Commit cc415bc1 authored by Peter Mitsis's avatar Peter Mitsis Committed by Anas Nashif
Browse files

kernel: Apply 'unlikely' attribute 



Applies the 'unlikely' attribute to various kernel objects that
use z_unpend_first_thread() to optimize for the non-blocking path.

This boosts the thread_metric synchronization benchmark numbers
on the frdm_k64f board by about 10%.

Signed-off-by: default avatarPeter Mitsis <peter.mitsis@intel.com>
parent 89b73368

kernel/condvar.c

+1 −1
Original line number Diff line number Diff line
@@ -49,7 +49,7 @@ int z_impl_k_condvar_signal(struct k_condvar *condvar) 


	struct k_thread *thread = z_unpend_first_thread(&condvar->wait_q);



	if (thread != NULL) {

	if (unlikely(thread != NULL)) {

		SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_condvar, signal, condvar, K_FOREVER);



		arch_thread_return_value_set(thread, 0);

kernel/mem_slab.c

+1 −1
Original line number Diff line number Diff line
@@ -275,7 +275,7 @@ void k_mem_slab_free(struct k_mem_slab *slab, void *mem) 
	if ((slab->free_list == NULL) && IS_ENABLED(CONFIG_MULTITHREADING)) {

		struct k_thread *pending_thread = z_unpend_first_thread(&slab->wait_q);



		if (pending_thread != NULL) {

		if (unlikely(pending_thread != NULL)) {

			SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mem_slab, free, slab);



			z_thread_return_value_set_with_data(pending_thread, 0, mem);

kernel/msg_q.c

+2 −2
Original line number Diff line number Diff line
@@ -136,7 +136,7 @@ int z_impl_k_msgq_put(struct k_msgq *msgq, const void *data, k_timeout_t timeout 
	if (msgq->used_msgs < msgq->max_msgs) {

		/* message queue isn't full */

		pending_thread = z_unpend_first_thread(&msgq->wait_q);

		if (pending_thread != NULL) {

		if (unlikely(pending_thread != NULL)) {

			SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, put, msgq, timeout, 0);



			/* give message to waiting thread */
@@ -236,7 +236,7 @@ int z_impl_k_msgq_get(struct k_msgq *msgq, void *data, k_timeout_t timeout) 


		/* handle first thread waiting to write (if any) */

		pending_thread = z_unpend_first_thread(&msgq->wait_q);

		if (pending_thread != NULL) {

		if (unlikely(pending_thread != NULL)) {

			SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_msgq, get, msgq, timeout);



			/* add thread's message to queue */

kernel/mutex.c

+1 −1
Original line number Diff line number Diff line
@@ -261,7 +261,7 @@ int z_impl_k_mutex_unlock(struct k_mutex *mutex) 
	LOG_DBG("new owner of mutex %p: %p (prio: %d)",

		mutex, new_owner, new_owner ? new_owner->base.prio : -1000);



	if (new_owner != NULL) {

	if (unlikely(new_owner != NULL)) {

		/*

		 * new owner is already of higher or equal prio than first

		 * waiter since the wait queue is priority-based: no need to

kernel/queue.c

+1 −1
Original line number Diff line number Diff line
@@ -133,7 +133,7 @@ static int32_t queue_insert(struct k_queue *queue, void *prev, void *data, 
	}

	first_pending_thread = z_unpend_first_thread(&queue->wait_q);



	if (first_pending_thread != NULL) {

	if (unlikely(first_pending_thread != NULL)) {

		SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_queue, queue_insert, queue, alloc, K_FOREVER);



		prepare_thread_to_run(first_pending_thread, data);

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