The Task Dispatching Model Go to the first , previous , next , last section, table of contents . The task dispatching model specifies preemptive scheduling, based on conceptual priority-ordered ready queues. Processors are allocated to tasks based on each task's active priority. It is implementation defined whether, on a multiprocessor, a task that is waiting for access to a protected object keeps its processor busy.
Task dispatching is the process by which one ready task is selected for execution on a processor.
This selection is done at certain points during the execution of a task called task dispatching points. A task reaches a task dispatching point whenever it becomes blocked, and whenever it becomes ready. Entries and Accept Statements , and task termination are task dispatching points for the executing task. Other task dispatching points are defined throughout this Annex. Task dispatching policies are specified in terms of conceptual ready queues, task states, and task preemption.