From f39f667a69cf5c4bc0dd4555537615022767f0f9 Mon Sep 17 00:00:00 2001 From: Sebastian Huber Date: Wed, 14 May 2014 13:50:48 +0200 Subject: score: Simplify _Thread_Change_priority() The function to change a thread priority was too complex. Simplify it with a new scheduler operation. This increases the average case performance due to the simplified logic. The interrupt disabled critical section is a bit prolonged since now the extract, update and enqueue steps are executed atomically. This should however not impact the worst-case interrupt latency since at least for the Deterministic Priority Scheduler this sequence can be carried out with a wee bit of instructions and no loops. Add _Scheduler_Change_priority() to replace the sequence of - _Thread_Set_transient(), - _Scheduler_Extract(), - _Scheduler_Enqueue(), and - _Scheduler_Enqueue_first(). Delete STATES_TRANSIENT, _States_Is_transient() and _Thread_Set_transient() since this state is now superfluous. With this change it is possible to get rid of the SCHEDULER_SMP_NODE_IN_THE_AIR state. This considerably simplifies the implementation of the new SMP locking protocols. --- cpukit/score/include/rtems/score/schedulersimple.h | 71 ++-------------------- 1 file changed, 5 insertions(+), 66 deletions(-) (limited to 'cpukit/score/include/rtems/score/schedulersimple.h') diff --git a/cpukit/score/include/rtems/score/schedulersimple.h b/cpukit/score/include/rtems/score/schedulersimple.h index 213bbb2709..6b59a0ab9e 100644 --- a/cpukit/score/include/rtems/score/schedulersimple.h +++ b/cpukit/score/include/rtems/score/schedulersimple.h @@ -42,12 +42,10 @@ extern "C" { _Scheduler_simple_Yield, /* yield entry point */ \ _Scheduler_simple_Block, /* block entry point */ \ _Scheduler_simple_Unblock, /* unblock entry point */ \ + _Scheduler_simple_Change_priority, /* change priority entry point */ \ _Scheduler_default_Allocate, /* allocate entry point */ \ _Scheduler_default_Free, /* free entry point */ \ _Scheduler_default_Update, /* update entry point */ \ - _Scheduler_simple_Enqueue, /* enqueue entry point */ \ - _Scheduler_simple_Enqueue_first, /* enqueue_first entry point */ \ - _Scheduler_simple_Extract, /* extract entry point */ \ _Scheduler_priority_Priority_compare, /* compares two priorities */ \ _Scheduler_default_Release_job, /* new period of task */ \ _Scheduler_default_Tick, /* tick entry point */ \ @@ -136,70 +134,11 @@ void _Scheduler_simple_Unblock( Thread_Control *the_thread ); -/** - * @brief Removes a simple-priority-based thread from a simple queue. - * - * This routine removes a specific thread from the specified - * simple-based ready queue. - * - * @param[in] the_thread is the thread to be blocked - */ -void _Scheduler_simple_Extract( +void _Scheduler_simple_Change_priority( const Scheduler_Control *scheduler, - Thread_Control *the_thread -); - -/** - * @brief Puts simple-priority-based thread onto the ready queue. - * - * This routine puts @a the_thread on to the ready queue. - * - * @param[in] the_thread is the thread to be enqueued - */ -void _Scheduler_simple_Enqueue( - const Scheduler_Control *scheduler, - Thread_Control *the_thread -); - -/** - * @brief Put simple-priority-based @a the_thread to - * the head of the ready queue. - * - * This routine puts @a the_thread to the head of the ready queue. - * The thread will be the first thread at its priority level. - * - * @param[in] the_thread is the thread to be blocked - */ -void _Scheduler_simple_Enqueue_first( - const Scheduler_Control *scheduler, - Thread_Control *the_thread -); - -/** - * _Scheduler_simple_Ready_queue_enqueue - * - * This routine puts @a the_thread on the ready queue - * at the end of its priority group. - * - * @param[in] the_thread - pointer to a thread control block - */ -void _Scheduler_simple_Ready_queue_enqueue( - const Scheduler_Control *scheduler, - Thread_Control *the_thread -); - -/** - * @brief Puts simple-priority-based @a the_thread on to the ready queue - * at the beginning of its priority group. - * - * This routine puts @a the_thread on to the ready queue - * at the beginning of its priority group. - * - * @param[in] the_thread - pointer to a thread control block - */ -void _Scheduler_simple_Ready_queue_enqueue_first( - const Scheduler_Control *scheduler, - Thread_Control *the_thread + Thread_Control *the_thread, + Priority_Control new_priority, + bool prepend_it ); /**@}*/ -- cgit v1.2.3