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canard: added buckets for the RX handler list #81

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Merged
tridge merged 1 commit into from
Jul 12, 2025
Merged

canard: added buckets for the RX handler list #81

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23 changes: 15 additions & 8 deletions canard/handler_list.h
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,13 @@
#define CANARD_NUM_HANDLERS 3
#endif

/*
the number of buckets helps reduce CPU usage when there are many handlers
*/
#ifndef CANARD_NUM_RX_BUCKETS
#define CANARD_NUM_RX_BUCKETS 8U
#endif

namespace Canard {

/// @brief HandlerList to register all handled message types.
Expand Down Expand Up @@ -62,7 +69,7 @@ class HandlerList {
#ifdef WITH_SEMAPHORE
WITH_SEMAPHORE(sem[index]);
#endif
HandlerList* entry = head[index];
HandlerList* entry = head[index][msgid % CANARD_NUM_RX_BUCKETS];
while (entry != nullptr) {
if (entry->msgid == msgid && entry->transfer_type == transfer_type) {
signature = entry->signature;
Expand All @@ -81,7 +88,7 @@ class HandlerList {
#ifdef WITH_SEMAPHORE
WITH_SEMAPHORE(sem[index]);
#endif
HandlerList* entry = head[index];
HandlerList* entry = head[index][transfer.data_type_id % CANARD_NUM_RX_BUCKETS];
while (entry != nullptr) {
if (transfer.data_type_id == entry->msgid &&
entry->transfer_type == transfer.transfer_type) {
Expand Down Expand Up @@ -113,18 +120,18 @@ class HandlerList {
#ifdef WITH_SEMAPHORE
WITH_SEMAPHORE(sem[index]);
#endif
next = head[index];
head[index] = this;
next = head[index][msgid % CANARD_NUM_RX_BUCKETS];
head[index][msgid % CANARD_NUM_RX_BUCKETS] = this;
}

// remove ourselves from the handler list
void unlink(void) NOINLINE_FUNC {
#ifdef WITH_SEMAPHORE
WITH_SEMAPHORE(sem[index]);
#endif
HandlerList* entry = head[index];
HandlerList* entry = head[index][msgid % CANARD_NUM_RX_BUCKETS];
if (entry == this) {
head[index] = next;
head[index][msgid % CANARD_NUM_RX_BUCKETS] = next;
return;
}
while (entry != nullptr) {
Expand All @@ -137,13 +144,13 @@ class HandlerList {
}

private:
static HandlerList* head[CANARD_NUM_HANDLERS];
static HandlerList* head[CANARD_NUM_HANDLERS][CANARD_NUM_RX_BUCKETS];
uint16_t msgid;
uint64_t signature;
CanardTransferType transfer_type;
};

} // namespace Canard

#define DEFINE_HANDLER_LIST_HEADS() Canard::HandlerList* Canard::HandlerList::head[CANARD_NUM_HANDLERS] = {}
#define DEFINE_HANDLER_LIST_HEADS() Canard::HandlerList* Canard::HandlerList::head[CANARD_NUM_HANDLERS][CANARD_NUM_RX_BUCKETS] = {}
#define DEFINE_HANDLER_LIST_SEMAPHORES() Canard::Semaphore Canard::HandlerList::sem[CANARD_NUM_HANDLERS] = {}