FreeBSD kernel kern code
sched_ule.c
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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 285353 2015-07-10 08:54:12Z kib $");
40 
41 #include "opt_hwpmc_hooks.h"
42 #include "opt_sched.h"
43 
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kdb.h>
47 #include <sys/kernel.h>
48 #include <sys/ktr.h>
49 #include <sys/limits.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/sdt.h>
57 #include <sys/smp.h>
58 #include <sys/sx.h>
59 #include <sys/sysctl.h>
60 #include <sys/sysproto.h>
61 #include <sys/turnstile.h>
62 #include <sys/umtx.h>
63 #include <sys/vmmeter.h>
64 #include <sys/cpuset.h>
65 #include <sys/sbuf.h>
66 
67 #ifdef HWPMC_HOOKS
68 #include <sys/pmckern.h>
69 #endif
70 
71 #ifdef KDTRACE_HOOKS
72 #include <sys/dtrace_bsd.h>
73 int dtrace_vtime_active;
74 dtrace_vtime_switch_func_t dtrace_vtime_switch_func;
75 #endif
76 
77 #include <machine/cpu.h>
78 #include <machine/smp.h>
79 
80 #define KTR_ULE 0
81 
82 #define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX)))
83 #define TDQ_NAME_LEN (sizeof("sched lock ") + sizeof(__XSTRING(MAXCPU)))
84 #define TDQ_LOADNAME_LEN (sizeof("CPU ") + sizeof(__XSTRING(MAXCPU)) - 1 + sizeof(" load"))
85 
86 /*
87  * Thread scheduler specific section. All fields are protected
88  * by the thread lock.
89  */
90 struct td_sched {
91  struct runq *ts_runq; /* Run-queue we're queued on. */
92  short ts_flags; /* TSF_* flags. */
93  int ts_cpu; /* CPU that we have affinity for. */
94  int ts_rltick; /* Real last tick, for affinity. */
95  int ts_slice; /* Ticks of slice remaining. */
96  u_int ts_slptime; /* Number of ticks we vol. slept */
97  u_int ts_runtime; /* Number of ticks we were running */
98  int ts_ltick; /* Last tick that we were running on */
99  int ts_ftick; /* First tick that we were running on */
100  int ts_ticks; /* Tick count */
101 #ifdef KTR
102  char ts_name[TS_NAME_LEN];
103 #endif
104 };
105 /* flags kept in ts_flags */
106 #define TSF_BOUND 0x0001 /* Thread can not migrate. */
107 #define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */
108 
109 static struct td_sched td_sched0;
110 
111 #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0)
112 #define THREAD_CAN_SCHED(td, cpu) \
113  CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask)
114 
115 /*
116  * Priority ranges used for interactive and non-interactive timeshare
117  * threads. The timeshare priorities are split up into four ranges.
118  * The first range handles interactive threads. The last three ranges
119  * (NHALF, x, and NHALF) handle non-interactive threads with the outer
120  * ranges supporting nice values.
121  */
122 #define PRI_TIMESHARE_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1)
123 #define PRI_INTERACT_RANGE ((PRI_TIMESHARE_RANGE - SCHED_PRI_NRESV) / 2)
124 #define PRI_BATCH_RANGE (PRI_TIMESHARE_RANGE - PRI_INTERACT_RANGE)
125 
126 #define PRI_MIN_INTERACT PRI_MIN_TIMESHARE
127 #define PRI_MAX_INTERACT (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE - 1)
128 #define PRI_MIN_BATCH (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE)
129 #define PRI_MAX_BATCH PRI_MAX_TIMESHARE
130 
131 /*
132  * Cpu percentage computation macros and defines.
133  *
134  * SCHED_TICK_SECS: Number of seconds to average the cpu usage across.
135  * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across.
136  * SCHED_TICK_MAX: Maximum number of ticks before scaling back.
137  * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results.
138  * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count.
139  * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks.
140  */
141 #define SCHED_TICK_SECS 10
142 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS)
143 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz)
144 #define SCHED_TICK_SHIFT 10
145 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT)
146 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz))
147 
148 /*
149  * These macros determine priorities for non-interactive threads. They are
150  * assigned a priority based on their recent cpu utilization as expressed
151  * by the ratio of ticks to the tick total. NHALF priorities at the start
152  * and end of the MIN to MAX timeshare range are only reachable with negative
153  * or positive nice respectively.
154  *
155  * PRI_RANGE: Priority range for utilization dependent priorities.
156  * PRI_NRESV: Number of nice values.
157  * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total.
158  * PRI_NICE: Determines the part of the priority inherited from nice.
159  */
160 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN)
161 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2)
162 #define SCHED_PRI_MIN (PRI_MIN_BATCH + SCHED_PRI_NHALF)
163 #define SCHED_PRI_MAX (PRI_MAX_BATCH - SCHED_PRI_NHALF)
164 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN + 1)
165 #define SCHED_PRI_TICKS(ts) \
166  (SCHED_TICK_HZ((ts)) / \
167  (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE))
168 #define SCHED_PRI_NICE(nice) (nice)
169 
170 /*
171  * These determine the interactivity of a process. Interactivity differs from
172  * cpu utilization in that it expresses the voluntary time slept vs time ran
173  * while cpu utilization includes all time not running. This more accurately
174  * models the intent of the thread.
175  *
176  * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate
177  * before throttling back.
178  * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time.
179  * INTERACT_MAX: Maximum interactivity value. Smaller is better.
180  * INTERACT_THRESH: Threshold for placement on the current runq.
181  */
182 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT)
183 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT)
184 #define SCHED_INTERACT_MAX (100)
185 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2)
186 #define SCHED_INTERACT_THRESH (30)
187 
188 /*
189  * These parameters determine the slice behavior for batch work.
190  */
191 #define SCHED_SLICE_DEFAULT_DIVISOR 10 /* ~94 ms, 12 stathz ticks. */
192 #define SCHED_SLICE_MIN_DIVISOR 6 /* DEFAULT/MIN = ~16 ms. */
193 
194 /* Flags kept in td_flags. */
195 #define TDF_SLICEEND TDF_SCHED2 /* Thread time slice is over. */
196 
197 /*
198  * tickincr: Converts a stathz tick into a hz domain scaled by
199  * the shift factor. Without the shift the error rate
200  * due to rounding would be unacceptably high.
201  * realstathz: stathz is sometimes 0 and run off of hz.
202  * sched_slice: Runtime of each thread before rescheduling.
203  * preempt_thresh: Priority threshold for preemption and remote IPIs.
204  */
206 static int tickincr = 8 << SCHED_TICK_SHIFT;
207 static int realstathz = 127; /* reset during boot. */
208 static int sched_slice = 10; /* reset during boot. */
209 static int sched_slice_min = 1; /* reset during boot. */
210 #ifdef PREEMPTION
211 #ifdef FULL_PREEMPTION
212 static int preempt_thresh = PRI_MAX_IDLE;
213 #else
214 static int preempt_thresh = PRI_MIN_KERN;
215 #endif
216 #else
217 static int preempt_thresh = 0;
218 #endif
220 static int sched_idlespins = 10000;
221 static int sched_idlespinthresh = -1;
222 
223 /*
224  * tdq - per processor runqs and statistics. All fields are protected by the
225  * tdq_lock. The load and lowpri may be accessed without to avoid excess
226  * locking in sched_pickcpu();
227  */
228 struct tdq {
229  /*
230  * Ordered to improve efficiency of cpu_search() and switch().
231  * tdq_lock is padded to avoid false sharing with tdq_load and
232  * tdq_cpu_idle.
233  */
234  struct mtx_padalign tdq_lock; /* run queue lock. */
235  struct cpu_group *tdq_cg; /* Pointer to cpu topology. */
236  volatile int tdq_load; /* Aggregate load. */
237  volatile int tdq_cpu_idle; /* cpu_idle() is active. */
238  int tdq_sysload; /* For loadavg, !ITHD load. */
239  int tdq_transferable; /* Transferable thread count. */
240  short tdq_switchcnt; /* Switches this tick. */
241  short tdq_oldswitchcnt; /* Switches last tick. */
242  u_char tdq_lowpri; /* Lowest priority thread. */
243  u_char tdq_ipipending; /* IPI pending. */
244  u_char tdq_idx; /* Current insert index. */
245  u_char tdq_ridx; /* Current removal index. */
246  struct runq tdq_realtime; /* real-time run queue. */
247  struct runq tdq_timeshare; /* timeshare run queue. */
248  struct runq tdq_idle; /* Queue of IDLE threads. */
250 #ifdef KTR
251  char tdq_loadname[TDQ_LOADNAME_LEN];
252 #endif
253 } __aligned(64);
254 
255 /* Idle thread states and config. */
256 #define TDQ_RUNNING 1
257 #define TDQ_IDLE 2
258 
259 #ifdef SMP
260 struct cpu_group *cpu_top; /* CPU topology */
261 
262 #define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000))
263 #define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity))
264 
265 /*
266  * Run-time tunables.
267  */
268 static int rebalance = 1;
269 static int balance_interval = 128; /* Default set in sched_initticks(). */
270 static int affinity;
271 static int steal_idle = 1;
272 static int steal_thresh = 2;
273 
274 /*
275  * One thread queue per processor.
276  */
277 static struct tdq tdq_cpu[MAXCPU];
278 static struct tdq *balance_tdq;
279 static int balance_ticks;
280 static DPCPU_DEFINE(uint32_t, randomval);
281 
282 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)])
283 #define TDQ_CPU(x) (&tdq_cpu[(x)])
284 #define TDQ_ID(x) ((int)((x) - tdq_cpu))
285 #else /* !SMP */
286 static struct tdq tdq_cpu;
287 
288 #define TDQ_ID(x) (0)
289 #define TDQ_SELF() (&tdq_cpu)
290 #define TDQ_CPU(x) (&tdq_cpu)
291 #endif
292 
293 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type))
294 #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t)))
295 #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f))
296 #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t)))
297 #define TDQ_LOCKPTR(t) ((struct mtx *)(&(t)->tdq_lock))
298 
299 static void sched_priority(struct thread *);
300 static void sched_thread_priority(struct thread *, u_char);
301 static int sched_interact_score(struct thread *);
302 static void sched_interact_update(struct thread *);
303 static void sched_interact_fork(struct thread *);
304 static void sched_pctcpu_update(struct td_sched *, int);
305 
306 /* Operations on per processor queues */
307 static struct thread *tdq_choose(struct tdq *);
308 static void tdq_setup(struct tdq *);
309 static void tdq_load_add(struct tdq *, struct thread *);
310 static void tdq_load_rem(struct tdq *, struct thread *);
311 static __inline void tdq_runq_add(struct tdq *, struct thread *, int);
312 static __inline void tdq_runq_rem(struct tdq *, struct thread *);
313 static inline int sched_shouldpreempt(int, int, int);
314 void tdq_print(int cpu);
315 static void runq_print(struct runq *rq);
316 static void tdq_add(struct tdq *, struct thread *, int);
317 #ifdef SMP
318 static int tdq_move(struct tdq *, struct tdq *);
319 static int tdq_idled(struct tdq *);
320 static void tdq_notify(struct tdq *, struct thread *);
321 static struct thread *tdq_steal(struct tdq *, int);
322 static struct thread *runq_steal(struct runq *, int);
323 static int sched_pickcpu(struct thread *, int);
324 static void sched_balance(void);
325 static int sched_balance_pair(struct tdq *, struct tdq *);
326 static inline struct tdq *sched_setcpu(struct thread *, int, int);
327 static inline void thread_unblock_switch(struct thread *, struct mtx *);
328 static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int);
329 static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS);
330 static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb,
331  struct cpu_group *cg, int indent);
332 #endif
333 
334 static void sched_setup(void *dummy);
335 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
336 
337 static void sched_initticks(void *dummy);
338 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks,
339  NULL);
340 
341 SDT_PROVIDER_DEFINE(sched);
342 
343 SDT_PROBE_DEFINE3(sched, , , change__pri, "struct thread *",
344  "struct proc *", "uint8_t");
345 SDT_PROBE_DEFINE3(sched, , , dequeue, "struct thread *",
346  "struct proc *", "void *");
347 SDT_PROBE_DEFINE4(sched, , , enqueue, "struct thread *",
348  "struct proc *", "void *", "int");
349 SDT_PROBE_DEFINE4(sched, , , lend__pri, "struct thread *",
350  "struct proc *", "uint8_t", "struct thread *");
351 SDT_PROBE_DEFINE2(sched, , , load__change, "int", "int");
352 SDT_PROBE_DEFINE2(sched, , , off__cpu, "struct thread *",
353  "struct proc *");
354 SDT_PROBE_DEFINE(sched, , , on__cpu);
355 SDT_PROBE_DEFINE(sched, , , remain__cpu);
356 SDT_PROBE_DEFINE2(sched, , , surrender, "struct thread *",
357  "struct proc *");
358 
359 /*
360  * Print the threads waiting on a run-queue.
361  */
362 static void
363 runq_print(struct runq *rq)
364 {
365  struct rqhead *rqh;
366  struct thread *td;
367  int pri;
368  int j;
369  int i;
370 
371  for (i = 0; i < RQB_LEN; i++) {
372  printf("\t\trunq bits %d 0x%zx\n",
373  i, rq->rq_status.rqb_bits[i]);
374  for (j = 0; j < RQB_BPW; j++)
375  if (rq->rq_status.rqb_bits[i] & (1ul << j)) {
376  pri = j + (i << RQB_L2BPW);
377  rqh = &rq->rq_queues[pri];
378  TAILQ_FOREACH(td, rqh, td_runq) {
379  printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n",
380  td, td->td_name, td->td_priority,
381  td->td_rqindex, pri);
382  }
383  }
384  }
385 }
386 
387 /*
388  * Print the status of a per-cpu thread queue. Should be a ddb show cmd.
389  */
390 void
391 tdq_print(int cpu)
392 {
393  struct tdq *tdq;
394 
395  tdq = TDQ_CPU(cpu);
396 
397  printf("tdq %d:\n", TDQ_ID(tdq));
398  printf("\tlock %p\n", TDQ_LOCKPTR(tdq));
399  printf("\tLock name: %s\n", tdq->tdq_name);
400  printf("\tload: %d\n", tdq->tdq_load);
401  printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt);
402  printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt);
403  printf("\ttimeshare idx: %d\n", tdq->tdq_idx);
404  printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx);
405  printf("\tload transferable: %d\n", tdq->tdq_transferable);
406  printf("\tlowest priority: %d\n", tdq->tdq_lowpri);
407  printf("\trealtime runq:\n");
408  runq_print(&tdq->tdq_realtime);
409  printf("\ttimeshare runq:\n");
410  runq_print(&tdq->tdq_timeshare);
411  printf("\tidle runq:\n");
412  runq_print(&tdq->tdq_idle);
413 }
414 
415 static inline int
416 sched_shouldpreempt(int pri, int cpri, int remote)
417 {
418  /*
419  * If the new priority is not better than the current priority there is
420  * nothing to do.
421  */
422  if (pri >= cpri)
423  return (0);
424  /*
425  * Always preempt idle.
426  */
427  if (cpri >= PRI_MIN_IDLE)
428  return (1);
429  /*
430  * If preemption is disabled don't preempt others.
431  */
432  if (preempt_thresh == 0)
433  return (0);
434  /*
435  * Preempt if we exceed the threshold.
436  */
437  if (pri <= preempt_thresh)
438  return (1);
439  /*
440  * If we're interactive or better and there is non-interactive
441  * or worse running preempt only remote processors.
442  */
443  if (remote && pri <= PRI_MAX_INTERACT && cpri > PRI_MAX_INTERACT)
444  return (1);
445  return (0);
446 }
447 
448 /*
449  * Add a thread to the actual run-queue. Keeps transferable counts up to
450  * date with what is actually on the run-queue. Selects the correct
451  * queue position for timeshare threads.
452  */
453 static __inline void
454 tdq_runq_add(struct tdq *tdq, struct thread *td, int flags)
455 {
456  struct td_sched *ts;
457  u_char pri;
458 
459  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
460  THREAD_LOCK_ASSERT(td, MA_OWNED);
461 
462  pri = td->td_priority;
463  ts = td->td_sched;
464  TD_SET_RUNQ(td);
465  if (THREAD_CAN_MIGRATE(td)) {
466  tdq->tdq_transferable++;
467  ts->ts_flags |= TSF_XFERABLE;
468  }
469  if (pri < PRI_MIN_BATCH) {
470  ts->ts_runq = &tdq->tdq_realtime;
471  } else if (pri <= PRI_MAX_BATCH) {
472  ts->ts_runq = &tdq->tdq_timeshare;
473  KASSERT(pri <= PRI_MAX_BATCH && pri >= PRI_MIN_BATCH,
474  ("Invalid priority %d on timeshare runq", pri));
475  /*
476  * This queue contains only priorities between MIN and MAX
477  * realtime. Use the whole queue to represent these values.
478  */
479  if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) {
480  pri = RQ_NQS * (pri - PRI_MIN_BATCH) / PRI_BATCH_RANGE;
481  pri = (pri + tdq->tdq_idx) % RQ_NQS;
482  /*
483  * This effectively shortens the queue by one so we
484  * can have a one slot difference between idx and
485  * ridx while we wait for threads to drain.
486  */
487  if (tdq->tdq_ridx != tdq->tdq_idx &&
488  pri == tdq->tdq_ridx)
489  pri = (unsigned char)(pri - 1) % RQ_NQS;
490  } else
491  pri = tdq->tdq_ridx;
492  runq_add_pri(ts->ts_runq, td, pri, flags);
493  return;
494  } else
495  ts->ts_runq = &tdq->tdq_idle;
496  runq_add(ts->ts_runq, td, flags);
497 }
498 
499 /*
500  * Remove a thread from a run-queue. This typically happens when a thread
501  * is selected to run. Running threads are not on the queue and the
502  * transferable count does not reflect them.
503  */
504 static __inline void
505 tdq_runq_rem(struct tdq *tdq, struct thread *td)
506 {
507  struct td_sched *ts;
508 
509  ts = td->td_sched;
510  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
511  KASSERT(ts->ts_runq != NULL,
512  ("tdq_runq_remove: thread %p null ts_runq", td));
513  if (ts->ts_flags & TSF_XFERABLE) {
514  tdq->tdq_transferable--;
515  ts->ts_flags &= ~TSF_XFERABLE;
516  }
517  if (ts->ts_runq == &tdq->tdq_timeshare) {
518  if (tdq->tdq_idx != tdq->tdq_ridx)
519  runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx);
520  else
521  runq_remove_idx(ts->ts_runq, td, NULL);
522  } else
523  runq_remove(ts->ts_runq, td);
524 }
525 
526 /*
527  * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load
528  * for this thread to the referenced thread queue.
529  */
530 static void
531 tdq_load_add(struct tdq *tdq, struct thread *td)
532 {
533 
534  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
535  THREAD_LOCK_ASSERT(td, MA_OWNED);
536 
537  tdq->tdq_load++;
538  if ((td->td_flags & TDF_NOLOAD) == 0)
539  tdq->tdq_sysload++;
540  KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
541  SDT_PROBE2(sched, , , load__change, (int)TDQ_ID(tdq), tdq->tdq_load);
542 }
543 
544 /*
545  * Remove the load from a thread that is transitioning to a sleep state or
546  * exiting.
547  */
548 static void
549 tdq_load_rem(struct tdq *tdq, struct thread *td)
550 {
551 
552  THREAD_LOCK_ASSERT(td, MA_OWNED);
553  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
554  KASSERT(tdq->tdq_load != 0,
555  ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq)));
556 
557  tdq->tdq_load--;
558  if ((td->td_flags & TDF_NOLOAD) == 0)
559  tdq->tdq_sysload--;
560  KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
561  SDT_PROBE2(sched, , , load__change, (int)TDQ_ID(tdq), tdq->tdq_load);
562 }
563 
564 /*
565  * Bound timeshare latency by decreasing slice size as load increases. We
566  * consider the maximum latency as the sum of the threads waiting to run
567  * aside from curthread and target no more than sched_slice latency but
568  * no less than sched_slice_min runtime.
569  */
570 static inline int
571 tdq_slice(struct tdq *tdq)
572 {
573  int load;
574 
575  /*
576  * It is safe to use sys_load here because this is called from
577  * contexts where timeshare threads are running and so there
578  * cannot be higher priority load in the system.
579  */
580  load = tdq->tdq_sysload - 1;
581  if (load >= SCHED_SLICE_MIN_DIVISOR)
582  return (sched_slice_min);
583  if (load <= 1)
584  return (sched_slice);
585  return (sched_slice / load);
586 }
587 
588 /*
589  * Set lowpri to its exact value by searching the run-queue and
590  * evaluating curthread. curthread may be passed as an optimization.
591  */
592 static void
593 tdq_setlowpri(struct tdq *tdq, struct thread *ctd)
594 {
595  struct thread *td;
596 
597  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
598  if (ctd == NULL)
599  ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread;
600  td = tdq_choose(tdq);
601  if (td == NULL || td->td_priority > ctd->td_priority)
602  tdq->tdq_lowpri = ctd->td_priority;
603  else
604  tdq->tdq_lowpri = td->td_priority;
605 }
606 
607 #ifdef SMP
608 /*
609  * We need some randomness. Implement a classic Linear Congruential
610  * Generator X_{n+1}=(aX_n+c) mod m. These values are optimized for
611  * m = 2^32, a = 69069 and c = 5. We only return the upper 16 bits
612  * of the random state (in the low bits of our answer) to keep
613  * the maximum randomness.
614  */
615 static uint32_t
616 sched_random(void)
617 {
618  uint32_t *rndptr;
619 
620  rndptr = DPCPU_PTR(randomval);
621  *rndptr = *rndptr * 69069 + 5;
622 
623  return (*rndptr >> 16);
624 }
625 
626 struct cpu_search {
627  cpuset_t cs_mask;
628  u_int cs_prefer;
629  int cs_pri; /* Min priority for low. */
630  int cs_limit; /* Max load for low, min load for high. */
631  int cs_cpu;
632  int cs_load;
633 };
634 
635 #define CPU_SEARCH_LOWEST 0x1
636 #define CPU_SEARCH_HIGHEST 0x2
637 #define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST)
638 
639 #define CPUSET_FOREACH(cpu, mask) \
640  for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++) \
641  if (CPU_ISSET(cpu, &mask))
642 
643 static __always_inline int cpu_search(const struct cpu_group *cg,
644  struct cpu_search *low, struct cpu_search *high, const int match);
645 int __noinline cpu_search_lowest(const struct cpu_group *cg,
646  struct cpu_search *low);
647 int __noinline cpu_search_highest(const struct cpu_group *cg,
648  struct cpu_search *high);
649 int __noinline cpu_search_both(const struct cpu_group *cg,
650  struct cpu_search *low, struct cpu_search *high);
651 
652 /*
653  * Search the tree of cpu_groups for the lowest or highest loaded cpu
654  * according to the match argument. This routine actually compares the
655  * load on all paths through the tree and finds the least loaded cpu on
656  * the least loaded path, which may differ from the least loaded cpu in
657  * the system. This balances work among caches and busses.
658  *
659  * This inline is instantiated in three forms below using constants for the
660  * match argument. It is reduced to the minimum set for each case. It is
661  * also recursive to the depth of the tree.
662  */
663 static __always_inline int
664 cpu_search(const struct cpu_group *cg, struct cpu_search *low,
665  struct cpu_search *high, const int match)
666 {
667  struct cpu_search lgroup;
668  struct cpu_search hgroup;
669  cpuset_t cpumask;
670  struct cpu_group *child;
671  struct tdq *tdq;
672  int cpu, i, hload, lload, load, total, rnd;
673 
674  total = 0;
675  cpumask = cg->cg_mask;
676  if (match & CPU_SEARCH_LOWEST) {
677  lload = INT_MAX;
678  lgroup = *low;
679  }
680  if (match & CPU_SEARCH_HIGHEST) {
681  hload = INT_MIN;
682  hgroup = *high;
683  }
684 
685  /* Iterate through the child CPU groups and then remaining CPUs. */
686  for (i = cg->cg_children, cpu = mp_maxid; ; ) {
687  if (i == 0) {
688 #ifdef HAVE_INLINE_FFSL
689  cpu = CPU_FFS(&cpumask) - 1;
690 #else
691  while (cpu >= 0 && !CPU_ISSET(cpu, &cpumask))
692  cpu--;
693 #endif
694  if (cpu < 0)
695  break;
696  child = NULL;
697  } else
698  child = &cg->cg_child[i - 1];
699 
700  if (match & CPU_SEARCH_LOWEST)
701  lgroup.cs_cpu = -1;
702  if (match & CPU_SEARCH_HIGHEST)
703  hgroup.cs_cpu = -1;
704  if (child) { /* Handle child CPU group. */
705  CPU_NAND(&cpumask, &child->cg_mask);
706  switch (match) {
707  case CPU_SEARCH_LOWEST:
708  load = cpu_search_lowest(child, &lgroup);
709  break;
710  case CPU_SEARCH_HIGHEST:
711  load = cpu_search_highest(child, &hgroup);
712  break;
713  case CPU_SEARCH_BOTH:
714  load = cpu_search_both(child, &lgroup, &hgroup);
715  break;
716  }
717  } else { /* Handle child CPU. */
718  CPU_CLR(cpu, &cpumask);
719  tdq = TDQ_CPU(cpu);
720  load = tdq->tdq_load * 256;
721  rnd = sched_random() % 32;
722  if (match & CPU_SEARCH_LOWEST) {
723  if (cpu == low->cs_prefer)
724  load -= 64;
725  /* If that CPU is allowed and get data. */
726  if (tdq->tdq_lowpri > lgroup.cs_pri &&
727  tdq->tdq_load <= lgroup.cs_limit &&
728  CPU_ISSET(cpu, &lgroup.cs_mask)) {
729  lgroup.cs_cpu = cpu;
730  lgroup.cs_load = load - rnd;
731  }
732  }
733  if (match & CPU_SEARCH_HIGHEST)
734  if (tdq->tdq_load >= hgroup.cs_limit &&
735  tdq->tdq_transferable &&
736  CPU_ISSET(cpu, &hgroup.cs_mask)) {
737  hgroup.cs_cpu = cpu;
738  hgroup.cs_load = load - rnd;
739  }
740  }
741  total += load;
742 
743  /* We have info about child item. Compare it. */
744  if (match & CPU_SEARCH_LOWEST) {
745  if (lgroup.cs_cpu >= 0 &&
746  (load < lload ||
747  (load == lload && lgroup.cs_load < low->cs_load))) {
748  lload = load;
749  low->cs_cpu = lgroup.cs_cpu;
750  low->cs_load = lgroup.cs_load;
751  }
752  }
753  if (match & CPU_SEARCH_HIGHEST)
754  if (hgroup.cs_cpu >= 0 &&
755  (load > hload ||
756  (load == hload && hgroup.cs_load > high->cs_load))) {
757  hload = load;
758  high->cs_cpu = hgroup.cs_cpu;
759  high->cs_load = hgroup.cs_load;
760  }
761  if (child) {
762  i--;
763  if (i == 0 && CPU_EMPTY(&cpumask))
764  break;
765  }
766 #ifndef HAVE_INLINE_FFSL
767  else
768  cpu--;
769 #endif
770  }
771  return (total);
772 }
773 
774 /*
775  * cpu_search instantiations must pass constants to maintain the inline
776  * optimization.
777  */
778 int
779 cpu_search_lowest(const struct cpu_group *cg, struct cpu_search *low)
780 {
781  return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST);
782 }
783 
784 int
785 cpu_search_highest(const struct cpu_group *cg, struct cpu_search *high)
786 {
787  return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST);
788 }
789 
790 int
791 cpu_search_both(const struct cpu_group *cg, struct cpu_search *low,
792  struct cpu_search *high)
793 {
794  return cpu_search(cg, low, high, CPU_SEARCH_BOTH);
795 }
796 
797 /*
798  * Find the cpu with the least load via the least loaded path that has a
799  * lowpri greater than pri pri. A pri of -1 indicates any priority is
800  * acceptable.
801  */
802 static inline int
803 sched_lowest(const struct cpu_group *cg, cpuset_t mask, int pri, int maxload,
804  int prefer)
805 {
806  struct cpu_search low;
807 
808  low.cs_cpu = -1;
809  low.cs_prefer = prefer;
810  low.cs_mask = mask;
811  low.cs_pri = pri;
812  low.cs_limit = maxload;
813  cpu_search_lowest(cg, &low);
814  return low.cs_cpu;
815 }
816 
817 /*
818  * Find the cpu with the highest load via the highest loaded path.
819  */
820 static inline int
821 sched_highest(const struct cpu_group *cg, cpuset_t mask, int minload)
822 {
823  struct cpu_search high;
824 
825  high.cs_cpu = -1;
826  high.cs_mask = mask;
827  high.cs_limit = minload;
828  cpu_search_highest(cg, &high);
829  return high.cs_cpu;
830 }
831 
832 static void
833 sched_balance_group(struct cpu_group *cg)
834 {
835  cpuset_t hmask, lmask;
836  int high, low, anylow;
837 
838  CPU_FILL(&hmask);
839  for (;;) {
840  high = sched_highest(cg, hmask, 1);
841  /* Stop if there is no more CPU with transferrable threads. */
842  if (high == -1)
843  break;
844  CPU_CLR(high, &hmask);
845  CPU_COPY(&hmask, &lmask);
846  /* Stop if there is no more CPU left for low. */
847  if (CPU_EMPTY(&lmask))
848  break;
849  anylow = 1;
850 nextlow:
851  low = sched_lowest(cg, lmask, -1,
852  TDQ_CPU(high)->tdq_load - 1, high);
853  /* Stop if we looked well and found no less loaded CPU. */
854  if (anylow && low == -1)
855  break;
856  /* Go to next high if we found no less loaded CPU. */
857  if (low == -1)
858  continue;
859  /* Transfer thread from high to low. */
860  if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low))) {
861  /* CPU that got thread can no longer be a donor. */
862  CPU_CLR(low, &hmask);
863  } else {
864  /*
865  * If failed, then there is no threads on high
866  * that can run on this low. Drop low from low
867  * mask and look for different one.
868  */
869  CPU_CLR(low, &lmask);
870  anylow = 0;
871  goto nextlow;
872  }
873  }
874 }
875 
876 static void
877 sched_balance(void)
878 {
879  struct tdq *tdq;
880 
881  if (smp_started == 0 || rebalance == 0)
882  return;
883 
884  balance_ticks = max(balance_interval / 2, 1) +
885  (sched_random() % balance_interval);
886  tdq = TDQ_SELF();
887  TDQ_UNLOCK(tdq);
888  sched_balance_group(cpu_top);
889  TDQ_LOCK(tdq);
890 }
891 
892 /*
893  * Lock two thread queues using their address to maintain lock order.
894  */
895 static void
896 tdq_lock_pair(struct tdq *one, struct tdq *two)
897 {
898  if (one < two) {
899  TDQ_LOCK(one);
900  TDQ_LOCK_FLAGS(two, MTX_DUPOK);
901  } else {
902  TDQ_LOCK(two);
903  TDQ_LOCK_FLAGS(one, MTX_DUPOK);
904  }
905 }
906 
907 /*
908  * Unlock two thread queues. Order is not important here.
909  */
910 static void
911 tdq_unlock_pair(struct tdq *one, struct tdq *two)
912 {
913  TDQ_UNLOCK(one);
914  TDQ_UNLOCK(two);
915 }
916 
917 /*
918  * Transfer load between two imbalanced thread queues.
919  */
920 static int
921 sched_balance_pair(struct tdq *high, struct tdq *low)
922 {
923  int moved;
924  int cpu;
925 
926  tdq_lock_pair(high, low);
927  moved = 0;
928  /*
929  * Determine what the imbalance is and then adjust that to how many
930  * threads we actually have to give up (transferable).
931  */
932  if (high->tdq_transferable != 0 && high->tdq_load > low->tdq_load &&
933  (moved = tdq_move(high, low)) > 0) {
934  /*
935  * In case the target isn't the current cpu IPI it to force a
936  * reschedule with the new workload.
937  */
938  cpu = TDQ_ID(low);
939  if (cpu != PCPU_GET(cpuid))
940  ipi_cpu(cpu, IPI_PREEMPT);
941  }
942  tdq_unlock_pair(high, low);
943  return (moved);
944 }
945 
946 /*
947  * Move a thread from one thread queue to another.
948  */
949 static int
950 tdq_move(struct tdq *from, struct tdq *to)
951 {
952  struct td_sched *ts;
953  struct thread *td;
954  struct tdq *tdq;
955  int cpu;
956 
957  TDQ_LOCK_ASSERT(from, MA_OWNED);
958  TDQ_LOCK_ASSERT(to, MA_OWNED);
959 
960  tdq = from;
961  cpu = TDQ_ID(to);
962  td = tdq_steal(tdq, cpu);
963  if (td == NULL)
964  return (0);
965  ts = td->td_sched;
966  /*
967  * Although the run queue is locked the thread may be blocked. Lock
968  * it to clear this and acquire the run-queue lock.
969  */
970  thread_lock(td);
971  /* Drop recursive lock on from acquired via thread_lock(). */
972  TDQ_UNLOCK(from);
973  sched_rem(td);
974  ts->ts_cpu = cpu;
975  td->td_lock = TDQ_LOCKPTR(to);
976  tdq_add(to, td, SRQ_YIELDING);
977  return (1);
978 }
979 
980 /*
981  * This tdq has idled. Try to steal a thread from another cpu and switch
982  * to it.
983  */
984 static int
985 tdq_idled(struct tdq *tdq)
986 {
987  struct cpu_group *cg;
988  struct tdq *steal;
989  cpuset_t mask;
990  int thresh;
991  int cpu;
992 
993  if (smp_started == 0 || steal_idle == 0)
994  return (1);
995  CPU_FILL(&mask);
996  CPU_CLR(PCPU_GET(cpuid), &mask);
997  /* We don't want to be preempted while we're iterating. */
998  spinlock_enter();
999  for (cg = tdq->tdq_cg; cg != NULL; ) {
1000  if ((cg->cg_flags & CG_FLAG_THREAD) == 0)
1001  thresh = steal_thresh;
1002  else
1003  thresh = 1;
1004  cpu = sched_highest(cg, mask, thresh);
1005  if (cpu == -1) {
1006  cg = cg->cg_parent;
1007  continue;
1008  }
1009  steal = TDQ_CPU(cpu);
1010  CPU_CLR(cpu, &mask);
1011  tdq_lock_pair(tdq, steal);
1012  if (steal->tdq_load < thresh || steal->tdq_transferable == 0) {
1013  tdq_unlock_pair(tdq, steal);
1014  continue;
1015  }
1016  /*
1017  * If a thread was added while interrupts were disabled don't
1018  * steal one here. If we fail to acquire one due to affinity
1019  * restrictions loop again with this cpu removed from the
1020  * set.
1021  */
1022  if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) {
1023  tdq_unlock_pair(tdq, steal);
1024  continue;
1025  }
1026  spinlock_exit();
1027  TDQ_UNLOCK(steal);
1028  mi_switch(SW_VOL | SWT_IDLE, NULL);
1029  thread_unlock(curthread);
1030 
1031  return (0);
1032  }
1033  spinlock_exit();
1034  return (1);
1035 }
1036 
1037 /*
1038  * Notify a remote cpu of new work. Sends an IPI if criteria are met.
1039  */
1040 static void
1041 tdq_notify(struct tdq *tdq, struct thread *td)
1042 {
1043  struct thread *ctd;
1044  int pri;
1045  int cpu;
1046 
1047  if (tdq->tdq_ipipending)
1048  return;
1049  cpu = td->td_sched->ts_cpu;
1050  pri = td->td_priority;
1051  ctd = pcpu_find(cpu)->pc_curthread;
1052  if (!sched_shouldpreempt(pri, ctd->td_priority, 1))
1053  return;
1054 
1055  /*
1056  * Make sure that our caller's earlier update to tdq_load is
1057  * globally visible before we read tdq_cpu_idle. Idle thread
1058  * accesses both of them without locks, and the order is important.
1059  */
1060  atomic_thread_fence_seq_cst();
1061 
1062  if (TD_IS_IDLETHREAD(ctd)) {
1063  /*
1064  * If the MD code has an idle wakeup routine try that before
1065  * falling back to IPI.
1066  */
1067  if (!tdq->tdq_cpu_idle || cpu_idle_wakeup(cpu))
1068  return;
1069  }
1070  tdq->tdq_ipipending = 1;
1071  ipi_cpu(cpu, IPI_PREEMPT);
1072 }
1073 
1074 /*
1075  * Steals load from a timeshare queue. Honors the rotating queue head
1076  * index.
1077  */
1078 static struct thread *
1079 runq_steal_from(struct runq *rq, int cpu, u_char start)
1080 {
1081  struct rqbits *rqb;
1082  struct rqhead *rqh;
1083  struct thread *td, *first;
1084  int bit;
1085  int i;
1086 
1087  rqb = &rq->rq_status;
1088  bit = start & (RQB_BPW -1);
1089  first = NULL;
1090 again:
1091  for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) {
1092  if (rqb->rqb_bits[i] == 0)
1093  continue;
1094  if (bit == 0)
1095  bit = RQB_FFS(rqb->rqb_bits[i]);
1096  for (; bit < RQB_BPW; bit++) {
1097  if ((rqb->rqb_bits[i] & (1ul << bit)) == 0)
1098  continue;
1099  rqh = &rq->rq_queues[bit + (i << RQB_L2BPW)];
1100  TAILQ_FOREACH(td, rqh, td_runq) {
1101  if (first && THREAD_CAN_MIGRATE(td) &&
1102  THREAD_CAN_SCHED(td, cpu))
1103  return (td);
1104  first = td;
1105  }
1106  }
1107  }
1108  if (start != 0) {
1109  start = 0;
1110  goto again;
1111  }
1112 
1113  if (first && THREAD_CAN_MIGRATE(first) &&
1114  THREAD_CAN_SCHED(first, cpu))
1115  return (first);
1116  return (NULL);
1117 }
1118 
1119 /*
1120  * Steals load from a standard linear queue.
1121  */
1122 static struct thread *
1123 runq_steal(struct runq *rq, int cpu)
1124 {
1125  struct rqhead *rqh;
1126  struct rqbits *rqb;
1127  struct thread *td;
1128  int word;
1129  int bit;
1130 
1131  rqb = &rq->rq_status;
1132  for (word = 0; word < RQB_LEN; word++) {
1133  if (rqb->rqb_bits[word] == 0)
1134  continue;
1135  for (bit = 0; bit < RQB_BPW; bit++) {
1136  if ((rqb->rqb_bits[word] & (1ul << bit)) == 0)
1137  continue;
1138  rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)];
1139  TAILQ_FOREACH(td, rqh, td_runq)
1140  if (THREAD_CAN_MIGRATE(td) &&
1141  THREAD_CAN_SCHED(td, cpu))
1142  return (td);
1143  }
1144  }
1145  return (NULL);
1146 }
1147 
1148 /*
1149  * Attempt to steal a thread in priority order from a thread queue.
1150  */
1151 static struct thread *
1152 tdq_steal(struct tdq *tdq, int cpu)
1153 {
1154  struct thread *td;
1155 
1156  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1157  if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL)
1158  return (td);
1159  if ((td = runq_steal_from(&tdq->tdq_timeshare,
1160  cpu, tdq->tdq_ridx)) != NULL)
1161  return (td);
1162  return (runq_steal(&tdq->tdq_idle, cpu));
1163 }
1164 
1165 /*
1166  * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the
1167  * current lock and returns with the assigned queue locked.
1168  */
1169 static inline struct tdq *
1170 sched_setcpu(struct thread *td, int cpu, int flags)
1171 {
1172 
1173  struct tdq *tdq;
1174 
1175  THREAD_LOCK_ASSERT(td, MA_OWNED);
1176  tdq = TDQ_CPU(cpu);
1177  td->td_sched->ts_cpu = cpu;
1178  /*
1179  * If the lock matches just return the queue.
1180  */
1181  if (td->td_lock == TDQ_LOCKPTR(tdq))
1182  return (tdq);
1183 #ifdef notyet
1184  /*
1185  * If the thread isn't running its lockptr is a
1186  * turnstile or a sleepqueue. We can just lock_set without
1187  * blocking.
1188  */
1189  if (TD_CAN_RUN(td)) {
1190  TDQ_LOCK(tdq);
1191  thread_lock_set(td, TDQ_LOCKPTR(tdq));
1192  return (tdq);
1193  }
1194 #endif
1195  /*
1196  * The hard case, migration, we need to block the thread first to
1197  * prevent order reversals with other cpus locks.
1198  */
1199  spinlock_enter();
1200  thread_lock_block(td);
1201  TDQ_LOCK(tdq);
1202  thread_lock_unblock(td, TDQ_LOCKPTR(tdq));
1203  spinlock_exit();
1204  return (tdq);
1205 }
1206 
1207 SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding");
1208 SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity");
1209 SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity");
1210 SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load");
1211 SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu");
1212 SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration");
1213 
1214 static int
1215 sched_pickcpu(struct thread *td, int flags)
1216 {
1217  struct cpu_group *cg, *ccg;
1218  struct td_sched *ts;
1219  struct tdq *tdq;
1220  cpuset_t mask;
1221  int cpu, pri, self;
1222 
1223  self = PCPU_GET(cpuid);
1224  ts = td->td_sched;
1225  if (smp_started == 0)
1226  return (self);
1227  /*
1228  * Don't migrate a running thread from sched_switch().
1229  */
1230  if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td))
1231  return (ts->ts_cpu);
1232  /*
1233  * Prefer to run interrupt threads on the processors that generate
1234  * the interrupt.
1235  */
1236  pri = td->td_priority;
1237  if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) &&
1238  curthread->td_intr_nesting_level && ts->ts_cpu != self) {
1239  SCHED_STAT_INC(pickcpu_intrbind);
1240  ts->ts_cpu = self;
1241  if (TDQ_CPU(self)->tdq_lowpri > pri) {
1242  SCHED_STAT_INC(pickcpu_affinity);
1243  return (ts->ts_cpu);
1244  }
1245  }
1246  /*
1247  * If the thread can run on the last cpu and the affinity has not
1248  * expired or it is idle run it there.
1249  */
1250  tdq = TDQ_CPU(ts->ts_cpu);
1251  cg = tdq->tdq_cg;
1252  if (THREAD_CAN_SCHED(td, ts->ts_cpu) &&
1253  tdq->tdq_lowpri >= PRI_MIN_IDLE &&
1254  SCHED_AFFINITY(ts, CG_SHARE_L2)) {
1255  if (cg->cg_flags & CG_FLAG_THREAD) {
1256  CPUSET_FOREACH(cpu, cg->cg_mask) {
1257  if (TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE)
1258  break;
1259  }
1260  } else
1261  cpu = INT_MAX;
1262  if (cpu > mp_maxid) {
1263  SCHED_STAT_INC(pickcpu_idle_affinity);
1264  return (ts->ts_cpu);
1265  }
1266  }
1267  /*
1268  * Search for the last level cache CPU group in the tree.
1269  * Skip caches with expired affinity time and SMT groups.
1270  * Affinity to higher level caches will be handled less aggressively.
1271  */
1272  for (ccg = NULL; cg != NULL; cg = cg->cg_parent) {
1273  if (cg->cg_flags & CG_FLAG_THREAD)
1274  continue;
1275  if (!SCHED_AFFINITY(ts, cg->cg_level))
1276  continue;
1277  ccg = cg;
1278  }
1279  if (ccg != NULL)
1280  cg = ccg;
1281  cpu = -1;
1282  /* Search the group for the less loaded idle CPU we can run now. */
1283  mask = td->td_cpuset->cs_mask;
1284  if (cg != NULL && cg != cpu_top &&
1285  CPU_CMP(&cg->cg_mask, &cpu_top->cg_mask) != 0)
1286  cpu = sched_lowest(cg, mask, max(pri, PRI_MAX_TIMESHARE),
1287  INT_MAX, ts->ts_cpu);
1288  /* Search globally for the less loaded CPU we can run now. */
1289  if (cpu == -1)
1290  cpu = sched_lowest(cpu_top, mask, pri, INT_MAX, ts->ts_cpu);
1291  /* Search globally for the less loaded CPU. */
1292  if (cpu == -1)
1293  cpu = sched_lowest(cpu_top, mask, -1, INT_MAX, ts->ts_cpu);
1294  KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu."));
1295  /*
1296  * Compare the lowest loaded cpu to current cpu.
1297  */
1298  if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri &&
1299  TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE &&
1300  TDQ_CPU(self)->tdq_load <= TDQ_CPU(cpu)->tdq_load + 1) {
1301  SCHED_STAT_INC(pickcpu_local);
1302  cpu = self;
1303  } else
1304  SCHED_STAT_INC(pickcpu_lowest);
1305  if (cpu != ts->ts_cpu)
1306  SCHED_STAT_INC(pickcpu_migration);
1307  return (cpu);
1308 }
1309 #endif
1310 
1311 /*
1312  * Pick the highest priority task we have and return it.
1313  */
1314 static struct thread *
1315 tdq_choose(struct tdq *tdq)
1316 {
1317  struct thread *td;
1318 
1319  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1320  td = runq_choose(&tdq->tdq_realtime);
1321  if (td != NULL)
1322  return (td);
1323  td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx);
1324  if (td != NULL) {
1325  KASSERT(td->td_priority >= PRI_MIN_BATCH,
1326  ("tdq_choose: Invalid priority on timeshare queue %d",
1327  td->td_priority));
1328  return (td);
1329  }
1330  td = runq_choose(&tdq->tdq_idle);
1331  if (td != NULL) {
1332  KASSERT(td->td_priority >= PRI_MIN_IDLE,
1333  ("tdq_choose: Invalid priority on idle queue %d",
1334  td->td_priority));
1335  return (td);
1336  }
1337 
1338  return (NULL);
1339 }
1340 
1341 /*
1342  * Initialize a thread queue.
1343  */
1344 static void
1345 tdq_setup(struct tdq *tdq)
1346 {
1347 
1348  if (bootverbose)
1349  printf("ULE: setup cpu %d\n", TDQ_ID(tdq));
1350  runq_init(&tdq->tdq_realtime);
1351  runq_init(&tdq->tdq_timeshare);
1352  runq_init(&tdq->tdq_idle);
1353  snprintf(tdq->tdq_name, sizeof(tdq->tdq_name),
1354  "sched lock %d", (int)TDQ_ID(tdq));
1355  mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock",
1356  MTX_SPIN | MTX_RECURSE);
1357 #ifdef KTR
1358  snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname),
1359  "CPU %d load", (int)TDQ_ID(tdq));
1360 #endif
1361 }
1362 
1363 #ifdef SMP
1364 static void
1365 sched_setup_smp(void)
1366 {
1367  struct tdq *tdq;
1368  int i;
1369 
1370  cpu_top = smp_topo();
1371  CPU_FOREACH(i) {
1372  tdq = TDQ_CPU(i);
1373  tdq_setup(tdq);
1374  tdq->tdq_cg = smp_topo_find(cpu_top, i);
1375  if (tdq->tdq_cg == NULL)
1376  panic("Can't find cpu group for %d\n", i);
1377  }
1378  balance_tdq = TDQ_SELF();
1379  sched_balance();
1380 }
1381 #endif
1382 
1383 /*
1384  * Setup the thread queues and initialize the topology based on MD
1385  * information.
1386  */
1387 static void
1389 {
1390  struct tdq *tdq;
1391 
1392  tdq = TDQ_SELF();
1393 #ifdef SMP
1394  sched_setup_smp();
1395 #else
1396  tdq_setup(tdq);
1397 #endif
1398 
1399  /* Add thread0's load since it's running. */
1400  TDQ_LOCK(tdq);
1401  thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF());
1402  tdq_load_add(tdq, &thread0);
1403  tdq->tdq_lowpri = thread0.td_priority;
1404  TDQ_UNLOCK(tdq);
1405 }
1406 
1407 /*
1408  * This routine determines time constants after stathz and hz are setup.
1409  */
1410 /* ARGSUSED */
1411 static void
1413 {
1414  int incr;
1415 
1416  realstathz = stathz ? stathz : hz;
1419  hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
1420  realstathz);
1421 
1422  /*
1423  * tickincr is shifted out by 10 to avoid rounding errors due to
1424  * hz not being evenly divisible by stathz on all platforms.
1425  */
1426  incr = (hz << SCHED_TICK_SHIFT) / realstathz;
1427  /*
1428  * This does not work for values of stathz that are more than
1429  * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen.
1430  */
1431  if (incr == 0)
1432  incr = 1;
1433  tickincr = incr;
1434 #ifdef SMP
1435  /*
1436  * Set the default balance interval now that we know
1437  * what realstathz is.
1438  */
1439  balance_interval = realstathz;
1440  affinity = SCHED_AFFINITY_DEFAULT;
1441 #endif
1442  if (sched_idlespinthresh < 0)
1443  sched_idlespinthresh = 2 * max(10000, 6 * hz) / realstathz;
1444 }
1445 
1446 
1447 /*
1448  * This is the core of the interactivity algorithm. Determines a score based
1449  * on past behavior. It is the ratio of sleep time to run time scaled to
1450  * a [0, 100] integer. This is the voluntary sleep time of a process, which
1451  * differs from the cpu usage because it does not account for time spent
1452  * waiting on a run-queue. Would be prettier if we had floating point.
1453  */
1454 static int
1455 sched_interact_score(struct thread *td)
1456 {
1457  struct td_sched *ts;
1458  int div;
1459 
1460  ts = td->td_sched;
1461  /*
1462  * The score is only needed if this is likely to be an interactive
1463  * task. Don't go through the expense of computing it if there's
1464  * no chance.
1465  */
1467  ts->ts_runtime >= ts->ts_slptime)
1468  return (SCHED_INTERACT_HALF);
1469 
1470  if (ts->ts_runtime > ts->ts_slptime) {
1471  div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF);
1472  return (SCHED_INTERACT_HALF +
1473  (SCHED_INTERACT_HALF - (ts->ts_slptime / div)));
1474  }
1475  if (ts->ts_slptime > ts->ts_runtime) {
1476  div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF);
1477  return (ts->ts_runtime / div);
1478  }
1479  /* runtime == slptime */
1480  if (ts->ts_runtime)
1481  return (SCHED_INTERACT_HALF);
1482 
1483  /*
1484  * This can happen if slptime and runtime are 0.
1485  */
1486  return (0);
1487 
1488 }
1489 
1490 /*
1491  * Scale the scheduling priority according to the "interactivity" of this
1492  * process.
1493  */
1494 static void
1495 sched_priority(struct thread *td)
1496 {
1497  int score;
1498  int pri;
1499 
1500  if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
1501  return;
1502  /*
1503  * If the score is interactive we place the thread in the realtime
1504  * queue with a priority that is less than kernel and interrupt
1505  * priorities. These threads are not subject to nice restrictions.
1506  *
1507  * Scores greater than this are placed on the normal timeshare queue
1508  * where the priority is partially decided by the most recent cpu
1509  * utilization and the rest is decided by nice value.
1510  *
1511  * The nice value of the process has a linear effect on the calculated
1512  * score. Negative nice values make it easier for a thread to be
1513  * considered interactive.
1514  */
1515  score = imax(0, sched_interact_score(td) + td->td_proc->p_nice);
1516  if (score < sched_interact) {
1517  pri = PRI_MIN_INTERACT;
1518  pri += ((PRI_MAX_INTERACT - PRI_MIN_INTERACT + 1) /
1519  sched_interact) * score;
1520  KASSERT(pri >= PRI_MIN_INTERACT && pri <= PRI_MAX_INTERACT,
1521  ("sched_priority: invalid interactive priority %d score %d",
1522  pri, score));
1523  } else {
1524  pri = SCHED_PRI_MIN;
1525  if (td->td_sched->ts_ticks)
1526  pri += min(SCHED_PRI_TICKS(td->td_sched),
1527  SCHED_PRI_RANGE - 1);
1528  pri += SCHED_PRI_NICE(td->td_proc->p_nice);
1529  KASSERT(pri >= PRI_MIN_BATCH && pri <= PRI_MAX_BATCH,
1530  ("sched_priority: invalid priority %d: nice %d, "
1531  "ticks %d ftick %d ltick %d tick pri %d",
1532  pri, td->td_proc->p_nice, td->td_sched->ts_ticks,
1533  td->td_sched->ts_ftick, td->td_sched->ts_ltick,
1534  SCHED_PRI_TICKS(td->td_sched)));
1535  }
1536  sched_user_prio(td, pri);
1537 
1538  return;
1539 }
1540 
1541 /*
1542  * This routine enforces a maximum limit on the amount of scheduling history
1543  * kept. It is called after either the slptime or runtime is adjusted. This
1544  * function is ugly due to integer math.
1545  */
1546 static void
1547 sched_interact_update(struct thread *td)
1548 {
1549  struct td_sched *ts;
1550  u_int sum;
1551 
1552  ts = td->td_sched;
1553  sum = ts->ts_runtime + ts->ts_slptime;
1554  if (sum < SCHED_SLP_RUN_MAX)
1555  return;
1556  /*
1557  * This only happens from two places:
1558  * 1) We have added an unusual amount of run time from fork_exit.
1559  * 2) We have added an unusual amount of sleep time from sched_sleep().
1560  */
1561  if (sum > SCHED_SLP_RUN_MAX * 2) {
1562  if (ts->ts_runtime > ts->ts_slptime) {
1564  ts->ts_slptime = 1;
1565  } else {
1567  ts->ts_runtime = 1;
1568  }
1569  return;
1570  }
1571  /*
1572  * If we have exceeded by more than 1/5th then the algorithm below
1573  * will not bring us back into range. Dividing by two here forces
1574  * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX]
1575  */
1576  if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) {
1577  ts->ts_runtime /= 2;
1578  ts->ts_slptime /= 2;
1579  return;
1580  }
1581  ts->ts_runtime = (ts->ts_runtime / 5) * 4;
1582  ts->ts_slptime = (ts->ts_slptime / 5) * 4;
1583 }
1584 
1585 /*
1586  * Scale back the interactivity history when a child thread is created. The
1587  * history is inherited from the parent but the thread may behave totally
1588  * differently. For example, a shell spawning a compiler process. We want
1589  * to learn that the compiler is behaving badly very quickly.
1590  */
1591 static void
1592 sched_interact_fork(struct thread *td)
1593 {
1594  int ratio;
1595  int sum;
1596 
1597  sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime;
1598  if (sum > SCHED_SLP_RUN_FORK) {
1599  ratio = sum / SCHED_SLP_RUN_FORK;
1600  td->td_sched->ts_runtime /= ratio;
1601  td->td_sched->ts_slptime /= ratio;
1602  }
1603 }
1604 
1605 /*
1606  * Called from proc0_init() to setup the scheduler fields.
1607  */
1608 void
1610 {
1611 
1612  /*
1613  * Set up the scheduler specific parts of proc0.
1614  */
1615  proc0.p_sched = NULL; /* XXX */
1616  thread0.td_sched = &td_sched0;
1619  td_sched0.ts_slice = 0;
1620 }
1621 
1622 /*
1623  * This is only somewhat accurate since given many processes of the same
1624  * priority they will switch when their slices run out, which will be
1625  * at most sched_slice stathz ticks.
1626  */
1627 int
1629 {
1630 
1631  /* Convert sched_slice from stathz to hz. */
1632  return (imax(1, (sched_slice * hz + realstathz / 2) / realstathz));
1633 }
1634 
1635 /*
1636  * Update the percent cpu tracking information when it is requested or
1637  * the total history exceeds the maximum. We keep a sliding history of
1638  * tick counts that slowly decays. This is less precise than the 4BSD
1639  * mechanism since it happens with less regular and frequent events.
1640  */
1641 static void
1642 sched_pctcpu_update(struct td_sched *ts, int run)
1643 {
1644  int t = ticks;
1645 
1646  if (t - ts->ts_ltick >= SCHED_TICK_TARG) {
1647  ts->ts_ticks = 0;
1648  ts->ts_ftick = t - SCHED_TICK_TARG;
1649  } else if (t - ts->ts_ftick >= SCHED_TICK_MAX) {
1650  ts->ts_ticks = (ts->ts_ticks / (ts->ts_ltick - ts->ts_ftick)) *
1651  (ts->ts_ltick - (t - SCHED_TICK_TARG));
1652  ts->ts_ftick = t - SCHED_TICK_TARG;
1653  }
1654  if (run)
1655  ts->ts_ticks += (t - ts->ts_ltick) << SCHED_TICK_SHIFT;
1656  ts->ts_ltick = t;
1657 }
1658 
1659 /*
1660  * Adjust the priority of a thread. Move it to the appropriate run-queue
1661  * if necessary. This is the back-end for several priority related
1662  * functions.
1663  */
1664 static void
1665 sched_thread_priority(struct thread *td, u_char prio)
1666 {
1667  struct td_sched *ts;
1668  struct tdq *tdq;
1669  int oldpri;
1670 
1671  KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio",
1672  "prio:%d", td->td_priority, "new prio:%d", prio,
1673  KTR_ATTR_LINKED, sched_tdname(curthread));
1674  SDT_PROBE3(sched, , , change__pri, td, td->td_proc, prio);
1675  if (td != curthread && prio < td->td_priority) {
1676  KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread),
1677  "lend prio", "prio:%d", td->td_priority, "new prio:%d",
1678  prio, KTR_ATTR_LINKED, sched_tdname(td));
1679  SDT_PROBE4(sched, , , lend__pri, td, td->td_proc, prio,
1680  curthread);
1681  }
1682  ts = td->td_sched;
1683  THREAD_LOCK_ASSERT(td, MA_OWNED);
1684  if (td->td_priority == prio)
1685  return;
1686  /*
1687  * If the priority has been elevated due to priority
1688  * propagation, we may have to move ourselves to a new
1689  * queue. This could be optimized to not re-add in some
1690  * cases.
1691  */
1692  if (TD_ON_RUNQ(td) && prio < td->td_priority) {
1693  sched_rem(td);
1694  td->td_priority = prio;
1695  sched_add(td, SRQ_BORROWING);
1696  return;
1697  }
1698  /*
1699  * If the thread is currently running we may have to adjust the lowpri
1700  * information so other cpus are aware of our current priority.
1701  */
1702  if (TD_IS_RUNNING(td)) {
1703  tdq = TDQ_CPU(ts->ts_cpu);
1704  oldpri = td->td_priority;
1705  td->td_priority = prio;
1706  if (prio < tdq->tdq_lowpri)
1707  tdq->tdq_lowpri = prio;
1708  else if (tdq->tdq_lowpri == oldpri)
1709  tdq_setlowpri(tdq, td);
1710  return;
1711  }
1712  td->td_priority = prio;
1713 }
1714 
1715 /*
1716  * Update a thread's priority when it is lent another thread's
1717  * priority.
1718  */
1719 void
1720 sched_lend_prio(struct thread *td, u_char prio)
1721 {
1722 
1723  td->td_flags |= TDF_BORROWING;
1724  sched_thread_priority(td, prio);
1725 }
1726 
1727 /*
1728  * Restore a thread's priority when priority propagation is
1729  * over. The prio argument is the minimum priority the thread
1730  * needs to have to satisfy other possible priority lending
1731  * requests. If the thread's regular priority is less
1732  * important than prio, the thread will keep a priority boost
1733  * of prio.
1734  */
1735 void
1736 sched_unlend_prio(struct thread *td, u_char prio)
1737 {
1738  u_char base_pri;
1739 
1740  if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
1741  td->td_base_pri <= PRI_MAX_TIMESHARE)
1742  base_pri = td->td_user_pri;
1743  else
1744  base_pri = td->td_base_pri;
1745  if (prio >= base_pri) {
1746  td->td_flags &= ~TDF_BORROWING;
1747  sched_thread_priority(td, base_pri);
1748  } else
1749  sched_lend_prio(td, prio);
1750 }
1751 
1752 /*
1753  * Standard entry for setting the priority to an absolute value.
1754  */
1755 void
1756 sched_prio(struct thread *td, u_char prio)
1757 {
1758  u_char oldprio;
1759 
1760  /* First, update the base priority. */
1761  td->td_base_pri = prio;
1762 
1763  /*
1764  * If the thread is borrowing another thread's priority, don't
1765  * ever lower the priority.
1766  */
1767  if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
1768  return;
1769 
1770  /* Change the real priority. */
1771  oldprio = td->td_priority;
1772  sched_thread_priority(td, prio);
1773 
1774  /*
1775  * If the thread is on a turnstile, then let the turnstile update
1776  * its state.
1777  */
1778  if (TD_ON_LOCK(td) && oldprio != prio)
1779  turnstile_adjust(td, oldprio);
1780 }
1781 
1782 /*
1783  * Set the base user priority, does not effect current running priority.
1784  */
1785 void
1786 sched_user_prio(struct thread *td, u_char prio)
1787 {
1788 
1789  td->td_base_user_pri = prio;
1790  if (td->td_lend_user_pri <= prio)
1791  return;
1792  td->td_user_pri = prio;
1793 }
1794 
1795 void
1796 sched_lend_user_prio(struct thread *td, u_char prio)
1797 {
1798 
1799  THREAD_LOCK_ASSERT(td, MA_OWNED);
1800  td->td_lend_user_pri = prio;
1801  td->td_user_pri = min(prio, td->td_base_user_pri);
1802  if (td->td_priority > td->td_user_pri)
1803  sched_prio(td, td->td_user_pri);
1804  else if (td->td_priority != td->td_user_pri)
1805  td->td_flags |= TDF_NEEDRESCHED;
1806 }
1807 
1808 /*
1809  * Handle migration from sched_switch(). This happens only for
1810  * cpu binding.
1811  */
1812 static struct mtx *
1813 sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags)
1814 {
1815  struct tdq *tdn;
1816 
1817  tdn = TDQ_CPU(td->td_sched->ts_cpu);
1818 #ifdef SMP
1819  tdq_load_rem(tdq, td);
1820  /*
1821  * Do the lock dance required to avoid LOR. We grab an extra
1822  * spinlock nesting to prevent preemption while we're
1823  * not holding either run-queue lock.
1824  */
1825  spinlock_enter();
1826  thread_lock_block(td); /* This releases the lock on tdq. */
1827 
1828  /*
1829  * Acquire both run-queue locks before placing the thread on the new
1830  * run-queue to avoid deadlocks created by placing a thread with a
1831  * blocked lock on the run-queue of a remote processor. The deadlock
1832  * occurs when a third processor attempts to lock the two queues in
1833  * question while the target processor is spinning with its own
1834  * run-queue lock held while waiting for the blocked lock to clear.
1835  */
1836  tdq_lock_pair(tdn, tdq);
1837  tdq_add(tdn, td, flags);
1838  tdq_notify(tdn, td);
1839  TDQ_UNLOCK(tdn);
1840  spinlock_exit();
1841 #endif
1842  return (TDQ_LOCKPTR(tdn));
1843 }
1844 
1845 /*
1846  * Variadic version of thread_lock_unblock() that does not assume td_lock
1847  * is blocked.
1848  */
1849 static inline void
1850 thread_unblock_switch(struct thread *td, struct mtx *mtx)
1851 {
1852  atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock,
1853  (uintptr_t)mtx);
1854 }
1855 
1856 /*
1857  * Switch threads. This function has to handle threads coming in while
1858  * blocked for some reason, running, or idle. It also must deal with
1859  * migrating a thread from one queue to another as running threads may
1860  * be assigned elsewhere via binding.
1861  */
1862 void
1863 sched_switch(struct thread *td, struct thread *newtd, int flags)
1864 {
1865  struct tdq *tdq;
1866  struct td_sched *ts;
1867  struct mtx *mtx;
1868  int srqflag;
1869  int cpuid, preempted;
1870 
1871  THREAD_LOCK_ASSERT(td, MA_OWNED);
1872  KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument"));
1873 
1874  cpuid = PCPU_GET(cpuid);
1875  tdq = TDQ_CPU(cpuid);
1876  ts = td->td_sched;
1877  mtx = td->td_lock;
1878  sched_pctcpu_update(ts, 1);
1879  ts->ts_rltick = ticks;
1880  td->td_lastcpu = td->td_oncpu;
1881  td->td_oncpu = NOCPU;
1882  preempted = !((td->td_flags & TDF_SLICEEND) ||
1883  (flags & SWT_RELINQUISH));
1884  td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND);
1885  td->td_owepreempt = 0;
1886  if (!TD_IS_IDLETHREAD(td))
1887  tdq->tdq_switchcnt++;
1888  /*
1889  * The lock pointer in an idle thread should never change. Reset it
1890  * to CAN_RUN as well.
1891  */
1892  if (TD_IS_IDLETHREAD(td)) {
1893  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1894  TD_SET_CAN_RUN(td);
1895  } else if (TD_IS_RUNNING(td)) {
1896  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1897  srqflag = preempted ?
1898  SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
1899  SRQ_OURSELF|SRQ_YIELDING;
1900 #ifdef SMP
1901  if (THREAD_CAN_MIGRATE(td) && !THREAD_CAN_SCHED(td, ts->ts_cpu))
1902  ts->ts_cpu = sched_pickcpu(td, 0);
1903 #endif
1904  if (ts->ts_cpu == cpuid)
1905  tdq_runq_add(tdq, td, srqflag);
1906  else {
1907  KASSERT(THREAD_CAN_MIGRATE(td) ||
1908  (ts->ts_flags & TSF_BOUND) != 0,
1909  ("Thread %p shouldn't migrate", td));
1910  mtx = sched_switch_migrate(tdq, td, srqflag);
1911  }
1912  } else {
1913  /* This thread must be going to sleep. */
1914  TDQ_LOCK(tdq);
1915  mtx = thread_lock_block(td);
1916  tdq_load_rem(tdq, td);
1917  }
1918  /*
1919  * We enter here with the thread blocked and assigned to the
1920  * appropriate cpu run-queue or sleep-queue and with the current
1921  * thread-queue locked.
1922  */
1923  TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
1924  newtd = choosethread();
1925  /*
1926  * Call the MD code to switch contexts if necessary.
1927  */
1928  if (td != newtd) {
1929 #ifdef HWPMC_HOOKS
1930  if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1931  PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
1932 #endif
1933  SDT_PROBE2(sched, , , off__cpu, newtd, newtd->td_proc);
1934  lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
1935  TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
1936  sched_pctcpu_update(newtd->td_sched, 0);
1937 
1938 #ifdef KDTRACE_HOOKS
1939  /*
1940  * If DTrace has set the active vtime enum to anything
1941  * other than INACTIVE (0), then it should have set the
1942  * function to call.
1943  */
1944  if (dtrace_vtime_active)
1945  (*dtrace_vtime_switch_func)(newtd);
1946 #endif
1947 
1948  cpu_switch(td, newtd, mtx);
1949  /*
1950  * We may return from cpu_switch on a different cpu. However,
1951  * we always return with td_lock pointing to the current cpu's
1952  * run queue lock.
1953  */
1954  cpuid = PCPU_GET(cpuid);
1955  tdq = TDQ_CPU(cpuid);
1956  lock_profile_obtain_lock_success(
1957  &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
1958 
1959  SDT_PROBE0(sched, , , on__cpu);
1960 #ifdef HWPMC_HOOKS
1961  if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1962  PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
1963 #endif
1964  } else {
1965  thread_unblock_switch(td, mtx);
1966  SDT_PROBE0(sched, , , remain__cpu);
1967  }
1968  /*
1969  * Assert that all went well and return.
1970  */
1971  TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED);
1972  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1973  td->td_oncpu = cpuid;
1974 }
1975 
1976 /*
1977  * Adjust thread priorities as a result of a nice request.
1978  */
1979 void
1980 sched_nice(struct proc *p, int nice)
1981 {
1982  struct thread *td;
1983 
1984  PROC_LOCK_ASSERT(p, MA_OWNED);
1985 
1986  p->p_nice = nice;
1987  FOREACH_THREAD_IN_PROC(p, td) {
1988  thread_lock(td);
1989  sched_priority(td);
1990  sched_prio(td, td->td_base_user_pri);
1991  thread_unlock(td);
1992  }
1993 }
1994 
1995 /*
1996  * Record the sleep time for the interactivity scorer.
1997  */
1998 void
1999 sched_sleep(struct thread *td, int prio)
2000 {
2001 
2002  THREAD_LOCK_ASSERT(td, MA_OWNED);
2003 
2004  td->td_slptick = ticks;
2005  if (TD_IS_SUSPENDED(td) || prio >= PSOCK)
2006  td->td_flags |= TDF_CANSWAP;
2007  if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
2008  return;
2009  if (static_boost == 1 && prio)
2010  sched_prio(td, prio);
2011  else if (static_boost && td->td_priority > static_boost)
2012  sched_prio(td, static_boost);
2013 }
2014 
2015 /*
2016  * Schedule a thread to resume execution and record how long it voluntarily
2017  * slept. We also update the pctcpu, interactivity, and priority.
2018  */
2019 void
2020 sched_wakeup(struct thread *td)
2021 {
2022  struct td_sched *ts;
2023  int slptick;
2024 
2025  THREAD_LOCK_ASSERT(td, MA_OWNED);
2026  ts = td->td_sched;
2027  td->td_flags &= ~TDF_CANSWAP;
2028  /*
2029  * If we slept for more than a tick update our interactivity and
2030  * priority.
2031  */
2032  slptick = td->td_slptick;
2033  td->td_slptick = 0;
2034  if (slptick && slptick != ticks) {
2035  ts->ts_slptime += (ticks - slptick) << SCHED_TICK_SHIFT;
2037  sched_pctcpu_update(ts, 0);
2038  }
2039  /*
2040  * Reset the slice value since we slept and advanced the round-robin.
2041  */
2042  ts->ts_slice = 0;
2043  sched_add(td, SRQ_BORING);
2044 }
2045 
2046 /*
2047  * Penalize the parent for creating a new child and initialize the child's
2048  * priority.
2049  */
2050 void
2051 sched_fork(struct thread *td, struct thread *child)
2052 {
2053  THREAD_LOCK_ASSERT(td, MA_OWNED);
2054  sched_pctcpu_update(td->td_sched, 1);
2055  sched_fork_thread(td, child);
2056  /*
2057  * Penalize the parent and child for forking.
2058  */
2059  sched_interact_fork(child);
2060  sched_priority(child);
2061  td->td_sched->ts_runtime += tickincr;
2063  sched_priority(td);
2064 }
2065 
2066 /*
2067  * Fork a new thread, may be within the same process.
2068  */
2069 void
2070 sched_fork_thread(struct thread *td, struct thread *child)
2071 {
2072  struct td_sched *ts;
2073  struct td_sched *ts2;
2074  struct tdq *tdq;
2075 
2076  tdq = TDQ_SELF();
2077  THREAD_LOCK_ASSERT(td, MA_OWNED);
2078  /*
2079  * Initialize child.
2080  */
2081  ts = td->td_sched;
2082  ts2 = child->td_sched;
2083  child->td_lock = TDQ_LOCKPTR(tdq);
2084  child->td_cpuset = cpuset_ref(td->td_cpuset);
2085  ts2->ts_cpu = ts->ts_cpu;
2086  ts2->ts_flags = 0;
2087  /*
2088  * Grab our parents cpu estimation information.
2089  */
2090  ts2->ts_ticks = ts->ts_ticks;
2091  ts2->ts_ltick = ts->ts_ltick;
2092  ts2->ts_ftick = ts->ts_ftick;
2093  /*
2094  * Do not inherit any borrowed priority from the parent.
2095  */
2096  child->td_priority = child->td_base_pri;
2097  /*
2098  * And update interactivity score.
2099  */
2100  ts2->ts_slptime = ts->ts_slptime;
2101  ts2->ts_runtime = ts->ts_runtime;
2102  /* Attempt to quickly learn interactivity. */
2103  ts2->ts_slice = tdq_slice(tdq) - sched_slice_min;
2104 #ifdef KTR
2105  bzero(ts2->ts_name, sizeof(ts2->ts_name));
2106 #endif
2107 }
2108 
2109 /*
2110  * Adjust the priority class of a thread.
2111  */
2112 void
2113 sched_class(struct thread *td, int class)
2114 {
2115 
2116  THREAD_LOCK_ASSERT(td, MA_OWNED);
2117  if (td->td_pri_class == class)
2118  return;
2119  td->td_pri_class = class;
2120 }
2121 
2122 /*
2123  * Return some of the child's priority and interactivity to the parent.
2124  */
2125 void
2126 sched_exit(struct proc *p, struct thread *child)
2127 {
2128  struct thread *td;
2129 
2130  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit",
2131  "prio:%d", child->td_priority);
2132  PROC_LOCK_ASSERT(p, MA_OWNED);
2133  td = FIRST_THREAD_IN_PROC(p);
2134  sched_exit_thread(td, child);
2135 }
2136 
2137 /*
2138  * Penalize another thread for the time spent on this one. This helps to
2139  * worsen the priority and interactivity of processes which schedule batch
2140  * jobs such as make. This has little effect on the make process itself but
2141  * causes new processes spawned by it to receive worse scores immediately.
2142  */
2143 void
2144 sched_exit_thread(struct thread *td, struct thread *child)
2145 {
2146 
2147  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit",
2148  "prio:%d", child->td_priority);
2149  /*
2150  * Give the child's runtime to the parent without returning the
2151  * sleep time as a penalty to the parent. This causes shells that
2152  * launch expensive things to mark their children as expensive.
2153  */
2154  thread_lock(td);
2155  td->td_sched->ts_runtime += child->td_sched->ts_runtime;
2157  sched_priority(td);
2158  thread_unlock(td);
2159 }
2160 
2161 void
2162 sched_preempt(struct thread *td)
2163 {
2164  struct tdq *tdq;
2165 
2166  SDT_PROBE2(sched, , , surrender, td, td->td_proc);
2167 
2168  thread_lock(td);
2169  tdq = TDQ_SELF();
2170  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2171  tdq->tdq_ipipending = 0;
2172  if (td->td_priority > tdq->tdq_lowpri) {
2173  int flags;
2174 
2175  flags = SW_INVOL | SW_PREEMPT;
2176  if (td->td_critnest > 1)
2177  td->td_owepreempt = 1;
2178  else if (TD_IS_IDLETHREAD(td))
2179  mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL);
2180  else
2181  mi_switch(flags | SWT_REMOTEPREEMPT, NULL);
2182  }
2183  thread_unlock(td);
2184 }
2185 
2186 /*
2187  * Fix priorities on return to user-space. Priorities may be elevated due
2188  * to static priorities in msleep() or similar.
2189  */
2190 void
2191 sched_userret(struct thread *td)
2192 {
2193  /*
2194  * XXX we cheat slightly on the locking here to avoid locking in
2195  * the usual case. Setting td_priority here is essentially an
2196  * incomplete workaround for not setting it properly elsewhere.
2197  * Now that some interrupt handlers are threads, not setting it
2198  * properly elsewhere can clobber it in the window between setting
2199  * it here and returning to user mode, so don't waste time setting
2200  * it perfectly here.
2201  */
2202  KASSERT((td->td_flags & TDF_BORROWING) == 0,
2203  ("thread with borrowed priority returning to userland"));
2204  if (td->td_priority != td->td_user_pri) {
2205  thread_lock(td);
2206  td->td_priority = td->td_user_pri;
2207  td->td_base_pri = td->td_user_pri;
2208  tdq_setlowpri(TDQ_SELF(), td);
2209  thread_unlock(td);
2210  }
2211 }
2212 
2213 /*
2214  * Handle a stathz tick. This is really only relevant for timeshare
2215  * threads.
2216  */
2217 void
2218 sched_clock(struct thread *td)
2219 {
2220  struct tdq *tdq;
2221  struct td_sched *ts;
2222 
2223  THREAD_LOCK_ASSERT(td, MA_OWNED);
2224  tdq = TDQ_SELF();
2225 #ifdef SMP
2226  /*
2227  * We run the long term load balancer infrequently on the first cpu.
2228  */
2229  if (balance_tdq == tdq) {
2230  if (balance_ticks && --balance_ticks == 0)
2231  sched_balance();
2232  }
2233 #endif
2234  /*
2235  * Save the old switch count so we have a record of the last ticks
2236  * activity. Initialize the new switch count based on our load.
2237  * If there is some activity seed it to reflect that.
2238  */
2239  tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt;
2240  tdq->tdq_switchcnt = tdq->tdq_load;
2241  /*
2242  * Advance the insert index once for each tick to ensure that all
2243  * threads get a chance to run.
2244  */
2245  if (tdq->tdq_idx == tdq->tdq_ridx) {
2246  tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS;
2247  if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx]))
2248  tdq->tdq_ridx = tdq->tdq_idx;
2249  }
2250  ts = td->td_sched;
2251  sched_pctcpu_update(ts, 1);
2252  if (td->td_pri_class & PRI_FIFO_BIT)
2253  return;
2254  if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) {
2255  /*
2256  * We used a tick; charge it to the thread so
2257  * that we can compute our interactivity.
2258  */
2259  td->td_sched->ts_runtime += tickincr;
2261  sched_priority(td);
2262  }
2263 
2264  /*
2265  * Force a context switch if the current thread has used up a full
2266  * time slice (default is 100ms).
2267  */
2268  if (!TD_IS_IDLETHREAD(td) && ++ts->ts_slice >= tdq_slice(tdq)) {
2269  ts->ts_slice = 0;
2270  td->td_flags |= TDF_NEEDRESCHED | TDF_SLICEEND;
2271  }
2272 }
2273 
2274 /*
2275  * Called once per hz tick.
2276  */
2277 void
2278 sched_tick(int cnt)
2279 {
2280 
2281 }
2282 
2283 /*
2284  * Return whether the current CPU has runnable tasks. Used for in-kernel
2285  * cooperative idle threads.
2286  */
2287 int
2289 {
2290  struct tdq *tdq;
2291  int load;
2292 
2293  load = 1;
2294 
2295  tdq = TDQ_SELF();
2296  if ((curthread->td_flags & TDF_IDLETD) != 0) {
2297  if (tdq->tdq_load > 0)
2298  goto out;
2299  } else
2300  if (tdq->tdq_load - 1 > 0)
2301  goto out;
2302  load = 0;
2303 out:
2304  return (load);
2305 }
2306 
2307 /*
2308  * Choose the highest priority thread to run. The thread is removed from
2309  * the run-queue while running however the load remains. For SMP we set
2310  * the tdq in the global idle bitmask if it idles here.
2311  */
2312 struct thread *
2314 {
2315  struct thread *td;
2316  struct tdq *tdq;
2317 
2318  tdq = TDQ_SELF();
2319  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2320  td = tdq_choose(tdq);
2321  if (td) {
2322  tdq_runq_rem(tdq, td);
2323  tdq->tdq_lowpri = td->td_priority;
2324  return (td);
2325  }
2326  tdq->tdq_lowpri = PRI_MAX_IDLE;
2327  return (PCPU_GET(idlethread));
2328 }
2329 
2330 /*
2331  * Set owepreempt if necessary. Preemption never happens directly in ULE,
2332  * we always request it once we exit a critical section.
2333  */
2334 static inline void
2335 sched_setpreempt(struct thread *td)
2336 {
2337  struct thread *ctd;
2338  int cpri;
2339  int pri;
2340 
2341  THREAD_LOCK_ASSERT(curthread, MA_OWNED);
2342 
2343  ctd = curthread;
2344  pri = td->td_priority;
2345  cpri = ctd->td_priority;
2346  if (pri < cpri)
2347  ctd->td_flags |= TDF_NEEDRESCHED;
2348  if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd))
2349  return;
2350  if (!sched_shouldpreempt(pri, cpri, 0))
2351  return;
2352  ctd->td_owepreempt = 1;
2353 }
2354 
2355 /*
2356  * Add a thread to a thread queue. Select the appropriate runq and add the
2357  * thread to it. This is the internal function called when the tdq is
2358  * predetermined.
2359  */
2360 void
2361 tdq_add(struct tdq *tdq, struct thread *td, int flags)
2362 {
2363 
2364  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2365  KASSERT((td->td_inhibitors == 0),
2366  ("sched_add: trying to run inhibited thread"));
2367  KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
2368  ("sched_add: bad thread state"));
2369  KASSERT(td->td_flags & TDF_INMEM,
2370  ("sched_add: thread swapped out"));
2371 
2372  if (td->td_priority < tdq->tdq_lowpri)
2373  tdq->tdq_lowpri = td->td_priority;
2374  tdq_runq_add(tdq, td, flags);
2375  tdq_load_add(tdq, td);
2376 }
2377 
2378 /*
2379  * Select the target thread queue and add a thread to it. Request
2380  * preemption or IPI a remote processor if required.
2381  */
2382 void
2383 sched_add(struct thread *td, int flags)
2384 {
2385  struct tdq *tdq;
2386 #ifdef SMP
2387  int cpu;
2388 #endif
2389 
2390  KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
2391  "prio:%d", td->td_priority, KTR_ATTR_LINKED,
2392  sched_tdname(curthread));
2393  KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
2394  KTR_ATTR_LINKED, sched_tdname(td));
2395  SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL,
2396  flags & SRQ_PREEMPTED);
2397  THREAD_LOCK_ASSERT(td, MA_OWNED);
2398  /*
2399  * Recalculate the priority before we select the target cpu or
2400  * run-queue.
2401  */
2402  if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
2403  sched_priority(td);
2404 #ifdef SMP
2405  /*
2406  * Pick the destination cpu and if it isn't ours transfer to the
2407  * target cpu.
2408  */
2409  cpu = sched_pickcpu(td, flags);
2410  tdq = sched_setcpu(td, cpu, flags);
2411  tdq_add(tdq, td, flags);
2412  if (cpu != PCPU_GET(cpuid)) {
2413  tdq_notify(tdq, td);
2414  return;
2415  }
2416 #else
2417  tdq = TDQ_SELF();
2418  TDQ_LOCK(tdq);
2419  /*
2420  * Now that the thread is moving to the run-queue, set the lock
2421  * to the scheduler's lock.
2422  */
2423  thread_lock_set(td, TDQ_LOCKPTR(tdq));
2424  tdq_add(tdq, td, flags);
2425 #endif
2426  if (!(flags & SRQ_YIELDING))
2427  sched_setpreempt(td);
2428 }
2429 
2430 /*
2431  * Remove a thread from a run-queue without running it. This is used
2432  * when we're stealing a thread from a remote queue. Otherwise all threads
2433  * exit by calling sched_exit_thread() and sched_throw() themselves.
2434  */
2435 void
2436 sched_rem(struct thread *td)
2437 {
2438  struct tdq *tdq;
2439 
2440  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem",
2441  "prio:%d", td->td_priority);
2442  SDT_PROBE3(sched, , , dequeue, td, td->td_proc, NULL);
2443  tdq = TDQ_CPU(td->td_sched->ts_cpu);
2444  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2445  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2446  KASSERT(TD_ON_RUNQ(td),
2447  ("sched_rem: thread not on run queue"));
2448  tdq_runq_rem(tdq, td);
2449  tdq_load_rem(tdq, td);
2450  TD_SET_CAN_RUN(td);
2451  if (td->td_priority == tdq->tdq_lowpri)
2452  tdq_setlowpri(tdq, NULL);
2453 }
2454 
2455 /*
2456  * Fetch cpu utilization information. Updates on demand.
2457  */
2458 fixpt_t
2459 sched_pctcpu(struct thread *td)
2460 {
2461  fixpt_t pctcpu;
2462  struct td_sched *ts;
2463 
2464  pctcpu = 0;
2465  ts = td->td_sched;
2466  if (ts == NULL)
2467  return (0);
2468 
2469  THREAD_LOCK_ASSERT(td, MA_OWNED);
2470  sched_pctcpu_update(ts, TD_IS_RUNNING(td));
2471  if (ts->ts_ticks) {
2472  int rtick;
2473 
2474  /* How many rtick per second ? */
2475  rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz);
2476  pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT;
2477  }
2478 
2479  return (pctcpu);
2480 }
2481 
2482 /*
2483  * Enforce affinity settings for a thread. Called after adjustments to
2484  * cpumask.
2485  */
2486 void
2487 sched_affinity(struct thread *td)
2488 {
2489 #ifdef SMP
2490  struct td_sched *ts;
2491 
2492  THREAD_LOCK_ASSERT(td, MA_OWNED);
2493  ts = td->td_sched;
2494  if (THREAD_CAN_SCHED(td, ts->ts_cpu))
2495  return;
2496  if (TD_ON_RUNQ(td)) {
2497  sched_rem(td);
2498  sched_add(td, SRQ_BORING);
2499  return;
2500  }
2501  if (!TD_IS_RUNNING(td))
2502  return;
2503  /*
2504  * Force a switch before returning to userspace. If the
2505  * target thread is not running locally send an ipi to force
2506  * the issue.
2507  */
2508  td->td_flags |= TDF_NEEDRESCHED;
2509  if (td != curthread)
2510  ipi_cpu(ts->ts_cpu, IPI_PREEMPT);
2511 #endif
2512 }
2513 
2514 /*
2515  * Bind a thread to a target cpu.
2516  */
2517 void
2518 sched_bind(struct thread *td, int cpu)
2519 {
2520  struct td_sched *ts;
2521 
2522  THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED);
2523  KASSERT(td == curthread, ("sched_bind: can only bind curthread"));
2524  ts = td->td_sched;
2525  if (ts->ts_flags & TSF_BOUND)
2526  sched_unbind(td);
2527  KASSERT(THREAD_CAN_MIGRATE(td), ("%p must be migratable", td));
2528  ts->ts_flags |= TSF_BOUND;
2529  sched_pin();
2530  if (PCPU_GET(cpuid) == cpu)
2531  return;
2532  ts->ts_cpu = cpu;
2533  /* When we return from mi_switch we'll be on the correct cpu. */
2534  mi_switch(SW_VOL, NULL);
2535 }
2536 
2537 /*
2538  * Release a bound thread.
2539  */
2540 void
2541 sched_unbind(struct thread *td)
2542 {
2543  struct td_sched *ts;
2544 
2545  THREAD_LOCK_ASSERT(td, MA_OWNED);
2546  KASSERT(td == curthread, ("sched_unbind: can only bind curthread"));
2547  ts = td->td_sched;
2548  if ((ts->ts_flags & TSF_BOUND) == 0)
2549  return;
2550  ts->ts_flags &= ~TSF_BOUND;
2551  sched_unpin();
2552 }
2553 
2554 int
2555 sched_is_bound(struct thread *td)
2556 {
2557  THREAD_LOCK_ASSERT(td, MA_OWNED);
2558  return (td->td_sched->ts_flags & TSF_BOUND);
2559 }
2560 
2561 /*
2562  * Basic yield call.
2563  */
2564 void
2565 sched_relinquish(struct thread *td)
2566 {
2567  thread_lock(td);
2568  mi_switch(SW_VOL | SWT_RELINQUISH, NULL);
2569  thread_unlock(td);
2570 }
2571 
2572 /*
2573  * Return the total system load.
2574  */
2575 int
2577 {
2578 #ifdef SMP
2579  int total;
2580  int i;
2581 
2582  total = 0;
2583  CPU_FOREACH(i)
2584  total += TDQ_CPU(i)->tdq_sysload;
2585  return (total);
2586 #else
2587  return (TDQ_SELF()->tdq_sysload);
2588 #endif
2589 }
2590 
2591 int
2593 {
2594  return (sizeof(struct proc));
2595 }
2596 
2597 int
2599 {
2600  return (sizeof(struct thread) + sizeof(struct td_sched));
2601 }
2602 
2603 #ifdef SMP
2604 #define TDQ_IDLESPIN(tdq) \
2605  ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0)
2606 #else
2607 #define TDQ_IDLESPIN(tdq) 1
2608 #endif
2609 
2610 /*
2611  * The actual idle process.
2612  */
2613 void
2615 {
2616  struct thread *td;
2617  struct tdq *tdq;
2618  int oldswitchcnt, switchcnt;
2619  int i;
2620 
2621  mtx_assert(&Giant, MA_NOTOWNED);
2622  td = curthread;
2623  tdq = TDQ_SELF();
2624  THREAD_NO_SLEEPING();
2625  oldswitchcnt = -1;
2626  for (;;) {
2627  if (tdq->tdq_load) {
2628  thread_lock(td);
2629  mi_switch(SW_VOL | SWT_IDLE, NULL);
2630  thread_unlock(td);
2631  }
2632  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2633 #ifdef SMP
2634  if (switchcnt != oldswitchcnt) {
2635  oldswitchcnt = switchcnt;
2636  if (tdq_idled(tdq) == 0)
2637  continue;
2638  }
2639  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2640 #else
2641  oldswitchcnt = switchcnt;
2642 #endif
2643  /*
2644  * If we're switching very frequently, spin while checking
2645  * for load rather than entering a low power state that
2646  * may require an IPI. However, don't do any busy
2647  * loops while on SMT machines as this simply steals
2648  * cycles from cores doing useful work.
2649  */
2650  if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) {
2651  for (i = 0; i < sched_idlespins; i++) {
2652  if (tdq->tdq_load)
2653  break;
2654  cpu_spinwait();
2655  }
2656  }
2657 
2658  /* If there was context switch during spin, restart it. */
2659  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2660  if (tdq->tdq_load != 0 || switchcnt != oldswitchcnt)
2661  continue;
2662 
2663  /* Run main MD idle handler. */
2664  tdq->tdq_cpu_idle = 1;
2665  /*
2666  * Make sure that tdq_cpu_idle update is globally visible
2667  * before cpu_idle() read tdq_load. The order is important
2668  * to avoid race with tdq_notify.
2669  */
2670  atomic_thread_fence_seq_cst();
2671  cpu_idle(switchcnt * 4 > sched_idlespinthresh);
2672  tdq->tdq_cpu_idle = 0;
2673 
2674  /*
2675  * Account thread-less hardware interrupts and
2676  * other wakeup reasons equal to context switches.
2677  */
2678  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2679  if (switchcnt != oldswitchcnt)
2680  continue;
2681  tdq->tdq_switchcnt++;
2682  oldswitchcnt++;
2683  }
2684 }
2685 
2686 /*
2687  * A CPU is entering for the first time or a thread is exiting.
2688  */
2689 void
2690 sched_throw(struct thread *td)
2691 {
2692  struct thread *newtd;
2693  struct tdq *tdq;
2694 
2695  tdq = TDQ_SELF();
2696  if (td == NULL) {
2697  /* Correct spinlock nesting and acquire the correct lock. */
2698  TDQ_LOCK(tdq);
2699  spinlock_exit();
2700  PCPU_SET(switchtime, cpu_ticks());
2701  PCPU_SET(switchticks, ticks);
2702  } else {
2703  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2704  tdq_load_rem(tdq, td);
2705  lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
2706  }
2707  KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
2708  newtd = choosethread();
2709  TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
2710  cpu_throw(td, newtd); /* doesn't return */
2711 }
2712 
2713 /*
2714  * This is called from fork_exit(). Just acquire the correct locks and
2715  * let fork do the rest of the work.
2716  */
2717 void
2718 sched_fork_exit(struct thread *td)
2719 {
2720  struct tdq *tdq;
2721  int cpuid;
2722 
2723  /*
2724  * Finish setting up thread glue so that it begins execution in a
2725  * non-nested critical section with the scheduler lock held.
2726  */
2727  cpuid = PCPU_GET(cpuid);
2728  tdq = TDQ_CPU(cpuid);
2729  if (TD_IS_IDLETHREAD(td))
2730  td->td_lock = TDQ_LOCKPTR(tdq);
2731  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2732  td->td_oncpu = cpuid;
2733  TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
2734  lock_profile_obtain_lock_success(
2735  &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
2736 }
2737 
2738 /*
2739  * Create on first use to catch odd startup conditons.
2740  */
2741 char *
2742 sched_tdname(struct thread *td)
2743 {
2744 #ifdef KTR
2745  struct td_sched *ts;
2746 
2747  ts = td->td_sched;
2748  if (ts->ts_name[0] == '\0')
2749  snprintf(ts->ts_name, sizeof(ts->ts_name),
2750  "%s tid %d", td->td_name, td->td_tid);
2751  return (ts->ts_name);
2752 #else
2753  return (td->td_name);
2754 #endif
2755 }
2756 
2757 #ifdef KTR
2758 void
2759 sched_clear_tdname(struct thread *td)
2760 {
2761  struct td_sched *ts;
2762 
2763  ts = td->td_sched;
2764  ts->ts_name[0] = '\0';
2765 }
2766 #endif
2767 
2768 #ifdef SMP
2769 
2770 /*
2771  * Build the CPU topology dump string. Is recursively called to collect
2772  * the topology tree.
2773  */
2774 static int
2775 sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg,
2776  int indent)
2777 {
2778  char cpusetbuf[CPUSETBUFSIZ];
2779  int i, first;
2780 
2781  sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent,
2782  "", 1 + indent / 2, cg->cg_level);
2783  sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"%s\">", indent, "",
2784  cg->cg_count, cpusetobj_strprint(cpusetbuf, &cg->cg_mask));
2785  first = TRUE;
2786  for (i = 0; i < MAXCPU; i++) {
2787  if (CPU_ISSET(i, &cg->cg_mask)) {
2788  if (!first)
2789  sbuf_printf(sb, ", ");
2790  else
2791  first = FALSE;
2792  sbuf_printf(sb, "%d", i);
2793  }
2794  }
2795  sbuf_printf(sb, "</cpu>\n");
2796 
2797  if (cg->cg_flags != 0) {
2798  sbuf_printf(sb, "%*s <flags>", indent, "");
2799  if ((cg->cg_flags & CG_FLAG_HTT) != 0)
2800  sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>");
2801  if ((cg->cg_flags & CG_FLAG_THREAD) != 0)
2802  sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>");
2803  if ((cg->cg_flags & CG_FLAG_SMT) != 0)
2804  sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>");
2805  sbuf_printf(sb, "</flags>\n");
2806  }
2807 
2808  if (cg->cg_children > 0) {
2809  sbuf_printf(sb, "%*s <children>\n", indent, "");
2810  for (i = 0; i < cg->cg_children; i++)
2811  sysctl_kern_sched_topology_spec_internal(sb,
2812  &cg->cg_child[i], indent+2);
2813  sbuf_printf(sb, "%*s </children>\n", indent, "");
2814  }
2815  sbuf_printf(sb, "%*s</group>\n", indent, "");
2816  return (0);
2817 }
2818 
2819 /*
2820  * Sysctl handler for retrieving topology dump. It's a wrapper for
2821  * the recursive sysctl_kern_smp_topology_spec_internal().
2822  */
2823 static int
2824 sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS)
2825 {
2826  struct sbuf *topo;
2827  int err;
2828 
2829  KASSERT(cpu_top != NULL, ("cpu_top isn't initialized"));
2830 
2831  topo = sbuf_new_for_sysctl(NULL, NULL, 512, req);
2832  if (topo == NULL)
2833  return (ENOMEM);
2834 
2835  sbuf_printf(topo, "<groups>\n");
2836  err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1);
2837  sbuf_printf(topo, "</groups>\n");
2838 
2839  if (err == 0) {
2840  err = sbuf_finish(topo);
2841  }
2842  sbuf_delete(topo);
2843  return (err);
2844 }
2845 
2846 #endif
2847 
2848 static int
2849 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
2850 {
2851  int error, new_val, period;
2852 
2853  period = 1000000 / realstathz;
2854  new_val = period * sched_slice;
2855  error = sysctl_handle_int(oidp, &new_val, 0, req);
2856  if (error != 0 || req->newptr == NULL)
2857  return (error);
2858  if (new_val <= 0)
2859  return (EINVAL);
2860  sched_slice = imax(1, (new_val + period / 2) / period);
2861  sched_slice_min = sched_slice / SCHED_SLICE_MIN_DIVISOR;
2862  hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
2863  realstathz);
2864  return (0);
2865 }
2866 
2867 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler");
2868 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0,
2869  "Scheduler name");
2870 SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW,
2871  NULL, 0, sysctl_kern_quantum, "I",
2872  "Quantum for timeshare threads in microseconds");
2873 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
2874  "Quantum for timeshare threads in stathz ticks");
2875 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0,
2876  "Interactivity score threshold");
2877 SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW,
2878  &preempt_thresh, 0,
2879  "Maximal (lowest) priority for preemption");
2880 SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 0,
2881  "Assign static kernel priorities to sleeping threads");
2882 SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 0,
2883  "Number of times idle thread will spin waiting for new work");
2884 SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW,
2886  "Threshold before we will permit idle thread spinning");
2887 #ifdef SMP
2888 SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0,
2889  "Number of hz ticks to keep thread affinity for");
2890 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0,
2891  "Enables the long-term load balancer");
2892 SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW,
2893  &balance_interval, 0,
2894  "Average period in stathz ticks to run the long-term balancer");
2895 SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0,
2896  "Attempts to steal work from other cores before idling");
2897 SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0,
2898  "Minimum load on remote CPU before we'll steal");
2899 SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING |
2900  CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A",
2901  "XML dump of detected CPU topology");
2902 #endif
2903 
2904 /* ps compat. All cpu percentages from ULE are weighted. */
2905 static int ccpu = 0;
2906 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
static struct tdq tdq_cpu
Definition: sched_ule.c:286
volatile int smp_started
Definition: subr_smp.c:72
u_int ts_runtime
Definition: sched_ule.c:97
static void sched_initticks(void *dummy)
Definition: sched_ule.c:1412
int ts_ticks
Definition: sched_ule.c:100
#define TS_NAME_LEN
Definition: sched_ule.c:82
#define TDQ_LOCK_ASSERT(t, type)
Definition: sched_ule.c:293
static int sched_shouldpreempt(int, int, int)
Definition: sched_ule.c:416
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Definition: sched_ule.c:1628
SDT_PROBE_DEFINE2(sched,,, load__change,"int","int")
#define SCHED_TICK_SHIFT
Definition: sched_ule.c:144
#define TDQ_CPU(x)
Definition: sched_ule.c:290
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Definition: kern_switch.c:338
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Definition: sched_ule.c:1609
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Definition: sched_ule.c:231
volatile int tdq_cpu_idle
Definition: sched_ule.c:237
void turnstile_adjust(struct thread *td, u_char oldpri)
void sched_lend_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1720
struct thread * sched_choose(void)
Definition: sched_ule.c:2313
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Definition: sched_ule.c:2113
int snprintf(char *str, size_t size, const char *format,...)
Definition: subr_prf.c:514
__FBSDID("$FreeBSD: head/sys/kern/sched_ule.c 285353 2015-07-10 08:54:12Z kib $")
struct timespec * ts
Definition: clock_if.m:39
#define TDF_SLICEEND
Definition: sched_ule.c:195
short ts_flags
Definition: sched_ule.c:92
void sched_exit_thread(struct thread *td, struct thread *child)
Definition: sched_ule.c:2144
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Definition: sched_ule.c:2070
int bootverbose
Definition: init_main.c:116
void *** start
Definition: linker_if.m:86
u_int mp_maxid
Definition: subr_smp.c:73
u_int ts_slptime
Definition: sched_ule.c:96
#define SCHED_PRI_MIN
Definition: sched_ule.c:162
#define SCHED_PRI_RANGE
Definition: sched_ule.c:164
static void sched_setup(void *dummy)
Definition: sched_ule.c:1388
#define THREAD_CAN_SCHED(td, cpu)
Definition: sched_ule.c:112
static int sched_interact_score(struct thread *)
Definition: sched_ule.c:1455
static __inline void tdq_runq_rem(struct tdq *, struct thread *)
Definition: sched_ule.c:505
void sched_user_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1786
const char * panicstr
SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD,"ULE", 0,"Scheduler name")
static int sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
Definition: sched_ule.c:2849
struct proc proc0
Definition: init_main.c:101
short tdq_oldswitchcnt
Definition: sched_ule.c:241
void panic(const char *fmt,...)
static void sched_interact_update(struct thread *)
Definition: sched_ule.c:1547
struct thread * choosethread(void)
Definition: kern_switch.c:154
struct mtx_padalign tdq_lock
Definition: sched_ule.c:234
u_char tdq_ipipending
Definition: sched_ule.c:243
struct tdq __aligned(64)
#define PRI_MIN_BATCH
Definition: sched_ule.c:128
void runq_remove_idx(struct runq *rq, struct thread *td, u_char *idx)
Definition: kern_switch.c:494
char * sched_tdname(struct thread *td)
Definition: sched_ule.c:2742
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Definition: subr_pcpu.c:278
static int ccpu
Definition: sched_ule.c:2905
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Definition: sched_4bsd.c:97
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Definition: sched_ule.c:99
static void tdq_setup(struct tdq *)
Definition: sched_ule.c:1345
const char * name
Definition: kern_fail.c:97
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Definition: sched_4bsd.c:95
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Definition: kern_synch.c:413
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Definition: sched_ule.c:1999
#define TSF_XFERABLE
Definition: sched_ule.c:107
int ts_rltick
Definition: sched_ule.c:94
SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL)
static void tdq_load_rem(struct tdq *, struct thread *)
Definition: sched_ule.c:549
SDT_PROBE_DEFINE(sched,,, on__cpu)
u_char tdq_ridx
Definition: sched_ule.c:245
int ts_ltick
Definition: sched_ule.c:98
volatile int tdq_load
Definition: sched_ule.c:229
struct thread * runq_choose_from(struct runq *rq, u_char idx)
Definition: kern_switch.c:462
static int sched_idlespins
Definition: sched_ule.c:220
#define PRI_MAX_INTERACT
Definition: sched_ule.c:127
int ts_slice
Definition: sched_4bsd.c:96
char tdq_name[TDQ_NAME_LEN]
Definition: sched_ule.c:249
#define SCHED_INTERACT_HALF
Definition: sched_ule.c:185
#define TDQ_IDLESPIN(tdq)
Definition: sched_ule.c:2607
static int sched_idlespinthresh
Definition: sched_ule.c:221
#define TDQ_ID(x)
Definition: sched_ule.c:288
static struct runq runq
Definition: sched_4bsd.c:156
void runq_add_pri(struct runq *rq, struct thread *td, u_char pri, int flags)
Definition: kern_switch.c:357
void runq_init(struct runq *rq)
Definition: kern_switch.c:235
#define SCHED_SLICE_MIN_DIVISOR
Definition: sched_ule.c:192
static int sched_slice_min
Definition: sched_ule.c:209
static void tdq_setlowpri(struct tdq *tdq, struct thread *ctd)
Definition: sched_ule.c:593
void sched_throw(struct thread *td)
Definition: sched_ule.c:2690
struct thread * runq_choose(struct runq *rq)
Definition: kern_switch.c:442
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Definition: kern_mutex.c:742
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Definition: sched_ule.c:2718
struct cpuset * cpuset_ref(struct cpuset *set)
Definition: kern_cpuset.c:126
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Definition: sched_ule.c:2565
static int dummy
void tdq_print(int cpu)
Definition: sched_ule.c:391
Definition: sched_ule.c:228
struct mtx Giant
Definition: kern_mutex.c:145
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Definition: sched_ule.c:2020
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Definition: sched_4bsd.c:98
static struct td_sched td_sched0
Definition: sched_ule.c:109
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Definition: sched_ule.c:2598
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Definition: sched_ule.c:2436
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#define SCHED_TICK_SECS
Definition: sched_ule.c:141
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Definition: sched_ule.c:235
int ts_cpu
Definition: sched_ule.c:93
SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW,&sched_slice, 0,"Quantum for timeshare threads in stathz ticks")
int sbuf_printf(struct sbuf *s, const char *fmt,...)
Definition: subr_sbuf.c:663
#define SCHED_SLP_RUN_FORK
Definition: sched_ule.c:183
void sched_lend_user_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1796
DPCPU_DEFINE(sbintime_t, hardclocktime)
#define PRI_MIN_INTERACT
Definition: sched_ule.c:126
static struct thread * tdq_choose(struct tdq *)
Definition: sched_ule.c:1315
static int tickincr
Definition: sched_ule.c:206
int sched_is_bound(struct thread *td)
Definition: sched_ule.c:2555
int mask
Definition: subr_acl_nfs4.c:69
static struct mtx * sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags)
Definition: sched_ule.c:1813
int sysctl_handle_int(SYSCTL_HANDLER_ARGS)
Definition: kern_sysctl.c:1146
void sched_tick(int cnt)
Definition: sched_ule.c:2278
#define TDQ_SELF()
Definition: sched_ule.c:289
#define TDQ_LOADNAME_LEN
Definition: sched_ule.c:84
#define SCHED_TICK_MAX
Definition: sched_ule.c:143
struct runq tdq_timeshare
Definition: sched_ule.c:247
void sched_clock(struct thread *td)
Definition: sched_ule.c:2218
static void runq_print(struct runq *rq)
Definition: sched_ule.c:363
static void sched_thread_priority(struct thread *, u_char)
Definition: sched_ule.c:1665
void runq_remove(struct runq *rq, struct thread *td)
Definition: kern_switch.c:487
struct runq tdq_realtime
Definition: sched_ule.c:246
static __inline void tdq_runq_add(struct tdq *, struct thread *, int)
Definition: sched_ule.c:454
#define SCHED_PRI_NICE(nice)
Definition: sched_ule.c:168
void sched_affinity(struct thread *td)
Definition: sched_ule.c:2487
int printf(const char *fmt,...)
Definition: subr_prf.c:378
void sched_exit(struct proc *p, struct thread *child)
Definition: sched_ule.c:2126
struct runq tdq_idle
Definition: sched_ule.c:248
#define SCHED_PRI_TICKS(ts)
Definition: sched_ule.c:165
void sbuf_delete(struct sbuf *s)
Definition: subr_sbuf.c:790
#define TDQ_LOCK_FLAGS(t, f)
Definition: sched_ule.c:295
SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW, NULL, 0, sysctl_kern_quantum,"I","Quantum for timeshare threads in microseconds")
void sched_idletd(void *dummy)
Definition: sched_ule.c:2614
void sched_unlend_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1736
int tdq_sysload
Definition: sched_ule.c:238
#define TSF_BOUND
Definition: sched_ule.c:106
#define SCHED_TICK_HZ(ts)
Definition: sched_ule.c:145
static void thread_unblock_switch(struct thread *td, struct mtx *mtx)
Definition: sched_ule.c:1850
int sbuf_finish(struct sbuf *s)
Definition: subr_sbuf.c:725
void sched_preempt(struct thread *td)
Definition: sched_ule.c:2162
static int realstathz
Definition: sched_ule.c:207
volatile int tdq_load
Definition: sched_ule.c:236
#define TDQ_LOCK(t)
Definition: sched_ule.c:294
#define SCHED_SLICE_DEFAULT_DIVISOR
Definition: sched_ule.c:191
SDT_PROBE_DEFINE4(sched,,, enqueue,"struct thread *","struct proc *","void *","int")
SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0,"Scheduler")
#define TDQ_UNLOCK(t)
Definition: sched_ule.c:296
volatile int ticks
Definition: kern_clock.c:380
int sched_load(void)
Definition: sched_ule.c:2576
int hogticks
Definition: kern_synch.c:80
SDT_PROVIDER_DEFINE(sched)
static int sched_interact
Definition: sched_ule.c:205
static int tdq_slice(struct tdq *tdq)
Definition: sched_ule.c:571
static void sched_interact_fork(struct thread *)
Definition: sched_ule.c:1592
int stathz
Definition: kern_clock.c:377
static void sched_priority(struct thread *)
Definition: sched_ule.c:1495
void sched_nice(struct proc *p, int nice)
Definition: sched_ule.c:1980
#define SCHED_SLP_RUN_MAX
Definition: sched_ule.c:182
static void sched_setpreempt(struct thread *td)
Definition: sched_ule.c:2335
int tdq_transferable
Definition: sched_ule.c:239
static int sched_slice
Definition: sched_ule.c:208
char * cpusetobj_strprint(char *buf, const cpuset_t *set)
Definition: kern_cpuset.c:634
void sched_userret(struct thread *td)
Definition: sched_ule.c:2191
#define TDQ_LOCKPTR(t)
Definition: sched_ule.c:297
void sched_fork(struct thread *td, struct thread *child)
Definition: sched_ule.c:2051
#define SCHED_INTERACT_THRESH
Definition: sched_ule.c:186
#define PRI_MAX_BATCH
Definition: sched_ule.c:129
static void tdq_add(struct tdq *, struct thread *, int)
Definition: sched_ule.c:2361
struct mtx * thread_lock_block(struct thread *td)
Definition: kern_mutex.c:721
u_char tdq_idx
Definition: sched_ule.c:244
#define SCHED_TICK_TARG
Definition: sched_ule.c:142
int sched_runnable(void)
Definition: sched_ule.c:2288
void sched_unbind(struct thread *td)
Definition: sched_ule.c:2541
static int preempt_thresh
Definition: sched_ule.c:217
#define PRI_BATCH_RANGE
Definition: sched_ule.c:124
#define THREAD_CAN_MIGRATE(td)
Definition: sched_ule.c:111
void sched_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1756
SDT_PROBE_DEFINE3(sched,,, change__pri,"struct thread *","struct proc *","uint8_t")
void sched_add(struct thread *td, int flags)
Definition: sched_ule.c:2383
short tdq_switchcnt
Definition: sched_ule.c:240
u_char tdq_lowpri
Definition: sched_ule.c:235
u_char tdq_lowpri
Definition: sched_ule.c:242
static void tdq_load_add(struct tdq *, struct thread *)
Definition: sched_ule.c:531
cpu_tick_f * cpu_ticks
Definition: kern_tc.c:2038
void thread_lock_unblock(struct thread *td, struct mtx *new)
Definition: kern_mutex.c:734
#define TDQ_NAME_LEN
Definition: sched_ule.c:83
static int static_boost
Definition: sched_ule.c:219
void sched_bind(struct thread *td, int cpu)
Definition: sched_ule.c:2518
struct sbuf * sbuf_new_for_sysctl(struct sbuf *s, char *buf, int length, struct sysctl_req *req)
Definition: kern_sysctl.c:1840
int hz
Definition: subr_param.c:84
fixpt_t sched_pctcpu(struct thread *td)
Definition: sched_ule.c:2459
int sched_sizeof_proc(void)
Definition: sched_ule.c:2592
static void sched_pctcpu_update(struct td_sched *, int)
Definition: sched_ule.c:1642