> On Aug 22, 2018, at 8:17 AM, Jonathan Morton <[email protected]> wrote:
> 
>> On 22 Aug, 2018, at 12:06 am, Pete Heist <[email protected]> wrote:
>> 
>> when fq_codel is the qdisc, the eBPF action is only called "once in a while”
> 
> One difference between fq_codel and Cake is that the former - which has no 
> shaper - will "bypass" packets when it's empty and there's no back-pressure 
> filling it.  In that case no packet classification occurs and filters will 
> not be called.  Or at least, that's how it used to be set up; I haven't 
> looked at it recently.  Cake does not rely on the same set of assumptions, so 
> will always call the filter.

Aha, that sounds likely, I’ll try with htb and a rate limit. Testing with 
fq_codel was challenging as I had to “do stuff” until my printk’s were 
eventually called, but it’s easier now that I can use cake. I suppose in my 
case fq_codel’s behavior would be ok in production, because if there’s no queue 
then there’s no need to classify. Maybe in some other cases (like gathering 
stats), it could be problematic.
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