kernel: Improve cooperative and preemptive performance as per thread_metric benchmark

include/zephyr/kernel_structs.h

@@ -122,6 +122,9 @@ struct _priq_rb {
 struct _priq_mq {
 	sys_dlist_t queues[K_NUM_THREAD_PRIO];
 	unsigned long bitmask[PRIQ_BITMAP_SIZE];
+#ifndef CONFIG_SMP
+	unsigned int cached_queue_index;
+#endif
 };
 
 struct _ready_q {

include/zephyr/sys/dlist.h

@@ -492,6 +492,29 @@ static inline void sys_dlist_insert_at(sys_dlist_t *list, sys_dnode_t *node,
 	}
 }
 
+/**
+ * @brief remove a specific node from a list
+ *
+ * Like :c:func:`sys_dlist_remove()`, this routine removes a specific node
+ * from a list. However, unlike :c:func:`sys_dlist_remove()`, this routine
+ * does not re-initialize the removed node. One significant implication of
+ * this difference is that the function :c:func`sys_dnode_is_linked()` will
+ * not work on a dequeued node.
+ *
+ * The list is implicit from the node. The node must be part of a list.
+ * This and other sys_dlist_*() functions are not thread safe.
+ *
+ * @param node the node to dequeue
+ */
+static inline void sys_dlist_dequeue(sys_dnode_t *node)
+{
+	sys_dnode_t *const prev = node->prev;
+	sys_dnode_t *const next = node->next;
+
+	prev->next = next;
+	next->prev = prev;
+}
+
 /**
  * @brief remove a specific node from a list
  *

kernel/include/ksched.h

@@ -119,8 +119,6 @@ static inline bool z_is_prio_lower_or_equal(int prio1, int prio2)
 	return z_is_prio1_lower_than_or_equal_to_prio2(prio1, prio2);
 }
 
-int32_t z_sched_prio_cmp(struct k_thread *thread_1, struct k_thread *thread_2);
-
 static inline bool _is_valid_prio(int prio, void *entry_point)
 {
 	if ((prio == K_IDLE_PRIO) && z_is_idle_thread_entry(entry_point)) {

kernel/include/kthread.h

@@ -128,6 +128,16 @@ static inline bool z_is_thread_queued(struct k_thread *thread)
 	return z_is_thread_state_set(thread, _THREAD_QUEUED);
 }
 
+static inline void z_mark_thread_as_queued(struct k_thread *thread)
+{
+	thread->base.thread_state |= _THREAD_QUEUED;
+}
+
+static inline void z_mark_thread_as_not_queued(struct k_thread *thread)
+{
+	thread->base.thread_state &= ~_THREAD_QUEUED;
+}
+
 static inline void z_mark_thread_as_suspended(struct k_thread *thread)
 {
 	thread->base.thread_state |= _THREAD_SUSPENDED;