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Use the last budgeted time from the last timer started

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This commit is contained in:
Gregory Nutt 2015-07-27 13:13:30 -06:00
parent 8c754ccd4f
commit e66e2f5c0f
2 changed files with 55 additions and 34 deletions
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7
include/nuttx/sched.h
View File

@ -272,14 +272,17 @@ struct sporadic_s
uint8_t nrepls; /* Number of active replenishments */
uint32_t repl_period; /* Sporadic replenishment period */
uint32_t budget; /* Sporadic execution budget period */
uint32_t last; /* Last budget time */
uint32_t pending; /* Unrealized, pending execution budget */
#ifdef CONFIG_SCHED_TICKLESS
struct timespec sched_time; /* Time in ticks last processed */
#endif
/* This is the list of replenishment intervals */
/* This is the last interval timer activated */
FAR struct replenishment_s *active;
/* This is the list of replenishment interval timers */
struct replenishment_s replenishments[CONFIG_SCHED_SPORADIC_MAXREPL];
};

82
sched/sched/sched_sporadic.c
View File

@ -176,16 +176,15 @@ static int sporadic_budget_start(FAR struct tcb_s *tcb,
uint32_t budget)
{
FAR struct sporadic_s *sporadic;
int ret;
DEBUGASSERT(tcb && tcb->sporadic);
sporadic = tcb->sporadic;
/* Start the next replenishment interval */
tcb->timeslice = budget;
sporadic->last = budget;
repl->budget = budget;
tcb->timeslice = budget;
sporadic->active = repl;
repl->budget = budget;
#ifdef CONFIG_SCHED_TICKLESS
/* Save the time that the replenishment interval started */
@ -229,13 +228,15 @@ static int sporadic_budget_next(FAR struct replenishment_s *repl)
sporadic = tcb->sporadic;
DEBUGASSERT(sporadic != NULL);
/* The budgeted interval will be the pending budget */
/* The budgeted interval will be the unrealized budget (unless the full
* budget was used on this timer in the last cycle)
*/
budget = sporadic->pending;
sporadic->pending = 0;
/* If the budget zero, then all of the pending budget has been utilized.
* There are now two possibilities: (1) There are multiple, active
/* If the budget zero, then all of the budget has been utilized. There
* are now two possibilities: (1) There are multiple, active
* replenishment threads so this one is no longer needed, or (2) there is
* only one and we need to restart the budget interval with the full
* budget.
@ -253,7 +254,6 @@ static int sporadic_budget_next(FAR struct replenishment_s *repl)
sporadic->nrepls--;
return sporadic_set_hipriority(tcb);
return OK;
}
else
{
@ -659,6 +659,7 @@ int sched_sporadic_start(FAR struct tcb_s *tcb)
DEBUGASSERT(sporadic->max_repl <= CONFIG_SCHED_SPORADIC_MAXREPL);
DEBUGASSERT(sporadic->budget > 0 && sporadic->budget <= sporadic->repl_period);
DEBUGASSERT(sporadic->nrepls == 0 && sporadic->pending == 0);
DEBUGASSERT(sporadic->active == NULL);
/* Allocate the first replenishment timer (should never fail) */
@ -768,6 +769,7 @@ int sched_sporadic_reset(FAR struct tcb_s *tcb)
sporadic->repl_period = 0;
sporadic->budget = 0;
sporadic->pending = 0;
sporadic->active = NULL;
return OK;
}
@ -801,6 +803,7 @@ int sched_sporadic_resume(FAR struct tcb_s *tcb)
{
FAR struct sporadic_s *sporadic;
FAR struct replenishment_s *repl;
uint32_t last;
DEBUGASSERT(tcb && tcb->sporadic);
sporadic = tcb->sporadic;
@ -813,35 +816,44 @@ int sched_sporadic_resume(FAR struct tcb_s *tcb)
/* Check if are in the budget portion of the replenishment interval. We
* know this is the case if the current timeslice is non-zero.
*
* This function could also be called before the budget period has had a
* chance to run, i.e., when the value of timeslice has not been decremented
* and is still equal to the initial value.
*
* This latter case could occur if the thread has never had a chance to
* run and is also very likely when the thread is just restarted after
* raising its priority at the beginning of the budget period. We would
* not want to start a new timer in these cases.
*/
if (tcb->timeslice > 0 && tcb->timeslice < sporadic->last)
if (tcb->timeslice > 0)
{
/* Allocate a new replenishment timer. This will limit us to
* to maximum number of replenishments (max_repl).
/* Get the last budgeted time */
DEBUGASSERT(sporadic->active);
last = sporadic->active->budget;
/* This function could also be called before the budget period has had
* a chance to run, i.e., when the value of timeslice has not been
* decremented and is still equal to the initial value.
*
* This latter case could occur if the thread has never had a chance
* to run and is also very likely when the thread is just restarted
* after raising its priority at the beginning of the budget period.
* We would not want to start a new timer in these cases.
*/
repl = sporadic_alloc_repl(sporadic);
if (repl != NULL)
if (tcb->timeslice < last)
{
return sporadic_budget_start(tcb, repl, tcb->timeslice);
/* Allocate a new replenishment timer. This will limit us to
* to maximum number of replenishments (max_repl).
*/
repl = sporadic_alloc_repl(sporadic);
if (repl != NULL)
{
return sporadic_budget_start(tcb, repl, tcb->timeslice);
}
/* We need to return success even on a failure to allocate. Doing
* nothing is our fall-back behavior and that is not a failure from
* the standpoint of higher level logic.
*/
slldbg("Failed to allocate timer, nrepls=%d\n", sporadic->nrepls);
}
/* We need to return success even on a failure to allocate. Doing
* nothing is our fall-back behavior and that is not a failure from
* the standpoint of higher level logic.
*/
slldbg("Failed to allocate timer, nrepls=%d\n", sporadic->nrepls);
}
#ifdef CONFIG_SCHED_TICKLESS
@ -887,6 +899,7 @@ int sched_sporadic_suspend(FAR struct tcb_s *tcb,
uint32_t elapsed_ticks;
#endif
uint32_t pending = tcb->timeslice;
uint32_t last;
DEBUGASSERT(tcb && tcb->sporadic);
sporadic = tcb->sporadic;
@ -945,6 +958,11 @@ int sched_sporadic_suspend(FAR struct tcb_s *tcb,
tcb->timeslice -= (int32_t)elapsed_ticks;
#endif
/* Get the last budgeted time */
DEBUGASSERT(sporadic->active);
last = sporadic->active->budget;
/* Handle any part of the budget that was not utilized.
*
* current = The initial budget at the beginning of the interval.
@ -952,8 +970,8 @@ int sched_sporadic_suspend(FAR struct tcb_s *tcb,
* not execute.
*/
DEBUGASSERT(sporadic->last >= tcb->timeslice);
pending = sporadic->last - tcb->timeslice;
DEBUGASSERT(last >= tcb->timeslice);
pending = last - tcb->timeslice;
DEBUGASSERT(pending <= sporadic->budget);
}