dummynet dropping too many packets

[Eugene Grosbein]

Barney Cordoba wrote:

> Your problem is that at high traffic levels you need to reduce traffic 
> flows, not just delay it as dummynet does.

Dummynet does not "just adds delay".

> The entire point of traffic
> shaping is to smooth out your traffic flows; not to make it so choppy
> that you have packets sitting in a transmit queue for 1/2 millisecond
> in addition to the dummynet delays. While dummynet may not be dropping
> packets, you have packets being dropped in TCP stacks throughout your
> customer base, most likely.

If you followed the thread, you known that rihad tried GRED.
The problem was not due to exceeded bandwidth but in inadequate
interface-level FIFO queue length. And no way to adjust it without a patch.

This makes me think we should have general user interface for setting
the queue length for any network interface just like Cisco 'hold-queue' command does.
For now, only some drivers (e.g., em(4)) have such option.