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Sporadic scheduler: Move pending time into each timer instance

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This commit is contained in:
Gregory Nutt 2015-07-27 14:48:21 -06:00
parent dce921c1cd
commit e33c727520
2 changed files with 45 additions and 21 deletions
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2
include/nuttx/sched.h
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@ -254,6 +254,7 @@ struct replenishment_s
FAR struct tcb_s *tcb; /* The parent TCB structure */
struct wdog_s timer; /* Timer dedicated to this interval */
uint32_t budget; /* Current budget time */
uint32_t unrealized; /* Unrealized time of budget time */
bool active; /* True: replenishment instance is busy */
};
@ -272,7 +273,6 @@ 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 pending; /* Unrealized, pending execution budget */
#ifdef CONFIG_SCHED_TICKLESS
struct timespec sched_time; /* Time in ticks last processed */

62
sched/sched/sched_sporadic.c
View File

@ -185,6 +185,7 @@ static int sporadic_budget_start(FAR struct tcb_s *tcb,
tcb->timeslice = budget;
sporadic->active = repl;
repl->budget = budget;
repl->unrealized = 0;
#ifdef CONFIG_SCHED_TICKLESS
/* Save the time that the replenishment interval started */
@ -232,8 +233,7 @@ static int sporadic_budget_next(FAR struct replenishment_s *repl)
* budget was used on this timer in the last cycle)
*/
budget = sporadic->pending;
sporadic->pending = 0;
budget = repl->unrealized;
/* If the budget zero, then all of the budget has been utilized. There
* are now two possibilities: (1) There are multiple, active
@ -658,8 +658,7 @@ int sched_sporadic_start(FAR struct tcb_s *tcb)
DEBUGASSERT(sporadic->low_priority <= sporadic->hi_priority);
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);
DEBUGASSERT(sporadic->nrepls == 0 && sporadic->active == NULL);
/* Allocate the first replenishment timer (should never fail) */
@ -668,7 +667,6 @@ int sched_sporadic_start(FAR struct tcb_s *tcb)
/* Then start the first interval */
sporadic->pending = sporadic->budget;
return sporadic_budget_start(tcb, repl, sporadic->budget);
}
@ -758,6 +756,9 @@ int sched_sporadic_reset(FAR struct tcb_s *tcb)
/* Re-initialize replenishment data */
repl->tcb = tcb;
repl->budget = 0;
repl->unrealized = 0;
repl->active = false;
}
/* Reset sporadic scheduling parameters and state data */
@ -768,7 +769,6 @@ int sched_sporadic_reset(FAR struct tcb_s *tcb)
sporadic->nrepls = 0;
sporadic->repl_period = 0;
sporadic->budget = 0;
sporadic->pending = 0;
sporadic->active = NULL;
return OK;
}
@ -803,6 +803,7 @@ int sched_sporadic_resume(FAR struct tcb_s *tcb)
{
FAR struct sporadic_s *sporadic;
FAR struct replenishment_s *repl;
uint32_t budget;
uint32_t last;
DEBUGASSERT(tcb && tcb->sporadic);
@ -825,6 +826,38 @@ int sched_sporadic_resume(FAR struct tcb_s *tcb)
DEBUGASSERT(sporadic->active);
last = sporadic->active->budget;
#ifdef CONFIG_SCHED_TICKLESS
/* Get the difference in time between the time that the scheduler just
* ran and time time that the thread was suspended. This difference,
* then, is the unaccounted for time between the time that the timer
* was started and when the thread was suspended.
*/
clock_timespec_subtract(suspend_time, &sporadic->sched_time,
&elapsed_time);
/* Convert to ticks */
elapsed_ticks = SEC2TICK(elapsed_time.tv_sec);
elapsed_ticks += NSEC2TICK(elapsed_time.tv_nsec);
/* One possibility is that the the elapsed time is greater than the
* time remaining in the time slice. This is a a race condition. It
* means that the timer has just expired. the interrupt will occu
* soon.
*/
if (elapsed_ticks >= tcb->timeslice)
{
return;
}
/* Otherwise, the unrealized time in this budget is the sum time slice
* value minus, the time from the unexpired timer.
*/
tcb->timeslice -= (int32_t)elapsed_ticks;
#endif
/* 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.
@ -873,7 +906,7 @@ int sched_sporadic_resume(FAR struct tcb_s *tcb)
* tickless mode. In this case, there is unaccounted for time from the
* time that the last interval timer was started up until this point.
*
* This function calculates the elpased time since then, and adjusts the
* This function calculates the elapsed time since then, and adjusts the
* timeslice time accordingly.
*
* Input Parameters:
@ -898,8 +931,6 @@ int sched_sporadic_suspend(FAR struct tcb_s *tcb,
struct timespec elapsed_time;
uint32_t elapsed_ticks;
#endif
uint32_t pending = tcb->timeslice;
uint32_t last;
DEBUGASSERT(tcb && tcb->sporadic);
sporadic = tcb->sporadic;
@ -951,18 +982,13 @@ int sched_sporadic_suspend(FAR struct tcb_s *tcb,
return;
}
/* Otherwise, the pending time in this budget is the sum time slice
/* Otherwise, the unrealized time in this budget is the sum time slice
* value minus, the time from the unexpired timer.
*/
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.
@ -970,12 +996,10 @@ int sched_sporadic_suspend(FAR struct tcb_s *tcb,
* not execute.
*/
DEBUGASSERT(last >= tcb->timeslice);
pending = last - tcb->timeslice;
DEBUGASSERT(pending <= sporadic->budget);
DEBUGASSERT(sporadic->active);
sporadic->active->unrealized = tcb->timeslice;
}
sporadic->pending = pending;
return OK;
}