sched.c File Reference

management of the scheduling data More...

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Functions

int sched_init (void)

initalize arrays

int sched_index (int prio)

static int get_max_dp (int prio, sched_t *new_)

Get max blocking time due to non-preemption for a thread.

int sched_response_time (sched_t *sched, int from, sched_t *new_)

Get the response time of the thread s.

int sched_free (int pos)

Free an element at the given position.

int sched_prepare_free (int pos)

Ask the watcher of a sched-entry to stop and wait for its readiness.

void lock_scheds (void)

void unlock_scheds (void)

Variables

int sched_cur_threads

int sched_max_threads

sched_t ** scheds

l4semaphore_t scheds_lock = L4SEMAPHORE_UNLOCKED

Detailed Description

management of the scheduling data

Date:: 09/04/2004

Author:: Jork Loeser <jork.loeser@inf.tu-dresden.de>

Definition in file sched.c.

Function Documentation

static int get_max_dp	(	int	prio,
		sched_t *	new_
	)			`[static]`

Get max blocking time due to non-preemption for a thread.

Parameters:

	prio	prio of the thread to analyze
	new_	optional additional thread, not in scheds yet

Returns:: max blocking time due to non-preemption by lower-prioritized threads

This function gets the max blocking time due to non-preemption for a thread of the given priority. Note that only threads with *lower* priority are taken into account, as others do not lead to blocking due to non-preemption but to normal preemption. Normal preemption is handled elsewhere.

Definition at line 78 of file sched.c.

References is_dp(), sched_t::prio, sched_cur_threads, and sched_t::wcet.

Referenced by sched_response_time().

void lock_scheds ( void )

Definition at line 175 of file sched.c.

References scheds_lock.

Referenced by l4cpu_reserve_add_component(), l4cpu_reserve_change_component(), l4cpu_reserve_delayed_preempt_component(), l4cpu_reserve_delete_task_component(), l4cpu_reserve_delete_thread_component(), monitor_start(), monitor_thread_dl(), and watch_hit_ts().

int sched_free ( int pos )

Free an element at the given position.

Definition at line 139 of file sched.c.

References sched_t::dl_hist, sched_t::name, sched_cur_threads, sched_t::watch, and sched_t::watcher.

Referenced by l4cpu_reserve_delete_task_component(), and l4cpu_reserve_delete_thread_component().

int sched_index ( int prio )

Definition at line 41 of file sched.c.

References sched_cur_threads.

Referenced by l4cpu_reserve_add_component(), l4cpu_reserve_change_component(), and l4cpu_reserve_delayed_preempt_component().

int sched_init ( void )

initalize arrays

Return values:

	0	OK
	-L4_ENOMEM	out of memory

Definition at line 29 of file sched.c.

References sched_max_threads.

Referenced by main().

int sched_prepare_free ( int pos )

Ask the watcher of a sched-entry to stop and wait for its readiness.

Definition at line 159 of file sched.c.

References sched_cur_threads, sched_t::watcher, and sched_t::watcher_end_sem.

Referenced by l4cpu_reserve_delete_task_component(), and l4cpu_reserve_delete_thread_component().

int sched_response_time	(	sched_t *	sched,
		int	from,
		sched_t *	new_
	)

Get the response time of the thread s.

we do response-time analysis based on the wcet of the higher-prioritized threads with (period T, wcet C) (sometimes called time-demand analysis): Iterative proces: r_j+1 = sum_i { ceil(r_j/T_i)*C_i } until fixpoint is found

Parameters:

	sched	contains sched params. If found in scheds, it is not included again
	from	consider all threads at and above pos
	new_	a new thread, that is not in scheds yet, but has higher prio than s. maybe 0.

Return values:

	>0	response time, <=deadline
	-1	respones time would be>deadline

Definition at line 109 of file sched.c.

References sched_t::deadline, get_max_dp(), is_dp(), sched_t::period, sched_t::prio, sched_cur_threads, and sched_t::wcet.

Referenced by l4cpu_reserve_add_component(), l4cpu_reserve_change_component(), l4cpu_reserve_delayed_preempt_component(), and l4cpu_reserve_time_demand_component().

void unlock_scheds ( void )

Definition at line 179 of file sched.c.

References scheds_lock.

Referenced by l4cpu_reserve_add_component(), l4cpu_reserve_change_component(), l4cpu_reserve_delayed_preempt_component(), l4cpu_reserve_delete_task_component(), l4cpu_reserve_delete_thread_component(), monitor_start(), monitor_thread_dl(), and watch_hit_ts().

Variable Documentation

int sched_max_threads

Definition at line 20 of file sched.c.

Referenced by l4cpu_reserve_add_component(), l4cpu_reserve_delayed_preempt_component(), main(), and sched_init().

sched_t** scheds

Definition at line 21 of file sched.c.

Referenced by l4cpu_reserve_add_component(), l4cpu_reserve_change_component(), l4cpu_reserve_delayed_preempt_component(), l4cpu_reserve_delete_task_component(), l4cpu_reserve_delete_thread_component(), l4cpu_reserve_scheds_get_component(), l4cpu_reserve_time_demand_component(), l4cpu_reserve_watch_component(), monitor_start(), monitor_thread_dl(), and watch_hit_ts().

l4semaphore_t scheds_lock = L4SEMAPHORE_UNLOCKED

Definition at line 22 of file sched.c.

Referenced by lock_scheds(), and unlock_scheds().


Functions
int	sched_init (void)
	initalize arrays
int	sched_index (int prio)
static int	get_max_dp (int prio, sched_t *new_)
	Get max blocking time due to non-preemption for a thread.
int	sched_response_time (sched_t sched, int from, sched_t new_)
	Get the response time of the thread s.
int	sched_free (int pos)
	Free an element at the given position.
int	sched_prepare_free (int pos)
	Ask the watcher of a sched-entry to stop and wait for its readiness.
void	lock_scheds (void)
void	unlock_scheds (void)
Variables
int	sched_cur_threads
int	sched_max_threads
sched_t **	scheds
l4semaphore_t	scheds_lock = L4SEMAPHORE_UNLOCKED