Strong APA Scheduler

This group contains the Strong APA Scheduler implementation. More...

Files
file	schedulerstrongapa.h
	This header file provides the interfaces of the Strong APA Scheduler.
file	schedulerstrongapa.c
	This source file contains the implementation of _Scheduler_strong_APA_Add_processor(), _Scheduler_strong_APA_Allocate_processor(), _Scheduler_strong_APA_Ask_for_help(), _Scheduler_strong_APA_Block(), _Scheduler_strong_APA_Do_ask_for_help(), _Scheduler_strong_APA_Do_enqueue(), _Scheduler_strong_APA_Do_set_affinity(), _Scheduler_strong_APA_Do_update(), _Scheduler_strong_APA_Enqueue(), _Scheduler_strong_APA_Enqueue_scheduled(), _Scheduler_strong_APA_Extract_from_ready(), _Scheduler_strong_APA_Extract_from_scheduled(), _Scheduler_strong_APA_Find_highest_ready(), _Scheduler_strong_APA_Get_highest_ready(), _Scheduler_strong_APA_Get_lowest_reachable(), _Scheduler_strong_APA_Get_lowest_scheduled(), _Scheduler_strong_APA_Has_ready(), _Scheduler_strong_APA_Initialize(), _Scheduler_strong_APA_Insert_ready(), _Scheduler_strong_APA_Move_from_ready_to_scheduled(), _Scheduler_strong_APA_Move_from_scheduled_to_ready(), _Scheduler_strong_APA_Node_initialize(), _Scheduler_strong_APA_Reconsider_help_request(), _Scheduler_strong_APA_Register_idle(), _Scheduler_strong_APA_Remove_processor(), _Scheduler_strong_APA_Set_affinity(), _Scheduler_strong_APA_Set_scheduled(), _Scheduler_strong_APA_Start_idle(), _Scheduler_strong_APA_Unblock(), _Scheduler_strong_APA_Update_priority(), _Scheduler_strong_APA_Withdraw_node(), _Scheduler_strong_APA_Make_sticky(), _Scheduler_strong_APA_Clean_sticky(), and _Scheduler_strong_APA_Yield().

Data Structures
struct	Scheduler_strong_APA_Node
	Scheduler node specialization for Strong APA schedulers. More...
struct	Scheduler_strong_APA_CPU
	CPU related variables and a CPU_Control to implement BFS. More...
struct	Scheduler_strong_APA_Context
	Scheduler context and node definition for Strong APA scheduler. More...

Macros
#define	SCHEDULER_STRONG_APA_MAXIMUM_PRIORITY   255
#define	SCHEDULER_STRONG_APA_ENTRY_POINTS
	Entry points for the Strong APA Scheduler.

Functions
void	_Scheduler_strong_APA_Initialize (const Scheduler_Control *scheduler)
	Initializes the scheduler.
void	_Scheduler_strong_APA_Node_initialize (const Scheduler_Control *scheduler, Scheduler_Node *node, Thread_Control *the_thread, Priority_Control priority)
	Initializes the node with the given priority.
void	_Scheduler_strong_APA_Block (const Scheduler_Control *scheduler, Thread_Control *the_thread, Scheduler_Node *node)
	Blocks the thread.
void	_Scheduler_strong_APA_Unblock (const Scheduler_Control *scheduler, Thread_Control *the_thread, Scheduler_Node *node)
	Unblocks the thread.
void	_Scheduler_strong_APA_Update_priority (const Scheduler_Control *scheduler, Thread_Control *the_thread, Scheduler_Node *node)
	Updates the priority of the node.
bool	_Scheduler_strong_APA_Ask_for_help (const Scheduler_Control *scheduler, Thread_Control *the_thread, Scheduler_Node *node)
	Asks for help.
void	_Scheduler_strong_APA_Reconsider_help_request (const Scheduler_Control *scheduler, Thread_Control *the_thread, Scheduler_Node *node)
	Reconsiders help request.
void	_Scheduler_strong_APA_Withdraw_node (const Scheduler_Control *scheduler, Thread_Control *the_thread, Scheduler_Node *node, Thread_Scheduler_state next_state)
	Withdraws the node.
void	_Scheduler_strong_APA_Make_sticky (const Scheduler_Control *scheduler, Thread_Control *the_thread, Scheduler_Node *node)
	Makes the node sticky.
void	_Scheduler_strong_APA_Clean_sticky (const Scheduler_Control *scheduler, Thread_Control *the_thread, Scheduler_Node *node)
	Cleans the sticky property from the node.
void	_Scheduler_strong_APA_sticky (const Scheduler_Control *scheduler, Thread_Control *the_thread, Scheduler_Node *node)
	Cleans the sticky property from the node.
void	_Scheduler_strong_APA_Add_processor (const Scheduler_Control *scheduler, Thread_Control *idle)
	Adds the idle thread to a processor.
Thread_Control *	_Scheduler_strong_APA_Remove_processor (const Scheduler_Control *scheduler, struct Per_CPU_Control *cpu)
	Removes an idle thread from the given cpu.
void	_Scheduler_strong_APA_Yield (const Scheduler_Control *scheduler, Thread_Control *the_thread, Scheduler_Node *node)
	Performs a yield operation.
void	_Scheduler_strong_APA_Start_idle (const Scheduler_Control *scheduler, Thread_Control *idle, struct Per_CPU_Control *cpu)
	Starts an idle thread.
Status_Control	_Scheduler_strong_APA_Set_affinity (const Scheduler_Control *scheduler, Thread_Control *thread, Scheduler_Node *node_base, const Processor_mask *affinity)
	Sets the affinity .

Detailed Description

This group contains the Strong APA Scheduler implementation.

This is an implementation of the Strong APA scheduler defined by Cerqueira et al. in Linux's Processor Affinity API, Refined: Shifting Real-Time Tasks Towards Higher Schedulability.

The scheduled and ready nodes are accessed via the Scheduler_strong_APA_Context::Ready which helps in backtracking when a node which is executing on a CPU gets blocked. New node is allocated to the cpu by checking all the executing nodes in the affinity set of the node and the subsequent nodes executing on the processors in its affinity set.

Macro Definition Documentation

SCHEDULER_STRONG_APA_ENTRY_POINTS

#define SCHEDULER_STRONG_APA_ENTRY_POINTS

Value:

  { \
    _Scheduler_strong_APA_Initialize, \
    _Scheduler_default_Schedule, \
    _Scheduler_strong_APA_Yield, \
    _Scheduler_strong_APA_Block, \
    _Scheduler_strong_APA_Unblock, \
    _Scheduler_strong_APA_Update_priority, \
    _Scheduler_default_Map_priority, \
    _Scheduler_default_Unmap_priority, \
    _Scheduler_strong_APA_Ask_for_help, \
    _Scheduler_strong_APA_Reconsider_help_request, \
    _Scheduler_strong_APA_Withdraw_node, \
    _Scheduler_strong_APA_Make_sticky, \
    _Scheduler_strong_APA_Clean_sticky, \
    _Scheduler_default_Pin_or_unpin_not_supported, \
    _Scheduler_default_Pin_or_unpin_not_supported, \
    _Scheduler_strong_APA_Add_processor, \
    _Scheduler_strong_APA_Remove_processor, \
    _Scheduler_strong_APA_Node_initialize, \
    _Scheduler_default_Node_destroy, \
    _Scheduler_default_Release_job, \
    _Scheduler_default_Cancel_job, \
    _Scheduler_strong_APA_Start_idle, \
    _Scheduler_strong_APA_Set_affinity \
  }

Entry points for the Strong APA Scheduler.

Function Documentation

_Scheduler_strong_APA_Add_processor()

void _Scheduler_strong_APA_Add_processor	(	const Scheduler_Control *	scheduler,
		Thread_Control *	idle
	)

Adds the idle thread to a processor.

Parameters

	scheduler	The scheduler control instance.
[in,out]	The	idle thread to add to the processor.

_Scheduler_strong_APA_Ask_for_help()

bool _Scheduler_strong_APA_Ask_for_help	(	const Scheduler_Control *	scheduler,
		Thread_Control *	the_thread,
		Scheduler_Node *	node
	)

Asks for help.

Parameters

scheduler	The scheduler control instance.
the_thread	The thread that asks for help.
node	The node of the_thread.

Return values

true	The request for help was successful.
false	The request for help was not successful.

_Scheduler_strong_APA_Block()

void _Scheduler_strong_APA_Block	(	const Scheduler_Control *	scheduler,
		Thread_Control *	the_thread,
		Scheduler_Node *	node
	)

Blocks the thread.

Parameters

	scheduler	The scheduler control instance.
[in,out]	the_thread	The thread to block.
[in,out]	node	The node of the thread to block.

_Scheduler_strong_APA_Clean_sticky()

void _Scheduler_strong_APA_Clean_sticky	(	const Scheduler_Control *	scheduler,
		Thread_Control *	the_thread,
		Scheduler_Node *	node
	)

Cleans the sticky property from the node.

Parameters

	scheduler	is the scheduler of the node.
[in,out]	the_thread	is the thread owning the node.
[in,out]	node	is the scheduler node to clean the sticky property.

_Scheduler_strong_APA_Initialize()

void _Scheduler_strong_APA_Initialize

(

const Scheduler_Control *

scheduler

)

Initializes the scheduler.

Parameters

scheduler

The scheduler to initialize.

_Scheduler_strong_APA_Make_sticky()

void _Scheduler_strong_APA_Make_sticky	(	const Scheduler_Control *	scheduler,
		Thread_Control *	the_thread,
		Scheduler_Node *	node
	)

Makes the node sticky.

Parameters

	scheduler	is the scheduler of the node.
[in,out]	the_thread	is the thread owning the node.
[in,out]	node	is the scheduler node to make sticky.

Parameters

	scheduler	is the scheduler of the node.
[in,out]	the_thread	is the thread owning the node.
[in,out]	node	is the scheduler node to make sticky.

_Scheduler_strong_APA_Node_initialize()

void _Scheduler_strong_APA_Node_initialize	(	const Scheduler_Control *	scheduler,
		Scheduler_Node *	node,
		Thread_Control *	the_thread,
		Priority_Control	priority
	)

Initializes the node with the given priority.

Parameters

	scheduler	The scheduler control instance.
[out]	node	The node to initialize.
	the_thread	The thread of the node to initialize.
	priority	The priority for node.

_Scheduler_strong_APA_Reconsider_help_request()

void _Scheduler_strong_APA_Reconsider_help_request	(	const Scheduler_Control *	scheduler,
		Thread_Control *	the_thread,
		Scheduler_Node *	node
	)

Reconsiders help request.

Parameters

	scheduler	The scheduler control instance.
	the_thread	The thread to reconsider the help request of.
[in,out]	node	The node of the_thread

_Scheduler_strong_APA_Remove_processor()

Thread_Control * _Scheduler_strong_APA_Remove_processor	(	const Scheduler_Control *	scheduler,
		struct Per_CPU_Control *	cpu
	)

Removes an idle thread from the given cpu.

Parameters

scheduler	The scheduler instance.
cpu	The cpu control to remove from scheduler.

Returns

The idle thread of the processor.

_Scheduler_strong_APA_Set_affinity()

Status_Control _Scheduler_strong_APA_Set_affinity	(	const Scheduler_Control *	scheduler,
		Thread_Control *	thread,
		Scheduler_Node *	node_base,
		const Processor_mask *	affinity
	)

Sets the affinity .

Parameters

	scheduler	The scheduler control instance.
	the_thread	The thread to yield.
[in,out]	node	The node of the_thread.

_Scheduler_strong_APA_Start_idle()

void _Scheduler_strong_APA_Start_idle	(	const Scheduler_Control *	scheduler,
		Thread_Control *	idle,
		struct Per_CPU_Control *	cpu
	)

Starts an idle thread.

Parameters

	scheduler	The scheduler instance.
[in,out]	the_thread	An idle thread.
	cpu	The cpu for the operation.

_Scheduler_strong_APA_sticky()

void _Scheduler_strong_APA_sticky	(	const Scheduler_Control *	scheduler,
		Thread_Control *	the_thread,
		Scheduler_Node *	node
	)

Cleans the sticky property from the node.

Parameters

	scheduler	is the scheduler of the node.
[in,out]	the_thread	is the thread owning the node.
[in,out]	node	is the scheduler node to clean the sticky property.

_Scheduler_strong_APA_Unblock()

void _Scheduler_strong_APA_Unblock	(	const Scheduler_Control *	scheduler,
		Thread_Control *	the_thread,
		Scheduler_Node *	node
	)

Unblocks the thread.

Parameters

	scheduler	The scheduler control instance.
[in,out]	the_thread	The thread to unblock.
[in,out]	node	The node of the thread to unblock.

_Scheduler_strong_APA_Update_priority()

void _Scheduler_strong_APA_Update_priority	(	const Scheduler_Control *	scheduler,
		Thread_Control *	the_thread,
		Scheduler_Node *	node
	)

Updates the priority of the node.

Parameters

	scheduler	The scheduler control instance.
	the_thread	The thread for the operation.
[in,out]	node	The node to update the priority of.

_Scheduler_strong_APA_Withdraw_node()

void _Scheduler_strong_APA_Withdraw_node	(	const Scheduler_Control *	scheduler,
		Thread_Control *	the_thread,
		Scheduler_Node *	node,
		Thread_Scheduler_state	next_state
	)

Withdraws the node.

Parameters

	scheduler	The scheduler control instance.
[in,out]	the_thread	The thread to change the state to next_state.
[in,out]	node	The node to withdraw.
	next_state	The next state for the_thread.

_Scheduler_strong_APA_Yield()

void _Scheduler_strong_APA_Yield	(	const Scheduler_Control *	scheduler,
		Thread_Control *	the_thread,
		Scheduler_Node *	node
	)

Performs a yield operation.

Parameters

	scheduler	The scheduler control instance.
	the_thread	The thread to yield.
[in,out]	node	The node of the_thread.