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Bluetooth: controller: Be fair when pre-empting a ticker

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When force scheduling a ticker use the number of times the
tickers have already skipped their intervals to decide if
the forced ticker can pre-empt the colliding ticker. This
introduces a fairness amongst tickers contesting for the
overlapping time slice.

Flashing in co-operation with Radio needs to be fair in
order to avoid connection supervision timeouts.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>
This commit is contained in:
Vinayak Kariappa Chettimada 2017-06-25 05:10:48 +02:00 • committed by Carles Cufi
commit 4ba2bb0d1c
1 changed files with 23 additions and 2 deletions
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25
subsys/bluetooth/controller/ticker/ticker.c
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@ -776,20 +776,41 @@ static inline u32_t ticker_job_insert(struct ticker_instance *instance,
{ {
struct ticker_node *node = &instance->node[0]; struct ticker_node *node = &instance->node[0];
u8_t id_collide; u8_t id_collide;
u16_t skip;
/* Prepare to insert */ /* Prepare to insert */
ticker->next = TICKER_NULL; ticker->next = TICKER_NULL;
/* No. of times ticker has skipped its interval */
if (ticker->lazy_current > ticker->lazy_periodic) {
skip = ticker->lazy_current -
ticker->lazy_periodic;
} else {
skip = 0;
}
/* If insert collides, remove colliding or advance to next interval */ /* If insert collides, remove colliding or advance to next interval */
while (id_insert != while (id_insert !=
(id_collide = ticker_enqueue(instance, id_insert))) { (id_collide = ticker_enqueue(instance, id_insert))) {
/* check for collision */ /* check for collision */
if (id_collide != TICKER_NULL) { if (id_collide != TICKER_NULL) {
struct ticker_node *ticker_collide; struct ticker_node *ticker_collide = &node[id_collide];
u16_t skip_collide;
/* No. of times ticker colliding has skipped its
* interval.
*/
if (ticker_collide->lazy_current >
ticker_collide->lazy_periodic) {
skip_collide = ticker_collide->lazy_current -
ticker_collide->lazy_periodic;
} else {
skip_collide = 0;
}
ticker_collide = &node[id_collide];
if (ticker_collide->ticks_periodic && if (ticker_collide->ticks_periodic &&
ticker_collide->ticks_periodic && ticker_collide->ticks_periodic &&
skip_collide <= skip &&
ticker_collide->force < ticker->force) { ticker_collide->force < ticker->force) {
/* dequeue and get the reminder of ticks /* dequeue and get the reminder of ticks
* to expire. * to expire.