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Diffstat (limited to 'doc/user/schedule.t')
| -rw-r--r-- | doc/user/schedule.t | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/doc/user/schedule.t b/doc/user/schedule.t index 457ca57900..29f81b49d5 100644 --- a/doc/user/schedule.t +++ b/doc/user/schedule.t @@ -13,6 +13,9 @@ @chapter Scheduling Concepts +@cindex scheduling +@cindex task scheduling + @section Introduction The concept of scheduling in real-time systems @@ -49,6 +52,8 @@ events. @section Scheduling Mechanisms +@cindex scheduling mechanisms + RTEMS provides four mechanisms which allow the user to impact the task scheduling process: @@ -74,6 +79,8 @@ description. @subsection Task Priority and Scheduling +@cindex task priority + The most significant of these mechanisms 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 @@ -95,6 +102,8 @@ to a task.} @subsection Preemption +@cindex preemption + Another way the user can alter the basic scheduling algorithm is by manipulating the preemption mode flag (@code{@value{RPREFIX}PREEMPT_MASK}) of individual tasks. If preemption is disabled @@ -108,6 +117,9 @@ control of the processor. @subsection Timeslicing +@cindex timeslicing +@cindex round robin scheduling + Timeslicing or round-robin scheduling is an additional method which can be used to alter the basic scheduling algorithm. Like preemption, timeslicing is specified @@ -127,6 +139,8 @@ entire timeslice. @subsection Manual Round-Robin +@cindex 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 @code{@value{DIRPREFIX}task_wake_after} @@ -139,6 +153,8 @@ of the processor. @subsection Dispatching Tasks +@cindex dispatching + The dispatcher is the RTEMS component responsible for allocating the processor to a ready task. In order to allocate the processor to one task, it must be deallocated or retrieved @@ -167,6 +183,8 @@ the last task to utilize the coprocessor. @section Task State Transitions +@cindex task state transitions + Tasks in an RTEMS system must always be in one of the five allowable task states. These states are: executing, ready, blocked, dormant, and non-existent. |