Thread 2: Need help in understanding exisiting RTEMS code

Sebastian Huber sebastian.huber at embedded-brains.de
Fri Jul 17 13:01:32 UTC 2020


On 17/07/2020 14:22, Richi Dubey wrote:

> I found the line in the documentation: "Since the processor assignment
> is independent of the thread priority the processor indices may move
> from one state to the other."
>
> This is true because the processor assignment is done by the scheduler
> and it gets to choose whether to allocate the highest priority thread
> or not. Right? So if it wants to allocate processor to the lowest
> priority (max. priority number) thread, it can do so?
Yes, the scheduler can use whatever criteria it wants to allocate a 
processor to the threads is manages.
>
> How is the priority of a node different from the priority of its
> thread? How do these two priorities relate to each other?
A thread has not only one priority. It has at least one priority per 
scheduler instance. With the locking protocols it may also inherit 
priorities of other threads. A thread has a list of trees of trees of 
priorities.


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