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. --- doc/user/glossary.texi | 5 ----- 1 file changed, 5 deletions(-) (limited to 'doc/user/glossary.texi') diff --git a/doc/user/glossary.texi b/doc/user/glossary.texi index 0aafa69186..cff7028cb7 100644 --- a/doc/user/glossary.texi +++ b/doc/user/glossary.texi @@ -278,11 +278,6 @@ access an active object. A special low priority task which assumes control of the CPU when no other task is able to execute. -@item in the air task -A task is @dfn{in the air} if it is in a transient state and has a processor -assigned. The next scheduler operation will turn it into a blocked, ready or -scheduled task. This state is specific to SMP configurations. - @item interface A specification of the methodology used to connect multiple independent subsystems. -- cgit v1.2.3