osfmk/mach/thread_policy.h

   1 /*
   2  * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30
  31 #ifndef _MACH_THREAD_POLICY_H_
  32 #define _MACH_THREAD_POLICY_H_
  33
  34 #include <mach/mach_types.h>
  35
  36 /*
  37  * These are the calls for accessing the policy parameters
  38  * of a particular thread.
  39  *
  40  * The extra 'get_default' parameter to the second call is
  41  * IN/OUT as follows:
  42  * 1) if asserted on the way in it indicates that the default
  43  * values should be returned, not the ones currently set, in
  44  * this case 'get_default' will always be asserted on return;
  45  * 2) if unasserted on the way in, the current settings are
  46  * desired and if still unasserted on return, then the info
  47  * returned reflects the current settings, otherwise if
  48  * 'get_default' returns asserted, it means that there are no
  49  * current settings due to other parameters taking precedence,
  50  * and the default ones are being returned instead.
  51  */
  52
  53 typedef natural_t       thread_policy_flavor_t;
  54 typedef integer_t       *thread_policy_t;
  55
  56 /*
  57 kern_return_t   thread_policy_set(
  58                                         thread_t                                        thread,
  59                                         thread_policy_flavor_t          flavor,
  60                                         thread_policy_t                         policy_info,
  61                                         mach_msg_type_number_t          count);
  62
  63 kern_return_t   thread_policy_get(
  64                                         thread_t                                        thread,
  65                                         thread_policy_flavor_t          flavor,
  66                                         thread_policy_t                         policy_info,
  67                                         mach_msg_type_number_t          *count,
  68                                         boolean_t                                       *get_default);
  69 */
  70
  71 /*
  72  * Defined flavors.
  73  */
  74 /*
  75  * THREAD_STANDARD_POLICY:
  76  *
  77  * This is the standard (fair) scheduling mode, assigned to new
  78  * threads.  The thread will be given processor time in a manner
  79  * which apportions approximately equal share to long running
  80  * computations.
  81  *
  82  * Parameters:
  83  *      [none]
  84  */
  85
  86 #define THREAD_STANDARD_POLICY                  1
  87
  88 struct thread_standard_policy {
  89         natural_t               no_data;
  90 };
  91
  92 typedef struct thread_standard_policy   thread_standard_policy_data_t;
  93 typedef struct thread_standard_policy   *thread_standard_policy_t;
  94
  95 #define THREAD_STANDARD_POLICY_COUNT    0
  96
  97 /*
  98  * THREAD_EXTENDED_POLICY:
  99  *
 100  * Extended form of THREAD_STANDARD_POLICY, which supplies a
 101  * hint indicating whether this is a long running computation.
 102  *
 103  * Parameters:
 104  *
 105  * timeshare: TRUE (the default) results in identical scheduling
 106  * behavior as THREAD_STANDARD_POLICY.
 107  */
 108
 109 #define THREAD_EXTENDED_POLICY                  1
 110
 111 struct thread_extended_policy {
 112         boolean_t               timeshare;
 113 };
 114
 115 typedef struct thread_extended_policy   thread_extended_policy_data_t;
 116 typedef struct thread_extended_policy   *thread_extended_policy_t;
 117
 118 #define THREAD_EXTENDED_POLICY_COUNT    ((mach_msg_type_number_t) \
 119         (sizeof (thread_extended_policy_data_t) / sizeof (integer_t)))
 120
 121 /*
 122  * THREAD_TIME_CONSTRAINT_POLICY:
 123  *
 124  * This scheduling mode is for threads which have real time
 125  * constraints on their execution.
 126  *
 127  * Parameters:
 128  *
 129  * period: This is the nominal amount of time between separate
 130  * processing arrivals, specified in absolute time units.  A
 131  * value of 0 indicates that there is no inherent periodicity in
 132  * the computation.
 133  *
 134  * computation: This is the nominal amount of computation
 135  * time needed during a separate processing arrival, specified
 136  * in absolute time units.
 137  *
 138  * constraint: This is the maximum amount of real time that
 139  * may elapse from the start of a separate processing arrival
 140  * to the end of computation for logically correct functioning,
 141  * specified in absolute time units.  Must be (>= computation).
 142  * Note that latency = (constraint - computation).
 143  *
 144  * preemptible: This indicates that the computation may be
 145  * interrupted, subject to the constraint specified above.
 146  */
 147
 148 #define THREAD_TIME_CONSTRAINT_POLICY   2
 149
 150 struct thread_time_constraint_policy {
 151         uint32_t                period;
 152         uint32_t                computation;
 153         uint32_t                constraint;
 154         boolean_t               preemptible;
 155 };
 156
 157 typedef struct thread_time_constraint_policy    \
 158                                                                         thread_time_constraint_policy_data_t;
 159 typedef struct thread_time_constraint_policy    \
 160                                                                         *thread_time_constraint_policy_t;
 161
 162 #define THREAD_TIME_CONSTRAINT_POLICY_COUNT     ((mach_msg_type_number_t) \
 163         (sizeof (thread_time_constraint_policy_data_t) / sizeof (integer_t)))
 164
 165 /*
 166  * THREAD_PRECEDENCE_POLICY:
 167  *
 168  * This may be used to indicate the relative value of the
 169  * computation compared to the other threads in the task.
 170  *
 171  * Parameters:
 172  *
 173  * importance: The importance is specified as a signed value.
 174  */
 175
 176 #define THREAD_PRECEDENCE_POLICY                3
 177
 178 struct thread_precedence_policy {
 179         integer_t               importance;
 180 };
 181
 182 typedef struct thread_precedence_policy         thread_precedence_policy_data_t;
 183 typedef struct thread_precedence_policy         *thread_precedence_policy_t;
 184
 185 #define THREAD_PRECEDENCE_POLICY_COUNT  ((mach_msg_type_number_t) \
 186         (sizeof (thread_precedence_policy_data_t) / sizeof (integer_t)))
 187
 188 #endif  /* _MACH_THREAD_POLICY_H_ */