sched_ule.c revision 217237
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 217237 2011-01-10 20:48:10Z 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 + 1)
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:	Threshold 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 = 16;
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	volatile int	tdq_cpu_idle;		/* cpu_idle() is active. */
212	int		tdq_sysload;		/* For loadavg, !ITHD load. */
213	int		tdq_transferable;	/* Transferable thread count. */
214	short		tdq_switchcnt;		/* Switches this tick. */
215	short		tdq_oldswitchcnt;	/* Switches last tick. */
216	u_char		tdq_lowpri;		/* Lowest priority thread. */
217	u_char		tdq_ipipending;		/* IPI pending. */
218	u_char		tdq_idx;		/* Current insert index. */
219	u_char		tdq_ridx;		/* Current removal index. */
220	struct runq	tdq_realtime;		/* real-time run queue. */
221	struct runq	tdq_timeshare;		/* timeshare run queue. */
222	struct runq	tdq_idle;		/* Queue of IDLE threads. */
223	char		tdq_name[TDQ_NAME_LEN];
224#ifdef KTR
225	char		tdq_loadname[TDQ_LOADNAME_LEN];
226#endif
227} __aligned(64);
228
229/* Idle thread states and config. */
230#define	TDQ_RUNNING	1
231#define	TDQ_IDLE	2
232
233#ifdef SMP
234struct cpu_group *cpu_top;		/* CPU topology */
235
236#define	SCHED_AFFINITY_DEFAULT	(max(1, hz / 1000))
237#define	SCHED_AFFINITY(ts, t)	((ts)->ts_rltick > ticks - ((t) * affinity))
238
239/*
240 * Run-time tunables.
241 */
242static int rebalance = 1;
243static int balance_interval = 128;	/* Default set in sched_initticks(). */
244static int affinity;
245static int steal_htt = 1;
246static int steal_idle = 1;
247static int steal_thresh = 2;
248
249/*
250 * One thread queue per processor.
251 */
252static struct tdq	tdq_cpu[MAXCPU];
253static struct tdq	*balance_tdq;
254static int balance_ticks;
255
256#define	TDQ_SELF()	(&tdq_cpu[PCPU_GET(cpuid)])
257#define	TDQ_CPU(x)	(&tdq_cpu[(x)])
258#define	TDQ_ID(x)	((int)((x) - tdq_cpu))
259#else	/* !SMP */
260static struct tdq	tdq_cpu;
261
262#define	TDQ_ID(x)	(0)
263#define	TDQ_SELF()	(&tdq_cpu)
264#define	TDQ_CPU(x)	(&tdq_cpu)
265#endif
266
267#define	TDQ_LOCK_ASSERT(t, type)	mtx_assert(TDQ_LOCKPTR((t)), (type))
268#define	TDQ_LOCK(t)		mtx_lock_spin(TDQ_LOCKPTR((t)))
269#define	TDQ_LOCK_FLAGS(t, f)	mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f))
270#define	TDQ_UNLOCK(t)		mtx_unlock_spin(TDQ_LOCKPTR((t)))
271#define	TDQ_LOCKPTR(t)		(&(t)->tdq_lock)
272
273static void sched_priority(struct thread *);
274static void sched_thread_priority(struct thread *, u_char);
275static int sched_interact_score(struct thread *);
276static void sched_interact_update(struct thread *);
277static void sched_interact_fork(struct thread *);
278static void sched_pctcpu_update(struct td_sched *);
279
280/* Operations on per processor queues */
281static struct thread *tdq_choose(struct tdq *);
282static void tdq_setup(struct tdq *);
283static void tdq_load_add(struct tdq *, struct thread *);
284static void tdq_load_rem(struct tdq *, struct thread *);
285static __inline void tdq_runq_add(struct tdq *, struct thread *, int);
286static __inline void tdq_runq_rem(struct tdq *, struct thread *);
287static inline int sched_shouldpreempt(int, int, int);
288void tdq_print(int cpu);
289static void runq_print(struct runq *rq);
290static void tdq_add(struct tdq *, struct thread *, int);
291#ifdef SMP
292static int tdq_move(struct tdq *, struct tdq *);
293static int tdq_idled(struct tdq *);
294static void tdq_notify(struct tdq *, struct thread *);
295static struct thread *tdq_steal(struct tdq *, int);
296static struct thread *runq_steal(struct runq *, int);
297static int sched_pickcpu(struct thread *, int);
298static void sched_balance(void);
299static int sched_balance_pair(struct tdq *, struct tdq *);
300static inline struct tdq *sched_setcpu(struct thread *, int, int);
301static inline void thread_unblock_switch(struct thread *, struct mtx *);
302static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int);
303static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS);
304static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb,
305    struct cpu_group *cg, int indent);
306#endif
307
308static void sched_setup(void *dummy);
309SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
310
311static void sched_initticks(void *dummy);
312SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks,
313    NULL);
314
315/*
316 * Print the threads waiting on a run-queue.
317 */
318static void
319runq_print(struct runq *rq)
320{
321	struct rqhead *rqh;
322	struct thread *td;
323	int pri;
324	int j;
325	int i;
326
327	for (i = 0; i < RQB_LEN; i++) {
328		printf("\t\trunq bits %d 0x%zx\n",
329		    i, rq->rq_status.rqb_bits[i]);
330		for (j = 0; j < RQB_BPW; j++)
331			if (rq->rq_status.rqb_bits[i] & (1ul << j)) {
332				pri = j + (i << RQB_L2BPW);
333				rqh = &rq->rq_queues[pri];
334				TAILQ_FOREACH(td, rqh, td_runq) {
335					printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n",
336					    td, td->td_name, td->td_priority,
337					    td->td_rqindex, pri);
338				}
339			}
340	}
341}
342
343/*
344 * Print the status of a per-cpu thread queue.  Should be a ddb show cmd.
345 */
346void
347tdq_print(int cpu)
348{
349	struct tdq *tdq;
350
351	tdq = TDQ_CPU(cpu);
352
353	printf("tdq %d:\n", TDQ_ID(tdq));
354	printf("\tlock            %p\n", TDQ_LOCKPTR(tdq));
355	printf("\tLock name:      %s\n", tdq->tdq_name);
356	printf("\tload:           %d\n", tdq->tdq_load);
357	printf("\tswitch cnt:     %d\n", tdq->tdq_switchcnt);
358	printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt);
359	printf("\ttimeshare idx:  %d\n", tdq->tdq_idx);
360	printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx);
361	printf("\tload transferable: %d\n", tdq->tdq_transferable);
362	printf("\tlowest priority:   %d\n", tdq->tdq_lowpri);
363	printf("\trealtime runq:\n");
364	runq_print(&tdq->tdq_realtime);
365	printf("\ttimeshare runq:\n");
366	runq_print(&tdq->tdq_timeshare);
367	printf("\tidle runq:\n");
368	runq_print(&tdq->tdq_idle);
369}
370
371static inline int
372sched_shouldpreempt(int pri, int cpri, int remote)
373{
374	/*
375	 * If the new priority is not better than the current priority there is
376	 * nothing to do.
377	 */
378	if (pri >= cpri)
379		return (0);
380	/*
381	 * Always preempt idle.
382	 */
383	if (cpri >= PRI_MIN_IDLE)
384		return (1);
385	/*
386	 * If preemption is disabled don't preempt others.
387	 */
388	if (preempt_thresh == 0)
389		return (0);
390	/*
391	 * Preempt if we exceed the threshold.
392	 */
393	if (pri <= preempt_thresh)
394		return (1);
395	/*
396	 * If we're realtime or better and there is timeshare or worse running
397	 * preempt only remote processors.
398	 */
399	if (remote && pri <= PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME)
400		return (1);
401	return (0);
402}
403
404#define	TS_RQ_PPQ	(((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS)
405/*
406 * Add a thread to the actual run-queue.  Keeps transferable counts up to
407 * date with what is actually on the run-queue.  Selects the correct
408 * queue position for timeshare threads.
409 */
410static __inline void
411tdq_runq_add(struct tdq *tdq, struct thread *td, int flags)
412{
413	struct td_sched *ts;
414	u_char pri;
415
416	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
417	THREAD_LOCK_ASSERT(td, MA_OWNED);
418
419	pri = td->td_priority;
420	ts = td->td_sched;
421	TD_SET_RUNQ(td);
422	if (THREAD_CAN_MIGRATE(td)) {
423		tdq->tdq_transferable++;
424		ts->ts_flags |= TSF_XFERABLE;
425	}
426	if (pri <= PRI_MAX_REALTIME) {
427		ts->ts_runq = &tdq->tdq_realtime;
428	} else if (pri <= PRI_MAX_TIMESHARE) {
429		ts->ts_runq = &tdq->tdq_timeshare;
430		KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE,
431			("Invalid priority %d on timeshare runq", pri));
432		/*
433		 * This queue contains only priorities between MIN and MAX
434		 * realtime.  Use the whole queue to represent these values.
435		 */
436		if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) {
437			pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ;
438			pri = (pri + tdq->tdq_idx) % RQ_NQS;
439			/*
440			 * This effectively shortens the queue by one so we
441			 * can have a one slot difference between idx and
442			 * ridx while we wait for threads to drain.
443			 */
444			if (tdq->tdq_ridx != tdq->tdq_idx &&
445			    pri == tdq->tdq_ridx)
446				pri = (unsigned char)(pri - 1) % RQ_NQS;
447		} else
448			pri = tdq->tdq_ridx;
449		runq_add_pri(ts->ts_runq, td, pri, flags);
450		return;
451	} else
452		ts->ts_runq = &tdq->tdq_idle;
453	runq_add(ts->ts_runq, td, flags);
454}
455
456/*
457 * Remove a thread from a run-queue.  This typically happens when a thread
458 * is selected to run.  Running threads are not on the queue and the
459 * transferable count does not reflect them.
460 */
461static __inline void
462tdq_runq_rem(struct tdq *tdq, struct thread *td)
463{
464	struct td_sched *ts;
465
466	ts = td->td_sched;
467	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
468	KASSERT(ts->ts_runq != NULL,
469	    ("tdq_runq_remove: thread %p null ts_runq", td));
470	if (ts->ts_flags & TSF_XFERABLE) {
471		tdq->tdq_transferable--;
472		ts->ts_flags &= ~TSF_XFERABLE;
473	}
474	if (ts->ts_runq == &tdq->tdq_timeshare) {
475		if (tdq->tdq_idx != tdq->tdq_ridx)
476			runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx);
477		else
478			runq_remove_idx(ts->ts_runq, td, NULL);
479	} else
480		runq_remove(ts->ts_runq, td);
481}
482
483/*
484 * Load is maintained for all threads RUNNING and ON_RUNQ.  Add the load
485 * for this thread to the referenced thread queue.
486 */
487static void
488tdq_load_add(struct tdq *tdq, struct thread *td)
489{
490
491	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
492	THREAD_LOCK_ASSERT(td, MA_OWNED);
493
494	tdq->tdq_load++;
495	if ((td->td_flags & TDF_NOLOAD) == 0)
496		tdq->tdq_sysload++;
497	KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
498}
499
500/*
501 * Remove the load from a thread that is transitioning to a sleep state or
502 * exiting.
503 */
504static void
505tdq_load_rem(struct tdq *tdq, struct thread *td)
506{
507
508	THREAD_LOCK_ASSERT(td, MA_OWNED);
509	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
510	KASSERT(tdq->tdq_load != 0,
511	    ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq)));
512
513	tdq->tdq_load--;
514	if ((td->td_flags & TDF_NOLOAD) == 0)
515		tdq->tdq_sysload--;
516	KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
517}
518
519/*
520 * Set lowpri to its exact value by searching the run-queue and
521 * evaluating curthread.  curthread may be passed as an optimization.
522 */
523static void
524tdq_setlowpri(struct tdq *tdq, struct thread *ctd)
525{
526	struct thread *td;
527
528	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
529	if (ctd == NULL)
530		ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread;
531	td = tdq_choose(tdq);
532	if (td == NULL || td->td_priority > ctd->td_priority)
533		tdq->tdq_lowpri = ctd->td_priority;
534	else
535		tdq->tdq_lowpri = td->td_priority;
536}
537
538#ifdef SMP
539struct cpu_search {
540	cpuset_t cs_mask;
541	u_int	cs_load;
542	u_int	cs_cpu;
543	int	cs_limit;	/* Min priority for low min load for high. */
544};
545
546#define	CPU_SEARCH_LOWEST	0x1
547#define	CPU_SEARCH_HIGHEST	0x2
548#define	CPU_SEARCH_BOTH		(CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST)
549
550#define	CPUSET_FOREACH(cpu, mask)				\
551	for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++)		\
552		if ((mask) & 1 << (cpu))
553
554static __inline int cpu_search(struct cpu_group *cg, struct cpu_search *low,
555    struct cpu_search *high, const int match);
556int cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low);
557int cpu_search_highest(struct cpu_group *cg, struct cpu_search *high);
558int cpu_search_both(struct cpu_group *cg, struct cpu_search *low,
559    struct cpu_search *high);
560
561/*
562 * This routine compares according to the match argument and should be
563 * reduced in actual instantiations via constant propagation and dead code
564 * elimination.
565 */
566static __inline int
567cpu_compare(int cpu, struct cpu_search *low, struct cpu_search *high,
568    const int match)
569{
570	struct tdq *tdq;
571
572	tdq = TDQ_CPU(cpu);
573	if (match & CPU_SEARCH_LOWEST)
574		if (CPU_ISSET(cpu, &low->cs_mask) &&
575		    tdq->tdq_load < low->cs_load &&
576		    tdq->tdq_lowpri > low->cs_limit) {
577			low->cs_cpu = cpu;
578			low->cs_load = tdq->tdq_load;
579		}
580	if (match & CPU_SEARCH_HIGHEST)
581		if (CPU_ISSET(cpu, &high->cs_mask) &&
582		    tdq->tdq_load >= high->cs_limit &&
583		    tdq->tdq_load > high->cs_load &&
584		    tdq->tdq_transferable) {
585			high->cs_cpu = cpu;
586			high->cs_load = tdq->tdq_load;
587		}
588	return (tdq->tdq_load);
589}
590
591/*
592 * Search the tree of cpu_groups for the lowest or highest loaded cpu
593 * according to the match argument.  This routine actually compares the
594 * load on all paths through the tree and finds the least loaded cpu on
595 * the least loaded path, which may differ from the least loaded cpu in
596 * the system.  This balances work among caches and busses.
597 *
598 * This inline is instantiated in three forms below using constants for the
599 * match argument.  It is reduced to the minimum set for each case.  It is
600 * also recursive to the depth of the tree.
601 */
602static __inline int
603cpu_search(struct cpu_group *cg, struct cpu_search *low,
604    struct cpu_search *high, const int match)
605{
606	int total;
607
608	total = 0;
609	if (cg->cg_children) {
610		struct cpu_search lgroup;
611		struct cpu_search hgroup;
612		struct cpu_group *child;
613		u_int lload;
614		int hload;
615		int load;
616		int i;
617
618		lload = -1;
619		hload = -1;
620		for (i = 0; i < cg->cg_children; i++) {
621			child = &cg->cg_child[i];
622			if (match & CPU_SEARCH_LOWEST) {
623				lgroup = *low;
624				lgroup.cs_load = -1;
625			}
626			if (match & CPU_SEARCH_HIGHEST) {
627				hgroup = *high;
628				lgroup.cs_load = 0;
629			}
630			switch (match) {
631			case CPU_SEARCH_LOWEST:
632				load = cpu_search_lowest(child, &lgroup);
633				break;
634			case CPU_SEARCH_HIGHEST:
635				load = cpu_search_highest(child, &hgroup);
636				break;
637			case CPU_SEARCH_BOTH:
638				load = cpu_search_both(child, &lgroup, &hgroup);
639				break;
640			}
641			total += load;
642			if (match & CPU_SEARCH_LOWEST)
643				if (load < lload || low->cs_cpu == -1) {
644					*low = lgroup;
645					lload = load;
646				}
647			if (match & CPU_SEARCH_HIGHEST)
648				if (load > hload || high->cs_cpu == -1) {
649					hload = load;
650					*high = hgroup;
651				}
652		}
653	} else {
654		int cpu;
655
656		CPUSET_FOREACH(cpu, cg->cg_mask)
657			total += cpu_compare(cpu, low, high, match);
658	}
659	return (total);
660}
661
662/*
663 * cpu_search instantiations must pass constants to maintain the inline
664 * optimization.
665 */
666int
667cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low)
668{
669	return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST);
670}
671
672int
673cpu_search_highest(struct cpu_group *cg, struct cpu_search *high)
674{
675	return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST);
676}
677
678int
679cpu_search_both(struct cpu_group *cg, struct cpu_search *low,
680    struct cpu_search *high)
681{
682	return cpu_search(cg, low, high, CPU_SEARCH_BOTH);
683}
684
685/*
686 * Find the cpu with the least load via the least loaded path that has a
687 * lowpri greater than pri  pri.  A pri of -1 indicates any priority is
688 * acceptable.
689 */
690static inline int
691sched_lowest(struct cpu_group *cg, cpuset_t mask, int pri)
692{
693	struct cpu_search low;
694
695	low.cs_cpu = -1;
696	low.cs_load = -1;
697	low.cs_mask = mask;
698	low.cs_limit = pri;
699	cpu_search_lowest(cg, &low);
700	return low.cs_cpu;
701}
702
703/*
704 * Find the cpu with the highest load via the highest loaded path.
705 */
706static inline int
707sched_highest(struct cpu_group *cg, cpuset_t mask, int minload)
708{
709	struct cpu_search high;
710
711	high.cs_cpu = -1;
712	high.cs_load = 0;
713	high.cs_mask = mask;
714	high.cs_limit = minload;
715	cpu_search_highest(cg, &high);
716	return high.cs_cpu;
717}
718
719/*
720 * Simultaneously find the highest and lowest loaded cpu reachable via
721 * cg.
722 */
723static inline void
724sched_both(struct cpu_group *cg, cpuset_t mask, int *lowcpu, int *highcpu)
725{
726	struct cpu_search high;
727	struct cpu_search low;
728
729	low.cs_cpu = -1;
730	low.cs_limit = -1;
731	low.cs_load = -1;
732	low.cs_mask = mask;
733	high.cs_load = 0;
734	high.cs_cpu = -1;
735	high.cs_limit = -1;
736	high.cs_mask = mask;
737	cpu_search_both(cg, &low, &high);
738	*lowcpu = low.cs_cpu;
739	*highcpu = high.cs_cpu;
740	return;
741}
742
743static void
744sched_balance_group(struct cpu_group *cg)
745{
746	cpuset_t mask;
747	int high;
748	int low;
749	int i;
750
751	CPU_FILL(&mask);
752	for (;;) {
753		sched_both(cg, mask, &low, &high);
754		if (low == high || low == -1 || high == -1)
755			break;
756		if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low)))
757			break;
758		/*
759		 * If we failed to move any threads determine which cpu
760		 * to kick out of the set and try again.
761	 	 */
762		if (TDQ_CPU(high)->tdq_transferable == 0)
763			CPU_CLR(high, &mask);
764		else
765			CPU_CLR(low, &mask);
766	}
767
768	for (i = 0; i < cg->cg_children; i++)
769		sched_balance_group(&cg->cg_child[i]);
770}
771
772static void
773sched_balance(void)
774{
775	struct tdq *tdq;
776
777	/*
778	 * Select a random time between .5 * balance_interval and
779	 * 1.5 * balance_interval.
780	 */
781	balance_ticks = max(balance_interval / 2, 1);
782	balance_ticks += random() % balance_interval;
783	if (smp_started == 0 || rebalance == 0)
784		return;
785	tdq = TDQ_SELF();
786	TDQ_UNLOCK(tdq);
787	sched_balance_group(cpu_top);
788	TDQ_LOCK(tdq);
789}
790
791/*
792 * Lock two thread queues using their address to maintain lock order.
793 */
794static void
795tdq_lock_pair(struct tdq *one, struct tdq *two)
796{
797	if (one < two) {
798		TDQ_LOCK(one);
799		TDQ_LOCK_FLAGS(two, MTX_DUPOK);
800	} else {
801		TDQ_LOCK(two);
802		TDQ_LOCK_FLAGS(one, MTX_DUPOK);
803	}
804}
805
806/*
807 * Unlock two thread queues.  Order is not important here.
808 */
809static void
810tdq_unlock_pair(struct tdq *one, struct tdq *two)
811{
812	TDQ_UNLOCK(one);
813	TDQ_UNLOCK(two);
814}
815
816/*
817 * Transfer load between two imbalanced thread queues.
818 */
819static int
820sched_balance_pair(struct tdq *high, struct tdq *low)
821{
822	int transferable;
823	int high_load;
824	int low_load;
825	int moved;
826	int move;
827	int diff;
828	int i;
829
830	tdq_lock_pair(high, low);
831	transferable = high->tdq_transferable;
832	high_load = high->tdq_load;
833	low_load = low->tdq_load;
834	moved = 0;
835	/*
836	 * Determine what the imbalance is and then adjust that to how many
837	 * threads we actually have to give up (transferable).
838	 */
839	if (transferable != 0) {
840		diff = high_load - low_load;
841		move = diff / 2;
842		if (diff & 0x1)
843			move++;
844		move = min(move, transferable);
845		for (i = 0; i < move; i++)
846			moved += tdq_move(high, low);
847		/*
848		 * IPI the target cpu to force it to reschedule with the new
849		 * workload.
850		 */
851		ipi_cpu(TDQ_ID(low), IPI_PREEMPT);
852	}
853	tdq_unlock_pair(high, low);
854	return (moved);
855}
856
857/*
858 * Move a thread from one thread queue to another.
859 */
860static int
861tdq_move(struct tdq *from, struct tdq *to)
862{
863	struct td_sched *ts;
864	struct thread *td;
865	struct tdq *tdq;
866	int cpu;
867
868	TDQ_LOCK_ASSERT(from, MA_OWNED);
869	TDQ_LOCK_ASSERT(to, MA_OWNED);
870
871	tdq = from;
872	cpu = TDQ_ID(to);
873	td = tdq_steal(tdq, cpu);
874	if (td == NULL)
875		return (0);
876	ts = td->td_sched;
877	/*
878	 * Although the run queue is locked the thread may be blocked.  Lock
879	 * it to clear this and acquire the run-queue lock.
880	 */
881	thread_lock(td);
882	/* Drop recursive lock on from acquired via thread_lock(). */
883	TDQ_UNLOCK(from);
884	sched_rem(td);
885	ts->ts_cpu = cpu;
886	td->td_lock = TDQ_LOCKPTR(to);
887	tdq_add(to, td, SRQ_YIELDING);
888	return (1);
889}
890
891/*
892 * This tdq has idled.  Try to steal a thread from another cpu and switch
893 * to it.
894 */
895static int
896tdq_idled(struct tdq *tdq)
897{
898	struct cpu_group *cg;
899	struct tdq *steal;
900	cpuset_t mask;
901	int thresh;
902	int cpu;
903
904	if (smp_started == 0 || steal_idle == 0)
905		return (1);
906	CPU_FILL(&mask);
907	CPU_CLR(PCPU_GET(cpuid), &mask);
908	/* We don't want to be preempted while we're iterating. */
909	spinlock_enter();
910	for (cg = tdq->tdq_cg; cg != NULL; ) {
911		if ((cg->cg_flags & CG_FLAG_THREAD) == 0)
912			thresh = steal_thresh;
913		else
914			thresh = 1;
915		cpu = sched_highest(cg, mask, thresh);
916		if (cpu == -1) {
917			cg = cg->cg_parent;
918			continue;
919		}
920		steal = TDQ_CPU(cpu);
921		CPU_CLR(cpu, &mask);
922		tdq_lock_pair(tdq, steal);
923		if (steal->tdq_load < thresh || steal->tdq_transferable == 0) {
924			tdq_unlock_pair(tdq, steal);
925			continue;
926		}
927		/*
928		 * If a thread was added while interrupts were disabled don't
929		 * steal one here.  If we fail to acquire one due to affinity
930		 * restrictions loop again with this cpu removed from the
931		 * set.
932		 */
933		if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) {
934			tdq_unlock_pair(tdq, steal);
935			continue;
936		}
937		spinlock_exit();
938		TDQ_UNLOCK(steal);
939		mi_switch(SW_VOL | SWT_IDLE, NULL);
940		thread_unlock(curthread);
941
942		return (0);
943	}
944	spinlock_exit();
945	return (1);
946}
947
948/*
949 * Notify a remote cpu of new work.  Sends an IPI if criteria are met.
950 */
951static void
952tdq_notify(struct tdq *tdq, struct thread *td)
953{
954	struct thread *ctd;
955	int pri;
956	int cpu;
957
958	if (tdq->tdq_ipipending)
959		return;
960	cpu = td->td_sched->ts_cpu;
961	pri = td->td_priority;
962	ctd = pcpu_find(cpu)->pc_curthread;
963	if (!sched_shouldpreempt(pri, ctd->td_priority, 1))
964		return;
965	if (TD_IS_IDLETHREAD(ctd)) {
966		/*
967		 * If the MD code has an idle wakeup routine try that before
968		 * falling back to IPI.
969		 */
970		if (!tdq->tdq_cpu_idle || cpu_idle_wakeup(cpu))
971			return;
972	}
973	tdq->tdq_ipipending = 1;
974	ipi_cpu(cpu, IPI_PREEMPT);
975}
976
977/*
978 * Steals load from a timeshare queue.  Honors the rotating queue head
979 * index.
980 */
981static struct thread *
982runq_steal_from(struct runq *rq, int cpu, u_char start)
983{
984	struct rqbits *rqb;
985	struct rqhead *rqh;
986	struct thread *td;
987	int first;
988	int bit;
989	int pri;
990	int i;
991
992	rqb = &rq->rq_status;
993	bit = start & (RQB_BPW -1);
994	pri = 0;
995	first = 0;
996again:
997	for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) {
998		if (rqb->rqb_bits[i] == 0)
999			continue;
1000		if (bit != 0) {
1001			for (pri = bit; pri < RQB_BPW; pri++)
1002				if (rqb->rqb_bits[i] & (1ul << pri))
1003					break;
1004			if (pri >= RQB_BPW)
1005				continue;
1006		} else
1007			pri = RQB_FFS(rqb->rqb_bits[i]);
1008		pri += (i << RQB_L2BPW);
1009		rqh = &rq->rq_queues[pri];
1010		TAILQ_FOREACH(td, rqh, td_runq) {
1011			if (first && THREAD_CAN_MIGRATE(td) &&
1012			    THREAD_CAN_SCHED(td, cpu))
1013				return (td);
1014			first = 1;
1015		}
1016	}
1017	if (start != 0) {
1018		start = 0;
1019		goto again;
1020	}
1021
1022	return (NULL);
1023}
1024
1025/*
1026 * Steals load from a standard linear queue.
1027 */
1028static struct thread *
1029runq_steal(struct runq *rq, int cpu)
1030{
1031	struct rqhead *rqh;
1032	struct rqbits *rqb;
1033	struct thread *td;
1034	int word;
1035	int bit;
1036
1037	rqb = &rq->rq_status;
1038	for (word = 0; word < RQB_LEN; word++) {
1039		if (rqb->rqb_bits[word] == 0)
1040			continue;
1041		for (bit = 0; bit < RQB_BPW; bit++) {
1042			if ((rqb->rqb_bits[word] & (1ul << bit)) == 0)
1043				continue;
1044			rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)];
1045			TAILQ_FOREACH(td, rqh, td_runq)
1046				if (THREAD_CAN_MIGRATE(td) &&
1047				    THREAD_CAN_SCHED(td, cpu))
1048					return (td);
1049		}
1050	}
1051	return (NULL);
1052}
1053
1054/*
1055 * Attempt to steal a thread in priority order from a thread queue.
1056 */
1057static struct thread *
1058tdq_steal(struct tdq *tdq, int cpu)
1059{
1060	struct thread *td;
1061
1062	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1063	if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL)
1064		return (td);
1065	if ((td = runq_steal_from(&tdq->tdq_timeshare,
1066	    cpu, tdq->tdq_ridx)) != NULL)
1067		return (td);
1068	return (runq_steal(&tdq->tdq_idle, cpu));
1069}
1070
1071/*
1072 * Sets the thread lock and ts_cpu to match the requested cpu.  Unlocks the
1073 * current lock and returns with the assigned queue locked.
1074 */
1075static inline struct tdq *
1076sched_setcpu(struct thread *td, int cpu, int flags)
1077{
1078
1079	struct tdq *tdq;
1080
1081	THREAD_LOCK_ASSERT(td, MA_OWNED);
1082	tdq = TDQ_CPU(cpu);
1083	td->td_sched->ts_cpu = cpu;
1084	/*
1085	 * If the lock matches just return the queue.
1086	 */
1087	if (td->td_lock == TDQ_LOCKPTR(tdq))
1088		return (tdq);
1089#ifdef notyet
1090	/*
1091	 * If the thread isn't running its lockptr is a
1092	 * turnstile or a sleepqueue.  We can just lock_set without
1093	 * blocking.
1094	 */
1095	if (TD_CAN_RUN(td)) {
1096		TDQ_LOCK(tdq);
1097		thread_lock_set(td, TDQ_LOCKPTR(tdq));
1098		return (tdq);
1099	}
1100#endif
1101	/*
1102	 * The hard case, migration, we need to block the thread first to
1103	 * prevent order reversals with other cpus locks.
1104	 */
1105	spinlock_enter();
1106	thread_lock_block(td);
1107	TDQ_LOCK(tdq);
1108	thread_lock_unblock(td, TDQ_LOCKPTR(tdq));
1109	spinlock_exit();
1110	return (tdq);
1111}
1112
1113SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding");
1114SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity");
1115SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity");
1116SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load");
1117SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu");
1118SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration");
1119
1120static int
1121sched_pickcpu(struct thread *td, int flags)
1122{
1123	struct cpu_group *cg;
1124	struct td_sched *ts;
1125	struct tdq *tdq;
1126	cpuset_t mask;
1127	int self;
1128	int pri;
1129	int cpu;
1130
1131	self = PCPU_GET(cpuid);
1132	ts = td->td_sched;
1133	if (smp_started == 0)
1134		return (self);
1135	/*
1136	 * Don't migrate a running thread from sched_switch().
1137	 */
1138	if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td))
1139		return (ts->ts_cpu);
1140	/*
1141	 * Prefer to run interrupt threads on the processors that generate
1142	 * the interrupt.
1143	 */
1144	if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) &&
1145	    curthread->td_intr_nesting_level && ts->ts_cpu != self) {
1146		SCHED_STAT_INC(pickcpu_intrbind);
1147		ts->ts_cpu = self;
1148	}
1149	/*
1150	 * If the thread can run on the last cpu and the affinity has not
1151	 * expired or it is idle run it there.
1152	 */
1153	pri = td->td_priority;
1154	tdq = TDQ_CPU(ts->ts_cpu);
1155	if (THREAD_CAN_SCHED(td, ts->ts_cpu)) {
1156		if (tdq->tdq_lowpri > PRI_MIN_IDLE) {
1157			SCHED_STAT_INC(pickcpu_idle_affinity);
1158			return (ts->ts_cpu);
1159		}
1160		if (SCHED_AFFINITY(ts, CG_SHARE_L2) && tdq->tdq_lowpri > pri) {
1161			SCHED_STAT_INC(pickcpu_affinity);
1162			return (ts->ts_cpu);
1163		}
1164	}
1165	/*
1166	 * Search for the highest level in the tree that still has affinity.
1167	 */
1168	cg = NULL;
1169	for (cg = tdq->tdq_cg; cg != NULL; cg = cg->cg_parent)
1170		if (SCHED_AFFINITY(ts, cg->cg_level))
1171			break;
1172	cpu = -1;
1173	mask = td->td_cpuset->cs_mask;
1174	if (cg)
1175		cpu = sched_lowest(cg, mask, pri);
1176	if (cpu == -1)
1177		cpu = sched_lowest(cpu_top, mask, -1);
1178	/*
1179	 * Compare the lowest loaded cpu to current cpu.
1180	 */
1181	if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri &&
1182	    TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE) {
1183		SCHED_STAT_INC(pickcpu_local);
1184		cpu = self;
1185	} else
1186		SCHED_STAT_INC(pickcpu_lowest);
1187	if (cpu != ts->ts_cpu)
1188		SCHED_STAT_INC(pickcpu_migration);
1189	KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu."));
1190	return (cpu);
1191}
1192#endif
1193
1194/*
1195 * Pick the highest priority task we have and return it.
1196 */
1197static struct thread *
1198tdq_choose(struct tdq *tdq)
1199{
1200	struct thread *td;
1201
1202	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1203	td = runq_choose(&tdq->tdq_realtime);
1204	if (td != NULL)
1205		return (td);
1206	td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx);
1207	if (td != NULL) {
1208		KASSERT(td->td_priority >= PRI_MIN_TIMESHARE,
1209		    ("tdq_choose: Invalid priority on timeshare queue %d",
1210		    td->td_priority));
1211		return (td);
1212	}
1213	td = runq_choose(&tdq->tdq_idle);
1214	if (td != NULL) {
1215		KASSERT(td->td_priority >= PRI_MIN_IDLE,
1216		    ("tdq_choose: Invalid priority on idle queue %d",
1217		    td->td_priority));
1218		return (td);
1219	}
1220
1221	return (NULL);
1222}
1223
1224/*
1225 * Initialize a thread queue.
1226 */
1227static void
1228tdq_setup(struct tdq *tdq)
1229{
1230
1231	if (bootverbose)
1232		printf("ULE: setup cpu %d\n", TDQ_ID(tdq));
1233	runq_init(&tdq->tdq_realtime);
1234	runq_init(&tdq->tdq_timeshare);
1235	runq_init(&tdq->tdq_idle);
1236	snprintf(tdq->tdq_name, sizeof(tdq->tdq_name),
1237	    "sched lock %d", (int)TDQ_ID(tdq));
1238	mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock",
1239	    MTX_SPIN | MTX_RECURSE);
1240#ifdef KTR
1241	snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname),
1242	    "CPU %d load", (int)TDQ_ID(tdq));
1243#endif
1244}
1245
1246#ifdef SMP
1247static void
1248sched_setup_smp(void)
1249{
1250	struct tdq *tdq;
1251	int i;
1252
1253	cpu_top = smp_topo();
1254	CPU_FOREACH(i) {
1255		tdq = TDQ_CPU(i);
1256		tdq_setup(tdq);
1257		tdq->tdq_cg = smp_topo_find(cpu_top, i);
1258		if (tdq->tdq_cg == NULL)
1259			panic("Can't find cpu group for %d\n", i);
1260	}
1261	balance_tdq = TDQ_SELF();
1262	sched_balance();
1263}
1264#endif
1265
1266/*
1267 * Setup the thread queues and initialize the topology based on MD
1268 * information.
1269 */
1270static void
1271sched_setup(void *dummy)
1272{
1273	struct tdq *tdq;
1274
1275	tdq = TDQ_SELF();
1276#ifdef SMP
1277	sched_setup_smp();
1278#else
1279	tdq_setup(tdq);
1280#endif
1281	/*
1282	 * To avoid divide-by-zero, we set realstathz a dummy value
1283	 * in case which sched_clock() called before sched_initticks().
1284	 */
1285	realstathz = hz;
1286	sched_slice = (realstathz/10);	/* ~100ms */
1287	tickincr = 1 << SCHED_TICK_SHIFT;
1288
1289	/* Add thread0's load since it's running. */
1290	TDQ_LOCK(tdq);
1291	thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF());
1292	tdq_load_add(tdq, &thread0);
1293	tdq->tdq_lowpri = thread0.td_priority;
1294	TDQ_UNLOCK(tdq);
1295}
1296
1297/*
1298 * This routine determines the tickincr after stathz and hz are setup.
1299 */
1300/* ARGSUSED */
1301static void
1302sched_initticks(void *dummy)
1303{
1304	int incr;
1305
1306	realstathz = stathz ? stathz : hz;
1307	sched_slice = (realstathz/10);	/* ~100ms */
1308
1309	/*
1310	 * tickincr is shifted out by 10 to avoid rounding errors due to
1311	 * hz not being evenly divisible by stathz on all platforms.
1312	 */
1313	incr = (hz << SCHED_TICK_SHIFT) / realstathz;
1314	/*
1315	 * This does not work for values of stathz that are more than
1316	 * 1 << SCHED_TICK_SHIFT * hz.  In practice this does not happen.
1317	 */
1318	if (incr == 0)
1319		incr = 1;
1320	tickincr = incr;
1321#ifdef SMP
1322	/*
1323	 * Set the default balance interval now that we know
1324	 * what realstathz is.
1325	 */
1326	balance_interval = realstathz;
1327	/*
1328	 * Set steal thresh to roughly log2(mp_ncpu) but no greater than 4.
1329	 * This prevents excess thrashing on large machines and excess idle
1330	 * on smaller machines.
1331	 */
1332	steal_thresh = min(fls(mp_ncpus) - 1, 3);
1333	affinity = SCHED_AFFINITY_DEFAULT;
1334#endif
1335}
1336
1337
1338/*
1339 * This is the core of the interactivity algorithm.  Determines a score based
1340 * on past behavior.  It is the ratio of sleep time to run time scaled to
1341 * a [0, 100] integer.  This is the voluntary sleep time of a process, which
1342 * differs from the cpu usage because it does not account for time spent
1343 * waiting on a run-queue.  Would be prettier if we had floating point.
1344 */
1345static int
1346sched_interact_score(struct thread *td)
1347{
1348	struct td_sched *ts;
1349	int div;
1350
1351	ts = td->td_sched;
1352	/*
1353	 * The score is only needed if this is likely to be an interactive
1354	 * task.  Don't go through the expense of computing it if there's
1355	 * no chance.
1356	 */
1357	if (sched_interact <= SCHED_INTERACT_HALF &&
1358		ts->ts_runtime >= ts->ts_slptime)
1359			return (SCHED_INTERACT_HALF);
1360
1361	if (ts->ts_runtime > ts->ts_slptime) {
1362		div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF);
1363		return (SCHED_INTERACT_HALF +
1364		    (SCHED_INTERACT_HALF - (ts->ts_slptime / div)));
1365	}
1366	if (ts->ts_slptime > ts->ts_runtime) {
1367		div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF);
1368		return (ts->ts_runtime / div);
1369	}
1370	/* runtime == slptime */
1371	if (ts->ts_runtime)
1372		return (SCHED_INTERACT_HALF);
1373
1374	/*
1375	 * This can happen if slptime and runtime are 0.
1376	 */
1377	return (0);
1378
1379}
1380
1381/*
1382 * Scale the scheduling priority according to the "interactivity" of this
1383 * process.
1384 */
1385static void
1386sched_priority(struct thread *td)
1387{
1388	int score;
1389	int pri;
1390
1391	if (td->td_pri_class != PRI_TIMESHARE)
1392		return;
1393	/*
1394	 * If the score is interactive we place the thread in the realtime
1395	 * queue with a priority that is less than kernel and interrupt
1396	 * priorities.  These threads are not subject to nice restrictions.
1397	 *
1398	 * Scores greater than this are placed on the normal timeshare queue
1399	 * where the priority is partially decided by the most recent cpu
1400	 * utilization and the rest is decided by nice value.
1401	 *
1402	 * The nice value of the process has a linear effect on the calculated
1403	 * score.  Negative nice values make it easier for a thread to be
1404	 * considered interactive.
1405	 */
1406	score = imax(0, sched_interact_score(td) + td->td_proc->p_nice);
1407	if (score < sched_interact) {
1408		pri = PRI_MIN_REALTIME;
1409		pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME + 1) /
1410		    sched_interact) * score;
1411		KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME,
1412		    ("sched_priority: invalid interactive priority %d score %d",
1413		    pri, score));
1414	} else {
1415		pri = SCHED_PRI_MIN;
1416		if (td->td_sched->ts_ticks)
1417			pri += SCHED_PRI_TICKS(td->td_sched);
1418		pri += SCHED_PRI_NICE(td->td_proc->p_nice);
1419		KASSERT(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE,
1420		    ("sched_priority: invalid priority %d: nice %d, "
1421		    "ticks %d ftick %d ltick %d tick pri %d",
1422		    pri, td->td_proc->p_nice, td->td_sched->ts_ticks,
1423		    td->td_sched->ts_ftick, td->td_sched->ts_ltick,
1424		    SCHED_PRI_TICKS(td->td_sched)));
1425	}
1426	sched_user_prio(td, pri);
1427
1428	return;
1429}
1430
1431/*
1432 * This routine enforces a maximum limit on the amount of scheduling history
1433 * kept.  It is called after either the slptime or runtime is adjusted.  This
1434 * function is ugly due to integer math.
1435 */
1436static void
1437sched_interact_update(struct thread *td)
1438{
1439	struct td_sched *ts;
1440	u_int sum;
1441
1442	ts = td->td_sched;
1443	sum = ts->ts_runtime + ts->ts_slptime;
1444	if (sum < SCHED_SLP_RUN_MAX)
1445		return;
1446	/*
1447	 * This only happens from two places:
1448	 * 1) We have added an unusual amount of run time from fork_exit.
1449	 * 2) We have added an unusual amount of sleep time from sched_sleep().
1450	 */
1451	if (sum > SCHED_SLP_RUN_MAX * 2) {
1452		if (ts->ts_runtime > ts->ts_slptime) {
1453			ts->ts_runtime = SCHED_SLP_RUN_MAX;
1454			ts->ts_slptime = 1;
1455		} else {
1456			ts->ts_slptime = SCHED_SLP_RUN_MAX;
1457			ts->ts_runtime = 1;
1458		}
1459		return;
1460	}
1461	/*
1462	 * If we have exceeded by more than 1/5th then the algorithm below
1463	 * will not bring us back into range.  Dividing by two here forces
1464	 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX]
1465	 */
1466	if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) {
1467		ts->ts_runtime /= 2;
1468		ts->ts_slptime /= 2;
1469		return;
1470	}
1471	ts->ts_runtime = (ts->ts_runtime / 5) * 4;
1472	ts->ts_slptime = (ts->ts_slptime / 5) * 4;
1473}
1474
1475/*
1476 * Scale back the interactivity history when a child thread is created.  The
1477 * history is inherited from the parent but the thread may behave totally
1478 * differently.  For example, a shell spawning a compiler process.  We want
1479 * to learn that the compiler is behaving badly very quickly.
1480 */
1481static void
1482sched_interact_fork(struct thread *td)
1483{
1484	int ratio;
1485	int sum;
1486
1487	sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime;
1488	if (sum > SCHED_SLP_RUN_FORK) {
1489		ratio = sum / SCHED_SLP_RUN_FORK;
1490		td->td_sched->ts_runtime /= ratio;
1491		td->td_sched->ts_slptime /= ratio;
1492	}
1493}
1494
1495/*
1496 * Called from proc0_init() to setup the scheduler fields.
1497 */
1498void
1499schedinit(void)
1500{
1501
1502	/*
1503	 * Set up the scheduler specific parts of proc0.
1504	 */
1505	proc0.p_sched = NULL; /* XXX */
1506	thread0.td_sched = &td_sched0;
1507	td_sched0.ts_ltick = ticks;
1508	td_sched0.ts_ftick = ticks;
1509	td_sched0.ts_slice = sched_slice;
1510}
1511
1512/*
1513 * This is only somewhat accurate since given many processes of the same
1514 * priority they will switch when their slices run out, which will be
1515 * at most sched_slice stathz ticks.
1516 */
1517int
1518sched_rr_interval(void)
1519{
1520
1521	/* Convert sched_slice to hz */
1522	return (hz/(realstathz/sched_slice));
1523}
1524
1525/*
1526 * Update the percent cpu tracking information when it is requested or
1527 * the total history exceeds the maximum.  We keep a sliding history of
1528 * tick counts that slowly decays.  This is less precise than the 4BSD
1529 * mechanism since it happens with less regular and frequent events.
1530 */
1531static void
1532sched_pctcpu_update(struct td_sched *ts)
1533{
1534
1535	if (ts->ts_ticks == 0)
1536		return;
1537	if (ticks - (hz / 10) < ts->ts_ltick &&
1538	    SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX)
1539		return;
1540	/*
1541	 * Adjust counters and watermark for pctcpu calc.
1542	 */
1543	if (ts->ts_ltick > ticks - SCHED_TICK_TARG)
1544		ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) *
1545			    SCHED_TICK_TARG;
1546	else
1547		ts->ts_ticks = 0;
1548	ts->ts_ltick = ticks;
1549	ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG;
1550}
1551
1552/*
1553 * Adjust the priority of a thread.  Move it to the appropriate run-queue
1554 * if necessary.  This is the back-end for several priority related
1555 * functions.
1556 */
1557static void
1558sched_thread_priority(struct thread *td, u_char prio)
1559{
1560	struct td_sched *ts;
1561	struct tdq *tdq;
1562	int oldpri;
1563
1564	KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio",
1565	    "prio:%d", td->td_priority, "new prio:%d", prio,
1566	    KTR_ATTR_LINKED, sched_tdname(curthread));
1567	if (td != curthread && prio > td->td_priority) {
1568		KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread),
1569		    "lend prio", "prio:%d", td->td_priority, "new prio:%d",
1570		    prio, KTR_ATTR_LINKED, sched_tdname(td));
1571	}
1572	ts = td->td_sched;
1573	THREAD_LOCK_ASSERT(td, MA_OWNED);
1574	if (td->td_priority == prio)
1575		return;
1576	/*
1577	 * If the priority has been elevated due to priority
1578	 * propagation, we may have to move ourselves to a new
1579	 * queue.  This could be optimized to not re-add in some
1580	 * cases.
1581	 */
1582	if (TD_ON_RUNQ(td) && prio < td->td_priority) {
1583		sched_rem(td);
1584		td->td_priority = prio;
1585		sched_add(td, SRQ_BORROWING);
1586		return;
1587	}
1588	/*
1589	 * If the thread is currently running we may have to adjust the lowpri
1590	 * information so other cpus are aware of our current priority.
1591	 */
1592	if (TD_IS_RUNNING(td)) {
1593		tdq = TDQ_CPU(ts->ts_cpu);
1594		oldpri = td->td_priority;
1595		td->td_priority = prio;
1596		if (prio < tdq->tdq_lowpri)
1597			tdq->tdq_lowpri = prio;
1598		else if (tdq->tdq_lowpri == oldpri)
1599			tdq_setlowpri(tdq, td);
1600		return;
1601	}
1602	td->td_priority = prio;
1603}
1604
1605/*
1606 * Update a thread's priority when it is lent another thread's
1607 * priority.
1608 */
1609void
1610sched_lend_prio(struct thread *td, u_char prio)
1611{
1612
1613	td->td_flags |= TDF_BORROWING;
1614	sched_thread_priority(td, prio);
1615}
1616
1617/*
1618 * Restore a thread's priority when priority propagation is
1619 * over.  The prio argument is the minimum priority the thread
1620 * needs to have to satisfy other possible priority lending
1621 * requests.  If the thread's regular priority is less
1622 * important than prio, the thread will keep a priority boost
1623 * of prio.
1624 */
1625void
1626sched_unlend_prio(struct thread *td, u_char prio)
1627{
1628	u_char base_pri;
1629
1630	if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
1631	    td->td_base_pri <= PRI_MAX_TIMESHARE)
1632		base_pri = td->td_user_pri;
1633	else
1634		base_pri = td->td_base_pri;
1635	if (prio >= base_pri) {
1636		td->td_flags &= ~TDF_BORROWING;
1637		sched_thread_priority(td, base_pri);
1638	} else
1639		sched_lend_prio(td, prio);
1640}
1641
1642/*
1643 * Standard entry for setting the priority to an absolute value.
1644 */
1645void
1646sched_prio(struct thread *td, u_char prio)
1647{
1648	u_char oldprio;
1649
1650	/* First, update the base priority. */
1651	td->td_base_pri = prio;
1652
1653	/*
1654	 * If the thread is borrowing another thread's priority, don't
1655	 * ever lower the priority.
1656	 */
1657	if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
1658		return;
1659
1660	/* Change the real priority. */
1661	oldprio = td->td_priority;
1662	sched_thread_priority(td, prio);
1663
1664	/*
1665	 * If the thread is on a turnstile, then let the turnstile update
1666	 * its state.
1667	 */
1668	if (TD_ON_LOCK(td) && oldprio != prio)
1669		turnstile_adjust(td, oldprio);
1670}
1671
1672/*
1673 * Set the base user priority, does not effect current running priority.
1674 */
1675void
1676sched_user_prio(struct thread *td, u_char prio)
1677{
1678
1679	td->td_base_user_pri = prio;
1680	if (td->td_lend_user_pri <= prio)
1681		return;
1682	td->td_user_pri = prio;
1683}
1684
1685void
1686sched_lend_user_prio(struct thread *td, u_char prio)
1687{
1688
1689	THREAD_LOCK_ASSERT(td, MA_OWNED);
1690	td->td_lend_user_pri = prio;
1691	td->td_user_pri = min(prio, td->td_base_user_pri);
1692	if (td->td_priority > td->td_user_pri)
1693		sched_prio(td, td->td_user_pri);
1694	else if (td->td_priority != td->td_user_pri)
1695		td->td_flags |= TDF_NEEDRESCHED;
1696}
1697
1698/*
1699 * Handle migration from sched_switch().  This happens only for
1700 * cpu binding.
1701 */
1702static struct mtx *
1703sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags)
1704{
1705	struct tdq *tdn;
1706
1707	tdn = TDQ_CPU(td->td_sched->ts_cpu);
1708#ifdef SMP
1709	tdq_load_rem(tdq, td);
1710	/*
1711	 * Do the lock dance required to avoid LOR.  We grab an extra
1712	 * spinlock nesting to prevent preemption while we're
1713	 * not holding either run-queue lock.
1714	 */
1715	spinlock_enter();
1716	thread_lock_block(td);	/* This releases the lock on tdq. */
1717
1718	/*
1719	 * Acquire both run-queue locks before placing the thread on the new
1720	 * run-queue to avoid deadlocks created by placing a thread with a
1721	 * blocked lock on the run-queue of a remote processor.  The deadlock
1722	 * occurs when a third processor attempts to lock the two queues in
1723	 * question while the target processor is spinning with its own
1724	 * run-queue lock held while waiting for the blocked lock to clear.
1725	 */
1726	tdq_lock_pair(tdn, tdq);
1727	tdq_add(tdn, td, flags);
1728	tdq_notify(tdn, td);
1729	TDQ_UNLOCK(tdn);
1730	spinlock_exit();
1731#endif
1732	return (TDQ_LOCKPTR(tdn));
1733}
1734
1735/*
1736 * Variadic version of thread_lock_unblock() that does not assume td_lock
1737 * is blocked.
1738 */
1739static inline void
1740thread_unblock_switch(struct thread *td, struct mtx *mtx)
1741{
1742	atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock,
1743	    (uintptr_t)mtx);
1744}
1745
1746/*
1747 * Switch threads.  This function has to handle threads coming in while
1748 * blocked for some reason, running, or idle.  It also must deal with
1749 * migrating a thread from one queue to another as running threads may
1750 * be assigned elsewhere via binding.
1751 */
1752void
1753sched_switch(struct thread *td, struct thread *newtd, int flags)
1754{
1755	struct tdq *tdq;
1756	struct td_sched *ts;
1757	struct mtx *mtx;
1758	int srqflag;
1759	int cpuid;
1760
1761	THREAD_LOCK_ASSERT(td, MA_OWNED);
1762	KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument"));
1763
1764	cpuid = PCPU_GET(cpuid);
1765	tdq = TDQ_CPU(cpuid);
1766	ts = td->td_sched;
1767	mtx = td->td_lock;
1768	ts->ts_rltick = ticks;
1769	td->td_lastcpu = td->td_oncpu;
1770	td->td_oncpu = NOCPU;
1771	td->td_flags &= ~TDF_NEEDRESCHED;
1772	td->td_owepreempt = 0;
1773	tdq->tdq_switchcnt++;
1774	/*
1775	 * The lock pointer in an idle thread should never change.  Reset it
1776	 * to CAN_RUN as well.
1777	 */
1778	if (TD_IS_IDLETHREAD(td)) {
1779		MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1780		TD_SET_CAN_RUN(td);
1781	} else if (TD_IS_RUNNING(td)) {
1782		MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1783		srqflag = (flags & SW_PREEMPT) ?
1784		    SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
1785		    SRQ_OURSELF|SRQ_YIELDING;
1786#ifdef SMP
1787		if (THREAD_CAN_MIGRATE(td) && !THREAD_CAN_SCHED(td, ts->ts_cpu))
1788			ts->ts_cpu = sched_pickcpu(td, 0);
1789#endif
1790		if (ts->ts_cpu == cpuid)
1791			tdq_runq_add(tdq, td, srqflag);
1792		else {
1793			KASSERT(THREAD_CAN_MIGRATE(td) ||
1794			    (ts->ts_flags & TSF_BOUND) != 0,
1795			    ("Thread %p shouldn't migrate", td));
1796			mtx = sched_switch_migrate(tdq, td, srqflag);
1797		}
1798	} else {
1799		/* This thread must be going to sleep. */
1800		TDQ_LOCK(tdq);
1801		mtx = thread_lock_block(td);
1802		tdq_load_rem(tdq, td);
1803	}
1804	/*
1805	 * We enter here with the thread blocked and assigned to the
1806	 * appropriate cpu run-queue or sleep-queue and with the current
1807	 * thread-queue locked.
1808	 */
1809	TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
1810	newtd = choosethread();
1811	/*
1812	 * Call the MD code to switch contexts if necessary.
1813	 */
1814	if (td != newtd) {
1815#ifdef	HWPMC_HOOKS
1816		if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1817			PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
1818#endif
1819		lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
1820		TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
1821
1822#ifdef KDTRACE_HOOKS
1823		/*
1824		 * If DTrace has set the active vtime enum to anything
1825		 * other than INACTIVE (0), then it should have set the
1826		 * function to call.
1827		 */
1828		if (dtrace_vtime_active)
1829			(*dtrace_vtime_switch_func)(newtd);
1830#endif
1831
1832		cpu_switch(td, newtd, mtx);
1833		/*
1834		 * We may return from cpu_switch on a different cpu.  However,
1835		 * we always return with td_lock pointing to the current cpu's
1836		 * run queue lock.
1837		 */
1838		cpuid = PCPU_GET(cpuid);
1839		tdq = TDQ_CPU(cpuid);
1840		lock_profile_obtain_lock_success(
1841		    &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
1842#ifdef	HWPMC_HOOKS
1843		if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1844			PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
1845#endif
1846	} else
1847		thread_unblock_switch(td, mtx);
1848	/*
1849	 * Assert that all went well and return.
1850	 */
1851	TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED);
1852	MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1853	td->td_oncpu = cpuid;
1854}
1855
1856/*
1857 * Adjust thread priorities as a result of a nice request.
1858 */
1859void
1860sched_nice(struct proc *p, int nice)
1861{
1862	struct thread *td;
1863
1864	PROC_LOCK_ASSERT(p, MA_OWNED);
1865
1866	p->p_nice = nice;
1867	FOREACH_THREAD_IN_PROC(p, td) {
1868		thread_lock(td);
1869		sched_priority(td);
1870		sched_prio(td, td->td_base_user_pri);
1871		thread_unlock(td);
1872	}
1873}
1874
1875/*
1876 * Record the sleep time for the interactivity scorer.
1877 */
1878void
1879sched_sleep(struct thread *td, int prio)
1880{
1881
1882	THREAD_LOCK_ASSERT(td, MA_OWNED);
1883
1884	td->td_slptick = ticks;
1885	if (TD_IS_SUSPENDED(td) || prio >= PSOCK)
1886		td->td_flags |= TDF_CANSWAP;
1887	if (static_boost == 1 && prio)
1888		sched_prio(td, prio);
1889	else if (static_boost && td->td_priority > static_boost)
1890		sched_prio(td, static_boost);
1891}
1892
1893/*
1894 * Schedule a thread to resume execution and record how long it voluntarily
1895 * slept.  We also update the pctcpu, interactivity, and priority.
1896 */
1897void
1898sched_wakeup(struct thread *td)
1899{
1900	struct td_sched *ts;
1901	int slptick;
1902
1903	THREAD_LOCK_ASSERT(td, MA_OWNED);
1904	ts = td->td_sched;
1905	td->td_flags &= ~TDF_CANSWAP;
1906	/*
1907	 * If we slept for more than a tick update our interactivity and
1908	 * priority.
1909	 */
1910	slptick = td->td_slptick;
1911	td->td_slptick = 0;
1912	if (slptick && slptick != ticks) {
1913		u_int hzticks;
1914
1915		hzticks = (ticks - slptick) << SCHED_TICK_SHIFT;
1916		ts->ts_slptime += hzticks;
1917		sched_interact_update(td);
1918		sched_pctcpu_update(ts);
1919	}
1920	/* Reset the slice value after we sleep. */
1921	ts->ts_slice = sched_slice;
1922	sched_add(td, SRQ_BORING);
1923}
1924
1925/*
1926 * Penalize the parent for creating a new child and initialize the child's
1927 * priority.
1928 */
1929void
1930sched_fork(struct thread *td, struct thread *child)
1931{
1932	THREAD_LOCK_ASSERT(td, MA_OWNED);
1933	sched_fork_thread(td, child);
1934	/*
1935	 * Penalize the parent and child for forking.
1936	 */
1937	sched_interact_fork(child);
1938	sched_priority(child);
1939	td->td_sched->ts_runtime += tickincr;
1940	sched_interact_update(td);
1941	sched_priority(td);
1942}
1943
1944/*
1945 * Fork a new thread, may be within the same process.
1946 */
1947void
1948sched_fork_thread(struct thread *td, struct thread *child)
1949{
1950	struct td_sched *ts;
1951	struct td_sched *ts2;
1952
1953	THREAD_LOCK_ASSERT(td, MA_OWNED);
1954	/*
1955	 * Initialize child.
1956	 */
1957	ts = td->td_sched;
1958	ts2 = child->td_sched;
1959	child->td_lock = TDQ_LOCKPTR(TDQ_SELF());
1960	child->td_cpuset = cpuset_ref(td->td_cpuset);
1961	ts2->ts_cpu = ts->ts_cpu;
1962	ts2->ts_flags = 0;
1963	/*
1964	 * Grab our parents cpu estimation information.
1965	 */
1966	ts2->ts_ticks = ts->ts_ticks;
1967	ts2->ts_ltick = ts->ts_ltick;
1968	ts2->ts_incrtick = ts->ts_incrtick;
1969	ts2->ts_ftick = ts->ts_ftick;
1970	/*
1971	 * Do not inherit any borrowed priority from the parent.
1972	 */
1973	child->td_priority = child->td_base_pri;
1974	/*
1975	 * And update interactivity score.
1976	 */
1977	ts2->ts_slptime = ts->ts_slptime;
1978	ts2->ts_runtime = ts->ts_runtime;
1979	ts2->ts_slice = 1;	/* Attempt to quickly learn interactivity. */
1980#ifdef KTR
1981	bzero(ts2->ts_name, sizeof(ts2->ts_name));
1982#endif
1983}
1984
1985/*
1986 * Adjust the priority class of a thread.
1987 */
1988void
1989sched_class(struct thread *td, int class)
1990{
1991
1992	THREAD_LOCK_ASSERT(td, MA_OWNED);
1993	if (td->td_pri_class == class)
1994		return;
1995	td->td_pri_class = class;
1996}
1997
1998/*
1999 * Return some of the child's priority and interactivity to the parent.
2000 */
2001void
2002sched_exit(struct proc *p, struct thread *child)
2003{
2004	struct thread *td;
2005
2006	KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit",
2007	    "prio:td", child->td_priority);
2008	PROC_LOCK_ASSERT(p, MA_OWNED);
2009	td = FIRST_THREAD_IN_PROC(p);
2010	sched_exit_thread(td, child);
2011}
2012
2013/*
2014 * Penalize another thread for the time spent on this one.  This helps to
2015 * worsen the priority and interactivity of processes which schedule batch
2016 * jobs such as make.  This has little effect on the make process itself but
2017 * causes new processes spawned by it to receive worse scores immediately.
2018 */
2019void
2020sched_exit_thread(struct thread *td, struct thread *child)
2021{
2022
2023	KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit",
2024	    "prio:td", child->td_priority);
2025	/*
2026	 * Give the child's runtime to the parent without returning the
2027	 * sleep time as a penalty to the parent.  This causes shells that
2028	 * launch expensive things to mark their children as expensive.
2029	 */
2030	thread_lock(td);
2031	td->td_sched->ts_runtime += child->td_sched->ts_runtime;
2032	sched_interact_update(td);
2033	sched_priority(td);
2034	thread_unlock(td);
2035}
2036
2037void
2038sched_preempt(struct thread *td)
2039{
2040	struct tdq *tdq;
2041
2042	thread_lock(td);
2043	tdq = TDQ_SELF();
2044	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2045	tdq->tdq_ipipending = 0;
2046	if (td->td_priority > tdq->tdq_lowpri) {
2047		int flags;
2048
2049		flags = SW_INVOL | SW_PREEMPT;
2050		if (td->td_critnest > 1)
2051			td->td_owepreempt = 1;
2052		else if (TD_IS_IDLETHREAD(td))
2053			mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL);
2054		else
2055			mi_switch(flags | SWT_REMOTEPREEMPT, NULL);
2056	}
2057	thread_unlock(td);
2058}
2059
2060/*
2061 * Fix priorities on return to user-space.  Priorities may be elevated due
2062 * to static priorities in msleep() or similar.
2063 */
2064void
2065sched_userret(struct thread *td)
2066{
2067	/*
2068	 * XXX we cheat slightly on the locking here to avoid locking in
2069	 * the usual case.  Setting td_priority here is essentially an
2070	 * incomplete workaround for not setting it properly elsewhere.
2071	 * Now that some interrupt handlers are threads, not setting it
2072	 * properly elsewhere can clobber it in the window between setting
2073	 * it here and returning to user mode, so don't waste time setting
2074	 * it perfectly here.
2075	 */
2076	KASSERT((td->td_flags & TDF_BORROWING) == 0,
2077	    ("thread with borrowed priority returning to userland"));
2078	if (td->td_priority != td->td_user_pri) {
2079		thread_lock(td);
2080		td->td_priority = td->td_user_pri;
2081		td->td_base_pri = td->td_user_pri;
2082		tdq_setlowpri(TDQ_SELF(), td);
2083		thread_unlock(td);
2084        }
2085}
2086
2087/*
2088 * Handle a stathz tick.  This is really only relevant for timeshare
2089 * threads.
2090 */
2091void
2092sched_clock(struct thread *td)
2093{
2094	struct tdq *tdq;
2095	struct td_sched *ts;
2096
2097	THREAD_LOCK_ASSERT(td, MA_OWNED);
2098	tdq = TDQ_SELF();
2099#ifdef SMP
2100	/*
2101	 * We run the long term load balancer infrequently on the first cpu.
2102	 */
2103	if (balance_tdq == tdq) {
2104		if (balance_ticks && --balance_ticks == 0)
2105			sched_balance();
2106	}
2107#endif
2108	/*
2109	 * Save the old switch count so we have a record of the last ticks
2110	 * activity.   Initialize the new switch count based on our load.
2111	 * If there is some activity seed it to reflect that.
2112	 */
2113	tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt;
2114	tdq->tdq_switchcnt = tdq->tdq_load;
2115	/*
2116	 * Advance the insert index once for each tick to ensure that all
2117	 * threads get a chance to run.
2118	 */
2119	if (tdq->tdq_idx == tdq->tdq_ridx) {
2120		tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS;
2121		if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx]))
2122			tdq->tdq_ridx = tdq->tdq_idx;
2123	}
2124	ts = td->td_sched;
2125	if (td->td_pri_class & PRI_FIFO_BIT)
2126		return;
2127	if (td->td_pri_class == PRI_TIMESHARE) {
2128		/*
2129		 * We used a tick; charge it to the thread so
2130		 * that we can compute our interactivity.
2131		 */
2132		td->td_sched->ts_runtime += tickincr;
2133		sched_interact_update(td);
2134		sched_priority(td);
2135	}
2136	/*
2137	 * We used up one time slice.
2138	 */
2139	if (--ts->ts_slice > 0)
2140		return;
2141	/*
2142	 * We're out of time, force a requeue at userret().
2143	 */
2144	ts->ts_slice = sched_slice;
2145	td->td_flags |= TDF_NEEDRESCHED;
2146}
2147
2148/*
2149 * Called once per hz tick.  Used for cpu utilization information.  This
2150 * is easier than trying to scale based on stathz.
2151 */
2152void
2153sched_tick(int cnt)
2154{
2155	struct td_sched *ts;
2156
2157	ts = curthread->td_sched;
2158	/*
2159	 * Ticks is updated asynchronously on a single cpu.  Check here to
2160	 * avoid incrementing ts_ticks multiple times in a single tick.
2161	 */
2162	if (ts->ts_incrtick == ticks)
2163		return;
2164	/* Adjust ticks for pctcpu */
2165	ts->ts_ticks += cnt << SCHED_TICK_SHIFT;
2166	ts->ts_ltick = ticks;
2167	ts->ts_incrtick = ticks;
2168	/*
2169	 * Update if we've exceeded our desired tick threshold by over one
2170	 * second.
2171	 */
2172	if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick)
2173		sched_pctcpu_update(ts);
2174}
2175
2176/*
2177 * Return whether the current CPU has runnable tasks.  Used for in-kernel
2178 * cooperative idle threads.
2179 */
2180int
2181sched_runnable(void)
2182{
2183	struct tdq *tdq;
2184	int load;
2185
2186	load = 1;
2187
2188	tdq = TDQ_SELF();
2189	if ((curthread->td_flags & TDF_IDLETD) != 0) {
2190		if (tdq->tdq_load > 0)
2191			goto out;
2192	} else
2193		if (tdq->tdq_load - 1 > 0)
2194			goto out;
2195	load = 0;
2196out:
2197	return (load);
2198}
2199
2200/*
2201 * Choose the highest priority thread to run.  The thread is removed from
2202 * the run-queue while running however the load remains.  For SMP we set
2203 * the tdq in the global idle bitmask if it idles here.
2204 */
2205struct thread *
2206sched_choose(void)
2207{
2208	struct thread *td;
2209	struct tdq *tdq;
2210
2211	tdq = TDQ_SELF();
2212	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2213	td = tdq_choose(tdq);
2214	if (td) {
2215		td->td_sched->ts_ltick = ticks;
2216		tdq_runq_rem(tdq, td);
2217		tdq->tdq_lowpri = td->td_priority;
2218		return (td);
2219	}
2220	tdq->tdq_lowpri = PRI_MAX_IDLE;
2221	return (PCPU_GET(idlethread));
2222}
2223
2224/*
2225 * Set owepreempt if necessary.  Preemption never happens directly in ULE,
2226 * we always request it once we exit a critical section.
2227 */
2228static inline void
2229sched_setpreempt(struct thread *td)
2230{
2231	struct thread *ctd;
2232	int cpri;
2233	int pri;
2234
2235	THREAD_LOCK_ASSERT(curthread, MA_OWNED);
2236
2237	ctd = curthread;
2238	pri = td->td_priority;
2239	cpri = ctd->td_priority;
2240	if (pri < cpri)
2241		ctd->td_flags |= TDF_NEEDRESCHED;
2242	if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd))
2243		return;
2244	if (!sched_shouldpreempt(pri, cpri, 0))
2245		return;
2246	ctd->td_owepreempt = 1;
2247}
2248
2249/*
2250 * Add a thread to a thread queue.  Select the appropriate runq and add the
2251 * thread to it.  This is the internal function called when the tdq is
2252 * predetermined.
2253 */
2254void
2255tdq_add(struct tdq *tdq, struct thread *td, int flags)
2256{
2257
2258	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2259	KASSERT((td->td_inhibitors == 0),
2260	    ("sched_add: trying to run inhibited thread"));
2261	KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
2262	    ("sched_add: bad thread state"));
2263	KASSERT(td->td_flags & TDF_INMEM,
2264	    ("sched_add: thread swapped out"));
2265
2266	if (td->td_priority < tdq->tdq_lowpri)
2267		tdq->tdq_lowpri = td->td_priority;
2268	tdq_runq_add(tdq, td, flags);
2269	tdq_load_add(tdq, td);
2270}
2271
2272/*
2273 * Select the target thread queue and add a thread to it.  Request
2274 * preemption or IPI a remote processor if required.
2275 */
2276void
2277sched_add(struct thread *td, int flags)
2278{
2279	struct tdq *tdq;
2280#ifdef SMP
2281	int cpu;
2282#endif
2283
2284	KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
2285	    "prio:%d", td->td_priority, KTR_ATTR_LINKED,
2286	    sched_tdname(curthread));
2287	KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
2288	    KTR_ATTR_LINKED, sched_tdname(td));
2289	THREAD_LOCK_ASSERT(td, MA_OWNED);
2290	/*
2291	 * Recalculate the priority before we select the target cpu or
2292	 * run-queue.
2293	 */
2294	if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
2295		sched_priority(td);
2296#ifdef SMP
2297	/*
2298	 * Pick the destination cpu and if it isn't ours transfer to the
2299	 * target cpu.
2300	 */
2301	cpu = sched_pickcpu(td, flags);
2302	tdq = sched_setcpu(td, cpu, flags);
2303	tdq_add(tdq, td, flags);
2304	if (cpu != PCPU_GET(cpuid)) {
2305		tdq_notify(tdq, td);
2306		return;
2307	}
2308#else
2309	tdq = TDQ_SELF();
2310	TDQ_LOCK(tdq);
2311	/*
2312	 * Now that the thread is moving to the run-queue, set the lock
2313	 * to the scheduler's lock.
2314	 */
2315	thread_lock_set(td, TDQ_LOCKPTR(tdq));
2316	tdq_add(tdq, td, flags);
2317#endif
2318	if (!(flags & SRQ_YIELDING))
2319		sched_setpreempt(td);
2320}
2321
2322/*
2323 * Remove a thread from a run-queue without running it.  This is used
2324 * when we're stealing a thread from a remote queue.  Otherwise all threads
2325 * exit by calling sched_exit_thread() and sched_throw() themselves.
2326 */
2327void
2328sched_rem(struct thread *td)
2329{
2330	struct tdq *tdq;
2331
2332	KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem",
2333	    "prio:%d", td->td_priority);
2334	tdq = TDQ_CPU(td->td_sched->ts_cpu);
2335	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2336	MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2337	KASSERT(TD_ON_RUNQ(td),
2338	    ("sched_rem: thread not on run queue"));
2339	tdq_runq_rem(tdq, td);
2340	tdq_load_rem(tdq, td);
2341	TD_SET_CAN_RUN(td);
2342	if (td->td_priority == tdq->tdq_lowpri)
2343		tdq_setlowpri(tdq, NULL);
2344}
2345
2346/*
2347 * Fetch cpu utilization information.  Updates on demand.
2348 */
2349fixpt_t
2350sched_pctcpu(struct thread *td)
2351{
2352	fixpt_t pctcpu;
2353	struct td_sched *ts;
2354
2355	pctcpu = 0;
2356	ts = td->td_sched;
2357	if (ts == NULL)
2358		return (0);
2359
2360	THREAD_LOCK_ASSERT(td, MA_OWNED);
2361	if (ts->ts_ticks) {
2362		int rtick;
2363
2364		sched_pctcpu_update(ts);
2365		/* How many rtick per second ? */
2366		rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz);
2367		pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT;
2368	}
2369
2370	return (pctcpu);
2371}
2372
2373/*
2374 * Enforce affinity settings for a thread.  Called after adjustments to
2375 * cpumask.
2376 */
2377void
2378sched_affinity(struct thread *td)
2379{
2380#ifdef SMP
2381	struct td_sched *ts;
2382
2383	THREAD_LOCK_ASSERT(td, MA_OWNED);
2384	ts = td->td_sched;
2385	if (THREAD_CAN_SCHED(td, ts->ts_cpu))
2386		return;
2387	if (TD_ON_RUNQ(td)) {
2388		sched_rem(td);
2389		sched_add(td, SRQ_BORING);
2390		return;
2391	}
2392	if (!TD_IS_RUNNING(td))
2393		return;
2394	/*
2395	 * Force a switch before returning to userspace.  If the
2396	 * target thread is not running locally send an ipi to force
2397	 * the issue.
2398	 */
2399	td->td_flags |= TDF_NEEDRESCHED;
2400	if (td != curthread)
2401		ipi_cpu(ts->ts_cpu, IPI_PREEMPT);
2402#endif
2403}
2404
2405/*
2406 * Bind a thread to a target cpu.
2407 */
2408void
2409sched_bind(struct thread *td, int cpu)
2410{
2411	struct td_sched *ts;
2412
2413	THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED);
2414	KASSERT(td == curthread, ("sched_bind: can only bind curthread"));
2415	ts = td->td_sched;
2416	if (ts->ts_flags & TSF_BOUND)
2417		sched_unbind(td);
2418	KASSERT(THREAD_CAN_MIGRATE(td), ("%p must be migratable", td));
2419	ts->ts_flags |= TSF_BOUND;
2420	sched_pin();
2421	if (PCPU_GET(cpuid) == cpu)
2422		return;
2423	ts->ts_cpu = cpu;
2424	/* When we return from mi_switch we'll be on the correct cpu. */
2425	mi_switch(SW_VOL, NULL);
2426}
2427
2428/*
2429 * Release a bound thread.
2430 */
2431void
2432sched_unbind(struct thread *td)
2433{
2434	struct td_sched *ts;
2435
2436	THREAD_LOCK_ASSERT(td, MA_OWNED);
2437	KASSERT(td == curthread, ("sched_unbind: can only bind curthread"));
2438	ts = td->td_sched;
2439	if ((ts->ts_flags & TSF_BOUND) == 0)
2440		return;
2441	ts->ts_flags &= ~TSF_BOUND;
2442	sched_unpin();
2443}
2444
2445int
2446sched_is_bound(struct thread *td)
2447{
2448	THREAD_LOCK_ASSERT(td, MA_OWNED);
2449	return (td->td_sched->ts_flags & TSF_BOUND);
2450}
2451
2452/*
2453 * Basic yield call.
2454 */
2455void
2456sched_relinquish(struct thread *td)
2457{
2458	thread_lock(td);
2459	mi_switch(SW_VOL | SWT_RELINQUISH, NULL);
2460	thread_unlock(td);
2461}
2462
2463/*
2464 * Return the total system load.
2465 */
2466int
2467sched_load(void)
2468{
2469#ifdef SMP
2470	int total;
2471	int i;
2472
2473	total = 0;
2474	CPU_FOREACH(i)
2475		total += TDQ_CPU(i)->tdq_sysload;
2476	return (total);
2477#else
2478	return (TDQ_SELF()->tdq_sysload);
2479#endif
2480}
2481
2482int
2483sched_sizeof_proc(void)
2484{
2485	return (sizeof(struct proc));
2486}
2487
2488int
2489sched_sizeof_thread(void)
2490{
2491	return (sizeof(struct thread) + sizeof(struct td_sched));
2492}
2493
2494#ifdef SMP
2495#define	TDQ_IDLESPIN(tdq)						\
2496    ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0)
2497#else
2498#define	TDQ_IDLESPIN(tdq)	1
2499#endif
2500
2501/*
2502 * The actual idle process.
2503 */
2504void
2505sched_idletd(void *dummy)
2506{
2507	struct thread *td;
2508	struct tdq *tdq;
2509	int switchcnt;
2510	int i;
2511
2512	mtx_assert(&Giant, MA_NOTOWNED);
2513	td = curthread;
2514	tdq = TDQ_SELF();
2515	for (;;) {
2516#ifdef SMP
2517		if (tdq_idled(tdq) == 0)
2518			continue;
2519#endif
2520		switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2521		/*
2522		 * If we're switching very frequently, spin while checking
2523		 * for load rather than entering a low power state that
2524		 * may require an IPI.  However, don't do any busy
2525		 * loops while on SMT machines as this simply steals
2526		 * cycles from cores doing useful work.
2527		 */
2528		if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) {
2529			for (i = 0; i < sched_idlespins; i++) {
2530				if (tdq->tdq_load)
2531					break;
2532				cpu_spinwait();
2533			}
2534		}
2535		switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2536		if (tdq->tdq_load == 0) {
2537			tdq->tdq_cpu_idle = 1;
2538			if (tdq->tdq_load == 0) {
2539				cpu_idle(switchcnt > sched_idlespinthresh * 4);
2540				tdq->tdq_switchcnt++;
2541			}
2542			tdq->tdq_cpu_idle = 0;
2543		}
2544		if (tdq->tdq_load) {
2545			thread_lock(td);
2546			mi_switch(SW_VOL | SWT_IDLE, NULL);
2547			thread_unlock(td);
2548		}
2549	}
2550}
2551
2552/*
2553 * A CPU is entering for the first time or a thread is exiting.
2554 */
2555void
2556sched_throw(struct thread *td)
2557{
2558	struct thread *newtd;
2559	struct tdq *tdq;
2560
2561	tdq = TDQ_SELF();
2562	if (td == NULL) {
2563		/* Correct spinlock nesting and acquire the correct lock. */
2564		TDQ_LOCK(tdq);
2565		spinlock_exit();
2566	} else {
2567		MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2568		tdq_load_rem(tdq, td);
2569		lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
2570	}
2571	KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
2572	newtd = choosethread();
2573	TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
2574	PCPU_SET(switchtime, cpu_ticks());
2575	PCPU_SET(switchticks, ticks);
2576	cpu_throw(td, newtd);		/* doesn't return */
2577}
2578
2579/*
2580 * This is called from fork_exit().  Just acquire the correct locks and
2581 * let fork do the rest of the work.
2582 */
2583void
2584sched_fork_exit(struct thread *td)
2585{
2586	struct td_sched *ts;
2587	struct tdq *tdq;
2588	int cpuid;
2589
2590	/*
2591	 * Finish setting up thread glue so that it begins execution in a
2592	 * non-nested critical section with the scheduler lock held.
2593	 */
2594	cpuid = PCPU_GET(cpuid);
2595	tdq = TDQ_CPU(cpuid);
2596	ts = td->td_sched;
2597	if (TD_IS_IDLETHREAD(td))
2598		td->td_lock = TDQ_LOCKPTR(tdq);
2599	MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2600	td->td_oncpu = cpuid;
2601	TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
2602	lock_profile_obtain_lock_success(
2603	    &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
2604}
2605
2606/*
2607 * Create on first use to catch odd startup conditons.
2608 */
2609char *
2610sched_tdname(struct thread *td)
2611{
2612#ifdef KTR
2613	struct td_sched *ts;
2614
2615	ts = td->td_sched;
2616	if (ts->ts_name[0] == '\0')
2617		snprintf(ts->ts_name, sizeof(ts->ts_name),
2618		    "%s tid %d", td->td_name, td->td_tid);
2619	return (ts->ts_name);
2620#else
2621	return (td->td_name);
2622#endif
2623}
2624
2625#ifdef SMP
2626
2627/*
2628 * Build the CPU topology dump string. Is recursively called to collect
2629 * the topology tree.
2630 */
2631static int
2632sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg,
2633    int indent)
2634{
2635	int i, first;
2636
2637	sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent,
2638	    "", 1 + indent / 2, cg->cg_level);
2639	sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"0x%x\">", indent, "",
2640	    cg->cg_count, cg->cg_mask);
2641	first = TRUE;
2642	for (i = 0; i < MAXCPU; i++) {
2643		if ((cg->cg_mask & (1 << i)) != 0) {
2644			if (!first)
2645				sbuf_printf(sb, ", ");
2646			else
2647				first = FALSE;
2648			sbuf_printf(sb, "%d", i);
2649		}
2650	}
2651	sbuf_printf(sb, "</cpu>\n");
2652
2653	if (cg->cg_flags != 0) {
2654		sbuf_printf(sb, "%*s <flags>", indent, "");
2655		if ((cg->cg_flags & CG_FLAG_HTT) != 0)
2656			sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>");
2657		if ((cg->cg_flags & CG_FLAG_THREAD) != 0)
2658			sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>");
2659		if ((cg->cg_flags & CG_FLAG_SMT) != 0)
2660			sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>");
2661		sbuf_printf(sb, "</flags>\n");
2662	}
2663
2664	if (cg->cg_children > 0) {
2665		sbuf_printf(sb, "%*s <children>\n", indent, "");
2666		for (i = 0; i < cg->cg_children; i++)
2667			sysctl_kern_sched_topology_spec_internal(sb,
2668			    &cg->cg_child[i], indent+2);
2669		sbuf_printf(sb, "%*s </children>\n", indent, "");
2670	}
2671	sbuf_printf(sb, "%*s</group>\n", indent, "");
2672	return (0);
2673}
2674
2675/*
2676 * Sysctl handler for retrieving topology dump. It's a wrapper for
2677 * the recursive sysctl_kern_smp_topology_spec_internal().
2678 */
2679static int
2680sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS)
2681{
2682	struct sbuf *topo;
2683	int err;
2684
2685	KASSERT(cpu_top != NULL, ("cpu_top isn't initialized"));
2686
2687	topo = sbuf_new(NULL, NULL, 500, SBUF_AUTOEXTEND);
2688	if (topo == NULL)
2689		return (ENOMEM);
2690
2691	sbuf_printf(topo, "<groups>\n");
2692	err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1);
2693	sbuf_printf(topo, "</groups>\n");
2694
2695	if (err == 0) {
2696		sbuf_finish(topo);
2697		err = SYSCTL_OUT(req, sbuf_data(topo), sbuf_len(topo));
2698	}
2699	sbuf_delete(topo);
2700	return (err);
2701}
2702
2703#endif
2704
2705SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler");
2706SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0,
2707    "Scheduler name");
2708SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
2709    "Slice size for timeshare threads");
2710SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0,
2711     "Interactivity score threshold");
2712SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh,
2713     0,"Min priority for preemption, lower priorities have greater precedence");
2714SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost,
2715     0,"Controls whether static kernel priorities are assigned to sleeping threads.");
2716SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins,
2717     0,"Number of times idle will spin waiting for new work.");
2718SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW, &sched_idlespinthresh,
2719     0,"Threshold before we will permit idle spinning.");
2720#ifdef SMP
2721SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0,
2722    "Number of hz ticks to keep thread affinity for");
2723SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0,
2724    "Enables the long-term load balancer");
2725SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW,
2726    &balance_interval, 0,
2727    "Average frequency in stathz ticks to run the long-term balancer");
2728SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0,
2729    "Steals work from another hyper-threaded core on idle");
2730SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0,
2731    "Attempts to steal work from other cores before idling");
2732SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0,
2733    "Minimum load on remote cpu before we'll steal");
2734
2735/* Retrieve SMP topology */
2736SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING |
2737    CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A",
2738    "XML dump of detected CPU topology");
2739
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