Cohen, Guy wrote: > Patrick McHardy wrote: > >>jamal wrote: >> >>>Sure - but what is wrong with that? >> >> >>Nothing, this was just to illustrate why I disagree with the > > assumption > >>that the packet has hit the wire. On second thought I do agree with > > your > >>assumption for the single HW queue case, at the point we hand the > > packet > >>to the HW the packet order is determined and is unchangeable. But this >>is not the case if the hardware includes its own scheduler. The qdisc >>is simply not fully in charge anymore. > > > For WiFi devices the HW often implements the scheduling, especially when > QoS (WMM/11e/11n) is implemented. There are few traffic queues defined > by the specs and the selection of the next queue to transmit a packet > from, is determined in real time, just when there is a tx opportunity. > This cannot be predicted in advance since it depends on the medium usage > of other stations. > > Hence, to make it possible for wireless devices to use the qdisc > mechanism properly, the HW queues should _ALL_ be non-empty at all > times, whenever data is available in the upper layers. Or in other > words, the upper layers should not block a specific queue because of the > usage of any other queue.
Thats exactly what I'm saying. And its not possible with a single queue state as I tried to explain in my last last. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
