osfmk/mach/thread_policy.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
  24  *
  25  * HISTORY
  26  *
  27  * 10 October 2000 (debo)
  28  *  Created.
  29  *
  30  * 30 November 2000 (debo)
  31  *      Final resolution of review feedback.
  32  */
  33
  34 #ifndef _MACH_THREAD_POLICY_H_
  35 #define _MACH_THREAD_POLICY_H_
  36
  37 #include <mach/mach_types.h>
  38
  39 /*
  40  * These are the calls for accessing the policy parameters
  41  * of a particular thread.
  42  *
  43  * The extra 'get_default' parameter to the second call is
  44  * IN/OUT as follows:
  45  * 1) if asserted on the way in it indicates that the default
  46  * values should be returned, not the ones currently set, in
  47  * this case 'get_default' will always be asserted on return;
  48  * 2) if unasserted on the way in, the current settings are
  49  * desired and if still unasserted on return, then the info
  50  * returned reflects the current settings, otherwise if
  51  * 'get_default' returns asserted, it means that there are no
  52  * current settings due to other parameters taking precedence,
  53  * and the default ones are being returned instead.
  54  */
  55
  56 typedef natural_t       thread_policy_flavor_t;
  57 typedef integer_t       *thread_policy_t;
  58
  59 /*
  60 kern_return_t   thread_policy_set(
  61                                         thread_act_t                            thread,
  62                                         thread_policy_flavor_t          flavor,
  63                                         thread_policy_t                         policy_info,
  64                                         mach_msg_type_number_t          count);
  65
  66 kern_return_t   thread_policy_get(
  67                                         thread_act_t                            thread,
  68                                         thread_policy_flavor_t          flavor,
  69                                         thread_policy_t                         policy_info,
  70                                         mach_msg_type_number_t          *count,
  71                                         boolean_t                                       *get_default);
  72 */
  73
  74 /*
  75  * Defined flavors.
  76  */
  77 /*
  78  * THREAD_STANDARD_POLICY:
  79  *
  80  * This is the standard [fair] scheduling mode, assigned to new
  81  * threads.  Specifying it explicitly is not typically required,
  82  * but may be used to return a thread to the default mode setting.
  83  *
  84  * Parameters:
  85  *      [none]
  86  */
  87
  88 #define THREAD_STANDARD_POLICY                  1
  89
  90 struct thread_standard_policy {
  91         /* no data */
  92 };
  93
  94 typedef struct thread_standard_policy   thread_standard_policy_data_t;
  95 typedef struct thread_standard_policy   *thread_standard_policy_t;
  96
  97 #define THREAD_STANDARD_POLICY_COUNT    \
  98         (sizeof (thread_standard_policy_data_t) / sizeof (integer_t))
  99
 100 /*
 101  * THREAD_TIME_CONSTRAINT_POLICY:
 102  *
 103  * This scheduling mode is for threads which have real time
 104  * constraints on their execution.
 105  *
 106  * Parameters:
 107  *
 108  * period: This is the nominal amount of time between separate
 109  * processing arrivals, specified in absolute time units.  A
 110  * value of 0 indicates that there is no inherent periodicity in
 111  * the computation.
 112  *
 113  * computation: This is the nominal amount of computation
 114  * time needed during a separate processing arrival, specified
 115  * in absolute time units.
 116  *
 117  * constraint: This is the maximum amount of real time that
 118  * may elapse from the start of a separate processing arrival
 119  * to the end of computation for logically correct functioning,
 120  * specified in absolute time units.  Must be (>= computation).
 121  * Note that latency = (constraint - computation).
 122  *
 123  * preemptible: This indicates that the computation may be
 124  * interrupted, subject to the constraint specified above.
 125  */
 126
 127 #define THREAD_TIME_CONSTRAINT_POLICY   2
 128
 129 struct thread_time_constraint_policy {
 130         natural_t               period;
 131         natural_t               computation;
 132         natural_t               constraint;
 133         boolean_t               preemptible;
 134 };
 135
 136 typedef struct thread_time_constraint_policy    \
 137                                                                         thread_time_constraint_policy_data_t;
 138 typedef struct thread_time_constraint_policy    \
 139                                                                         *thread_time_constraint_policy_t;
 140
 141 #define THREAD_TIME_CONSTRAINT_POLICY_COUNT     \
 142         (sizeof (thread_time_constraint_policy_data_t) / sizeof (integer_t))
 143
 144 /*
 145  * THREAD_PRECEDENCE_POLICY:
 146  *
 147  * This may be used to indicate the relative value of the
 148  * computation compared to the other threads in the task.
 149  *
 150  * Parameters:
 151  *
 152  * importance: The importance is specified as a signed value.
 153  */
 154
 155 #define THREAD_PRECEDENCE_POLICY                3
 156
 157 struct thread_precedence_policy {
 158         integer_t               importance;
 159 };
 160
 161 typedef struct thread_precedence_policy         thread_precedence_policy_data_t;
 162 typedef struct thread_precedence_policy         *thread_precedence_policy_t;
 163
 164 #define THREAD_PRECEDENCE_POLICY_COUNT  \
 165         (sizeof (thread_precedence_policy_data_t) / sizeof (integer_t))
 166
 167 #endif  /* _MACH_THREAD_POLICY_H_ */