osfmk/kern/sched.h

   1 /*
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  10  * may not be used to create, or enable the creation or redistribution of,
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  13  * terms of an Apple operating system software license agreement.
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  17  *
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  23  * Please see the License for the specific language governing rights and
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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 <mach/policy.h>
  71 #include <kern/kern_types.h>
  72 #include <kern/smp.h>
  73 #include <kern/queue.h>
  74 #include <kern/macro_help.h>
  75 #include <kern/timer_call.h>
  76 #include <kern/ast.h>
  77 #include <kern/kalloc.h>
  78 #include <kern/bits.h>
  79
  80 #define NRQS            128                             /* 128 levels per run queue */
  81
  82 #define MAXPRI          (NRQS-1)
  83 #define MINPRI          0                               /* lowest legal priority schedulable */
  84 #define IDLEPRI         MINPRI                          /* idle thread priority */
  85 #define NOPRI           -1
  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_HIGH    (BASEPRI_PREEMPT + 1)                           /* 93 */
 149 #define BASEPRI_PREEMPT         (MAXPRI_KERNEL - 3)                             /* 92 */
 150 #define BASEPRI_VM              (BASEPRI_PREEMPT - 1)                           /* 91 */
 151
 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 BASEPRI_GRAPHICS        (MAXPRI_RESERVED - 3)                           /* 76 */
 157 #define MINPRI_RESERVED         (MAXPRI_RESERVED - (NRQS / 8) + 1)              /* 64 */
 158
 159 #define MAXPRI_USER             (MINPRI_RESERVED - 1)                           /* 63 */
 160 #define BASEPRI_CONTROL         (BASEPRI_DEFAULT + 17)                          /* 48 */
 161 #define BASEPRI_FOREGROUND      (BASEPRI_DEFAULT + 16)                          /* 47 */
 162 #define BASEPRI_BACKGROUND      (BASEPRI_DEFAULT + 15)                          /* 46 */
 163 #define BASEPRI_USER_INITIATED  (BASEPRI_DEFAULT +  6)                          /* 37 */
 164 #define BASEPRI_DEFAULT         (MAXPRI_USER - (NRQS / 4))                      /* 31 */
 165 #define MAXPRI_SUPPRESSED       (BASEPRI_DEFAULT - 3)                           /* 28 */
 166 #define BASEPRI_UTILITY         (BASEPRI_DEFAULT - 11)                          /* 20 */
 167 #define MAXPRI_THROTTLE         (MINPRI + 4)                                    /*  4 */
 168 #define MINPRI_USER             MINPRI                                          /*  0 */
 169
 170 #define DEPRESSPRI              MINPRI                  /* depress priority */
 171 #define MAXPRI_PROMOTE          (MAXPRI_KERNEL)         /* ceiling for mutex promotion */
 172
 173 /* Type used for thread->sched_mode and saved_mode */
 174 typedef enum {
 175         TH_MODE_NONE = 0,                                       /* unassigned, usually for saved_mode only */
 176         TH_MODE_REALTIME,                                       /* time constraints supplied */
 177         TH_MODE_FIXED,                                          /* use fixed priorities, no decay */
 178         TH_MODE_TIMESHARE,                                      /* use timesharing algorithm */
 179 } sched_mode_t;
 180
 181 /* Buckets used for load calculation */
 182 typedef enum {
 183         TH_BUCKET_RUN = 0,      /* All runnable threads */
 184         TH_BUCKET_FIXPRI,       /* Fixed-priority */
 185         TH_BUCKET_SHARE_FG,     /* Timeshare thread above BASEPRI_UTILITY */
 186         TH_BUCKET_SHARE_UT,     /* Timeshare thread between BASEPRI_UTILITY and MAXPRI_THROTTLE */
 187         TH_BUCKET_SHARE_BG,     /* Timeshare thread between MAXPRI_THROTTLE and MINPRI */
 188         TH_BUCKET_MAX,
 189 } sched_bucket_t;
 190
 191 /*
 192  *      Macro to check for invalid priorities.
 193  */
 194 #define invalid_pri(pri) ((pri) < MINPRI || (pri) > MAXPRI)
 195
 196 struct runq_stats {
 197         uint64_t                                count_sum;
 198         uint64_t                                last_change_timestamp;
 199 };
 200
 201 #if defined(CONFIG_SCHED_TIMESHARE_CORE) || defined(CONFIG_SCHED_PROTO)
 202
 203 struct run_queue {
 204         int                                     highq;                          /* highest runnable queue */
 205         bitmap_t                                bitmap[BITMAP_LEN(NRQS)];       /* run queue bitmap array */
 206         int                                     count;                          /* # of threads total */
 207         int                                     urgency;                        /* level of preemption urgency */
 208         queue_head_t            queues[NRQS];           /* one for each priority */
 209
 210         struct runq_stats       runq_stats;
 211 };
 212
 213 inline static void
 214 rq_bitmap_set(bitmap_t *map, u_int n)
 215 {
 216         assert(n < NRQS);
 217         bitmap_set(map, n);
 218 }
 219
 220 inline static void
 221 rq_bitmap_clear(bitmap_t *map, u_int n)
 222 {
 223         assert(n < NRQS);
 224         bitmap_clear(map, n);
 225 }
 226
 227 #endif /* defined(CONFIG_SCHED_TIMESHARE_CORE) || defined(CONFIG_SCHED_PROTO) */
 228
 229 struct rt_queue {
 230         _Atomic int             count;                          /* # of threads total */
 231         queue_head_t            queue;                          /* all runnable RT threads */
 232 #if __SMP__
 233         decl_simple_lock_data(,rt_lock)
 234 #endif
 235         struct runq_stats       runq_stats;
 236 };
 237 typedef struct rt_queue *rt_queue_t;
 238
 239 #if defined(CONFIG_SCHED_GRRR_CORE)
 240
 241 /*
 242  * We map standard Mach priorities to an abstract scale that more properly
 243  * indicates how we want processor time allocated under contention.
 244  */
 245 typedef uint8_t grrr_proportional_priority_t;
 246 typedef uint8_t grrr_group_index_t;
 247
 248 #define NUM_GRRR_PROPORTIONAL_PRIORITIES        256
 249 #define MAX_GRRR_PROPORTIONAL_PRIORITY ((grrr_proportional_priority_t)255)
 250
 251 #if 0
 252 #define NUM_GRRR_GROUPS 8                                       /* log(256) */
 253 #endif
 254
 255 #define NUM_GRRR_GROUPS 64                                      /* 256/4 */
 256
 257 struct grrr_group {
 258         queue_chain_t                   priority_order;                         /* next greatest weight group */
 259         grrr_proportional_priority_t            minpriority;
 260         grrr_group_index_t              index;
 261
 262         queue_head_t                    clients;
 263         int                                             count;
 264         uint32_t                                weight;
 265 #if 0
 266         uint32_t                                deferred_removal_weight;
 267 #endif
 268         uint32_t                                work;
 269         thread_t                                current_client;
 270 };
 271
 272 struct grrr_run_queue {
 273         int                                     count;
 274         uint32_t                        last_rescale_tick;
 275         struct grrr_group       groups[NUM_GRRR_GROUPS];
 276         queue_head_t            sorted_group_list;
 277         uint32_t                        weight;
 278         grrr_group_t            current_group;
 279
 280         struct runq_stats   runq_stats;
 281 };
 282
 283 #endif /* defined(CONFIG_SCHED_GRRR_CORE) */
 284
 285 extern int rt_runq_count(processor_set_t);
 286 extern void rt_runq_count_incr(processor_set_t);
 287 extern void rt_runq_count_decr(processor_set_t);
 288
 289 #if defined(CONFIG_SCHED_MULTIQ)
 290 sched_group_t   sched_group_create(void);
 291 void            sched_group_destroy(sched_group_t sched_group);
 292 #endif /* defined(CONFIG_SCHED_MULTIQ) */
 293
 294
 295
 296 /*
 297  *      Scheduler routines.
 298  */
 299
 300 /* Handle quantum expiration for an executing thread */
 301 extern void             thread_quantum_expire(
 302                                         timer_call_param_t      processor,
 303                                         timer_call_param_t      thread);
 304
 305 /* Context switch check for current processor */
 306 extern ast_t    csw_check(processor_t           processor,
 307                                                 ast_t                   check_reason);
 308
 309 #if defined(CONFIG_SCHED_TIMESHARE_CORE)
 310 extern uint32_t std_quantum, min_std_quantum;
 311 extern uint32_t std_quantum_us;
 312 #endif /* CONFIG_SCHED_TIMESHARE_CORE */
 313
 314 extern uint32_t thread_depress_time;
 315 extern uint32_t default_timeshare_computation;
 316 extern uint32_t default_timeshare_constraint;
 317
 318 extern uint32_t max_rt_quantum, min_rt_quantum;
 319
 320 extern int default_preemption_rate;
 321 extern int default_bg_preemption_rate;
 322
 323 #if defined(CONFIG_SCHED_TIMESHARE_CORE)
 324
 325 /*
 326  *      Age usage  at approximately (1 << SCHED_TICK_SHIFT) times per second
 327  *      Aging may be deferred during periods where all processors are idle
 328  *      and cumulatively applied during periods of activity.
 329  */
 330 #define SCHED_TICK_SHIFT        3
 331 #define SCHED_TICK_MAX_DELTA    (8)
 332
 333 extern unsigned         sched_tick;
 334 extern uint32_t         sched_tick_interval;
 335
 336 #endif /* CONFIG_SCHED_TIMESHARE_CORE */
 337
 338 extern uint64_t         sched_one_second_interval;
 339
 340 /* Periodic computation of various averages */
 341 extern void             compute_averages(uint64_t);
 342
 343 extern void             compute_averunnable(
 344                                         void                    *nrun);
 345
 346 extern void             compute_stack_target(
 347                                         void                    *arg);
 348
 349 extern void             compute_memory_pressure(
 350                                         void                    *arg);
 351
 352 extern void             compute_pageout_gc_throttle(
 353                                         void                    *arg);
 354
 355 extern void             compute_pmap_gc_throttle(
 356                                         void                    *arg);
 357
 358 /*
 359  *      Conversion factor from usage
 360  *      to priority.
 361  */
 362 #if defined(CONFIG_SCHED_TIMESHARE_CORE)
 363
 364 #define MAX_LOAD (NRQS - 1)
 365 extern uint32_t         sched_pri_shifts[TH_BUCKET_MAX];
 366 extern uint32_t         sched_fixed_shift;
 367 extern int8_t           sched_load_shifts[NRQS];
 368 extern uint32_t         sched_decay_usage_age_factor;
 369 void sched_timeshare_consider_maintenance(uint64_t ctime);
 370 #endif /* CONFIG_SCHED_TIMESHARE_CORE */
 371
 372 void sched_consider_recommended_cores(uint64_t ctime, thread_t thread);
 373
 374 extern int32_t          sched_poll_yield_shift;
 375 extern uint64_t         sched_safe_duration;
 376
 377 extern uint32_t         sched_load_average, sched_mach_factor;
 378
 379 extern uint32_t         avenrun[3], mach_factor[3];
 380
 381 extern uint64_t         max_unsafe_computation;
 382 extern uint64_t         max_poll_computation;
 383
 384 extern volatile uint32_t sched_run_buckets[TH_BUCKET_MAX];
 385
 386 extern uint32_t sched_run_incr(thread_t thread);
 387 extern uint32_t sched_run_decr(thread_t thread);
 388
 389 /*
 390  *      thread_timer_delta macro takes care of both thread timers.
 391  */
 392 #define thread_timer_delta(thread, delta)                                       \
 393 MACRO_BEGIN                                                                                                     \
 394         (delta) = (typeof(delta))timer_delta(&(thread)->system_timer,                   \
 395                                                         &(thread)->system_timer_save);  \
 396         (delta) += (typeof(delta))timer_delta(&(thread)->user_timer,                    \
 397                                                         &(thread)->user_timer_save);    \
 398 MACRO_END
 399
 400 #endif  /* _KERN_SCHED_H_ */