--- c-user/glossary.rst | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+)
diff --git a/c-user/glossary.rst b/c-user/glossary.rst index 86350a8..691ba52 100644 --- a/c-user/glossary.rst +++ b/c-user/glossary.rst @@ -1,5 +1,6 @@ .. SPDX-License-Identifier: CC-BY-SA-4.0 +.. Copyright (C) 2020 Richi Dubey (richidu...@gmail.com) .. Copyright (C) 2017, 2019 embedded brains GmbH (http://www.embedded-brains.de) .. Copyright (C) 1988, 1998 On-Line Applications Research Corporation (OAR) @@ -16,6 +17,13 @@ Glossary A term used to describe an object which has been created by an application. + APA + This term is an acronym for Arbitrary Processor Affinity. + APA schedulers allow a thread to have an arbitrary affinity to + a processor set, rather than a restricted mapping to only one + processor of the set or the ability to run on all processors of + the set. It has two variants, :term:`Weak APA` and :term:`Strong APA` + aperiodic task A task which must execute only at irregular intervals and has only a soft deadline. @@ -777,6 +785,19 @@ Glossary :term:`return value` to indicate a successful operation or error conditions. + Strong APA + Strong APA is a specialization of :term:`APA`. + Whenever a :term:`thread` becomes ready for execution, schedulers which + implement strong APA recursively search for a processor in the thread's + affinity set, followed by the processors in the affinity set of threads + that are assigned the processor present in the ready thread's affinity set. + This is done to find a thread to processor mapping that does not violate the + priority ordering and to provide a schedule with a higher total priority of + the threads scheduled. + Similar analysis is done when a thread finishes its execution. + + See also :cite:`Cerqueira:2014:LPA`. + suspend A term used to describe a task that is not competing for the CPU because it has had a ``rtems_task_suspend`` directive. @@ -905,6 +926,16 @@ Glossary Message queues, regions, and semaphores have a wait queue associated with them. + Weak APA + Weak APA is a specialization of :term:`APA`. This refers to Linux's push and + pull implementation of APA model. On the arrival of a thread, the thread is + scheduled when a processor in its affinity set is idle or a processor in its + affinity set is executing a thread which is at a lower priority. + Unlike :term:`Strong APA`, no thread is migrated from its processor to find + a thread to processor mapping. + + See also :cite:`Cerqueira:2014:LPA`. + YAML This term is an acronym for `YAML Ain't Markup Language <https://yaml.org/>`_. -- 2.17.1 _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
