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sys/event: add event loop debug threshold #21763

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964357a
sys/event: add event loop debug threshold
kfessel Oct 6, 2025
d888d46
sys/event: clang-format
kfessel Oct 6, 2025
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58 changes: 42 additions & 16 deletions sys/include/event.h
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Original file line number Diff line number Diff line change
Expand Up @@ -116,18 +116,24 @@ extern "C" {
/**
* @brief Thread flag use to notify available events in an event queue
*/
#define THREAD_FLAG_EVENT (0x1)
# define THREAD_FLAG_EVENT (0x1)
#endif

/**
* @brief event_queue_t static initializer
*/
#define EVENT_QUEUE_INIT { .waiter = thread_get_active() }
#define EVENT_QUEUE_INIT \
{ \
.waiter = thread_get_active() \
}

/**
* @brief static initializer for detached event queues
*/
#define EVENT_QUEUE_INIT_DETACHED { .waiter = NULL }
#define EVENT_QUEUE_INIT_DETACHED \
{ \
.waiter = NULL \
}

/**
* @brief event structure forward declaration
Expand All @@ -143,16 +149,16 @@ typedef void (*event_handler_t)(event_t *);
* @brief event structure
*/
struct event {
clist_node_t list_node; /**< event queue list entry */
event_handler_t handler; /**< pointer to event handler function */
clist_node_t list_node; /**< event queue list entry */
event_handler_t handler; /**< pointer to event handler function */
};

/**
* @brief event queue structure
*/
typedef struct PTRTAG {
clist_node_t event_list; /**< list of queued events */
thread_t *waiter; /**< thread owning event queue */
clist_node_t event_list; /**< list of queued events */
thread_t *waiter; /**< thread owning event queue */
} event_queue_t;

/**
Expand All @@ -164,7 +170,7 @@ typedef struct PTRTAG {
* @param[in] n_queues number of queues in @p queues
*/
static inline void event_queues_init(event_queue_t *queues,
size_t n_queues)
size_t n_queues)
{
assert(queues && n_queues);
thread_t *me = thread_get_active();
Expand Down Expand Up @@ -193,7 +199,7 @@ static inline void event_queue_init(event_queue_t *queue)
* @param[in] n_queues number of queues in @p queues
*/
static inline void event_queues_init_detached(event_queue_t *queues,
size_t n_queues)
size_t n_queues)
{
assert(queues);
for (size_t i = 0; i < n_queues; i++) {
Expand Down Expand Up @@ -405,6 +411,19 @@ event_t *event_wait_timeout_ztimer(event_queue_t *queue,
ztimer_clock_t *clock, uint32_t timeout);
#endif

/**
* @brief Threshold in microseconds below which event_handler
* are not printed while debugging.
*
* This can be used for debugging event loops. Setting a value
* other than zero will also remove the event_handler start message.
*
* Use this to prevent *a lot* of output when debugging.
*/
#ifndef CONFIG_EVENT_LOOP_DEBUG_THRESHOLD_US
# define CONFIG_EVENT_LOOP_DEBUG_THRESHOLD_US (0)
#endif

/**
* @brief Simple event loop with multiple queues
*
Expand Down Expand Up @@ -438,21 +457,28 @@ static inline void event_loop_multi(event_queue_t *queues, size_t n_queues)
while (1) {
event_t *event = event_wait_multi(queues, n_queues);
if (IS_USED(MODULE_EVENT_LOOP_DEBUG)) {
uint32_t now;
ztimer_acquire(ZTIMER_USEC);

void _event_callback_handler(event_t *event);
if (!IS_USED(MODULE_EVENT_CALLBACK) ||
event->handler != _event_callback_handler) {
void _event_callback_handler(event_t * event);
if ((CONFIG_EVENT_LOOP_DEBUG_THRESHOLD_US == 0) &&
(!IS_USED(MODULE_EVENT_CALLBACK) ||
event->handler != _event_callback_handler)) {
printf("event: executing %p->%p\n",
(void *)event, (void *)(uintptr_t)event->handler);
}
now = ztimer_now(ZTIMER_USEC);
uint32_t now = ztimer_now(ZTIMER_USEC);
/* events might modify themself */
void *handler_ptr = (void *)(uintptr_t)event->handler;

event->handler(event);

printf("event: %p took %" PRIu32 " µs\n",
(void *)event, ztimer_now(ZTIMER_USEC) - now);
uint32_t dt = ztimer_now(ZTIMER_USEC) - now;

if ((CONFIG_EVENT_LOOP_DEBUG_THRESHOLD_US == 0) ||
dt > CONFIG_EVENT_LOOP_DEBUG_THRESHOLD_US) {
printf("event: %p->%p ran: %" PRIu32 " usec\n",
(void *)event, handler_ptr, dt);
}
ztimer_release(ZTIMER_USEC);
}
else {
Expand Down