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Try to bring all descriptions up to date. Add cross-references to several options. Close #3900.
383 lines
12 KiB
ReStructuredText
383 lines
12 KiB
ReStructuredText
.. SPDX-License-Identifier: CC-BY-SA-4.0
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.. Copyright (C) 2010 Gedare Bloom
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.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
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General Scheduler Configuration
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===============================
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This section describes configuration options related to selecting a
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scheduling algorithm for an application. A scheduler configuration is optional
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and only necessary in very specific circumstances. A normal application
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configuration does not need any of the configuration options described in this
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section.
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By default, the :ref:`Deterministic Priority Scheduler <SchedulerPriority>`
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algorithm is used in uniprocessor configurations. In case SMP is enabled and
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the configured maximum processors
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(:ref:`CONFIGURE_MAXIMUM_PROCESSORS <CONFIGURE_MAXIMUM_PROCESSORS>`) is greater
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than one, then the :ref:`Earliest Deadline First (EDF) SMP Scheduler
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<SchedulerSMPEDF>` is selected as the default scheduler algorithm.
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For the :ref:`schedulers built into
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RTEMS <SchedulingConcepts>`, the configuration is straightforward. All that is
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required is to define the configuration option which specifies which scheduler
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you want for in your application.
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The pluggable scheduler interface also enables the user to provide their own
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scheduling algorithm. If you choose to do this, you must define multiple
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configuration option.
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.. index:: CONFIGURE_SCHEDULER_CBS
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.. _CONFIGURE_SCHEDULER_CBS:
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CONFIGURE_SCHEDULER_CBS
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-----------------------
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CONSTANT:
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``CONFIGURE_SCHEDULER_CBS``
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OPTION TYPE:
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This configuration option is a boolean feature define.
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DEFAULT CONFIGURATION:
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If this configuration option is undefined, then the described feature is not
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enabled.
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DESCRIPTION:
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In case this configuration option is defined, then
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:ref:`Constant Bandwidth Server (CBS) Scheduler <SchedulerCBS>`
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algorithm is made available to the application.
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NOTES:
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This scheduler configuration option is an advanced configuration option.
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Think twice before you use it.
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In case no explicit :ref:`clustered scheduler configuration
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<ConfigurationSchedulersClustered>` is present, then it is used as the
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scheduler for exactly one processor.
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.. index:: CONFIGURE_SCHEDULER_EDF
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.. _CONFIGURE_SCHEDULER_EDF:
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CONFIGURE_SCHEDULER_EDF
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-----------------------
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CONSTANT:
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``CONFIGURE_SCHEDULER_EDF``
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OPTION TYPE:
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This configuration option is a boolean feature define.
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DEFAULT CONFIGURATION:
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If this configuration option is undefined, then the described feature is not
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enabled.
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DESCRIPTION:
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In case this configuration option is defined, then
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:ref:`Earliest Deadline First (EDF) Scheduler <SchedulerEDF>`
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algorithm is made available to the application.
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NOTES:
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This scheduler configuration option is an advanced configuration option.
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Think twice before you use it.
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In case no explicit :ref:`clustered scheduler configuration
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<ConfigurationSchedulersClustered>` is present, then it is used as the
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scheduler for exactly one processor.
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.. index:: CONFIGURE_SCHEDULER_EDF_SMP
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.. _CONFIGURE_SCHEDULER_EDF_SMP:
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CONFIGURE_SCHEDULER_EDF_SMP
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---------------------------
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CONSTANT:
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``CONFIGURE_SCHEDULER_EDF_SMP``
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OPTION TYPE:
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This configuration option is a boolean feature define.
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DEFAULT CONFIGURATION:
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If this configuration option is undefined, then the described feature is not
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enabled.
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DESCRIPTION:
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In case this configuration option is defined, then
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:ref:`Earliest Deadline First (EDF) SMP Scheduler <SchedulerSMPEDF>`
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algorithm is made available to the application.
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NOTES:
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This scheduler configuration option is an advanced configuration option.
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Think twice before you use it.
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This scheduler algorithm is only available when RTEMS is built with SMP
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support enabled.
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In case no explicit :ref:`clustered scheduler configuration
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<ConfigurationSchedulersClustered>` is present, then it is used as the
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scheduler for up to 32 processors.
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This scheduler algorithm is the default in SMP configurations if
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:ref:`CONFIGURE_MAXIMUM_PROCESSORS` is
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greater than one.
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.. index:: CONFIGURE_SCHEDULER_NAME
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.. _CONFIGURE_SCHEDULER_NAME:
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CONFIGURE_SCHEDULER_NAME
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------------------------
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CONSTANT:
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``CONFIGURE_SCHEDULER_NAME``
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DATA TYPE:
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RTEMS Name (``rtems_name``).
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RANGE:
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Any value.
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DEFAULT VALUE:
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The default name is
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- ``"MEDF"`` for the :ref:`EDF SMP Scheduler <SchedulerSMPEDF>`,
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- ``"MPA "`` for the :ref:`Arbitrary Processor Affinity Priority SMP Scheduler <SchedulerSMPPriorityAffinity>`,
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- ``"MPD "`` for the :ref:`Deterministic Priority SMP Scheduler <SchedulerSMPPriority>`,
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- ``"MPS "`` for the :ref:`Simple Priority SMP Scheduler <SchedulerSMPPrioritySimple>`,
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- ``"UCBS"`` for the :ref:`Uniprocessor CBS Scheduler <SchedulerCBS>`,
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- ``"UEDF"`` for the :ref:`Uniprocessor EDF Scheduler <SchedulerEDF>`,
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- ``"UPD "`` for the :ref:`Uniprocessor Deterministic Priority Scheduler <SchedulerPriority>`, and
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- ``"UPS "`` for the :ref:`Uniprocessor Simple Priority Scheduler <SchedulerPrioritySimple>`.
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DESCRIPTION:
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Schedulers can be identified via ``rtems_scheduler_ident``. The name of
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the scheduler is determined by the configuration.
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NOTES:
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This scheduler configuration option is an advanced configuration option.
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Think twice before you use it.
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.. index:: CONFIGURE_SCHEDULER_PRIORITY
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.. _CONFIGURE_SCHEDULER_PRIORITY:
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CONFIGURE_SCHEDULER_PRIORITY
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----------------------------
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CONSTANT:
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``CONFIGURE_SCHEDULER_PRIORITY``
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OPTION TYPE:
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This configuration option is a boolean feature define.
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DEFAULT CONFIGURATION:
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If this configuration option is undefined, then the described feature is not
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enabled.
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DESCRIPTION:
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In case this configuration option is defined, then
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:ref:`Deterministic Priority Scheduler <SchedulerPriority>`
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algorithm is made available to the application.
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NOTES:
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This scheduler configuration option is an advanced configuration option.
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Think twice before you use it.
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In case no explicit :ref:`clustered scheduler configuration
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<ConfigurationSchedulersClustered>` is present, then it is used as the
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scheduler for exactly one processor.
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This scheduler algorithm is the default when
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:ref:`CONFIGURE_MAXIMUM_PROCESSORS` is
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exactly one.
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The memory allocated for this scheduler depends on the
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:ref:`CONFIGURE_MAXIMUM_PRIORITY` configuration option.
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.. index:: CONFIGURE_SCHEDULER_PRIORITY_AFFINITY_SMP
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.. _CONFIGURE_SCHEDULER_PRIORITY_AFFINITY_SMP:
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CONFIGURE_SCHEDULER_PRIORITY_AFFINITY_SMP
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-----------------------------------------
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CONSTANT:
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``CONFIGURE_SCHEDULER_PRIORITY_AFFINITY_SMP``
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OPTION TYPE:
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This configuration option is a boolean feature define.
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DEFAULT CONFIGURATION:
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If this configuration option is undefined, then the described feature is not
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enabled.
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DESCRIPTION:
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In case this configuration option is defined, then
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:ref:`Arbitrary Processor Affinity SMP Scheduler <SchedulerSMPPriorityAffinity>`
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algorithm is made available to the application.
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NOTES:
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This scheduler configuration option is an advanced configuration option.
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Think twice before you use it.
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This scheduler algorithm is only available when RTEMS is built with SMP
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support enabled.
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In case no explicit :ref:`clustered scheduler configuration
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<ConfigurationSchedulersClustered>` is present, then it is used as the
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scheduler for up to 32 processors.
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The memory allocated for this scheduler depends on the
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:ref:`CONFIGURE_MAXIMUM_PRIORITY` configuration option.
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.. index:: CONFIGURE_SCHEDULER_PRIORITY_SMP
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.. _CONFIGURE_SCHEDULER_PRIORITY_SMP:
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CONFIGURE_SCHEDULER_PRIORITY_SMP
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--------------------------------
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CONSTANT:
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``CONFIGURE_SCHEDULER_PRIORITY_SMP``
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OPTION TYPE:
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This configuration option is a boolean feature define.
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DEFAULT CONFIGURATION:
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If this configuration option is undefined, then the described feature is not
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enabled.
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DESCRIPTION:
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In case this configuration option is defined, then
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:ref:`Deterministic Priority SMP Scheduler <SchedulerSMPPriority>`
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algorithm is made available to the application.
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NOTES:
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This scheduler configuration option is an advanced configuration option.
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Think twice before you use it.
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This scheduler algorithm is only available when RTEMS is built with SMP
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support enabled.
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In case no explicit :ref:`clustered scheduler configuration
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<ConfigurationSchedulersClustered>` is present, then it is used as the
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scheduler for up to 32 processors.
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The memory allocated for this scheduler depends on the
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:ref:`CONFIGURE_MAXIMUM_PRIORITY` configuration option.
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.. index:: CONFIGURE_SCHEDULER_SIMPLE
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.. _CONFIGURE_SCHEDULER_SIMPLE:
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CONFIGURE_SCHEDULER_SIMPLE
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--------------------------
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CONSTANT:
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``CONFIGURE_SCHEDULER_SIMPLE``
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OPTION TYPE:
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This configuration option is a boolean feature define.
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DEFAULT CONFIGURATION:
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If this configuration option is undefined, then the described feature is not
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enabled.
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DESCRIPTION:
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In case this configuration option is defined, then
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:ref:`Simple Priority Scheduler <SchedulerPrioritySimple>`
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algorithm is made available to the application.
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NOTES:
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This scheduler configuration option is an advanced configuration option.
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Think twice before you use it.
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In case no explicit :ref:`clustered scheduler configuration
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<ConfigurationSchedulersClustered>` is present, then it is used as the
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scheduler for exactly one processor.
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.. index:: CONFIGURE_SCHEDULER_SIMPLE_SMP
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.. _CONFIGURE_SCHEDULER_SIMPLE_SMP:
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CONFIGURE_SCHEDULER_SIMPLE_SMP
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------------------------------
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CONSTANT:
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``CONFIGURE_SCHEDULER_SIMPLE_SMP``
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OPTION TYPE:
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This configuration option is a boolean feature define.
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DEFAULT CONFIGURATION:
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If this configuration option is undefined, then the described feature is not
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enabled.
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DESCRIPTION:
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In case this configuration option is defined, then
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:ref:`Simple Priority SMP Scheduler <SchedulerSMPPrioritySimple>`
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algorithm is made available to the application.
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application.
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NOTES:
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This scheduler configuration option is an advanced configuration option.
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Think twice before you use it.
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This scheduler algorithm is only available when RTEMS is built with SMP
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support enabled.
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In case no explicit :ref:`clustered scheduler configuration
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<ConfigurationSchedulersClustered>` is present, then it is used as the
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scheduler for up to 32 processors.
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.. index:: CONFIGURE_SCHEDULER_USER
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.. _CONFIGURE_SCHEDULER_USER:
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CONFIGURE_SCHEDULER_USER
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------------------------
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CONSTANT:
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``CONFIGURE_SCHEDULER_USER``
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OPTION TYPE:
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This configuration option is a boolean feature define.
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DEFAULT CONFIGURATION:
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If this configuration option is undefined, then the described feature is not
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enabled.
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DESCRIPTION:
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In case this configuration option is defined, then the user must provide a
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scheduler algorithm to the application.
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NOTES:
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This scheduler configuration option is an advanced configuration option.
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Think twice before you use it.
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RTEMS allows the application to provide its own task/thread scheduling
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algorithm. In order to do this, one must define
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``CONFIGURE_SCHEDULER_USER`` to indicate the application provides its own
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scheduling algorithm. If ``CONFIGURE_SCHEDULER_USER`` is defined then the
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following additional macros must be defined:
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- ``CONFIGURE_SCHEDULER`` must be defined to a static definition of
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the scheduler data structures of the user scheduler.
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- ``CONFIGURE_SCHEDULER_TABLE_ENTRIES`` must be defined to a scheduler
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table entry initializer for the user scheduler.
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- ``CONFIGURE_SCHEDULER_USER_PER_THREAD`` must be defined to the type of
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the per-thread information of the user scheduler.
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At this time, the mechanics and requirements for writing a new scheduler
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are evolving and not fully documented. It is recommended that you look at
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the existing Deterministic Priority Scheduler in
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``cpukit/score/src/schedulerpriority*.c`` for guidance. For guidance on
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the configuration macros, please examine ``cpukit/sapi/include/confdefs.h``
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for how these are defined for the Deterministic Priority Scheduler.
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