The Ravenscar Profile
Author: JTC1/SC22/WG9/ARG, by Randall Brukardt, ARG Editor

Ada Reference Manual — Legal Information

# D.13 The Ravenscar Profile

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

#### Legality Rules

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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

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The usage profile Ravenscar is equivalent to the following set of pragmas:
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pragma Task_Dispatching_Policy (FIFO_Within_Priorities);
pragma Locking_Policy (Ceiling_Locking);
pragma Detect_Blocking;
pragma Restrictions (
No_Abort_Statements,
No_Dynamic_Attachment,
No_Dynamic_Priorities,
No_Implicit_Heap_Allocations,
No_Local_Protected_Objects,
No_Local_Timing_Events,
No_Protected_Type_Allocators,
No_Relative_Delay,
No_Requeue_Statements,
No_Select_Statements,
No_Specific_Termination_Handlers,
No_Task_Allocators,
No_Task_Hierarchy,
No_Task_Termination,
Simple_Barriers,
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

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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

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On a multiprocessor system, an implementation should support a fully partitioned approach. Each processor should have separate and disjoint ready queues.
NOTES
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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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