diff options
Diffstat (limited to 'c-user/scheduling-concepts')
| -rw-r--r-- | c-user/scheduling-concepts/background.rst | 13 | ||||
| -rw-r--r-- | c-user/scheduling-concepts/directives.rst | 891 | ||||
| -rw-r--r-- | c-user/scheduling-concepts/index.rst | 2 | ||||
| -rw-r--r-- | c-user/scheduling-concepts/introduction.rst | 86 | ||||
| -rw-r--r-- | c-user/scheduling-concepts/smp-schedulers.rst | 9 |
5 files changed, 663 insertions, 338 deletions
diff --git a/c-user/scheduling-concepts/background.rst b/c-user/scheduling-concepts/background.rst index 7f8a63d..38b77ee 100644 --- a/c-user/scheduling-concepts/background.rst +++ b/c-user/scheduling-concepts/background.rst @@ -117,10 +117,7 @@ Task Priority and Scheduling The most significant task scheduling modification mechanism is the ability for the user to assign a priority level to each individual task when it is created -and to alter a task's priority at run-time. The maximum priority level depends -on the configured scheduler. A lower priority level means higher priority -(higher importance). The maximum priority level of the default uniprocessor -scheduler is 255. +and to alter a task's priority at run-time, see :ref:`TaskPriority`. .. index:: preemption @@ -163,7 +160,7 @@ Manual Round-Robin The final mechanism for altering the RTEMS scheduling algorithm is called manual round-robin. Manual round-robin is invoked by using -the ``rtems_task_wake_after`` directive with a time interval of +the ``rtems_task_wake_after`` directive with a ``ticks`` parameter of ``RTEMS_YIELD_PROCESSOR``. This allows a task to give up the processor and be immediately returned to the ready chain at the end of its priority group. If no other tasks of the same priority are ready to run, then the task does not @@ -246,7 +243,7 @@ of the following conditions: option and the requested semaphore is unavailable. - The running task issues a ``rtems_task_wake_after`` directive which blocks - the task for the given time interval. If the time interval specified is + the task for the given count of ticks. If the count of ticks specified is zero, the task yields the processor and remains in the ready state. - The running task issues a ``rtems_task_wake_when`` directive which blocks the @@ -283,8 +280,8 @@ conditions: - A running task issues a ``rtems_semaphore_release`` directive which releases the semaphore on which the blocked task is waiting. -- A timeout interval expires for a task which was blocked by a call to the - ``rtems_task_wake_after`` directive. +- The requested count of ticks has elapsed for a task which was blocked by a + call to the ``rtems_task_wake_after`` directive. - A timeout period expires for a task which blocked by a call to the ``rtems_task_wake_when`` directive. diff --git a/c-user/scheduling-concepts/directives.rst b/c-user/scheduling-concepts/directives.rst index 5b1246f..115b4fa 100644 --- a/c-user/scheduling-concepts/directives.rst +++ b/c-user/scheduling-concepts/directives.rst @@ -1,424 +1,707 @@ .. SPDX-License-Identifier: CC-BY-SA-4.0 -.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) +.. Copyright (C) 2013, 2021 embedded brains GmbH & Co. KG +.. Copyright (C) 1988, 2017 On-Line Applications Research Corporation (OAR) + +.. This file is part of the RTEMS quality process and was automatically +.. generated. If you find something that needs to be fixed or +.. worded better please post a report or patch to an RTEMS mailing list +.. or raise a bug report: +.. +.. https://www.rtems.org/bugs.html +.. +.. For information on updating and regenerating please refer to the How-To +.. section in the Software Requirements Engineering chapter of the +.. RTEMS Software Engineering manual. The manual is provided as a part of +.. a release. For development sources please refer to the online +.. documentation at: +.. +.. https://docs.rtems.org + +.. _SchedulerManagerDirectives: Directives ========== -This section details the scheduler manager. A subsection is dedicated to each -of these services and describes the calling sequence, related constants, usage, -and status codes. +This section details the directives of the Scheduler Manager. A subsection is +dedicated to each of this manager's directives and lists the calling sequence, +parameters, description, return values, and notes of the directive. + +.. Generated from spec:/rtems/scheduler/if/ident .. raw:: latex - \clearpage + \clearpage -.. _rtems_scheduler_ident: +.. index:: rtems_scheduler_ident() -SCHEDULER_IDENT - Get ID of a scheduler ---------------------------------------- +.. _InterfaceRtemsSchedulerIdent: + +rtems_scheduler_ident() +----------------------- + +Identifies a scheduler by the object name. + +.. rubric:: CALLING SEQUENCE: + +.. code-block:: c + + rtems_status_code rtems_scheduler_ident( rtems_name name, rtems_id *id ); + +.. rubric:: PARAMETERS: + +``name`` + This parameter is the scheduler name to look up. + +``id`` + This parameter is the pointer to an :ref:`InterfaceRtemsId` object. When + the directive call is successful, the identifier of the scheduler will be + stored in this object. -CALLING SEQUENCE: - .. code-block:: c +.. rubric:: DESCRIPTION: - rtems_status_code rtems_scheduler_ident( - rtems_name name, - rtems_id *id - ); +This directive obtains a scheduler identifier associated with the scheduler +name specified in ``name``. -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table +.. rubric:: RETURN VALUES: - * - ``RTEMS_SUCCESSFUL`` - - Successful operation. - * - ``RTEMS_INVALID_ADDRESS`` - - The ``id`` parameter is ``NULL``. - * - ``RTEMS_INVALID_NAME`` - - Invalid scheduler name. +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. -DESCRIPTION: - Identifies a scheduler by its name. The scheduler name is determined by - the scheduler configuration. See :ref:`ConfigurationSchedulerTable` - and :ref:`CONFIGURE_SCHEDULER_NAME`. +:c:macro:`RTEMS_INVALID_NAME` + There was no scheduler associated with the name. -NOTES: - None. +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``id`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. + +.. rubric:: NOTES: + +The scheduler name is determined by the scheduler configuration. + +The scheduler identifier is used with other scheduler related directives to +access the scheduler. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within any runtime context. + +* The directive will not cause the calling task to be preempted. + +.. Generated from spec:/rtems/scheduler/if/ident-by-processor .. raw:: latex - \clearpage + \clearpage + +.. index:: rtems_scheduler_ident_by_processor() + +.. _InterfaceRtemsSchedulerIdentByProcessor: -.. _rtems_scheduler_ident_by_processor: +rtems_scheduler_ident_by_processor() +------------------------------------ -SCHEDULER_IDENT_BY_PROCESSOR - Get ID of a scheduler by processor ------------------------------------------------------------------ +Identifies a scheduler by the processor index. -CALLING SEQUENCE: - .. code-block:: c +.. rubric:: CALLING SEQUENCE: - rtems_status_code rtems_scheduler_ident_by_processor( - uint32_t cpu_index, - rtems_id *id - ); +.. code-block:: c -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table + rtems_status_code rtems_scheduler_ident_by_processor( + uint32_t cpu_index, + rtems_id *id + ); - * - ``RTEMS_SUCCESSFUL`` - - Successful operation. - * - ``RTEMS_INVALID_ADDRESS`` - - The ``id`` parameter is ``NULL``. - * - ``RTEMS_INVALID_NAME`` - - Invalid processor index. - * - ``RTEMS_INCORRECT_STATE`` - - The processor index is valid, however, this processor is not owned by - a scheduler. +.. rubric:: PARAMETERS: -DESCRIPTION: - Identifies a scheduler by a processor. +``cpu_index`` + This parameter is the processor index to identify the scheduler. -NOTES: - None. +``id`` + This parameter is the pointer to an :ref:`InterfaceRtemsId` object. When + the directive call is successful, the identifier of the scheduler will be + stored in this object. + +.. rubric:: RETURN VALUES: + +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. + +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``id`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. + +:c:macro:`RTEMS_INVALID_NAME` + The processor index was invalid. + +:c:macro:`RTEMS_INCORRECT_STATE` + The processor index was valid, however, the corresponding processor was not + owned by a scheduler. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within any runtime context. + +* The directive will not cause the calling task to be preempted. + +.. Generated from spec:/rtems/scheduler/if/ident-by-processor-set .. raw:: latex - \clearpage + \clearpage + +.. index:: rtems_scheduler_ident_by_processor_set() + +.. _InterfaceRtemsSchedulerIdentByProcessorSet: + +rtems_scheduler_ident_by_processor_set() +---------------------------------------- + +Identifies a scheduler by the processor set. + +.. rubric:: CALLING SEQUENCE: + +.. code-block:: c + + rtems_status_code rtems_scheduler_ident_by_processor_set( + size_t cpusetsize, + const cpu_set_t *cpuset, + rtems_id *id + ); + +.. rubric:: PARAMETERS: + +``cpusetsize`` + This parameter is the size of the processor set referenced by ``cpuset`` in + bytes. The size shall be positive. + +``cpuset`` + This parameter is the pointer to a :c:type:`cpu_set_t`. The referenced + processor set will be used to identify the scheduler. -.. _rtems_scheduler_ident_by_processor_set: +``id`` + This parameter is the pointer to an :ref:`InterfaceRtemsId` object. When + the directive call is successful, the identifier of the scheduler will be + stored in this object. -SCHEDULER_IDENT_BY_PROCESSOR_SET - Get ID of a scheduler by processor set -------------------------------------------------------------------------- +.. rubric:: DESCRIPTION: -CALLING SEQUENCE: - .. code-block:: c +The scheduler is selected according to the highest numbered online processor in +the specified processor set. - rtems_status_code rtems_scheduler_ident_by_processor_set( - size_t cpusetsize, - const cpu_set_t *cpuset, - rtems_id *id - ); +.. rubric:: RETURN VALUES: -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. - * - ``RTEMS_SUCCESSFUL`` - - Successful operation. - * - ``RTEMS_INVALID_ADDRESS`` - - The ``id`` parameter is ``NULL``. - * - ``RTEMS_INVALID_SIZE`` - - Invalid processor set size. - * - ``RTEMS_INVALID_NAME`` - - The processor set contains no online processor. - * - ``RTEMS_INCORRECT_STATE`` - - The processor set is valid, however, the highest numbered online - processor in the specified processor set is not owned by a scheduler. +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``id`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. -DESCRIPTION: - Identifies a scheduler by a processor set. The scheduler is selected - according to the highest numbered online processor in the specified - processor set. +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``cpuset`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. -NOTES: - None. +:c:macro:`RTEMS_INVALID_SIZE` + The processor set size was invalid. + +:c:macro:`RTEMS_INVALID_NAME` + The processor set contained no online processor. + +:c:macro:`RTEMS_INCORRECT_STATE` + The processor set was valid, however, the highest numbered online processor + in the processor set was not owned by a scheduler. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within any runtime context. + +* The directive will not cause the calling task to be preempted. + +.. Generated from spec:/rtems/scheduler/if/get-maximum-priority .. raw:: latex - \clearpage + \clearpage + +.. index:: rtems_scheduler_get_maximum_priority() + +.. _InterfaceRtemsSchedulerGetMaximumPriority: + +rtems_scheduler_get_maximum_priority() +-------------------------------------- -.. _rtems_scheduler_get_maximum_priority: +Gets the maximum task priority of the scheduler. -SCHEDULER_GET_MAXIMUM_PRIORITY - Get maximum task priority of a scheduler -------------------------------------------------------------------------- +.. rubric:: CALLING SEQUENCE: -CALLING SEQUENCE: - .. code-block:: c +.. code-block:: c - rtems_status_code rtems_scheduler_get_maximum_priority( - rtems_id scheduler_id, - rtems_task_priority *priority - ); + rtems_status_code rtems_scheduler_get_maximum_priority( + rtems_id scheduler_id, + rtems_task_priority *priority + ); -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table +.. rubric:: PARAMETERS: - * - ``RTEMS_SUCCESSFUL`` - - Successful operation. - * - ``RTEMS_INVALID_ID`` - - Invalid scheduler instance identifier. - * - ``RTEMS_INVALID_ADDRESS`` - - The ``priority`` parameter is ``NULL``. +``scheduler_id`` + This parameter is the scheduler identifier. -DESCRIPTION: - Returns the maximum task priority of the specified scheduler instance in - ``priority``. +``priority`` + This parameter is the pointer to an :ref:`InterfaceRtemsTaskPriority` + object. When the directive the maximum priority of the scheduler will be + stored in this object. -NOTES: - None. +.. rubric:: RETURN VALUES: + +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. + +:c:macro:`RTEMS_INVALID_ID` + There was no scheduler associated with the identifier specified by + ``scheduler_id``. + +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``priority`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within any runtime context. + +* The directive will not cause the calling task to be preempted. + +.. Generated from spec:/rtems/scheduler/if/map-priority-to-posix .. raw:: latex - \clearpage + \clearpage + +.. index:: rtems_scheduler_map_priority_to_posix() + +.. _InterfaceRtemsSchedulerMapPriorityToPosix: -.. _rtems_scheduler_map_priority_to_posix: +rtems_scheduler_map_priority_to_posix() +--------------------------------------- + +Maps a Classic API task priority to the corresponding POSIX thread priority. + +.. rubric:: CALLING SEQUENCE: + +.. code-block:: c + + rtems_status_code rtems_scheduler_map_priority_to_posix( + rtems_id scheduler_id, + rtems_task_priority priority, + int *posix_priority + ); + +.. rubric:: PARAMETERS: + +``scheduler_id`` + This parameter is the scheduler identifier. + +``priority`` + This parameter is the Classic API task priority to map. + +``posix_priority`` + This parameter is the pointer to an ``int`` object. When the directive + call is successful, the POSIX thread priority value corresponding to the + specified Classic API task priority value will be stored in this object. + +.. rubric:: RETURN VALUES: -SCHEDULER_MAP_PRIORITY_TO_POSIX - Map task priority to POSIX thread prority ---------------------------------------------------------------------------- +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. -CALLING SEQUENCE: - .. code-block:: c +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``posix_priority`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. - rtems_status_code rtems_scheduler_map_priority_to_posix( - rtems_id scheduler_id, - rtems_task_priority priority, - int *posix_priority - ); +:c:macro:`RTEMS_INVALID_ID` + There was no scheduler associated with the identifier specified by + ``scheduler_id``. -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table +:c:macro:`RTEMS_INVALID_PRIORITY` + The Classic API task priority was invalid. - * - ``RTEMS_SUCCESSFUL`` - - Successful operation. - * - ``RTEMS_INVALID_ADDRESS`` - - The ``posix_priority`` parameter is ``NULL``. - * - ``RTEMS_INVALID_ID`` - - Invalid scheduler instance identifier. - * - ``RTEMS_INVALID_PRIORITY`` - - Invalid task priority. +.. rubric:: CONSTRAINTS: -DESCRIPTION: - Maps a task priority to the corresponding POSIX thread priority. +The following constraints apply to this directive: -NOTES: - None. +* The directive may be called from within any runtime context. + +* The directive will not cause the calling task to be preempted. + +.. Generated from spec:/rtems/scheduler/if/map-priority-from-posix .. raw:: latex - \clearpage + \clearpage + +.. index:: rtems_scheduler_map_priority_from_posix() + +.. _InterfaceRtemsSchedulerMapPriorityFromPosix: + +rtems_scheduler_map_priority_from_posix() +----------------------------------------- + +Maps a POSIX thread priority to the corresponding Classic API task priority. + +.. rubric:: CALLING SEQUENCE: + +.. code-block:: c + + rtems_status_code rtems_scheduler_map_priority_from_posix( + rtems_id scheduler_id, + int posix_priority, + rtems_task_priority *priority + ); + +.. rubric:: PARAMETERS: -.. _rtems_scheduler_map_priority_from_posix: +``scheduler_id`` + This parameter is the scheduler identifier. -SCHEDULER_MAP_PRIORITY_FROM_POSIX - Map POSIX thread prority to task priority ------------------------------------------------------------------------------ +``posix_priority`` + This parameter is the POSIX thread priority to map. -CALLING SEQUENCE: - .. code-block:: c +``priority`` + This parameter is the pointer to an :ref:`InterfaceRtemsTaskPriority` + object. When the directive call is successful, the Classic API task + priority value corresponding to the specified POSIX thread priority value + will be stored in this object. - rtems_status_code rtems_scheduler_map_priority_from_posix( - rtems_id scheduler_id, - int posix_priority, - rtems_task_priority *priority - ); +.. rubric:: RETURN VALUES: -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. - * - ``RTEMS_SUCCESSFUL`` - - Successful operation. - * - ``RTEMS_INVALID_ADDRESS`` - - The ``priority`` parameter is ``NULL``. - * - ``RTEMS_INVALID_ID`` - - Invalid scheduler instance identifier. - * - ``RTEMS_INVALID_PRIORITY`` - - Invalid POSIX thread priority. +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``priority`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. -DESCRIPTION: - Maps a POSIX thread priority to the corresponding task priority. +:c:macro:`RTEMS_INVALID_ID` + There was no scheduler associated with the identifier specified by + ``scheduler_id``. -NOTES: - None. +:c:macro:`RTEMS_INVALID_PRIORITY` + The POSIX thread priority was invalid. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within any runtime context. + +* The directive will not cause the calling task to be preempted. + +.. Generated from spec:/rtems/scheduler/if/get-processor .. raw:: latex - \clearpage + \clearpage + +.. index:: rtems_scheduler_get_processor() + +.. _InterfaceRtemsSchedulerGetProcessor: + +rtems_scheduler_get_processor() +------------------------------- + +Returns the index of the current processor. + +.. rubric:: CALLING SEQUENCE: -.. _rtems_scheduler_get_processor: +.. code-block:: c -SCHEDULER_GET_PROCESSOR - Get current processor index ------------------------------------------------------ + uint32_t rtems_scheduler_get_processor( void ); -CALLING SEQUENCE: - .. code-block:: c +.. rubric:: DESCRIPTION: - uint32_t rtems_scheduler_get_processor( void ); +Where the system was built with SMP support disabled, this directive evaluates +to a compile time constant of zero. -DIRECTIVE STATUS CODES: - This directive returns the index of the current processor. +Where the system was built with SMP support enabled, this directive returns the +index of the current processor. The set of processor indices is the range of +integers starting with zero up to +:ref:`InterfaceRtemsSchedulerGetProcessorMaximum` minus one. -DESCRIPTION: - In uniprocessor configurations, a value of zero will be returned. +.. rubric:: RETURN VALUES: - In SMP configurations, an architecture specific method is used to obtain the - index of the current processor in the system. The set of processor indices - is the range of integers starting with zero up to the processor count minus - one. +Returns the index of the current processor. - Outside of sections with disabled thread dispatching the current processor - index may change after every instruction since the thread may migrate from - one processor to another. Sections with disabled interrupts are sections - with thread dispatching disabled. +.. rubric:: NOTES: -NOTES: - None. +Outside of sections with disabled thread dispatching the current processor +index may change after every instruction since the thread may migrate from one +processor to another. Sections with disabled interrupts are sections with +thread dispatching disabled. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within any runtime context. + +* The directive will not cause the calling task to be preempted. + +.. Generated from spec:/rtems/scheduler/if/get-processor-maximum .. raw:: latex - \clearpage + \clearpage + +.. index:: rtems_scheduler_get_processor_maximum() + +.. _InterfaceRtemsSchedulerGetProcessorMaximum: + +rtems_scheduler_get_processor_maximum() +--------------------------------------- + +Returns the processor maximum supported by the system. -.. _rtems_scheduler_get_processor_maximum: +.. rubric:: CALLING SEQUENCE: -SCHEDULER_GET_PROCESSOR_MAXIMUM - Get processor maximum -------------------------------------------------------- +.. code-block:: c -CALLING SEQUENCE: - .. code-block:: c + uint32_t rtems_scheduler_get_processor_maximum( void ); - uint32_t rtems_scheduler_get_processor_maximum( void ); +.. rubric:: DESCRIPTION: -DIRECTIVE STATUS CODES: - This directive returns the processor maximum supported by the system. +Where the system was built with SMP support disabled, this directive evaluates +to a compile time constant of one. -DESCRIPTION: - In uniprocessor configurations, a value of one will be returned. +Where the system was built with SMP support enabled, this directive returns the +minimum of the processors (physically or virtually) available at the +:term:`target` and the configured processor maximum (see +:ref:`CONFIGURE_MAXIMUM_PROCESSORS`). Not all processors in the range from +processor index zero to the last processor index (which is the processor +maximum minus one) may be configured to be used by a scheduler or may be online +(online processors have a scheduler assigned). - In SMP configurations, this directive returns the minimum of the processors - (physically or virtually) available by the platform and the configured - processor maximum. Not all processors in the range from processor index - zero to the last processor index (which is the processor maximum minus one) - may be configured to be used by a scheduler or online (online processors - have a scheduler assigned). +.. rubric:: RETURN VALUES: -NOTES: - None. +Returns the processor maximum supported by the system. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within any runtime context. + +* The directive will not cause the calling task to be preempted. + +.. Generated from spec:/rtems/scheduler/if/get-processor-set .. raw:: latex - \clearpage + \clearpage + +.. index:: rtems_scheduler_get_processor_set() + +.. _InterfaceRtemsSchedulerGetProcessorSet: + +rtems_scheduler_get_processor_set() +----------------------------------- + +Gets the set of processors owned by the scheduler. + +.. rubric:: CALLING SEQUENCE: -.. _rtems_scheduler_get_processor_set: +.. code-block:: c -SCHEDULER_GET_PROCESSOR_SET - Get processor set of a scheduler --------------------------------------------------------------- + rtems_status_code rtems_scheduler_get_processor_set( + rtems_id scheduler_id, + size_t cpusetsize, + cpu_set_t *cpuset + ); -CALLING SEQUENCE: - .. code-block:: c +.. rubric:: PARAMETERS: - rtems_status_code rtems_scheduler_get_processor_set( - rtems_id scheduler_id, - size_t cpusetsize, - cpu_set_t *cpuset - ); +``scheduler_id`` + This parameter is the scheduler identifier. -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table +``cpusetsize`` + This parameter is the size of the processor set referenced by ``cpuset`` in + bytes. - * - ``RTEMS_SUCCESSFUL`` - - Successful operation. - * - ``RTEMS_INVALID_ID`` - - Invalid scheduler instance identifier. - * - ``RTEMS_INVALID_ADDRESS`` - - The ``cpuset`` parameter is ``NULL``. - * - ``RTEMS_INVALID_NUMBER`` - - The processor set buffer is too small for the set of processors owned - by the scheduler instance. +``cpuset`` + This parameter is the pointer to a :c:type:`cpu_set_t` object. When the + directive call is successful, the processor set of the scheduler will be + stored in this object. A set bit in the processor set means that the + corresponding processor is owned by the scheduler, otherwise the bit is + cleared. -DESCRIPTION: - Returns the processor set owned by the scheduler instance in ``cpuset``. A - set bit in the processor set means that this processor is owned by the - scheduler instance and a cleared bit means the opposite. +.. rubric:: RETURN VALUES: -NOTES: - None. +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. + +:c:macro:`RTEMS_INVALID_ADDRESS` + The ``cpuset`` parameter was `NULL + <https://en.cppreference.com/w/c/types/NULL>`_. + +:c:macro:`RTEMS_INVALID_ID` + There was no scheduler associated with the identifier specified by + ``scheduler_id``. + +:c:macro:`RTEMS_INVALID_SIZE` + The provided processor set was too small for the set of processors owned by + the scheduler. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within any runtime context. + +* The directive will not cause the calling task to be preempted. + +.. Generated from spec:/rtems/scheduler/if/add-processor .. raw:: latex - \clearpage + \clearpage + +.. index:: rtems_scheduler_add_processor() + +.. _InterfaceRtemsSchedulerAddProcessor: -.. _rtems_scheduler_add_processor: +rtems_scheduler_add_processor() +------------------------------- -SCHEDULER_ADD_PROCESSOR - Add processor to a scheduler ------------------------------------------------------- +Adds the processor to the set of processors owned by the scheduler. -CALLING SEQUENCE: - .. code-block:: c +.. rubric:: CALLING SEQUENCE: - rtems_status_code rtems_scheduler_add_processor( - rtems_id scheduler_id, - uint32_t cpu_index - ); +.. code-block:: c -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table + rtems_status_code rtems_scheduler_add_processor( + rtems_id scheduler_id, + uint32_t cpu_index + ); - * - ``RTEMS_SUCCESSFUL`` - - Successful operation. - * - ``RTEMS_INVALID_ID`` - - Invalid scheduler instance identifier. - * - ``RTEMS_NOT_CONFIGURED`` - - The processor is not configured to be used by the application. - * - ``RTEMS_INCORRECT_STATE`` - - The processor is configured to be used by the application, however, it - is not online. - * - ``RTEMS_RESOURCE_IN_USE`` - - The processor is already assigned to a scheduler instance. +.. rubric:: PARAMETERS: -DESCRIPTION: - Adds a processor to the set of processors owned by the specified scheduler - instance. +``scheduler_id`` + This parameter is the scheduler identifier. -NOTES: - Must be called from task context. This operation obtains and releases the - objects allocator lock. +``cpu_index`` + This parameter is the index of the processor to add. + +.. rubric:: DESCRIPTION: + +This directive adds the processor specified by the ``cpu_index`` to the +scheduler specified by ``scheduler_id``. + +.. rubric:: RETURN VALUES: + +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. + +:c:macro:`RTEMS_INVALID_ID` + There was no scheduler associated with the identifier specified by + ``scheduler_id``. + +:c:macro:`RTEMS_NOT_CONFIGURED` + The processor was not configured to be used by the application. + +:c:macro:`RTEMS_INCORRECT_STATE` + The processor was configured to be used by the application, however, it was + not online. + +:c:macro:`RTEMS_RESOURCE_IN_USE` + The processor was already assigned to a scheduler. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within device driver initialization context. + +* The directive may be called from within task context. + +* The directive may obtain and release the object allocator mutex. This may + cause the calling task to be preempted. + +.. Generated from spec:/rtems/scheduler/if/remove-processor .. raw:: latex - \clearpage - -.. _rtems_scheduler_remove_processor: - -SCHEDULER_REMOVE_PROCESSOR - Remove processor from a scheduler --------------------------------------------------------------- - -CALLING SEQUENCE: - .. code-block:: c - - rtems_status_code rtems_scheduler_remove_processor( - rtems_id scheduler_id, - uint32_t cpu_index - ); - -DIRECTIVE STATUS CODES: - .. list-table:: - :class: rtems-table - - * - ``RTEMS_SUCCESSFUL`` - - Successful operation. - * - ``RTEMS_INVALID_ID`` - - Invalid scheduler instance identifier. - * - ``RTEMS_INVALID_NUMBER`` - - The processor is not owned by the specified scheduler instance. - * - ``RTEMS_RESOURCE_IN_USE`` - - The set of processors owned by the specified scheduler instance would - be empty after the processor removal and there exists a non-idle task - that uses this scheduler instance as its home scheduler instance. - * - ``RTEMS_RESOURCE_IN_USE`` - - A task with a restricted processor affinity exists that uses this - scheduler instance as its home scheduler instance and it would be no - longer possible to allocate a processor for this task after the - removal of this processor. - -DESCRIPTION: - Removes a processor from set of processors owned by the specified scheduler - instance. - -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. + \clearpage + +.. index:: rtems_scheduler_remove_processor() + +.. _InterfaceRtemsSchedulerRemoveProcessor: + +rtems_scheduler_remove_processor() +---------------------------------- + +Removes the processor from the set of processors owned by the scheduler. + +.. rubric:: CALLING SEQUENCE: + +.. code-block:: c + + rtems_status_code rtems_scheduler_remove_processor( + rtems_id scheduler_id, + uint32_t cpu_index + ); + +.. rubric:: PARAMETERS: + +``scheduler_id`` + This parameter is the scheduler identifier. + +``cpu_index`` + This parameter is the index of the processor to remove. + +.. rubric:: DESCRIPTION: + +This directive removes the processor specified by the ``cpu_index`` from the +scheduler specified by ``scheduler_id``. + +.. rubric:: RETURN VALUES: + +:c:macro:`RTEMS_SUCCESSFUL` + The requested operation was successful. + +:c:macro:`RTEMS_INVALID_ID` + There was no scheduler associated with the identifier specified by + ``scheduler_id``. + +:c:macro:`RTEMS_INVALID_NUMBER` + The processor was not owned by the scheduler. + +:c:macro:`RTEMS_RESOURCE_IN_USE` + The processor was required by at least one non-idle task that used the + scheduler as its :term:`home scheduler`. + +:c:macro:`RTEMS_RESOURCE_IN_USE` + The processor was the last processor owned by the scheduler and there was + at least one task that used the scheduler as a :term:`helping scheduler`. + +.. rubric:: NOTES: + +Removing a processor from a scheduler is a complex operation that involves all +tasks of the system. + +.. rubric:: CONSTRAINTS: + +The following constraints apply to this directive: + +* The directive may be called from within device driver initialization context. + +* The directive may be called from within task context. + +* The directive may obtain and release the object allocator mutex. This may + cause the calling task to be preempted. diff --git a/c-user/scheduling-concepts/index.rst b/c-user/scheduling-concepts/index.rst index 6b16f1b..ee9aa26 100644 --- a/c-user/scheduling-concepts/index.rst +++ b/c-user/scheduling-concepts/index.rst @@ -1,6 +1,6 @@ .. SPDX-License-Identifier: CC-BY-SA-4.0 -.. Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de) +.. Copyright (C) 2020 embedded brains GmbH & Co. KG .. index:: scheduling .. index:: task scheduling diff --git a/c-user/scheduling-concepts/introduction.rst b/c-user/scheduling-concepts/introduction.rst index 92da6de..527d103 100644 --- a/c-user/scheduling-concepts/introduction.rst +++ b/c-user/scheduling-concepts/introduction.rst @@ -1,42 +1,86 @@ .. SPDX-License-Identifier: CC-BY-SA-4.0 -.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) +.. Copyright (C) 2013, 2021 embedded brains GmbH & Co. KG +.. Copyright (C) 1988, 2017 On-Line Applications Research Corporation (OAR) + +.. This file is part of the RTEMS quality process and was automatically +.. generated. If you find something that needs to be fixed or +.. worded better please post a report or patch to an RTEMS mailing list +.. or raise a bug report: +.. +.. https://www.rtems.org/bugs.html +.. +.. For information on updating and regenerating please refer to the How-To +.. section in the Software Requirements Engineering chapter of the +.. RTEMS Software Engineering manual. The manual is provided as a part of +.. a release. For development sources please refer to the online +.. documentation at: +.. +.. https://docs.rtems.org + +.. Generated from spec:/rtems/scheduler/if/group + +.. _SchedulerManagerIntroduction: Introduction ============ +.. The following list was generated from: +.. spec:/rtems/scheduler/if/ident +.. spec:/rtems/scheduler/if/ident-by-processor +.. spec:/rtems/scheduler/if/ident-by-processor-set +.. spec:/rtems/scheduler/if/get-maximum-priority +.. spec:/rtems/scheduler/if/map-priority-to-posix +.. spec:/rtems/scheduler/if/map-priority-from-posix +.. spec:/rtems/scheduler/if/get-processor +.. spec:/rtems/scheduler/if/get-processor-maximum +.. spec:/rtems/scheduler/if/get-processor-set +.. spec:/rtems/scheduler/if/add-processor +.. spec:/rtems/scheduler/if/remove-processor + +The scheduling concepts relate to the allocation of processing time for tasks. + The concept of scheduling in real-time systems dictates the ability to provide -an immediate response to specific external events, particularly the necessity of -scheduling tasks to run within a specified time limit after the occurrence of -an event. For example, software embedded in life-support systems used to -monitor hospital patients must take instant action if a change in the patient's +an immediate response to specific external events, particularly the necessity +of scheduling tasks to run within a specified time limit after the occurrence +of an event. For example, software embedded in life-support systems used to +monitor hospital patients must take instant action if a change in the patient’s status is detected. The component of RTEMS responsible for providing this capability is -appropriately called the scheduler. The scheduler's sole purpose is to -allocate the all important resource of processor time to the various tasks -competing for attention. - -The directives provided by the scheduler manager are: +appropriately called the scheduler. The scheduler’s sole purpose is to allocate +the all important resource of processor time to the various tasks competing for +attention. The directives provided by the Scheduler Manager are: -- :ref:`rtems_scheduler_ident` +* :ref:`InterfaceRtemsSchedulerIdent` - Identifies a scheduler by the object + name. -- :ref:`rtems_scheduler_ident_by_processor` +* :ref:`InterfaceRtemsSchedulerIdentByProcessor` - Identifies a scheduler by + the processor index. -- :ref:`rtems_scheduler_ident_by_processor_set` +* :ref:`InterfaceRtemsSchedulerIdentByProcessorSet` - Identifies a scheduler by + the processor set. -- :ref:`rtems_scheduler_get_maximum_priority` +* :ref:`InterfaceRtemsSchedulerGetMaximumPriority` - Gets the maximum task + priority of the scheduler. -- :ref:`rtems_scheduler_map_priority_to_posix` +* :ref:`InterfaceRtemsSchedulerMapPriorityToPosix` - Maps a Classic API task + priority to the corresponding POSIX thread priority. -- :ref:`rtems_scheduler_map_priority_from_posix` +* :ref:`InterfaceRtemsSchedulerMapPriorityFromPosix` - Maps a POSIX thread + priority to the corresponding Classic API task priority. -- :ref:`rtems_scheduler_get_processor` +* :ref:`InterfaceRtemsSchedulerGetProcessor` - Returns the index of the current + processor. -- :ref:`rtems_scheduler_get_processor_maximum` +* :ref:`InterfaceRtemsSchedulerGetProcessorMaximum` - Returns the processor + maximum supported by the system. -- :ref:`rtems_scheduler_get_processor_set` +* :ref:`InterfaceRtemsSchedulerGetProcessorSet` - Gets the set of processors + owned by the scheduler. -- :ref:`rtems_scheduler_add_processor` +* :ref:`InterfaceRtemsSchedulerAddProcessor` - Adds the processor to the set of + processors owned by the scheduler. -- :ref:`rtems_scheduler_remove_processor` +* :ref:`InterfaceRtemsSchedulerRemoveProcessor` - Removes the processor from + the set of processors owned by the scheduler. diff --git a/c-user/scheduling-concepts/smp-schedulers.rst b/c-user/scheduling-concepts/smp-schedulers.rst index cfab04f..d6c1dc6 100644 --- a/c-user/scheduling-concepts/smp-schedulers.rst +++ b/c-user/scheduling-concepts/smp-schedulers.rst @@ -45,7 +45,7 @@ Deterministic Priority SMP Scheduler A fixed-priority scheduler which uses a table of chains with one chain per priority level for the ready tasks. The maximum priority level is configurable. By default, the maximum priority level is 255 (256 priority -levels). +levels), see :ref:`CONFIGURE_MAXIMUM_PRIORITY`. .. _SchedulerSMPPrioritySimple: @@ -64,6 +64,7 @@ Arbitrary Processor Affinity Priority SMP Scheduler A fixed-priority scheduler which uses a table of chains with one chain per priority level for the ready tasks. The maximum priority level is configurable. By default, the maximum priority level is 255 (256 priority -levels). This scheduler supports arbitrary task processor affinities. The -worst-case run-time complexity of some scheduler operations exceeds -:math:`O(n)` while :math:`n` is the count of ready tasks. +levels), see :ref:`CONFIGURE_MAXIMUM_PRIORITY`. This scheduler supports +arbitrary task processor affinities. The worst-case run-time complexity of +some scheduler operations exceeds :math:`O(n)` while :math:`n` is the count of +ready tasks. |