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sys/vtimer: Fix longterm_tick_timer handling.

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Before, the longterm_tick_timer had special handling in update_shortterm.
This approach was bad because the longterm_tick_timer's shooting microseconds time
had different semantics like the rest and thus it could end up in a blocking
position in the priority queue at some point in time, although it should
get executed at another point in time.

Made the longterm_tick_timer handling / meaning of its microseconds the same
as the other timers and also removed seconds, because it is now the same
as longertm_tick_timer.absolute.seconds.

See also https://github.com/RIOT-OS/RIOT/pull/2515
This commit is contained in:
Björn Lichtblau 2015-03-04 13:52:19 +01:00
parent 645ba51eba
commit 2ee6ff0cfd
1 changed files with 8 additions and 18 deletions
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26
sys/vtimer/vtimer.c
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@ -69,8 +69,6 @@ static volatile int in_callback = false;
static int hwtimer_id = -1; static int hwtimer_id = -1;
static uint32_t hwtimer_next_absolute; static uint32_t hwtimer_next_absolute;
static uint32_t seconds = 0;
static inline priority_queue_node_t *timer_get_node(vtimer_t *timer) static inline priority_queue_node_t *timer_get_node(vtimer_t *timer)
{ {
if (!timer) { if (!timer) {
@ -117,19 +115,12 @@ static int update_shortterm(void)
/* short term part of the next vtimer */ /* short term part of the next vtimer */
hwtimer_next_absolute = shortterm_priority_queue_root.first->priority; hwtimer_next_absolute = shortterm_priority_queue_root.first->priority;
uint32_t next = hwtimer_next_absolute; uint32_t next = hwtimer_next_absolute + longterm_tick_start;
/* current short term time */ /* current short term time */
uint32_t now_ticks = hwtimer_now(); uint32_t now_ticks = hwtimer_now();
uint32_t now = HWTIMER_TICKS_TO_US(now_ticks); uint32_t now = HWTIMER_TICKS_TO_US(now_ticks);
/* make sure the longterm_tick_timer does not get truncated */
if (node_get_timer(shortterm_priority_queue_root.first)->action != vtimer_callback_tick) {
/* the next vtimer to schedule is the long term tick */
/* it has a shortterm offset of longterm_tick_start */
next += longterm_tick_start;
}
if((next - HWTIMER_TICKS_TO_US(VTIMER_THRESHOLD) - now) > MICROSECONDS_PER_TICK ) { if((next - HWTIMER_TICKS_TO_US(VTIMER_THRESHOLD) - now) > MICROSECONDS_PER_TICK ) {
DEBUG("truncating next (next - HWTIMER_TICKS_TO_US(VTIMER_THRESHOLD) - now): %lu\n", (next - HWTIMER_TICKS_TO_US(VTIMER_THRESHOLD) - now)); DEBUG("truncating next (next - HWTIMER_TICKS_TO_US(VTIMER_THRESHOLD) - now): %lu\n", (next - HWTIMER_TICKS_TO_US(VTIMER_THRESHOLD) - now));
next = now + HWTIMER_TICKS_TO_US(VTIMER_BACKOFF); next = now + HWTIMER_TICKS_TO_US(VTIMER_BACKOFF);
@ -147,16 +138,16 @@ void vtimer_callback_tick(vtimer_t *timer)
(void) timer; (void) timer;
DEBUG("vtimer_callback_tick().\n"); DEBUG("vtimer_callback_tick().\n");
seconds += SECONDS_PER_TICK;
longterm_tick_start = longterm_tick_timer.absolute.microseconds; longterm_tick_start += MICROSECONDS_PER_TICK;
longterm_tick_timer.absolute.microseconds += MICROSECONDS_PER_TICK; longterm_tick_timer.absolute.seconds += SECONDS_PER_TICK;
longterm_tick_timer.absolute.microseconds = MICROSECONDS_PER_TICK; // Should never change, just for clarity.
set_shortterm(&longterm_tick_timer); set_shortterm(&longterm_tick_timer);
while (longterm_priority_queue_root.first) { while (longterm_priority_queue_root.first) {
vtimer_t *timer = node_get_timer(longterm_priority_queue_root.first); vtimer_t *timer = node_get_timer(longterm_priority_queue_root.first);
if (timer->absolute.seconds == seconds) { if (timer->absolute.seconds == longterm_tick_timer.absolute.seconds) {
priority_queue_remove_head(&longterm_priority_queue_root); priority_queue_remove_head(&longterm_priority_queue_root);
set_shortterm(timer); set_shortterm(timer);
} }
@ -264,7 +255,7 @@ static int vtimer_set(vtimer_t *timer)
} }
unsigned state = disableIRQ(); unsigned state = disableIRQ();
if (timer->absolute.seconds != seconds) { if (timer->absolute.seconds != longterm_tick_timer.absolute.seconds) {
/* we're long-term */ /* we're long-term */
DEBUG("vtimer_set(): setting long_term\n"); DEBUG("vtimer_set(): setting long_term\n");
result = set_longterm(timer); result = set_longterm(timer);
@ -289,9 +280,9 @@ static int vtimer_set(vtimer_t *timer)
void vtimer_now(timex_t *out) void vtimer_now(timex_t *out)
{ {
uint32_t us = HWTIMER_TICKS_TO_US(hwtimer_now()) - longterm_tick_start; uint32_t us = HWTIMER_TICKS_TO_US(hwtimer_now()) - longterm_tick_start;
uint32_t us_per_s = 1000ul * 1000ul; static const uint32_t us_per_s = 1000ul * 1000ul;
out->seconds = seconds + us / us_per_s; out->seconds = longterm_tick_timer.absolute.seconds + us / us_per_s;
out->microseconds = us % us_per_s; out->microseconds = us % us_per_s;
} }
@ -319,7 +310,6 @@ int vtimer_init(void)
{ {
DEBUG("vtimer_init().\n"); DEBUG("vtimer_init().\n");
unsigned state = disableIRQ(); unsigned state = disableIRQ();
seconds = 0;
longterm_tick_start = 0; longterm_tick_start = 0;