryant
>>> <kevin at darbyshire-bryant.me.uk> wrote:
>>>
>>> How amenable are you to changing all 4 BUG_ON instances in cake to
>>> WARN_ON?
>>>
>>> Linus isn't a complete fan and I'm thinking that producing a stack
>>> trace and trying to carry on is more helpful to a remote accessed,
>>> no serial interface type device than just killing the kernel dead.
>>>
>>> Quite possibly other bad things(tm) will happen shortly after...or
>>> maybe there will be enough time look at dmesg for that stack
>>> trace.
>>
>>
>> The two in cake_heap_swap() can probably go away completely - they
>> were there to make sure the heap algorithms were working correctly.
>> They never did trigger, as it happens.
>>
>> The other two are genuine serious bugs (array overflow) if they ever
>> trigger.  It’s safer to leave them as-is.
>
>
> Fair enough :-)  I wonder what it was that caused yesterday's issues?  I
> really must try again when I've more time to get proper access.
>
> Kevin
>
>
>>
>> - Jonathan Morton
>>
> _______________________________________________
> Cake mailing list
> Cake at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/cake



-- 
Dave Täht
Let's go make home routers and wifi faster! With better software!
http://blog.cerowrt.org