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Diffstat (limited to 'c-user/symmetric_multiprocessing_services.rst')
| -rw-r--r-- | c-user/symmetric_multiprocessing_services.rst | 237 |
1 files changed, 0 insertions, 237 deletions
diff --git a/c-user/symmetric_multiprocessing_services.rst b/c-user/symmetric_multiprocessing_services.rst index 5637063..4f1e5bb 100644 --- a/c-user/symmetric_multiprocessing_services.rst +++ b/c-user/symmetric_multiprocessing_services.rst @@ -48,14 +48,6 @@ The application level services currently provided are: - rtems_scheduler_remove_processor_ - Remove processor from a scheduler -- rtems_task_get_scheduler_ - Get scheduler of a task - -- rtems_task_set_scheduler_ - Set scheduler of a task - -- rtems_task_get_affinity_ - Get task processor affinity - -- rtems_task_set_affinity_ - Set task processor affinity - Background ========== @@ -583,37 +575,6 @@ the heir thread must be used during interrupt processing. For this purpose a temporary per-processor stack is set up which may be used by the interrupt prologue before the stack is switched to the interrupt stack. -Operations -========== - -Setting Affinity to a Single Processor --------------------------------------- - -On some embedded applications targeting SMP systems, it may be beneficial to -lock individual tasks to specific processors. In this way, one can designate a -processor for I/O tasks, another for computation, etc.. The following -illustrates the code sequence necessary to assign a task an affinity for -processor with index ``processor_index``. - -.. code-block:: c - - #include <rtems.h> - #include <assert.h> - - void pin_to_processor(rtems_id task_id, int processor_index) - { - rtems_status_code sc; - cpu_set_t cpuset; - CPU_ZERO(&cpuset); - CPU_SET(processor_index, &cpuset); - sc = rtems_task_set_affinity(task_id, sizeof(cpuset), &cpuset); - assert(sc == RTEMS_SUCCESSFUL); - } - -It is important to note that the ``cpuset`` is not validated until the -``rtems_task_set_affinity`` call is made. At that point, it is validated -against the current system configuration. - Directives ========== @@ -840,201 +801,3 @@ NOTES: Must be called from task context. This operation obtains and releases the objects allocator lock. Removing a processor from a scheduler is a complex operation that involves all tasks of the system. - -.. raw:: latex - - \clearpage - -.. _rtems_task_get_scheduler: - -TASK_GET_SCHEDULER - Get scheduler of a task --------------------------------------------- - -CALLING SEQUENCE: - .. code-block:: c - - rtems_status_code rtems_task_get_scheduler( - rtems_id task_id, - rtems_id *scheduler_id - ); - -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table - - * - ``RTEMS_SUCCESSFUL`` - - successful operation - * - ``RTEMS_INVALID_ADDRESS`` - - ``scheduler_id`` is NULL - * - ``RTEMS_INVALID_ID`` - - invalid task id - -DESCRIPTION: - Returns the scheduler identifier of a task identified by ``task_id`` in - ``scheduler_id``. - -NOTES: - None. - -.. raw:: latex - - \clearpage - -.. _rtems_task_set_scheduler: -.. _TASK_SET_SCHEDULER - Set scheduler of a task: - -TASK_SET_SCHEDULER - Set scheduler of a task --------------------------------------------- - -CALLING SEQUENCE: - .. code-block:: c - - rtems_status_code rtems_task_set_scheduler( - rtems_id task_id, - rtems_id scheduler_id - ); - -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table - - * - ``RTEMS_SUCCESSFUL`` - - successful operation - * - ``RTEMS_INVALID_ID`` - - invalid task or scheduler id - * - ``RTEMS_INCORRECT_STATE`` - - the task is in the wrong state to perform a scheduler change - -DESCRIPTION: - Sets the scheduler of a task identified by ``task_id`` to the scheduler - identified by ``scheduler_id``. The scheduler of a task is initialized to - the scheduler of the task that created it. - -NOTES: - None. - -EXAMPLE: - .. code-block:: c - :linenos: - - #include <rtems.h> - #include <assert.h> - - void task(rtems_task_argument arg); - - void example(void) - { - rtems_status_code sc; - rtems_id task_id; - rtems_id scheduler_id; - rtems_name scheduler_name; - - scheduler_name = rtems_build_name('W', 'O', 'R', 'K'); - - sc = rtems_scheduler_ident(scheduler_name, &scheduler_id); - assert(sc == RTEMS_SUCCESSFUL); - - sc = rtems_task_create( - rtems_build_name('T', 'A', 'S', 'K'), - 1, - RTEMS_MINIMUM_STACK_SIZE, - RTEMS_DEFAULT_MODES, - RTEMS_DEFAULT_ATTRIBUTES, - &task_id - ); - assert(sc == RTEMS_SUCCESSFUL); - - sc = rtems_task_set_scheduler(task_id, scheduler_id); - assert(sc == RTEMS_SUCCESSFUL); - - sc = rtems_task_start(task_id, task, 0); - assert(sc == RTEMS_SUCCESSFUL); - } - -.. raw:: latex - - \clearpage - -.. _rtems_task_get_affinity: - -TASK_GET_AFFINITY - Get task processor affinity ------------------------------------------------ - -CALLING SEQUENCE: - .. code-block:: c - - rtems_status_code rtems_task_get_affinity( - rtems_id id, - size_t cpusetsize, - cpu_set_t *cpuset - ); - -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table - - * - ``RTEMS_SUCCESSFUL`` - - successful operation - * - ``RTEMS_INVALID_ADDRESS`` - - ``cpuset`` is NULL - * - ``RTEMS_INVALID_ID`` - - invalid task id - * - ``RTEMS_INVALID_NUMBER`` - - the affinity set buffer is too small for the current processor affinity - set of the task - -DESCRIPTION: - Returns the current processor affinity set of the task in ``cpuset``. A - set bit in the affinity set means that the task can execute on this - processor and a cleared bit means the opposite. - -NOTES: - None. - -.. raw:: latex - - \clearpage - -.. _rtems_task_set_affinity: - -TASK_SET_AFFINITY - Set task processor affinity ------------------------------------------------ - -CALLING SEQUENCE: - .. code-block:: c - - rtems_status_code rtems_task_set_affinity( - rtems_id id, - size_t cpusetsize, - const cpu_set_t *cpuset - ); - -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table - - * - ``RTEMS_SUCCESSFUL`` - - successful operation - * - ``RTEMS_INVALID_ADDRESS`` - - ``cpuset`` is NULL - * - ``RTEMS_INVALID_ID`` - - invalid task id - * - ``RTEMS_INVALID_NUMBER`` - - invalid processor affinity set - -DESCRIPTION: - Sets the processor affinity set for the task specified by ``cpuset``. A - set bit in the affinity set means that the task can execute on this - processor and a cleared bit means the opposite. - -NOTES: - This function will not change the scheduler of the task. The intersection - of the processor affinity set and the set of processors owned by the - scheduler of the task must be non-empty. It is not an error if the - processor affinity set contains processors that are not part of the set of - processors owned by the scheduler instance of the task. A task will simply - not run under normal circumstances on these processors since the scheduler - ignores them. Some locking protocols may temporarily use processors that - are not included in the processor affinity set of the task. It is also not - an error if the processor affinity set contains processors that are not - part of the system. |