osfmk/kern/sched.h

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