sched/semaphore: add sem_count temporary variable to improve performance
@@ -71,6 +71,7 @@ int nxsem_post(FAR sem_t *sem)
{
FAR struct tcb_s *stcb = NULL;
irqstate_t flags;
+ int16_t sem_count;
int ret = -EINVAL;
/* Make sure we were supplied with a valid semaphore. */
@@ -84,9 +85,11 @@ int nxsem_post(FAR sem_t *sem)
flags = enter_critical_section();
+ sem_count = sem->semcount;
+
/* Check the maximum allowable value */
- if (sem->semcount >= SEM_VALUE_MAX)
+ if (sem_count >= SEM_VALUE_MAX)
{
leave_critical_section(flags);
return -EOVERFLOW;
@@ -110,7 +113,8 @@ int nxsem_post(FAR sem_t *sem)
*/
nxsem_release_holder(sem);
- sem->semcount++;
+ sem_count++;
+ sem->semcount = sem_count;
#ifdef CONFIG_PRIORITY_INHERITANCE
/* Don't let any unblocked tasks run until we complete any priority
@@ -127,7 +131,7 @@ int nxsem_post(FAR sem_t *sem)
* there must be some task waiting for the semaphore.
*/
- if (sem->semcount <= 0)
+ if (sem_count <= 0)
{
/* Check if there are any tasks in the waiting for semaphore
* task list that are waiting for this semaphore. This is a
