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D.13 The Ravenscar Profile

This subclause defines the Ravenscar profile.
Paragraphs 2 and 3 were moved to 13.12, “Pragma Restrictions and Pragma Profile”. 

Legality Rules

The profile_identifier Ravenscar is a usage profile (see 13.12). For usage profile Ravenscar, there shall be no profile_pragma_argument_associations.

Static Semantics

The usage profile Ravenscar is equivalent to the following set of pragmas:
pragma Task_Dispatching_Policy (FIFO_Within_Priorities);
pragma Locking_Policy (Ceiling_Locking);
pragma Detect_Blocking;
pragma Restrictions (
              Max_Entry_Queue_Length => 1,
              Max_Protected_Entries => 1,
              Max_Task_Entries => 0,
              No_Dependence => Ada.Asynchronous_Task_Control,
              No_Dependence => Ada.Calendar,
              No_Dependence => Ada.Execution_Time.Group_Budgets,
              No_Dependence => Ada.Execution_Time.Timers,
              No_Dependence => Ada.Task_Attributes,
              No_Dependence => System.Multiprocessors.Dispatching_Domains);
Paragraph 7 was deleted.

Implementation Requirements

A task shall only be on the ready queues of one processor, and the processor to which a task belongs shall be defined statically. Whenever a task running on a processor reaches a task dispatching point, it goes back to the ready queues of the same processor. A task with a CPU value of Not_A_Specific_CPU will execute on an implementation defined processor. A task without a CPU aspect will activate and execute on the same processor as its activating task. 

Implementation Advice

On a multiprocessor system, an implementation should support a fully partitioned approach. Each processor should have separate and disjoint ready queues.
42  The effect of the Max_Entry_Queue_Length => 1 restriction applies only to protected entry queues due to the accompanying restriction of Max_Task_Entries => 0. 

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