Skip to content

sys: xtimer: WIP: xtimer refactoring #5355

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
malosek wants to merge 1 commit into from
Closed

sys: xtimer: WIP: xtimer refactoring #5355

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 1 addition & 2 deletions sys/include/xtimer.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -169,7 +169,7 @@ static inline void xtimer_spin(uint32_t microseconds);
* @param[in] usecs time in microseconds that will be added to
* last_wakeup
*/
void xtimer_usleep_until(uint32_t *last_wakeup, uint32_t usecs);
void xtimer_usleep_until(uint64_t *last_wakeup, uint32_t usecs);

/**
* @brief Set a timer that sends a message
Expand Down Expand Up @@ -426,7 +426,6 @@ static inline uint32_t _lltimer_mask(uint32_t val)
* @brief xtimer internal stuff
* @internal
*/
int _xtimer_set_absolute(xtimer_t *timer, uint32_t target);
void _xtimer_set64(xtimer_t *timer, uint32_t offset, uint32_t long_offset);
void _xtimer_sleep(uint32_t offset, uint32_t long_offset);
static inline void xtimer_spin_until(uint32_t value);
Expand Down
54 changes: 8 additions & 46 deletions sys/xtimer/xtimer.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -46,60 +46,22 @@ void _xtimer_sleep(uint32_t offset, uint32_t long_offset)

timer.callback = _callback_unlock_mutex;
timer.arg = (void*) &mutex;
timer.target = timer.long_target = 0;

mutex_lock(&mutex);
_xtimer_set64(&timer, offset, long_offset);
mutex_lock(&mutex);
}

void xtimer_usleep_until(uint32_t *last_wakeup, uint32_t interval) {
xtimer_t timer;
mutex_t mutex = MUTEX_INIT;

timer.callback = _callback_unlock_mutex;
timer.arg = (void*) &mutex;

uint32_t target = *last_wakeup + interval;

uint32_t now = xtimer_now();
/* make sure we're not setting a value in the past */
if (now < *last_wakeup) {
/* base timer overflowed */
if (!((target < *last_wakeup) && (target > now))) {
goto out;
}
}
else if (! ((target < *last_wakeup) || (target > now))) {
goto out;
}
void xtimer_usleep_until(uint64_t *last_wakeup, uint32_t interval)
{
// Calculate absolute target time.
uint64_t target = *last_wakeup + interval;
// Calculate compensated offset.
uint64_t now = xtimer_now64();
uint64_t offset = target - now;

/* For large offsets, set an absolute target time, as
* it is more exact.
*
* As that might cause an underflow, for small offsets,
* use a relative offset, as that can never underflow.
*
* For very small offsets, spin.
*/
uint32_t offset = target - now;

if (offset > (XTIMER_BACKOFF * 2)) {
mutex_lock(&mutex);
if (offset >> 9) { /* >= 512 */
offset = target;
}
else {
offset += xtimer_now();
}
_xtimer_set_absolute(&timer, offset);
mutex_lock(&mutex);
}
else {
xtimer_spin(offset);
}
_xtimer_sleep(offset, offset >> 32);

out:
*last_wakeup = target;
}

Expand Down
123 changes: 42 additions & 81 deletions sys/xtimer/xtimer_core.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -90,48 +90,60 @@ uint64_t xtimer_now64(void)
void _xtimer_set64(xtimer_t *timer, uint32_t offset, uint32_t long_offset)
{
DEBUG(" _xtimer_set64() offset=%" PRIu32 " long_offset=%" PRIu32 "\n", offset, long_offset);
if (!long_offset) {
/* timer fits into the short timer */
xtimer_set(timer, (uint32_t) offset);
}
else {
int state = irq_disable();
if (_is_set(timer)) {
_remove(timer);
}

_xtimer_now64(&timer->target, &timer->long_target);
timer->target += offset;
timer->long_target += long_offset;
if (timer->target < offset) {
timer->long_target++;
}

_add_timer_to_long_list(&long_list_head, timer);
irq_restore(state);
DEBUG("xtimer_set64(): added longterm timer (long_target=%" PRIu32 " target=%" PRIu32 ")\n",
timer->long_target, timer->target);
}
}

void xtimer_set(xtimer_t *timer, uint32_t offset)
{
DEBUG("timer_set(): offset=%" PRIu32 " now=%" PRIu32 " (%" PRIu32 ")\n", offset, xtimer_now(), _lltimer_now());
if (!timer->callback) {
DEBUG("timer_set(): timer has no callback.\n");
DEBUG("_xtimer_set64(): timer has no callback.\n");
return;
}

xtimer_remove(timer);

if (offset < XTIMER_BACKOFF) {
if (!long_offset && offset < XTIMER_BACKOFF) {
xtimer_spin(offset);
_shoot(timer);
}

unsigned state = irq_disable();

// Take timer snapshot.
uint32_t now_short_term, now_long_term;
_xtimer_now64 (&now_short_term, &now_long_term);

// Calculate absolute target.
timer->target = now_short_term + offset;
timer->long_target = now_long_term + long_offset;
if (timer->target < offset)
{
timer->long_target++;
}

if ( (timer->long_target != _long_cnt) || !_this_high_period(timer->target) ) {
DEBUG("_xtimer_set64(): the timer doesn't fit into the low-level timer's mask.\n");
_add_timer_to_long_list(&long_list_head, timer);
}
else {
uint32_t target = xtimer_now() + offset;
_xtimer_set_absolute(timer, target);
if (_lltimer_mask(now_short_term) >= timer->target) {
DEBUG("_xtimer_set64(): the timer will expire in the next timer period\n");
_add_timer_to_list(&overflow_list_head, timer);
}
else {
DEBUG("_xtimer_set64(): timer will expire in this timer period.\n");
_add_timer_to_list(&timer_list_head, timer);

if (timer_list_head == timer) {
DEBUG("_xtimer_set64(): timer is new list head. updating lltimer.\n");
_lltimer_set(timer->target - XTIMER_OVERHEAD);
}
}
}

irq_restore(state);
}

void xtimer_set(xtimer_t *timer, uint32_t offset)
{
DEBUG("timer_set(): offset=%" PRIu32 " now=%" PRIu32 " (%" PRIu32 ")\n", offset, xtimer_now(), _lltimer_now());
_xtimer_set64(timer, offset, 0);
}

static void _periph_timer_callback(void *arg, int chan)
Expand Down Expand Up @@ -161,57 +173,6 @@ static inline void _lltimer_set(uint32_t target)
timer_set_absolute(XTIMER, XTIMER_CHAN, _lltimer_mask(target));
}

int _xtimer_set_absolute(xtimer_t *timer, uint32_t target)
{
uint32_t now = xtimer_now();
int res = 0;

DEBUG("timer_set_absolute(): now=%" PRIu32 " target=%" PRIu32 "\n", now, target);

timer->next = NULL;
if ((target >= now) && ((target - XTIMER_BACKOFF) < now)) {
/* backoff */
xtimer_spin_until(target + XTIMER_BACKOFF);
_shoot(timer);
return 0;
}

unsigned state = irq_disable();
if (_is_set(timer)) {
_remove(timer);
}

timer->target = target;
timer->long_target = _long_cnt;
if (target < now) {
timer->long_target++;
}

if ( (timer->long_target > _long_cnt) || !_this_high_period(target) ) {
DEBUG("xtimer_set_absolute(): the timer doesn't fit into the low-level timer's mask.\n");
_add_timer_to_long_list(&long_list_head, timer);
}
else {
if (_lltimer_mask(now) >= target) {
DEBUG("xtimer_set_absolute(): the timer will expire in the next timer period\n");
_add_timer_to_list(&overflow_list_head, timer);
}
else {
DEBUG("timer_set_absolute(): timer will expire in this timer period.\n");
_add_timer_to_list(&timer_list_head, timer);

if (timer_list_head == timer) {
DEBUG("timer_set_absolute(): timer is new list head. updating lltimer.\n");
_lltimer_set(target - XTIMER_OVERHEAD);
}
}
}

irq_restore(state);

return res;
}

static void _add_timer_to_list(xtimer_t **list_head, xtimer_t *timer)
{
while (*list_head && (*list_head)->target <= timer->target) {
Expand Down