Doubt regarding thread creation in RTEMS

[Richi Dubey]

Thank you for the clarification.

I am still having a hard time understanding this. What do you mean by no
code which blocks? Does the thread which executes our task (Say a
function Loop with 30k loops) block? What does block mean here?

On Wed, Jul 22, 2020 at 7:46 PM Sebastian Huber <
sebastian.huber at embedded-brains.de> wrote:

> On 22/07/2020 15:36, Richi Dubey wrote:
>
> >
> > Threads that get created automatically when a CPU starts have their
> > scheduler nodes with node->idle set to the thread itself, while the
> > nodes that are created due to a task being created have NULL in their
> > node->idle (If not using helper function atm).  Am I right?
> >
> > If yes, Why isn't the function _Scheduler_Set_idle_thread() called
> > by _Thread_Create_idle_for_CPU?
> >
> > Trace:
> >
> > exinit.c -> _Thread_Create_idle -> _Thread_Create_idle_for_CPU
> > -> _Scheduler_Start_idle -> _Scheduler_EDF_SMP_Start_idle
> > -> _Scheduler_SMP_Do_start_idle ->_Scheduler_SMP_Release_idle_thread .
> >
> > I am asking this since _Scheduler_Set_idle_thread() is the only
> > function that sets the node->idle value.
>
> I think the description of this member is clear:
>
> /**
>   * @brief Scheduler node for per-thread data.
>   */
> struct Scheduler_Node {
> ...
>
>    /**
>     * @brief The idle thread claimed by this node in case the sticky
> level is
>     * greater than zero and the thread is block or is scheduled on another
>     * scheduler instance.
>     *
>     * This is necessary to ensure the priority ceiling protocols work
> across
>     * scheduler boundaries.
>     */
>
>    struct _Thread_Control *idle;
>
> As I said before, the idle threads are normal threads. The only special
> thing is that they execute no code which blocks. You really have to
> distinguish between threads and scheduler nodes.
>
>
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