On Fri, 2004-07-09 at 14:26, Vladimir Kondratiev wrote:
> > Who marks the skb->priority? Is that the default mark as per TOS?
> > I think the VLAN code marks it as well.
> I don't care. It should not be driver's business. Actually, it is TOS. AFAIK,
> application supposed to do setsockoption(SO_PRIORITY) on its socket so set
That or if routed from another host, then TOS does get extracted and set
> Agree about intelligence. Driver should serve link and MAC layer. But exactly
> because link layer have different priorities, driver need several Tx queues.
> It is stack's business to route packet to the proper queue. Driver should
> deliver it using appropriate MAC layer priority.
So far you have said there are two schedulers h/ware understands: strict
priority(3 band strict priority is the deafult in Linux) and WRR.
The qdisc level is already taken care of today.
> Waiting. If no support will exist, it simply means we will be unable to use
> QoS provided by modern 802.11.
I think someone with motivation and hardware (such as you
Vladimir ;->)should take the lead. I have offered to consult and review
> Depending on market development, impact may
> range from being slightly slower relating to Windows clients, to being almost
> completely unable to communicate for traffic like VOIP. Later will be the
> case if most access points will implement QoS as in TGE.
> I can now deliver packets accordingly to skb->priority, but if stack have
> different idea for what is proper proportion between different sorts of
> traffic, driver's Tx path will be flooded with low priority frames.
I dont think so - as long as you map to a specific qdisc things should
work fine. i.e the scheduling semantics will be taken good care of by
the qdisc level.
So lets separate the two levels, driver and qdisc level.
I dont think they should be synchronized. In my opinion, the
synchronization point is the configurator/operator/management s/ware of
> Situation is much worser for streams with admission control. I have no
> mechanism to communicate with stack for such traffic establishment and tear
Let me make an interim suggestion:
To illustrate i will assume 3 priorities with priority 1 higher than
priority 3. Substitute with whatever driver does. Assuming the
priorities will be reflected in the skb->priority.
- Shut down device only when highest(1) priority ring is full.
- if packets received for priority 2 and 3 and their respective rings
are full, drop the packet in the driver and return a 0 i.e dont shut
You can also do the following in the case of strict priority(caveat is
reordering may happen):
for each prio X try to stash on DMA ring of prio X. If full, try X+1, if
full try X+2 etc.