From a60c5b4b3ed683b1ca13149309bc84de84615a71 Mon Sep 17 00:00:00 2001 From: Sebastian Huber Date: Tue, 19 Jan 2021 07:24:35 +0100 Subject: c-user: Generate clock manager documentation The documentation is a consolidation of the comments in Doxygen markup and the documentation sources in Sphinx markup. The documentation was transfered to interface specification items. The documentation source files were generated from the items by a script. Update #3993. --- c-user/glossary.rst | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) (limited to 'c-user/glossary.rst') diff --git a/c-user/glossary.rst b/c-user/glossary.rst index 65e1fd7..8aa1266 100644 --- a/c-user/glossary.rst +++ b/c-user/glossary.rst @@ -121,6 +121,39 @@ Glossary of elements. It differs from an array in that it is not limited to a predefined size. + Clock Driver + The Clock Driver is a driver which provides the :term:`clock tick` and a + time counter. The time counter is used to drive the :term:`CLOCK_REALTIME` + and :term:`CLOCK_MONOTONIC`. The Clock Driver can be initialized by the + application with the :ref:`CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER` and + :ref:`CONFIGURE_MICROSECONDS_PER_TICK` application configuration options. + + clock tick + The clock tick is a coarse time measure provided by RTEMS. The + :term:`Clock Driver` emits clock ticks at rate specified by the + :ref:`CONFIGURE_MICROSECONDS_PER_TICK` application configuration option. In + contrast to :term:`CLOCK_REALTIME` and :term:`CLOCK_MONOTONIC`, the clock + tick rate is not affected by incremental adjustments. + + CLOCK_MONOTONIC + The CLOCK_MONOTONIC is a clock provided by RTEMS which measures the time + since an unspecified starting point. In contrast to :term:`CLOCK_REALTIME`, + this clock cannot be set. It may be affected by incremental adjustments for + example carried out by the :term:`NTP` or the use of a :term:`PPS` signal. + See also :term:`CLOCK_REALTIME`, :term:`clock tick`, and + :term:`Clock Driver`. + + CLOCK_REALTIME + The CLOCK_REALTIME is a clock provided by RTEMS which measures the real time + (also known as wall-clock time). It is defined by :term:`POSIX`. In + particular, every day is treated as if it contains exactly 86400 seconds and + leap seconds are ignored. This clock can be set by the application which may + result in time jumps. It may be affected by incremental adjustments for + example carried out by the :term:`NTP` or the use of a :term:`PPS` signal. + RTEMS can represent time points of this clock in nanoseconds ranging from + 1988-01-01T00:00:00.000000000Z to 2514-05-31T01:53:03.999999999Z. See also + :term:`CLOCK_MONOTONIC`, :term:`clock tick`, and :term:`Clock Driver`. + cluster We have clustered scheduling in case the set of processors of a system is partitioned into non-empty pairwise disjoint subsets. These subsets are @@ -458,6 +491,10 @@ Glossary non-existent The state occupied by an uncreated or deleted task. + NTP + This term is an acronym for + `Network Time Protocol `_. + NUMA This term is an acronym for Non-Uniform Memory Access. @@ -527,9 +564,17 @@ Glossary A term used to describe the ease with which software can be rehosted on another computer. + POSIX + This term is an acronym for + `Portable Operating System Interface `_. + posting The act of sending an event, message, semaphore, or signal to a task. + PPS + This term is an acronym for + `Pulse-Per-Second `_. + preempt The act of forcing a task to relinquish the processor and dispatching to another task. @@ -650,6 +695,10 @@ Glossary RTEMS This term is an acronym for Real-Time Executive for Multiprocessor Systems. + RTEMS epoch + The RTEMS epoch is a point in time. It is 1988-01-01T00:00:00Z in + `ISO 8601 `_ time format. + running The state of a rate monotonic timer while it is being used to delineate a period. The timer exits this state by either expiring or being canceled. @@ -910,6 +959,10 @@ Glossary TTAS This term is an acronym for Test and Test-And-Set. + Unix epoch + The Unix epoch is a point in time. It is 1970-01-01T00:00:00Z in + `ISO 8601 `_ time format. + User Extension Table A table which contains the entry points for each user extensions. -- cgit v1.2.3