Hi Vladimir, On Tue, Apr 20, 2021 at 16:27:10AM +0800, Vladimir Oltean wrote: > > On Tue, Apr 20, 2021 at 03:06:40AM +0000, Xiaoliang Yang wrote: >> Hi Vladimir. >> >> On Mon, Apr 19, 2021 at 20:38PM +0800, Vladimir Oltean wrote: >> > >> >What is a scheduled queue? When time-aware scheduling is enabled on >> >the port, why are some queues scheduled and some not? >> >> The felix vsc9959 device can set SCH_TRAFFIC_QUEUES field bits to >> define which queue is scheduled. Only the set queues serves schedule >> traffic. In this driver we set all 8 queues to be scheduled in >> default, so all the traffic are schedule queues to schedule queue. > > I understand this, what I don't really understand is the distinction that the > switch makes between 'scheduled' and 'non-scheduled' traffic. > What else does this distinction affect, apart from the guard bands added > implicitly here? The tc-taprio qdisc has no notion of 'scheduled' > queues, all queues are 'scheduled'. Do we ever need to set the scheduled > queues mask to something other than 0xff? If so, when and why?
Yes, it seems only affect the guard band. If disabling always guard band bit, we can use SCH_TRAFFIC_QUEUES to determine which queue is non-scheduled queue. Only the non-scheduled queue traffic will reserve the guard band. But tc-taprio qdisc cannot set scheduled or non-scheduled queue now. Adding this feature can be discussed in future. It is not reasonable to add guardband in each queue traffic in default, so I disable the always guard band bit for TAS config. Thanks, Xiaoliang Yang
