osfmk/kern/sched.h

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
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   8  * Version 2.0 (the 'License'). You may not use this file except in
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  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
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  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
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  25  * Please see the License for the specific language governing rights and
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  29  */
  30 /*
  31  * @OSF_COPYRIGHT@
  32  */
  33 /*
  34  * Mach Operating System
  35  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  36  * All Rights Reserved.
  37  *
  38  * Permission to use, copy, modify and distribute this software and its
  39  * documentation is hereby granted, provided that both the copyright
  40  * notice and this permission notice appear in all copies of the
  41  * software, derivative works or modified versions, and any portions
  42  * thereof, and that both notices appear in supporting documentation.
  43  *
  44  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  45  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  46  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  47  *
  48  * Carnegie Mellon requests users of this software to return to
  49  *
  50  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  51  *  School of Computer Science
  52  *  Carnegie Mellon University
  53  *  Pittsburgh PA 15213-3890
  54  *
  55  * any improvements or extensions that they make and grant Carnegie Mellon
  56  * the rights to redistribute these changes.
  57  */
  58 /*
  59  */
  60 /*
  61  *      File:   sched.h
  62  *      Author: Avadis Tevanian, Jr.
  63  *      Date:   1985
  64  *
  65  *      Header file for scheduler.
  66  *
  67  */
  68
  69 #ifndef _KERN_SCHED_H_
  70 #define _KERN_SCHED_H_
  71
  72 #include <stat_time.h>
  73
  74 #include <mach/policy.h>
  75 #include <kern/kern_types.h>
  76 #include <kern/queue.h>
  77 #include <kern/lock.h>
  78 #include <kern/macro_help.h>
  79 #include <kern/timer_call.h>
  80 #include <kern/ast.h>
  81
  82 #define NRQS            128                             /* 128 levels per run queue */
  83 #define NRQBM           (NRQS / 32)             /* number of words per bit map */
  84
  85 #define MAXPRI          (NRQS-1)
  86 #define MINPRI          IDLEPRI                 /* lowest legal priority schedulable */
  87 #define IDLEPRI         0                               /* idle thread priority */
  88 #define DEPRESSPRI      MINPRI                  /* depress priority */
  89
  90 /*
  91  *      High-level priority assignments
  92  *
  93  *************************************************************************
  94  * 127          Reserved (real-time)
  95  *                              A
  96  *                              +
  97  *                      (32 levels)
  98  *                              +
  99  *                              V
 100  * 96           Reserved (real-time)
 101  * 95           Kernel mode only
 102  *                              A
 103  *                              +
 104  *                      (16 levels)
 105  *                              +
 106  *                              V
 107  * 80           Kernel mode only
 108  * 79           System high priority
 109  *                              A
 110  *                              +
 111  *                      (16 levels)
 112  *                              +
 113  *                              V
 114  * 64           System high priority
 115  * 63           Elevated priorities
 116  *                              A
 117  *                              +
 118  *                      (12 levels)
 119  *                              +
 120  *                              V
 121  * 52           Elevated priorities
 122  * 51           Elevated priorities (incl. BSD +nice)
 123  *                              A
 124  *                              +
 125  *                      (20 levels)
 126  *                              +
 127  *                              V
 128  * 32           Elevated priorities (incl. BSD +nice)
 129  * 31           Default (default base for threads)
 130  * 30           Lowered priorities (incl. BSD -nice)
 131  *                              A
 132  *                              +
 133  *                      (20 levels)
 134  *                              +
 135  *                              V
 136  * 11           Lowered priorities (incl. BSD -nice)
 137  * 10           Lowered priorities (aged pri's)
 138  *                              A
 139  *                              +
 140  *                      (11 levels)
 141  *                              +
 142  *                              V
 143  * 0            Lowered priorities (aged pri's / idle)
 144  *************************************************************************
 145  */
 146
 147 #define BASEPRI_RTQUEUES        (BASEPRI_REALTIME + 1)                          /* 97 */
 148 #define BASEPRI_REALTIME        (MAXPRI - (NRQS / 4) + 1)                       /* 96 */
 149
 150 #define MAXPRI_KERNEL           (BASEPRI_REALTIME - 1)                          /* 95 */
 151 #define BASEPRI_PREEMPT         (MAXPRI_KERNEL - 2)                                     /* 93 */
 152 #define BASEPRI_KERNEL          (MINPRI_KERNEL + 1)                                     /* 81 */
 153 #define MINPRI_KERNEL           (MAXPRI_KERNEL - (NRQS / 8) + 1)        /* 80 */
 154
 155 #define MAXPRI_RESERVED         (MINPRI_KERNEL - 1)                                     /* 79 */
 156 #define MINPRI_RESERVED         (MAXPRI_RESERVED - (NRQS / 8) + 1)      /* 64 */
 157
 158 #define MAXPRI_USER                     (MINPRI_RESERVED - 1)                           /* 63 */
 159 #define BASEPRI_CONTROL         (BASEPRI_DEFAULT + 17)                          /* 48 */
 160 #define BASEPRI_FOREGROUND      (BASEPRI_DEFAULT + 16)                          /* 47 */
 161 #define BASEPRI_BACKGROUND      (BASEPRI_DEFAULT + 15)                          /* 46 */
 162 #define BASEPRI_DEFAULT         (MAXPRI_USER - (NRQS / 4))                      /* 31 */
 163 #define MINPRI_USER                     MINPRI                                                          /*  0 */
 164
 165 /*
 166  *      Macro to check for invalid priorities.
 167  */
 168 #define invalid_pri(pri) ((pri) < MINPRI || (pri) > MAXPRI)
 169
 170 struct run_queue {
 171         int                                     highq;                          /* highest runnable queue */
 172         int                                     bitmap[NRQBM];          /* run queue bitmap array */
 173         int                                     count;                          /* # of threads total */
 174         int                                     urgency;                        /* level of preemption urgency */
 175         queue_head_t            queues[NRQS];           /* one for each priority */
 176 };
 177
 178 typedef struct run_queue        *run_queue_t;
 179 #define RUN_QUEUE_NULL          ((run_queue_t) 0)
 180
 181 #define first_timeslice(processor)              ((processor)->timeslice > 0)
 182
 183 #define processor_timeslice_setup(processor, thread)                    \
 184 MACRO_BEGIN                                                                                                             \
 185         (processor)->timeslice =                                                                        \
 186                 ((thread)->sched_mode & TH_MODE_TIMESHARE)?                             \
 187                         (processor)->processor_set->timeshare_quanta: 1;        \
 188 MACRO_END
 189
 190 #define thread_quantum_init(thread)                                                     \
 191 MACRO_BEGIN                                                                                                     \
 192         (thread)->current_quantum =                                                     \
 193                 ((thread)->sched_mode & TH_MODE_REALTIME)?                      \
 194                         (thread)->realtime.computation: std_quantum;    \
 195 MACRO_END
 196
 197 /* Invoked at splsched by a thread on itself */
 198 #define csw_needed(thread, processor) (                                                                         \
 199         ((thread)->state & TH_SUSP)                                                                             ||              \
 200         (first_timeslice(processor)?                                                                                    \
 201          ((processor)->runq.highq > (thread)->sched_pri                         ||                      \
 202           (processor)->processor_set->runq.highq > (thread)->sched_pri) :               \
 203          ((processor)->runq.highq >= (thread)->sched_pri                        ||                      \
 204           (processor)->processor_set->runq.highq >= (thread)->sched_pri))       )
 205
 206 /*
 207  *      Scheduler routines.
 208  */
 209
 210 /* Remove thread from its run queue */
 211 extern run_queue_t      run_queue_remove(
 212                                                 thread_t        thread);
 213
 214 /* Handle quantum expiration for an executing thread */
 215 extern void             thread_quantum_expire(
 216                                         timer_call_param_t      processor,
 217                                         timer_call_param_t      thread);
 218
 219 /* Called at splsched by a thread on itself */
 220 extern ast_t    csw_check(
 221                                         thread_t                thread,
 222                                         processor_t             processor);
 223
 224 extern uint32_t std_quantum, min_std_quantum;
 225 extern uint32_t std_quantum_us;
 226
 227 extern uint32_t max_rt_quantum, min_rt_quantum;
 228
 229 extern uint32_t sched_cswtime;
 230
 231 /*
 232  *      Age usage (1 << SCHED_TICK_SHIFT) times per second.
 233  */
 234 #define SCHED_TICK_SHIFT        3
 235
 236 extern unsigned         sched_tick;
 237 extern uint32_t         sched_tick_interval;
 238
 239 /* Periodic computation of various averages */
 240 extern void             compute_averages(void);
 241
 242 extern void             compute_averunnable(
 243                                         void                    *nrun);
 244
 245 extern void             compute_stack_target(
 246                                         void                    *arg);
 247
 248 /*
 249  *      Conversion factor from usage
 250  *      to priority.
 251  */
 252 extern uint32_t         sched_pri_shift;
 253
 254 /*
 255  *      Scaling factor for usage
 256  *      based on load.
 257  */
 258 extern int8_t           sched_load_shifts[NRQS];
 259
 260 extern int32_t          sched_poll_yield_shift;
 261 extern uint32_t         sched_safe_duration;
 262
 263 extern uint64_t         max_unsafe_computation;
 264 extern uint64_t         max_poll_computation;
 265
 266 extern uint32_t         avenrun[3], mach_factor[3];
 267
 268 /*
 269  *      thread_timer_delta macro takes care of both thread timers.
 270  */
 271 #define thread_timer_delta(thread, delta)                                       \
 272 MACRO_BEGIN                                                                                                     \
 273         (delta) = timer_delta(&(thread)->system_timer,                  \
 274                                                         &(thread)->system_timer_save);  \
 275         (delta) += timer_delta(&(thread)->user_timer,                   \
 276                                                         &(thread)->user_timer_save);    \
 277 MACRO_END
 278
 279 #endif  /* _KERN_SCHED_H_ */