1 /*
2 * Copyright (c) 2000-2019 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_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. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
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 [email protected]
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/circle_queue.h>
74 #include <kern/macro_help.h>
75 #include <kern/timer_call.h>
76 #include <kern/ast.h>
77 #include <kern/bits.h>
78
79 #define NRQS_MAX (128) /* maximum number of priority levels */
80
81 #define MAXPRI (NRQS_MAX-1)
82 #define MINPRI 0 /* lowest legal priority schedulable */
83 #define IDLEPRI MINPRI /* idle thread priority */
84 #define NOPRI -1
85
86 /*
87 * High-level priority assignments
88 *
89 *************************************************************************
90 * 127 Reserved (real-time)
91 * A
92 * +
93 * (32 levels)
94 * +
95 * V
96 * 96 Reserved (real-time)
97 * 95 Kernel mode only
98 * A
99 * +
100 * (16 levels)
101 * +
102 * V
103 * 80 Kernel mode only
104 * 79 System high priority
105 * A
106 * +
107 * (16 levels)
108 * +
109 * V
110 * 64 System high priority
111 * 63 Elevated priorities
112 * A
113 * +
114 * (12 levels)
115 * +
116 * V
117 * 52 Elevated priorities
118 * 51 Elevated priorities (incl. BSD +nice)
119 * A
120 * +
121 * (20 levels)
122 * +
123 * V
124 * 32 Elevated priorities (incl. BSD +nice)
125 * 31 Default (default base for threads)
126 * 30 Lowered priorities (incl. BSD -nice)
127 * A
128 * +
129 * (20 levels)
130 * +
131 * V
132 * 11 Lowered priorities (incl. BSD -nice)
133 * 10 Lowered priorities (aged pri's)
134 * A
135 * +
136 * (11 levels)
137 * +
138 * V
139 * 0 Lowered priorities (aged pri's / idle)
140 *************************************************************************
141 */
142
143 #define BASEPRI_RTQUEUES (BASEPRI_REALTIME + 1) /* 97 */
144 #define BASEPRI_REALTIME (MAXPRI - (NRQS_MAX / 4) + 1) /* 96 */
145
146 #define MAXPRI_KERNEL (BASEPRI_REALTIME - 1) /* 95 */
147 #define BASEPRI_PREEMPT_HIGH (BASEPRI_PREEMPT + 1) /* 93 */
148 #define BASEPRI_PREEMPT (MAXPRI_KERNEL - 3) /* 92 */
149 #define BASEPRI_VM (BASEPRI_PREEMPT - 1) /* 91 */
150
151 #define BASEPRI_KERNEL (MINPRI_KERNEL + 1) /* 81 */
152 #define MINPRI_KERNEL (MAXPRI_KERNEL - (NRQS_MAX / 8) + 1) /* 80 */
153
154 #define MAXPRI_RESERVED (MINPRI_KERNEL - 1) /* 79 */
155 #define BASEPRI_GRAPHICS (MAXPRI_RESERVED - 3) /* 76 */
156 #define MINPRI_RESERVED (MAXPRI_RESERVED - (NRQS_MAX / 8) + 1) /* 64 */
157
158 #define MAXPRI_USER (MINPRI_RESERVED - 1) /* 63 */
159 #define BASEPRI_CONTROL (BASEPRI_DEFAULT + 17) /* 48 */
160 #define BASEPRI_FOREGROUND (BASEPRI_DEFAULT + 16) /* 47 */
161 #define BASEPRI_BACKGROUND (BASEPRI_DEFAULT + 15) /* 46 */
162 #define BASEPRI_USER_INITIATED (BASEPRI_DEFAULT + 6) /* 37 */
163 #define BASEPRI_DEFAULT (MAXPRI_USER - (NRQS_MAX / 4)) /* 31 */
164 #define MAXPRI_SUPPRESSED (BASEPRI_DEFAULT - 3) /* 28 */
165 #define BASEPRI_UTILITY (BASEPRI_DEFAULT - 11) /* 20 */
166 #define MAXPRI_THROTTLE (MINPRI + 4) /* 4 */
167 #define MINPRI_USER MINPRI /* 0 */
168
169 #define DEPRESSPRI (MINPRI) /* depress priority */
170
171 #define MAXPRI_PROMOTE (MAXPRI_KERNEL) /* ceiling for mutex promotion */
172 #define MINPRI_RWLOCK (BASEPRI_BACKGROUND) /* floor when holding rwlock count */
173 #define MINPRI_EXEC (BASEPRI_DEFAULT) /* floor when in exec state */
174 #define MINPRI_WAITQ (BASEPRI_DEFAULT) /* floor when in waitq handover state */
175 #define MINPRI_FLOOR (BASEPRI_BACKGROUND) /* floor when boost requested */
176
177 #define NRQS (BASEPRI_REALTIME) /* Non-realtime levels for runqs */
178 #define NRTQS (MAXPRI - BASEPRI_REALTIME) /* Realtime levels for runqs */
179
180 /* Ensure that NRQS is large enough to represent all non-realtime threads; even promoted ones */
181 _Static_assert((NRQS == (MAXPRI_PROMOTE + 1)), "Runqueues are too small to hold all non-realtime threads");
182
183 /* Type used for thread->sched_mode and saved_mode */
184 typedef enum {
185 TH_MODE_NONE = 0, /* unassigned, usually for saved_mode only */
186 TH_MODE_REALTIME, /* time constraints supplied */
187 TH_MODE_FIXED, /* use fixed priorities, no decay */
188 TH_MODE_TIMESHARE, /* use timesharing algorithm */
189 } sched_mode_t;
190
191 /*
192 * Since the clutch scheduler organizes threads based on the thread group
193 * and the scheduling bucket, its important to not mix threads from multiple
194 * priority bands into the same bucket. To achieve that, in the clutch bucket
195 * world, there is a scheduling bucket per QoS effectively.
196 */
197
198 /* Buckets used for load calculation */
199 typedef enum {
200 TH_BUCKET_FIXPRI = 0, /* Fixed-priority */
201 TH_BUCKET_SHARE_FG, /* Timeshare thread above BASEPRI_DEFAULT */
202 #if CONFIG_SCHED_CLUTCH
203 TH_BUCKET_SHARE_IN, /* Timeshare thread between BASEPRI_USER_INITIATED and BASEPRI_DEFAULT */
204 #endif /* CONFIG_SCHED_CLUTCH */
205 TH_BUCKET_SHARE_DF, /* Timeshare thread between BASEPRI_DEFAULT and BASEPRI_UTILITY */
206 TH_BUCKET_SHARE_UT, /* Timeshare thread between BASEPRI_UTILITY and MAXPRI_THROTTLE */
207 TH_BUCKET_SHARE_BG, /* Timeshare thread between MAXPRI_THROTTLE and MINPRI */
208 TH_BUCKET_RUN, /* All runnable threads */
209 TH_BUCKET_SCHED_MAX = TH_BUCKET_RUN, /* Maximum schedulable buckets */
210 TH_BUCKET_MAX,
211 } sched_bucket_t;
212
213 /*
214 * Macro to check for invalid priorities.
215 */
216 #define invalid_pri(pri) ((pri) < MINPRI || (pri) > MAXPRI)
217
218 struct runq_stats {
219 uint64_t count_sum;
220 uint64_t last_change_timestamp;
221 };
222
223 #if defined(CONFIG_SCHED_TIMESHARE_CORE) || defined(CONFIG_SCHED_PROTO)
224
225 struct run_queue {
226 int highq; /* highest runnable queue */
227 bitmap_t bitmap[BITMAP_LEN(NRQS)]; /* run queue bitmap array */
228 int count; /* # of threads total */
229 int urgency; /* level of preemption urgency */
230 circle_queue_head_t queues[NRQS]; /* one for each priority */
231
232 struct runq_stats runq_stats;
233 };
234
235 inline static void
rq_bitmap_set(bitmap_t * __header_indexable map,u_int n)236 rq_bitmap_set(bitmap_t *__header_indexable map, u_int n)
237 {
238 assert(n < NRQS);
239 bitmap_set(map, n);
240 }
241
242 inline static void
rq_bitmap_clear(bitmap_t * __header_indexable map,u_int n)243 rq_bitmap_clear(bitmap_t *__header_indexable map, u_int n)
244 {
245 assert(n < NRQS);
246 bitmap_clear(map, n);
247 }
248
249 #endif /* defined(CONFIG_SCHED_TIMESHARE_CORE) || defined(CONFIG_SCHED_PROTO) */
250
251 typedef struct {
252 queue_head_t pri_queue; /* runnable RT threads for this priority */
253 uint64_t pri_earliest_deadline; /* earliest deadline for this priority */
254 int pri_count; /* # of threads for this priority */
255 uint32_t pri_constraint; /* constraint of earliest deadline thread for this priority */
256 } rt_queue_pri_t;
257
258 struct rt_queue {
259 _Atomic uint64_t earliest_deadline; /* earliest deadline */
260 _Atomic int count; /* # of threads total */
261 _Atomic uint32_t constraint; /* constraint of earliest deadline thread */
262 _Atomic int ed_index; /* index of earliest deadline thread */
263
264 bitmap_t bitmap[BITMAP_LEN(NRTQS)];
265
266 rt_queue_pri_t rt_queue_pri[NRTQS];
267
268 struct runq_stats runq_stats;
269 };
270 typedef struct rt_queue *rt_queue_t;
271
272 #define RT_CONSTRAINT_NONE UINT32_MAX
273 #define RT_DEADLINE_NONE UINT64_MAX
274 #define RT_DEADLINE_QUANTUM_EXPIRED (UINT64_MAX - 1)
275
276 #if defined(CONFIG_SCHED_GRRR_CORE)
277
278 /*
279 * We map standard Mach priorities to an abstract scale that more properly
280 * indicates how we want processor time allocated under contention.
281 */
282 typedef uint8_t grrr_proportional_priority_t;
283 typedef uint8_t grrr_group_index_t;
284
285 #define NUM_GRRR_PROPORTIONAL_PRIORITIES 256
286 #define MAX_GRRR_PROPORTIONAL_PRIORITY ((grrr_proportional_priority_t)255)
287
288 #if 0
289 #define NUM_GRRR_GROUPS 8 /* log(256) */
290 #endif
291
292 #define NUM_GRRR_GROUPS 64 /* 256/4 */
293
294 struct grrr_group {
295 queue_chain_t priority_order; /* next greatest weight group */
296 grrr_proportional_priority_t minpriority;
297 grrr_group_index_t index;
298
299 queue_head_t clients;
300 int count;
301 uint32_t weight;
302 #if 0
303 uint32_t deferred_removal_weight;
304 #endif
305 uint32_t work;
306 thread_t current_client;
307 };
308
309 struct grrr_run_queue {
310 int count;
311 uint32_t last_rescale_tick;
312 struct grrr_group groups[NUM_GRRR_GROUPS];
313 queue_head_t sorted_group_list;
314 uint32_t weight;
315 grrr_group_t current_group;
316
317 struct runq_stats runq_stats;
318 };
319
320 #endif /* defined(CONFIG_SCHED_GRRR_CORE) */
321
322 extern int rt_runq_count(processor_set_t);
323 extern uint64_t rt_runq_earliest_deadline(processor_set_t);
324
325 #if defined(CONFIG_SCHED_MULTIQ)
326 sched_group_t sched_group_create(void);
327 void sched_group_destroy(sched_group_t sched_group);
328 #endif /* defined(CONFIG_SCHED_MULTIQ) */
329
330
331
332 /*
333 * Scheduler routines.
334 */
335
336 /* Handle quantum expiration for an executing thread */
337 extern void thread_quantum_expire(
338 timer_call_param_t processor,
339 timer_call_param_t thread);
340
341 /* Handle preemption timer expiration for an executing thread */
342 extern void thread_preempt_expire(
343 timer_call_param_t processor,
344 timer_call_param_t thread);
345
346 /* Context switch check for current processor */
347 extern ast_t csw_check(
348 thread_t thread,
349 processor_t processor,
350 ast_t check_reason);
351
352 /* Check for pending ASTs */
353 extern void ast_check(processor_t processor);
354
355 extern ast_t update_pending_nonurgent_preemption(processor_t processor, ast_t reason);
356 extern void clear_pending_nonurgent_preemption(processor_t processor);
357
358 extern void sched_update_generation_count(void);
359
360 #if defined(CONFIG_SCHED_TIMESHARE_CORE)
361 extern uint32_t std_quantum, min_std_quantum;
362 extern uint32_t std_quantum_us;
363 #endif /* CONFIG_SCHED_TIMESHARE_CORE */
364
365 extern uint32_t thread_depress_time;
366 extern uint32_t default_timeshare_computation;
367 extern uint32_t default_timeshare_constraint;
368
369 extern uint32_t max_rt_quantum, min_rt_quantum;
370
371 extern int default_preemption_rate;
372
373 #if defined(CONFIG_SCHED_TIMESHARE_CORE)
374
375 /*
376 * Age usage at approximately (1 << SCHED_TICK_SHIFT) times per second
377 * Aging may be deferred during periods where all processors are idle
378 * and cumulatively applied during periods of activity.
379 */
380 #define SCHED_TICK_SHIFT 3
381 #define SCHED_TICK_MAX_DELTA (8)
382
383 extern unsigned sched_tick;
384 extern uint32_t sched_tick_interval;
385
386 #endif /* CONFIG_SCHED_TIMESHARE_CORE */
387
388 extern uint64_t sched_one_second_interval;
389
390 /* Periodic computation of various averages */
391 extern void compute_sched_load(void);
392
393 extern void compute_averages(uint64_t);
394
395 extern void compute_averunnable(
396 void *nrun);
397
398 extern void compute_stack_target(
399 void *arg);
400
401 extern void compute_pageout_gc_throttle(
402 void *arg);
403
404 extern void compute_pmap_gc_throttle(
405 void *arg);
406
407 /*
408 * Conversion factor from usage
409 * to priority.
410 */
411 #if defined(CONFIG_SCHED_TIMESHARE_CORE)
412
413 #define MAX_LOAD (NRQS - 1)
414 #define SCHED_PRI_SHIFT_MAX ((8 * sizeof(uint32_t)) - 1)
415 extern uint32_t sched_pri_shifts[TH_BUCKET_MAX];
416 extern uint32_t sched_fixed_shift;
417 extern int8_t sched_load_shifts[NRQS];
418 extern uint32_t sched_decay_usage_age_factor;
419 void sched_timeshare_consider_maintenance(uint64_t ctime, bool safe_point);
420 #endif /* CONFIG_SCHED_TIMESHARE_CORE */
421
422 void sched_consider_recommended_cores(uint64_t ctime, thread_t thread);
423
424 extern int32_t sched_poll_yield_shift;
425 extern uint64_t sched_safe_rt_duration;
426 extern uint64_t sched_safe_fixed_duration;
427
428 extern uint32_t sched_load_average, sched_mach_factor;
429
430 extern uint32_t avenrun[3], mach_factor[3];
431
432 extern uint64_t max_unsafe_rt_computation;
433 extern uint64_t max_unsafe_fixed_computation;
434 extern uint64_t max_poll_computation;
435
436 extern uint32_t sched_run_buckets[TH_BUCKET_MAX];
437
438 extern uint32_t sched_run_incr(thread_t thread);
439 extern uint32_t sched_run_decr(thread_t thread);
440 extern void sched_update_thread_bucket(thread_t thread);
441
442 extern uint32_t sched_smt_run_incr(thread_t thread);
443 extern uint32_t sched_smt_run_decr(thread_t thread);
444 extern void sched_smt_update_thread_bucket(thread_t thread);
445
446 #define SCHED_DECAY_TICKS 32
447 struct shift_data {
448 int shift1;
449 int shift2;
450 };
451
452 /*
453 * Save the current thread time and compute a delta since the last call for the
454 * scheduler tick.
455 */
456 #define sched_tick_delta(thread, delta) \
457 MACRO_BEGIN \
458 uint64_t _total = recount_thread_time_mach(thread); \
459 (delta) = (typeof(delta))(_total - thread->sched_time_save); \
460 thread->sched_time_save = _total; \
461 MACRO_END
462
463 #define SCHED_MAX_BACKUP_PROCESSORS 7
464 #if defined(__x86_64__)
465 #define SCHED_DEFAULT_BACKUP_PROCESSORS 1
466 #define SCHED_DEFAULT_BACKUP_PROCESSORS_SMT 2
467 #else
468 #define SCHED_DEFAULT_BACKUP_PROCESSORS 0
469 #define SCHED_DEFAULT_BACKUP_PROCESSORS_SMT 0
470 #endif
471 extern int sched_rt_n_backup_processors;
472
473 extern bool system_is_SMT;
474
475 #endif /* _KERN_SCHED_H_ */
476