[altq 706] Re: ALTQ inbound processing

[Kenjiro Cho <kjc@csl.sony.co.jp>]

Lars Eggert wrote:
> > The problem is that input queues are empty most of the time so that
> > there isn't much to do with queueing.
> 
> I agree with you that for a router, this is not an issue. However, I'm using
> ALTQ on the end hosts, as part of a larger system.
> 
> Please let me give you a little more background information, so you know why
> I'm interested in this, and why I think for my scenario input queue control
> makes sense. The big picture is that I'm developing (host) OS extensions to
> allow background use of any idle resources in the system. One example is the
> CPU, for which POSIX idle-time scheduling (hard priorities, possibly
> infinite preemption) basically gets me most of the way there.

OK, then I think it isn't too hard to use "struct ifaltq" for input
queues.

The main problem of input queueing implementation is how to trigger
"dequeue" for low priority queues.  (for output queues, tx complete
interrupts trigger dequeueing.) 
With only 2 queues (foreground and background), your approach seems to
be straightforward.

-Kenjiro