osfmk/mach/thread_policy.h

   1 /*
   2  * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #ifndef _MACH_THREAD_POLICY_H_
  25 #define _MACH_THREAD_POLICY_H_
  26
  27 #include <mach/mach_types.h>
  28
  29 /*
  30  * These are the calls for accessing the policy parameters
  31  * of a particular thread.
  32  *
  33  * The extra 'get_default' parameter to the second call is
  34  * IN/OUT as follows:
  35  * 1) if asserted on the way in it indicates that the default
  36  * values should be returned, not the ones currently set, in
  37  * this case 'get_default' will always be asserted on return;
  38  * 2) if unasserted on the way in, the current settings are
  39  * desired and if still unasserted on return, then the info
  40  * returned reflects the current settings, otherwise if
  41  * 'get_default' returns asserted, it means that there are no
  42  * current settings due to other parameters taking precedence,
  43  * and the default ones are being returned instead.
  44  */
  45
  46 typedef natural_t       thread_policy_flavor_t;
  47 typedef integer_t       *thread_policy_t;
  48
  49 /*
  50 kern_return_t   thread_policy_set(
  51                                         thread_t                                        thread,
  52                                         thread_policy_flavor_t          flavor,
  53                                         thread_policy_t                         policy_info,
  54                                         mach_msg_type_number_t          count);
  55
  56 kern_return_t   thread_policy_get(
  57                                         thread_t                                        thread,
  58                                         thread_policy_flavor_t          flavor,
  59                                         thread_policy_t                         policy_info,
  60                                         mach_msg_type_number_t          *count,
  61                                         boolean_t                                       *get_default);
  62 */
  63
  64 /*
  65  * Defined flavors.
  66  */
  67 /*
  68  * THREAD_STANDARD_POLICY:
  69  *
  70  * This is the standard (fair) scheduling mode, assigned to new
  71  * threads.  The thread will be given processor time in a manner
  72  * which apportions approximately equal share to long running
  73  * computations.
  74  *
  75  * Parameters:
  76  *      [none]
  77  */
  78
  79 #define THREAD_STANDARD_POLICY                  1
  80
  81 struct thread_standard_policy {
  82         natural_t               no_data;
  83 };
  84
  85 typedef struct thread_standard_policy   thread_standard_policy_data_t;
  86 typedef struct thread_standard_policy   *thread_standard_policy_t;
  87
  88 #define THREAD_STANDARD_POLICY_COUNT    0
  89
  90 /*
  91  * THREAD_EXTENDED_POLICY:
  92  *
  93  * Extended form of THREAD_STANDARD_POLICY, which supplies a
  94  * hint indicating whether this is a long running computation.
  95  *
  96  * Parameters:
  97  *
  98  * timeshare: TRUE (the default) results in identical scheduling
  99  * behavior as THREAD_STANDARD_POLICY.
 100  */
 101
 102 #define THREAD_EXTENDED_POLICY                  1
 103
 104 struct thread_extended_policy {
 105         boolean_t               timeshare;
 106 };
 107
 108 typedef struct thread_extended_policy   thread_extended_policy_data_t;
 109 typedef struct thread_extended_policy   *thread_extended_policy_t;
 110
 111 #define THREAD_EXTENDED_POLICY_COUNT    ((mach_msg_type_number_t) \
 112         (sizeof (thread_extended_policy_data_t) / sizeof (integer_t)))
 113
 114 /*
 115  * THREAD_TIME_CONSTRAINT_POLICY:
 116  *
 117  * This scheduling mode is for threads which have real time
 118  * constraints on their execution.
 119  *
 120  * Parameters:
 121  *
 122  * period: This is the nominal amount of time between separate
 123  * processing arrivals, specified in absolute time units.  A
 124  * value of 0 indicates that there is no inherent periodicity in
 125  * the computation.
 126  *
 127  * computation: This is the nominal amount of computation
 128  * time needed during a separate processing arrival, specified
 129  * in absolute time units.
 130  *
 131  * constraint: This is the maximum amount of real time that
 132  * may elapse from the start of a separate processing arrival
 133  * to the end of computation for logically correct functioning,
 134  * specified in absolute time units.  Must be (>= computation).
 135  * Note that latency = (constraint - computation).
 136  *
 137  * preemptible: This indicates that the computation may be
 138  * interrupted, subject to the constraint specified above.
 139  */
 140
 141 #define THREAD_TIME_CONSTRAINT_POLICY   2
 142
 143 struct thread_time_constraint_policy {
 144         uint32_t                period;
 145         uint32_t                computation;
 146         uint32_t                constraint;
 147         boolean_t               preemptible;
 148 };
 149
 150 typedef struct thread_time_constraint_policy    \
 151                                                                         thread_time_constraint_policy_data_t;
 152 typedef struct thread_time_constraint_policy    \
 153                                                                         *thread_time_constraint_policy_t;
 154
 155 #define THREAD_TIME_CONSTRAINT_POLICY_COUNT     ((mach_msg_type_number_t) \
 156         (sizeof (thread_time_constraint_policy_data_t) / sizeof (integer_t)))
 157
 158 /*
 159  * THREAD_PRECEDENCE_POLICY:
 160  *
 161  * This may be used to indicate the relative value of the
 162  * computation compared to the other threads in the task.
 163  *
 164  * Parameters:
 165  *
 166  * importance: The importance is specified as a signed value.
 167  */
 168
 169 #define THREAD_PRECEDENCE_POLICY                3
 170
 171 struct thread_precedence_policy {
 172         integer_t               importance;
 173 };
 174
 175 typedef struct thread_precedence_policy         thread_precedence_policy_data_t;
 176 typedef struct thread_precedence_policy         *thread_precedence_policy_t;
 177
 178 #define THREAD_PRECEDENCE_POLICY_COUNT  ((mach_msg_type_number_t) \
 179         (sizeof (thread_precedence_policy_data_t) / sizeof (integer_t)))
 180
 181 #endif  /* _MACH_THREAD_POLICY_H_ */