source: rtems/cpukit/score/src/schedulersimplechangepriority.c @ 25f5730f

4.115
Last change on this file since 25f5730f was f39f667a, checked in by Sebastian Huber <sebastian.huber@…>, on 05/14/14 at 11:50:48

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.
  • Property mode set to 100644
File size: 970 bytes
RevLine 
[8396c18e]1/**
2 * @file
[0118ed6]3 *
[f39f667a]4 * @brief Removes a Thread from the Simple Queue
5 *
[8396c18e]6 * @ingroup ScoreScheduler
7 */
8
9/*
[0118ed6]10 *  COPYRIGHT (c) 2011.
11 *  On-Line Applications Research Corporation (OAR).
12 *
13 *  The license and distribution terms for this file may be
14 *  found in the file LICENSE in this distribution or at
[c499856]15 *  http://www.rtems.org/license/LICENSE.
[0118ed6]16 */
17
18#if HAVE_CONFIG_H
19#include "config.h"
20#endif
21
[bd5606ab]22#include <rtems/score/schedulersimpleimpl.h>
[0118ed6]23
[f39f667a]24void _Scheduler_simple_Change_priority(
[e1598a6]25  const Scheduler_Control *scheduler,
[f39f667a]26  Thread_Control          *the_thread,
27  Priority_Control         new_priority,
28  bool                     prepend_it
[0118ed6]29)
30{
[e1598a6]31  Scheduler_simple_Context *context =
32    _Scheduler_simple_Get_context( scheduler );
[0118ed6]33
[f39f667a]34  _Scheduler_simple_Extract( scheduler, the_thread );
35
36  if ( prepend_it ) {
37    _Scheduler_simple_Insert_priority_lifo( &context->Ready, the_thread );
38  } else {
39    _Scheduler_simple_Insert_priority_fifo( &context->Ready, the_thread );
40  }
[0118ed6]41}
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