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/**
* @file rtems/score/scheduleredf.h
*
* @brief Data Related to the Manipulation of Threads for the EDF Scheduler
*
* This include file contains all the constants and structures associated
* with the manipulation of threads for the EDF scheduler.
*/
/*
* Copryight (c) 2011 Petr Benes.
* Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#ifndef _RTEMS_SCORE_SCHEDULEREDF_H
#define _RTEMS_SCORE_SCHEDULEREDF_H
#include <rtems/score/priority.h>
#include <rtems/score/scheduler.h>
#include <rtems/score/schedulerpriority.h>
#include <rtems/score/rbtree.h>
#include <limits.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @defgroup ScoreSchedulerEDF EDF Scheduler
*
* @ingroup ScoreScheduler
*/
/**@{*/
/*
* Actually the EDF scheduler supports a maximum priority of
* 0x7fffffffffffffff, but the user API is limited to uint32_t or int for
* thread priorities. Ignore ILP64 targets for now.
*/
#define SCHEDULER_EDF_MAXIMUM_PRIORITY INT_MAX
/**
* Entry points for the Earliest Deadline First Scheduler.
*/
#define SCHEDULER_EDF_ENTRY_POINTS \
{ \
_Scheduler_EDF_Initialize, /* initialize entry point */ \
_Scheduler_EDF_Schedule, /* schedule entry point */ \
_Scheduler_EDF_Yield, /* yield entry point */ \
_Scheduler_EDF_Block, /* block entry point */ \
_Scheduler_EDF_Unblock, /* unblock entry point */ \
_Scheduler_EDF_Update_priority, /* update priority entry point */ \
_Scheduler_EDF_Map_priority, /* map priority entry point */ \
_Scheduler_EDF_Unmap_priority, /* unmap priority entry point */ \
SCHEDULER_OPERATION_DEFAULT_ASK_FOR_HELP \
_Scheduler_EDF_Node_initialize, /* node initialize entry point */ \
_Scheduler_default_Node_destroy, /* node destroy entry point */ \
_Scheduler_EDF_Release_job, /* new period of task */ \
_Scheduler_EDF_Cancel_job, /* cancel period of task */ \
_Scheduler_default_Tick, /* tick entry point */ \
_Scheduler_default_Start_idle /* start idle entry point */ \
SCHEDULER_OPERATION_DEFAULT_GET_SET_AFFINITY \
}
typedef struct {
/**
* @brief Basic scheduler context.
*/
Scheduler_Context Base;
/**
* Top of the ready queue.
*/
RBTree_Control Ready;
} Scheduler_EDF_Context;
/**
* @brief Scheduler node specialization for EDF schedulers.
*/
typedef struct {
/**
* @brief Basic scheduler node.
*/
Scheduler_Node Base;
/**
* Pointer to corresponding Thread Control Block.
*/
Thread_Control *thread;
/**
* Rbtree node related to this thread.
*/
RBTree_Node Node;
/**
* @brief The thread priority used by this scheduler instance in case no job
* is released.
*/
Priority_Control background_priority;
/**
* @brief The thread priority currently used by this scheduler instance.
*/
Priority_Control current_priority;
} Scheduler_EDF_Node;
/**
* @brief Initialize EDF scheduler.
*
* This routine initializes the EDF scheduler.
*
* @param[in] scheduler The scheduler instance.
*/
void _Scheduler_EDF_Initialize( const Scheduler_Control *scheduler );
/**
* @brief Removes thread from ready queue.
*
* This routine removes @a the_thread from the scheduling decision,
* that is, removes it from the ready queue. It performs
* any necessary scheduling operations including the selection of
* a new heir thread.
*
* @param[in] scheduler The scheduler instance.
* @param[in] the_thread is the thread to be blocked.
*/
void _Scheduler_EDF_Block(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
/**
* @brief Sets the heir thread to be the next ready thread
* in the rbtree ready queue.
*
* This kernel routine sets the heir thread to be the next ready thread
* in the rbtree ready queue.
*
* @param[in] scheduler The scheduler instance.
* @param[in] the_thread being scheduled.
*/
void _Scheduler_EDF_Schedule(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
/**
* @brief Initializes an EDF specific scheduler node of @a the_thread.
*
* @param[in] scheduler The scheduler instance.
* @param[in] node being initialized.
* @param[in] the_thread the thread of the node.
* @param[in] priority The thread priority.
*/
void _Scheduler_EDF_Node_initialize(
const Scheduler_Control *scheduler,
Scheduler_Node *node,
Thread_Control *the_thread,
Priority_Control priority
);
/**
* @brief Adds @a the_thread to the scheduling decision.
*
* This routine adds @a the_thread to the scheduling decision, that is,
* adds it to the ready queue and updates any appropriate scheduling
* variables, for example the heir thread.
*
* @param[in] scheduler The scheduler instance.
* @param[in] the_thread will be unblocked.
*/
Scheduler_Void_or_thread _Scheduler_EDF_Unblock(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
Scheduler_Void_or_thread _Scheduler_EDF_Update_priority(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
Priority_Control _Scheduler_EDF_Map_priority(
const Scheduler_Control *scheduler,
Priority_Control priority
);
Priority_Control _Scheduler_EDF_Unmap_priority(
const Scheduler_Control *scheduler,
Priority_Control priority
);
/**
* @brief invoked when a thread wishes to voluntarily
* transfer control of the processor to another thread
* with equal deadline.
*
* This routine is invoked when a thread wishes to voluntarily
* transfer control of the processor to another thread in the queue with
* equal deadline. This does not have to happen very often.
*
* This routine will remove the specified THREAD from the ready queue
* and place it back. The rbtree ready queue is responsible for FIFO ordering
* in such a case.
*
* @param[in] scheduler The scheduler instance.
* @param[in,out] the_thread The yielding thread.
*/
Scheduler_Void_or_thread _Scheduler_EDF_Yield(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
Thread_Control *_Scheduler_EDF_Release_job(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
uint64_t deadline
);
Thread_Control *_Scheduler_EDF_Cancel_job(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
#ifdef __cplusplus
}
#endif
/**@}*/
#endif
/* end of include file */
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