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  * 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 #ifndef _MACH_THREAD_POLICY_H_
  24 #define _MACH_THREAD_POLICY_H_
  25
  26 #include <mach/mach_types.h>
  27
  28 /*
  29  * These are the calls for accessing the policy parameters
  30  * of a particular thread.
  31  *
  32  * The extra 'get_default' parameter to the second call is
  33  * IN/OUT as follows:
  34  * 1) if asserted on the way in it indicates that the default
  35  * values should be returned, not the ones currently set, in
  36  * this case 'get_default' will always be asserted on return;
  37  * 2) if unasserted on the way in, the current settings are
  38  * desired and if still unasserted on return, then the info
  39  * returned reflects the current settings, otherwise if
  40  * 'get_default' returns asserted, it means that there are no
  41  * current settings due to other parameters taking precedence,
  42  * and the default ones are being returned instead.
  43  */
  44
  45 typedef natural_t       thread_policy_flavor_t;
  46 typedef integer_t       *thread_policy_t;
  47
  48 /*
  49 kern_return_t   thread_policy_set(
  50                                         thread_t                                        thread,
  51                                         thread_policy_flavor_t          flavor,
  52                                         thread_policy_t                         policy_info,
  53                                         mach_msg_type_number_t          count);
  54
  55 kern_return_t   thread_policy_get(
  56                                         thread_t                                        thread,
  57                                         thread_policy_flavor_t          flavor,
  58                                         thread_policy_t                         policy_info,
  59                                         mach_msg_type_number_t          *count,
  60                                         boolean_t                                       *get_default);
  61 */
  62
  63 /*
  64  * Defined flavors.
  65  */
  66 /*
  67  * THREAD_STANDARD_POLICY:
  68  *
  69  * This is the standard (fair) scheduling mode, assigned to new
  70  * threads.  The thread will be given processor time in a manner
  71  * which apportions approximately equal share to long running
  72  * computations.
  73  *
  74  * Parameters:
  75  *      [none]
  76  */
  77
  78 #define THREAD_STANDARD_POLICY                  1
  79
  80 struct thread_standard_policy {
  81         natural_t               no_data;
  82 };
  83
  84 typedef struct thread_standard_policy   thread_standard_policy_data_t;
  85 typedef struct thread_standard_policy   *thread_standard_policy_t;
  86
  87 #define THREAD_STANDARD_POLICY_COUNT    0
  88
  89 /*
  90  * THREAD_EXTENDED_POLICY:
  91  *
  92  * Extended form of THREAD_STANDARD_POLICY, which supplies a
  93  * hint indicating whether this is a long running computation.
  94  *
  95  * Parameters:
  96  *
  97  * timeshare: TRUE (the default) results in identical scheduling
  98  * behavior as THREAD_STANDARD_POLICY.
  99  */
 100
 101 #define THREAD_EXTENDED_POLICY                  1
 102
 103 struct thread_extended_policy {
 104         boolean_t               timeshare;
 105 };
 106
 107 typedef struct thread_extended_policy   thread_extended_policy_data_t;
 108 typedef struct thread_extended_policy   *thread_extended_policy_t;
 109
 110 #define THREAD_EXTENDED_POLICY_COUNT    ((mach_msg_type_number_t) \
 111         (sizeof (thread_extended_policy_data_t) / sizeof (integer_t)))
 112
 113 /*
 114  * THREAD_TIME_CONSTRAINT_POLICY:
 115  *
 116  * This scheduling mode is for threads which have real time
 117  * constraints on their execution.
 118  *
 119  * Parameters:
 120  *
 121  * period: This is the nominal amount of time between separate
 122  * processing arrivals, specified in absolute time units.  A
 123  * value of 0 indicates that there is no inherent periodicity in
 124  * the computation.
 125  *
 126  * computation: This is the nominal amount of computation
 127  * time needed during a separate processing arrival, specified
 128  * in absolute time units.
 129  *
 130  * constraint: This is the maximum amount of real time that
 131  * may elapse from the start of a separate processing arrival
 132  * to the end of computation for logically correct functioning,
 133  * specified in absolute time units.  Must be (>= computation).
 134  * Note that latency = (constraint - computation).
 135  *
 136  * preemptible: This indicates that the computation may be
 137  * interrupted, subject to the constraint specified above.
 138  */
 139
 140 #define THREAD_TIME_CONSTRAINT_POLICY   2
 141
 142 struct thread_time_constraint_policy {
 143         uint32_t                period;
 144         uint32_t                computation;
 145         uint32_t                constraint;
 146         boolean_t               preemptible;
 147 };
 148
 149 typedef struct thread_time_constraint_policy    \
 150                                                                         thread_time_constraint_policy_data_t;
 151 typedef struct thread_time_constraint_policy    \
 152                                                                         *thread_time_constraint_policy_t;
 153
 154 #define THREAD_TIME_CONSTRAINT_POLICY_COUNT     ((mach_msg_type_number_t) \
 155         (sizeof (thread_time_constraint_policy_data_t) / sizeof (integer_t)))
 156
 157 /*
 158  * THREAD_PRECEDENCE_POLICY:
 159  *
 160  * This may be used to indicate the relative value of the
 161  * computation compared to the other threads in the task.
 162  *
 163  * Parameters:
 164  *
 165  * importance: The importance is specified as a signed value.
 166  */
 167
 168 #define THREAD_PRECEDENCE_POLICY                3
 169
 170 struct thread_precedence_policy {
 171         integer_t               importance;
 172 };
 173
 174 typedef struct thread_precedence_policy         thread_precedence_policy_data_t;
 175 typedef struct thread_precedence_policy         *thread_precedence_policy_t;
 176
 177 #define THREAD_PRECEDENCE_POLICY_COUNT  ((mach_msg_type_number_t) \
 178         (sizeof (thread_precedence_policy_data_t) / sizeof (integer_t)))
 179
 180 #endif  /* _MACH_THREAD_POLICY_H_ */