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32 * Mach Operating System
33 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
34 * All Rights Reserved.
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.
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.
46 * Carnegie Mellon requests users of this software to return to
48 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
49 * School of Computer Science
50 * Carnegie Mellon University
51 * Pittsburgh PA 15213-3890
53 * any improvements or extensions that they make and grant Carnegie Mellon
54 * the rights to redistribute these changes.
60 * Author: Avadis Tevanian, Jr.
63 * Header file for scheduler.
67 #ifndef _KERN_SCHED_H_
68 #define _KERN_SCHED_H_
70 #include <mach/policy.h>
71 #include <kern/kern_types.h>
72 #include <kern/queue.h>
73 #include <kern/lock.h>
74 #include <kern/macro_help.h>
75 #include <kern/timer_call.h>
78 #define NRQS 128 /* 128 levels per run queue */
79 #define NRQBM (NRQS / 32) /* number of words per bit map */
81 #define MAXPRI (NRQS-1)
82 #define MINPRI IDLEPRI /* lowest legal priority schedulable */
83 #define IDLEPRI 0 /* idle thread priority */
86 * High-level priority assignments
88 *************************************************************************
89 * 127 Reserved (real-time)
95 * 96 Reserved (real-time)
102 * 80 Kernel mode only
103 * 79 System high priority
109 * 64 System high priority
110 * 63 Elevated priorities
116 * 52 Elevated priorities
117 * 51 Elevated priorities (incl. BSD +nice)
123 * 32 Elevated priorities (incl. BSD +nice)
124 * 31 Default (default base for threads)
125 * 30 Lowered priorities (incl. BSD -nice)
131 * 11 Lowered priorities (incl. BSD -nice)
132 * 10 Lowered priorities (aged pri's)
138 * 0 Lowered priorities (aged pri's / idle)
139 *************************************************************************
142 #define BASEPRI_RTQUEUES (BASEPRI_REALTIME + 1) /* 97 */
143 #define BASEPRI_REALTIME (MAXPRI - (NRQS / 4) + 1) /* 96 */
145 #define MAXPRI_KERNEL (BASEPRI_REALTIME - 1) /* 95 */
146 #define BASEPRI_PREEMPT (MAXPRI_KERNEL - 2) /* 93 */
147 #define BASEPRI_KERNEL (MINPRI_KERNEL + 1) /* 81 */
148 #define MINPRI_KERNEL (MAXPRI_KERNEL - (NRQS / 8) + 1) /* 80 */
150 #define MAXPRI_RESERVED (MINPRI_KERNEL - 1) /* 79 */
151 #define MINPRI_RESERVED (MAXPRI_RESERVED - (NRQS / 8) + 1) /* 64 */
153 #define MAXPRI_USER (MINPRI_RESERVED - 1) /* 63 */
154 #define BASEPRI_CONTROL (BASEPRI_DEFAULT + 17) /* 48 */
155 #define BASEPRI_FOREGROUND (BASEPRI_DEFAULT + 16) /* 47 */
156 #define BASEPRI_BACKGROUND (BASEPRI_DEFAULT + 15) /* 46 */
157 #define BASEPRI_DEFAULT (MAXPRI_USER - (NRQS / 4)) /* 31 */
158 #define MAXPRI_THROTTLE (MINPRI + 4) /* 4 */
159 #define MINPRI_USER MINPRI /* 0 */
161 #ifdef CONFIG_EMBEDDED
162 #define DEPRESSPRI MAXPRI_THROTTLE
164 #define DEPRESSPRI MINPRI /* depress priority */
167 /* Type used for thread->sched_mode and saved_mode */
169 TH_MODE_NONE
= 0, /* unassigned, usually for saved_mode only */
170 TH_MODE_REALTIME
, /* time constraints supplied */
171 TH_MODE_FIXED
, /* use fixed priorities, no decay */
172 TH_MODE_TIMESHARE
, /* use timesharing algorithm */
173 TH_MODE_FAIRSHARE
/* use fair-share scheduling */
177 * Macro to check for invalid priorities.
179 #define invalid_pri(pri) ((pri) < MINPRI || (pri) > MAXPRI)
183 uint64_t last_change_timestamp
;
186 #if defined(CONFIG_SCHED_TRADITIONAL) || defined(CONFIG_SCHED_PROTO) || defined(CONFIG_SCHED_FIXEDPRIORITY)
189 int highq
; /* highest runnable queue */
190 int bitmap
[NRQBM
]; /* run queue bitmap array */
191 int count
; /* # of threads total */
192 int urgency
; /* level of preemption urgency */
193 queue_head_t queues
[NRQS
]; /* one for each priority */
195 struct runq_stats runq_stats
;
198 #endif /* defined(CONFIG_SCHED_TRADITIONAL) || defined(CONFIG_SCHED_PROTO) || defined(CONFIG_SCHED_FIXEDPRIORITY) */
201 int count
; /* # of threads total */
202 queue_head_t queue
; /* all runnable RT threads */
204 struct runq_stats runq_stats
;
207 #if defined(CONFIG_SCHED_TRADITIONAL) || defined(CONFIG_SCHED_PROTO) || defined(CONFIG_SCHED_FIXEDPRIORITY)
208 struct fairshare_queue
{
209 int count
; /* # of threads total */
210 queue_head_t queue
; /* all runnable threads demoted to fairshare scheduling */
212 struct runq_stats runq_stats
;
216 #if defined(CONFIG_SCHED_GRRR_CORE)
219 * We map standard Mach priorities to an abstract scale that more properly
220 * indicates how we want processor time allocated under contention.
222 typedef uint8_t grrr_proportional_priority_t
;
223 typedef uint8_t grrr_group_index_t
;
225 #define NUM_GRRR_PROPORTIONAL_PRIORITIES 256
226 #define MAX_GRRR_PROPORTIONAL_PRIORITY ((grrr_proportional_priority_t)255)
229 #define NUM_GRRR_GROUPS 8 /* log(256) */
232 #define NUM_GRRR_GROUPS 64 /* 256/4 */
235 queue_chain_t priority_order
; /* next greatest weight group */
236 grrr_proportional_priority_t minpriority
;
237 grrr_group_index_t index
;
239 queue_head_t clients
;
243 uint32_t deferred_removal_weight
;
246 thread_t current_client
;
249 struct grrr_run_queue
{
251 uint32_t last_rescale_tick
;
252 struct grrr_group groups
[NUM_GRRR_GROUPS
];
253 queue_head_t sorted_group_list
;
255 grrr_group_t current_group
;
257 struct runq_stats runq_stats
;
260 #endif /* defined(CONFIG_SCHED_GRRR_CORE) */
262 #define first_timeslice(processor) ((processor)->timeslice > 0)
264 extern struct rt_queue rt_runq
;
267 * Scheduler routines.
270 /* Handle quantum expiration for an executing thread */
271 extern void thread_quantum_expire(
272 timer_call_param_t processor
,
273 timer_call_param_t thread
);
275 /* Context switch check for current processor */
276 extern ast_t
csw_check(processor_t processor
);
278 #if defined(CONFIG_SCHED_TRADITIONAL)
279 extern uint32_t std_quantum
, min_std_quantum
;
280 extern uint32_t std_quantum_us
;
283 extern uint32_t thread_depress_time
;
284 extern uint32_t default_timeshare_computation
;
285 extern uint32_t default_timeshare_constraint
;
287 extern uint32_t max_rt_quantum
, min_rt_quantum
;
289 extern int default_preemption_rate
;
290 extern int default_bg_preemption_rate
;
292 #if defined(CONFIG_SCHED_TRADITIONAL)
295 * Age usage (1 << SCHED_TICK_SHIFT) times per second.
297 #define SCHED_TICK_SHIFT 3
299 extern unsigned sched_tick
;
300 extern uint32_t sched_tick_interval
;
302 #endif /* CONFIG_SCHED_TRADITIONAL */
304 extern uint64_t sched_one_second_interval
;
306 /* Periodic computation of various averages */
307 extern void compute_averages(void);
309 extern void compute_averunnable(
312 extern void compute_stack_target(
315 extern void compute_memory_pressure(
318 extern void compute_zone_gc_throttle(
321 extern void compute_pageout_gc_throttle(
324 extern void compute_pmap_gc_throttle(
328 * Conversion factor from usage
331 #if defined(CONFIG_SCHED_TRADITIONAL)
332 extern uint32_t sched_pri_shift
;
333 extern uint32_t sched_fixed_shift
;
334 extern int8_t sched_load_shifts
[NRQS
];
337 extern int32_t sched_poll_yield_shift
;
338 extern uint64_t sched_safe_duration
;
340 extern uint32_t sched_run_count
, sched_share_count
;
341 extern uint32_t sched_load_average
, sched_mach_factor
;
343 extern uint32_t avenrun
[3], mach_factor
[3];
345 extern uint64_t max_unsafe_computation
;
346 extern uint64_t max_poll_computation
;
348 #define sched_run_incr() \
350 hw_atomic_add(&sched_run_count, 1); \
353 #define sched_run_decr() \
355 hw_atomic_sub(&sched_run_count, 1); \
358 #define sched_share_incr() \
360 (void)hw_atomic_add(&sched_share_count, 1); \
363 #define sched_share_decr() \
365 (void)hw_atomic_sub(&sched_share_count, 1); \
369 * thread_timer_delta macro takes care of both thread timers.
371 #define thread_timer_delta(thread, delta) \
373 (delta) = (typeof(delta))timer_delta(&(thread)->system_timer, \
374 &(thread)->system_timer_save); \
375 (delta) += (typeof(delta))timer_delta(&(thread)->user_timer, \
376 &(thread)->user_timer_save); \
379 #endif /* _KERN_SCHED_H_ */