Changeset f39f667a in rtems for doc


Ignore:
Timestamp:
May 14, 2014, 11:50:48 AM (6 years ago)
Author:
Sebastian Huber <sebastian.huber@…>
Branches:
4.11, master
Children:
3733b224
Parents:
2369b10
git-author:
Sebastian Huber <sebastian.huber@…> (05/14/14 11:50:48)
git-committer:
Sebastian Huber <sebastian.huber@…> (05/15/14 10:18:44)
Message:

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.

File:
1 edited

Legend:

Unmodified
Added
Removed
  • doc/user/glossary.texi

    r2369b10 rf39f667a  
    278278A special low priority task which assumes
    279279control of the CPU when no other task is able to execute.
    280 
    281 @item in the air task
    282 A task is @dfn{in the air} if it is in a transient state and has a processor
    283 assigned.  The next scheduler operation will turn it into a blocked, ready or
    284 scheduled task.  This state is specific to SMP configurations.
    285280
    286281@item interface
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