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 301456 2016-06-05 17:04:03Z 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 #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0)
110 #define THREAD_CAN_SCHED(td, cpu) \
111  CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask)
112 
113 _Static_assert(sizeof(struct thread) + sizeof(struct td_sched) <=
114  sizeof(struct thread0_storage),
115  "increase struct thread0_storage.t0st_sched size");
116 
117 /*
118  * Priority ranges used for interactive and non-interactive timeshare
119  * threads. The timeshare priorities are split up into four ranges.
120  * The first range handles interactive threads. The last three ranges
121  * (NHALF, x, and NHALF) handle non-interactive threads with the outer
122  * ranges supporting nice values.
123  */
124 #define PRI_TIMESHARE_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1)
125 #define PRI_INTERACT_RANGE ((PRI_TIMESHARE_RANGE - SCHED_PRI_NRESV) / 2)
126 #define PRI_BATCH_RANGE (PRI_TIMESHARE_RANGE - PRI_INTERACT_RANGE)
127 
128 #define PRI_MIN_INTERACT PRI_MIN_TIMESHARE
129 #define PRI_MAX_INTERACT (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE - 1)
130 #define PRI_MIN_BATCH (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE)
131 #define PRI_MAX_BATCH PRI_MAX_TIMESHARE
132 
133 /*
134  * Cpu percentage computation macros and defines.
135  *
136  * SCHED_TICK_SECS: Number of seconds to average the cpu usage across.
137  * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across.
138  * SCHED_TICK_MAX: Maximum number of ticks before scaling back.
139  * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results.
140  * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count.
141  * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks.
142  */
143 #define SCHED_TICK_SECS 10
144 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS)
145 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz)
146 #define SCHED_TICK_SHIFT 10
147 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT)
148 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz))
149 
150 /*
151  * These macros determine priorities for non-interactive threads. They are
152  * assigned a priority based on their recent cpu utilization as expressed
153  * by the ratio of ticks to the tick total. NHALF priorities at the start
154  * and end of the MIN to MAX timeshare range are only reachable with negative
155  * or positive nice respectively.
156  *
157  * PRI_RANGE: Priority range for utilization dependent priorities.
158  * PRI_NRESV: Number of nice values.
159  * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total.
160  * PRI_NICE: Determines the part of the priority inherited from nice.
161  */
162 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN)
163 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2)
164 #define SCHED_PRI_MIN (PRI_MIN_BATCH + SCHED_PRI_NHALF)
165 #define SCHED_PRI_MAX (PRI_MAX_BATCH - SCHED_PRI_NHALF)
166 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN + 1)
167 #define SCHED_PRI_TICKS(ts) \
168  (SCHED_TICK_HZ((ts)) / \
169  (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE))
170 #define SCHED_PRI_NICE(nice) (nice)
171 
172 /*
173  * These determine the interactivity of a process. Interactivity differs from
174  * cpu utilization in that it expresses the voluntary time slept vs time ran
175  * while cpu utilization includes all time not running. This more accurately
176  * models the intent of the thread.
177  *
178  * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate
179  * before throttling back.
180  * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time.
181  * INTERACT_MAX: Maximum interactivity value. Smaller is better.
182  * INTERACT_THRESH: Threshold for placement on the current runq.
183  */
184 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT)
185 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT)
186 #define SCHED_INTERACT_MAX (100)
187 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2)
188 #define SCHED_INTERACT_THRESH (30)
189 
190 /*
191  * These parameters determine the slice behavior for batch work.
192  */
193 #define SCHED_SLICE_DEFAULT_DIVISOR 10 /* ~94 ms, 12 stathz ticks. */
194 #define SCHED_SLICE_MIN_DIVISOR 6 /* DEFAULT/MIN = ~16 ms. */
195 
196 /* Flags kept in td_flags. */
197 #define TDF_SLICEEND TDF_SCHED2 /* Thread time slice is over. */
198 
199 /*
200  * tickincr: Converts a stathz tick into a hz domain scaled by
201  * the shift factor. Without the shift the error rate
202  * due to rounding would be unacceptably high.
203  * realstathz: stathz is sometimes 0 and run off of hz.
204  * sched_slice: Runtime of each thread before rescheduling.
205  * preempt_thresh: Priority threshold for preemption and remote IPIs.
206  */
208 static int tickincr = 8 << SCHED_TICK_SHIFT;
209 static int realstathz = 127; /* reset during boot. */
210 static int sched_slice = 10; /* reset during boot. */
211 static int sched_slice_min = 1; /* reset during boot. */
212 #ifdef PREEMPTION
213 #ifdef FULL_PREEMPTION
214 static int preempt_thresh = PRI_MAX_IDLE;
215 #else
216 static int preempt_thresh = PRI_MIN_KERN;
217 #endif
218 #else
219 static int preempt_thresh = 0;
220 #endif
222 static int sched_idlespins = 10000;
223 static int sched_idlespinthresh = -1;
224 
225 /*
226  * tdq - per processor runqs and statistics. All fields are protected by the
227  * tdq_lock. The load and lowpri may be accessed without to avoid excess
228  * locking in sched_pickcpu();
229  */
230 struct tdq {
231  /*
232  * Ordered to improve efficiency of cpu_search() and switch().
233  * tdq_lock is padded to avoid false sharing with tdq_load and
234  * tdq_cpu_idle.
235  */
236  struct mtx_padalign tdq_lock; /* run queue lock. */
237  struct cpu_group *tdq_cg; /* Pointer to cpu topology. */
238  volatile int tdq_load; /* Aggregate load. */
239  volatile int tdq_cpu_idle; /* cpu_idle() is active. */
240  int tdq_sysload; /* For loadavg, !ITHD load. */
241  int tdq_transferable; /* Transferable thread count. */
242  short tdq_switchcnt; /* Switches this tick. */
243  short tdq_oldswitchcnt; /* Switches last tick. */
244  u_char tdq_lowpri; /* Lowest priority thread. */
245  u_char tdq_ipipending; /* IPI pending. */
246  u_char tdq_idx; /* Current insert index. */
247  u_char tdq_ridx; /* Current removal index. */
248  struct runq tdq_realtime; /* real-time run queue. */
249  struct runq tdq_timeshare; /* timeshare run queue. */
250  struct runq tdq_idle; /* Queue of IDLE threads. */
252 #ifdef KTR
253  char tdq_loadname[TDQ_LOADNAME_LEN];
254 #endif
255 } __aligned(64);
256 
257 /* Idle thread states and config. */
258 #define TDQ_RUNNING 1
259 #define TDQ_IDLE 2
260 
261 #ifdef SMP
262 struct cpu_group *cpu_top; /* CPU topology */
263 
264 #define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000))
265 #define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity))
266 
267 /*
268  * Run-time tunables.
269  */
270 static int rebalance = 1;
271 static int balance_interval = 128; /* Default set in sched_initticks(). */
272 static int affinity;
273 static int steal_idle = 1;
274 static int steal_thresh = 2;
275 
276 /*
277  * One thread queue per processor.
278  */
279 static struct tdq tdq_cpu[MAXCPU];
280 static struct tdq *balance_tdq;
281 static int balance_ticks;
282 static DPCPU_DEFINE(uint32_t, randomval);
283 
284 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)])
285 #define TDQ_CPU(x) (&tdq_cpu[(x)])
286 #define TDQ_ID(x) ((int)((x) - tdq_cpu))
287 #else /* !SMP */
288 static struct tdq tdq_cpu;
289 
290 #define TDQ_ID(x) (0)
291 #define TDQ_SELF() (&tdq_cpu)
292 #define TDQ_CPU(x) (&tdq_cpu)
293 #endif
294 
295 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type))
296 #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t)))
297 #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f))
298 #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t)))
299 #define TDQ_LOCKPTR(t) ((struct mtx *)(&(t)->tdq_lock))
300 
301 static void sched_priority(struct thread *);
302 static void sched_thread_priority(struct thread *, u_char);
303 static int sched_interact_score(struct thread *);
304 static void sched_interact_update(struct thread *);
305 static void sched_interact_fork(struct thread *);
306 static void sched_pctcpu_update(struct td_sched *, int);
307 
308 /* Operations on per processor queues */
309 static struct thread *tdq_choose(struct tdq *);
310 static void tdq_setup(struct tdq *);
311 static void tdq_load_add(struct tdq *, struct thread *);
312 static void tdq_load_rem(struct tdq *, struct thread *);
313 static __inline void tdq_runq_add(struct tdq *, struct thread *, int);
314 static __inline void tdq_runq_rem(struct tdq *, struct thread *);
315 static inline int sched_shouldpreempt(int, int, int);
316 void tdq_print(int cpu);
317 static void runq_print(struct runq *rq);
318 static void tdq_add(struct tdq *, struct thread *, int);
319 #ifdef SMP
320 static int tdq_move(struct tdq *, struct tdq *);
321 static int tdq_idled(struct tdq *);
322 static void tdq_notify(struct tdq *, struct thread *);
323 static struct thread *tdq_steal(struct tdq *, int);
324 static struct thread *runq_steal(struct runq *, int);
325 static int sched_pickcpu(struct thread *, int);
326 static void sched_balance(void);
327 static int sched_balance_pair(struct tdq *, struct tdq *);
328 static inline struct tdq *sched_setcpu(struct thread *, int, int);
329 static inline void thread_unblock_switch(struct thread *, struct mtx *);
330 static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int);
331 static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS);
332 static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb,
333  struct cpu_group *cg, int indent);
334 #endif
335 
336 static void sched_setup(void *dummy);
337 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
338 
339 static void sched_initticks(void *dummy);
340 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks,
341  NULL);
342 
343 SDT_PROVIDER_DEFINE(sched);
344 
345 SDT_PROBE_DEFINE3(sched, , , change__pri, "struct thread *",
346  "struct proc *", "uint8_t");
347 SDT_PROBE_DEFINE3(sched, , , dequeue, "struct thread *",
348  "struct proc *", "void *");
349 SDT_PROBE_DEFINE4(sched, , , enqueue, "struct thread *",
350  "struct proc *", "void *", "int");
351 SDT_PROBE_DEFINE4(sched, , , lend__pri, "struct thread *",
352  "struct proc *", "uint8_t", "struct thread *");
353 SDT_PROBE_DEFINE2(sched, , , load__change, "int", "int");
354 SDT_PROBE_DEFINE2(sched, , , off__cpu, "struct thread *",
355  "struct proc *");
356 SDT_PROBE_DEFINE(sched, , , on__cpu);
357 SDT_PROBE_DEFINE(sched, , , remain__cpu);
358 SDT_PROBE_DEFINE2(sched, , , surrender, "struct thread *",
359  "struct proc *");
360 
361 /*
362  * Print the threads waiting on a run-queue.
363  */
364 static void
365 runq_print(struct runq *rq)
366 {
367  struct rqhead *rqh;
368  struct thread *td;
369  int pri;
370  int j;
371  int i;
372 
373  for (i = 0; i < RQB_LEN; i++) {
374  printf("\t\trunq bits %d 0x%zx\n",
375  i, rq->rq_status.rqb_bits[i]);
376  for (j = 0; j < RQB_BPW; j++)
377  if (rq->rq_status.rqb_bits[i] & (1ul << j)) {
378  pri = j + (i << RQB_L2BPW);
379  rqh = &rq->rq_queues[pri];
380  TAILQ_FOREACH(td, rqh, td_runq) {
381  printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n",
382  td, td->td_name, td->td_priority,
383  td->td_rqindex, pri);
384  }
385  }
386  }
387 }
388 
389 /*
390  * Print the status of a per-cpu thread queue. Should be a ddb show cmd.
391  */
392 void
393 tdq_print(int cpu)
394 {
395  struct tdq *tdq;
396 
397  tdq = TDQ_CPU(cpu);
398 
399  printf("tdq %d:\n", TDQ_ID(tdq));
400  printf("\tlock %p\n", TDQ_LOCKPTR(tdq));
401  printf("\tLock name: %s\n", tdq->tdq_name);
402  printf("\tload: %d\n", tdq->tdq_load);
403  printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt);
404  printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt);
405  printf("\ttimeshare idx: %d\n", tdq->tdq_idx);
406  printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx);
407  printf("\tload transferable: %d\n", tdq->tdq_transferable);
408  printf("\tlowest priority: %d\n", tdq->tdq_lowpri);
409  printf("\trealtime runq:\n");
410  runq_print(&tdq->tdq_realtime);
411  printf("\ttimeshare runq:\n");
412  runq_print(&tdq->tdq_timeshare);
413  printf("\tidle runq:\n");
414  runq_print(&tdq->tdq_idle);
415 }
416 
417 static inline int
418 sched_shouldpreempt(int pri, int cpri, int remote)
419 {
420  /*
421  * If the new priority is not better than the current priority there is
422  * nothing to do.
423  */
424  if (pri >= cpri)
425  return (0);
426  /*
427  * Always preempt idle.
428  */
429  if (cpri >= PRI_MIN_IDLE)
430  return (1);
431  /*
432  * If preemption is disabled don't preempt others.
433  */
434  if (preempt_thresh == 0)
435  return (0);
436  /*
437  * Preempt if we exceed the threshold.
438  */
439  if (pri <= preempt_thresh)
440  return (1);
441  /*
442  * If we're interactive or better and there is non-interactive
443  * or worse running preempt only remote processors.
444  */
445  if (remote && pri <= PRI_MAX_INTERACT && cpri > PRI_MAX_INTERACT)
446  return (1);
447  return (0);
448 }
449 
450 /*
451  * Add a thread to the actual run-queue. Keeps transferable counts up to
452  * date with what is actually on the run-queue. Selects the correct
453  * queue position for timeshare threads.
454  */
455 static __inline void
456 tdq_runq_add(struct tdq *tdq, struct thread *td, int flags)
457 {
458  struct td_sched *ts;
459  u_char pri;
460 
461  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
462  THREAD_LOCK_ASSERT(td, MA_OWNED);
463 
464  pri = td->td_priority;
465  ts = td_get_sched(td);
466  TD_SET_RUNQ(td);
467  if (THREAD_CAN_MIGRATE(td)) {
468  tdq->tdq_transferable++;
469  ts->ts_flags |= TSF_XFERABLE;
470  }
471  if (pri < PRI_MIN_BATCH) {
472  ts->ts_runq = &tdq->tdq_realtime;
473  } else if (pri <= PRI_MAX_BATCH) {
474  ts->ts_runq = &tdq->tdq_timeshare;
475  KASSERT(pri <= PRI_MAX_BATCH && pri >= PRI_MIN_BATCH,
476  ("Invalid priority %d on timeshare runq", pri));
477  /*
478  * This queue contains only priorities between MIN and MAX
479  * realtime. Use the whole queue to represent these values.
480  */
481  if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) {
482  pri = RQ_NQS * (pri - PRI_MIN_BATCH) / PRI_BATCH_RANGE;
483  pri = (pri + tdq->tdq_idx) % RQ_NQS;
484  /*
485  * This effectively shortens the queue by one so we
486  * can have a one slot difference between idx and
487  * ridx while we wait for threads to drain.
488  */
489  if (tdq->tdq_ridx != tdq->tdq_idx &&
490  pri == tdq->tdq_ridx)
491  pri = (unsigned char)(pri - 1) % RQ_NQS;
492  } else
493  pri = tdq->tdq_ridx;
494  runq_add_pri(ts->ts_runq, td, pri, flags);
495  return;
496  } else
497  ts->ts_runq = &tdq->tdq_idle;
498  runq_add(ts->ts_runq, td, flags);
499 }
500 
501 /*
502  * Remove a thread from a run-queue. This typically happens when a thread
503  * is selected to run. Running threads are not on the queue and the
504  * transferable count does not reflect them.
505  */
506 static __inline void
507 tdq_runq_rem(struct tdq *tdq, struct thread *td)
508 {
509  struct td_sched *ts;
510 
511  ts = td_get_sched(td);
512  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
513  KASSERT(ts->ts_runq != NULL,
514  ("tdq_runq_remove: thread %p null ts_runq", td));
515  if (ts->ts_flags & TSF_XFERABLE) {
516  tdq->tdq_transferable--;
517  ts->ts_flags &= ~TSF_XFERABLE;
518  }
519  if (ts->ts_runq == &tdq->tdq_timeshare) {
520  if (tdq->tdq_idx != tdq->tdq_ridx)
521  runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx);
522  else
523  runq_remove_idx(ts->ts_runq, td, NULL);
524  } else
525  runq_remove(ts->ts_runq, td);
526 }
527 
528 /*
529  * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load
530  * for this thread to the referenced thread queue.
531  */
532 static void
533 tdq_load_add(struct tdq *tdq, struct thread *td)
534 {
535 
536  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
537  THREAD_LOCK_ASSERT(td, MA_OWNED);
538 
539  tdq->tdq_load++;
540  if ((td->td_flags & TDF_NOLOAD) == 0)
541  tdq->tdq_sysload++;
542  KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
543  SDT_PROBE2(sched, , , load__change, (int)TDQ_ID(tdq), tdq->tdq_load);
544 }
545 
546 /*
547  * Remove the load from a thread that is transitioning to a sleep state or
548  * exiting.
549  */
550 static void
551 tdq_load_rem(struct tdq *tdq, struct thread *td)
552 {
553 
554  THREAD_LOCK_ASSERT(td, MA_OWNED);
555  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
556  KASSERT(tdq->tdq_load != 0,
557  ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq)));
558 
559  tdq->tdq_load--;
560  if ((td->td_flags & TDF_NOLOAD) == 0)
561  tdq->tdq_sysload--;
562  KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
563  SDT_PROBE2(sched, , , load__change, (int)TDQ_ID(tdq), tdq->tdq_load);
564 }
565 
566 /*
567  * Bound timeshare latency by decreasing slice size as load increases. We
568  * consider the maximum latency as the sum of the threads waiting to run
569  * aside from curthread and target no more than sched_slice latency but
570  * no less than sched_slice_min runtime.
571  */
572 static inline int
573 tdq_slice(struct tdq *tdq)
574 {
575  int load;
576 
577  /*
578  * It is safe to use sys_load here because this is called from
579  * contexts where timeshare threads are running and so there
580  * cannot be higher priority load in the system.
581  */
582  load = tdq->tdq_sysload - 1;
583  if (load >= SCHED_SLICE_MIN_DIVISOR)
584  return (sched_slice_min);
585  if (load <= 1)
586  return (sched_slice);
587  return (sched_slice / load);
588 }
589 
590 /*
591  * Set lowpri to its exact value by searching the run-queue and
592  * evaluating curthread. curthread may be passed as an optimization.
593  */
594 static void
595 tdq_setlowpri(struct tdq *tdq, struct thread *ctd)
596 {
597  struct thread *td;
598 
599  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
600  if (ctd == NULL)
601  ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread;
602  td = tdq_choose(tdq);
603  if (td == NULL || td->td_priority > ctd->td_priority)
604  tdq->tdq_lowpri = ctd->td_priority;
605  else
606  tdq->tdq_lowpri = td->td_priority;
607 }
608 
609 #ifdef SMP
610 /*
611  * We need some randomness. Implement a classic Linear Congruential
612  * Generator X_{n+1}=(aX_n+c) mod m. These values are optimized for
613  * m = 2^32, a = 69069 and c = 5. We only return the upper 16 bits
614  * of the random state (in the low bits of our answer) to keep
615  * the maximum randomness.
616  */
617 static uint32_t
618 sched_random(void)
619 {
620  uint32_t *rndptr;
621 
622  rndptr = DPCPU_PTR(randomval);
623  *rndptr = *rndptr * 69069 + 5;
624 
625  return (*rndptr >> 16);
626 }
627 
628 struct cpu_search {
629  cpuset_t cs_mask;
630  u_int cs_prefer;
631  int cs_pri; /* Min priority for low. */
632  int cs_limit; /* Max load for low, min load for high. */
633  int cs_cpu;
634  int cs_load;
635 };
636 
637 #define CPU_SEARCH_LOWEST 0x1
638 #define CPU_SEARCH_HIGHEST 0x2
639 #define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST)
640 
641 #define CPUSET_FOREACH(cpu, mask) \
642  for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++) \
643  if (CPU_ISSET(cpu, &mask))
644 
645 static __always_inline int cpu_search(const struct cpu_group *cg,
646  struct cpu_search *low, struct cpu_search *high, const int match);
647 int __noinline cpu_search_lowest(const struct cpu_group *cg,
648  struct cpu_search *low);
649 int __noinline cpu_search_highest(const struct cpu_group *cg,
650  struct cpu_search *high);
651 int __noinline cpu_search_both(const struct cpu_group *cg,
652  struct cpu_search *low, struct cpu_search *high);
653 
654 /*
655  * Search the tree of cpu_groups for the lowest or highest loaded cpu
656  * according to the match argument. This routine actually compares the
657  * load on all paths through the tree and finds the least loaded cpu on
658  * the least loaded path, which may differ from the least loaded cpu in
659  * the system. This balances work among caches and busses.
660  *
661  * This inline is instantiated in three forms below using constants for the
662  * match argument. It is reduced to the minimum set for each case. It is
663  * also recursive to the depth of the tree.
664  */
665 static __always_inline int
666 cpu_search(const struct cpu_group *cg, struct cpu_search *low,
667  struct cpu_search *high, const int match)
668 {
669  struct cpu_search lgroup;
670  struct cpu_search hgroup;
671  cpuset_t cpumask;
672  struct cpu_group *child;
673  struct tdq *tdq;
674  int cpu, i, hload, lload, load, total, rnd;
675 
676  total = 0;
677  cpumask = cg->cg_mask;
678  if (match & CPU_SEARCH_LOWEST) {
679  lload = INT_MAX;
680  lgroup = *low;
681  }
682  if (match & CPU_SEARCH_HIGHEST) {
683  hload = INT_MIN;
684  hgroup = *high;
685  }
686 
687  /* Iterate through the child CPU groups and then remaining CPUs. */
688  for (i = cg->cg_children, cpu = mp_maxid; ; ) {
689  if (i == 0) {
690 #ifdef HAVE_INLINE_FFSL
691  cpu = CPU_FFS(&cpumask) - 1;
692 #else
693  while (cpu >= 0 && !CPU_ISSET(cpu, &cpumask))
694  cpu--;
695 #endif
696  if (cpu < 0)
697  break;
698  child = NULL;
699  } else
700  child = &cg->cg_child[i - 1];
701 
702  if (match & CPU_SEARCH_LOWEST)
703  lgroup.cs_cpu = -1;
704  if (match & CPU_SEARCH_HIGHEST)
705  hgroup.cs_cpu = -1;
706  if (child) { /* Handle child CPU group. */
707  CPU_NAND(&cpumask, &child->cg_mask);
708  switch (match) {
709  case CPU_SEARCH_LOWEST:
710  load = cpu_search_lowest(child, &lgroup);
711  break;
712  case CPU_SEARCH_HIGHEST:
713  load = cpu_search_highest(child, &hgroup);
714  break;
715  case CPU_SEARCH_BOTH:
716  load = cpu_search_both(child, &lgroup, &hgroup);
717  break;
718  }
719  } else { /* Handle child CPU. */
720  CPU_CLR(cpu, &cpumask);
721  tdq = TDQ_CPU(cpu);
722  load = tdq->tdq_load * 256;
723  rnd = sched_random() % 32;
724  if (match & CPU_SEARCH_LOWEST) {
725  if (cpu == low->cs_prefer)
726  load -= 64;
727  /* If that CPU is allowed and get data. */
728  if (tdq->tdq_lowpri > lgroup.cs_pri &&
729  tdq->tdq_load <= lgroup.cs_limit &&
730  CPU_ISSET(cpu, &lgroup.cs_mask)) {
731  lgroup.cs_cpu = cpu;
732  lgroup.cs_load = load - rnd;
733  }
734  }
735  if (match & CPU_SEARCH_HIGHEST)
736  if (tdq->tdq_load >= hgroup.cs_limit &&
737  tdq->tdq_transferable &&
738  CPU_ISSET(cpu, &hgroup.cs_mask)) {
739  hgroup.cs_cpu = cpu;
740  hgroup.cs_load = load - rnd;
741  }
742  }
743  total += load;
744 
745  /* We have info about child item. Compare it. */
746  if (match & CPU_SEARCH_LOWEST) {
747  if (lgroup.cs_cpu >= 0 &&
748  (load < lload ||
749  (load == lload && lgroup.cs_load < low->cs_load))) {
750  lload = load;
751  low->cs_cpu = lgroup.cs_cpu;
752  low->cs_load = lgroup.cs_load;
753  }
754  }
755  if (match & CPU_SEARCH_HIGHEST)
756  if (hgroup.cs_cpu >= 0 &&
757  (load > hload ||
758  (load == hload && hgroup.cs_load > high->cs_load))) {
759  hload = load;
760  high->cs_cpu = hgroup.cs_cpu;
761  high->cs_load = hgroup.cs_load;
762  }
763  if (child) {
764  i--;
765  if (i == 0 && CPU_EMPTY(&cpumask))
766  break;
767  }
768 #ifndef HAVE_INLINE_FFSL
769  else
770  cpu--;
771 #endif
772  }
773  return (total);
774 }
775 
776 /*
777  * cpu_search instantiations must pass constants to maintain the inline
778  * optimization.
779  */
780 int
781 cpu_search_lowest(const struct cpu_group *cg, struct cpu_search *low)
782 {
783  return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST);
784 }
785 
786 int
787 cpu_search_highest(const struct cpu_group *cg, struct cpu_search *high)
788 {
789  return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST);
790 }
791 
792 int
793 cpu_search_both(const struct cpu_group *cg, struct cpu_search *low,
794  struct cpu_search *high)
795 {
796  return cpu_search(cg, low, high, CPU_SEARCH_BOTH);
797 }
798 
799 /*
800  * Find the cpu with the least load via the least loaded path that has a
801  * lowpri greater than pri pri. A pri of -1 indicates any priority is
802  * acceptable.
803  */
804 static inline int
805 sched_lowest(const struct cpu_group *cg, cpuset_t mask, int pri, int maxload,
806  int prefer)
807 {
808  struct cpu_search low;
809 
810  low.cs_cpu = -1;
811  low.cs_prefer = prefer;
812  low.cs_mask = mask;
813  low.cs_pri = pri;
814  low.cs_limit = maxload;
815  cpu_search_lowest(cg, &low);
816  return low.cs_cpu;
817 }
818 
819 /*
820  * Find the cpu with the highest load via the highest loaded path.
821  */
822 static inline int
823 sched_highest(const struct cpu_group *cg, cpuset_t mask, int minload)
824 {
825  struct cpu_search high;
826 
827  high.cs_cpu = -1;
828  high.cs_mask = mask;
829  high.cs_limit = minload;
830  cpu_search_highest(cg, &high);
831  return high.cs_cpu;
832 }
833 
834 static void
835 sched_balance_group(struct cpu_group *cg)
836 {
837  cpuset_t hmask, lmask;
838  int high, low, anylow;
839 
840  CPU_FILL(&hmask);
841  for (;;) {
842  high = sched_highest(cg, hmask, 1);
843  /* Stop if there is no more CPU with transferrable threads. */
844  if (high == -1)
845  break;
846  CPU_CLR(high, &hmask);
847  CPU_COPY(&hmask, &lmask);
848  /* Stop if there is no more CPU left for low. */
849  if (CPU_EMPTY(&lmask))
850  break;
851  anylow = 1;
852 nextlow:
853  low = sched_lowest(cg, lmask, -1,
854  TDQ_CPU(high)->tdq_load - 1, high);
855  /* Stop if we looked well and found no less loaded CPU. */
856  if (anylow && low == -1)
857  break;
858  /* Go to next high if we found no less loaded CPU. */
859  if (low == -1)
860  continue;
861  /* Transfer thread from high to low. */
862  if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low))) {
863  /* CPU that got thread can no longer be a donor. */
864  CPU_CLR(low, &hmask);
865  } else {
866  /*
867  * If failed, then there is no threads on high
868  * that can run on this low. Drop low from low
869  * mask and look for different one.
870  */
871  CPU_CLR(low, &lmask);
872  anylow = 0;
873  goto nextlow;
874  }
875  }
876 }
877 
878 static void
879 sched_balance(void)
880 {
881  struct tdq *tdq;
882 
883  if (smp_started == 0 || rebalance == 0)
884  return;
885 
886  balance_ticks = max(balance_interval / 2, 1) +
887  (sched_random() % balance_interval);
888  tdq = TDQ_SELF();
889  TDQ_UNLOCK(tdq);
890  sched_balance_group(cpu_top);
891  TDQ_LOCK(tdq);
892 }
893 
894 /*
895  * Lock two thread queues using their address to maintain lock order.
896  */
897 static void
898 tdq_lock_pair(struct tdq *one, struct tdq *two)
899 {
900  if (one < two) {
901  TDQ_LOCK(one);
902  TDQ_LOCK_FLAGS(two, MTX_DUPOK);
903  } else {
904  TDQ_LOCK(two);
905  TDQ_LOCK_FLAGS(one, MTX_DUPOK);
906  }
907 }
908 
909 /*
910  * Unlock two thread queues. Order is not important here.
911  */
912 static void
913 tdq_unlock_pair(struct tdq *one, struct tdq *two)
914 {
915  TDQ_UNLOCK(one);
916  TDQ_UNLOCK(two);
917 }
918 
919 /*
920  * Transfer load between two imbalanced thread queues.
921  */
922 static int
923 sched_balance_pair(struct tdq *high, struct tdq *low)
924 {
925  int moved;
926  int cpu;
927 
928  tdq_lock_pair(high, low);
929  moved = 0;
930  /*
931  * Determine what the imbalance is and then adjust that to how many
932  * threads we actually have to give up (transferable).
933  */
934  if (high->tdq_transferable != 0 && high->tdq_load > low->tdq_load &&
935  (moved = tdq_move(high, low)) > 0) {
936  /*
937  * In case the target isn't the current cpu IPI it to force a
938  * reschedule with the new workload.
939  */
940  cpu = TDQ_ID(low);
941  if (cpu != PCPU_GET(cpuid))
942  ipi_cpu(cpu, IPI_PREEMPT);
943  }
944  tdq_unlock_pair(high, low);
945  return (moved);
946 }
947 
948 /*
949  * Move a thread from one thread queue to another.
950  */
951 static int
952 tdq_move(struct tdq *from, struct tdq *to)
953 {
954  struct td_sched *ts;
955  struct thread *td;
956  struct tdq *tdq;
957  int cpu;
958 
959  TDQ_LOCK_ASSERT(from, MA_OWNED);
960  TDQ_LOCK_ASSERT(to, MA_OWNED);
961 
962  tdq = from;
963  cpu = TDQ_ID(to);
964  td = tdq_steal(tdq, cpu);
965  if (td == NULL)
966  return (0);
967  ts = td_get_sched(td);
968  /*
969  * Although the run queue is locked the thread may be blocked. Lock
970  * it to clear this and acquire the run-queue lock.
971  */
972  thread_lock(td);
973  /* Drop recursive lock on from acquired via thread_lock(). */
974  TDQ_UNLOCK(from);
975  sched_rem(td);
976  ts->ts_cpu = cpu;
977  td->td_lock = TDQ_LOCKPTR(to);
978  tdq_add(to, td, SRQ_YIELDING);
979  return (1);
980 }
981 
982 /*
983  * This tdq has idled. Try to steal a thread from another cpu and switch
984  * to it.
985  */
986 static int
987 tdq_idled(struct tdq *tdq)
988 {
989  struct cpu_group *cg;
990  struct tdq *steal;
991  cpuset_t mask;
992  int thresh;
993  int cpu;
994 
995  if (smp_started == 0 || steal_idle == 0)
996  return (1);
997  CPU_FILL(&mask);
998  CPU_CLR(PCPU_GET(cpuid), &mask);
999  /* We don't want to be preempted while we're iterating. */
1000  spinlock_enter();
1001  for (cg = tdq->tdq_cg; cg != NULL; ) {
1002  if ((cg->cg_flags & CG_FLAG_THREAD) == 0)
1003  thresh = steal_thresh;
1004  else
1005  thresh = 1;
1006  cpu = sched_highest(cg, mask, thresh);
1007  if (cpu == -1) {
1008  cg = cg->cg_parent;
1009  continue;
1010  }
1011  steal = TDQ_CPU(cpu);
1012  CPU_CLR(cpu, &mask);
1013  tdq_lock_pair(tdq, steal);
1014  if (steal->tdq_load < thresh || steal->tdq_transferable == 0) {
1015  tdq_unlock_pair(tdq, steal);
1016  continue;
1017  }
1018  /*
1019  * If a thread was added while interrupts were disabled don't
1020  * steal one here. If we fail to acquire one due to affinity
1021  * restrictions loop again with this cpu removed from the
1022  * set.
1023  */
1024  if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) {
1025  tdq_unlock_pair(tdq, steal);
1026  continue;
1027  }
1028  spinlock_exit();
1029  TDQ_UNLOCK(steal);
1030  mi_switch(SW_VOL | SWT_IDLE, NULL);
1031  thread_unlock(curthread);
1032 
1033  return (0);
1034  }
1035  spinlock_exit();
1036  return (1);
1037 }
1038 
1039 /*
1040  * Notify a remote cpu of new work. Sends an IPI if criteria are met.
1041  */
1042 static void
1043 tdq_notify(struct tdq *tdq, struct thread *td)
1044 {
1045  struct thread *ctd;
1046  int pri;
1047  int cpu;
1048 
1049  if (tdq->tdq_ipipending)
1050  return;
1051  cpu = td_get_sched(td)->ts_cpu;
1052  pri = td->td_priority;
1053  ctd = pcpu_find(cpu)->pc_curthread;
1054  if (!sched_shouldpreempt(pri, ctd->td_priority, 1))
1055  return;
1056 
1057  /*
1058  * Make sure that our caller's earlier update to tdq_load is
1059  * globally visible before we read tdq_cpu_idle. Idle thread
1060  * accesses both of them without locks, and the order is important.
1061  */
1062  atomic_thread_fence_seq_cst();
1063 
1064  if (TD_IS_IDLETHREAD(ctd)) {
1065  /*
1066  * If the MD code has an idle wakeup routine try that before
1067  * falling back to IPI.
1068  */
1069  if (!tdq->tdq_cpu_idle || cpu_idle_wakeup(cpu))
1070  return;
1071  }
1072  tdq->tdq_ipipending = 1;
1073  ipi_cpu(cpu, IPI_PREEMPT);
1074 }
1075 
1076 /*
1077  * Steals load from a timeshare queue. Honors the rotating queue head
1078  * index.
1079  */
1080 static struct thread *
1081 runq_steal_from(struct runq *rq, int cpu, u_char start)
1082 {
1083  struct rqbits *rqb;
1084  struct rqhead *rqh;
1085  struct thread *td, *first;
1086  int bit;
1087  int i;
1088 
1089  rqb = &rq->rq_status;
1090  bit = start & (RQB_BPW -1);
1091  first = NULL;
1092 again:
1093  for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) {
1094  if (rqb->rqb_bits[i] == 0)
1095  continue;
1096  if (bit == 0)
1097  bit = RQB_FFS(rqb->rqb_bits[i]);
1098  for (; bit < RQB_BPW; bit++) {
1099  if ((rqb->rqb_bits[i] & (1ul << bit)) == 0)
1100  continue;
1101  rqh = &rq->rq_queues[bit + (i << RQB_L2BPW)];
1102  TAILQ_FOREACH(td, rqh, td_runq) {
1103  if (first && THREAD_CAN_MIGRATE(td) &&
1104  THREAD_CAN_SCHED(td, cpu))
1105  return (td);
1106  first = td;
1107  }
1108  }
1109  }
1110  if (start != 0) {
1111  start = 0;
1112  goto again;
1113  }
1114 
1115  if (first && THREAD_CAN_MIGRATE(first) &&
1116  THREAD_CAN_SCHED(first, cpu))
1117  return (first);
1118  return (NULL);
1119 }
1120 
1121 /*
1122  * Steals load from a standard linear queue.
1123  */
1124 static struct thread *
1125 runq_steal(struct runq *rq, int cpu)
1126 {
1127  struct rqhead *rqh;
1128  struct rqbits *rqb;
1129  struct thread *td;
1130  int word;
1131  int bit;
1132 
1133  rqb = &rq->rq_status;
1134  for (word = 0; word < RQB_LEN; word++) {
1135  if (rqb->rqb_bits[word] == 0)
1136  continue;
1137  for (bit = 0; bit < RQB_BPW; bit++) {
1138  if ((rqb->rqb_bits[word] & (1ul << bit)) == 0)
1139  continue;
1140  rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)];
1141  TAILQ_FOREACH(td, rqh, td_runq)
1142  if (THREAD_CAN_MIGRATE(td) &&
1143  THREAD_CAN_SCHED(td, cpu))
1144  return (td);
1145  }
1146  }
1147  return (NULL);
1148 }
1149 
1150 /*
1151  * Attempt to steal a thread in priority order from a thread queue.
1152  */
1153 static struct thread *
1154 tdq_steal(struct tdq *tdq, int cpu)
1155 {
1156  struct thread *td;
1157 
1158  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1159  if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL)
1160  return (td);
1161  if ((td = runq_steal_from(&tdq->tdq_timeshare,
1162  cpu, tdq->tdq_ridx)) != NULL)
1163  return (td);
1164  return (runq_steal(&tdq->tdq_idle, cpu));
1165 }
1166 
1167 /*
1168  * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the
1169  * current lock and returns with the assigned queue locked.
1170  */
1171 static inline struct tdq *
1172 sched_setcpu(struct thread *td, int cpu, int flags)
1173 {
1174 
1175  struct tdq *tdq;
1176 
1177  THREAD_LOCK_ASSERT(td, MA_OWNED);
1178  tdq = TDQ_CPU(cpu);
1179  td_get_sched(td)->ts_cpu = cpu;
1180  /*
1181  * If the lock matches just return the queue.
1182  */
1183  if (td->td_lock == TDQ_LOCKPTR(tdq))
1184  return (tdq);
1185 #ifdef notyet
1186  /*
1187  * If the thread isn't running its lockptr is a
1188  * turnstile or a sleepqueue. We can just lock_set without
1189  * blocking.
1190  */
1191  if (TD_CAN_RUN(td)) {
1192  TDQ_LOCK(tdq);
1193  thread_lock_set(td, TDQ_LOCKPTR(tdq));
1194  return (tdq);
1195  }
1196 #endif
1197  /*
1198  * The hard case, migration, we need to block the thread first to
1199  * prevent order reversals with other cpus locks.
1200  */
1201  spinlock_enter();
1202  thread_lock_block(td);
1203  TDQ_LOCK(tdq);
1204  thread_lock_unblock(td, TDQ_LOCKPTR(tdq));
1205  spinlock_exit();
1206  return (tdq);
1207 }
1208 
1209 SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding");
1210 SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity");
1211 SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity");
1212 SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load");
1213 SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu");
1214 SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration");
1215 
1216 static int
1217 sched_pickcpu(struct thread *td, int flags)
1218 {
1219  struct cpu_group *cg, *ccg;
1220  struct td_sched *ts;
1221  struct tdq *tdq;
1222  cpuset_t mask;
1223  int cpu, pri, self;
1224 
1225  self = PCPU_GET(cpuid);
1226  ts = td_get_sched(td);
1227  if (smp_started == 0)
1228  return (self);
1229  /*
1230  * Don't migrate a running thread from sched_switch().
1231  */
1232  if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td))
1233  return (ts->ts_cpu);
1234  /*
1235  * Prefer to run interrupt threads on the processors that generate
1236  * the interrupt.
1237  */
1238  pri = td->td_priority;
1239  if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) &&
1240  curthread->td_intr_nesting_level && ts->ts_cpu != self) {
1241  SCHED_STAT_INC(pickcpu_intrbind);
1242  ts->ts_cpu = self;
1243  if (TDQ_CPU(self)->tdq_lowpri > pri) {
1244  SCHED_STAT_INC(pickcpu_affinity);
1245  return (ts->ts_cpu);
1246  }
1247  }
1248  /*
1249  * If the thread can run on the last cpu and the affinity has not
1250  * expired or it is idle run it there.
1251  */
1252  tdq = TDQ_CPU(ts->ts_cpu);
1253  cg = tdq->tdq_cg;
1254  if (THREAD_CAN_SCHED(td, ts->ts_cpu) &&
1255  tdq->tdq_lowpri >= PRI_MIN_IDLE &&
1256  SCHED_AFFINITY(ts, CG_SHARE_L2)) {
1257  if (cg->cg_flags & CG_FLAG_THREAD) {
1258  CPUSET_FOREACH(cpu, cg->cg_mask) {
1259  if (TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE)
1260  break;
1261  }
1262  } else
1263  cpu = INT_MAX;
1264  if (cpu > mp_maxid) {
1265  SCHED_STAT_INC(pickcpu_idle_affinity);
1266  return (ts->ts_cpu);
1267  }
1268  }
1269  /*
1270  * Search for the last level cache CPU group in the tree.
1271  * Skip caches with expired affinity time and SMT groups.
1272  * Affinity to higher level caches will be handled less aggressively.
1273  */
1274  for (ccg = NULL; cg != NULL; cg = cg->cg_parent) {
1275  if (cg->cg_flags & CG_FLAG_THREAD)
1276  continue;
1277  if (!SCHED_AFFINITY(ts, cg->cg_level))
1278  continue;
1279  ccg = cg;
1280  }
1281  if (ccg != NULL)
1282  cg = ccg;
1283  cpu = -1;
1284  /* Search the group for the less loaded idle CPU we can run now. */
1285  mask = td->td_cpuset->cs_mask;
1286  if (cg != NULL && cg != cpu_top &&
1287  CPU_CMP(&cg->cg_mask, &cpu_top->cg_mask) != 0)
1288  cpu = sched_lowest(cg, mask, max(pri, PRI_MAX_TIMESHARE),
1289  INT_MAX, ts->ts_cpu);
1290  /* Search globally for the less loaded CPU we can run now. */
1291  if (cpu == -1)
1292  cpu = sched_lowest(cpu_top, mask, pri, INT_MAX, ts->ts_cpu);
1293  /* Search globally for the less loaded CPU. */
1294  if (cpu == -1)
1295  cpu = sched_lowest(cpu_top, mask, -1, INT_MAX, ts->ts_cpu);
1296  KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu."));
1297  /*
1298  * Compare the lowest loaded cpu to current cpu.
1299  */
1300  if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri &&
1301  TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE &&
1302  TDQ_CPU(self)->tdq_load <= TDQ_CPU(cpu)->tdq_load + 1) {
1303  SCHED_STAT_INC(pickcpu_local);
1304  cpu = self;
1305  } else
1306  SCHED_STAT_INC(pickcpu_lowest);
1307  if (cpu != ts->ts_cpu)
1308  SCHED_STAT_INC(pickcpu_migration);
1309  return (cpu);
1310 }
1311 #endif
1312 
1313 /*
1314  * Pick the highest priority task we have and return it.
1315  */
1316 static struct thread *
1317 tdq_choose(struct tdq *tdq)
1318 {
1319  struct thread *td;
1320 
1321  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1322  td = runq_choose(&tdq->tdq_realtime);
1323  if (td != NULL)
1324  return (td);
1325  td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx);
1326  if (td != NULL) {
1327  KASSERT(td->td_priority >= PRI_MIN_BATCH,
1328  ("tdq_choose: Invalid priority on timeshare queue %d",
1329  td->td_priority));
1330  return (td);
1331  }
1332  td = runq_choose(&tdq->tdq_idle);
1333  if (td != NULL) {
1334  KASSERT(td->td_priority >= PRI_MIN_IDLE,
1335  ("tdq_choose: Invalid priority on idle queue %d",
1336  td->td_priority));
1337  return (td);
1338  }
1339 
1340  return (NULL);
1341 }
1342 
1343 /*
1344  * Initialize a thread queue.
1345  */
1346 static void
1347 tdq_setup(struct tdq *tdq)
1348 {
1349 
1350  if (bootverbose)
1351  printf("ULE: setup cpu %d\n", TDQ_ID(tdq));
1352  runq_init(&tdq->tdq_realtime);
1353  runq_init(&tdq->tdq_timeshare);
1354  runq_init(&tdq->tdq_idle);
1355  snprintf(tdq->tdq_name, sizeof(tdq->tdq_name),
1356  "sched lock %d", (int)TDQ_ID(tdq));
1357  mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock",
1358  MTX_SPIN | MTX_RECURSE);
1359 #ifdef KTR
1360  snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname),
1361  "CPU %d load", (int)TDQ_ID(tdq));
1362 #endif
1363 }
1364 
1365 #ifdef SMP
1366 static void
1367 sched_setup_smp(void)
1368 {
1369  struct tdq *tdq;
1370  int i;
1371 
1372  cpu_top = smp_topo();
1373  CPU_FOREACH(i) {
1374  tdq = TDQ_CPU(i);
1375  tdq_setup(tdq);
1376  tdq->tdq_cg = smp_topo_find(cpu_top, i);
1377  if (tdq->tdq_cg == NULL)
1378  panic("Can't find cpu group for %d\n", i);
1379  }
1380  balance_tdq = TDQ_SELF();
1381  sched_balance();
1382 }
1383 #endif
1384 
1385 /*
1386  * Setup the thread queues and initialize the topology based on MD
1387  * information.
1388  */
1389 static void
1391 {
1392  struct tdq *tdq;
1393 
1394  tdq = TDQ_SELF();
1395 #ifdef SMP
1396  sched_setup_smp();
1397 #else
1398  tdq_setup(tdq);
1399 #endif
1400 
1401  /* Add thread0's load since it's running. */
1402  TDQ_LOCK(tdq);
1403  thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF());
1404  tdq_load_add(tdq, &thread0);
1405  tdq->tdq_lowpri = thread0.td_priority;
1406  TDQ_UNLOCK(tdq);
1407 }
1408 
1409 /*
1410  * This routine determines time constants after stathz and hz are setup.
1411  */
1412 /* ARGSUSED */
1413 static void
1415 {
1416  int incr;
1417 
1418  realstathz = stathz ? stathz : hz;
1419  sched_slice = realstathz / SCHED_SLICE_DEFAULT_DIVISOR;
1420  sched_slice_min = sched_slice / SCHED_SLICE_MIN_DIVISOR;
1421  hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
1422  realstathz);
1423 
1424  /*
1425  * tickincr is shifted out by 10 to avoid rounding errors due to
1426  * hz not being evenly divisible by stathz on all platforms.
1427  */
1428  incr = (hz << SCHED_TICK_SHIFT) / realstathz;
1429  /*
1430  * This does not work for values of stathz that are more than
1431  * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen.
1432  */
1433  if (incr == 0)
1434  incr = 1;
1435  tickincr = incr;
1436 #ifdef SMP
1437  /*
1438  * Set the default balance interval now that we know
1439  * what realstathz is.
1440  */
1441  balance_interval = realstathz;
1442  affinity = SCHED_AFFINITY_DEFAULT;
1443 #endif
1444  if (sched_idlespinthresh < 0)
1445  sched_idlespinthresh = 2 * max(10000, 6 * hz) / realstathz;
1446 }
1447 
1448 
1449 /*
1450  * This is the core of the interactivity algorithm. Determines a score based
1451  * on past behavior. It is the ratio of sleep time to run time scaled to
1452  * a [0, 100] integer. This is the voluntary sleep time of a process, which
1453  * differs from the cpu usage because it does not account for time spent
1454  * waiting on a run-queue. Would be prettier if we had floating point.
1455  *
1456  * When a thread's sleep time is greater than its run time the
1457  * calculation is:
1458  *
1459  * scaling factor
1460  * interactivity score = ---------------------
1461  * sleep time / run time
1462  *
1463  *
1464  * When a thread's run time is greater than its sleep time the
1465  * calculation is:
1466  *
1467  * scaling factor
1468  * interactivity score = --------------------- + scaling factor
1469  * run time / sleep time
1470  */
1471 static int
1472 sched_interact_score(struct thread *td)
1473 {
1474  struct td_sched *ts;
1475  int div;
1476 
1477  ts = td_get_sched(td);
1478  /*
1479  * The score is only needed if this is likely to be an interactive
1480  * task. Don't go through the expense of computing it if there's
1481  * no chance.
1482  */
1483  if (sched_interact <= SCHED_INTERACT_HALF &&
1484  ts->ts_runtime >= ts->ts_slptime)
1485  return (SCHED_INTERACT_HALF);
1486 
1487  if (ts->ts_runtime > ts->ts_slptime) {
1488  div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF);
1489  return (SCHED_INTERACT_HALF +
1490  (SCHED_INTERACT_HALF - (ts->ts_slptime / div)));
1491  }
1492  if (ts->ts_slptime > ts->ts_runtime) {
1493  div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF);
1494  return (ts->ts_runtime / div);
1495  }
1496  /* runtime == slptime */
1497  if (ts->ts_runtime)
1498  return (SCHED_INTERACT_HALF);
1499 
1500  /*
1501  * This can happen if slptime and runtime are 0.
1502  */
1503  return (0);
1504 
1505 }
1506 
1507 /*
1508  * Scale the scheduling priority according to the "interactivity" of this
1509  * process.
1510  */
1511 static void
1512 sched_priority(struct thread *td)
1513 {
1514  int score;
1515  int pri;
1516 
1517  if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
1518  return;
1519  /*
1520  * If the score is interactive we place the thread in the realtime
1521  * queue with a priority that is less than kernel and interrupt
1522  * priorities. These threads are not subject to nice restrictions.
1523  *
1524  * Scores greater than this are placed on the normal timeshare queue
1525  * where the priority is partially decided by the most recent cpu
1526  * utilization and the rest is decided by nice value.
1527  *
1528  * The nice value of the process has a linear effect on the calculated
1529  * score. Negative nice values make it easier for a thread to be
1530  * considered interactive.
1531  */
1532  score = imax(0, sched_interact_score(td) + td->td_proc->p_nice);
1533  if (score < sched_interact) {
1534  pri = PRI_MIN_INTERACT;
1535  pri += ((PRI_MAX_INTERACT - PRI_MIN_INTERACT + 1) /
1536  sched_interact) * score;
1537  KASSERT(pri >= PRI_MIN_INTERACT && pri <= PRI_MAX_INTERACT,
1538  ("sched_priority: invalid interactive priority %d score %d",
1539  pri, score));
1540  } else {
1541  pri = SCHED_PRI_MIN;
1542  if (td_get_sched(td)->ts_ticks)
1543  pri += min(SCHED_PRI_TICKS(td_get_sched(td)),
1544  SCHED_PRI_RANGE - 1);
1545  pri += SCHED_PRI_NICE(td->td_proc->p_nice);
1546  KASSERT(pri >= PRI_MIN_BATCH && pri <= PRI_MAX_BATCH,
1547  ("sched_priority: invalid priority %d: nice %d, "
1548  "ticks %d ftick %d ltick %d tick pri %d",
1549  pri, td->td_proc->p_nice, td_get_sched(td)->ts_ticks,
1550  td_get_sched(td)->ts_ftick, td_get_sched(td)->ts_ltick,
1551  SCHED_PRI_TICKS(td_get_sched(td))));
1552  }
1553  sched_user_prio(td, pri);
1554 
1555  return;
1556 }
1557 
1558 /*
1559  * This routine enforces a maximum limit on the amount of scheduling history
1560  * kept. It is called after either the slptime or runtime is adjusted. This
1561  * function is ugly due to integer math.
1562  */
1563 static void
1564 sched_interact_update(struct thread *td)
1565 {
1566  struct td_sched *ts;
1567  u_int sum;
1568 
1569  ts = td_get_sched(td);
1570  sum = ts->ts_runtime + ts->ts_slptime;
1571  if (sum < SCHED_SLP_RUN_MAX)
1572  return;
1573  /*
1574  * This only happens from two places:
1575  * 1) We have added an unusual amount of run time from fork_exit.
1576  * 2) We have added an unusual amount of sleep time from sched_sleep().
1577  */
1578  if (sum > SCHED_SLP_RUN_MAX * 2) {
1579  if (ts->ts_runtime > ts->ts_slptime) {
1581  ts->ts_slptime = 1;
1582  } else {
1584  ts->ts_runtime = 1;
1585  }
1586  return;
1587  }
1588  /*
1589  * If we have exceeded by more than 1/5th then the algorithm below
1590  * will not bring us back into range. Dividing by two here forces
1591  * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX]
1592  */
1593  if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) {
1594  ts->ts_runtime /= 2;
1595  ts->ts_slptime /= 2;
1596  return;
1597  }
1598  ts->ts_runtime = (ts->ts_runtime / 5) * 4;
1599  ts->ts_slptime = (ts->ts_slptime / 5) * 4;
1600 }
1601 
1602 /*
1603  * Scale back the interactivity history when a child thread is created. The
1604  * history is inherited from the parent but the thread may behave totally
1605  * differently. For example, a shell spawning a compiler process. We want
1606  * to learn that the compiler is behaving badly very quickly.
1607  */
1608 static void
1609 sched_interact_fork(struct thread *td)
1610 {
1611  struct td_sched *ts;
1612  int ratio;
1613  int sum;
1614 
1615  ts = td_get_sched(td);
1616  sum = ts->ts_runtime + ts->ts_slptime;
1617  if (sum > SCHED_SLP_RUN_FORK) {
1618  ratio = sum / SCHED_SLP_RUN_FORK;
1619  ts->ts_runtime /= ratio;
1620  ts->ts_slptime /= ratio;
1621  }
1622 }
1623 
1624 /*
1625  * Called from proc0_init() to setup the scheduler fields.
1626  */
1627 void
1629 {
1630  struct td_sched *ts0;
1631 
1632  /*
1633  * Set up the scheduler specific parts of thread0.
1634  */
1635  ts0 = td_get_sched(&thread0);
1636  ts0->ts_ltick = ticks;
1637  ts0->ts_ftick = ticks;
1638  ts0->ts_slice = 0;
1639 }
1640 
1641 /*
1642  * This is only somewhat accurate since given many processes of the same
1643  * priority they will switch when their slices run out, which will be
1644  * at most sched_slice stathz ticks.
1645  */
1646 int
1648 {
1649 
1650  /* Convert sched_slice from stathz to hz. */
1651  return (imax(1, (sched_slice * hz + realstathz / 2) / realstathz));
1652 }
1653 
1654 /*
1655  * Update the percent cpu tracking information when it is requested or
1656  * the total history exceeds the maximum. We keep a sliding history of
1657  * tick counts that slowly decays. This is less precise than the 4BSD
1658  * mechanism since it happens with less regular and frequent events.
1659  */
1660 static void
1662 {
1663  int t = ticks;
1664 
1665  if (t - ts->ts_ltick >= SCHED_TICK_TARG) {
1666  ts->ts_ticks = 0;
1667  ts->ts_ftick = t - SCHED_TICK_TARG;
1668  } else if (t - ts->ts_ftick >= SCHED_TICK_MAX) {
1669  ts->ts_ticks = (ts->ts_ticks / (ts->ts_ltick - ts->ts_ftick)) *
1670  (ts->ts_ltick - (t - SCHED_TICK_TARG));
1671  ts->ts_ftick = t - SCHED_TICK_TARG;
1672  }
1673  if (run)
1674  ts->ts_ticks += (t - ts->ts_ltick) << SCHED_TICK_SHIFT;
1675  ts->ts_ltick = t;
1676 }
1677 
1678 /*
1679  * Adjust the priority of a thread. Move it to the appropriate run-queue
1680  * if necessary. This is the back-end for several priority related
1681  * functions.
1682  */
1683 static void
1684 sched_thread_priority(struct thread *td, u_char prio)
1685 {
1686  struct td_sched *ts;
1687  struct tdq *tdq;
1688  int oldpri;
1689 
1690  KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio",
1691  "prio:%d", td->td_priority, "new prio:%d", prio,
1692  KTR_ATTR_LINKED, sched_tdname(curthread));
1693  SDT_PROBE3(sched, , , change__pri, td, td->td_proc, prio);
1694  if (td != curthread && prio < td->td_priority) {
1695  KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread),
1696  "lend prio", "prio:%d", td->td_priority, "new prio:%d",
1697  prio, KTR_ATTR_LINKED, sched_tdname(td));
1698  SDT_PROBE4(sched, , , lend__pri, td, td->td_proc, prio,
1699  curthread);
1700  }
1701  ts = td_get_sched(td);
1702  THREAD_LOCK_ASSERT(td, MA_OWNED);
1703  if (td->td_priority == prio)
1704  return;
1705  /*
1706  * If the priority has been elevated due to priority
1707  * propagation, we may have to move ourselves to a new
1708  * queue. This could be optimized to not re-add in some
1709  * cases.
1710  */
1711  if (TD_ON_RUNQ(td) && prio < td->td_priority) {
1712  sched_rem(td);
1713  td->td_priority = prio;
1714  sched_add(td, SRQ_BORROWING);
1715  return;
1716  }
1717  /*
1718  * If the thread is currently running we may have to adjust the lowpri
1719  * information so other cpus are aware of our current priority.
1720  */
1721  if (TD_IS_RUNNING(td)) {
1722  tdq = TDQ_CPU(ts->ts_cpu);
1723  oldpri = td->td_priority;
1724  td->td_priority = prio;
1725  if (prio < tdq->tdq_lowpri)
1726  tdq->tdq_lowpri = prio;
1727  else if (tdq->tdq_lowpri == oldpri)
1728  tdq_setlowpri(tdq, td);
1729  return;
1730  }
1731  td->td_priority = prio;
1732 }
1733 
1734 /*
1735  * Update a thread's priority when it is lent another thread's
1736  * priority.
1737  */
1738 void
1739 sched_lend_prio(struct thread *td, u_char prio)
1740 {
1741 
1742  td->td_flags |= TDF_BORROWING;
1743  sched_thread_priority(td, prio);
1744 }
1745 
1746 /*
1747  * Restore a thread's priority when priority propagation is
1748  * over. The prio argument is the minimum priority the thread
1749  * needs to have to satisfy other possible priority lending
1750  * requests. If the thread's regular priority is less
1751  * important than prio, the thread will keep a priority boost
1752  * of prio.
1753  */
1754 void
1755 sched_unlend_prio(struct thread *td, u_char prio)
1756 {
1757  u_char base_pri;
1758 
1759  if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
1760  td->td_base_pri <= PRI_MAX_TIMESHARE)
1761  base_pri = td->td_user_pri;
1762  else
1763  base_pri = td->td_base_pri;
1764  if (prio >= base_pri) {
1765  td->td_flags &= ~TDF_BORROWING;
1766  sched_thread_priority(td, base_pri);
1767  } else
1768  sched_lend_prio(td, prio);
1769 }
1770 
1771 /*
1772  * Standard entry for setting the priority to an absolute value.
1773  */
1774 void
1775 sched_prio(struct thread *td, u_char prio)
1776 {
1777  u_char oldprio;
1778 
1779  /* First, update the base priority. */
1780  td->td_base_pri = prio;
1781 
1782  /*
1783  * If the thread is borrowing another thread's priority, don't
1784  * ever lower the priority.
1785  */
1786  if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
1787  return;
1788 
1789  /* Change the real priority. */
1790  oldprio = td->td_priority;
1791  sched_thread_priority(td, prio);
1792 
1793  /*
1794  * If the thread is on a turnstile, then let the turnstile update
1795  * its state.
1796  */
1797  if (TD_ON_LOCK(td) && oldprio != prio)
1798  turnstile_adjust(td, oldprio);
1799 }
1800 
1801 /*
1802  * Set the base user priority, does not effect current running priority.
1803  */
1804 void
1805 sched_user_prio(struct thread *td, u_char prio)
1806 {
1807 
1808  td->td_base_user_pri = prio;
1809  if (td->td_lend_user_pri <= prio)
1810  return;
1811  td->td_user_pri = prio;
1812 }
1813 
1814 void
1815 sched_lend_user_prio(struct thread *td, u_char prio)
1816 {
1817 
1818  THREAD_LOCK_ASSERT(td, MA_OWNED);
1819  td->td_lend_user_pri = prio;
1820  td->td_user_pri = min(prio, td->td_base_user_pri);
1821  if (td->td_priority > td->td_user_pri)
1822  sched_prio(td, td->td_user_pri);
1823  else if (td->td_priority != td->td_user_pri)
1824  td->td_flags |= TDF_NEEDRESCHED;
1825 }
1826 
1827 /*
1828  * Handle migration from sched_switch(). This happens only for
1829  * cpu binding.
1830  */
1831 static struct mtx *
1832 sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags)
1833 {
1834  struct tdq *tdn;
1835 
1836  tdn = TDQ_CPU(td_get_sched(td)->ts_cpu);
1837 #ifdef SMP
1838  tdq_load_rem(tdq, td);
1839  /*
1840  * Do the lock dance required to avoid LOR. We grab an extra
1841  * spinlock nesting to prevent preemption while we're
1842  * not holding either run-queue lock.
1843  */
1844  spinlock_enter();
1845  thread_lock_block(td); /* This releases the lock on tdq. */
1846 
1847  /*
1848  * Acquire both run-queue locks before placing the thread on the new
1849  * run-queue to avoid deadlocks created by placing a thread with a
1850  * blocked lock on the run-queue of a remote processor. The deadlock
1851  * occurs when a third processor attempts to lock the two queues in
1852  * question while the target processor is spinning with its own
1853  * run-queue lock held while waiting for the blocked lock to clear.
1854  */
1855  tdq_lock_pair(tdn, tdq);
1856  tdq_add(tdn, td, flags);
1857  tdq_notify(tdn, td);
1858  TDQ_UNLOCK(tdn);
1859  spinlock_exit();
1860 #endif
1861  return (TDQ_LOCKPTR(tdn));
1862 }
1863 
1864 /*
1865  * Variadic version of thread_lock_unblock() that does not assume td_lock
1866  * is blocked.
1867  */
1868 static inline void
1869 thread_unblock_switch(struct thread *td, struct mtx *mtx)
1870 {
1871  atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock,
1872  (uintptr_t)mtx);
1873 }
1874 
1875 /*
1876  * Switch threads. This function has to handle threads coming in while
1877  * blocked for some reason, running, or idle. It also must deal with
1878  * migrating a thread from one queue to another as running threads may
1879  * be assigned elsewhere via binding.
1880  */
1881 void
1882 sched_switch(struct thread *td, struct thread *newtd, int flags)
1883 {
1884  struct tdq *tdq;
1885  struct td_sched *ts;
1886  struct mtx *mtx;
1887  int srqflag;
1888  int cpuid, preempted;
1889 
1890  THREAD_LOCK_ASSERT(td, MA_OWNED);
1891  KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument"));
1892 
1893  cpuid = PCPU_GET(cpuid);
1894  tdq = TDQ_CPU(cpuid);
1895  ts = td_get_sched(td);
1896  mtx = td->td_lock;
1897  sched_pctcpu_update(ts, 1);
1898  ts->ts_rltick = ticks;
1899  td->td_lastcpu = td->td_oncpu;
1900  td->td_oncpu = NOCPU;
1901  preempted = !((td->td_flags & TDF_SLICEEND) ||
1902  (flags & SWT_RELINQUISH));
1903  td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND);
1904  td->td_owepreempt = 0;
1905  if (!TD_IS_IDLETHREAD(td))
1906  tdq->tdq_switchcnt++;
1907  /*
1908  * The lock pointer in an idle thread should never change. Reset it
1909  * to CAN_RUN as well.
1910  */
1911  if (TD_IS_IDLETHREAD(td)) {
1912  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1913  TD_SET_CAN_RUN(td);
1914  } else if (TD_IS_RUNNING(td)) {
1915  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1916  srqflag = preempted ?
1917  SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
1918  SRQ_OURSELF|SRQ_YIELDING;
1919 #ifdef SMP
1920  if (THREAD_CAN_MIGRATE(td) && !THREAD_CAN_SCHED(td, ts->ts_cpu))
1921  ts->ts_cpu = sched_pickcpu(td, 0);
1922 #endif
1923  if (ts->ts_cpu == cpuid)
1924  tdq_runq_add(tdq, td, srqflag);
1925  else {
1926  KASSERT(THREAD_CAN_MIGRATE(td) ||
1927  (ts->ts_flags & TSF_BOUND) != 0,
1928  ("Thread %p shouldn't migrate", td));
1929  mtx = sched_switch_migrate(tdq, td, srqflag);
1930  }
1931  } else {
1932  /* This thread must be going to sleep. */
1933  TDQ_LOCK(tdq);
1934  mtx = thread_lock_block(td);
1935  tdq_load_rem(tdq, td);
1936  }
1937  /*
1938  * We enter here with the thread blocked and assigned to the
1939  * appropriate cpu run-queue or sleep-queue and with the current
1940  * thread-queue locked.
1941  */
1942  TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
1943  newtd = choosethread();
1944  /*
1945  * Call the MD code to switch contexts if necessary.
1946  */
1947  if (td != newtd) {
1948 #ifdef HWPMC_HOOKS
1949  if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1950  PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
1951 #endif
1952  SDT_PROBE2(sched, , , off__cpu, newtd, newtd->td_proc);
1953  lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
1954  TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
1955  sched_pctcpu_update(td_get_sched(newtd), 0);
1956 
1957 #ifdef KDTRACE_HOOKS
1958  /*
1959  * If DTrace has set the active vtime enum to anything
1960  * other than INACTIVE (0), then it should have set the
1961  * function to call.
1962  */
1963  if (dtrace_vtime_active)
1964  (*dtrace_vtime_switch_func)(newtd);
1965 #endif
1966 
1967  cpu_switch(td, newtd, mtx);
1968  /*
1969  * We may return from cpu_switch on a different cpu. However,
1970  * we always return with td_lock pointing to the current cpu's
1971  * run queue lock.
1972  */
1973  cpuid = PCPU_GET(cpuid);
1974  tdq = TDQ_CPU(cpuid);
1975  lock_profile_obtain_lock_success(
1976  &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
1977 
1978  SDT_PROBE0(sched, , , on__cpu);
1979 #ifdef HWPMC_HOOKS
1980  if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1981  PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
1982 #endif
1983  } else {
1984  thread_unblock_switch(td, mtx);
1985  SDT_PROBE0(sched, , , remain__cpu);
1986  }
1987  /*
1988  * Assert that all went well and return.
1989  */
1990  TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED);
1991  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1992  td->td_oncpu = cpuid;
1993 }
1994 
1995 /*
1996  * Adjust thread priorities as a result of a nice request.
1997  */
1998 void
1999 sched_nice(struct proc *p, int nice)
2000 {
2001  struct thread *td;
2002 
2003  PROC_LOCK_ASSERT(p, MA_OWNED);
2004 
2005  p->p_nice = nice;
2006  FOREACH_THREAD_IN_PROC(p, td) {
2007  thread_lock(td);
2008  sched_priority(td);
2009  sched_prio(td, td->td_base_user_pri);
2010  thread_unlock(td);
2011  }
2012 }
2013 
2014 /*
2015  * Record the sleep time for the interactivity scorer.
2016  */
2017 void
2018 sched_sleep(struct thread *td, int prio)
2019 {
2020 
2021  THREAD_LOCK_ASSERT(td, MA_OWNED);
2022 
2023  td->td_slptick = ticks;
2024  if (TD_IS_SUSPENDED(td) || prio >= PSOCK)
2025  td->td_flags |= TDF_CANSWAP;
2026  if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
2027  return;
2028  if (static_boost == 1 && prio)
2029  sched_prio(td, prio);
2030  else if (static_boost && td->td_priority > static_boost)
2031  sched_prio(td, static_boost);
2032 }
2033 
2034 /*
2035  * Schedule a thread to resume execution and record how long it voluntarily
2036  * slept. We also update the pctcpu, interactivity, and priority.
2037  */
2038 void
2039 sched_wakeup(struct thread *td)
2040 {
2041  struct td_sched *ts;
2042  int slptick;
2043 
2044  THREAD_LOCK_ASSERT(td, MA_OWNED);
2045  ts = td_get_sched(td);
2046  td->td_flags &= ~TDF_CANSWAP;
2047  /*
2048  * If we slept for more than a tick update our interactivity and
2049  * priority.
2050  */
2051  slptick = td->td_slptick;
2052  td->td_slptick = 0;
2053  if (slptick && slptick != ticks) {
2054  ts->ts_slptime += (ticks - slptick) << SCHED_TICK_SHIFT;
2056  sched_pctcpu_update(ts, 0);
2057  }
2058  /*
2059  * Reset the slice value since we slept and advanced the round-robin.
2060  */
2061  ts->ts_slice = 0;
2062  sched_add(td, SRQ_BORING);
2063 }
2064 
2065 /*
2066  * Penalize the parent for creating a new child and initialize the child's
2067  * priority.
2068  */
2069 void
2070 sched_fork(struct thread *td, struct thread *child)
2071 {
2072  THREAD_LOCK_ASSERT(td, MA_OWNED);
2073  sched_pctcpu_update(td_get_sched(td), 1);
2074  sched_fork_thread(td, child);
2075  /*
2076  * Penalize the parent and child for forking.
2077  */
2078  sched_interact_fork(child);
2079  sched_priority(child);
2080  td_get_sched(td)->ts_runtime += tickincr;
2082  sched_priority(td);
2083 }
2084 
2085 /*
2086  * Fork a new thread, may be within the same process.
2087  */
2088 void
2089 sched_fork_thread(struct thread *td, struct thread *child)
2090 {
2091  struct td_sched *ts;
2092  struct td_sched *ts2;
2093  struct tdq *tdq;
2094 
2095  tdq = TDQ_SELF();
2096  THREAD_LOCK_ASSERT(td, MA_OWNED);
2097  /*
2098  * Initialize child.
2099  */
2100  ts = td_get_sched(td);
2101  ts2 = td_get_sched(child);
2102  child->td_oncpu = NOCPU;
2103  child->td_lastcpu = NOCPU;
2104  child->td_lock = TDQ_LOCKPTR(tdq);
2105  child->td_cpuset = cpuset_ref(td->td_cpuset);
2106  ts2->ts_cpu = ts->ts_cpu;
2107  ts2->ts_flags = 0;
2108  /*
2109  * Grab our parents cpu estimation information.
2110  */
2111  ts2->ts_ticks = ts->ts_ticks;
2112  ts2->ts_ltick = ts->ts_ltick;
2113  ts2->ts_ftick = ts->ts_ftick;
2114  /*
2115  * Do not inherit any borrowed priority from the parent.
2116  */
2117  child->td_priority = child->td_base_pri;
2118  /*
2119  * And update interactivity score.
2120  */
2121  ts2->ts_slptime = ts->ts_slptime;
2122  ts2->ts_runtime = ts->ts_runtime;
2123  /* Attempt to quickly learn interactivity. */
2124  ts2->ts_slice = tdq_slice(tdq) - sched_slice_min;
2125 #ifdef KTR
2126  bzero(ts2->ts_name, sizeof(ts2->ts_name));
2127 #endif
2128 }
2129 
2130 /*
2131  * Adjust the priority class of a thread.
2132  */
2133 void
2134 sched_class(struct thread *td, int class)
2135 {
2136 
2137  THREAD_LOCK_ASSERT(td, MA_OWNED);
2138  if (td->td_pri_class == class)
2139  return;
2140  td->td_pri_class = class;
2141 }
2142 
2143 /*
2144  * Return some of the child's priority and interactivity to the parent.
2145  */
2146 void
2147 sched_exit(struct proc *p, struct thread *child)
2148 {
2149  struct thread *td;
2150 
2151  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit",
2152  "prio:%d", child->td_priority);
2153  PROC_LOCK_ASSERT(p, MA_OWNED);
2154  td = FIRST_THREAD_IN_PROC(p);
2155  sched_exit_thread(td, child);
2156 }
2157 
2158 /*
2159  * Penalize another thread for the time spent on this one. This helps to
2160  * worsen the priority and interactivity of processes which schedule batch
2161  * jobs such as make. This has little effect on the make process itself but
2162  * causes new processes spawned by it to receive worse scores immediately.
2163  */
2164 void
2165 sched_exit_thread(struct thread *td, struct thread *child)
2166 {
2167 
2168  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit",
2169  "prio:%d", child->td_priority);
2170  /*
2171  * Give the child's runtime to the parent without returning the
2172  * sleep time as a penalty to the parent. This causes shells that
2173  * launch expensive things to mark their children as expensive.
2174  */
2175  thread_lock(td);
2176  td_get_sched(td)->ts_runtime += td_get_sched(child)->ts_runtime;
2178  sched_priority(td);
2179  thread_unlock(td);
2180 }
2181 
2182 void
2183 sched_preempt(struct thread *td)
2184 {
2185  struct tdq *tdq;
2186 
2187  SDT_PROBE2(sched, , , surrender, td, td->td_proc);
2188 
2189  thread_lock(td);
2190  tdq = TDQ_SELF();
2191  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2192  tdq->tdq_ipipending = 0;
2193  if (td->td_priority > tdq->tdq_lowpri) {
2194  int flags;
2195 
2196  flags = SW_INVOL | SW_PREEMPT;
2197  if (td->td_critnest > 1)
2198  td->td_owepreempt = 1;
2199  else if (TD_IS_IDLETHREAD(td))
2200  mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL);
2201  else
2202  mi_switch(flags | SWT_REMOTEPREEMPT, NULL);
2203  }
2204  thread_unlock(td);
2205 }
2206 
2207 /*
2208  * Fix priorities on return to user-space. Priorities may be elevated due
2209  * to static priorities in msleep() or similar.
2210  */
2211 void
2212 sched_userret(struct thread *td)
2213 {
2214  /*
2215  * XXX we cheat slightly on the locking here to avoid locking in
2216  * the usual case. Setting td_priority here is essentially an
2217  * incomplete workaround for not setting it properly elsewhere.
2218  * Now that some interrupt handlers are threads, not setting it
2219  * properly elsewhere can clobber it in the window between setting
2220  * it here and returning to user mode, so don't waste time setting
2221  * it perfectly here.
2222  */
2223  KASSERT((td->td_flags & TDF_BORROWING) == 0,
2224  ("thread with borrowed priority returning to userland"));
2225  if (td->td_priority != td->td_user_pri) {
2226  thread_lock(td);
2227  td->td_priority = td->td_user_pri;
2228  td->td_base_pri = td->td_user_pri;
2229  tdq_setlowpri(TDQ_SELF(), td);
2230  thread_unlock(td);
2231  }
2232 }
2233 
2234 /*
2235  * Handle a stathz tick. This is really only relevant for timeshare
2236  * threads.
2237  */
2238 void
2239 sched_clock(struct thread *td)
2240 {
2241  struct tdq *tdq;
2242  struct td_sched *ts;
2243 
2244  THREAD_LOCK_ASSERT(td, MA_OWNED);
2245  tdq = TDQ_SELF();
2246 #ifdef SMP
2247  /*
2248  * We run the long term load balancer infrequently on the first cpu.
2249  */
2250  if (balance_tdq == tdq) {
2251  if (balance_ticks && --balance_ticks == 0)
2252  sched_balance();
2253  }
2254 #endif
2255  /*
2256  * Save the old switch count so we have a record of the last ticks
2257  * activity. Initialize the new switch count based on our load.
2258  * If there is some activity seed it to reflect that.
2259  */
2260  tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt;
2261  tdq->tdq_switchcnt = tdq->tdq_load;
2262  /*
2263  * Advance the insert index once for each tick to ensure that all
2264  * threads get a chance to run.
2265  */
2266  if (tdq->tdq_idx == tdq->tdq_ridx) {
2267  tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS;
2268  if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx]))
2269  tdq->tdq_ridx = tdq->tdq_idx;
2270  }
2271  ts = td_get_sched(td);
2272  sched_pctcpu_update(ts, 1);
2273  if (td->td_pri_class & PRI_FIFO_BIT)
2274  return;
2275  if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) {
2276  /*
2277  * We used a tick; charge it to the thread so
2278  * that we can compute our interactivity.
2279  */
2280  td_get_sched(td)->ts_runtime += tickincr;
2282  sched_priority(td);
2283  }
2284 
2285  /*
2286  * Force a context switch if the current thread has used up a full
2287  * time slice (default is 100ms).
2288  */
2289  if (!TD_IS_IDLETHREAD(td) && ++ts->ts_slice >= tdq_slice(tdq)) {
2290  ts->ts_slice = 0;
2291  td->td_flags |= TDF_NEEDRESCHED | TDF_SLICEEND;
2292  }
2293 }
2294 
2295 u_int
2296 sched_estcpu(struct thread *td __unused)
2297 {
2298 
2299  return (0);
2300 }
2301 
2302 /*
2303  * Return whether the current CPU has runnable tasks. Used for in-kernel
2304  * cooperative idle threads.
2305  */
2306 int
2308 {
2309  struct tdq *tdq;
2310  int load;
2311 
2312  load = 1;
2313 
2314  tdq = TDQ_SELF();
2315  if ((curthread->td_flags & TDF_IDLETD) != 0) {
2316  if (tdq->tdq_load > 0)
2317  goto out;
2318  } else
2319  if (tdq->tdq_load - 1 > 0)
2320  goto out;
2321  load = 0;
2322 out:
2323  return (load);
2324 }
2325 
2326 /*
2327  * Choose the highest priority thread to run. The thread is removed from
2328  * the run-queue while running however the load remains. For SMP we set
2329  * the tdq in the global idle bitmask if it idles here.
2330  */
2331 struct thread *
2333 {
2334  struct thread *td;
2335  struct tdq *tdq;
2336 
2337  tdq = TDQ_SELF();
2338  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2339  td = tdq_choose(tdq);
2340  if (td) {
2341  tdq_runq_rem(tdq, td);
2342  tdq->tdq_lowpri = td->td_priority;
2343  return (td);
2344  }
2345  tdq->tdq_lowpri = PRI_MAX_IDLE;
2346  return (PCPU_GET(idlethread));
2347 }
2348 
2349 /*
2350  * Set owepreempt if necessary. Preemption never happens directly in ULE,
2351  * we always request it once we exit a critical section.
2352  */
2353 static inline void
2354 sched_setpreempt(struct thread *td)
2355 {
2356  struct thread *ctd;
2357  int cpri;
2358  int pri;
2359 
2360  THREAD_LOCK_ASSERT(curthread, MA_OWNED);
2361 
2362  ctd = curthread;
2363  pri = td->td_priority;
2364  cpri = ctd->td_priority;
2365  if (pri < cpri)
2366  ctd->td_flags |= TDF_NEEDRESCHED;
2367  if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd))
2368  return;
2369  if (!sched_shouldpreempt(pri, cpri, 0))
2370  return;
2371  ctd->td_owepreempt = 1;
2372 }
2373 
2374 /*
2375  * Add a thread to a thread queue. Select the appropriate runq and add the
2376  * thread to it. This is the internal function called when the tdq is
2377  * predetermined.
2378  */
2379 void
2380 tdq_add(struct tdq *tdq, struct thread *td, int flags)
2381 {
2382 
2383  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2384  KASSERT((td->td_inhibitors == 0),
2385  ("sched_add: trying to run inhibited thread"));
2386  KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
2387  ("sched_add: bad thread state"));
2388  KASSERT(td->td_flags & TDF_INMEM,
2389  ("sched_add: thread swapped out"));
2390 
2391  if (td->td_priority < tdq->tdq_lowpri)
2392  tdq->tdq_lowpri = td->td_priority;
2393  tdq_runq_add(tdq, td, flags);
2394  tdq_load_add(tdq, td);
2395 }
2396 
2397 /*
2398  * Select the target thread queue and add a thread to it. Request
2399  * preemption or IPI a remote processor if required.
2400  */
2401 void
2402 sched_add(struct thread *td, int flags)
2403 {
2404  struct tdq *tdq;
2405 #ifdef SMP
2406  int cpu;
2407 #endif
2408 
2409  KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
2410  "prio:%d", td->td_priority, KTR_ATTR_LINKED,
2411  sched_tdname(curthread));
2412  KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
2413  KTR_ATTR_LINKED, sched_tdname(td));
2414  SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL,
2415  flags & SRQ_PREEMPTED);
2416  THREAD_LOCK_ASSERT(td, MA_OWNED);
2417  /*
2418  * Recalculate the priority before we select the target cpu or
2419  * run-queue.
2420  */
2421  if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
2422  sched_priority(td);
2423 #ifdef SMP
2424  /*
2425  * Pick the destination cpu and if it isn't ours transfer to the
2426  * target cpu.
2427  */
2428  cpu = sched_pickcpu(td, flags);
2429  tdq = sched_setcpu(td, cpu, flags);
2430  tdq_add(tdq, td, flags);
2431  if (cpu != PCPU_GET(cpuid)) {
2432  tdq_notify(tdq, td);
2433  return;
2434  }
2435 #else
2436  tdq = TDQ_SELF();
2437  TDQ_LOCK(tdq);
2438  /*
2439  * Now that the thread is moving to the run-queue, set the lock
2440  * to the scheduler's lock.
2441  */
2442  thread_lock_set(td, TDQ_LOCKPTR(tdq));
2443  tdq_add(tdq, td, flags);
2444 #endif
2445  if (!(flags & SRQ_YIELDING))
2446  sched_setpreempt(td);
2447 }
2448 
2449 /*
2450  * Remove a thread from a run-queue without running it. This is used
2451  * when we're stealing a thread from a remote queue. Otherwise all threads
2452  * exit by calling sched_exit_thread() and sched_throw() themselves.
2453  */
2454 void
2455 sched_rem(struct thread *td)
2456 {
2457  struct tdq *tdq;
2458 
2459  KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem",
2460  "prio:%d", td->td_priority);
2461  SDT_PROBE3(sched, , , dequeue, td, td->td_proc, NULL);
2462  tdq = TDQ_CPU(td_get_sched(td)->ts_cpu);
2463  TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2464  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2465  KASSERT(TD_ON_RUNQ(td),
2466  ("sched_rem: thread not on run queue"));
2467  tdq_runq_rem(tdq, td);
2468  tdq_load_rem(tdq, td);
2469  TD_SET_CAN_RUN(td);
2470  if (td->td_priority == tdq->tdq_lowpri)
2471  tdq_setlowpri(tdq, NULL);
2472 }
2473 
2474 /*
2475  * Fetch cpu utilization information. Updates on demand.
2476  */
2477 fixpt_t
2478 sched_pctcpu(struct thread *td)
2479 {
2480  fixpt_t pctcpu;
2481  struct td_sched *ts;
2482 
2483  pctcpu = 0;
2484  ts = td_get_sched(td);
2485 
2486  THREAD_LOCK_ASSERT(td, MA_OWNED);
2487  sched_pctcpu_update(ts, TD_IS_RUNNING(td));
2488  if (ts->ts_ticks) {
2489  int rtick;
2490 
2491  /* How many rtick per second ? */
2492  rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz);
2493  pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT;
2494  }
2495 
2496  return (pctcpu);
2497 }
2498 
2499 /*
2500  * Enforce affinity settings for a thread. Called after adjustments to
2501  * cpumask.
2502  */
2503 void
2504 sched_affinity(struct thread *td)
2505 {
2506 #ifdef SMP
2507  struct td_sched *ts;
2508 
2509  THREAD_LOCK_ASSERT(td, MA_OWNED);
2510  ts = td_get_sched(td);
2511  if (THREAD_CAN_SCHED(td, ts->ts_cpu))
2512  return;
2513  if (TD_ON_RUNQ(td)) {
2514  sched_rem(td);
2515  sched_add(td, SRQ_BORING);
2516  return;
2517  }
2518  if (!TD_IS_RUNNING(td))
2519  return;
2520  /*
2521  * Force a switch before returning to userspace. If the
2522  * target thread is not running locally send an ipi to force
2523  * the issue.
2524  */
2525  td->td_flags |= TDF_NEEDRESCHED;
2526  if (td != curthread)
2527  ipi_cpu(ts->ts_cpu, IPI_PREEMPT);
2528 #endif
2529 }
2530 
2531 /*
2532  * Bind a thread to a target cpu.
2533  */
2534 void
2535 sched_bind(struct thread *td, int cpu)
2536 {
2537  struct td_sched *ts;
2538 
2539  THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED);
2540  KASSERT(td == curthread, ("sched_bind: can only bind curthread"));
2541  ts = td_get_sched(td);
2542  if (ts->ts_flags & TSF_BOUND)
2543  sched_unbind(td);
2544  KASSERT(THREAD_CAN_MIGRATE(td), ("%p must be migratable", td));
2545  ts->ts_flags |= TSF_BOUND;
2546  sched_pin();
2547  if (PCPU_GET(cpuid) == cpu)
2548  return;
2549  ts->ts_cpu = cpu;
2550  /* When we return from mi_switch we'll be on the correct cpu. */
2551  mi_switch(SW_VOL, NULL);
2552 }
2553 
2554 /*
2555  * Release a bound thread.
2556  */
2557 void
2558 sched_unbind(struct thread *td)
2559 {
2560  struct td_sched *ts;
2561 
2562  THREAD_LOCK_ASSERT(td, MA_OWNED);
2563  KASSERT(td == curthread, ("sched_unbind: can only bind curthread"));
2564  ts = td_get_sched(td);
2565  if ((ts->ts_flags & TSF_BOUND) == 0)
2566  return;
2567  ts->ts_flags &= ~TSF_BOUND;
2568  sched_unpin();
2569 }
2570 
2571 int
2572 sched_is_bound(struct thread *td)
2573 {
2574  THREAD_LOCK_ASSERT(td, MA_OWNED);
2575  return (td_get_sched(td)->ts_flags & TSF_BOUND);
2576 }
2577 
2578 /*
2579  * Basic yield call.
2580  */
2581 void
2582 sched_relinquish(struct thread *td)
2583 {
2584  thread_lock(td);
2585  mi_switch(SW_VOL | SWT_RELINQUISH, NULL);
2586  thread_unlock(td);
2587 }
2588 
2589 /*
2590  * Return the total system load.
2591  */
2592 int
2594 {
2595 #ifdef SMP
2596  int total;
2597  int i;
2598 
2599  total = 0;
2600  CPU_FOREACH(i)
2601  total += TDQ_CPU(i)->tdq_sysload;
2602  return (total);
2603 #else
2604  return (TDQ_SELF()->tdq_sysload);
2605 #endif
2606 }
2607 
2608 int
2610 {
2611  return (sizeof(struct proc));
2612 }
2613 
2614 int
2616 {
2617  return (sizeof(struct thread) + sizeof(struct td_sched));
2618 }
2619 
2620 #ifdef SMP
2621 #define TDQ_IDLESPIN(tdq) \
2622  ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0)
2623 #else
2624 #define TDQ_IDLESPIN(tdq) 1
2625 #endif
2626 
2627 /*
2628  * The actual idle process.
2629  */
2630 void
2632 {
2633  struct thread *td;
2634  struct tdq *tdq;
2635  int oldswitchcnt, switchcnt;
2636  int i;
2637 
2638  mtx_assert(&Giant, MA_NOTOWNED);
2639  td = curthread;
2640  tdq = TDQ_SELF();
2641  THREAD_NO_SLEEPING();
2642  oldswitchcnt = -1;
2643  for (;;) {
2644  if (tdq->tdq_load) {
2645  thread_lock(td);
2646  mi_switch(SW_VOL | SWT_IDLE, NULL);
2647  thread_unlock(td);
2648  }
2649  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2650 #ifdef SMP
2651  if (switchcnt != oldswitchcnt) {
2652  oldswitchcnt = switchcnt;
2653  if (tdq_idled(tdq) == 0)
2654  continue;
2655  }
2656  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2657 #else
2658  oldswitchcnt = switchcnt;
2659 #endif
2660  /*
2661  * If we're switching very frequently, spin while checking
2662  * for load rather than entering a low power state that
2663  * may require an IPI. However, don't do any busy
2664  * loops while on SMT machines as this simply steals
2665  * cycles from cores doing useful work.
2666  */
2667  if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) {
2668  for (i = 0; i < sched_idlespins; i++) {
2669  if (tdq->tdq_load)
2670  break;
2671  cpu_spinwait();
2672  }
2673  }
2674 
2675  /* If there was context switch during spin, restart it. */
2676  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2677  if (tdq->tdq_load != 0 || switchcnt != oldswitchcnt)
2678  continue;
2679 
2680  /* Run main MD idle handler. */
2681  tdq->tdq_cpu_idle = 1;
2682  /*
2683  * Make sure that tdq_cpu_idle update is globally visible
2684  * before cpu_idle() read tdq_load. The order is important
2685  * to avoid race with tdq_notify.
2686  */
2687  atomic_thread_fence_seq_cst();
2688  cpu_idle(switchcnt * 4 > sched_idlespinthresh);
2689  tdq->tdq_cpu_idle = 0;
2690 
2691  /*
2692  * Account thread-less hardware interrupts and
2693  * other wakeup reasons equal to context switches.
2694  */
2695  switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2696  if (switchcnt != oldswitchcnt)
2697  continue;
2698  tdq->tdq_switchcnt++;
2699  oldswitchcnt++;
2700  }
2701 }
2702 
2703 /*
2704  * A CPU is entering for the first time or a thread is exiting.
2705  */
2706 void
2707 sched_throw(struct thread *td)
2708 {
2709  struct thread *newtd;
2710  struct tdq *tdq;
2711 
2712  tdq = TDQ_SELF();
2713  if (td == NULL) {
2714  /* Correct spinlock nesting and acquire the correct lock. */
2715  TDQ_LOCK(tdq);
2716  spinlock_exit();
2717  PCPU_SET(switchtime, cpu_ticks());
2718  PCPU_SET(switchticks, ticks);
2719  } else {
2720  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2721  tdq_load_rem(tdq, td);
2722  lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
2723  td->td_lastcpu = td->td_oncpu;
2724  td->td_oncpu = NOCPU;
2725  }
2726  KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
2727  newtd = choosethread();
2728  TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
2729  cpu_throw(td, newtd); /* doesn't return */
2730 }
2731 
2732 /*
2733  * This is called from fork_exit(). Just acquire the correct locks and
2734  * let fork do the rest of the work.
2735  */
2736 void
2737 sched_fork_exit(struct thread *td)
2738 {
2739  struct tdq *tdq;
2740  int cpuid;
2741 
2742  /*
2743  * Finish setting up thread glue so that it begins execution in a
2744  * non-nested critical section with the scheduler lock held.
2745  */
2746  cpuid = PCPU_GET(cpuid);
2747  tdq = TDQ_CPU(cpuid);
2748  if (TD_IS_IDLETHREAD(td))
2749  td->td_lock = TDQ_LOCKPTR(tdq);
2750  MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2751  td->td_oncpu = cpuid;
2752  TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
2753  lock_profile_obtain_lock_success(
2754  &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
2755 }
2756 
2757 /*
2758  * Create on first use to catch odd startup conditons.
2759  */
2760 char *
2761 sched_tdname(struct thread *td)
2762 {
2763 #ifdef KTR
2764  struct td_sched *ts;
2765 
2766  ts = td_get_sched(td);
2767  if (ts->ts_name[0] == '\0')
2768  snprintf(ts->ts_name, sizeof(ts->ts_name),
2769  "%s tid %d", td->td_name, td->td_tid);
2770  return (ts->ts_name);
2771 #else
2772  return (td->td_name);
2773 #endif
2774 }
2775 
2776 #ifdef KTR
2777 void
2778 sched_clear_tdname(struct thread *td)
2779 {
2780  struct td_sched *ts;
2781 
2782  ts = td_get_sched(td);
2783  ts->ts_name[0] = '\0';
2784 }
2785 #endif
2786 
2787 #ifdef SMP
2788 
2789 /*
2790  * Build the CPU topology dump string. Is recursively called to collect
2791  * the topology tree.
2792  */
2793 static int
2794 sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg,
2795  int indent)
2796 {
2797  char cpusetbuf[CPUSETBUFSIZ];
2798  int i, first;
2799 
2800  sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent,
2801  "", 1 + indent / 2, cg->cg_level);
2802  sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"%s\">", indent, "",
2803  cg->cg_count, cpusetobj_strprint(cpusetbuf, &cg->cg_mask));
2804  first = TRUE;
2805  for (i = 0; i < MAXCPU; i++) {
2806  if (CPU_ISSET(i, &cg->cg_mask)) {
2807  if (!first)
2808  sbuf_printf(sb, ", ");
2809  else
2810  first = FALSE;
2811  sbuf_printf(sb, "%d", i);
2812  }
2813  }
2814  sbuf_printf(sb, "</cpu>\n");
2815 
2816  if (cg->cg_flags != 0) {
2817  sbuf_printf(sb, "%*s <flags>", indent, "");
2818  if ((cg->cg_flags & CG_FLAG_HTT) != 0)
2819  sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>");
2820  if ((cg->cg_flags & CG_FLAG_THREAD) != 0)
2821  sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>");
2822  if ((cg->cg_flags & CG_FLAG_SMT) != 0)
2823  sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>");
2824  sbuf_printf(sb, "</flags>\n");
2825  }
2826 
2827  if (cg->cg_children > 0) {
2828  sbuf_printf(sb, "%*s <children>\n", indent, "");
2829  for (i = 0; i < cg->cg_children; i++)
2830  sysctl_kern_sched_topology_spec_internal(sb,
2831  &cg->cg_child[i], indent+2);
2832  sbuf_printf(sb, "%*s </children>\n", indent, "");
2833  }
2834  sbuf_printf(sb, "%*s</group>\n", indent, "");
2835  return (0);
2836 }
2837 
2838 /*
2839  * Sysctl handler for retrieving topology dump. It's a wrapper for
2840  * the recursive sysctl_kern_smp_topology_spec_internal().
2841  */
2842 static int
2843 sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS)
2844 {
2845  struct sbuf *topo;
2846  int err;
2847 
2848  KASSERT(cpu_top != NULL, ("cpu_top isn't initialized"));
2849 
2850  topo = sbuf_new_for_sysctl(NULL, NULL, 512, req);
2851  if (topo == NULL)
2852  return (ENOMEM);
2853 
2854  sbuf_printf(topo, "<groups>\n");
2855  err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1);
2856  sbuf_printf(topo, "</groups>\n");
2857 
2858  if (err == 0) {
2859  err = sbuf_finish(topo);
2860  }
2861  sbuf_delete(topo);
2862  return (err);
2863 }
2864 
2865 #endif
2866 
2867 static int
2868 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
2869 {
2870  int error, new_val, period;
2871 
2872  period = 1000000 / realstathz;
2873  new_val = period * sched_slice;
2874  error = sysctl_handle_int(oidp, &new_val, 0, req);
2875  if (error != 0 || req->newptr == NULL)
2876  return (error);
2877  if (new_val <= 0)
2878  return (EINVAL);
2879  sched_slice = imax(1, (new_val + period / 2) / period);
2880  sched_slice_min = sched_slice / SCHED_SLICE_MIN_DIVISOR;
2881  hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
2882  realstathz);
2883  return (0);
2884 }
2885 
2886 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler");
2887 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0,
2888  "Scheduler name");
2889 SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW,
2890  NULL, 0, sysctl_kern_quantum, "I",
2891  "Quantum for timeshare threads in microseconds");
2892 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
2893  "Quantum for timeshare threads in stathz ticks");
2894 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0,
2895  "Interactivity score threshold");
2896 SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW,
2897  &preempt_thresh, 0,
2898  "Maximal (lowest) priority for preemption");
2899 SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 0,
2900  "Assign static kernel priorities to sleeping threads");
2901 SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 0,
2902  "Number of times idle thread will spin waiting for new work");
2903 SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW,
2904  &sched_idlespinthresh, 0,
2905  "Threshold before we will permit idle thread spinning");
2906 #ifdef SMP
2907 SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0,
2908  "Number of hz ticks to keep thread affinity for");
2909 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0,
2910  "Enables the long-term load balancer");
2911 SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW,
2912  &balance_interval, 0,
2913  "Average period in stathz ticks to run the long-term balancer");
2914 SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0,
2915  "Attempts to steal work from other cores before idling");
2916 SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0,
2917  "Minimum load on remote CPU before we'll steal");
2918 SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING |
2919  CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A",
2920  "XML dump of detected CPU topology");
2921 #endif
2922 
2923 /* ps compat. All cpu percentages from ULE are weighted. */
2924 static int ccpu = 0;
2925 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
static struct tdq tdq_cpu
Definition: sched_ule.c:288
volatile int smp_started
Definition: subr_smp.c:75
u_int ts_runtime
Definition: sched_ule.c:97
static void sched_initticks(void *dummy)
Definition: sched_ule.c:1414
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Definition: sched_ule.c:100
#define TS_NAME_LEN
Definition: sched_ule.c:82
#define TDQ_LOCK_ASSERT(t, type)
Definition: sched_ule.c:295
static int sched_shouldpreempt(int, int, int)
Definition: sched_ule.c:418
device_t child
Definition: msi_if.m:40
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Definition: sched_ule.c:1647
SDT_PROBE_DEFINE2(sched,,, load__change,"int","int")
#define SCHED_TICK_SHIFT
Definition: sched_ule.c:146
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Definition: sched_ule.c:292
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Definition: kern_switch.c:338
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Definition: sched_ule.c:1628
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Definition: sched_ule.c:233
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Definition: sched_ule.c:239
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Definition: sched_ule.c:1739
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Definition: sched_ule.c:2332
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Definition: sched_ule.c:2134
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Definition: subr_prf.c:520
struct timespec * ts
Definition: clock_if.m:39
#define TDF_SLICEEND
Definition: sched_ule.c:197
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Definition: sched_ule.c:92
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Definition: sched_ule.c:2165
_Static_assert(sizeof(struct thread)+sizeof(struct td_sched)<=sizeof(struct thread0_storage),"increase struct thread0_storage.t0st_sched size")
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Definition: sched_ule.c:2089
int bootverbose
Definition: init_main.c:116
void *** start
Definition: linker_if.m:86
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Definition: subr_smp.c:76
u_int ts_slptime
Definition: sched_ule.c:96
#define SCHED_PRI_MIN
Definition: sched_ule.c:164
#define SCHED_PRI_RANGE
Definition: sched_ule.c:166
static void sched_setup(void *dummy)
Definition: sched_ule.c:1390
#define THREAD_CAN_SCHED(td, cpu)
Definition: sched_ule.c:110
short tdq_oldswitchcnt
Definition: sched_ule.c:236
static int sched_interact_score(struct thread *)
Definition: sched_ule.c:1472
static __inline void tdq_runq_rem(struct tdq *, struct thread *)
Definition: sched_ule.c:507
void sched_user_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1805
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:2868
short tdq_oldswitchcnt
Definition: sched_ule.c:243
void panic(const char *fmt,...)
static void sched_interact_update(struct thread *)
Definition: sched_ule.c:1564
struct thread * choosethread(void)
Definition: kern_switch.c:154
struct mtx_padalign tdq_lock
Definition: sched_ule.c:236
u_char tdq_ipipending
Definition: sched_ule.c:245
struct tdq __aligned(64)
#define PRI_MIN_BATCH
Definition: sched_ule.c:130
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:2761
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Definition: subr_pcpu.c:278
static int ccpu
Definition: sched_ule.c:2924
int ts_flags
Definition: sched_4bsd.c:99
int ts_ftick
Definition: sched_ule.c:99
short tdq_switchcnt
Definition: sched_ule.c:235
static void tdq_setup(struct tdq *)
Definition: sched_ule.c:1347
const char * name
Definition: kern_fail.c:143
int ts_slptime
Definition: sched_4bsd.c:97
char tdq_name[TDQ_NAME_LEN]
Definition: sched_ule.c:244
void mi_switch(int flags, struct thread *newtd)
Definition: kern_synch.c:396
void sched_sleep(struct thread *td, int prio)
Definition: sched_ule.c:2018
#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)
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Definition: sched_ule.c:551
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Definition: sched_ule.c:243
SDT_PROBE_DEFINE(sched,,, on__cpu)
u_char tdq_ridx
Definition: sched_ule.c:247
int ts_ltick
Definition: sched_ule.c:98
volatile int tdq_load
Definition: sched_ule.c:231
struct thread * runq_choose_from(struct runq *rq, u_char idx)
Definition: kern_switch.c:462
static int sched_idlespins
Definition: sched_ule.c:222
#define PRI_MAX_INTERACT
Definition: sched_ule.c:129
int ts_slice
Definition: sched_4bsd.c:98
char tdq_name[TDQ_NAME_LEN]
Definition: sched_ule.c:251
#define SCHED_INTERACT_HALF
Definition: sched_ule.c:187
struct runq tdq_realtime
Definition: sched_ule.c:241
#define TDQ_IDLESPIN(tdq)
Definition: sched_ule.c:2624
static int sched_idlespinthresh
Definition: sched_ule.c:223
#define TDQ_ID(x)
Definition: sched_ule.c:290
static struct runq runq
Definition: sched_4bsd.c:161
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:194
static int sched_slice_min
Definition: sched_ule.c:211
static void tdq_setlowpri(struct tdq *tdq, struct thread *ctd)
Definition: sched_ule.c:595
void sched_throw(struct thread *td)
Definition: sched_ule.c:2707
struct thread * runq_choose(struct runq *rq)
Definition: kern_switch.c:442
void thread_lock_set(struct thread *td, struct mtx *new)
Definition: kern_mutex.c:857
void sched_fork_exit(struct thread *td)
Definition: sched_ule.c:2737
struct cpuset * cpuset_ref(struct cpuset *set)
Definition: kern_cpuset.c:126
void sched_relinquish(struct thread *td)
Definition: sched_ule.c:2582
static int dummy
void tdq_print(int cpu)
Definition: sched_ule.c:393
u_int sched_estcpu(struct thread *td __unused)
Definition: sched_ule.c:2296
Definition: sched_ule.c:230
struct mtx Giant
Definition: kern_mutex.c:207
void sched_wakeup(struct thread *td)
Definition: sched_ule.c:2039
struct runq * ts_runq
Definition: sched_4bsd.c:100
int sched_sizeof_thread(void)
Definition: sched_ule.c:2615
void sched_switch(struct thread *td, struct thread *newtd, int flags)
Definition: sched_ule.c:1882
void sched_rem(struct thread *td)
Definition: sched_ule.c:2455
u_long flags
#define SCHED_TICK_SECS
Definition: sched_ule.c:143
struct cpu_group * tdq_cg
Definition: sched_ule.c:237
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:671
#define SCHED_SLP_RUN_FORK
Definition: sched_ule.c:185
void sched_lend_user_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1815
DPCPU_DEFINE(sbintime_t, hardclocktime)
#define PRI_MIN_INTERACT
Definition: sched_ule.c:128
static struct thread * tdq_choose(struct tdq *)
Definition: sched_ule.c:1317
static int tickincr
Definition: sched_ule.c:208
int tdq_transferable
Definition: sched_ule.c:234
int sched_is_bound(struct thread *td)
Definition: sched_ule.c:2572
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:1832
int sysctl_handle_int(SYSCTL_HANDLER_ARGS)
Definition: kern_sysctl.c:1322
#define TDQ_SELF()
Definition: sched_ule.c:291
#define TDQ_LOADNAME_LEN
Definition: sched_ule.c:84
__FBSDID("$FreeBSD: head/sys/kern/sched_ule.c 301456 2016-06-05 17:04:03Z kib $")
#define SCHED_TICK_MAX
Definition: sched_ule.c:145
struct runq tdq_timeshare
Definition: sched_ule.c:249
void sched_clock(struct thread *td)
Definition: sched_ule.c:2239
static void runq_print(struct runq *rq)
Definition: sched_ule.c:365
static void sched_thread_priority(struct thread *, u_char)
Definition: sched_ule.c:1684
void runq_remove(struct runq *rq, struct thread *td)
Definition: kern_switch.c:487
struct runq tdq_realtime
Definition: sched_ule.c:248
static __inline void tdq_runq_add(struct tdq *, struct thread *, int)
Definition: sched_ule.c:456
#define SCHED_PRI_NICE(nice)
Definition: sched_ule.c:170
void sched_affinity(struct thread *td)
Definition: sched_ule.c:2504
int printf(const char *fmt,...)
Definition: subr_prf.c:384
void sched_exit(struct proc *p, struct thread *child)
Definition: sched_ule.c:2147
struct runq tdq_idle
Definition: sched_ule.c:250
#define SCHED_PRI_TICKS(ts)
Definition: sched_ule.c:167
void sbuf_delete(struct sbuf *s)
Definition: subr_sbuf.c:798
#define TDQ_LOCK_FLAGS(t, f)
Definition: sched_ule.c:297
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:2631
void sched_unlend_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1755
int tdq_sysload
Definition: sched_ule.c:240
#define TSF_BOUND
Definition: sched_ule.c:106
struct cpu_group * tdq_cg
Definition: sched_ule.c:230
struct runq tdq_timeshare
Definition: sched_ule.c:242
#define SCHED_TICK_HZ(ts)
Definition: sched_ule.c:147
static void thread_unblock_switch(struct thread *td, struct mtx *mtx)
Definition: sched_ule.c:1869
int sbuf_finish(struct sbuf *s)
Definition: subr_sbuf.c:733
void sched_preempt(struct thread *td)
Definition: sched_ule.c:2183
static int realstathz
Definition: sched_ule.c:209
volatile int tdq_load
Definition: sched_ule.c:238
#define TDQ_LOCK(t)
Definition: sched_ule.c:296
#define SCHED_SLICE_DEFAULT_DIVISOR
Definition: sched_ule.c:193
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:298
volatile int ticks
Definition: kern_clock.c:380
int sched_load(void)
Definition: sched_ule.c:2593
int hogticks
Definition: kern_synch.c:80
SDT_PROVIDER_DEFINE(sched)
static int sched_interact
Definition: sched_ule.c:207
static int tdq_slice(struct tdq *tdq)
Definition: sched_ule.c:573
static void sched_interact_fork(struct thread *)
Definition: sched_ule.c:1609
int stathz
Definition: kern_clock.c:377
static void sched_priority(struct thread *)
Definition: sched_ule.c:1512
void sched_nice(struct proc *p, int nice)
Definition: sched_ule.c:1999
#define SCHED_SLP_RUN_MAX
Definition: sched_ule.c:184
static void sched_setpreempt(struct thread *td)
Definition: sched_ule.c:2354
int tdq_transferable
Definition: sched_ule.c:241
static int sched_slice
Definition: sched_ule.c:210
char * cpusetobj_strprint(char *buf, const cpuset_t *set)
Definition: kern_cpuset.c:634
void sched_userret(struct thread *td)
Definition: sched_ule.c:2212
#define TDQ_LOCKPTR(t)
Definition: sched_ule.c:299
void sched_fork(struct thread *td, struct thread *child)
Definition: sched_ule.c:2070
#define SCHED_INTERACT_THRESH
Definition: sched_ule.c:188
#define PRI_MAX_BATCH
Definition: sched_ule.c:131
static void tdq_add(struct tdq *, struct thread *, int)
Definition: sched_ule.c:2380
struct mtx * thread_lock_block(struct thread *td)
Definition: kern_mutex.c:836
u_char tdq_idx
Definition: sched_ule.c:246
#define SCHED_TICK_TARG
Definition: sched_ule.c:144
int sched_runnable(void)
Definition: sched_ule.c:2307
struct mtx_padalign tdq_lock
Definition: sched_ule.c:229
void sched_unbind(struct thread *td)
Definition: sched_ule.c:2558
static int preempt_thresh
Definition: sched_ule.c:219
#define PRI_BATCH_RANGE
Definition: sched_ule.c:126
#define THREAD_CAN_MIGRATE(td)
Definition: sched_ule.c:109
volatile int tdq_cpu_idle
Definition: sched_ule.c:232
void sched_prio(struct thread *td, u_char prio)
Definition: sched_ule.c:1775
SDT_PROBE_DEFINE3(sched,,, change__pri,"struct thread *","struct proc *","uint8_t")
void sched_add(struct thread *td, int flags)
Definition: sched_ule.c:2402
short tdq_switchcnt
Definition: sched_ule.c:242
u_char tdq_lowpri
Definition: sched_ule.c:237
u_char tdq_lowpri
Definition: sched_ule.c:244
static void tdq_load_add(struct tdq *, struct thread *)
Definition: sched_ule.c:533
cpu_tick_f * cpu_ticks
Definition: kern_tc.c:2110
void thread_lock_unblock(struct thread *td, struct mtx *new)
Definition: kern_mutex.c:849
#define TDQ_NAME_LEN
Definition: sched_ule.c:83
static int static_boost
Definition: sched_ule.c:221
void sched_bind(struct thread *td, int cpu)
Definition: sched_ule.c:2535
struct sbuf * sbuf_new_for_sysctl(struct sbuf *s, char *buf, int length, struct sysctl_req *req)
Definition: kern_sysctl.c:2020
int hz
Definition: subr_param.c:84
fixpt_t sched_pctcpu(struct thread *td)
Definition: sched_ule.c:2478
int sched_sizeof_proc(void)
Definition: sched_ule.c:2609
static void sched_pctcpu_update(struct td_sched *, int)
Definition: sched_ule.c:1661