tracing: do not mark thread as switched_out in case of no reschedule

If z_get_next_switch_handle determines no reschdule is needed, do not
mark thread as switched_out in set_curent() where new and old thread are
the same.

See #88596 for more details.

Signed-off-by: Anas Nashif <[email protected]>

Author: nashif

kernel/sched.c

@@ -820,7 +820,12 @@ struct k_thread *z_swap_next_thread(void)
 /* Just a wrapper around z_current_thread_set(xxx) with tracing */
 static inline void set_current(struct k_thread *new_thread)
 {
-	z_thread_mark_switched_out();
+	/* If the new thread is the same as the current thread, we
+	 * don't need to do anything.
+	 */
+	if (IS_ENABLED(CONFIG_INSTRUMENT_THREAD_SWITCHING) && new_thread != _current) {
+		z_thread_mark_switched_out();
+	}
 	z_current_thread_set(new_thread);
 }