osfmk/kern/sched.h

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * @OSF_COPYRIGHT@
  25  */
  26 /*
  27  * Mach Operating System
  28  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  29  * All Rights Reserved.
  30  *
  31  * Permission to use, copy, modify and distribute this software and its
  32  * documentation is hereby granted, provided that both the copyright
  33  * notice and this permission notice appear in all copies of the
  34  * software, derivative works or modified versions, and any portions
  35  * thereof, and that both notices appear in supporting documentation.
  36  *
  37  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  38  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  39  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  40  *
  41  * Carnegie Mellon requests users of this software to return to
  42  *
  43  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  44  *  School of Computer Science
  45  *  Carnegie Mellon University
  46  *  Pittsburgh PA 15213-3890
  47  *
  48  * any improvements or extensions that they make and grant Carnegie Mellon
  49  * the rights to redistribute these changes.
  50  */
  51 /*
  52  */
  53 /*
  54  *      File:   sched.h
  55  *      Author: Avadis Tevanian, Jr.
  56  *      Date:   1985
  57  *
  58  *      Header file for scheduler.
  59  *
  60  */
  61
  62 #ifndef _KERN_SCHED_H_
  63 #define _KERN_SCHED_H_
  64
  65 #include <stat_time.h>
  66
  67 #include <mach/policy.h>
  68 #include <kern/kern_types.h>
  69 #include <kern/queue.h>
  70 #include <kern/lock.h>
  71 #include <kern/macro_help.h>
  72 #include <kern/timer_call.h>
  73 #include <kern/ast.h>
  74
  75 #define NRQS            128                             /* 128 levels per run queue */
  76 #define NRQBM           (NRQS / 32)             /* number of words per bit map */
  77
  78 #define MAXPRI          (NRQS-1)
  79 #define MINPRI          IDLEPRI                 /* lowest legal priority schedulable */
  80 #define IDLEPRI         0                               /* idle thread priority */
  81 #define DEPRESSPRI      MINPRI                  /* depress priority */
  82
  83 /*
  84  *      High-level priority assignments
  85  *
  86  *************************************************************************
  87  * 127          Reserved (real-time)
  88  *                              A
  89  *                              +
  90  *                      (32 levels)
  91  *                              +
  92  *                              V
  93  * 96           Reserved (real-time)
  94  * 95           Kernel mode only
  95  *                              A
  96  *                              +
  97  *                      (16 levels)
  98  *                              +
  99  *                              V
 100  * 80           Kernel mode only
 101  * 79           System high priority
 102  *                              A
 103  *                              +
 104  *                      (16 levels)
 105  *                              +
 106  *                              V
 107  * 64           System high priority
 108  * 63           Elevated priorities
 109  *                              A
 110  *                              +
 111  *                      (12 levels)
 112  *                              +
 113  *                              V
 114  * 52           Elevated priorities
 115  * 51           Elevated priorities (incl. BSD +nice)
 116  *                              A
 117  *                              +
 118  *                      (20 levels)
 119  *                              +
 120  *                              V
 121  * 32           Elevated priorities (incl. BSD +nice)
 122  * 31           Default (default base for threads)
 123  * 30           Lowered priorities (incl. BSD -nice)
 124  *                              A
 125  *                              +
 126  *                      (20 levels)
 127  *                              +
 128  *                              V
 129  * 11           Lowered priorities (incl. BSD -nice)
 130  * 10           Lowered priorities (aged pri's)
 131  *                              A
 132  *                              +
 133  *                      (11 levels)
 134  *                              +
 135  *                              V
 136  * 0            Lowered priorities (aged pri's / idle)
 137  *************************************************************************
 138  */
 139
 140 #define BASEPRI_RTQUEUES        (BASEPRI_REALTIME + 1)                          /* 97 */
 141 #define BASEPRI_REALTIME        (MAXPRI - (NRQS / 4) + 1)                       /* 96 */
 142
 143 #define MAXPRI_KERNEL           (BASEPRI_REALTIME - 1)                          /* 95 */
 144 #define BASEPRI_PREEMPT         (MAXPRI_KERNEL - 2)                                     /* 93 */
 145 #define BASEPRI_KERNEL          (MINPRI_KERNEL + 1)                                     /* 81 */
 146 #define MINPRI_KERNEL           (MAXPRI_KERNEL - (NRQS / 8) + 1)        /* 80 */
 147
 148 #define MAXPRI_RESERVED         (MINPRI_KERNEL - 1)                                     /* 79 */
 149 #define MINPRI_RESERVED         (MAXPRI_RESERVED - (NRQS / 8) + 1)      /* 64 */
 150
 151 #define MAXPRI_USER                     (MINPRI_RESERVED - 1)                           /* 63 */
 152 #define BASEPRI_CONTROL         (BASEPRI_DEFAULT + 17)                          /* 48 */
 153 #define BASEPRI_FOREGROUND      (BASEPRI_DEFAULT + 16)                          /* 47 */
 154 #define BASEPRI_BACKGROUND      (BASEPRI_DEFAULT + 15)                          /* 46 */
 155 #define BASEPRI_DEFAULT         (MAXPRI_USER - (NRQS / 4))                      /* 31 */
 156 #define MINPRI_USER                     MINPRI                                                          /*  0 */
 157
 158 /*
 159  *      Macro to check for invalid priorities.
 160  */
 161 #define invalid_pri(pri) ((pri) < MINPRI || (pri) > MAXPRI)
 162
 163 struct run_queue {
 164         int                                     highq;                          /* highest runnable queue */
 165         int                                     bitmap[NRQBM];          /* run queue bitmap array */
 166         int                                     count;                          /* # of threads total */
 167         int                                     urgency;                        /* level of preemption urgency */
 168         queue_head_t            queues[NRQS];           /* one for each priority */
 169 };
 170
 171 typedef struct run_queue        *run_queue_t;
 172 #define RUN_QUEUE_NULL          ((run_queue_t) 0)
 173
 174 #define first_timeslice(processor)              ((processor)->timeslice > 0)
 175
 176 #define processor_timeslice_setup(processor, thread)                    \
 177 MACRO_BEGIN                                                                                                             \
 178         (processor)->timeslice =                                                                        \
 179                 ((thread)->sched_mode & TH_MODE_TIMESHARE)?                             \
 180                         (processor)->processor_set->timeshare_quanta: 1;        \
 181 MACRO_END
 182
 183 #define thread_quantum_init(thread)                                                     \
 184 MACRO_BEGIN                                                                                                     \
 185         (thread)->current_quantum =                                                     \
 186                 ((thread)->sched_mode & TH_MODE_REALTIME)?                      \
 187                         (thread)->realtime.computation: std_quantum;    \
 188 MACRO_END
 189
 190 /* Invoked at splsched by a thread on itself */
 191 #define csw_needed(thread, processor) (                                                                         \
 192         ((thread)->state & TH_SUSP)                                                                             ||              \
 193         (first_timeslice(processor)?                                                                                    \
 194          ((processor)->runq.highq > (thread)->sched_pri                         ||                      \
 195           (processor)->processor_set->runq.highq > (thread)->sched_pri) :               \
 196          ((processor)->runq.highq >= (thread)->sched_pri                        ||                      \
 197           (processor)->processor_set->runq.highq >= (thread)->sched_pri))       )
 198
 199 /*
 200  *      Scheduler routines.
 201  */
 202
 203 /* Remove thread from its run queue */
 204 extern run_queue_t      run_queue_remove(
 205                                                 thread_t        thread);
 206
 207 /* Handle quantum expiration for an executing thread */
 208 extern void             thread_quantum_expire(
 209                                         timer_call_param_t      processor,
 210                                         timer_call_param_t      thread);
 211
 212 /* Called at splsched by a thread on itself */
 213 extern ast_t    csw_check(
 214                                         thread_t                thread,
 215                                         processor_t             processor);
 216
 217 extern uint32_t std_quantum, min_std_quantum;
 218 extern uint32_t std_quantum_us;
 219
 220 extern uint32_t max_rt_quantum, min_rt_quantum;
 221
 222 extern uint32_t sched_cswtime;
 223
 224 /*
 225  *      Age usage (1 << SCHED_TICK_SHIFT) times per second.
 226  */
 227 #define SCHED_TICK_SHIFT        3
 228
 229 extern unsigned         sched_tick;
 230 extern uint32_t         sched_tick_interval;
 231
 232 /* Periodic computation of various averages */
 233 extern void             compute_averages(void);
 234
 235 extern void             compute_averunnable(
 236                                         void                    *nrun);
 237
 238 extern void             compute_stack_target(
 239                                         void                    *arg);
 240
 241 /*
 242  *      Conversion factor from usage
 243  *      to priority.
 244  */
 245 extern uint32_t         sched_pri_shift;
 246
 247 /*
 248  *      Scaling factor for usage
 249  *      based on load.
 250  */
 251 extern int8_t           sched_load_shifts[NRQS];
 252
 253 extern int32_t          sched_poll_yield_shift;
 254 extern uint32_t         sched_safe_duration;
 255
 256 extern uint64_t         max_unsafe_computation;
 257 extern uint64_t         max_poll_computation;
 258
 259 extern uint32_t         avenrun[3], mach_factor[3];
 260
 261 /*
 262  *      thread_timer_delta macro takes care of both thread timers.
 263  */
 264 #define thread_timer_delta(thread, delta)                                       \
 265 MACRO_BEGIN                                                                                                     \
 266         (delta) = timer_delta(&(thread)->system_timer,                  \
 267                                                         &(thread)->system_timer_save);  \
 268         (delta) += timer_delta(&(thread)->user_timer,                   \
 269                                                         &(thread)->user_timer_save);    \
 270 MACRO_END
 271
 272 #endif  /* _KERN_SCHED_H_ */