On 15/07/2020 14:55, Richi Dubey wrote:
On Wed, Jul 15, 2020 at 5:57 PM Richi Dubey <richidu...@gmail.com
<mailto:richidu...@gmail.com>> wrote:
Hi,
I had a small question. The scheduler struct inside percpu.h looks
like:
------------------------------------------------------------------------------------------------------
struct {
/**
* @brief The scheduler control of the scheduler owning this
processor.
*
* This pointer is NULL in case this processor is currently
not used by a
* scheduler instance.
*/
const struct _Scheduler_Control *control;
/**
* @brief The scheduler context of the scheduler owning this
processor.
*
* This pointer is NULL in case this processor is currently
not used by a
* scheduler instance.
*/
const struct Scheduler_Context *context;
/**
* @brief The idle thread for this processor in case it is
online and
* currently not used by a scheduler instance.
*/
struct _Thread_Control *idle_if_online_and_unused;
} Scheduler;
------------------------------------------------------------------------------------------------------
So, does this mean a CPU when active is always either executing an
idle thread and is not being used by a scheduler (so has a thread
attribute in the idle_if_online_and_unused), or is used by a
scheduler and is executing a task ( which can not be an idle
task)? Another equivalent question is do we have an idle scheduler
node, like we have idle predefined threads that run on a CPU?
During system startup the application configuration defines which
processor is available to RTEMS. Every configured and present processor
gets an idle thread assigned which is managed by a scheduler. This is
the starting point of the system. If someone calls
rtems_scheduler_remove_processor(), then a processor gets removed from a
scheduler instance. This processor still has to execute code. For this a
idle thread is used. This idle thread is not managed by a scheduler. If
someone uses rtems_scheduler_add_processor() this idle thread is again
controlled by a scheduler.
_______________________________________________
devel mailing list
devel@rtems.org
http://lists.rtems.org/mailman/listinfo/devel
