osfmk/kern/sched.h

   1 /*
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  13  * terms of an Apple operating system software license agreement.
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  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  */
  58 /*
  59  *      File:   sched.h
  60  *      Author: Avadis Tevanian, Jr.
  61  *      Date:   1985
  62  *
  63  *      Header file for scheduler.
  64  *
  65  */
  66
  67 #ifndef _KERN_SCHED_H_
  68 #define _KERN_SCHED_H_
  69
  70 #include <stat_time.h>
  71
  72 #include <mach/policy.h>
  73 #include <kern/kern_types.h>
  74 #include <kern/queue.h>
  75 #include <kern/lock.h>
  76 #include <kern/macro_help.h>
  77 #include <kern/timer_call.h>
  78 #include <kern/ast.h>
  79
  80 #define NRQS            128                             /* 128 levels per run queue */
  81 #define NRQBM           (NRQS / 32)             /* number of words per bit map */
  82
  83 #define MAXPRI          (NRQS-1)
  84 #define MINPRI          IDLEPRI                 /* lowest legal priority schedulable */
  85 #define IDLEPRI         0                               /* idle thread priority */
  86
  87 /*
  88  *      High-level priority assignments
  89  *
  90  *************************************************************************
  91  * 127          Reserved (real-time)
  92  *                              A
  93  *                              +
  94  *                      (32 levels)
  95  *                              +
  96  *                              V
  97  * 96           Reserved (real-time)
  98  * 95           Kernel mode only
  99  *                              A
 100  *                              +
 101  *                      (16 levels)
 102  *                              +
 103  *                              V
 104  * 80           Kernel mode only
 105  * 79           System high priority
 106  *                              A
 107  *                              +
 108  *                      (16 levels)
 109  *                              +
 110  *                              V
 111  * 64           System high priority
 112  * 63           Elevated priorities
 113  *                              A
 114  *                              +
 115  *                      (12 levels)
 116  *                              +
 117  *                              V
 118  * 52           Elevated priorities
 119  * 51           Elevated priorities (incl. BSD +nice)
 120  *                              A
 121  *                              +
 122  *                      (20 levels)
 123  *                              +
 124  *                              V
 125  * 32           Elevated priorities (incl. BSD +nice)
 126  * 31           Default (default base for threads)
 127  * 30           Lowered priorities (incl. BSD -nice)
 128  *                              A
 129  *                              +
 130  *                      (20 levels)
 131  *                              +
 132  *                              V
 133  * 11           Lowered priorities (incl. BSD -nice)
 134  * 10           Lowered priorities (aged pri's)
 135  *                              A
 136  *                              +
 137  *                      (11 levels)
 138  *                              +
 139  *                              V
 140  * 0            Lowered priorities (aged pri's / idle)
 141  *************************************************************************
 142  */
 143
 144 #define BASEPRI_RTQUEUES        (BASEPRI_REALTIME + 1)                          /* 97 */
 145 #define BASEPRI_REALTIME        (MAXPRI - (NRQS / 4) + 1)                       /* 96 */
 146
 147 #define MAXPRI_KERNEL           (BASEPRI_REALTIME - 1)                          /* 95 */
 148 #define BASEPRI_PREEMPT         (MAXPRI_KERNEL - 2)                                     /* 93 */
 149 #define BASEPRI_KERNEL          (MINPRI_KERNEL + 1)                                     /* 81 */
 150 #define MINPRI_KERNEL           (MAXPRI_KERNEL - (NRQS / 8) + 1)        /* 80 */
 151
 152 #define MAXPRI_RESERVED         (MINPRI_KERNEL - 1)                                     /* 79 */
 153 #define MINPRI_RESERVED         (MAXPRI_RESERVED - (NRQS / 8) + 1)      /* 64 */
 154
 155 #define MAXPRI_USER                     (MINPRI_RESERVED - 1)                           /* 63 */
 156 #define BASEPRI_CONTROL         (BASEPRI_DEFAULT + 17)                          /* 48 */
 157 #define BASEPRI_FOREGROUND      (BASEPRI_DEFAULT + 16)                          /* 47 */
 158 #define BASEPRI_BACKGROUND      (BASEPRI_DEFAULT + 15)                          /* 46 */
 159 #define BASEPRI_DEFAULT         (MAXPRI_USER - (NRQS / 4))                      /* 31 */
 160 #define MAXPRI_THROTTLE         (MINPRI + 4)                                            /*  4 */
 161 #define MINPRI_USER                     MINPRI                                                          /*  0 */
 162
 163 #ifdef CONFIG_EMBEDDED
 164 #define DEPRESSPRI      MAXPRI_THROTTLE
 165 #else
 166 #define DEPRESSPRI      MINPRI                  /* depress priority */
 167 #endif
 168
 169 /* Type used for thread->sched_mode and saved_mode */
 170 typedef enum {
 171         TH_MODE_NONE = 0,                                       /* unassigned, usually for saved_mode only */
 172         TH_MODE_REALTIME,                                       /* time constraints supplied */
 173         TH_MODE_FIXED,                                          /* use fixed priorities, no decay */
 174         TH_MODE_TIMESHARE,                                      /* use timesharing algorithm */
 175         TH_MODE_FAIRSHARE                                       /* use fair-share scheduling */
 176 } sched_mode_t;
 177
 178 /*
 179  *      Macro to check for invalid priorities.
 180  */
 181 #define invalid_pri(pri) ((pri) < MINPRI || (pri) > MAXPRI)
 182
 183 struct runq_stats {
 184         uint64_t                                count_sum;
 185         uint64_t                                last_change_timestamp;
 186 };
 187
 188 #if defined(CONFIG_SCHED_TRADITIONAL) || defined(CONFIG_SCHED_PROTO) || defined(CONFIG_SCHED_FIXEDPRIORITY)
 189
 190 struct run_queue {
 191         int                                     highq;                          /* highest runnable queue */
 192         int                                     bitmap[NRQBM];          /* run queue bitmap array */
 193         int                                     count;                          /* # of threads total */
 194         int                                     urgency;                        /* level of preemption urgency */
 195         queue_head_t            queues[NRQS];           /* one for each priority */
 196
 197         struct runq_stats       runq_stats;
 198 };
 199
 200 #endif /* defined(CONFIG_SCHED_TRADITIONAL) || defined(CONFIG_SCHED_PROTO) || defined(CONFIG_SCHED_FIXEDPRIORITY) */
 201
 202 struct rt_queue {
 203         int                                     count;                          /* # of threads total */
 204         queue_head_t            queue;                          /* all runnable RT threads */
 205
 206         struct runq_stats       runq_stats;
 207 };
 208
 209 #if defined(CONFIG_SCHED_TRADITIONAL) || defined(CONFIG_SCHED_PROTO) || defined(CONFIG_SCHED_FIXEDPRIORITY)
 210 struct fairshare_queue {
 211         int                                     count;                          /* # of threads total */
 212         queue_head_t            queue;                          /* all runnable threads demoted to fairshare scheduling */
 213
 214         struct runq_stats       runq_stats;
 215 };
 216 #endif
 217
 218 #if defined(CONFIG_SCHED_GRRR_CORE)
 219
 220 /*
 221  * We map standard Mach priorities to an abstract scale that more properly
 222  * indicates how we want processor time allocated under contention.
 223  */
 224 typedef uint8_t grrr_proportional_priority_t;
 225 typedef uint8_t grrr_group_index_t;
 226
 227 #define NUM_GRRR_PROPORTIONAL_PRIORITIES        256
 228 #define MAX_GRRR_PROPORTIONAL_PRIORITY ((grrr_proportional_priority_t)255)
 229
 230 #if 0
 231 #define NUM_GRRR_GROUPS 8                                       /* log(256) */
 232 #endif
 233
 234 #define NUM_GRRR_GROUPS 64                                      /* 256/4 */
 235
 236 struct grrr_group {
 237         queue_chain_t                   priority_order;                         /* next greatest weight group */
 238         grrr_proportional_priority_t            minpriority;
 239         grrr_group_index_t              index;
 240
 241         queue_head_t                    clients;
 242         int                                             count;
 243         uint32_t                                weight;
 244 #if 0
 245         uint32_t                                deferred_removal_weight;
 246 #endif
 247         uint32_t                                work;
 248         thread_t                                current_client;
 249 };
 250
 251 struct grrr_run_queue {
 252         int                                     count;
 253         uint32_t                        last_rescale_tick;
 254         struct grrr_group       groups[NUM_GRRR_GROUPS];
 255         queue_head_t            sorted_group_list;
 256         uint32_t                        weight;
 257         grrr_group_t            current_group;
 258
 259         struct runq_stats   runq_stats;
 260 };
 261
 262 #endif /* defined(CONFIG_SCHED_GRRR_CORE) */
 263
 264 #define first_timeslice(processor)              ((processor)->timeslice > 0)
 265
 266 extern struct rt_queue          rt_runq;
 267
 268 /*
 269  *      Scheduler routines.
 270  */
 271
 272 /* Handle quantum expiration for an executing thread */
 273 extern void             thread_quantum_expire(
 274                                         timer_call_param_t      processor,
 275                                         timer_call_param_t      thread);
 276
 277 /* Context switch check for current processor */
 278 extern ast_t    csw_check(processor_t           processor);
 279
 280 #if defined(CONFIG_SCHED_TRADITIONAL)
 281 extern uint32_t std_quantum, min_std_quantum;
 282 extern uint32_t std_quantum_us;
 283 #endif
 284
 285 extern uint32_t thread_depress_time;
 286 extern uint32_t default_timeshare_computation;
 287 extern uint32_t default_timeshare_constraint;
 288
 289 extern uint32_t max_rt_quantum, min_rt_quantum;
 290
 291 extern uint32_t sched_cswtime;
 292
 293 #if defined(CONFIG_SCHED_TRADITIONAL)
 294
 295 /*
 296  *      Age usage (1 << SCHED_TICK_SHIFT) times per second.
 297  */
 298 #define SCHED_TICK_SHIFT        3
 299
 300 extern unsigned         sched_tick;
 301 extern uint32_t         sched_tick_interval;
 302
 303 #endif /* CONFIG_SCHED_TRADITIONAL */
 304
 305 extern uint64_t         sched_one_second_interval;
 306
 307 /* Periodic computation of various averages */
 308 extern void             compute_averages(void);
 309
 310 extern void             compute_averunnable(
 311                                         void                    *nrun);
 312
 313 extern void             compute_stack_target(
 314                                         void                    *arg);
 315
 316 extern void             compute_memory_pressure(
 317                                         void                    *arg);
 318
 319 extern void             compute_zone_gc_throttle(
 320                                         void                    *arg);
 321
 322 extern void             compute_pmap_gc_throttle(
 323                                         void                    *arg);
 324
 325 /*
 326  *      Conversion factor from usage
 327  *      to priority.
 328  */
 329 #if defined(CONFIG_SCHED_TRADITIONAL)
 330 extern uint32_t         sched_pri_shift;
 331 extern uint32_t         sched_fixed_shift;
 332 extern int8_t           sched_load_shifts[NRQS];
 333 #endif
 334
 335 extern int32_t          sched_poll_yield_shift;
 336 extern uint64_t         sched_safe_duration;
 337
 338 extern uint32_t         sched_run_count, sched_share_count;
 339 extern uint32_t         sched_load_average, sched_mach_factor;
 340
 341 extern uint32_t         avenrun[3], mach_factor[3];
 342
 343 extern uint64_t         max_unsafe_computation;
 344 extern uint64_t         max_poll_computation;
 345
 346 #define sched_run_incr()                        \
 347 MACRO_BEGIN                                     \
 348          hw_atomic_add(&sched_run_count, 1);    \
 349 MACRO_END
 350
 351 #define sched_run_decr()                        \
 352 MACRO_BEGIN                                     \
 353         hw_atomic_sub(&sched_run_count, 1);     \
 354 MACRO_END
 355
 356 #define sched_share_incr()                      \
 357 MACRO_BEGIN                                                                                     \
 358         (void)hw_atomic_add(&sched_share_count, 1);             \
 359 MACRO_END
 360
 361 #define sched_share_decr()                      \
 362 MACRO_BEGIN                                                                                     \
 363         (void)hw_atomic_sub(&sched_share_count, 1);             \
 364 MACRO_END
 365
 366 /*
 367  *      thread_timer_delta macro takes care of both thread timers.
 368  */
 369 #define thread_timer_delta(thread, delta)                                       \
 370 MACRO_BEGIN                                                                                                     \
 371         (delta) = (typeof(delta))timer_delta(&(thread)->system_timer,                   \
 372                                                         &(thread)->system_timer_save);  \
 373         (delta) += (typeof(delta))timer_delta(&(thread)->user_timer,                    \
 374                                                         &(thread)->user_timer_save);    \
 375 MACRO_END
 376
 377 #endif  /* _KERN_SCHED_H_ */