osfmk/mach/thread_policy.h

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