osfmk/kern/sched.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * @OSF_COPYRIGHT@
  27  */
  28 /*
  29  * Mach Operating System
  30  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  31  * All Rights Reserved.
  32  *
  33  * Permission to use, copy, modify and distribute this software and its
  34  * documentation is hereby granted, provided that both the copyright
  35  * notice and this permission notice appear in all copies of the
  36  * software, derivative works or modified versions, and any portions
  37  * thereof, and that both notices appear in supporting documentation.
  38  *
  39  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  40  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  41  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  42  *
  43  * Carnegie Mellon requests users of this software to return to
  44  *
  45  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  46  *  School of Computer Science
  47  *  Carnegie Mellon University
  48  *  Pittsburgh PA 15213-3890
  49  *
  50  * any improvements or extensions that they make and grant Carnegie Mellon
  51  * the rights to redistribute these changes.
  52  */
  53 /*
  54  */
  55 /*
  56  *      File:   sched.h
  57  *      Author: Avadis Tevanian, Jr.
  58  *      Date:   1985
  59  *
  60  *      Header file for scheduler.
  61  *
  62  */
  63
  64 #ifndef _KERN_SCHED_H_
  65 #define _KERN_SCHED_H_
  66
  67 #include <simple_clock.h>
  68 #include <stat_time.h>
  69
  70 #include <mach/policy.h>
  71 #include <kern/kern_types.h>
  72 #include <kern/queue.h>
  73 #include <kern/lock.h>
  74 #include <kern/macro_help.h>
  75 #include <kern/timer_call.h>
  76 #include <kern/ast.h>
  77
  78 #if     STAT_TIME
  79
  80 /*
  81  *      Statistical timing uses microseconds as timer units.
  82  */
  83 #define PRI_SHIFT       (16 - SCHED_TICK_SHIFT)
  84
  85 #else   /* STAT_TIME */
  86
  87 /*
  88  *      Otherwise machine provides shift(s) based on time units it uses.
  89  */
  90 #include <machine/sched_param.h>
  91
  92 #endif  /* STAT_TIME */
  93
  94 #define NRQS            128                             /* 128 levels per run queue */
  95 #define NRQBM           (NRQS / 32)             /* number of words per bit map */
  96
  97 #define MAXPRI          (NRQS-1)
  98 #define MINPRI          IDLEPRI                 /* lowest legal priority schedulable */
  99 #define IDLEPRI         0                               /* idle thread priority */
 100 #define DEPRESSPRI      MINPRI                  /* depress priority */
 101
 102 /*
 103  *      High-level priority assignments
 104  *
 105  *************************************************************************
 106  * 127          Reserved (real-time)
 107  *                              A
 108  *                              +
 109  *                      (32 levels)
 110  *                              +
 111  *                              V
 112  * 96           Reserved (real-time)
 113  * 95           Kernel mode only
 114  *                              A
 115  *                              +
 116  *                      (16 levels)
 117  *                              +
 118  *                              V
 119  * 80           Kernel mode only
 120  * 79           System high priority
 121  *                              A
 122  *                              +
 123  *                      (16 levels)
 124  *                              +
 125  *                              V
 126  * 64           System high priority
 127  * 63           Elevated priorities
 128  *                              A
 129  *                              +
 130  *                      (12 levels)
 131  *                              +
 132  *                              V
 133  * 52           Elevated priorities
 134  * 51           Elevated priorities (incl. BSD +nice)
 135  *                              A
 136  *                              +
 137  *                      (20 levels)
 138  *                              +
 139  *                              V
 140  * 32           Elevated priorities (incl. BSD +nice)
 141  * 31           Default (default base for threads)
 142  * 30           Lowered priorities (incl. BSD -nice)
 143  *                              A
 144  *                              +
 145  *                      (20 levels)
 146  *                              +
 147  *                              V
 148  * 11           Lowered priorities (incl. BSD -nice)
 149  * 10           Lowered priorities (aged pri's)
 150  *                              A
 151  *                              +
 152  *                      (11 levels)
 153  *                              +
 154  *                              V
 155  * 0            Lowered priorities (aged pri's / idle)
 156  *************************************************************************
 157  */
 158
 159 #define BASEPRI_RTQUEUES        (BASEPRI_REALTIME + 1)                          /* 97 */
 160 #define BASEPRI_REALTIME        (MAXPRI - (NRQS / 4) + 1)                       /* 96 */
 161
 162 #define MAXPRI_STANDARD         (BASEPRI_REALTIME - 1)                          /* 95 */
 163
 164 #define MAXPRI_KERNEL           MAXPRI_STANDARD                                         /* 95 */
 165 #define BASEPRI_PREEMPT         (MAXPRI_KERNEL - 2)                                     /* 93 */
 166 #define BASEPRI_KERNEL          (MINPRI_KERNEL + 1)                                     /* 81 */
 167 #define MINPRI_KERNEL           (MAXPRI_KERNEL - (NRQS / 8) + 1)        /* 80 */
 168
 169 #define MAXPRI_SYSTEM           (MINPRI_KERNEL - 1)                                     /* 79 */
 170 #define MINPRI_SYSTEM           (MAXPRI_SYSTEM - (NRQS / 8) + 1)        /* 64 */
 171
 172 #define MAXPRI_USER                     (MINPRI_SYSTEM - 1)                                     /* 63 */
 173 #define BASEPRI_CONTROL         (BASEPRI_DEFAULT + 17)                          /* 48 */
 174 #define BASEPRI_FOREGROUND      (BASEPRI_DEFAULT + 16)                          /* 47 */
 175 #define BASEPRI_BACKGROUND      (BASEPRI_DEFAULT + 15)                          /* 46 */
 176 #define BASEPRI_DEFAULT         (MAXPRI_USER - (NRQS / 4))                      /* 31 */
 177 #define MINPRI_USER                     MINPRI                                                          /*  0 */
 178
 179 #define MINPRI_STANDARD         MINPRI_USER                                                     /*  0 */
 180
 181 /*
 182  *      Macro to check for invalid priorities.
 183  */
 184 #define invalid_pri(pri) ((pri) < MINPRI || (pri) > MAXPRI)
 185
 186 struct run_queue {
 187         int                                     highq;                          /* highest runnable queue */
 188         int                                     bitmap[NRQBM];          /* run queue bitmap array */
 189         int                                     count;                          /* # of threads total */
 190         int                                     urgency;                        /* level of preemption urgency */
 191         queue_head_t            queues[NRQS];           /* one for each priority */
 192 };
 193
 194 typedef struct run_queue        *run_queue_t;
 195 #define RUN_QUEUE_NULL          ((run_queue_t) 0)
 196
 197 #define first_timeslice(processor)              ((processor)->timeslice > 0)
 198
 199 #define processor_timeslice_setup(processor, thread)                    \
 200 MACRO_BEGIN                                                                                                             \
 201         (processor)->timeslice =                                                                        \
 202                 ((thread)->sched_mode & TH_MODE_TIMESHARE)?                             \
 203                         (processor)->processor_set->timeshare_quanta: 1;        \
 204 MACRO_END
 205
 206 #define thread_quantum_init(thread)                                                     \
 207 MACRO_BEGIN                                                                                                     \
 208         (thread)->current_quantum =                                                     \
 209                 ((thread)->sched_mode & TH_MODE_REALTIME)?                      \
 210                         (thread)->realtime.computation: std_quantum;    \
 211 MACRO_END
 212
 213 /* Invoked at splsched by a thread on itself */
 214 #define csw_needed(thread, processor) (                                                                         \
 215         ((thread)->state & TH_SUSP)                                                                             ||              \
 216         (first_timeslice(processor)?                                                                                    \
 217          ((processor)->runq.highq > (thread)->sched_pri                         ||                      \
 218           (processor)->processor_set->runq.highq > (thread)->sched_pri) :               \
 219          ((processor)->runq.highq >= (thread)->sched_pri                        ||                      \
 220           (processor)->processor_set->runq.highq >= (thread)->sched_pri))       )
 221
 222 /*
 223  *      Scheduler routines.
 224  */
 225
 226 /* Remove thread from its run queue */
 227 extern run_queue_t      run_queue_remove(
 228                                                 thread_t        thread);
 229
 230 /* Periodic computation of load factors */
 231 extern void             compute_mach_factor(void);
 232
 233 /* Handle quantum expiration for an executing thread */
 234 extern void             thread_quantum_expire(
 235                                         timer_call_param_t      processor,
 236                                         timer_call_param_t      thread);
 237
 238 /* Called at splsched by a thread on itself */
 239 extern ast_t    csw_check(
 240                                         thread_t                thread,
 241                                         processor_t             processor);
 242
 243 extern uint32_t std_quantum, min_std_quantum;
 244 extern uint32_t std_quantum_us;
 245
 246 extern uint32_t max_rt_quantum, min_rt_quantum;
 247
 248 /*
 249  *      Shift structures for holding update shifts.  Actual computation
 250  *      is  usage = (usage >> shift1) +/- (usage >> abs(shift2))  where the
 251  *      +/- is determined by the sign of shift 2.
 252  */
 253 struct shift {
 254         int     shift1;
 255         int     shift2;
 256 };
 257
 258 typedef struct shift    *shift_t, shift_data_t;
 259
 260 /*
 261  *      Age usage (1 << SCHED_TICK_SHIFT) times per second.
 262  */
 263
 264 extern unsigned sched_tick;
 265
 266 #define SCHED_TICK_SHIFT        3
 267
 268 #define SCHED_SCALE             128
 269 #define SCHED_SHIFT             7
 270
 271 /*
 272  *      thread_timer_delta macro takes care of both thread timers.
 273  */
 274 #define thread_timer_delta(thread)                                              \
 275 MACRO_BEGIN                                                                                                     \
 276         register uint32_t       delta;                                                          \
 277                                                                                                                         \
 278         delta = 0;                                                                                              \
 279         TIMER_DELTA((thread)->system_timer,                                             \
 280                                         (thread)->system_timer_save, delta);    \
 281         TIMER_DELTA((thread)->user_timer,                                               \
 282                                         (thread)->user_timer_save, delta);              \
 283         (thread)->cpu_delta += delta;                                                   \
 284         (thread)->sched_delta += (delta *                                               \
 285                                         (thread)->processor_set->sched_load);   \
 286 MACRO_END
 287
 288 #if     SIMPLE_CLOCK
 289 /*
 290  *      sched_usec is an exponential average of number of microseconds
 291  *      in a second for clock drift compensation.
 292  */
 293
 294 extern int      sched_usec;
 295 #endif  /* SIMPLE_CLOCK */
 296
 297 #endif  /* _KERN_SCHED_H_ */