dummynet dropping too many packets

[Luigi Rizzo]

On Mon, Oct 05, 2009 at 03:52:39PM +0500, rihad wrote:
> 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
> ...

you keep omitting the important info i.e. whether individual
pipes have drops, significant queue lenghts and so on.

i am giving up!