dummynet dropping too many packets

[rihad]

Julian Elischer wrote:
> rihad wrote:
>> Luigi Rizzo wrote:
>>> 2. your test with 'ipfw allow ip from any to any' does not
>>>    prove that the interface queue is not saturating, because
>>>    you also remove the burstiness that dummynet introduces,
>>>    and so the queue is driven differently.
>>>
>>
>> How do I investigate and fix this burstiness issue?
> 
> higher Hz rate?
> 

Rebooted with HZ=2000 10 minutes ago. Due to application design the ipfw 
  table (pipe tablearg) was flushed, so there are now 350 (and 
increasing at a rate 1 per 1-2 seconds as I type this) or so users in 
the table, and not 4k as normally would be. The box is servicing 450+ 
mbit/s without a single drop. I want to monitor how things change once 
the number of users in ipfw tables gradually increases up to several 
thousands.