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kernel: Minor k_sem_give() performance enhancement

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When a semaphore is given and there is no thread waiting
for it, do not unconditionally perform a reschedule.

Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
This commit is contained in:
Peter Mitsis 2023-04-26 16:27:44 -04:00 committed by Carles Cufí
parent 8c913f8d2d
commit f444fcafdb
1 changed files with 10 additions and 3 deletions
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13
kernel/sem.c
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@ -74,12 +74,14 @@ int z_vrfy_k_sem_init(struct k_sem *sem, unsigned int initial_count,
#include <syscalls/k_sem_init_mrsh.c>
#endif
static inline void handle_poll_events(struct k_sem *sem)
static inline bool handle_poll_events(struct k_sem *sem)
{
#ifdef CONFIG_POLL
z_handle_obj_poll_events(&sem->poll_events, K_POLL_STATE_SEM_AVAILABLE);
return true;
#else
ARG_UNUSED(sem);
return false;
#endif
}
@ -87,6 +89,7 @@ void z_impl_k_sem_give(struct k_sem *sem)
{
k_spinlock_key_t key = k_spin_lock(&lock);
struct k_thread *thread;
bool resched = true;
SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_sem, give, sem);
@ -97,10 +100,14 @@ void z_impl_k_sem_give(struct k_sem *sem)
z_ready_thread(thread);
} else {
sem->count += (sem->count != sem->limit) ? 1U : 0U;
handle_poll_events(sem);
resched = handle_poll_events(sem);
}
z_reschedule(&lock, key);
if (resched) {
z_reschedule(&lock, key);
} else {
k_spin_unlock(&lock, key);
}
SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_sem, give, sem);
}