osfmk/mach/thread_policy.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
  27  *
  28  * HISTORY
  29  *
  30  * 10 October 2000 (debo)
  31  *  Created.
  32  *
  33  * 30 November 2000 (debo)
  34  *      Final resolution of review feedback.
  35  */
  36
  37 #ifndef _MACH_THREAD_POLICY_H_
  38 #define _MACH_THREAD_POLICY_H_
  39
  40 #include <mach/mach_types.h>
  41
  42 /*
  43  * These are the calls for accessing the policy parameters
  44  * of a particular thread.
  45  *
  46  * The extra 'get_default' parameter to the second call is
  47  * IN/OUT as follows:
  48  * 1) if asserted on the way in it indicates that the default
  49  * values should be returned, not the ones currently set, in
  50  * this case 'get_default' will always be asserted on return;
  51  * 2) if unasserted on the way in, the current settings are
  52  * desired and if still unasserted on return, then the info
  53  * returned reflects the current settings, otherwise if
  54  * 'get_default' returns asserted, it means that there are no
  55  * current settings due to other parameters taking precedence,
  56  * and the default ones are being returned instead.
  57  */
  58
  59 typedef natural_t       thread_policy_flavor_t;
  60 typedef integer_t       *thread_policy_t;
  61
  62 /*
  63 kern_return_t   thread_policy_set(
  64                                         thread_act_t                            thread,
  65                                         thread_policy_flavor_t          flavor,
  66                                         thread_policy_t                         policy_info,
  67                                         mach_msg_type_number_t          count);
  68
  69 kern_return_t   thread_policy_get(
  70                                         thread_act_t                            thread,
  71                                         thread_policy_flavor_t          flavor,
  72                                         thread_policy_t                         policy_info,
  73                                         mach_msg_type_number_t          *count,
  74                                         boolean_t                                       *get_default);
  75 */
  76
  77 /*
  78  * Defined flavors.
  79  */
  80 /*
  81  * THREAD_STANDARD_POLICY:
  82  *
  83  * This is the standard (fair) scheduling mode, assigned to new
  84  * threads.  The thread will be given processor time in a manner
  85  * which apportions approximately equal share to long running
  86  * computations.
  87  *
  88  * Parameters:
  89  *      [none]
  90  */
  91
  92 #define THREAD_STANDARD_POLICY                  1
  93
  94 struct thread_standard_policy {
  95         natural_t               no_data;
  96 };
  97
  98 typedef struct thread_standard_policy   thread_standard_policy_data_t;
  99 typedef struct thread_standard_policy   *thread_standard_policy_t;
 100
 101 #define THREAD_STANDARD_POLICY_COUNT    0
 102
 103 /*
 104  * THREAD_EXTENDED_POLICY:
 105  *
 106  * Extended form of THREAD_STANDARD_POLICY, which supplies a
 107  * hint indicating whether this is a long running computation.
 108  *
 109  * Parameters:
 110  *
 111  * timeshare: TRUE (the default) results in identical scheduling
 112  * behavior as THREAD_STANDARD_POLICY.
 113  */
 114
 115 #define THREAD_EXTENDED_POLICY                  1
 116
 117 struct thread_extended_policy {
 118         boolean_t               timeshare;
 119 };
 120
 121 typedef struct thread_extended_policy   thread_extended_policy_data_t;
 122 typedef struct thread_extended_policy   *thread_extended_policy_t;
 123
 124 #define THREAD_EXTENDED_POLICY_COUNT    \
 125         (sizeof (thread_extended_policy_data_t) / sizeof (integer_t))
 126
 127 /*
 128  * THREAD_TIME_CONSTRAINT_POLICY:
 129  *
 130  * This scheduling mode is for threads which have real time
 131  * constraints on their execution.
 132  *
 133  * Parameters:
 134  *
 135  * period: This is the nominal amount of time between separate
 136  * processing arrivals, specified in absolute time units.  A
 137  * value of 0 indicates that there is no inherent periodicity in
 138  * the computation.
 139  *
 140  * computation: This is the nominal amount of computation
 141  * time needed during a separate processing arrival, specified
 142  * in absolute time units.
 143  *
 144  * constraint: This is the maximum amount of real time that
 145  * may elapse from the start of a separate processing arrival
 146  * to the end of computation for logically correct functioning,
 147  * specified in absolute time units.  Must be (>= computation).
 148  * Note that latency = (constraint - computation).
 149  *
 150  * preemptible: This indicates that the computation may be
 151  * interrupted, subject to the constraint specified above.
 152  */
 153
 154 #define THREAD_TIME_CONSTRAINT_POLICY   2
 155
 156 struct thread_time_constraint_policy {
 157         uint32_t                period;
 158         uint32_t                computation;
 159         uint32_t                constraint;
 160         boolean_t               preemptible;
 161 };
 162
 163 typedef struct thread_time_constraint_policy    \
 164                                                                         thread_time_constraint_policy_data_t;
 165 typedef struct thread_time_constraint_policy    \
 166                                                                         *thread_time_constraint_policy_t;
 167
 168 #define THREAD_TIME_CONSTRAINT_POLICY_COUNT     \
 169         (sizeof (thread_time_constraint_policy_data_t) / sizeof (integer_t))
 170
 171 /*
 172  * THREAD_PRECEDENCE_POLICY:
 173  *
 174  * This may be used to indicate the relative value of the
 175  * computation compared to the other threads in the task.
 176  *
 177  * Parameters:
 178  *
 179  * importance: The importance is specified as a signed value.
 180  */
 181
 182 #define THREAD_PRECEDENCE_POLICY                3
 183
 184 struct thread_precedence_policy {
 185         integer_t               importance;
 186 };
 187
 188 typedef struct thread_precedence_policy         thread_precedence_policy_data_t;
 189 typedef struct thread_precedence_policy         *thread_precedence_policy_t;
 190
 191 #define THREAD_PRECEDENCE_POLICY_COUNT  \
 192         (sizeof (thread_precedence_policy_data_t) / sizeof (integer_t))
 193
 194 #endif  /* _MACH_THREAD_POLICY_H_ */