Re: [taste-users] PolyORB-Hi message queue - Sporadic PI Buffer and Attr

Thanks both for yours answers. They are very helpful!

On 25.01.2018 17:18, Jorge Garrido Balaguer wrote:

Hi Javier,

As far as I know, a PI (Protected Interface) is that, an interface, that is required to be accessed under mutual exclusion. It does not make any assumption on the data encapsulated behind. If I understood your question correctly, from the circular buffer _expression_, you are considering it to be some kind of data structure by itself.

If your question is on which order requests are served when there are more than one, I assume it to be in FIFO order, since is the only approach that allows realtime analysis.

I was assuming there is a FIFO mechanism somehow. My question is in case the buffer is full. Does it drop the newest sample or delete the oldest from the buffer and push the newest (circular buffer)? I understand from Maxime no buffer is currently available. Nevertheless, from my perspective a circular buffer would make more sense than just a FIFO queue.

Regards,

Javier.

Related to real-time and addressing your second question, the terms you are asking about are common in the field:

* Min Inter-arrival time is the minimum time expected between calls to the interface.

* Deadline is the maximum time that is allow to span between the interface is called and the call has been completely served. Note that may include time in which the caller is not actually executing due to being preempted from the processor.

* WCET stands for Worst Case Execution Time, i.e. the maximum time that the interface needs to be executing to serve the call.

In general, real-time analysis consists in proving that, for all executing entities, the sum of WCETs + the interference of other tasks are equal or lower than the deadlines, i.e. every execution will complete before the maximum allowed time.

Hope this helps,

Jorge Garrido Balaguer

Universidad Politecnica de Madrid (UPM)