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/*
* Copyright (C) 2014 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License. See the file LICENSE in the top level directory for more
* details.
*/
/**
* @defgroup core_sched Scheduler
* @ingroup core
* @brief The RIOT scheduler
* @{
*
* @file sched.h
* @brief Scheduler API definion
*
* @author Kaspar Schleiser <kaspar@schleiser.de>
*/
#ifndef _SCHEDULER_H
#define _SCHEDULER_H
#include <stddef.h>
#include "bitarithm.h"
#include "tcb.h"
#include "attributes.h"
#define MAXTHREADS 32 /**< the maximum number of threads to be scheduled */
/**
* @def SCHED_PRIO_LEVELS
* @brief The number of thread priority levels
*/
#if ARCH_32_BIT
#define SCHED_PRIO_LEVELS 32
#else
#define SCHED_PRIO_LEVELS 16
#endif
/**
* @brief Triggers the scheduler to schedule the next thread
*/
void sched_run(void);
/**
* @brief Set the status of the specified process
*
* @param[in] process Pointer to the thread control block of the
* targeted process
* @param[in] status The new status of this thread
*/
void sched_set_status(tcb_t *process, unsigned int status);
/**
* @brief Compare thread priorities and yield() (or set
* sched_context_switch_request if inISR()) when other_prio is higher
* (has a lower value) than the current thread's priority
*
* @param[in] other_prio The priority of the target thread
*/
void sched_switch(uint16_t other_prio);
/**
* @brief Call context switching at thread exit
*/
NORETURN void cpu_switch_context_exit(void);
/**
* Flag indicating whether a context switch is necessary after handling an
* interrupt. Supposed to be set in an ISR.
*/
extern volatile unsigned int sched_context_switch_request;
/**
* Thread table
*/
extern volatile tcb_t *sched_threads[MAXTHREADS];
/**
* Currently active thread
*/
extern volatile tcb_t *sched_active_thread;
/**
* Number of running (non-terminated) threads
*/
extern volatile int sched_num_threads;
/**
* Process ID of active thread
*/
extern volatile int sched_active_pid;
/**
* List of runqueues per priority level
*/
extern clist_node_t *runqueues[SCHED_PRIO_LEVELS];
#if SCHEDSTATISTICS
/**
* Scheduler statistics
*/
typedef struct {
unsigned int laststart; /**< Time stamp of the last time this thread was
scheduled to run */
unsigned int schedules; /**< How often the thread was scheduled to run */
unsigned long runtime_ticks; /**< The total runtime of this thread in ticks */
} schedstat;
/**
* Thread statistics table
*/
extern schedstat sched_pidlist[MAXTHREADS];
/**
* @brief Register a callback that will be called on every scheduler run
*
* @param[in] callback The callback functions the will be called
*/
void sched_register_cb(void (*callback)(uint32_t, uint32_t));
#endif
#endif // _SCHEDULER_H
/** @} */