source: rtems/cpukit/score/src/scheduleredfchangepriority.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: 898 bytes
Line 
1/**
2 *  @file
3 *
4 *  @brief Scheduler EDF Extract
5 *  @ingroup ScoreScheduler
6 */
7
8/*
9 *  Copyright (C) 2011 Petr Benes.
10 *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
11 *
12 *  The license and distribution terms for this file may be
13 *  found in the file LICENSE in this distribution or at
14 *  http://www.rtems.org/license/LICENSE.
15 */
16
17#if HAVE_CONFIG_H
18#include "config.h"
19#endif
20
21#include <rtems/score/scheduleredfimpl.h>
22
23void _Scheduler_EDF_Change_priority(
24  const Scheduler_Control *scheduler,
25  Thread_Control          *the_thread,
26  Priority_Control         new_priority,
27  bool                     prepend_it
28)
29{
30  Scheduler_EDF_Context *context =
31    _Scheduler_EDF_Get_context( scheduler );
32  Scheduler_EDF_Node *node = _Scheduler_EDF_Node_get( the_thread );
33
34  _RBTree_Extract( &context->Ready, &node->Node );
35  _RBTree_Insert( &context->Ready, &node->Node );
36}
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