source: rtems/cpukit/score/src/threadtickletimeslice.c @ 6af81435

4.104.114.84.95
Last change on this file since 6af81435 was 05df0a8, checked in by Joel Sherrill <joel.sherrill@…>, on 05/17/99 at 20:41:13

Thread Handler split into multiple files. Eventually, as RTEMS is
split into one function per file, this will decrease the size of executables.

  • Property mode set to 100644
File size: 2.1 KB
Line 
1/*
2 *  Thread Handler
3 *
4 *
5 *  COPYRIGHT (c) 1989-1998.
6 *  On-Line Applications Research Corporation (OAR).
7 *  Copyright assigned to U.S. Government, 1994.
8 *
9 *  The license and distribution terms for this file may be
10 *  found in found in the file LICENSE in this distribution or at
11 *  http://www.OARcorp.com/rtems/license.html.
12 *
13 *  $Id$
14 */
15
16#include <rtems/system.h>
17#include <rtems/score/apiext.h>
18#include <rtems/score/context.h>
19#include <rtems/score/interr.h>
20#include <rtems/score/isr.h>
21#include <rtems/score/object.h>
22#include <rtems/score/priority.h>
23#include <rtems/score/states.h>
24#include <rtems/score/sysstate.h>
25#include <rtems/score/thread.h>
26#include <rtems/score/threadq.h>
27#include <rtems/score/userext.h>
28#include <rtems/score/wkspace.h>
29
30/*PAGE
31 *
32 *  _Thread_Tickle_timeslice
33 *
34 *  This scheduler routine determines if timeslicing is enabled
35 *  for the currently executing thread and, if so, updates the
36 *  timeslice count and checks for timeslice expiration.
37 *
38 *  Input parameters:   NONE
39 *
40 *  Output parameters:  NONE
41 */
42
43void _Thread_Tickle_timeslice( void )
44{
45  Thread_Control *executing;
46
47  executing = _Thread_Executing;
48
49  /*
50   *  Increment the number of ticks this thread has been executing
51   */
52
53  executing->ticks_executed++;
54
55  /*
56   *  If the thread is not preemptible or is not ready, then
57   *  just return.
58   */
59
60  if ( !executing->is_preemptible )
61    return;
62
63  if ( !_States_Is_ready( executing->current_state ) )
64    return;
65
66  /*
67   *  The cpu budget algorithm determines what happens next.
68   */
69
70  switch ( executing->budget_algorithm ) {
71    case THREAD_CPU_BUDGET_ALGORITHM_NONE:
72      break;
73
74    case THREAD_CPU_BUDGET_ALGORITHM_RESET_TIMESLICE:
75    case THREAD_CPU_BUDGET_ALGORITHM_EXHAUST_TIMESLICE:
76      if ( --executing->cpu_time_budget == 0 ) {
77        _Thread_Reset_timeslice();
78        executing->cpu_time_budget = _Thread_Ticks_per_timeslice;
79      }
80      break;
81
82    case THREAD_CPU_BUDGET_ALGORITHM_CALLOUT:
83      if ( --executing->cpu_time_budget == 0 )
84        (*executing->budget_callout)( executing );
85      break;
86  }
87}
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