sched_ule.c revision 211515
1/*-
2 * Copyright (c) 2002-2007, Jeffrey Roberson <jeff@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice unmodified, this list of conditions, and the following
10 *    disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27/*
28 * This file implements the ULE scheduler.  ULE supports independent CPU
29 * run queues and fine grain locking.  It has superior interactive
30 * performance under load even on uni-processor systems.
31 *
32 * etymology:
33 *   ULE is the last three letters in schedule.  It owes its name to a
34 * generic user created for a scheduling system by Paul Mikesell at
35 * Isilon Systems and a general lack of creativity on the part of the author.
36 */
37
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: head/sys/kern/sched_ule.c 211515 2010-08-19 16:41:27Z jhb $");
40
41#include "opt_hwpmc_hooks.h"
42#include "opt_kdtrace.h"
43#include "opt_sched.h"
44
45#include <sys/param.h>
46#include <sys/systm.h>
47#include <sys/kdb.h>
48#include <sys/kernel.h>
49#include <sys/ktr.h>
50#include <sys/lock.h>
51#include <sys/mutex.h>
52#include <sys/proc.h>
53#include <sys/resource.h>
54#include <sys/resourcevar.h>
55#include <sys/sched.h>
56#include <sys/smp.h>
57#include <sys/sx.h>
58#include <sys/sysctl.h>
59#include <sys/sysproto.h>
60#include <sys/turnstile.h>
61#include <sys/umtx.h>
62#include <sys/vmmeter.h>
63#include <sys/cpuset.h>
64#include <sys/sbuf.h>
65
66#ifdef HWPMC_HOOKS
67#include <sys/pmckern.h>
68#endif
69
70#ifdef KDTRACE_HOOKS
71#include <sys/dtrace_bsd.h>
72int				dtrace_vtime_active;
73dtrace_vtime_switch_func_t	dtrace_vtime_switch_func;
74#endif
75
76#include <machine/cpu.h>
77#include <machine/smp.h>
78
79#if defined(__sparc64__)
80#error "This architecture is not currently compatible with ULE"
81#endif
82
83#define	KTR_ULE	0
84
85#define	TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX)))
86#define	TDQ_NAME_LEN	(sizeof("sched lock ") + sizeof(__XSTRING(MAXCPU)))
87#define	TDQ_LOADNAME_LEN	(PCPU_NAME_LEN + sizeof(" load"))
88
89/*
90 * Thread scheduler specific section.  All fields are protected
91 * by the thread lock.
92 */
93struct td_sched {
94	struct runq	*ts_runq;	/* Run-queue we're queued on. */
95	short		ts_flags;	/* TSF_* flags. */
96	u_char		ts_cpu;		/* CPU that we have affinity for. */
97	int		ts_rltick;	/* Real last tick, for affinity. */
98	int		ts_slice;	/* Ticks of slice remaining. */
99	u_int		ts_slptime;	/* Number of ticks we vol. slept */
100	u_int		ts_runtime;	/* Number of ticks we were running */
101	int		ts_ltick;	/* Last tick that we were running on */
102	int		ts_incrtick;	/* Last tick that we incremented on */
103	int		ts_ftick;	/* First tick that we were running on */
104	int		ts_ticks;	/* Tick count */
105#ifdef KTR
106	char		ts_name[TS_NAME_LEN];
107#endif
108};
109/* flags kept in ts_flags */
110#define	TSF_BOUND	0x0001		/* Thread can not migrate. */
111#define	TSF_XFERABLE	0x0002		/* Thread was added as transferable. */
112
113static struct td_sched td_sched0;
114
115#define	THREAD_CAN_MIGRATE(td)	((td)->td_pinned == 0)
116#define	THREAD_CAN_SCHED(td, cpu)	\
117    CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask)
118
119/*
120 * Cpu percentage computation macros and defines.
121 *
122 * SCHED_TICK_SECS:	Number of seconds to average the cpu usage across.
123 * SCHED_TICK_TARG:	Number of hz ticks to average the cpu usage across.
124 * SCHED_TICK_MAX:	Maximum number of ticks before scaling back.
125 * SCHED_TICK_SHIFT:	Shift factor to avoid rounding away results.
126 * SCHED_TICK_HZ:	Compute the number of hz ticks for a given ticks count.
127 * SCHED_TICK_TOTAL:	Gives the amount of time we've been recording ticks.
128 */
129#define	SCHED_TICK_SECS		10
130#define	SCHED_TICK_TARG		(hz * SCHED_TICK_SECS)
131#define	SCHED_TICK_MAX		(SCHED_TICK_TARG + hz)
132#define	SCHED_TICK_SHIFT	10
133#define	SCHED_TICK_HZ(ts)	((ts)->ts_ticks >> SCHED_TICK_SHIFT)
134#define	SCHED_TICK_TOTAL(ts)	(max((ts)->ts_ltick - (ts)->ts_ftick, hz))
135
136/*
137 * These macros determine priorities for non-interactive threads.  They are
138 * assigned a priority based on their recent cpu utilization as expressed
139 * by the ratio of ticks to the tick total.  NHALF priorities at the start
140 * and end of the MIN to MAX timeshare range are only reachable with negative
141 * or positive nice respectively.
142 *
143 * PRI_RANGE:	Priority range for utilization dependent priorities.
144 * PRI_NRESV:	Number of nice values.
145 * PRI_TICKS:	Compute a priority in PRI_RANGE from the ticks count and total.
146 * PRI_NICE:	Determines the part of the priority inherited from nice.
147 */
148#define	SCHED_PRI_NRESV		(PRIO_MAX - PRIO_MIN)
149#define	SCHED_PRI_NHALF		(SCHED_PRI_NRESV / 2)
150#define	SCHED_PRI_MIN		(PRI_MIN_TIMESHARE + SCHED_PRI_NHALF)
151#define	SCHED_PRI_MAX		(PRI_MAX_TIMESHARE - SCHED_PRI_NHALF)
152#define	SCHED_PRI_RANGE		(SCHED_PRI_MAX - SCHED_PRI_MIN)
153#define	SCHED_PRI_TICKS(ts)						\
154    (SCHED_TICK_HZ((ts)) /						\
155    (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE))
156#define	SCHED_PRI_NICE(nice)	(nice)
157
158/*
159 * These determine the interactivity of a process.  Interactivity differs from
160 * cpu utilization in that it expresses the voluntary time slept vs time ran
161 * while cpu utilization includes all time not running.  This more accurately
162 * models the intent of the thread.
163 *
164 * SLP_RUN_MAX:	Maximum amount of sleep time + run time we'll accumulate
165 *		before throttling back.
166 * SLP_RUN_FORK:	Maximum slp+run time to inherit at fork time.
167 * INTERACT_MAX:	Maximum interactivity value.  Smaller is better.
168 * INTERACT_THRESH:	Threshhold for placement on the current runq.
169 */
170#define	SCHED_SLP_RUN_MAX	((hz * 5) << SCHED_TICK_SHIFT)
171#define	SCHED_SLP_RUN_FORK	((hz / 2) << SCHED_TICK_SHIFT)
172#define	SCHED_INTERACT_MAX	(100)
173#define	SCHED_INTERACT_HALF	(SCHED_INTERACT_MAX / 2)
174#define	SCHED_INTERACT_THRESH	(30)
175
176/*
177 * tickincr:		Converts a stathz tick into a hz domain scaled by
178 *			the shift factor.  Without the shift the error rate
179 *			due to rounding would be unacceptably high.
180 * realstathz:		stathz is sometimes 0 and run off of hz.
181 * sched_slice:		Runtime of each thread before rescheduling.
182 * preempt_thresh:	Priority threshold for preemption and remote IPIs.
183 */
184static int sched_interact = SCHED_INTERACT_THRESH;
185static int realstathz;
186static int tickincr;
187static int sched_slice = 1;
188#ifdef PREEMPTION
189#ifdef FULL_PREEMPTION
190static int preempt_thresh = PRI_MAX_IDLE;
191#else
192static int preempt_thresh = PRI_MIN_KERN;
193#endif
194#else
195static int preempt_thresh = 0;
196#endif
197static int static_boost = PRI_MIN_TIMESHARE;
198static int sched_idlespins = 10000;
199static int sched_idlespinthresh = 4;
200
201/*
202 * tdq - per processor runqs and statistics.  All fields are protected by the
203 * tdq_lock.  The load and lowpri may be accessed without to avoid excess
204 * locking in sched_pickcpu();
205 */
206struct tdq {
207	/* Ordered to improve efficiency of cpu_search() and switch(). */
208	struct mtx	tdq_lock;		/* run queue lock. */
209	struct cpu_group *tdq_cg;		/* Pointer to cpu topology. */
210	volatile int	tdq_load;		/* Aggregate load. */
211	int		tdq_sysload;		/* For loadavg, !ITHD load. */
212	int		tdq_transferable;	/* Transferable thread count. */
213	short		tdq_switchcnt;		/* Switches this tick. */
214	short		tdq_oldswitchcnt;	/* Switches last tick. */
215	u_char		tdq_lowpri;		/* Lowest priority thread. */
216	u_char		tdq_ipipending;		/* IPI pending. */
217	u_char		tdq_idx;		/* Current insert index. */
218	u_char		tdq_ridx;		/* Current removal index. */
219	struct runq	tdq_realtime;		/* real-time run queue. */
220	struct runq	tdq_timeshare;		/* timeshare run queue. */
221	struct runq	tdq_idle;		/* Queue of IDLE threads. */
222	char		tdq_name[TDQ_NAME_LEN];
223#ifdef KTR
224	char		tdq_loadname[TDQ_LOADNAME_LEN];
225#endif
226} __aligned(64);
227
228/* Idle thread states and config. */
229#define	TDQ_RUNNING	1
230#define	TDQ_IDLE	2
231
232#ifdef SMP
233struct cpu_group *cpu_top;		/* CPU topology */
234
235#define	SCHED_AFFINITY_DEFAULT	(max(1, hz / 1000))
236#define	SCHED_AFFINITY(ts, t)	((ts)->ts_rltick > ticks - ((t) * affinity))
237
238/*
239 * Run-time tunables.
240 */
241static int rebalance = 1;
242static int balance_interval = 128;	/* Default set in sched_initticks(). */
243static int affinity;
244static int steal_htt = 1;
245static int steal_idle = 1;
246static int steal_thresh = 2;
247
248/*
249 * One thread queue per processor.
250 */
251static struct tdq	tdq_cpu[MAXCPU];
252static struct tdq	*balance_tdq;
253static int balance_ticks;
254
255#define	TDQ_SELF()	(&tdq_cpu[PCPU_GET(cpuid)])
256#define	TDQ_CPU(x)	(&tdq_cpu[(x)])
257#define	TDQ_ID(x)	((int)((x) - tdq_cpu))
258#else	/* !SMP */
259static struct tdq	tdq_cpu;
260
261#define	TDQ_ID(x)	(0)
262#define	TDQ_SELF()	(&tdq_cpu)
263#define	TDQ_CPU(x)	(&tdq_cpu)
264#endif
265
266#define	TDQ_LOCK_ASSERT(t, type)	mtx_assert(TDQ_LOCKPTR((t)), (type))
267#define	TDQ_LOCK(t)		mtx_lock_spin(TDQ_LOCKPTR((t)))
268#define	TDQ_LOCK_FLAGS(t, f)	mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f))
269#define	TDQ_UNLOCK(t)		mtx_unlock_spin(TDQ_LOCKPTR((t)))
270#define	TDQ_LOCKPTR(t)		(&(t)->tdq_lock)
271
272static void sched_priority(struct thread *);
273static void sched_thread_priority(struct thread *, u_char);
274static int sched_interact_score(struct thread *);
275static void sched_interact_update(struct thread *);
276static void sched_interact_fork(struct thread *);
277static void sched_pctcpu_update(struct td_sched *);
278
279/* Operations on per processor queues */
280static struct thread *tdq_choose(struct tdq *);
281static void tdq_setup(struct tdq *);
282static void tdq_load_add(struct tdq *, struct thread *);
283static void tdq_load_rem(struct tdq *, struct thread *);
284static __inline void tdq_runq_add(struct tdq *, struct thread *, int);
285static __inline void tdq_runq_rem(struct tdq *, struct thread *);
286static inline int sched_shouldpreempt(int, int, int);
287void tdq_print(int cpu);
288static void runq_print(struct runq *rq);
289static void tdq_add(struct tdq *, struct thread *, int);
290#ifdef SMP
291static int tdq_move(struct tdq *, struct tdq *);
292static int tdq_idled(struct tdq *);
293static void tdq_notify(struct tdq *, struct thread *);
294static struct thread *tdq_steal(struct tdq *, int);
295static struct thread *runq_steal(struct runq *, int);
296static int sched_pickcpu(struct thread *, int);
297static void sched_balance(void);
298static int sched_balance_pair(struct tdq *, struct tdq *);
299static inline struct tdq *sched_setcpu(struct thread *, int, int);
300static inline void thread_unblock_switch(struct thread *, struct mtx *);
301static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int);
302static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS);
303static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb,
304    struct cpu_group *cg, int indent);
305#endif
306
307static void sched_setup(void *dummy);
308SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
309
310static void sched_initticks(void *dummy);
311SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks,
312    NULL);
313
314/*
315 * Print the threads waiting on a run-queue.
316 */
317static void
318runq_print(struct runq *rq)
319{
320	struct rqhead *rqh;
321	struct thread *td;
322	int pri;
323	int j;
324	int i;
325
326	for (i = 0; i < RQB_LEN; i++) {
327		printf("\t\trunq bits %d 0x%zx\n",
328		    i, rq->rq_status.rqb_bits[i]);
329		for (j = 0; j < RQB_BPW; j++)
330			if (rq->rq_status.rqb_bits[i] & (1ul << j)) {
331				pri = j + (i << RQB_L2BPW);
332				rqh = &rq->rq_queues[pri];
333				TAILQ_FOREACH(td, rqh, td_runq) {
334					printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n",
335					    td, td->td_name, td->td_priority,
336					    td->td_rqindex, pri);
337				}
338			}
339	}
340}
341
342/*
343 * Print the status of a per-cpu thread queue.  Should be a ddb show cmd.
344 */
345void
346tdq_print(int cpu)
347{
348	struct tdq *tdq;
349
350	tdq = TDQ_CPU(cpu);
351
352	printf("tdq %d:\n", TDQ_ID(tdq));
353	printf("\tlock            %p\n", TDQ_LOCKPTR(tdq));
354	printf("\tLock name:      %s\n", tdq->tdq_name);
355	printf("\tload:           %d\n", tdq->tdq_load);
356	printf("\tswitch cnt:     %d\n", tdq->tdq_switchcnt);
357	printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt);
358	printf("\ttimeshare idx:  %d\n", tdq->tdq_idx);
359	printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx);
360	printf("\tload transferable: %d\n", tdq->tdq_transferable);
361	printf("\tlowest priority:   %d\n", tdq->tdq_lowpri);
362	printf("\trealtime runq:\n");
363	runq_print(&tdq->tdq_realtime);
364	printf("\ttimeshare runq:\n");
365	runq_print(&tdq->tdq_timeshare);
366	printf("\tidle runq:\n");
367	runq_print(&tdq->tdq_idle);
368}
369
370static inline int
371sched_shouldpreempt(int pri, int cpri, int remote)
372{
373	/*
374	 * If the new priority is not better than the current priority there is
375	 * nothing to do.
376	 */
377	if (pri >= cpri)
378		return (0);
379	/*
380	 * Always preempt idle.
381	 */
382	if (cpri >= PRI_MIN_IDLE)
383		return (1);
384	/*
385	 * If preemption is disabled don't preempt others.
386	 */
387	if (preempt_thresh == 0)
388		return (0);
389	/*
390	 * Preempt if we exceed the threshold.
391	 */
392	if (pri <= preempt_thresh)
393		return (1);
394	/*
395	 * If we're realtime or better and there is timeshare or worse running
396	 * preempt only remote processors.
397	 */
398	if (remote && pri <= PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME)
399		return (1);
400	return (0);
401}
402
403#define	TS_RQ_PPQ	(((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS)
404/*
405 * Add a thread to the actual run-queue.  Keeps transferable counts up to
406 * date with what is actually on the run-queue.  Selects the correct
407 * queue position for timeshare threads.
408 */
409static __inline void
410tdq_runq_add(struct tdq *tdq, struct thread *td, int flags)
411{
412	struct td_sched *ts;
413	u_char pri;
414
415	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
416	THREAD_LOCK_ASSERT(td, MA_OWNED);
417
418	pri = td->td_priority;
419	ts = td->td_sched;
420	TD_SET_RUNQ(td);
421	if (THREAD_CAN_MIGRATE(td)) {
422		tdq->tdq_transferable++;
423		ts->ts_flags |= TSF_XFERABLE;
424	}
425	if (pri <= PRI_MAX_REALTIME) {
426		ts->ts_runq = &tdq->tdq_realtime;
427	} else if (pri <= PRI_MAX_TIMESHARE) {
428		ts->ts_runq = &tdq->tdq_timeshare;
429		KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE,
430			("Invalid priority %d on timeshare runq", pri));
431		/*
432		 * This queue contains only priorities between MIN and MAX
433		 * realtime.  Use the whole queue to represent these values.
434		 */
435		if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) {
436			pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ;
437			pri = (pri + tdq->tdq_idx) % RQ_NQS;
438			/*
439			 * This effectively shortens the queue by one so we
440			 * can have a one slot difference between idx and
441			 * ridx while we wait for threads to drain.
442			 */
443			if (tdq->tdq_ridx != tdq->tdq_idx &&
444			    pri == tdq->tdq_ridx)
445				pri = (unsigned char)(pri - 1) % RQ_NQS;
446		} else
447			pri = tdq->tdq_ridx;
448		runq_add_pri(ts->ts_runq, td, pri, flags);
449		return;
450	} else
451		ts->ts_runq = &tdq->tdq_idle;
452	runq_add(ts->ts_runq, td, flags);
453}
454
455/*
456 * Remove a thread from a run-queue.  This typically happens when a thread
457 * is selected to run.  Running threads are not on the queue and the
458 * transferable count does not reflect them.
459 */
460static __inline void
461tdq_runq_rem(struct tdq *tdq, struct thread *td)
462{
463	struct td_sched *ts;
464
465	ts = td->td_sched;
466	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
467	KASSERT(ts->ts_runq != NULL,
468	    ("tdq_runq_remove: thread %p null ts_runq", td));
469	if (ts->ts_flags & TSF_XFERABLE) {
470		tdq->tdq_transferable--;
471		ts->ts_flags &= ~TSF_XFERABLE;
472	}
473	if (ts->ts_runq == &tdq->tdq_timeshare) {
474		if (tdq->tdq_idx != tdq->tdq_ridx)
475			runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx);
476		else
477			runq_remove_idx(ts->ts_runq, td, NULL);
478	} else
479		runq_remove(ts->ts_runq, td);
480}
481
482/*
483 * Load is maintained for all threads RUNNING and ON_RUNQ.  Add the load
484 * for this thread to the referenced thread queue.
485 */
486static void
487tdq_load_add(struct tdq *tdq, struct thread *td)
488{
489
490	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
491	THREAD_LOCK_ASSERT(td, MA_OWNED);
492
493	tdq->tdq_load++;
494	if ((td->td_flags & TDF_NOLOAD) == 0)
495		tdq->tdq_sysload++;
496	KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
497}
498
499/*
500 * Remove the load from a thread that is transitioning to a sleep state or
501 * exiting.
502 */
503static void
504tdq_load_rem(struct tdq *tdq, struct thread *td)
505{
506
507	THREAD_LOCK_ASSERT(td, MA_OWNED);
508	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
509	KASSERT(tdq->tdq_load != 0,
510	    ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq)));
511
512	tdq->tdq_load--;
513	if ((td->td_flags & TDF_NOLOAD) == 0)
514		tdq->tdq_sysload--;
515	KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
516}
517
518/*
519 * Set lowpri to its exact value by searching the run-queue and
520 * evaluating curthread.  curthread may be passed as an optimization.
521 */
522static void
523tdq_setlowpri(struct tdq *tdq, struct thread *ctd)
524{
525	struct thread *td;
526
527	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
528	if (ctd == NULL)
529		ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread;
530	td = tdq_choose(tdq);
531	if (td == NULL || td->td_priority > ctd->td_priority)
532		tdq->tdq_lowpri = ctd->td_priority;
533	else
534		tdq->tdq_lowpri = td->td_priority;
535}
536
537#ifdef SMP
538struct cpu_search {
539	cpuset_t cs_mask;
540	u_int	cs_load;
541	u_int	cs_cpu;
542	int	cs_limit;	/* Min priority for low min load for high. */
543};
544
545#define	CPU_SEARCH_LOWEST	0x1
546#define	CPU_SEARCH_HIGHEST	0x2
547#define	CPU_SEARCH_BOTH		(CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST)
548
549#define	CPUSET_FOREACH(cpu, mask)				\
550	for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++)		\
551		if ((mask) & 1 << (cpu))
552
553static __inline int cpu_search(struct cpu_group *cg, struct cpu_search *low,
554    struct cpu_search *high, const int match);
555int cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low);
556int cpu_search_highest(struct cpu_group *cg, struct cpu_search *high);
557int cpu_search_both(struct cpu_group *cg, struct cpu_search *low,
558    struct cpu_search *high);
559
560/*
561 * This routine compares according to the match argument and should be
562 * reduced in actual instantiations via constant propagation and dead code
563 * elimination.
564 */
565static __inline int
566cpu_compare(int cpu, struct cpu_search *low, struct cpu_search *high,
567    const int match)
568{
569	struct tdq *tdq;
570
571	tdq = TDQ_CPU(cpu);
572	if (match & CPU_SEARCH_LOWEST)
573		if (CPU_ISSET(cpu, &low->cs_mask) &&
574		    tdq->tdq_load < low->cs_load &&
575		    tdq->tdq_lowpri > low->cs_limit) {
576			low->cs_cpu = cpu;
577			low->cs_load = tdq->tdq_load;
578		}
579	if (match & CPU_SEARCH_HIGHEST)
580		if (CPU_ISSET(cpu, &high->cs_mask) &&
581		    tdq->tdq_load >= high->cs_limit &&
582		    tdq->tdq_load > high->cs_load &&
583		    tdq->tdq_transferable) {
584			high->cs_cpu = cpu;
585			high->cs_load = tdq->tdq_load;
586		}
587	return (tdq->tdq_load);
588}
589
590/*
591 * Search the tree of cpu_groups for the lowest or highest loaded cpu
592 * according to the match argument.  This routine actually compares the
593 * load on all paths through the tree and finds the least loaded cpu on
594 * the least loaded path, which may differ from the least loaded cpu in
595 * the system.  This balances work among caches and busses.
596 *
597 * This inline is instantiated in three forms below using constants for the
598 * match argument.  It is reduced to the minimum set for each case.  It is
599 * also recursive to the depth of the tree.
600 */
601static __inline int
602cpu_search(struct cpu_group *cg, struct cpu_search *low,
603    struct cpu_search *high, const int match)
604{
605	int total;
606
607	total = 0;
608	if (cg->cg_children) {
609		struct cpu_search lgroup;
610		struct cpu_search hgroup;
611		struct cpu_group *child;
612		u_int lload;
613		int hload;
614		int load;
615		int i;
616
617		lload = -1;
618		hload = -1;
619		for (i = 0; i < cg->cg_children; i++) {
620			child = &cg->cg_child[i];
621			if (match & CPU_SEARCH_LOWEST) {
622				lgroup = *low;
623				lgroup.cs_load = -1;
624			}
625			if (match & CPU_SEARCH_HIGHEST) {
626				hgroup = *high;
627				lgroup.cs_load = 0;
628			}
629			switch (match) {
630			case CPU_SEARCH_LOWEST:
631				load = cpu_search_lowest(child, &lgroup);
632				break;
633			case CPU_SEARCH_HIGHEST:
634				load = cpu_search_highest(child, &hgroup);
635				break;
636			case CPU_SEARCH_BOTH:
637				load = cpu_search_both(child, &lgroup, &hgroup);
638				break;
639			}
640			total += load;
641			if (match & CPU_SEARCH_LOWEST)
642				if (load < lload || low->cs_cpu == -1) {
643					*low = lgroup;
644					lload = load;
645				}
646			if (match & CPU_SEARCH_HIGHEST)
647				if (load > hload || high->cs_cpu == -1) {
648					hload = load;
649					*high = hgroup;
650				}
651		}
652	} else {
653		int cpu;
654
655		CPUSET_FOREACH(cpu, cg->cg_mask)
656			total += cpu_compare(cpu, low, high, match);
657	}
658	return (total);
659}
660
661/*
662 * cpu_search instantiations must pass constants to maintain the inline
663 * optimization.
664 */
665int
666cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low)
667{
668	return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST);
669}
670
671int
672cpu_search_highest(struct cpu_group *cg, struct cpu_search *high)
673{
674	return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST);
675}
676
677int
678cpu_search_both(struct cpu_group *cg, struct cpu_search *low,
679    struct cpu_search *high)
680{
681	return cpu_search(cg, low, high, CPU_SEARCH_BOTH);
682}
683
684/*
685 * Find the cpu with the least load via the least loaded path that has a
686 * lowpri greater than pri  pri.  A pri of -1 indicates any priority is
687 * acceptable.
688 */
689static inline int
690sched_lowest(struct cpu_group *cg, cpuset_t mask, int pri)
691{
692	struct cpu_search low;
693
694	low.cs_cpu = -1;
695	low.cs_load = -1;
696	low.cs_mask = mask;
697	low.cs_limit = pri;
698	cpu_search_lowest(cg, &low);
699	return low.cs_cpu;
700}
701
702/*
703 * Find the cpu with the highest load via the highest loaded path.
704 */
705static inline int
706sched_highest(struct cpu_group *cg, cpuset_t mask, int minload)
707{
708	struct cpu_search high;
709
710	high.cs_cpu = -1;
711	high.cs_load = 0;
712	high.cs_mask = mask;
713	high.cs_limit = minload;
714	cpu_search_highest(cg, &high);
715	return high.cs_cpu;
716}
717
718/*
719 * Simultaneously find the highest and lowest loaded cpu reachable via
720 * cg.
721 */
722static inline void
723sched_both(struct cpu_group *cg, cpuset_t mask, int *lowcpu, int *highcpu)
724{
725	struct cpu_search high;
726	struct cpu_search low;
727
728	low.cs_cpu = -1;
729	low.cs_limit = -1;
730	low.cs_load = -1;
731	low.cs_mask = mask;
732	high.cs_load = 0;
733	high.cs_cpu = -1;
734	high.cs_limit = -1;
735	high.cs_mask = mask;
736	cpu_search_both(cg, &low, &high);
737	*lowcpu = low.cs_cpu;
738	*highcpu = high.cs_cpu;
739	return;
740}
741
742static void
743sched_balance_group(struct cpu_group *cg)
744{
745	cpuset_t mask;
746	int high;
747	int low;
748	int i;
749
750	CPU_FILL(&mask);
751	for (;;) {
752		sched_both(cg, mask, &low, &high);
753		if (low == high || low == -1 || high == -1)
754			break;
755		if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low)))
756			break;
757		/*
758		 * If we failed to move any threads determine which cpu
759		 * to kick out of the set and try again.
760	 	 */
761		if (TDQ_CPU(high)->tdq_transferable == 0)
762			CPU_CLR(high, &mask);
763		else
764			CPU_CLR(low, &mask);
765	}
766
767	for (i = 0; i < cg->cg_children; i++)
768		sched_balance_group(&cg->cg_child[i]);
769}
770
771static void
772sched_balance(void)
773{
774	struct tdq *tdq;
775
776	/*
777	 * Select a random time between .5 * balance_interval and
778	 * 1.5 * balance_interval.
779	 */
780	balance_ticks = max(balance_interval / 2, 1);
781	balance_ticks += random() % balance_interval;
782	if (smp_started == 0 || rebalance == 0)
783		return;
784	tdq = TDQ_SELF();
785	TDQ_UNLOCK(tdq);
786	sched_balance_group(cpu_top);
787	TDQ_LOCK(tdq);
788}
789
790/*
791 * Lock two thread queues using their address to maintain lock order.
792 */
793static void
794tdq_lock_pair(struct tdq *one, struct tdq *two)
795{
796	if (one < two) {
797		TDQ_LOCK(one);
798		TDQ_LOCK_FLAGS(two, MTX_DUPOK);
799	} else {
800		TDQ_LOCK(two);
801		TDQ_LOCK_FLAGS(one, MTX_DUPOK);
802	}
803}
804
805/*
806 * Unlock two thread queues.  Order is not important here.
807 */
808static void
809tdq_unlock_pair(struct tdq *one, struct tdq *two)
810{
811	TDQ_UNLOCK(one);
812	TDQ_UNLOCK(two);
813}
814
815/*
816 * Transfer load between two imbalanced thread queues.
817 */
818static int
819sched_balance_pair(struct tdq *high, struct tdq *low)
820{
821	int transferable;
822	int high_load;
823	int low_load;
824	int moved;
825	int move;
826	int diff;
827	int i;
828
829	tdq_lock_pair(high, low);
830	transferable = high->tdq_transferable;
831	high_load = high->tdq_load;
832	low_load = low->tdq_load;
833	moved = 0;
834	/*
835	 * Determine what the imbalance is and then adjust that to how many
836	 * threads we actually have to give up (transferable).
837	 */
838	if (transferable != 0) {
839		diff = high_load - low_load;
840		move = diff / 2;
841		if (diff & 0x1)
842			move++;
843		move = min(move, transferable);
844		for (i = 0; i < move; i++)
845			moved += tdq_move(high, low);
846		/*
847		 * IPI the target cpu to force it to reschedule with the new
848		 * workload.
849		 */
850		ipi_cpu(TDQ_ID(low), IPI_PREEMPT);
851	}
852	tdq_unlock_pair(high, low);
853	return (moved);
854}
855
856/*
857 * Move a thread from one thread queue to another.
858 */
859static int
860tdq_move(struct tdq *from, struct tdq *to)
861{
862	struct td_sched *ts;
863	struct thread *td;
864	struct tdq *tdq;
865	int cpu;
866
867	TDQ_LOCK_ASSERT(from, MA_OWNED);
868	TDQ_LOCK_ASSERT(to, MA_OWNED);
869
870	tdq = from;
871	cpu = TDQ_ID(to);
872	td = tdq_steal(tdq, cpu);
873	if (td == NULL)
874		return (0);
875	ts = td->td_sched;
876	/*
877	 * Although the run queue is locked the thread may be blocked.  Lock
878	 * it to clear this and acquire the run-queue lock.
879	 */
880	thread_lock(td);
881	/* Drop recursive lock on from acquired via thread_lock(). */
882	TDQ_UNLOCK(from);
883	sched_rem(td);
884	ts->ts_cpu = cpu;
885	td->td_lock = TDQ_LOCKPTR(to);
886	tdq_add(to, td, SRQ_YIELDING);
887	return (1);
888}
889
890/*
891 * This tdq has idled.  Try to steal a thread from another cpu and switch
892 * to it.
893 */
894static int
895tdq_idled(struct tdq *tdq)
896{
897	struct cpu_group *cg;
898	struct tdq *steal;
899	cpuset_t mask;
900	int thresh;
901	int cpu;
902
903	if (smp_started == 0 || steal_idle == 0)
904		return (1);
905	CPU_FILL(&mask);
906	CPU_CLR(PCPU_GET(cpuid), &mask);
907	/* We don't want to be preempted while we're iterating. */
908	spinlock_enter();
909	for (cg = tdq->tdq_cg; cg != NULL; ) {
910		if ((cg->cg_flags & CG_FLAG_THREAD) == 0)
911			thresh = steal_thresh;
912		else
913			thresh = 1;
914		cpu = sched_highest(cg, mask, thresh);
915		if (cpu == -1) {
916			cg = cg->cg_parent;
917			continue;
918		}
919		steal = TDQ_CPU(cpu);
920		CPU_CLR(cpu, &mask);
921		tdq_lock_pair(tdq, steal);
922		if (steal->tdq_load < thresh || steal->tdq_transferable == 0) {
923			tdq_unlock_pair(tdq, steal);
924			continue;
925		}
926		/*
927		 * If a thread was added while interrupts were disabled don't
928		 * steal one here.  If we fail to acquire one due to affinity
929		 * restrictions loop again with this cpu removed from the
930		 * set.
931		 */
932		if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) {
933			tdq_unlock_pair(tdq, steal);
934			continue;
935		}
936		spinlock_exit();
937		TDQ_UNLOCK(steal);
938		mi_switch(SW_VOL | SWT_IDLE, NULL);
939		thread_unlock(curthread);
940
941		return (0);
942	}
943	spinlock_exit();
944	return (1);
945}
946
947/*
948 * Notify a remote cpu of new work.  Sends an IPI if criteria are met.
949 */
950static void
951tdq_notify(struct tdq *tdq, struct thread *td)
952{
953	struct thread *ctd;
954	int pri;
955	int cpu;
956
957	if (tdq->tdq_ipipending)
958		return;
959	cpu = td->td_sched->ts_cpu;
960	pri = td->td_priority;
961	ctd = pcpu_find(cpu)->pc_curthread;
962	if (!sched_shouldpreempt(pri, ctd->td_priority, 1))
963		return;
964	if (TD_IS_IDLETHREAD(ctd)) {
965		/*
966		 * If the MD code has an idle wakeup routine try that before
967		 * falling back to IPI.
968		 */
969		if (cpu_idle_wakeup(cpu))
970			return;
971	}
972	tdq->tdq_ipipending = 1;
973	ipi_cpu(cpu, IPI_PREEMPT);
974}
975
976/*
977 * Steals load from a timeshare queue.  Honors the rotating queue head
978 * index.
979 */
980static struct thread *
981runq_steal_from(struct runq *rq, int cpu, u_char start)
982{
983	struct rqbits *rqb;
984	struct rqhead *rqh;
985	struct thread *td;
986	int first;
987	int bit;
988	int pri;
989	int i;
990
991	rqb = &rq->rq_status;
992	bit = start & (RQB_BPW -1);
993	pri = 0;
994	first = 0;
995again:
996	for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) {
997		if (rqb->rqb_bits[i] == 0)
998			continue;
999		if (bit != 0) {
1000			for (pri = bit; pri < RQB_BPW; pri++)
1001				if (rqb->rqb_bits[i] & (1ul << pri))
1002					break;
1003			if (pri >= RQB_BPW)
1004				continue;
1005		} else
1006			pri = RQB_FFS(rqb->rqb_bits[i]);
1007		pri += (i << RQB_L2BPW);
1008		rqh = &rq->rq_queues[pri];
1009		TAILQ_FOREACH(td, rqh, td_runq) {
1010			if (first && THREAD_CAN_MIGRATE(td) &&
1011			    THREAD_CAN_SCHED(td, cpu))
1012				return (td);
1013			first = 1;
1014		}
1015	}
1016	if (start != 0) {
1017		start = 0;
1018		goto again;
1019	}
1020
1021	return (NULL);
1022}
1023
1024/*
1025 * Steals load from a standard linear queue.
1026 */
1027static struct thread *
1028runq_steal(struct runq *rq, int cpu)
1029{
1030	struct rqhead *rqh;
1031	struct rqbits *rqb;
1032	struct thread *td;
1033	int word;
1034	int bit;
1035
1036	rqb = &rq->rq_status;
1037	for (word = 0; word < RQB_LEN; word++) {
1038		if (rqb->rqb_bits[word] == 0)
1039			continue;
1040		for (bit = 0; bit < RQB_BPW; bit++) {
1041			if ((rqb->rqb_bits[word] & (1ul << bit)) == 0)
1042				continue;
1043			rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)];
1044			TAILQ_FOREACH(td, rqh, td_runq)
1045				if (THREAD_CAN_MIGRATE(td) &&
1046				    THREAD_CAN_SCHED(td, cpu))
1047					return (td);
1048		}
1049	}
1050	return (NULL);
1051}
1052
1053/*
1054 * Attempt to steal a thread in priority order from a thread queue.
1055 */
1056static struct thread *
1057tdq_steal(struct tdq *tdq, int cpu)
1058{
1059	struct thread *td;
1060
1061	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1062	if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL)
1063		return (td);
1064	if ((td = runq_steal_from(&tdq->tdq_timeshare,
1065	    cpu, tdq->tdq_ridx)) != NULL)
1066		return (td);
1067	return (runq_steal(&tdq->tdq_idle, cpu));
1068}
1069
1070/*
1071 * Sets the thread lock and ts_cpu to match the requested cpu.  Unlocks the
1072 * current lock and returns with the assigned queue locked.
1073 */
1074static inline struct tdq *
1075sched_setcpu(struct thread *td, int cpu, int flags)
1076{
1077
1078	struct tdq *tdq;
1079
1080	THREAD_LOCK_ASSERT(td, MA_OWNED);
1081	tdq = TDQ_CPU(cpu);
1082	td->td_sched->ts_cpu = cpu;
1083	/*
1084	 * If the lock matches just return the queue.
1085	 */
1086	if (td->td_lock == TDQ_LOCKPTR(tdq))
1087		return (tdq);
1088#ifdef notyet
1089	/*
1090	 * If the thread isn't running its lockptr is a
1091	 * turnstile or a sleepqueue.  We can just lock_set without
1092	 * blocking.
1093	 */
1094	if (TD_CAN_RUN(td)) {
1095		TDQ_LOCK(tdq);
1096		thread_lock_set(td, TDQ_LOCKPTR(tdq));
1097		return (tdq);
1098	}
1099#endif
1100	/*
1101	 * The hard case, migration, we need to block the thread first to
1102	 * prevent order reversals with other cpus locks.
1103	 */
1104	spinlock_enter();
1105	thread_lock_block(td);
1106	TDQ_LOCK(tdq);
1107	thread_lock_unblock(td, TDQ_LOCKPTR(tdq));
1108	spinlock_exit();
1109	return (tdq);
1110}
1111
1112SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding");
1113SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity");
1114SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity");
1115SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load");
1116SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu");
1117SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration");
1118
1119static int
1120sched_pickcpu(struct thread *td, int flags)
1121{
1122	struct cpu_group *cg;
1123	struct td_sched *ts;
1124	struct tdq *tdq;
1125	cpuset_t mask;
1126	int self;
1127	int pri;
1128	int cpu;
1129
1130	self = PCPU_GET(cpuid);
1131	ts = td->td_sched;
1132	if (smp_started == 0)
1133		return (self);
1134	/*
1135	 * Don't migrate a running thread from sched_switch().
1136	 */
1137	if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td))
1138		return (ts->ts_cpu);
1139	/*
1140	 * Prefer to run interrupt threads on the processors that generate
1141	 * the interrupt.
1142	 */
1143	if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) &&
1144	    curthread->td_intr_nesting_level && ts->ts_cpu != self) {
1145		SCHED_STAT_INC(pickcpu_intrbind);
1146		ts->ts_cpu = self;
1147	}
1148	/*
1149	 * If the thread can run on the last cpu and the affinity has not
1150	 * expired or it is idle run it there.
1151	 */
1152	pri = td->td_priority;
1153	tdq = TDQ_CPU(ts->ts_cpu);
1154	if (THREAD_CAN_SCHED(td, ts->ts_cpu)) {
1155		if (tdq->tdq_lowpri > PRI_MIN_IDLE) {
1156			SCHED_STAT_INC(pickcpu_idle_affinity);
1157			return (ts->ts_cpu);
1158		}
1159		if (SCHED_AFFINITY(ts, CG_SHARE_L2) && tdq->tdq_lowpri > pri) {
1160			SCHED_STAT_INC(pickcpu_affinity);
1161			return (ts->ts_cpu);
1162		}
1163	}
1164	/*
1165	 * Search for the highest level in the tree that still has affinity.
1166	 */
1167	cg = NULL;
1168	for (cg = tdq->tdq_cg; cg != NULL; cg = cg->cg_parent)
1169		if (SCHED_AFFINITY(ts, cg->cg_level))
1170			break;
1171	cpu = -1;
1172	mask = td->td_cpuset->cs_mask;
1173	if (cg)
1174		cpu = sched_lowest(cg, mask, pri);
1175	if (cpu == -1)
1176		cpu = sched_lowest(cpu_top, mask, -1);
1177	/*
1178	 * Compare the lowest loaded cpu to current cpu.
1179	 */
1180	if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri &&
1181	    TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE) {
1182		SCHED_STAT_INC(pickcpu_local);
1183		cpu = self;
1184	} else
1185		SCHED_STAT_INC(pickcpu_lowest);
1186	if (cpu != ts->ts_cpu)
1187		SCHED_STAT_INC(pickcpu_migration);
1188	KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu."));
1189	return (cpu);
1190}
1191#endif
1192
1193/*
1194 * Pick the highest priority task we have and return it.
1195 */
1196static struct thread *
1197tdq_choose(struct tdq *tdq)
1198{
1199	struct thread *td;
1200
1201	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1202	td = runq_choose(&tdq->tdq_realtime);
1203	if (td != NULL)
1204		return (td);
1205	td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx);
1206	if (td != NULL) {
1207		KASSERT(td->td_priority >= PRI_MIN_TIMESHARE,
1208		    ("tdq_choose: Invalid priority on timeshare queue %d",
1209		    td->td_priority));
1210		return (td);
1211	}
1212	td = runq_choose(&tdq->tdq_idle);
1213	if (td != NULL) {
1214		KASSERT(td->td_priority >= PRI_MIN_IDLE,
1215		    ("tdq_choose: Invalid priority on idle queue %d",
1216		    td->td_priority));
1217		return (td);
1218	}
1219
1220	return (NULL);
1221}
1222
1223/*
1224 * Initialize a thread queue.
1225 */
1226static void
1227tdq_setup(struct tdq *tdq)
1228{
1229
1230	if (bootverbose)
1231		printf("ULE: setup cpu %d\n", TDQ_ID(tdq));
1232	runq_init(&tdq->tdq_realtime);
1233	runq_init(&tdq->tdq_timeshare);
1234	runq_init(&tdq->tdq_idle);
1235	snprintf(tdq->tdq_name, sizeof(tdq->tdq_name),
1236	    "sched lock %d", (int)TDQ_ID(tdq));
1237	mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock",
1238	    MTX_SPIN | MTX_RECURSE);
1239#ifdef KTR
1240	snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname),
1241	    "CPU %d load", (int)TDQ_ID(tdq));
1242#endif
1243}
1244
1245#ifdef SMP
1246static void
1247sched_setup_smp(void)
1248{
1249	struct tdq *tdq;
1250	int i;
1251
1252	cpu_top = smp_topo();
1253	CPU_FOREACH(i) {
1254		tdq = TDQ_CPU(i);
1255		tdq_setup(tdq);
1256		tdq->tdq_cg = smp_topo_find(cpu_top, i);
1257		if (tdq->tdq_cg == NULL)
1258			panic("Can't find cpu group for %d\n", i);
1259	}
1260	balance_tdq = TDQ_SELF();
1261	sched_balance();
1262}
1263#endif
1264
1265/*
1266 * Setup the thread queues and initialize the topology based on MD
1267 * information.
1268 */
1269static void
1270sched_setup(void *dummy)
1271{
1272	struct tdq *tdq;
1273
1274	tdq = TDQ_SELF();
1275#ifdef SMP
1276	sched_setup_smp();
1277#else
1278	tdq_setup(tdq);
1279#endif
1280	/*
1281	 * To avoid divide-by-zero, we set realstathz a dummy value
1282	 * in case which sched_clock() called before sched_initticks().
1283	 */
1284	realstathz = hz;
1285	sched_slice = (realstathz/10);	/* ~100ms */
1286	tickincr = 1 << SCHED_TICK_SHIFT;
1287
1288	/* Add thread0's load since it's running. */
1289	TDQ_LOCK(tdq);
1290	thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF());
1291	tdq_load_add(tdq, &thread0);
1292	tdq->tdq_lowpri = thread0.td_priority;
1293	TDQ_UNLOCK(tdq);
1294}
1295
1296/*
1297 * This routine determines the tickincr after stathz and hz are setup.
1298 */
1299/* ARGSUSED */
1300static void
1301sched_initticks(void *dummy)
1302{
1303	int incr;
1304
1305	realstathz = stathz ? stathz : hz;
1306	sched_slice = (realstathz/10);	/* ~100ms */
1307
1308	/*
1309	 * tickincr is shifted out by 10 to avoid rounding errors due to
1310	 * hz not being evenly divisible by stathz on all platforms.
1311	 */
1312	incr = (hz << SCHED_TICK_SHIFT) / realstathz;
1313	/*
1314	 * This does not work for values of stathz that are more than
1315	 * 1 << SCHED_TICK_SHIFT * hz.  In practice this does not happen.
1316	 */
1317	if (incr == 0)
1318		incr = 1;
1319	tickincr = incr;
1320#ifdef SMP
1321	/*
1322	 * Set the default balance interval now that we know
1323	 * what realstathz is.
1324	 */
1325	balance_interval = realstathz;
1326	/*
1327	 * Set steal thresh to roughly log2(mp_ncpu) but no greater than 4.
1328	 * This prevents excess thrashing on large machines and excess idle
1329	 * on smaller machines.
1330	 */
1331	steal_thresh = min(fls(mp_ncpus) - 1, 3);
1332	affinity = SCHED_AFFINITY_DEFAULT;
1333#endif
1334}
1335
1336
1337/*
1338 * This is the core of the interactivity algorithm.  Determines a score based
1339 * on past behavior.  It is the ratio of sleep time to run time scaled to
1340 * a [0, 100] integer.  This is the voluntary sleep time of a process, which
1341 * differs from the cpu usage because it does not account for time spent
1342 * waiting on a run-queue.  Would be prettier if we had floating point.
1343 */
1344static int
1345sched_interact_score(struct thread *td)
1346{
1347	struct td_sched *ts;
1348	int div;
1349
1350	ts = td->td_sched;
1351	/*
1352	 * The score is only needed if this is likely to be an interactive
1353	 * task.  Don't go through the expense of computing it if there's
1354	 * no chance.
1355	 */
1356	if (sched_interact <= SCHED_INTERACT_HALF &&
1357		ts->ts_runtime >= ts->ts_slptime)
1358			return (SCHED_INTERACT_HALF);
1359
1360	if (ts->ts_runtime > ts->ts_slptime) {
1361		div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF);
1362		return (SCHED_INTERACT_HALF +
1363		    (SCHED_INTERACT_HALF - (ts->ts_slptime / div)));
1364	}
1365	if (ts->ts_slptime > ts->ts_runtime) {
1366		div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF);
1367		return (ts->ts_runtime / div);
1368	}
1369	/* runtime == slptime */
1370	if (ts->ts_runtime)
1371		return (SCHED_INTERACT_HALF);
1372
1373	/*
1374	 * This can happen if slptime and runtime are 0.
1375	 */
1376	return (0);
1377
1378}
1379
1380/*
1381 * Scale the scheduling priority according to the "interactivity" of this
1382 * process.
1383 */
1384static void
1385sched_priority(struct thread *td)
1386{
1387	int score;
1388	int pri;
1389
1390	if (td->td_pri_class != PRI_TIMESHARE)
1391		return;
1392	/*
1393	 * If the score is interactive we place the thread in the realtime
1394	 * queue with a priority that is less than kernel and interrupt
1395	 * priorities.  These threads are not subject to nice restrictions.
1396	 *
1397	 * Scores greater than this are placed on the normal timeshare queue
1398	 * where the priority is partially decided by the most recent cpu
1399	 * utilization and the rest is decided by nice value.
1400	 *
1401	 * The nice value of the process has a linear effect on the calculated
1402	 * score.  Negative nice values make it easier for a thread to be
1403	 * considered interactive.
1404	 */
1405	score = imax(0, sched_interact_score(td) + td->td_proc->p_nice);
1406	if (score < sched_interact) {
1407		pri = PRI_MIN_REALTIME;
1408		pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME) / sched_interact)
1409		    * score;
1410		KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME,
1411		    ("sched_priority: invalid interactive priority %d score %d",
1412		    pri, score));
1413	} else {
1414		pri = SCHED_PRI_MIN;
1415		if (td->td_sched->ts_ticks)
1416			pri += SCHED_PRI_TICKS(td->td_sched);
1417		pri += SCHED_PRI_NICE(td->td_proc->p_nice);
1418		KASSERT(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE,
1419		    ("sched_priority: invalid priority %d: nice %d, "
1420		    "ticks %d ftick %d ltick %d tick pri %d",
1421		    pri, td->td_proc->p_nice, td->td_sched->ts_ticks,
1422		    td->td_sched->ts_ftick, td->td_sched->ts_ltick,
1423		    SCHED_PRI_TICKS(td->td_sched)));
1424	}
1425	sched_user_prio(td, pri);
1426
1427	return;
1428}
1429
1430/*
1431 * This routine enforces a maximum limit on the amount of scheduling history
1432 * kept.  It is called after either the slptime or runtime is adjusted.  This
1433 * function is ugly due to integer math.
1434 */
1435static void
1436sched_interact_update(struct thread *td)
1437{
1438	struct td_sched *ts;
1439	u_int sum;
1440
1441	ts = td->td_sched;
1442	sum = ts->ts_runtime + ts->ts_slptime;
1443	if (sum < SCHED_SLP_RUN_MAX)
1444		return;
1445	/*
1446	 * This only happens from two places:
1447	 * 1) We have added an unusual amount of run time from fork_exit.
1448	 * 2) We have added an unusual amount of sleep time from sched_sleep().
1449	 */
1450	if (sum > SCHED_SLP_RUN_MAX * 2) {
1451		if (ts->ts_runtime > ts->ts_slptime) {
1452			ts->ts_runtime = SCHED_SLP_RUN_MAX;
1453			ts->ts_slptime = 1;
1454		} else {
1455			ts->ts_slptime = SCHED_SLP_RUN_MAX;
1456			ts->ts_runtime = 1;
1457		}
1458		return;
1459	}
1460	/*
1461	 * If we have exceeded by more than 1/5th then the algorithm below
1462	 * will not bring us back into range.  Dividing by two here forces
1463	 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX]
1464	 */
1465	if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) {
1466		ts->ts_runtime /= 2;
1467		ts->ts_slptime /= 2;
1468		return;
1469	}
1470	ts->ts_runtime = (ts->ts_runtime / 5) * 4;
1471	ts->ts_slptime = (ts->ts_slptime / 5) * 4;
1472}
1473
1474/*
1475 * Scale back the interactivity history when a child thread is created.  The
1476 * history is inherited from the parent but the thread may behave totally
1477 * differently.  For example, a shell spawning a compiler process.  We want
1478 * to learn that the compiler is behaving badly very quickly.
1479 */
1480static void
1481sched_interact_fork(struct thread *td)
1482{
1483	int ratio;
1484	int sum;
1485
1486	sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime;
1487	if (sum > SCHED_SLP_RUN_FORK) {
1488		ratio = sum / SCHED_SLP_RUN_FORK;
1489		td->td_sched->ts_runtime /= ratio;
1490		td->td_sched->ts_slptime /= ratio;
1491	}
1492}
1493
1494/*
1495 * Called from proc0_init() to setup the scheduler fields.
1496 */
1497void
1498schedinit(void)
1499{
1500
1501	/*
1502	 * Set up the scheduler specific parts of proc0.
1503	 */
1504	proc0.p_sched = NULL; /* XXX */
1505	thread0.td_sched = &td_sched0;
1506	td_sched0.ts_ltick = ticks;
1507	td_sched0.ts_ftick = ticks;
1508	td_sched0.ts_slice = sched_slice;
1509}
1510
1511/*
1512 * This is only somewhat accurate since given many processes of the same
1513 * priority they will switch when their slices run out, which will be
1514 * at most sched_slice stathz ticks.
1515 */
1516int
1517sched_rr_interval(void)
1518{
1519
1520	/* Convert sched_slice to hz */
1521	return (hz/(realstathz/sched_slice));
1522}
1523
1524/*
1525 * Update the percent cpu tracking information when it is requested or
1526 * the total history exceeds the maximum.  We keep a sliding history of
1527 * tick counts that slowly decays.  This is less precise than the 4BSD
1528 * mechanism since it happens with less regular and frequent events.
1529 */
1530static void
1531sched_pctcpu_update(struct td_sched *ts)
1532{
1533
1534	if (ts->ts_ticks == 0)
1535		return;
1536	if (ticks - (hz / 10) < ts->ts_ltick &&
1537	    SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX)
1538		return;
1539	/*
1540	 * Adjust counters and watermark for pctcpu calc.
1541	 */
1542	if (ts->ts_ltick > ticks - SCHED_TICK_TARG)
1543		ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) *
1544			    SCHED_TICK_TARG;
1545	else
1546		ts->ts_ticks = 0;
1547	ts->ts_ltick = ticks;
1548	ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG;
1549}
1550
1551/*
1552 * Adjust the priority of a thread.  Move it to the appropriate run-queue
1553 * if necessary.  This is the back-end for several priority related
1554 * functions.
1555 */
1556static void
1557sched_thread_priority(struct thread *td, u_char prio)
1558{
1559	struct td_sched *ts;
1560	struct tdq *tdq;
1561	int oldpri;
1562
1563	KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio",
1564	    "prio:%d", td->td_priority, "new prio:%d", prio,
1565	    KTR_ATTR_LINKED, sched_tdname(curthread));
1566	if (td != curthread && prio > td->td_priority) {
1567		KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread),
1568		    "lend prio", "prio:%d", td->td_priority, "new prio:%d",
1569		    prio, KTR_ATTR_LINKED, sched_tdname(td));
1570	}
1571	ts = td->td_sched;
1572	THREAD_LOCK_ASSERT(td, MA_OWNED);
1573	if (td->td_priority == prio)
1574		return;
1575	/*
1576	 * If the priority has been elevated due to priority
1577	 * propagation, we may have to move ourselves to a new
1578	 * queue.  This could be optimized to not re-add in some
1579	 * cases.
1580	 */
1581	if (TD_ON_RUNQ(td) && prio < td->td_priority) {
1582		sched_rem(td);
1583		td->td_priority = prio;
1584		sched_add(td, SRQ_BORROWING);
1585		return;
1586	}
1587	/*
1588	 * If the thread is currently running we may have to adjust the lowpri
1589	 * information so other cpus are aware of our current priority.
1590	 */
1591	if (TD_IS_RUNNING(td)) {
1592		tdq = TDQ_CPU(ts->ts_cpu);
1593		oldpri = td->td_priority;
1594		td->td_priority = prio;
1595		if (prio < tdq->tdq_lowpri)
1596			tdq->tdq_lowpri = prio;
1597		else if (tdq->tdq_lowpri == oldpri)
1598			tdq_setlowpri(tdq, td);
1599		return;
1600	}
1601	td->td_priority = prio;
1602}
1603
1604/*
1605 * Update a thread's priority when it is lent another thread's
1606 * priority.
1607 */
1608void
1609sched_lend_prio(struct thread *td, u_char prio)
1610{
1611
1612	td->td_flags |= TDF_BORROWING;
1613	sched_thread_priority(td, prio);
1614}
1615
1616/*
1617 * Restore a thread's priority when priority propagation is
1618 * over.  The prio argument is the minimum priority the thread
1619 * needs to have to satisfy other possible priority lending
1620 * requests.  If the thread's regular priority is less
1621 * important than prio, the thread will keep a priority boost
1622 * of prio.
1623 */
1624void
1625sched_unlend_prio(struct thread *td, u_char prio)
1626{
1627	u_char base_pri;
1628
1629	if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
1630	    td->td_base_pri <= PRI_MAX_TIMESHARE)
1631		base_pri = td->td_user_pri;
1632	else
1633		base_pri = td->td_base_pri;
1634	if (prio >= base_pri) {
1635		td->td_flags &= ~TDF_BORROWING;
1636		sched_thread_priority(td, base_pri);
1637	} else
1638		sched_lend_prio(td, prio);
1639}
1640
1641/*
1642 * Standard entry for setting the priority to an absolute value.
1643 */
1644void
1645sched_prio(struct thread *td, u_char prio)
1646{
1647	u_char oldprio;
1648
1649	/* First, update the base priority. */
1650	td->td_base_pri = prio;
1651
1652	/*
1653	 * If the thread is borrowing another thread's priority, don't
1654	 * ever lower the priority.
1655	 */
1656	if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
1657		return;
1658
1659	/* Change the real priority. */
1660	oldprio = td->td_priority;
1661	sched_thread_priority(td, prio);
1662
1663	/*
1664	 * If the thread is on a turnstile, then let the turnstile update
1665	 * its state.
1666	 */
1667	if (TD_ON_LOCK(td) && oldprio != prio)
1668		turnstile_adjust(td, oldprio);
1669}
1670
1671/*
1672 * Set the base user priority, does not effect current running priority.
1673 */
1674void
1675sched_user_prio(struct thread *td, u_char prio)
1676{
1677	u_char oldprio;
1678
1679	td->td_base_user_pri = prio;
1680	if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio)
1681                return;
1682	oldprio = td->td_user_pri;
1683	td->td_user_pri = prio;
1684}
1685
1686void
1687sched_lend_user_prio(struct thread *td, u_char prio)
1688{
1689	u_char oldprio;
1690
1691	THREAD_LOCK_ASSERT(td, MA_OWNED);
1692	td->td_flags |= TDF_UBORROWING;
1693	oldprio = td->td_user_pri;
1694	td->td_user_pri = prio;
1695}
1696
1697void
1698sched_unlend_user_prio(struct thread *td, u_char prio)
1699{
1700	u_char base_pri;
1701
1702	THREAD_LOCK_ASSERT(td, MA_OWNED);
1703	base_pri = td->td_base_user_pri;
1704	if (prio >= base_pri) {
1705		td->td_flags &= ~TDF_UBORROWING;
1706		sched_user_prio(td, base_pri);
1707	} else {
1708		sched_lend_user_prio(td, prio);
1709	}
1710}
1711
1712/*
1713 * Handle migration from sched_switch().  This happens only for
1714 * cpu binding.
1715 */
1716static struct mtx *
1717sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags)
1718{
1719	struct tdq *tdn;
1720
1721	tdn = TDQ_CPU(td->td_sched->ts_cpu);
1722#ifdef SMP
1723	tdq_load_rem(tdq, td);
1724	/*
1725	 * Do the lock dance required to avoid LOR.  We grab an extra
1726	 * spinlock nesting to prevent preemption while we're
1727	 * not holding either run-queue lock.
1728	 */
1729	spinlock_enter();
1730	thread_lock_block(td);	/* This releases the lock on tdq. */
1731
1732	/*
1733	 * Acquire both run-queue locks before placing the thread on the new
1734	 * run-queue to avoid deadlocks created by placing a thread with a
1735	 * blocked lock on the run-queue of a remote processor.  The deadlock
1736	 * occurs when a third processor attempts to lock the two queues in
1737	 * question while the target processor is spinning with its own
1738	 * run-queue lock held while waiting for the blocked lock to clear.
1739	 */
1740	tdq_lock_pair(tdn, tdq);
1741	tdq_add(tdn, td, flags);
1742	tdq_notify(tdn, td);
1743	TDQ_UNLOCK(tdn);
1744	spinlock_exit();
1745#endif
1746	return (TDQ_LOCKPTR(tdn));
1747}
1748
1749/*
1750 * Variadic version of thread_lock_unblock() that does not assume td_lock
1751 * is blocked.
1752 */
1753static inline void
1754thread_unblock_switch(struct thread *td, struct mtx *mtx)
1755{
1756	atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock,
1757	    (uintptr_t)mtx);
1758}
1759
1760/*
1761 * Switch threads.  This function has to handle threads coming in while
1762 * blocked for some reason, running, or idle.  It also must deal with
1763 * migrating a thread from one queue to another as running threads may
1764 * be assigned elsewhere via binding.
1765 */
1766void
1767sched_switch(struct thread *td, struct thread *newtd, int flags)
1768{
1769	struct tdq *tdq;
1770	struct td_sched *ts;
1771	struct mtx *mtx;
1772	int srqflag;
1773	int cpuid;
1774
1775	THREAD_LOCK_ASSERT(td, MA_OWNED);
1776	KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument"));
1777
1778	cpuid = PCPU_GET(cpuid);
1779	tdq = TDQ_CPU(cpuid);
1780	ts = td->td_sched;
1781	mtx = td->td_lock;
1782	ts->ts_rltick = ticks;
1783	td->td_lastcpu = td->td_oncpu;
1784	td->td_oncpu = NOCPU;
1785	td->td_flags &= ~TDF_NEEDRESCHED;
1786	td->td_owepreempt = 0;
1787	tdq->tdq_switchcnt++;
1788	/*
1789	 * The lock pointer in an idle thread should never change.  Reset it
1790	 * to CAN_RUN as well.
1791	 */
1792	if (TD_IS_IDLETHREAD(td)) {
1793		MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1794		TD_SET_CAN_RUN(td);
1795	} else if (TD_IS_RUNNING(td)) {
1796		MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1797		srqflag = (flags & SW_PREEMPT) ?
1798		    SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
1799		    SRQ_OURSELF|SRQ_YIELDING;
1800		if (ts->ts_cpu == cpuid)
1801			tdq_runq_add(tdq, td, srqflag);
1802		else
1803			mtx = sched_switch_migrate(tdq, td, srqflag);
1804	} else {
1805		/* This thread must be going to sleep. */
1806		TDQ_LOCK(tdq);
1807		mtx = thread_lock_block(td);
1808		tdq_load_rem(tdq, td);
1809	}
1810	/*
1811	 * We enter here with the thread blocked and assigned to the
1812	 * appropriate cpu run-queue or sleep-queue and with the current
1813	 * thread-queue locked.
1814	 */
1815	TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
1816	newtd = choosethread();
1817	/*
1818	 * Call the MD code to switch contexts if necessary.
1819	 */
1820	if (td != newtd) {
1821#ifdef	HWPMC_HOOKS
1822		if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1823			PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
1824#endif
1825		lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
1826		TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
1827
1828#ifdef KDTRACE_HOOKS
1829		/*
1830		 * If DTrace has set the active vtime enum to anything
1831		 * other than INACTIVE (0), then it should have set the
1832		 * function to call.
1833		 */
1834		if (dtrace_vtime_active)
1835			(*dtrace_vtime_switch_func)(newtd);
1836#endif
1837
1838		cpu_switch(td, newtd, mtx);
1839		/*
1840		 * We may return from cpu_switch on a different cpu.  However,
1841		 * we always return with td_lock pointing to the current cpu's
1842		 * run queue lock.
1843		 */
1844		cpuid = PCPU_GET(cpuid);
1845		tdq = TDQ_CPU(cpuid);
1846		lock_profile_obtain_lock_success(
1847		    &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
1848#ifdef	HWPMC_HOOKS
1849		if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1850			PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
1851#endif
1852	} else
1853		thread_unblock_switch(td, mtx);
1854	/*
1855	 * Assert that all went well and return.
1856	 */
1857	TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED);
1858	MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1859	td->td_oncpu = cpuid;
1860}
1861
1862/*
1863 * Adjust thread priorities as a result of a nice request.
1864 */
1865void
1866sched_nice(struct proc *p, int nice)
1867{
1868	struct thread *td;
1869
1870	PROC_LOCK_ASSERT(p, MA_OWNED);
1871
1872	p->p_nice = nice;
1873	FOREACH_THREAD_IN_PROC(p, td) {
1874		thread_lock(td);
1875		sched_priority(td);
1876		sched_prio(td, td->td_base_user_pri);
1877		thread_unlock(td);
1878	}
1879}
1880
1881/*
1882 * Record the sleep time for the interactivity scorer.
1883 */
1884void
1885sched_sleep(struct thread *td, int prio)
1886{
1887
1888	THREAD_LOCK_ASSERT(td, MA_OWNED);
1889
1890	td->td_slptick = ticks;
1891	if (TD_IS_SUSPENDED(td) || prio >= PSOCK)
1892		td->td_flags |= TDF_CANSWAP;
1893	if (static_boost == 1 && prio)
1894		sched_prio(td, prio);
1895	else if (static_boost && td->td_priority > static_boost)
1896		sched_prio(td, static_boost);
1897}
1898
1899/*
1900 * Schedule a thread to resume execution and record how long it voluntarily
1901 * slept.  We also update the pctcpu, interactivity, and priority.
1902 */
1903void
1904sched_wakeup(struct thread *td)
1905{
1906	struct td_sched *ts;
1907	int slptick;
1908
1909	THREAD_LOCK_ASSERT(td, MA_OWNED);
1910	ts = td->td_sched;
1911	td->td_flags &= ~TDF_CANSWAP;
1912	/*
1913	 * If we slept for more than a tick update our interactivity and
1914	 * priority.
1915	 */
1916	slptick = td->td_slptick;
1917	td->td_slptick = 0;
1918	if (slptick && slptick != ticks) {
1919		u_int hzticks;
1920
1921		hzticks = (ticks - slptick) << SCHED_TICK_SHIFT;
1922		ts->ts_slptime += hzticks;
1923		sched_interact_update(td);
1924		sched_pctcpu_update(ts);
1925	}
1926	/* Reset the slice value after we sleep. */
1927	ts->ts_slice = sched_slice;
1928	sched_add(td, SRQ_BORING);
1929}
1930
1931/*
1932 * Penalize the parent for creating a new child and initialize the child's
1933 * priority.
1934 */
1935void
1936sched_fork(struct thread *td, struct thread *child)
1937{
1938	THREAD_LOCK_ASSERT(td, MA_OWNED);
1939	sched_fork_thread(td, child);
1940	/*
1941	 * Penalize the parent and child for forking.
1942	 */
1943	sched_interact_fork(child);
1944	sched_priority(child);
1945	td->td_sched->ts_runtime += tickincr;
1946	sched_interact_update(td);
1947	sched_priority(td);
1948}
1949
1950/*
1951 * Fork a new thread, may be within the same process.
1952 */
1953void
1954sched_fork_thread(struct thread *td, struct thread *child)
1955{
1956	struct td_sched *ts;
1957	struct td_sched *ts2;
1958
1959	THREAD_LOCK_ASSERT(td, MA_OWNED);
1960	/*
1961	 * Initialize child.
1962	 */
1963	ts = td->td_sched;
1964	ts2 = child->td_sched;
1965	child->td_lock = TDQ_LOCKPTR(TDQ_SELF());
1966	child->td_cpuset = cpuset_ref(td->td_cpuset);
1967	ts2->ts_cpu = ts->ts_cpu;
1968	ts2->ts_flags = 0;
1969	/*
1970	 * Grab our parents cpu estimation information and priority.
1971	 */
1972	ts2->ts_ticks = ts->ts_ticks;
1973	ts2->ts_ltick = ts->ts_ltick;
1974	ts2->ts_incrtick = ts->ts_incrtick;
1975	ts2->ts_ftick = ts->ts_ftick;
1976	child->td_user_pri = td->td_user_pri;
1977	child->td_base_user_pri = td->td_base_user_pri;
1978	/*
1979	 * And update interactivity score.
1980	 */
1981	ts2->ts_slptime = ts->ts_slptime;
1982	ts2->ts_runtime = ts->ts_runtime;
1983	ts2->ts_slice = 1;	/* Attempt to quickly learn interactivity. */
1984#ifdef KTR
1985	bzero(ts2->ts_name, sizeof(ts2->ts_name));
1986#endif
1987}
1988
1989/*
1990 * Adjust the priority class of a thread.
1991 */
1992void
1993sched_class(struct thread *td, int class)
1994{
1995
1996	THREAD_LOCK_ASSERT(td, MA_OWNED);
1997	if (td->td_pri_class == class)
1998		return;
1999	td->td_pri_class = class;
2000}
2001
2002/*
2003 * Return some of the child's priority and interactivity to the parent.
2004 */
2005void
2006sched_exit(struct proc *p, struct thread *child)
2007{
2008	struct thread *td;
2009
2010	KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit",
2011	    "prio:td", child->td_priority);
2012	PROC_LOCK_ASSERT(p, MA_OWNED);
2013	td = FIRST_THREAD_IN_PROC(p);
2014	sched_exit_thread(td, child);
2015}
2016
2017/*
2018 * Penalize another thread for the time spent on this one.  This helps to
2019 * worsen the priority and interactivity of processes which schedule batch
2020 * jobs such as make.  This has little effect on the make process itself but
2021 * causes new processes spawned by it to receive worse scores immediately.
2022 */
2023void
2024sched_exit_thread(struct thread *td, struct thread *child)
2025{
2026
2027	KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit",
2028	    "prio:td", child->td_priority);
2029	/*
2030	 * Give the child's runtime to the parent without returning the
2031	 * sleep time as a penalty to the parent.  This causes shells that
2032	 * launch expensive things to mark their children as expensive.
2033	 */
2034	thread_lock(td);
2035	td->td_sched->ts_runtime += child->td_sched->ts_runtime;
2036	sched_interact_update(td);
2037	sched_priority(td);
2038	thread_unlock(td);
2039}
2040
2041void
2042sched_preempt(struct thread *td)
2043{
2044	struct tdq *tdq;
2045
2046	thread_lock(td);
2047	tdq = TDQ_SELF();
2048	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2049	tdq->tdq_ipipending = 0;
2050	if (td->td_priority > tdq->tdq_lowpri) {
2051		int flags;
2052
2053		flags = SW_INVOL | SW_PREEMPT;
2054		if (td->td_critnest > 1)
2055			td->td_owepreempt = 1;
2056		else if (TD_IS_IDLETHREAD(td))
2057			mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL);
2058		else
2059			mi_switch(flags | SWT_REMOTEPREEMPT, NULL);
2060	}
2061	thread_unlock(td);
2062}
2063
2064/*
2065 * Fix priorities on return to user-space.  Priorities may be elevated due
2066 * to static priorities in msleep() or similar.
2067 */
2068void
2069sched_userret(struct thread *td)
2070{
2071	/*
2072	 * XXX we cheat slightly on the locking here to avoid locking in
2073	 * the usual case.  Setting td_priority here is essentially an
2074	 * incomplete workaround for not setting it properly elsewhere.
2075	 * Now that some interrupt handlers are threads, not setting it
2076	 * properly elsewhere can clobber it in the window between setting
2077	 * it here and returning to user mode, so don't waste time setting
2078	 * it perfectly here.
2079	 */
2080	KASSERT((td->td_flags & TDF_BORROWING) == 0,
2081	    ("thread with borrowed priority returning to userland"));
2082	if (td->td_priority != td->td_user_pri) {
2083		thread_lock(td);
2084		td->td_priority = td->td_user_pri;
2085		td->td_base_pri = td->td_user_pri;
2086		tdq_setlowpri(TDQ_SELF(), td);
2087		thread_unlock(td);
2088        }
2089}
2090
2091/*
2092 * Handle a stathz tick.  This is really only relevant for timeshare
2093 * threads.
2094 */
2095void
2096sched_clock(struct thread *td)
2097{
2098	struct tdq *tdq;
2099	struct td_sched *ts;
2100
2101	THREAD_LOCK_ASSERT(td, MA_OWNED);
2102	tdq = TDQ_SELF();
2103#ifdef SMP
2104	/*
2105	 * We run the long term load balancer infrequently on the first cpu.
2106	 */
2107	if (balance_tdq == tdq) {
2108		if (balance_ticks && --balance_ticks == 0)
2109			sched_balance();
2110	}
2111#endif
2112	/*
2113	 * Save the old switch count so we have a record of the last ticks
2114	 * activity.   Initialize the new switch count based on our load.
2115	 * If there is some activity seed it to reflect that.
2116	 */
2117	tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt;
2118	tdq->tdq_switchcnt = tdq->tdq_load;
2119	/*
2120	 * Advance the insert index once for each tick to ensure that all
2121	 * threads get a chance to run.
2122	 */
2123	if (tdq->tdq_idx == tdq->tdq_ridx) {
2124		tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS;
2125		if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx]))
2126			tdq->tdq_ridx = tdq->tdq_idx;
2127	}
2128	ts = td->td_sched;
2129	if (td->td_pri_class & PRI_FIFO_BIT)
2130		return;
2131	if (td->td_pri_class == PRI_TIMESHARE) {
2132		/*
2133		 * We used a tick; charge it to the thread so
2134		 * that we can compute our interactivity.
2135		 */
2136		td->td_sched->ts_runtime += tickincr;
2137		sched_interact_update(td);
2138		sched_priority(td);
2139	}
2140	/*
2141	 * We used up one time slice.
2142	 */
2143	if (--ts->ts_slice > 0)
2144		return;
2145	/*
2146	 * We're out of time, force a requeue at userret().
2147	 */
2148	ts->ts_slice = sched_slice;
2149	td->td_flags |= TDF_NEEDRESCHED;
2150}
2151
2152/*
2153 * Called once per hz tick.  Used for cpu utilization information.  This
2154 * is easier than trying to scale based on stathz.
2155 */
2156void
2157sched_tick(void)
2158{
2159	struct td_sched *ts;
2160
2161	ts = curthread->td_sched;
2162	/*
2163	 * Ticks is updated asynchronously on a single cpu.  Check here to
2164	 * avoid incrementing ts_ticks multiple times in a single tick.
2165	 */
2166	if (ts->ts_incrtick == ticks)
2167		return;
2168	/* Adjust ticks for pctcpu */
2169	ts->ts_ticks += 1 << SCHED_TICK_SHIFT;
2170	ts->ts_ltick = ticks;
2171	ts->ts_incrtick = ticks;
2172	/*
2173	 * Update if we've exceeded our desired tick threshhold by over one
2174	 * second.
2175	 */
2176	if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick)
2177		sched_pctcpu_update(ts);
2178}
2179
2180/*
2181 * Return whether the current CPU has runnable tasks.  Used for in-kernel
2182 * cooperative idle threads.
2183 */
2184int
2185sched_runnable(void)
2186{
2187	struct tdq *tdq;
2188	int load;
2189
2190	load = 1;
2191
2192	tdq = TDQ_SELF();
2193	if ((curthread->td_flags & TDF_IDLETD) != 0) {
2194		if (tdq->tdq_load > 0)
2195			goto out;
2196	} else
2197		if (tdq->tdq_load - 1 > 0)
2198			goto out;
2199	load = 0;
2200out:
2201	return (load);
2202}
2203
2204/*
2205 * Choose the highest priority thread to run.  The thread is removed from
2206 * the run-queue while running however the load remains.  For SMP we set
2207 * the tdq in the global idle bitmask if it idles here.
2208 */
2209struct thread *
2210sched_choose(void)
2211{
2212	struct thread *td;
2213	struct tdq *tdq;
2214
2215	tdq = TDQ_SELF();
2216	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2217	td = tdq_choose(tdq);
2218	if (td) {
2219		td->td_sched->ts_ltick = ticks;
2220		tdq_runq_rem(tdq, td);
2221		tdq->tdq_lowpri = td->td_priority;
2222		return (td);
2223	}
2224	tdq->tdq_lowpri = PRI_MAX_IDLE;
2225	return (PCPU_GET(idlethread));
2226}
2227
2228/*
2229 * Set owepreempt if necessary.  Preemption never happens directly in ULE,
2230 * we always request it once we exit a critical section.
2231 */
2232static inline void
2233sched_setpreempt(struct thread *td)
2234{
2235	struct thread *ctd;
2236	int cpri;
2237	int pri;
2238
2239	THREAD_LOCK_ASSERT(curthread, MA_OWNED);
2240
2241	ctd = curthread;
2242	pri = td->td_priority;
2243	cpri = ctd->td_priority;
2244	if (pri < cpri)
2245		ctd->td_flags |= TDF_NEEDRESCHED;
2246	if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd))
2247		return;
2248	if (!sched_shouldpreempt(pri, cpri, 0))
2249		return;
2250	ctd->td_owepreempt = 1;
2251}
2252
2253/*
2254 * Add a thread to a thread queue.  Select the appropriate runq and add the
2255 * thread to it.  This is the internal function called when the tdq is
2256 * predetermined.
2257 */
2258void
2259tdq_add(struct tdq *tdq, struct thread *td, int flags)
2260{
2261
2262	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2263	KASSERT((td->td_inhibitors == 0),
2264	    ("sched_add: trying to run inhibited thread"));
2265	KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
2266	    ("sched_add: bad thread state"));
2267	KASSERT(td->td_flags & TDF_INMEM,
2268	    ("sched_add: thread swapped out"));
2269
2270	if (td->td_priority < tdq->tdq_lowpri)
2271		tdq->tdq_lowpri = td->td_priority;
2272	tdq_runq_add(tdq, td, flags);
2273	tdq_load_add(tdq, td);
2274}
2275
2276/*
2277 * Select the target thread queue and add a thread to it.  Request
2278 * preemption or IPI a remote processor if required.
2279 */
2280void
2281sched_add(struct thread *td, int flags)
2282{
2283	struct tdq *tdq;
2284#ifdef SMP
2285	int cpu;
2286#endif
2287
2288	KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
2289	    "prio:%d", td->td_priority, KTR_ATTR_LINKED,
2290	    sched_tdname(curthread));
2291	KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
2292	    KTR_ATTR_LINKED, sched_tdname(td));
2293	THREAD_LOCK_ASSERT(td, MA_OWNED);
2294	/*
2295	 * Recalculate the priority before we select the target cpu or
2296	 * run-queue.
2297	 */
2298	if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
2299		sched_priority(td);
2300#ifdef SMP
2301	/*
2302	 * Pick the destination cpu and if it isn't ours transfer to the
2303	 * target cpu.
2304	 */
2305	cpu = sched_pickcpu(td, flags);
2306	tdq = sched_setcpu(td, cpu, flags);
2307	tdq_add(tdq, td, flags);
2308	if (cpu != PCPU_GET(cpuid)) {
2309		tdq_notify(tdq, td);
2310		return;
2311	}
2312#else
2313	tdq = TDQ_SELF();
2314	TDQ_LOCK(tdq);
2315	/*
2316	 * Now that the thread is moving to the run-queue, set the lock
2317	 * to the scheduler's lock.
2318	 */
2319	thread_lock_set(td, TDQ_LOCKPTR(tdq));
2320	tdq_add(tdq, td, flags);
2321#endif
2322	if (!(flags & SRQ_YIELDING))
2323		sched_setpreempt(td);
2324}
2325
2326/*
2327 * Remove a thread from a run-queue without running it.  This is used
2328 * when we're stealing a thread from a remote queue.  Otherwise all threads
2329 * exit by calling sched_exit_thread() and sched_throw() themselves.
2330 */
2331void
2332sched_rem(struct thread *td)
2333{
2334	struct tdq *tdq;
2335
2336	KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem",
2337	    "prio:%d", td->td_priority);
2338	tdq = TDQ_CPU(td->td_sched->ts_cpu);
2339	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2340	MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2341	KASSERT(TD_ON_RUNQ(td),
2342	    ("sched_rem: thread not on run queue"));
2343	tdq_runq_rem(tdq, td);
2344	tdq_load_rem(tdq, td);
2345	TD_SET_CAN_RUN(td);
2346	if (td->td_priority == tdq->tdq_lowpri)
2347		tdq_setlowpri(tdq, NULL);
2348}
2349
2350/*
2351 * Fetch cpu utilization information.  Updates on demand.
2352 */
2353fixpt_t
2354sched_pctcpu(struct thread *td)
2355{
2356	fixpt_t pctcpu;
2357	struct td_sched *ts;
2358
2359	pctcpu = 0;
2360	ts = td->td_sched;
2361	if (ts == NULL)
2362		return (0);
2363
2364	THREAD_LOCK_ASSERT(td, MA_OWNED);
2365	if (ts->ts_ticks) {
2366		int rtick;
2367
2368		sched_pctcpu_update(ts);
2369		/* How many rtick per second ? */
2370		rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz);
2371		pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT;
2372	}
2373
2374	return (pctcpu);
2375}
2376
2377/*
2378 * Enforce affinity settings for a thread.  Called after adjustments to
2379 * cpumask.
2380 */
2381void
2382sched_affinity(struct thread *td)
2383{
2384#ifdef SMP
2385	struct td_sched *ts;
2386	int cpu;
2387
2388	THREAD_LOCK_ASSERT(td, MA_OWNED);
2389	ts = td->td_sched;
2390	if (THREAD_CAN_SCHED(td, ts->ts_cpu))
2391		return;
2392	if (TD_ON_RUNQ(td)) {
2393		sched_rem(td);
2394		sched_add(td, SRQ_BORING);
2395		return;
2396	}
2397	if (!TD_IS_RUNNING(td))
2398		return;
2399	td->td_flags |= TDF_NEEDRESCHED;
2400	if (!THREAD_CAN_MIGRATE(td))
2401		return;
2402	/*
2403	 * Assign the new cpu and force a switch before returning to
2404	 * userspace.  If the target thread is not running locally send
2405	 * an ipi to force the issue.
2406	 */
2407	cpu = ts->ts_cpu;
2408	ts->ts_cpu = sched_pickcpu(td, 0);
2409	if (cpu != PCPU_GET(cpuid))
2410		ipi_cpu(cpu, IPI_PREEMPT);
2411#endif
2412}
2413
2414/*
2415 * Bind a thread to a target cpu.
2416 */
2417void
2418sched_bind(struct thread *td, int cpu)
2419{
2420	struct td_sched *ts;
2421
2422	THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED);
2423	KASSERT(td == curthread, ("sched_bind: can only bind curthread"));
2424	ts = td->td_sched;
2425	if (ts->ts_flags & TSF_BOUND)
2426		sched_unbind(td);
2427	ts->ts_flags |= TSF_BOUND;
2428	sched_pin();
2429	if (PCPU_GET(cpuid) == cpu)
2430		return;
2431	ts->ts_cpu = cpu;
2432	/* When we return from mi_switch we'll be on the correct cpu. */
2433	mi_switch(SW_VOL, NULL);
2434}
2435
2436/*
2437 * Release a bound thread.
2438 */
2439void
2440sched_unbind(struct thread *td)
2441{
2442	struct td_sched *ts;
2443
2444	THREAD_LOCK_ASSERT(td, MA_OWNED);
2445	KASSERT(td == curthread, ("sched_unbind: can only bind curthread"));
2446	ts = td->td_sched;
2447	if ((ts->ts_flags & TSF_BOUND) == 0)
2448		return;
2449	ts->ts_flags &= ~TSF_BOUND;
2450	sched_unpin();
2451}
2452
2453int
2454sched_is_bound(struct thread *td)
2455{
2456	THREAD_LOCK_ASSERT(td, MA_OWNED);
2457	return (td->td_sched->ts_flags & TSF_BOUND);
2458}
2459
2460/*
2461 * Basic yield call.
2462 */
2463void
2464sched_relinquish(struct thread *td)
2465{
2466	thread_lock(td);
2467	mi_switch(SW_VOL | SWT_RELINQUISH, NULL);
2468	thread_unlock(td);
2469}
2470
2471/*
2472 * Return the total system load.
2473 */
2474int
2475sched_load(void)
2476{
2477#ifdef SMP
2478	int total;
2479	int i;
2480
2481	total = 0;
2482	CPU_FOREACH(i)
2483		total += TDQ_CPU(i)->tdq_sysload;
2484	return (total);
2485#else
2486	return (TDQ_SELF()->tdq_sysload);
2487#endif
2488}
2489
2490int
2491sched_sizeof_proc(void)
2492{
2493	return (sizeof(struct proc));
2494}
2495
2496int
2497sched_sizeof_thread(void)
2498{
2499	return (sizeof(struct thread) + sizeof(struct td_sched));
2500}
2501
2502#ifdef SMP
2503#define	TDQ_IDLESPIN(tdq)						\
2504    ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0)
2505#else
2506#define	TDQ_IDLESPIN(tdq)	1
2507#endif
2508
2509/*
2510 * The actual idle process.
2511 */
2512void
2513sched_idletd(void *dummy)
2514{
2515	struct thread *td;
2516	struct tdq *tdq;
2517	int switchcnt;
2518	int i;
2519
2520	mtx_assert(&Giant, MA_NOTOWNED);
2521	td = curthread;
2522	tdq = TDQ_SELF();
2523	for (;;) {
2524#ifdef SMP
2525		if (tdq_idled(tdq) == 0)
2526			continue;
2527#endif
2528		switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2529		/*
2530		 * If we're switching very frequently, spin while checking
2531		 * for load rather than entering a low power state that
2532		 * may require an IPI.  However, don't do any busy
2533		 * loops while on SMT machines as this simply steals
2534		 * cycles from cores doing useful work.
2535		 */
2536		if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) {
2537			for (i = 0; i < sched_idlespins; i++) {
2538				if (tdq->tdq_load)
2539					break;
2540				cpu_spinwait();
2541			}
2542		}
2543		switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2544		if (tdq->tdq_load == 0)
2545			cpu_idle(switchcnt > 1);
2546		if (tdq->tdq_load) {
2547			thread_lock(td);
2548			mi_switch(SW_VOL | SWT_IDLE, NULL);
2549			thread_unlock(td);
2550		}
2551	}
2552}
2553
2554/*
2555 * A CPU is entering for the first time or a thread is exiting.
2556 */
2557void
2558sched_throw(struct thread *td)
2559{
2560	struct thread *newtd;
2561	struct tdq *tdq;
2562
2563	tdq = TDQ_SELF();
2564	if (td == NULL) {
2565		/* Correct spinlock nesting and acquire the correct lock. */
2566		TDQ_LOCK(tdq);
2567		spinlock_exit();
2568	} else {
2569		MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2570		tdq_load_rem(tdq, td);
2571		lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
2572	}
2573	KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
2574	newtd = choosethread();
2575	TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
2576	PCPU_SET(switchtime, cpu_ticks());
2577	PCPU_SET(switchticks, ticks);
2578	cpu_throw(td, newtd);		/* doesn't return */
2579}
2580
2581/*
2582 * This is called from fork_exit().  Just acquire the correct locks and
2583 * let fork do the rest of the work.
2584 */
2585void
2586sched_fork_exit(struct thread *td)
2587{
2588	struct td_sched *ts;
2589	struct tdq *tdq;
2590	int cpuid;
2591
2592	/*
2593	 * Finish setting up thread glue so that it begins execution in a
2594	 * non-nested critical section with the scheduler lock held.
2595	 */
2596	cpuid = PCPU_GET(cpuid);
2597	tdq = TDQ_CPU(cpuid);
2598	ts = td->td_sched;
2599	if (TD_IS_IDLETHREAD(td))
2600		td->td_lock = TDQ_LOCKPTR(tdq);
2601	MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2602	td->td_oncpu = cpuid;
2603	TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
2604	lock_profile_obtain_lock_success(
2605	    &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
2606}
2607
2608/*
2609 * Create on first use to catch odd startup conditons.
2610 */
2611char *
2612sched_tdname(struct thread *td)
2613{
2614#ifdef KTR
2615	struct td_sched *ts;
2616
2617	ts = td->td_sched;
2618	if (ts->ts_name[0] == '\0')
2619		snprintf(ts->ts_name, sizeof(ts->ts_name),
2620		    "%s tid %d", td->td_name, td->td_tid);
2621	return (ts->ts_name);
2622#else
2623	return (td->td_name);
2624#endif
2625}
2626
2627#ifdef SMP
2628
2629/*
2630 * Build the CPU topology dump string. Is recursively called to collect
2631 * the topology tree.
2632 */
2633static int
2634sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg,
2635    int indent)
2636{
2637	int i, first;
2638
2639	sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent,
2640	    "", indent, cg->cg_level);
2641	sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"0x%x\">", indent, "",
2642	    cg->cg_count, cg->cg_mask);
2643	first = TRUE;
2644	for (i = 0; i < MAXCPU; i++) {
2645		if ((cg->cg_mask & (1 << i)) != 0) {
2646			if (!first)
2647				sbuf_printf(sb, ", ");
2648			else
2649				first = FALSE;
2650			sbuf_printf(sb, "%d", i);
2651		}
2652	}
2653	sbuf_printf(sb, "</cpu>\n");
2654
2655	if (cg->cg_flags != 0) {
2656		sbuf_printf(sb, "%*s <flags>", indent, "");
2657		if ((cg->cg_flags & CG_FLAG_HTT) != 0)
2658			sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>");
2659		if ((cg->cg_flags & CG_FLAG_THREAD) != 0)
2660			sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>");
2661		if ((cg->cg_flags & CG_FLAG_SMT) != 0)
2662			sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>");
2663		sbuf_printf(sb, "</flags>\n");
2664	}
2665
2666	if (cg->cg_children > 0) {
2667		sbuf_printf(sb, "%*s <children>\n", indent, "");
2668		for (i = 0; i < cg->cg_children; i++)
2669			sysctl_kern_sched_topology_spec_internal(sb,
2670			    &cg->cg_child[i], indent+2);
2671		sbuf_printf(sb, "%*s </children>\n", indent, "");
2672	}
2673	sbuf_printf(sb, "%*s</group>\n", indent, "");
2674	return (0);
2675}
2676
2677/*
2678 * Sysctl handler for retrieving topology dump. It's a wrapper for
2679 * the recursive sysctl_kern_smp_topology_spec_internal().
2680 */
2681static int
2682sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS)
2683{
2684	struct sbuf *topo;
2685	int err;
2686
2687	KASSERT(cpu_top != NULL, ("cpu_top isn't initialized"));
2688
2689	topo = sbuf_new(NULL, NULL, 500, SBUF_AUTOEXTEND);
2690	if (topo == NULL)
2691		return (ENOMEM);
2692
2693	sbuf_printf(topo, "<groups>\n");
2694	err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1);
2695	sbuf_printf(topo, "</groups>\n");
2696
2697	if (err == 0) {
2698		sbuf_finish(topo);
2699		err = SYSCTL_OUT(req, sbuf_data(topo), sbuf_len(topo));
2700	}
2701	sbuf_delete(topo);
2702	return (err);
2703}
2704#endif
2705
2706SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler");
2707SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0,
2708    "Scheduler name");
2709SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
2710    "Slice size for timeshare threads");
2711SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0,
2712     "Interactivity score threshold");
2713SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh,
2714     0,"Min priority for preemption, lower priorities have greater precedence");
2715SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost,
2716     0,"Controls whether static kernel priorities are assigned to sleeping threads.");
2717SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins,
2718     0,"Number of times idle will spin waiting for new work.");
2719SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW, &sched_idlespinthresh,
2720     0,"Threshold before we will permit idle spinning.");
2721#ifdef SMP
2722SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0,
2723    "Number of hz ticks to keep thread affinity for");
2724SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0,
2725    "Enables the long-term load balancer");
2726SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW,
2727    &balance_interval, 0,
2728    "Average frequency in stathz ticks to run the long-term balancer");
2729SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0,
2730    "Steals work from another hyper-threaded core on idle");
2731SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0,
2732    "Attempts to steal work from other cores before idling");
2733SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0,
2734    "Minimum load on remote cpu before we'll steal");
2735
2736/* Retrieve SMP topology */
2737SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING |
2738    CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A",
2739    "XML dump of detected CPU topology");
2740#endif
2741
2742/* ps compat.  All cpu percentages from ULE are weighted. */
2743static int ccpu = 0;
2744SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
2745