[9fans] ethernet queuing question

[9fans] ethernet queuing question

[erik quanstrom]

suppose you have x bytes of memory to devote
to ethernet controller buffers.  (ether in preallocated
buffers or the main Pool.)  and suppose you're
running an ip stack on this controller.  is there any way
to insure that
	qlen(ether->iq) + sum for all Conv
		qlen(conv->iq) < f*x
for f <= 1.

the reason for the question is that i've noticed that
even for a reasonable number of users, it's pretty easy
to starve the ethernet controller or panic cause there's
no kernel memory to allocate.  (raise your hand if you've
seen the i82563 no buffers message.)  i've recently doubled
the number of buffers, halved the ethernet queue size,
and taken other steps, but more users has already overrun
this gain.

- erik