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. --- .../include/rtems/score/schedulersimpleimpl.h | 28 ++++++++-------------- 1 file changed, 10 insertions(+), 18 deletions(-) (limited to 'cpukit/score/include/rtems/score/schedulersimpleimpl.h') diff --git a/cpukit/score/include/rtems/score/schedulersimpleimpl.h b/cpukit/score/include/rtems/score/schedulersimpleimpl.h index c256071a8f..b73a1b2c78 100644 --- a/cpukit/score/include/rtems/score/schedulersimpleimpl.h +++ b/cpukit/score/include/rtems/score/schedulersimpleimpl.h @@ -38,24 +38,6 @@ RTEMS_INLINE_ROUTINE Scheduler_simple_Context * return (Scheduler_simple_Context *) _Scheduler_Get_context( scheduler ); } -/** - * This routine puts @a the_thread on to the ready queue. - * - * @param[in] the_ready_queue is a pointer to the ready queue head - * @param[in] the_thread is the thread to be blocked - */ -RTEMS_INLINE_ROUTINE void _Scheduler_simple_Ready_queue_requeue( - const Scheduler_Control *scheduler, - Thread_Control *the_thread -) -{ - /* extract */ - _Chain_Extract_unprotected( &the_thread->Object.Node ); - - /* enqueue */ - _Scheduler_simple_Ready_queue_enqueue( scheduler, the_thread ); -} - RTEMS_INLINE_ROUTINE bool _Scheduler_simple_Insert_priority_lifo_order( const Chain_Node *to_insert, const Chain_Node *next @@ -102,6 +84,16 @@ RTEMS_INLINE_ROUTINE void _Scheduler_simple_Insert_priority_fifo( ); } +RTEMS_INLINE_ROUTINE void _Scheduler_simple_Extract( + const Scheduler_Control *scheduler, + Thread_Control *the_thread +) +{ + (void) scheduler; + + _Chain_Extract_unprotected( &the_thread->Object.Node ); +} + RTEMS_INLINE_ROUTINE void _Scheduler_simple_Schedule_body( const Scheduler_Control *scheduler, Thread_Control *the_thread, -- cgit v1.2.3