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

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.

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)

2018-01-25 16:01 GMT+01:00 Javier Hidalgo Carrió <javier.hidalgo_carrio@xxxxxxx>:

Dear Tasters,
I would like to know whether the PI queue when size > 1, Is it a circular buffer?

In addition: what is the influence of the attributes in the behavior. I read in the taste documentation that:

* Inter-arrival time, is the minimum expected execution time in ms
* Deadline, is the maximum expected execution time in ms
* WCET. I don't find information about this.

How this affect the execution? In case the buffer for the queue is full. Is there a manner to know when new data arrive to the PI and is dropped because of queue full?

Regards,
-- 
Javier Hidalgo-Carrió
Researcher
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