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/scheduler.h | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) (limited to 'cpukit/score/include/rtems/score/scheduler.h') diff --git a/cpukit/score/include/rtems/score/scheduler.h b/cpukit/score/include/rtems/score/scheduler.h index 7f0b43ae52..b1e8f8ac4f 100644 --- a/cpukit/score/include/rtems/score/scheduler.h +++ b/cpukit/score/include/rtems/score/scheduler.h @@ -63,6 +63,14 @@ typedef struct { /** @see _Scheduler_Unblock() */ void ( *unblock )( const Scheduler_Control *, Thread_Control * ); + /** @see _Scheduler_Change_priority() */ + void ( *change_priority )( + const Scheduler_Control *, + Thread_Control *, + Priority_Control, + bool + ); + /** @see _Scheduler_Allocate() */ bool ( *allocate )( const Scheduler_Control *, Thread_Control * ); @@ -72,15 +80,6 @@ typedef struct { /** @see _Scheduler_Update() */ void ( *update )( const Scheduler_Control *, Thread_Control * ); - /** @see _Scheduler_Enqueue() */ - void ( *enqueue )( const Scheduler_Control *, Thread_Control * ); - - /** @see _Scheduler_Enqueue_first() */ - void ( *enqueue_first )( const Scheduler_Control *, Thread_Control * ); - - /** @see _Scheduler_Extract() */ - void ( *extract )( const Scheduler_Control *, Thread_Control * ); - /** @see _Scheduler_Priority_compare() */ int ( *priority_compare )( Priority_Control, -- cgit v1.2.3