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From: rihad <rihad@mail.ru>
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To: Eugene Grosbein <eugen@kuzbass.ru>
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Cc: freebsd-net@freebsd.org
Subject: Re: dummynet dropping too many packets
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Eugene Grosbein wrote:
> On Mon, Oct 05, 2009 at 02:28:58PM +0500, rihad wrote:
> 
>> Still not sure why increasing queue size as high as I want doesn't 
>> completely eliminate drops.
> 
> The goal is to make sources of traffic to slow down, this is the only
> way to descrease drops - any finite queue may be overhelmed with traffic.
> Taildrop does not really help with this. GRED does much better.
> 

Alright, so I changed to gred by adding to each config command:
ipfw ... gred 0.002/900/1000/0.1 queue 1000
and reconfigured. Still around 300-400 drops per second, which was 
typical at this load level before with taildrop anyway. There are around 
3-5 mbit/s being wasted according to systat -ifstat.

Should I now increase slots to 5-10-20k?
Very strange.

"ipfw pipe show" correctly shows that gred is at work. For example:
00512: 512.000 Kbit/s    0 ms  1000 sl. 79 queues (64 buckets)
           GRED w_q 0.001999 min_th 900 max_th 1000 max_p 0.099991
     mask: 0x00 0x00000000/0x0000 -> 0xffffffff/0x0000
...