FreeBSD/Linux Kernel Cross Reference
sys/kern/sched_ule.c
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: releng/9.0/sys/kern/sched_ule.c 225199 2011-08-26 18:00:07Z delphij $");
40
41 #include "opt_hwpmc_hooks.h"
42 #include "opt_kdtrace.h"
43 #include "opt_sched.h"
44
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kdb.h>
48 #include <sys/kernel.h>
49 #include <sys/ktr.h>
50 #include <sys/lock.h>
51 #include <sys/mutex.h>
52 #include <sys/proc.h>
53 #include <sys/resource.h>
54 #include <sys/resourcevar.h>
55 #include <sys/sched.h>
56 #include <sys/smp.h>
57 #include <sys/sx.h>
58 #include <sys/sysctl.h>
59 #include <sys/sysproto.h>
60 #include <sys/turnstile.h>
61 #include <sys/umtx.h>
62 #include <sys/vmmeter.h>
63 #include <sys/cpuset.h>
64 #include <sys/sbuf.h>
65
66 #ifdef HWPMC_HOOKS
67 #include <sys/pmckern.h>
68 #endif
69
70 #ifdef KDTRACE_HOOKS
71 #include <sys/dtrace_bsd.h>
72 int dtrace_vtime_active;
73 dtrace_vtime_switch_func_t dtrace_vtime_switch_func;
74 #endif
75
76 #include <machine/cpu.h>
77 #include <machine/smp.h>
78
79 #if defined(__sparc64__)
80 #error "This architecture is not currently compatible with ULE"
81 #endif
82
83 #define KTR_ULE 0
84
85 #define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX)))
86 #define TDQ_NAME_LEN (sizeof("sched lock ") + sizeof(__XSTRING(MAXCPU)))
87 #define TDQ_LOADNAME_LEN (sizeof("CPU ") + sizeof(__XSTRING(MAXCPU)) - 1 + sizeof(" load"))
88
89 /*
90 * Thread scheduler specific section. All fields are protected
91 * by the thread lock.
92 */
93 struct td_sched {
94 struct runq *ts_runq; /* Run-queue we're queued on. */
95 short ts_flags; /* TSF_* flags. */
96 u_char ts_cpu; /* CPU that we have affinity for. */
97 int ts_rltick; /* Real last tick, for affinity. */
98 int ts_slice; /* Ticks of slice remaining. */
99 u_int ts_slptime; /* Number of ticks we vol. slept */
100 u_int ts_runtime; /* Number of ticks we were running */
101 int ts_ltick; /* Last tick that we were running on */
102 int ts_incrtick; /* Last tick that we incremented on */
103 int ts_ftick; /* First tick that we were running on */
104 int ts_ticks; /* Tick count */
105 #ifdef KTR
106 char ts_name[TS_NAME_LEN];
107 #endif
108 };
109 /* flags kept in ts_flags */
110 #define TSF_BOUND 0x0001 /* Thread can not migrate. */
111 #define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */
112
113 static struct td_sched td_sched0;
114
115 #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0)
116 #define THREAD_CAN_SCHED(td, cpu) \
117 CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask)
118
119 /*
120 * Priority ranges used for interactive and non-interactive timeshare
121 * threads. The timeshare priorities are split up into four ranges.
122 * The first range handles interactive threads. The last three ranges
123 * (NHALF, x, and NHALF) handle non-interactive threads with the outer
124 * ranges supporting nice values.
125 */
126 #define PRI_TIMESHARE_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1)
127 #define PRI_INTERACT_RANGE ((PRI_TIMESHARE_RANGE - SCHED_PRI_NRESV) / 2)
128
129 #define PRI_MIN_INTERACT PRI_MIN_TIMESHARE
130 #define PRI_MAX_INTERACT (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE - 1)
131 #define PRI_MIN_BATCH (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE)
132 #define PRI_MAX_BATCH PRI_MAX_TIMESHARE
133
134 /*
135 * Cpu percentage computation macros and defines.
136 *
137 * SCHED_TICK_SECS: Number of seconds to average the cpu usage across.
138 * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across.
139 * SCHED_TICK_MAX: Maximum number of ticks before scaling back.
140 * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results.
141 * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count.
142 * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks.
143 */
144 #define SCHED_TICK_SECS 10
145 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS)
146 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz)
147 #define SCHED_TICK_SHIFT 10
148 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT)
149 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz))
150
151 /*
152 * These macros determine priorities for non-interactive threads. They are
153 * assigned a priority based on their recent cpu utilization as expressed
154 * by the ratio of ticks to the tick total. NHALF priorities at the start
155 * and end of the MIN to MAX timeshare range are only reachable with negative
156 * or positive nice respectively.
157 *
158 * PRI_RANGE: Priority range for utilization dependent priorities.
159 * PRI_NRESV: Number of nice values.
160 * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total.
161 * PRI_NICE: Determines the part of the priority inherited from nice.
162 */
163 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN)
164 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2)
165 #define SCHED_PRI_MIN (PRI_MIN_BATCH + SCHED_PRI_NHALF)
166 #define SCHED_PRI_MAX (PRI_MAX_BATCH - SCHED_PRI_NHALF)
167 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN + 1)
168 #define SCHED_PRI_TICKS(ts) \
169 (SCHED_TICK_HZ((ts)) / \
170 (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE))
171 #define SCHED_PRI_NICE(nice) (nice)
172
173 /*
174 * These determine the interactivity of a process. Interactivity differs from
175 * cpu utilization in that it expresses the voluntary time slept vs time ran
176 * while cpu utilization includes all time not running. This more accurately
177 * models the intent of the thread.
178 *
179 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate
180 * before throttling back.
181 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time.
182 * INTERACT_MAX: Maximum interactivity value. Smaller is better.
183 * INTERACT_THRESH: Threshold for placement on the current runq.
184 */
185 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT)
186 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT)
187 #define SCHED_INTERACT_MAX (100)
188 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2)
189 #define SCHED_INTERACT_THRESH (30)
190
191 /*
192 * tickincr: Converts a stathz tick into a hz domain scaled by
193 * the shift factor. Without the shift the error rate
194 * due to rounding would be unacceptably high.
195 * realstathz: stathz is sometimes 0 and run off of hz.
196 * sched_slice: Runtime of each thread before rescheduling.
197 * preempt_thresh: Priority threshold for preemption and remote IPIs.
198 */
199 static int sched_interact = SCHED_INTERACT_THRESH;
200 static int realstathz;
201 static int tickincr;
202 static int sched_slice = 1;
203 #ifdef PREEMPTION
204 #ifdef FULL_PREEMPTION
205 static int preempt_thresh = PRI_MAX_IDLE;
206 #else
207 static int preempt_thresh = PRI_MIN_KERN;
208 #endif
209 #else
210 static int preempt_thresh = 0;
211 #endif
212 static int static_boost = PRI_MIN_BATCH;
213 static int sched_idlespins = 10000;
214 static int sched_idlespinthresh = 16;
215
216 /*
217 * tdq - per processor runqs and statistics. All fields are protected by the
218 * tdq_lock. The load and lowpri may be accessed without to avoid excess
219 * locking in sched_pickcpu();
220 */
221 struct tdq {
222 /* Ordered to improve efficiency of cpu_search() and switch(). */
223 struct mtx tdq_lock; /* run queue lock. */
224 struct cpu_group *tdq_cg; /* Pointer to cpu topology. */
225 volatile int tdq_load; /* Aggregate load. */
226 volatile int tdq_cpu_idle; /* cpu_idle() is active. */
227 int tdq_sysload; /* For loadavg, !ITHD load. */
228 int tdq_transferable; /* Transferable thread count. */
229 short tdq_switchcnt; /* Switches this tick. */
230 short tdq_oldswitchcnt; /* Switches last tick. */
231 u_char tdq_lowpri; /* Lowest priority thread. */
232 u_char tdq_ipipending; /* IPI pending. */
233 u_char tdq_idx; /* Current insert index. */
234 u_char tdq_ridx; /* Current removal index. */
235 struct runq tdq_realtime; /* real-time run queue. */
236 struct runq tdq_timeshare; /* timeshare run queue. */
237 struct runq tdq_idle; /* Queue of IDLE threads. */
238 char tdq_name[TDQ_NAME_LEN];
239 #ifdef KTR
240 char tdq_loadname[TDQ_LOADNAME_LEN];
241 #endif
242 } __aligned(64);
243
244 /* Idle thread states and config. */
245 #define TDQ_RUNNING 1
246 #define TDQ_IDLE 2
247
248 #ifdef SMP
249 struct cpu_group *cpu_top; /* CPU topology */
250
251 #define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000))
252 #define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity))
253
254 /*
255 * Run-time tunables.
256 */
257 static int rebalance = 1;
258 static int balance_interval = 128; /* Default set in sched_initticks(). */
259 static int affinity;
260 static int steal_htt = 1;
261 static int steal_idle = 1;
262 static int steal_thresh = 2;
263
264 /*
265 * One thread queue per processor.
266 */
267 static struct tdq tdq_cpu[MAXCPU];
268 static struct tdq *balance_tdq;
269 static int balance_ticks;
270
271 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)])
272 #define TDQ_CPU(x) (&tdq_cpu[(x)])
273 #define TDQ_ID(x) ((int)((x) - tdq_cpu))
274 #else /* !SMP */
275 static struct tdq tdq_cpu;
276
277 #define TDQ_ID(x) (0)
278 #define TDQ_SELF() (&tdq_cpu)
279 #define TDQ_CPU(x) (&tdq_cpu)
280 #endif
281
282 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type))
283 #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t)))
284 #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f))
285 #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t)))
286 #define TDQ_LOCKPTR(t) (&(t)->tdq_lock)
287
288 static void sched_priority(struct thread *);
289 static void sched_thread_priority(struct thread *, u_char);
290 static int sched_interact_score(struct thread *);
291 static void sched_interact_update(struct thread *);
292 static void sched_interact_fork(struct thread *);
293 static void sched_pctcpu_update(struct td_sched *);
294
295 /* Operations on per processor queues */
296 static struct thread *tdq_choose(struct tdq *);
297 static void tdq_setup(struct tdq *);
298 static void tdq_load_add(struct tdq *, struct thread *);
299 static void tdq_load_rem(struct tdq *, struct thread *);
300 static __inline void tdq_runq_add(struct tdq *, struct thread *, int);
301 static __inline void tdq_runq_rem(struct tdq *, struct thread *);
302 static inline int sched_shouldpreempt(int, int, int);
303 void tdq_print(int cpu);
304 static void runq_print(struct runq *rq);
305 static void tdq_add(struct tdq *, struct thread *, int);
306 #ifdef SMP
307 static int tdq_move(struct tdq *, struct tdq *);
308 static int tdq_idled(struct tdq *);
309 static void tdq_notify(struct tdq *, struct thread *);
310 static struct thread *tdq_steal(struct tdq *, int);
311 static struct thread *runq_steal(struct runq *, int);
312 static int sched_pickcpu(struct thread *, int);
313 static void sched_balance(void);
314 static int sched_balance_pair(struct tdq *, struct tdq *);
315 static inline struct tdq *sched_setcpu(struct thread *, int, int);
316 static inline void thread_unblock_switch(struct thread *, struct mtx *);
317 static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int);
318 static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS);
319 static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb,
320 struct cpu_group *cg, int indent);
321 #endif
322
323 static void sched_setup(void *dummy);
324 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
325
326 static void sched_initticks(void *dummy);
327 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks,
328 NULL);
329
330 /*
331 * Print the threads waiting on a run-queue.
332 */
333 static void
334 runq_print(struct runq *rq)
335 {
336 struct rqhead *rqh;
337 struct thread *td;
338 int pri;
339 int j;
340 int i;
341
342 for (i = 0; i < RQB_LEN; i++) {
343 printf("\t\trunq bits %d 0x%zx\n",
344 i, rq->rq_status.rqb_bits[i]);
345 for (j = 0; j < RQB_BPW; j++)
346 if (rq->rq_status.rqb_bits[i] & (1ul << j)) {
347 pri = j + (i << RQB_L2BPW);
348 rqh = &rq->rq_queues[pri];
349 TAILQ_FOREACH(td, rqh, td_runq) {
350 printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n",
351 td, td->td_name, td->td_priority,
352 td->td_rqindex, pri);
353 }
354 }
355 }
356 }
357
358 /*
359 * Print the status of a per-cpu thread queue. Should be a ddb show cmd.
360 */
361 void
362 tdq_print(int cpu)
363 {
364 struct tdq *tdq;
365
366 tdq = TDQ_CPU(cpu);
367
368 printf("tdq %d:\n", TDQ_ID(tdq));
369 printf("\tlock %p\n", TDQ_LOCKPTR(tdq));
370 printf("\tLock name: %s\n", tdq->tdq_name);
371 printf("\tload: %d\n", tdq->tdq_load);
372 printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt);
373 printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt);
374 printf("\ttimeshare idx: %d\n", tdq->tdq_idx);
375 printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx);
376 printf("\tload transferable: %d\n", tdq->tdq_transferable);
377 printf("\tlowest priority: %d\n", tdq->tdq_lowpri);
378 printf("\trealtime runq:\n");
379 runq_print(&tdq->tdq_realtime);
380 printf("\ttimeshare runq:\n");
381 runq_print(&tdq->tdq_timeshare);
382 printf("\tidle runq:\n");
383 runq_print(&tdq->tdq_idle);
384 }
385
386 static inline int
387 sched_shouldpreempt(int pri, int cpri, int remote)
388 {
389 /*
390 * If the new priority is not better than the current priority there is
391 * nothing to do.
392 */
393 if (pri >= cpri)
394 return (0);
395 /*
396 * Always preempt idle.
397 */
398 if (cpri >= PRI_MIN_IDLE)
399 return (1);
400 /*
401 * If preemption is disabled don't preempt others.
402 */
403 if (preempt_thresh == 0)
404 return (0);
405 /*
406 * Preempt if we exceed the threshold.
407 */
408 if (pri <= preempt_thresh)
409 return (1);
410 /*
411 * If we're interactive or better and there is non-interactive
412 * or worse running preempt only remote processors.
413 */
414 if (remote && pri <= PRI_MAX_INTERACT && cpri > PRI_MAX_INTERACT)
415 return (1);
416 return (0);
417 }
418
419 #define TS_RQ_PPQ (((PRI_MAX_BATCH - PRI_MIN_BATCH) + 1) / RQ_NQS)
420 /*
421 * Add a thread to the actual run-queue. Keeps transferable counts up to
422 * date with what is actually on the run-queue. Selects the correct
423 * queue position for timeshare threads.
424 */
425 static __inline void
426 tdq_runq_add(struct tdq *tdq, struct thread *td, int flags)
427 {
428 struct td_sched *ts;
429 u_char pri;
430
431 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
432 THREAD_LOCK_ASSERT(td, MA_OWNED);
433
434 pri = td->td_priority;
435 ts = td->td_sched;
436 TD_SET_RUNQ(td);
437 if (THREAD_CAN_MIGRATE(td)) {
438 tdq->tdq_transferable++;
439 ts->ts_flags |= TSF_XFERABLE;
440 }
441 if (pri < PRI_MIN_BATCH) {
442 ts->ts_runq = &tdq->tdq_realtime;
443 } else if (pri <= PRI_MAX_BATCH) {
444 ts->ts_runq = &tdq->tdq_timeshare;
445 KASSERT(pri <= PRI_MAX_BATCH && pri >= PRI_MIN_BATCH,
446 ("Invalid priority %d on timeshare runq", pri));
447 /*
448 * This queue contains only priorities between MIN and MAX
449 * realtime. Use the whole queue to represent these values.
450 */
451 if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) {
452 pri = (pri - PRI_MIN_BATCH) / TS_RQ_PPQ;
453 pri = (pri + tdq->tdq_idx) % RQ_NQS;
454 /*
455 * This effectively shortens the queue by one so we
456 * can have a one slot difference between idx and
457 * ridx while we wait for threads to drain.
458 */
459 if (tdq->tdq_ridx != tdq->tdq_idx &&
460 pri == tdq->tdq_ridx)
461 pri = (unsigned char)(pri - 1) % RQ_NQS;
462 } else
463 pri = tdq->tdq_ridx;
464 runq_add_pri(ts->ts_runq, td, pri, flags);
465 return;
466 } else
467 ts->ts_runq = &tdq->tdq_idle;
468 runq_add(ts->ts_runq, td, flags);
469 }
470
471 /*
472 * Remove a thread from a run-queue. This typically happens when a thread
473 * is selected to run. Running threads are not on the queue and the
474 * transferable count does not reflect them.
475 */
476 static __inline void
477 tdq_runq_rem(struct tdq *tdq, struct thread *td)
478 {
479 struct td_sched *ts;
480
481 ts = td->td_sched;
482 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
483 KASSERT(ts->ts_runq != NULL,
484 ("tdq_runq_remove: thread %p null ts_runq", td));
485 if (ts->ts_flags & TSF_XFERABLE) {
486 tdq->tdq_transferable--;
487 ts->ts_flags &= ~TSF_XFERABLE;
488 }
489 if (ts->ts_runq == &tdq->tdq_timeshare) {
490 if (tdq->tdq_idx != tdq->tdq_ridx)
491 runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx);
492 else
493 runq_remove_idx(ts->ts_runq, td, NULL);
494 } else
495 runq_remove(ts->ts_runq, td);
496 }
497
498 /*
499 * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load
500 * for this thread to the referenced thread queue.
501 */
502 static void
503 tdq_load_add(struct tdq *tdq, struct thread *td)
504 {
505
506 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
507 THREAD_LOCK_ASSERT(td, MA_OWNED);
508
509 tdq->tdq_load++;
510 if ((td->td_flags & TDF_NOLOAD) == 0)
511 tdq->tdq_sysload++;
512 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
513 }
514
515 /*
516 * Remove the load from a thread that is transitioning to a sleep state or
517 * exiting.
518 */
519 static void
520 tdq_load_rem(struct tdq *tdq, struct thread *td)
521 {
522
523 THREAD_LOCK_ASSERT(td, MA_OWNED);
524 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
525 KASSERT(tdq->tdq_load != 0,
526 ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq)));
527
528 tdq->tdq_load--;
529 if ((td->td_flags & TDF_NOLOAD) == 0)
530 tdq->tdq_sysload--;
531 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
532 }
533
534 /*
535 * Set lowpri to its exact value by searching the run-queue and
536 * evaluating curthread. curthread may be passed as an optimization.
537 */
538 static void
539 tdq_setlowpri(struct tdq *tdq, struct thread *ctd)
540 {
541 struct thread *td;
542
543 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
544 if (ctd == NULL)
545 ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread;
546 td = tdq_choose(tdq);
547 if (td == NULL || td->td_priority > ctd->td_priority)
548 tdq->tdq_lowpri = ctd->td_priority;
549 else
550 tdq->tdq_lowpri = td->td_priority;
551 }
552
553 #ifdef SMP
554 struct cpu_search {
555 cpuset_t cs_mask;
556 u_int cs_load;
557 u_int cs_cpu;
558 int cs_limit; /* Min priority for low min load for high. */
559 };
560
561 #define CPU_SEARCH_LOWEST 0x1
562 #define CPU_SEARCH_HIGHEST 0x2
563 #define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST)
564
565 #define CPUSET_FOREACH(cpu, mask) \
566 for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++) \
567 if (CPU_ISSET(cpu, &mask))
568
569 static __inline int cpu_search(struct cpu_group *cg, struct cpu_search *low,
570 struct cpu_search *high, const int match);
571 int cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low);
572 int cpu_search_highest(struct cpu_group *cg, struct cpu_search *high);
573 int cpu_search_both(struct cpu_group *cg, struct cpu_search *low,
574 struct cpu_search *high);
575
576 /*
577 * This routine compares according to the match argument and should be
578 * reduced in actual instantiations via constant propagation and dead code
579 * elimination.
580 */
581 static __inline int
582 cpu_compare(int cpu, struct cpu_search *low, struct cpu_search *high,
583 const int match)
584 {
585 struct tdq *tdq;
586
587 tdq = TDQ_CPU(cpu);
588 if (match & CPU_SEARCH_LOWEST)
589 if (CPU_ISSET(cpu, &low->cs_mask) &&
590 tdq->tdq_load < low->cs_load &&
591 tdq->tdq_lowpri > low->cs_limit) {
592 low->cs_cpu = cpu;
593 low->cs_load = tdq->tdq_load;
594 }
595 if (match & CPU_SEARCH_HIGHEST)
596 if (CPU_ISSET(cpu, &high->cs_mask) &&
597 tdq->tdq_load >= high->cs_limit &&
598 tdq->tdq_load > high->cs_load &&
599 tdq->tdq_transferable) {
600 high->cs_cpu = cpu;
601 high->cs_load = tdq->tdq_load;
602 }
603 return (tdq->tdq_load);
604 }
605
606 /*
607 * Search the tree of cpu_groups for the lowest or highest loaded cpu
608 * according to the match argument. This routine actually compares the
609 * load on all paths through the tree and finds the least loaded cpu on
610 * the least loaded path, which may differ from the least loaded cpu in
611 * the system. This balances work among caches and busses.
612 *
613 * This inline is instantiated in three forms below using constants for the
614 * match argument. It is reduced to the minimum set for each case. It is
615 * also recursive to the depth of the tree.
616 */
617 static __inline int
618 cpu_search(struct cpu_group *cg, struct cpu_search *low,
619 struct cpu_search *high, const int match)
620 {
621 int total;
622
623 total = 0;
624 if (cg->cg_children) {
625 struct cpu_search lgroup;
626 struct cpu_search hgroup;
627 struct cpu_group *child;
628 u_int lload;
629 int hload;
630 int load;
631 int i;
632
633 lload = -1;
634 hload = -1;
635 for (i = 0; i < cg->cg_children; i++) {
636 child = &cg->cg_child[i];
637 if (match & CPU_SEARCH_LOWEST) {
638 lgroup = *low;
639 lgroup.cs_load = -1;
640 }
641 if (match & CPU_SEARCH_HIGHEST) {
642 hgroup = *high;
643 lgroup.cs_load = 0;
644 }
645 switch (match) {
646 case CPU_SEARCH_LOWEST:
647 load = cpu_search_lowest(child, &lgroup);
648 break;
649 case CPU_SEARCH_HIGHEST:
650 load = cpu_search_highest(child, &hgroup);
651 break;
652 case CPU_SEARCH_BOTH:
653 load = cpu_search_both(child, &lgroup, &hgroup);
654 break;
655 }
656 total += load;
657 if (match & CPU_SEARCH_LOWEST)
658 if (load < lload || low->cs_cpu == -1) {
659 *low = lgroup;
660 lload = load;
661 }
662 if (match & CPU_SEARCH_HIGHEST)
663 if (load > hload || high->cs_cpu == -1) {
664 hload = load;
665 *high = hgroup;
666 }
667 }
668 } else {
669 int cpu;
670
671 CPUSET_FOREACH(cpu, cg->cg_mask)
672 total += cpu_compare(cpu, low, high, match);
673 }
674 return (total);
675 }
676
677 /*
678 * cpu_search instantiations must pass constants to maintain the inline
679 * optimization.
680 */
681 int
682 cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low)
683 {
684 return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST);
685 }
686
687 int
688 cpu_search_highest(struct cpu_group *cg, struct cpu_search *high)
689 {
690 return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST);
691 }
692
693 int
694 cpu_search_both(struct cpu_group *cg, struct cpu_search *low,
695 struct cpu_search *high)
696 {
697 return cpu_search(cg, low, high, CPU_SEARCH_BOTH);
698 }
699
700 /*
701 * Find the cpu with the least load via the least loaded path that has a
702 * lowpri greater than pri pri. A pri of -1 indicates any priority is
703 * acceptable.
704 */
705 static inline int
706 sched_lowest(struct cpu_group *cg, cpuset_t mask, int pri)
707 {
708 struct cpu_search low;
709
710 low.cs_cpu = -1;
711 low.cs_load = -1;
712 low.cs_mask = mask;
713 low.cs_limit = pri;
714 cpu_search_lowest(cg, &low);
715 return low.cs_cpu;
716 }
717
718 /*
719 * Find the cpu with the highest load via the highest loaded path.
720 */
721 static inline int
722 sched_highest(struct cpu_group *cg, cpuset_t mask, int minload)
723 {
724 struct cpu_search high;
725
726 high.cs_cpu = -1;
727 high.cs_load = 0;
728 high.cs_mask = mask;
729 high.cs_limit = minload;
730 cpu_search_highest(cg, &high);
731 return high.cs_cpu;
732 }
733
734 /*
735 * Simultaneously find the highest and lowest loaded cpu reachable via
736 * cg.
737 */
738 static inline void
739 sched_both(struct cpu_group *cg, cpuset_t mask, int *lowcpu, int *highcpu)
740 {
741 struct cpu_search high;
742 struct cpu_search low;
743
744 low.cs_cpu = -1;
745 low.cs_limit = -1;
746 low.cs_load = -1;
747 low.cs_mask = mask;
748 high.cs_load = 0;
749 high.cs_cpu = -1;
750 high.cs_limit = -1;
751 high.cs_mask = mask;
752 cpu_search_both(cg, &low, &high);
753 *lowcpu = low.cs_cpu;
754 *highcpu = high.cs_cpu;
755 return;
756 }
757
758 static void
759 sched_balance_group(struct cpu_group *cg)
760 {
761 cpuset_t mask;
762 int high;
763 int low;
764 int i;
765
766 CPU_FILL(&mask);
767 for (;;) {
768 sched_both(cg, mask, &low, &high);
769 if (low == high || low == -1 || high == -1)
770 break;
771 if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low)))
772 break;
773 /*
774 * If we failed to move any threads determine which cpu
775 * to kick out of the set and try again.
776 */
777 if (TDQ_CPU(high)->tdq_transferable == 0)
778 CPU_CLR(high, &mask);
779 else
780 CPU_CLR(low, &mask);
781 }
782
783 for (i = 0; i < cg->cg_children; i++)
784 sched_balance_group(&cg->cg_child[i]);
785 }
786
787 static void
788 sched_balance(void)
789 {
790 struct tdq *tdq;
791
792 /*
793 * Select a random time between .5 * balance_interval and
794 * 1.5 * balance_interval.
795 */
796 balance_ticks = max(balance_interval / 2, 1);
797 balance_ticks += random() % balance_interval;
798 if (smp_started == 0 || rebalance == 0)
799 return;
800 tdq = TDQ_SELF();
801 TDQ_UNLOCK(tdq);
802 sched_balance_group(cpu_top);
803 TDQ_LOCK(tdq);
804 }
805
806 /*
807 * Lock two thread queues using their address to maintain lock order.
808 */
809 static void
810 tdq_lock_pair(struct tdq *one, struct tdq *two)
811 {
812 if (one < two) {
813 TDQ_LOCK(one);
814 TDQ_LOCK_FLAGS(two, MTX_DUPOK);
815 } else {
816 TDQ_LOCK(two);
817 TDQ_LOCK_FLAGS(one, MTX_DUPOK);
818 }
819 }
820
821 /*
822 * Unlock two thread queues. Order is not important here.
823 */
824 static void
825 tdq_unlock_pair(struct tdq *one, struct tdq *two)
826 {
827 TDQ_UNLOCK(one);
828 TDQ_UNLOCK(two);
829 }
830
831 /*
832 * Transfer load between two imbalanced thread queues.
833 */
834 static int
835 sched_balance_pair(struct tdq *high, struct tdq *low)
836 {
837 int transferable;
838 int high_load;
839 int low_load;
840 int moved;
841 int move;
842 int diff;
843 int i;
844
845 tdq_lock_pair(high, low);
846 transferable = high->tdq_transferable;
847 high_load = high->tdq_load;
848 low_load = low->tdq_load;
849 moved = 0;
850 /*
851 * Determine what the imbalance is and then adjust that to how many
852 * threads we actually have to give up (transferable).
853 */
854 if (transferable != 0) {
855 diff = high_load - low_load;
856 move = diff / 2;
857 if (diff & 0x1)
858 move++;
859 move = min(move, transferable);
860 for (i = 0; i < move; i++)
861 moved += tdq_move(high, low);
862 /*
863 * IPI the target cpu to force it to reschedule with the new
864 * workload.
865 */
866 ipi_cpu(TDQ_ID(low), IPI_PREEMPT);
867 }
868 tdq_unlock_pair(high, low);
869 return (moved);
870 }
871
872 /*
873 * Move a thread from one thread queue to another.
874 */
875 static int
876 tdq_move(struct tdq *from, struct tdq *to)
877 {
878 struct td_sched *ts;
879 struct thread *td;
880 struct tdq *tdq;
881 int cpu;
882
883 TDQ_LOCK_ASSERT(from, MA_OWNED);
884 TDQ_LOCK_ASSERT(to, MA_OWNED);
885
886 tdq = from;
887 cpu = TDQ_ID(to);
888 td = tdq_steal(tdq, cpu);
889 if (td == NULL)
890 return (0);
891 ts = td->td_sched;
892 /*
893 * Although the run queue is locked the thread may be blocked. Lock
894 * it to clear this and acquire the run-queue lock.
895 */
896 thread_lock(td);
897 /* Drop recursive lock on from acquired via thread_lock(). */
898 TDQ_UNLOCK(from);
899 sched_rem(td);
900 ts->ts_cpu = cpu;
901 td->td_lock = TDQ_LOCKPTR(to);
902 tdq_add(to, td, SRQ_YIELDING);
903 return (1);
904 }
905
906 /*
907 * This tdq has idled. Try to steal a thread from another cpu and switch
908 * to it.
909 */
910 static int
911 tdq_idled(struct tdq *tdq)
912 {
913 struct cpu_group *cg;
914 struct tdq *steal;
915 cpuset_t mask;
916 int thresh;
917 int cpu;
918
919 if (smp_started == 0 || steal_idle == 0)
920 return (1);
921 CPU_FILL(&mask);
922 CPU_CLR(PCPU_GET(cpuid), &mask);
923 /* We don't want to be preempted while we're iterating. */
924 spinlock_enter();
925 for (cg = tdq->tdq_cg; cg != NULL; ) {
926 if ((cg->cg_flags & CG_FLAG_THREAD) == 0)
927 thresh = steal_thresh;
928 else
929 thresh = 1;
930 cpu = sched_highest(cg, mask, thresh);
931 if (cpu == -1) {
932 cg = cg->cg_parent;
933 continue;
934 }
935 steal = TDQ_CPU(cpu);
936 CPU_CLR(cpu, &mask);
937 tdq_lock_pair(tdq, steal);
938 if (steal->tdq_load < thresh || steal->tdq_transferable == 0) {
939 tdq_unlock_pair(tdq, steal);
940 continue;
941 }
942 /*
943 * If a thread was added while interrupts were disabled don't
944 * steal one here. If we fail to acquire one due to affinity
945 * restrictions loop again with this cpu removed from the
946 * set.
947 */
948 if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) {
949 tdq_unlock_pair(tdq, steal);
950 continue;
951 }
952 spinlock_exit();
953 TDQ_UNLOCK(steal);
954 mi_switch(SW_VOL | SWT_IDLE, NULL);
955 thread_unlock(curthread);
956
957 return (0);
958 }
959 spinlock_exit();
960 return (1);
961 }
962
963 /*
964 * Notify a remote cpu of new work. Sends an IPI if criteria are met.
965 */
966 static void
967 tdq_notify(struct tdq *tdq, struct thread *td)
968 {
969 struct thread *ctd;
970 int pri;
971 int cpu;
972
973 if (tdq->tdq_ipipending)
974 return;
975 cpu = td->td_sched->ts_cpu;
976 pri = td->td_priority;
977 ctd = pcpu_find(cpu)->pc_curthread;
978 if (!sched_shouldpreempt(pri, ctd->td_priority, 1))
979 return;
980 if (TD_IS_IDLETHREAD(ctd)) {
981 /*
982 * If the MD code has an idle wakeup routine try that before
983 * falling back to IPI.
984 */
985 if (!tdq->tdq_cpu_idle || cpu_idle_wakeup(cpu))
986 return;
987 }
988 tdq->tdq_ipipending = 1;
989 ipi_cpu(cpu, IPI_PREEMPT);
990 }
991
992 /*
993 * Steals load from a timeshare queue. Honors the rotating queue head
994 * index.
995 */
996 static struct thread *
997 runq_steal_from(struct runq *rq, int cpu, u_char start)
998 {
999 struct rqbits *rqb;
1000 struct rqhead *rqh;
1001 struct thread *td;
1002 int first;
1003 int bit;
1004 int pri;
1005 int i;
1006
1007 rqb = &rq->rq_status;
1008 bit = start & (RQB_BPW -1);
1009 pri = 0;
1010 first = 0;
1011 again:
1012 for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) {
1013 if (rqb->rqb_bits[i] == 0)
1014 continue;
1015 if (bit != 0) {
1016 for (pri = bit; pri < RQB_BPW; pri++)
1017 if (rqb->rqb_bits[i] & (1ul << pri))
1018 break;
1019 if (pri >= RQB_BPW)
1020 continue;
1021 } else
1022 pri = RQB_FFS(rqb->rqb_bits[i]);
1023 pri += (i << RQB_L2BPW);
1024 rqh = &rq->rq_queues[pri];
1025 TAILQ_FOREACH(td, rqh, td_runq) {
1026 if (first && THREAD_CAN_MIGRATE(td) &&
1027 THREAD_CAN_SCHED(td, cpu))
1028 return (td);
1029 first = 1;
1030 }
1031 }
1032 if (start != 0) {
1033 start = 0;
1034 goto again;
1035 }
1036
1037 return (NULL);
1038 }
1039
1040 /*
1041 * Steals load from a standard linear queue.
1042 */
1043 static struct thread *
1044 runq_steal(struct runq *rq, int cpu)
1045 {
1046 struct rqhead *rqh;
1047 struct rqbits *rqb;
1048 struct thread *td;
1049 int word;
1050 int bit;
1051
1052 rqb = &rq->rq_status;
1053 for (word = 0; word < RQB_LEN; word++) {
1054 if (rqb->rqb_bits[word] == 0)
1055 continue;
1056 for (bit = 0; bit < RQB_BPW; bit++) {
1057 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0)
1058 continue;
1059 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)];
1060 TAILQ_FOREACH(td, rqh, td_runq)
1061 if (THREAD_CAN_MIGRATE(td) &&
1062 THREAD_CAN_SCHED(td, cpu))
1063 return (td);
1064 }
1065 }
1066 return (NULL);
1067 }
1068
1069 /*
1070 * Attempt to steal a thread in priority order from a thread queue.
1071 */
1072 static struct thread *
1073 tdq_steal(struct tdq *tdq, int cpu)
1074 {
1075 struct thread *td;
1076
1077 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1078 if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL)
1079 return (td);
1080 if ((td = runq_steal_from(&tdq->tdq_timeshare,
1081 cpu, tdq->tdq_ridx)) != NULL)
1082 return (td);
1083 return (runq_steal(&tdq->tdq_idle, cpu));
1084 }
1085
1086 /*
1087 * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the
1088 * current lock and returns with the assigned queue locked.
1089 */
1090 static inline struct tdq *
1091 sched_setcpu(struct thread *td, int cpu, int flags)
1092 {
1093
1094 struct tdq *tdq;
1095
1096 THREAD_LOCK_ASSERT(td, MA_OWNED);
1097 tdq = TDQ_CPU(cpu);
1098 td->td_sched->ts_cpu = cpu;
1099 /*
1100 * If the lock matches just return the queue.
1101 */
1102 if (td->td_lock == TDQ_LOCKPTR(tdq))
1103 return (tdq);
1104 #ifdef notyet
1105 /*
1106 * If the thread isn't running its lockptr is a
1107 * turnstile or a sleepqueue. We can just lock_set without
1108 * blocking.
1109 */
1110 if (TD_CAN_RUN(td)) {
1111 TDQ_LOCK(tdq);
1112 thread_lock_set(td, TDQ_LOCKPTR(tdq));
1113 return (tdq);
1114 }
1115 #endif
1116 /*
1117 * The hard case, migration, we need to block the thread first to
1118 * prevent order reversals with other cpus locks.
1119 */
1120 spinlock_enter();
1121 thread_lock_block(td);
1122 TDQ_LOCK(tdq);
1123 thread_lock_unblock(td, TDQ_LOCKPTR(tdq));
1124 spinlock_exit();
1125 return (tdq);
1126 }
1127
1128 SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding");
1129 SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity");
1130 SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity");
1131 SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load");
1132 SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu");
1133 SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration");
1134
1135 static int
1136 sched_pickcpu(struct thread *td, int flags)
1137 {
1138 struct cpu_group *cg;
1139 struct td_sched *ts;
1140 struct tdq *tdq;
1141 cpuset_t mask;
1142 int self;
1143 int pri;
1144 int cpu;
1145
1146 self = PCPU_GET(cpuid);
1147 ts = td->td_sched;
1148 if (smp_started == 0)
1149 return (self);
1150 /*
1151 * Don't migrate a running thread from sched_switch().
1152 */
1153 if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td))
1154 return (ts->ts_cpu);
1155 /*
1156 * Prefer to run interrupt threads on the processors that generate
1157 * the interrupt.
1158 */
1159 if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) &&
1160 curthread->td_intr_nesting_level && ts->ts_cpu != self) {
1161 SCHED_STAT_INC(pickcpu_intrbind);
1162 ts->ts_cpu = self;
1163 }
1164 /*
1165 * If the thread can run on the last cpu and the affinity has not
1166 * expired or it is idle run it there.
1167 */
1168 pri = td->td_priority;
1169 tdq = TDQ_CPU(ts->ts_cpu);
1170 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) {
1171 if (tdq->tdq_lowpri > PRI_MIN_IDLE) {
1172 SCHED_STAT_INC(pickcpu_idle_affinity);
1173 return (ts->ts_cpu);
1174 }
1175 if (SCHED_AFFINITY(ts, CG_SHARE_L2) && tdq->tdq_lowpri > pri) {
1176 SCHED_STAT_INC(pickcpu_affinity);
1177 return (ts->ts_cpu);
1178 }
1179 }
1180 /*
1181 * Search for the highest level in the tree that still has affinity.
1182 */
1183 cg = NULL;
1184 for (cg = tdq->tdq_cg; cg != NULL; cg = cg->cg_parent)
1185 if (SCHED_AFFINITY(ts, cg->cg_level))
1186 break;
1187 cpu = -1;
1188 mask = td->td_cpuset->cs_mask;
1189 if (cg)
1190 cpu = sched_lowest(cg, mask, pri);
1191 if (cpu == -1)
1192 cpu = sched_lowest(cpu_top, mask, -1);
1193 /*
1194 * Compare the lowest loaded cpu to current cpu.
1195 */
1196 if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri &&
1197 TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE) {
1198 SCHED_STAT_INC(pickcpu_local);
1199 cpu = self;
1200 } else
1201 SCHED_STAT_INC(pickcpu_lowest);
1202 if (cpu != ts->ts_cpu)
1203 SCHED_STAT_INC(pickcpu_migration);
1204 KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu."));
1205 return (cpu);
1206 }
1207 #endif
1208
1209 /*
1210 * Pick the highest priority task we have and return it.
1211 */
1212 static struct thread *
1213 tdq_choose(struct tdq *tdq)
1214 {
1215 struct thread *td;
1216
1217 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
1218 td = runq_choose(&tdq->tdq_realtime);
1219 if (td != NULL)
1220 return (td);
1221 td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx);
1222 if (td != NULL) {
1223 KASSERT(td->td_priority >= PRI_MIN_BATCH,
1224 ("tdq_choose: Invalid priority on timeshare queue %d",
1225 td->td_priority));
1226 return (td);
1227 }
1228 td = runq_choose(&tdq->tdq_idle);
1229 if (td != NULL) {
1230 KASSERT(td->td_priority >= PRI_MIN_IDLE,
1231 ("tdq_choose: Invalid priority on idle queue %d",
1232 td->td_priority));
1233 return (td);
1234 }
1235
1236 return (NULL);
1237 }
1238
1239 /*
1240 * Initialize a thread queue.
1241 */
1242 static void
1243 tdq_setup(struct tdq *tdq)
1244 {
1245
1246 if (bootverbose)
1247 printf("ULE: setup cpu %d\n", TDQ_ID(tdq));
1248 runq_init(&tdq->tdq_realtime);
1249 runq_init(&tdq->tdq_timeshare);
1250 runq_init(&tdq->tdq_idle);
1251 snprintf(tdq->tdq_name, sizeof(tdq->tdq_name),
1252 "sched lock %d", (int)TDQ_ID(tdq));
1253 mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock",
1254 MTX_SPIN | MTX_RECURSE);
1255 #ifdef KTR
1256 snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname),
1257 "CPU %d load", (int)TDQ_ID(tdq));
1258 #endif
1259 }
1260
1261 #ifdef SMP
1262 static void
1263 sched_setup_smp(void)
1264 {
1265 struct tdq *tdq;
1266 int i;
1267
1268 cpu_top = smp_topo();
1269 CPU_FOREACH(i) {
1270 tdq = TDQ_CPU(i);
1271 tdq_setup(tdq);
1272 tdq->tdq_cg = smp_topo_find(cpu_top, i);
1273 if (tdq->tdq_cg == NULL)
1274 panic("Can't find cpu group for %d\n", i);
1275 }
1276 balance_tdq = TDQ_SELF();
1277 sched_balance();
1278 }
1279 #endif
1280
1281 /*
1282 * Setup the thread queues and initialize the topology based on MD
1283 * information.
1284 */
1285 static void
1286 sched_setup(void *dummy)
1287 {
1288 struct tdq *tdq;
1289
1290 tdq = TDQ_SELF();
1291 #ifdef SMP
1292 sched_setup_smp();
1293 #else
1294 tdq_setup(tdq);
1295 #endif
1296 /*
1297 * To avoid divide-by-zero, we set realstathz a dummy value
1298 * in case which sched_clock() called before sched_initticks().
1299 */
1300 realstathz = hz;
1301 sched_slice = (realstathz/10); /* ~100ms */
1302 tickincr = 1 << SCHED_TICK_SHIFT;
1303
1304 /* Add thread0's load since it's running. */
1305 TDQ_LOCK(tdq);
1306 thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF());
1307 tdq_load_add(tdq, &thread0);
1308 tdq->tdq_lowpri = thread0.td_priority;
1309 TDQ_UNLOCK(tdq);
1310 }
1311
1312 /*
1313 * This routine determines the tickincr after stathz and hz are setup.
1314 */
1315 /* ARGSUSED */
1316 static void
1317 sched_initticks(void *dummy)
1318 {
1319 int incr;
1320
1321 realstathz = stathz ? stathz : hz;
1322 sched_slice = (realstathz/10); /* ~100ms */
1323
1324 /*
1325 * tickincr is shifted out by 10 to avoid rounding errors due to
1326 * hz not being evenly divisible by stathz on all platforms.
1327 */
1328 incr = (hz << SCHED_TICK_SHIFT) / realstathz;
1329 /*
1330 * This does not work for values of stathz that are more than
1331 * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen.
1332 */
1333 if (incr == 0)
1334 incr = 1;
1335 tickincr = incr;
1336 #ifdef SMP
1337 /*
1338 * Set the default balance interval now that we know
1339 * what realstathz is.
1340 */
1341 balance_interval = realstathz;
1342 /*
1343 * Set steal thresh to roughly log2(mp_ncpu) but no greater than 4.
1344 * This prevents excess thrashing on large machines and excess idle
1345 * on smaller machines.
1346 */
1347 steal_thresh = min(fls(mp_ncpus) - 1, 3);
1348 affinity = SCHED_AFFINITY_DEFAULT;
1349 #endif
1350 }
1351
1352
1353 /*
1354 * This is the core of the interactivity algorithm. Determines a score based
1355 * on past behavior. It is the ratio of sleep time to run time scaled to
1356 * a [0, 100] integer. This is the voluntary sleep time of a process, which
1357 * differs from the cpu usage because it does not account for time spent
1358 * waiting on a run-queue. Would be prettier if we had floating point.
1359 */
1360 static int
1361 sched_interact_score(struct thread *td)
1362 {
1363 struct td_sched *ts;
1364 int div;
1365
1366 ts = td->td_sched;
1367 /*
1368 * The score is only needed if this is likely to be an interactive
1369 * task. Don't go through the expense of computing it if there's
1370 * no chance.
1371 */
1372 if (sched_interact <= SCHED_INTERACT_HALF &&
1373 ts->ts_runtime >= ts->ts_slptime)
1374 return (SCHED_INTERACT_HALF);
1375
1376 if (ts->ts_runtime > ts->ts_slptime) {
1377 div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF);
1378 return (SCHED_INTERACT_HALF +
1379 (SCHED_INTERACT_HALF - (ts->ts_slptime / div)));
1380 }
1381 if (ts->ts_slptime > ts->ts_runtime) {
1382 div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF);
1383 return (ts->ts_runtime / div);
1384 }
1385 /* runtime == slptime */
1386 if (ts->ts_runtime)
1387 return (SCHED_INTERACT_HALF);
1388
1389 /*
1390 * This can happen if slptime and runtime are 0.
1391 */
1392 return (0);
1393
1394 }
1395
1396 /*
1397 * Scale the scheduling priority according to the "interactivity" of this
1398 * process.
1399 */
1400 static void
1401 sched_priority(struct thread *td)
1402 {
1403 int score;
1404 int pri;
1405
1406 if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
1407 return;
1408 /*
1409 * If the score is interactive we place the thread in the realtime
1410 * queue with a priority that is less than kernel and interrupt
1411 * priorities. These threads are not subject to nice restrictions.
1412 *
1413 * Scores greater than this are placed on the normal timeshare queue
1414 * where the priority is partially decided by the most recent cpu
1415 * utilization and the rest is decided by nice value.
1416 *
1417 * The nice value of the process has a linear effect on the calculated
1418 * score. Negative nice values make it easier for a thread to be
1419 * considered interactive.
1420 */
1421 score = imax(0, sched_interact_score(td) + td->td_proc->p_nice);
1422 if (score < sched_interact) {
1423 pri = PRI_MIN_INTERACT;
1424 pri += ((PRI_MAX_INTERACT - PRI_MIN_INTERACT + 1) /
1425 sched_interact) * score;
1426 KASSERT(pri >= PRI_MIN_INTERACT && pri <= PRI_MAX_INTERACT,
1427 ("sched_priority: invalid interactive priority %d score %d",
1428 pri, score));
1429 } else {
1430 pri = SCHED_PRI_MIN;
1431 if (td->td_sched->ts_ticks)
1432 pri += SCHED_PRI_TICKS(td->td_sched);
1433 pri += SCHED_PRI_NICE(td->td_proc->p_nice);
1434 KASSERT(pri >= PRI_MIN_BATCH && pri <= PRI_MAX_BATCH,
1435 ("sched_priority: invalid priority %d: nice %d, "
1436 "ticks %d ftick %d ltick %d tick pri %d",
1437 pri, td->td_proc->p_nice, td->td_sched->ts_ticks,
1438 td->td_sched->ts_ftick, td->td_sched->ts_ltick,
1439 SCHED_PRI_TICKS(td->td_sched)));
1440 }
1441 sched_user_prio(td, pri);
1442
1443 return;
1444 }
1445
1446 /*
1447 * This routine enforces a maximum limit on the amount of scheduling history
1448 * kept. It is called after either the slptime or runtime is adjusted. This
1449 * function is ugly due to integer math.
1450 */
1451 static void
1452 sched_interact_update(struct thread *td)
1453 {
1454 struct td_sched *ts;
1455 u_int sum;
1456
1457 ts = td->td_sched;
1458 sum = ts->ts_runtime + ts->ts_slptime;
1459 if (sum < SCHED_SLP_RUN_MAX)
1460 return;
1461 /*
1462 * This only happens from two places:
1463 * 1) We have added an unusual amount of run time from fork_exit.
1464 * 2) We have added an unusual amount of sleep time from sched_sleep().
1465 */
1466 if (sum > SCHED_SLP_RUN_MAX * 2) {
1467 if (ts->ts_runtime > ts->ts_slptime) {
1468 ts->ts_runtime = SCHED_SLP_RUN_MAX;
1469 ts->ts_slptime = 1;
1470 } else {
1471 ts->ts_slptime = SCHED_SLP_RUN_MAX;
1472 ts->ts_runtime = 1;
1473 }
1474 return;
1475 }
1476 /*
1477 * If we have exceeded by more than 1/5th then the algorithm below
1478 * will not bring us back into range. Dividing by two here forces
1479 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX]
1480 */
1481 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) {
1482 ts->ts_runtime /= 2;
1483 ts->ts_slptime /= 2;
1484 return;
1485 }
1486 ts->ts_runtime = (ts->ts_runtime / 5) * 4;
1487 ts->ts_slptime = (ts->ts_slptime / 5) * 4;
1488 }
1489
1490 /*
1491 * Scale back the interactivity history when a child thread is created. The
1492 * history is inherited from the parent but the thread may behave totally
1493 * differently. For example, a shell spawning a compiler process. We want
1494 * to learn that the compiler is behaving badly very quickly.
1495 */
1496 static void
1497 sched_interact_fork(struct thread *td)
1498 {
1499 int ratio;
1500 int sum;
1501
1502 sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime;
1503 if (sum > SCHED_SLP_RUN_FORK) {
1504 ratio = sum / SCHED_SLP_RUN_FORK;
1505 td->td_sched->ts_runtime /= ratio;
1506 td->td_sched->ts_slptime /= ratio;
1507 }
1508 }
1509
1510 /*
1511 * Called from proc0_init() to setup the scheduler fields.
1512 */
1513 void
1514 schedinit(void)
1515 {
1516
1517 /*
1518 * Set up the scheduler specific parts of proc0.
1519 */
1520 proc0.p_sched = NULL; /* XXX */
1521 thread0.td_sched = &td_sched0;
1522 td_sched0.ts_ltick = ticks;
1523 td_sched0.ts_ftick = ticks;
1524 td_sched0.ts_slice = sched_slice;
1525 }
1526
1527 /*
1528 * This is only somewhat accurate since given many processes of the same
1529 * priority they will switch when their slices run out, which will be
1530 * at most sched_slice stathz ticks.
1531 */
1532 int
1533 sched_rr_interval(void)
1534 {
1535
1536 /* Convert sched_slice to hz */
1537 return (hz/(realstathz/sched_slice));
1538 }
1539
1540 /*
1541 * Update the percent cpu tracking information when it is requested or
1542 * the total history exceeds the maximum. We keep a sliding history of
1543 * tick counts that slowly decays. This is less precise than the 4BSD
1544 * mechanism since it happens with less regular and frequent events.
1545 */
1546 static void
1547 sched_pctcpu_update(struct td_sched *ts)
1548 {
1549
1550 if (ts->ts_ticks == 0)
1551 return;
1552 if (ticks - (hz / 10) < ts->ts_ltick &&
1553 SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX)
1554 return;
1555 /*
1556 * Adjust counters and watermark for pctcpu calc.
1557 */
1558 if (ts->ts_ltick > ticks - SCHED_TICK_TARG)
1559 ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) *
1560 SCHED_TICK_TARG;
1561 else
1562 ts->ts_ticks = 0;
1563 ts->ts_ltick = ticks;
1564 ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG;
1565 }
1566
1567 /*
1568 * Adjust the priority of a thread. Move it to the appropriate run-queue
1569 * if necessary. This is the back-end for several priority related
1570 * functions.
1571 */
1572 static void
1573 sched_thread_priority(struct thread *td, u_char prio)
1574 {
1575 struct td_sched *ts;
1576 struct tdq *tdq;
1577 int oldpri;
1578
1579 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio",
1580 "prio:%d", td->td_priority, "new prio:%d", prio,
1581 KTR_ATTR_LINKED, sched_tdname(curthread));
1582 if (td != curthread && prio > td->td_priority) {
1583 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread),
1584 "lend prio", "prio:%d", td->td_priority, "new prio:%d",
1585 prio, KTR_ATTR_LINKED, sched_tdname(td));
1586 }
1587 ts = td->td_sched;
1588 THREAD_LOCK_ASSERT(td, MA_OWNED);
1589 if (td->td_priority == prio)
1590 return;
1591 /*
1592 * If the priority has been elevated due to priority
1593 * propagation, we may have to move ourselves to a new
1594 * queue. This could be optimized to not re-add in some
1595 * cases.
1596 */
1597 if (TD_ON_RUNQ(td) && prio < td->td_priority) {
1598 sched_rem(td);
1599 td->td_priority = prio;
1600 sched_add(td, SRQ_BORROWING);
1601 return;
1602 }
1603 /*
1604 * If the thread is currently running we may have to adjust the lowpri
1605 * information so other cpus are aware of our current priority.
1606 */
1607 if (TD_IS_RUNNING(td)) {
1608 tdq = TDQ_CPU(ts->ts_cpu);
1609 oldpri = td->td_priority;
1610 td->td_priority = prio;
1611 if (prio < tdq->tdq_lowpri)
1612 tdq->tdq_lowpri = prio;
1613 else if (tdq->tdq_lowpri == oldpri)
1614 tdq_setlowpri(tdq, td);
1615 return;
1616 }
1617 td->td_priority = prio;
1618 }
1619
1620 /*
1621 * Update a thread's priority when it is lent another thread's
1622 * priority.
1623 */
1624 void
1625 sched_lend_prio(struct thread *td, u_char prio)
1626 {
1627
1628 td->td_flags |= TDF_BORROWING;
1629 sched_thread_priority(td, prio);
1630 }
1631
1632 /*
1633 * Restore a thread's priority when priority propagation is
1634 * over. The prio argument is the minimum priority the thread
1635 * needs to have to satisfy other possible priority lending
1636 * requests. If the thread's regular priority is less
1637 * important than prio, the thread will keep a priority boost
1638 * of prio.
1639 */
1640 void
1641 sched_unlend_prio(struct thread *td, u_char prio)
1642 {
1643 u_char base_pri;
1644
1645 if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
1646 td->td_base_pri <= PRI_MAX_TIMESHARE)
1647 base_pri = td->td_user_pri;
1648 else
1649 base_pri = td->td_base_pri;
1650 if (prio >= base_pri) {
1651 td->td_flags &= ~TDF_BORROWING;
1652 sched_thread_priority(td, base_pri);
1653 } else
1654 sched_lend_prio(td, prio);
1655 }
1656
1657 /*
1658 * Standard entry for setting the priority to an absolute value.
1659 */
1660 void
1661 sched_prio(struct thread *td, u_char prio)
1662 {
1663 u_char oldprio;
1664
1665 /* First, update the base priority. */
1666 td->td_base_pri = prio;
1667
1668 /*
1669 * If the thread is borrowing another thread's priority, don't
1670 * ever lower the priority.
1671 */
1672 if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
1673 return;
1674
1675 /* Change the real priority. */
1676 oldprio = td->td_priority;
1677 sched_thread_priority(td, prio);
1678
1679 /*
1680 * If the thread is on a turnstile, then let the turnstile update
1681 * its state.
1682 */
1683 if (TD_ON_LOCK(td) && oldprio != prio)
1684 turnstile_adjust(td, oldprio);
1685 }
1686
1687 /*
1688 * Set the base user priority, does not effect current running priority.
1689 */
1690 void
1691 sched_user_prio(struct thread *td, u_char prio)
1692 {
1693
1694 td->td_base_user_pri = prio;
1695 if (td->td_lend_user_pri <= prio)
1696 return;
1697 td->td_user_pri = prio;
1698 }
1699
1700 void
1701 sched_lend_user_prio(struct thread *td, u_char prio)
1702 {
1703
1704 THREAD_LOCK_ASSERT(td, MA_OWNED);
1705 td->td_lend_user_pri = prio;
1706 td->td_user_pri = min(prio, td->td_base_user_pri);
1707 if (td->td_priority > td->td_user_pri)
1708 sched_prio(td, td->td_user_pri);
1709 else if (td->td_priority != td->td_user_pri)
1710 td->td_flags |= TDF_NEEDRESCHED;
1711 }
1712
1713 /*
1714 * Handle migration from sched_switch(). This happens only for
1715 * cpu binding.
1716 */
1717 static struct mtx *
1718 sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags)
1719 {
1720 struct tdq *tdn;
1721
1722 tdn = TDQ_CPU(td->td_sched->ts_cpu);
1723 #ifdef SMP
1724 tdq_load_rem(tdq, td);
1725 /*
1726 * Do the lock dance required to avoid LOR. We grab an extra
1727 * spinlock nesting to prevent preemption while we're
1728 * not holding either run-queue lock.
1729 */
1730 spinlock_enter();
1731 thread_lock_block(td); /* This releases the lock on tdq. */
1732
1733 /*
1734 * Acquire both run-queue locks before placing the thread on the new
1735 * run-queue to avoid deadlocks created by placing a thread with a
1736 * blocked lock on the run-queue of a remote processor. The deadlock
1737 * occurs when a third processor attempts to lock the two queues in
1738 * question while the target processor is spinning with its own
1739 * run-queue lock held while waiting for the blocked lock to clear.
1740 */
1741 tdq_lock_pair(tdn, tdq);
1742 tdq_add(tdn, td, flags);
1743 tdq_notify(tdn, td);
1744 TDQ_UNLOCK(tdn);
1745 spinlock_exit();
1746 #endif
1747 return (TDQ_LOCKPTR(tdn));
1748 }
1749
1750 /*
1751 * Variadic version of thread_lock_unblock() that does not assume td_lock
1752 * is blocked.
1753 */
1754 static inline void
1755 thread_unblock_switch(struct thread *td, struct mtx *mtx)
1756 {
1757 atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock,
1758 (uintptr_t)mtx);
1759 }
1760
1761 /*
1762 * Switch threads. This function has to handle threads coming in while
1763 * blocked for some reason, running, or idle. It also must deal with
1764 * migrating a thread from one queue to another as running threads may
1765 * be assigned elsewhere via binding.
1766 */
1767 void
1768 sched_switch(struct thread *td, struct thread *newtd, int flags)
1769 {
1770 struct tdq *tdq;
1771 struct td_sched *ts;
1772 struct mtx *mtx;
1773 int srqflag;
1774 int cpuid;
1775
1776 THREAD_LOCK_ASSERT(td, MA_OWNED);
1777 KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument"));
1778
1779 cpuid = PCPU_GET(cpuid);
1780 tdq = TDQ_CPU(cpuid);
1781 ts = td->td_sched;
1782 mtx = td->td_lock;
1783 ts->ts_rltick = ticks;
1784 td->td_lastcpu = td->td_oncpu;
1785 td->td_oncpu = NOCPU;
1786 if (!(flags & SW_PREEMPT))
1787 td->td_flags &= ~TDF_NEEDRESCHED;
1788 td->td_owepreempt = 0;
1789 tdq->tdq_switchcnt++;
1790 /*
1791 * The lock pointer in an idle thread should never change. Reset it
1792 * to CAN_RUN as well.
1793 */
1794 if (TD_IS_IDLETHREAD(td)) {
1795 MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1796 TD_SET_CAN_RUN(td);
1797 } else if (TD_IS_RUNNING(td)) {
1798 MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1799 srqflag = (flags & SW_PREEMPT) ?
1800 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
1801 SRQ_OURSELF|SRQ_YIELDING;
1802 #ifdef SMP
1803 if (THREAD_CAN_MIGRATE(td) && !THREAD_CAN_SCHED(td, ts->ts_cpu))
1804 ts->ts_cpu = sched_pickcpu(td, 0);
1805 #endif
1806 if (ts->ts_cpu == cpuid)
1807 tdq_runq_add(tdq, td, srqflag);
1808 else {
1809 KASSERT(THREAD_CAN_MIGRATE(td) ||
1810 (ts->ts_flags & TSF_BOUND) != 0,
1811 ("Thread %p shouldn't migrate", td));
1812 mtx = sched_switch_migrate(tdq, td, srqflag);
1813 }
1814 } else {
1815 /* This thread must be going to sleep. */
1816 TDQ_LOCK(tdq);
1817 mtx = thread_lock_block(td);
1818 tdq_load_rem(tdq, td);
1819 }
1820 /*
1821 * We enter here with the thread blocked and assigned to the
1822 * appropriate cpu run-queue or sleep-queue and with the current
1823 * thread-queue locked.
1824 */
1825 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
1826 newtd = choosethread();
1827 /*
1828 * Call the MD code to switch contexts if necessary.
1829 */
1830 if (td != newtd) {
1831 #ifdef HWPMC_HOOKS
1832 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1833 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
1834 #endif
1835 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
1836 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
1837
1838 #ifdef KDTRACE_HOOKS
1839 /*
1840 * If DTrace has set the active vtime enum to anything
1841 * other than INACTIVE (0), then it should have set the
1842 * function to call.
1843 */
1844 if (dtrace_vtime_active)
1845 (*dtrace_vtime_switch_func)(newtd);
1846 #endif
1847
1848 cpu_switch(td, newtd, mtx);
1849 /*
1850 * We may return from cpu_switch on a different cpu. However,
1851 * we always return with td_lock pointing to the current cpu's
1852 * run queue lock.
1853 */
1854 cpuid = PCPU_GET(cpuid);
1855 tdq = TDQ_CPU(cpuid);
1856 lock_profile_obtain_lock_success(
1857 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
1858 #ifdef HWPMC_HOOKS
1859 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1860 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
1861 #endif
1862 } else
1863 thread_unblock_switch(td, mtx);
1864 /*
1865 * Assert that all went well and return.
1866 */
1867 TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED);
1868 MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
1869 td->td_oncpu = cpuid;
1870 }
1871
1872 /*
1873 * Adjust thread priorities as a result of a nice request.
1874 */
1875 void
1876 sched_nice(struct proc *p, int nice)
1877 {
1878 struct thread *td;
1879
1880 PROC_LOCK_ASSERT(p, MA_OWNED);
1881
1882 p->p_nice = nice;
1883 FOREACH_THREAD_IN_PROC(p, td) {
1884 thread_lock(td);
1885 sched_priority(td);
1886 sched_prio(td, td->td_base_user_pri);
1887 thread_unlock(td);
1888 }
1889 }
1890
1891 /*
1892 * Record the sleep time for the interactivity scorer.
1893 */
1894 void
1895 sched_sleep(struct thread *td, int prio)
1896 {
1897
1898 THREAD_LOCK_ASSERT(td, MA_OWNED);
1899
1900 td->td_slptick = ticks;
1901 if (TD_IS_SUSPENDED(td) || prio >= PSOCK)
1902 td->td_flags |= TDF_CANSWAP;
1903 if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
1904 return;
1905 if (static_boost == 1 && prio)
1906 sched_prio(td, prio);
1907 else if (static_boost && td->td_priority > static_boost)
1908 sched_prio(td, static_boost);
1909 }
1910
1911 /*
1912 * Schedule a thread to resume execution and record how long it voluntarily
1913 * slept. We also update the pctcpu, interactivity, and priority.
1914 */
1915 void
1916 sched_wakeup(struct thread *td)
1917 {
1918 struct td_sched *ts;
1919 int slptick;
1920
1921 THREAD_LOCK_ASSERT(td, MA_OWNED);
1922 ts = td->td_sched;
1923 td->td_flags &= ~TDF_CANSWAP;
1924 /*
1925 * If we slept for more than a tick update our interactivity and
1926 * priority.
1927 */
1928 slptick = td->td_slptick;
1929 td->td_slptick = 0;
1930 if (slptick && slptick != ticks) {
1931 u_int hzticks;
1932
1933 hzticks = (ticks - slptick) << SCHED_TICK_SHIFT;
1934 ts->ts_slptime += hzticks;
1935 sched_interact_update(td);
1936 sched_pctcpu_update(ts);
1937 }
1938 /* Reset the slice value after we sleep. */
1939 ts->ts_slice = sched_slice;
1940 sched_add(td, SRQ_BORING);
1941 }
1942
1943 /*
1944 * Penalize the parent for creating a new child and initialize the child's
1945 * priority.
1946 */
1947 void
1948 sched_fork(struct thread *td, struct thread *child)
1949 {
1950 THREAD_LOCK_ASSERT(td, MA_OWNED);
1951 sched_fork_thread(td, child);
1952 /*
1953 * Penalize the parent and child for forking.
1954 */
1955 sched_interact_fork(child);
1956 sched_priority(child);
1957 td->td_sched->ts_runtime += tickincr;
1958 sched_interact_update(td);
1959 sched_priority(td);
1960 }
1961
1962 /*
1963 * Fork a new thread, may be within the same process.
1964 */
1965 void
1966 sched_fork_thread(struct thread *td, struct thread *child)
1967 {
1968 struct td_sched *ts;
1969 struct td_sched *ts2;
1970
1971 THREAD_LOCK_ASSERT(td, MA_OWNED);
1972 /*
1973 * Initialize child.
1974 */
1975 ts = td->td_sched;
1976 ts2 = child->td_sched;
1977 child->td_lock = TDQ_LOCKPTR(TDQ_SELF());
1978 child->td_cpuset = cpuset_ref(td->td_cpuset);
1979 ts2->ts_cpu = ts->ts_cpu;
1980 ts2->ts_flags = 0;
1981 /*
1982 * Grab our parents cpu estimation information.
1983 */
1984 ts2->ts_ticks = ts->ts_ticks;
1985 ts2->ts_ltick = ts->ts_ltick;
1986 ts2->ts_incrtick = ts->ts_incrtick;
1987 ts2->ts_ftick = ts->ts_ftick;
1988 /*
1989 * Do not inherit any borrowed priority from the parent.
1990 */
1991 child->td_priority = child->td_base_pri;
1992 /*
1993 * And update interactivity score.
1994 */
1995 ts2->ts_slptime = ts->ts_slptime;
1996 ts2->ts_runtime = ts->ts_runtime;
1997 ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */
1998 #ifdef KTR
1999 bzero(ts2->ts_name, sizeof(ts2->ts_name));
2000 #endif
2001 }
2002
2003 /*
2004 * Adjust the priority class of a thread.
2005 */
2006 void
2007 sched_class(struct thread *td, int class)
2008 {
2009
2010 THREAD_LOCK_ASSERT(td, MA_OWNED);
2011 if (td->td_pri_class == class)
2012 return;
2013 td->td_pri_class = class;
2014 }
2015
2016 /*
2017 * Return some of the child's priority and interactivity to the parent.
2018 */
2019 void
2020 sched_exit(struct proc *p, struct thread *child)
2021 {
2022 struct thread *td;
2023
2024 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit",
2025 "prio:%d", child->td_priority);
2026 PROC_LOCK_ASSERT(p, MA_OWNED);
2027 td = FIRST_THREAD_IN_PROC(p);
2028 sched_exit_thread(td, child);
2029 }
2030
2031 /*
2032 * Penalize another thread for the time spent on this one. This helps to
2033 * worsen the priority and interactivity of processes which schedule batch
2034 * jobs such as make. This has little effect on the make process itself but
2035 * causes new processes spawned by it to receive worse scores immediately.
2036 */
2037 void
2038 sched_exit_thread(struct thread *td, struct thread *child)
2039 {
2040
2041 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit",
2042 "prio:%d", child->td_priority);
2043 /*
2044 * Give the child's runtime to the parent without returning the
2045 * sleep time as a penalty to the parent. This causes shells that
2046 * launch expensive things to mark their children as expensive.
2047 */
2048 thread_lock(td);
2049 td->td_sched->ts_runtime += child->td_sched->ts_runtime;
2050 sched_interact_update(td);
2051 sched_priority(td);
2052 thread_unlock(td);
2053 }
2054
2055 void
2056 sched_preempt(struct thread *td)
2057 {
2058 struct tdq *tdq;
2059
2060 thread_lock(td);
2061 tdq = TDQ_SELF();
2062 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2063 tdq->tdq_ipipending = 0;
2064 if (td->td_priority > tdq->tdq_lowpri) {
2065 int flags;
2066
2067 flags = SW_INVOL | SW_PREEMPT;
2068 if (td->td_critnest > 1)
2069 td->td_owepreempt = 1;
2070 else if (TD_IS_IDLETHREAD(td))
2071 mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL);
2072 else
2073 mi_switch(flags | SWT_REMOTEPREEMPT, NULL);
2074 }
2075 thread_unlock(td);
2076 }
2077
2078 /*
2079 * Fix priorities on return to user-space. Priorities may be elevated due
2080 * to static priorities in msleep() or similar.
2081 */
2082 void
2083 sched_userret(struct thread *td)
2084 {
2085 /*
2086 * XXX we cheat slightly on the locking here to avoid locking in
2087 * the usual case. Setting td_priority here is essentially an
2088 * incomplete workaround for not setting it properly elsewhere.
2089 * Now that some interrupt handlers are threads, not setting it
2090 * properly elsewhere can clobber it in the window between setting
2091 * it here and returning to user mode, so don't waste time setting
2092 * it perfectly here.
2093 */
2094 KASSERT((td->td_flags & TDF_BORROWING) == 0,
2095 ("thread with borrowed priority returning to userland"));
2096 if (td->td_priority != td->td_user_pri) {
2097 thread_lock(td);
2098 td->td_priority = td->td_user_pri;
2099 td->td_base_pri = td->td_user_pri;
2100 tdq_setlowpri(TDQ_SELF(), td);
2101 thread_unlock(td);
2102 }
2103 }
2104
2105 /*
2106 * Handle a stathz tick. This is really only relevant for timeshare
2107 * threads.
2108 */
2109 void
2110 sched_clock(struct thread *td)
2111 {
2112 struct tdq *tdq;
2113 struct td_sched *ts;
2114
2115 THREAD_LOCK_ASSERT(td, MA_OWNED);
2116 tdq = TDQ_SELF();
2117 #ifdef SMP
2118 /*
2119 * We run the long term load balancer infrequently on the first cpu.
2120 */
2121 if (balance_tdq == tdq) {
2122 if (balance_ticks && --balance_ticks == 0)
2123 sched_balance();
2124 }
2125 #endif
2126 /*
2127 * Save the old switch count so we have a record of the last ticks
2128 * activity. Initialize the new switch count based on our load.
2129 * If there is some activity seed it to reflect that.
2130 */
2131 tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt;
2132 tdq->tdq_switchcnt = tdq->tdq_load;
2133 /*
2134 * Advance the insert index once for each tick to ensure that all
2135 * threads get a chance to run.
2136 */
2137 if (tdq->tdq_idx == tdq->tdq_ridx) {
2138 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS;
2139 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx]))
2140 tdq->tdq_ridx = tdq->tdq_idx;
2141 }
2142 ts = td->td_sched;
2143 if (td->td_pri_class & PRI_FIFO_BIT)
2144 return;
2145 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) {
2146 /*
2147 * We used a tick; charge it to the thread so
2148 * that we can compute our interactivity.
2149 */
2150 td->td_sched->ts_runtime += tickincr;
2151 sched_interact_update(td);
2152 sched_priority(td);
2153 }
2154 /*
2155 * We used up one time slice.
2156 */
2157 if (--ts->ts_slice > 0)
2158 return;
2159 /*
2160 * We're out of time, force a requeue at userret().
2161 */
2162 ts->ts_slice = sched_slice;
2163 td->td_flags |= TDF_NEEDRESCHED;
2164 }
2165
2166 /*
2167 * Called once per hz tick. Used for cpu utilization information. This
2168 * is easier than trying to scale based on stathz.
2169 */
2170 void
2171 sched_tick(int cnt)
2172 {
2173 struct td_sched *ts;
2174
2175 ts = curthread->td_sched;
2176 /*
2177 * Ticks is updated asynchronously on a single cpu. Check here to
2178 * avoid incrementing ts_ticks multiple times in a single tick.
2179 */
2180 if (ts->ts_incrtick == ticks)
2181 return;
2182 /* Adjust ticks for pctcpu */
2183 ts->ts_ticks += cnt << SCHED_TICK_SHIFT;
2184 ts->ts_ltick = ticks;
2185 ts->ts_incrtick = ticks;
2186 /*
2187 * Update if we've exceeded our desired tick threshold by over one
2188 * second.
2189 */
2190 if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick)
2191 sched_pctcpu_update(ts);
2192 }
2193
2194 /*
2195 * Return whether the current CPU has runnable tasks. Used for in-kernel
2196 * cooperative idle threads.
2197 */
2198 int
2199 sched_runnable(void)
2200 {
2201 struct tdq *tdq;
2202 int load;
2203
2204 load = 1;
2205
2206 tdq = TDQ_SELF();
2207 if ((curthread->td_flags & TDF_IDLETD) != 0) {
2208 if (tdq->tdq_load > 0)
2209 goto out;
2210 } else
2211 if (tdq->tdq_load - 1 > 0)
2212 goto out;
2213 load = 0;
2214 out:
2215 return (load);
2216 }
2217
2218 /*
2219 * Choose the highest priority thread to run. The thread is removed from
2220 * the run-queue while running however the load remains. For SMP we set
2221 * the tdq in the global idle bitmask if it idles here.
2222 */
2223 struct thread *
2224 sched_choose(void)
2225 {
2226 struct thread *td;
2227 struct tdq *tdq;
2228
2229 tdq = TDQ_SELF();
2230 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2231 td = tdq_choose(tdq);
2232 if (td) {
2233 td->td_sched->ts_ltick = ticks;
2234 tdq_runq_rem(tdq, td);
2235 tdq->tdq_lowpri = td->td_priority;
2236 return (td);
2237 }
2238 tdq->tdq_lowpri = PRI_MAX_IDLE;
2239 return (PCPU_GET(idlethread));
2240 }
2241
2242 /*
2243 * Set owepreempt if necessary. Preemption never happens directly in ULE,
2244 * we always request it once we exit a critical section.
2245 */
2246 static inline void
2247 sched_setpreempt(struct thread *td)
2248 {
2249 struct thread *ctd;
2250 int cpri;
2251 int pri;
2252
2253 THREAD_LOCK_ASSERT(curthread, MA_OWNED);
2254
2255 ctd = curthread;
2256 pri = td->td_priority;
2257 cpri = ctd->td_priority;
2258 if (pri < cpri)
2259 ctd->td_flags |= TDF_NEEDRESCHED;
2260 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd))
2261 return;
2262 if (!sched_shouldpreempt(pri, cpri, 0))
2263 return;
2264 ctd->td_owepreempt = 1;
2265 }
2266
2267 /*
2268 * Add a thread to a thread queue. Select the appropriate runq and add the
2269 * thread to it. This is the internal function called when the tdq is
2270 * predetermined.
2271 */
2272 void
2273 tdq_add(struct tdq *tdq, struct thread *td, int flags)
2274 {
2275
2276 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2277 KASSERT((td->td_inhibitors == 0),
2278 ("sched_add: trying to run inhibited thread"));
2279 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
2280 ("sched_add: bad thread state"));
2281 KASSERT(td->td_flags & TDF_INMEM,
2282 ("sched_add: thread swapped out"));
2283
2284 if (td->td_priority < tdq->tdq_lowpri)
2285 tdq->tdq_lowpri = td->td_priority;
2286 tdq_runq_add(tdq, td, flags);
2287 tdq_load_add(tdq, td);
2288 }
2289
2290 /*
2291 * Select the target thread queue and add a thread to it. Request
2292 * preemption or IPI a remote processor if required.
2293 */
2294 void
2295 sched_add(struct thread *td, int flags)
2296 {
2297 struct tdq *tdq;
2298 #ifdef SMP
2299 int cpu;
2300 #endif
2301
2302 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
2303 "prio:%d", td->td_priority, KTR_ATTR_LINKED,
2304 sched_tdname(curthread));
2305 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
2306 KTR_ATTR_LINKED, sched_tdname(td));
2307 THREAD_LOCK_ASSERT(td, MA_OWNED);
2308 /*
2309 * Recalculate the priority before we select the target cpu or
2310 * run-queue.
2311 */
2312 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
2313 sched_priority(td);
2314 #ifdef SMP
2315 /*
2316 * Pick the destination cpu and if it isn't ours transfer to the
2317 * target cpu.
2318 */
2319 cpu = sched_pickcpu(td, flags);
2320 tdq = sched_setcpu(td, cpu, flags);
2321 tdq_add(tdq, td, flags);
2322 if (cpu != PCPU_GET(cpuid)) {
2323 tdq_notify(tdq, td);
2324 return;
2325 }
2326 #else
2327 tdq = TDQ_SELF();
2328 TDQ_LOCK(tdq);
2329 /*
2330 * Now that the thread is moving to the run-queue, set the lock
2331 * to the scheduler's lock.
2332 */
2333 thread_lock_set(td, TDQ_LOCKPTR(tdq));
2334 tdq_add(tdq, td, flags);
2335 #endif
2336 if (!(flags & SRQ_YIELDING))
2337 sched_setpreempt(td);
2338 }
2339
2340 /*
2341 * Remove a thread from a run-queue without running it. This is used
2342 * when we're stealing a thread from a remote queue. Otherwise all threads
2343 * exit by calling sched_exit_thread() and sched_throw() themselves.
2344 */
2345 void
2346 sched_rem(struct thread *td)
2347 {
2348 struct tdq *tdq;
2349
2350 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem",
2351 "prio:%d", td->td_priority);
2352 tdq = TDQ_CPU(td->td_sched->ts_cpu);
2353 TDQ_LOCK_ASSERT(tdq, MA_OWNED);
2354 MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2355 KASSERT(TD_ON_RUNQ(td),
2356 ("sched_rem: thread not on run queue"));
2357 tdq_runq_rem(tdq, td);
2358 tdq_load_rem(tdq, td);
2359 TD_SET_CAN_RUN(td);
2360 if (td->td_priority == tdq->tdq_lowpri)
2361 tdq_setlowpri(tdq, NULL);
2362 }
2363
2364 /*
2365 * Fetch cpu utilization information. Updates on demand.
2366 */
2367 fixpt_t
2368 sched_pctcpu(struct thread *td)
2369 {
2370 fixpt_t pctcpu;
2371 struct td_sched *ts;
2372
2373 pctcpu = 0;
2374 ts = td->td_sched;
2375 if (ts == NULL)
2376 return (0);
2377
2378 THREAD_LOCK_ASSERT(td, MA_OWNED);
2379 if (ts->ts_ticks) {
2380 int rtick;
2381
2382 sched_pctcpu_update(ts);
2383 /* How many rtick per second ? */
2384 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz);
2385 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT;
2386 }
2387
2388 return (pctcpu);
2389 }
2390
2391 /*
2392 * Enforce affinity settings for a thread. Called after adjustments to
2393 * cpumask.
2394 */
2395 void
2396 sched_affinity(struct thread *td)
2397 {
2398 #ifdef SMP
2399 struct td_sched *ts;
2400
2401 THREAD_LOCK_ASSERT(td, MA_OWNED);
2402 ts = td->td_sched;
2403 if (THREAD_CAN_SCHED(td, ts->ts_cpu))
2404 return;
2405 if (TD_ON_RUNQ(td)) {
2406 sched_rem(td);
2407 sched_add(td, SRQ_BORING);
2408 return;
2409 }
2410 if (!TD_IS_RUNNING(td))
2411 return;
2412 /*
2413 * Force a switch before returning to userspace. If the
2414 * target thread is not running locally send an ipi to force
2415 * the issue.
2416 */
2417 td->td_flags |= TDF_NEEDRESCHED;
2418 if (td != curthread)
2419 ipi_cpu(ts->ts_cpu, IPI_PREEMPT);
2420 #endif
2421 }
2422
2423 /*
2424 * Bind a thread to a target cpu.
2425 */
2426 void
2427 sched_bind(struct thread *td, int cpu)
2428 {
2429 struct td_sched *ts;
2430
2431 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED);
2432 KASSERT(td == curthread, ("sched_bind: can only bind curthread"));
2433 ts = td->td_sched;
2434 if (ts->ts_flags & TSF_BOUND)
2435 sched_unbind(td);
2436 KASSERT(THREAD_CAN_MIGRATE(td), ("%p must be migratable", td));
2437 ts->ts_flags |= TSF_BOUND;
2438 sched_pin();
2439 if (PCPU_GET(cpuid) == cpu)
2440 return;
2441 ts->ts_cpu = cpu;
2442 /* When we return from mi_switch we'll be on the correct cpu. */
2443 mi_switch(SW_VOL, NULL);
2444 }
2445
2446 /*
2447 * Release a bound thread.
2448 */
2449 void
2450 sched_unbind(struct thread *td)
2451 {
2452 struct td_sched *ts;
2453
2454 THREAD_LOCK_ASSERT(td, MA_OWNED);
2455 KASSERT(td == curthread, ("sched_unbind: can only bind curthread"));
2456 ts = td->td_sched;
2457 if ((ts->ts_flags & TSF_BOUND) == 0)
2458 return;
2459 ts->ts_flags &= ~TSF_BOUND;
2460 sched_unpin();
2461 }
2462
2463 int
2464 sched_is_bound(struct thread *td)
2465 {
2466 THREAD_LOCK_ASSERT(td, MA_OWNED);
2467 return (td->td_sched->ts_flags & TSF_BOUND);
2468 }
2469
2470 /*
2471 * Basic yield call.
2472 */
2473 void
2474 sched_relinquish(struct thread *td)
2475 {
2476 thread_lock(td);
2477 mi_switch(SW_VOL | SWT_RELINQUISH, NULL);
2478 thread_unlock(td);
2479 }
2480
2481 /*
2482 * Return the total system load.
2483 */
2484 int
2485 sched_load(void)
2486 {
2487 #ifdef SMP
2488 int total;
2489 int i;
2490
2491 total = 0;
2492 CPU_FOREACH(i)
2493 total += TDQ_CPU(i)->tdq_sysload;
2494 return (total);
2495 #else
2496 return (TDQ_SELF()->tdq_sysload);
2497 #endif
2498 }
2499
2500 int
2501 sched_sizeof_proc(void)
2502 {
2503 return (sizeof(struct proc));
2504 }
2505
2506 int
2507 sched_sizeof_thread(void)
2508 {
2509 return (sizeof(struct thread) + sizeof(struct td_sched));
2510 }
2511
2512 #ifdef SMP
2513 #define TDQ_IDLESPIN(tdq) \
2514 ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0)
2515 #else
2516 #define TDQ_IDLESPIN(tdq) 1
2517 #endif
2518
2519 /*
2520 * The actual idle process.
2521 */
2522 void
2523 sched_idletd(void *dummy)
2524 {
2525 struct thread *td;
2526 struct tdq *tdq;
2527 int switchcnt;
2528 int i;
2529
2530 mtx_assert(&Giant, MA_NOTOWNED);
2531 td = curthread;
2532 tdq = TDQ_SELF();
2533 for (;;) {
2534 #ifdef SMP
2535 if (tdq_idled(tdq) == 0)
2536 continue;
2537 #endif
2538 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2539 /*
2540 * If we're switching very frequently, spin while checking
2541 * for load rather than entering a low power state that
2542 * may require an IPI. However, don't do any busy
2543 * loops while on SMT machines as this simply steals
2544 * cycles from cores doing useful work.
2545 */
2546 if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) {
2547 for (i = 0; i < sched_idlespins; i++) {
2548 if (tdq->tdq_load)
2549 break;
2550 cpu_spinwait();
2551 }
2552 }
2553 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
2554 if (tdq->tdq_load == 0) {
2555 tdq->tdq_cpu_idle = 1;
2556 if (tdq->tdq_load == 0) {
2557 cpu_idle(switchcnt > sched_idlespinthresh * 4);
2558 tdq->tdq_switchcnt++;
2559 }
2560 tdq->tdq_cpu_idle = 0;
2561 }
2562 if (tdq->tdq_load) {
2563 thread_lock(td);
2564 mi_switch(SW_VOL | SWT_IDLE, NULL);
2565 thread_unlock(td);
2566 }
2567 }
2568 }
2569
2570 /*
2571 * A CPU is entering for the first time or a thread is exiting.
2572 */
2573 void
2574 sched_throw(struct thread *td)
2575 {
2576 struct thread *newtd;
2577 struct tdq *tdq;
2578
2579 tdq = TDQ_SELF();
2580 if (td == NULL) {
2581 /* Correct spinlock nesting and acquire the correct lock. */
2582 TDQ_LOCK(tdq);
2583 spinlock_exit();
2584 } else {
2585 MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2586 tdq_load_rem(tdq, td);
2587 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
2588 }
2589 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
2590 newtd = choosethread();
2591 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
2592 PCPU_SET(switchtime, cpu_ticks());
2593 PCPU_SET(switchticks, ticks);
2594 cpu_throw(td, newtd); /* doesn't return */
2595 }
2596
2597 /*
2598 * This is called from fork_exit(). Just acquire the correct locks and
2599 * let fork do the rest of the work.
2600 */
2601 void
2602 sched_fork_exit(struct thread *td)
2603 {
2604 struct td_sched *ts;
2605 struct tdq *tdq;
2606 int cpuid;
2607
2608 /*
2609 * Finish setting up thread glue so that it begins execution in a
2610 * non-nested critical section with the scheduler lock held.
2611 */
2612 cpuid = PCPU_GET(cpuid);
2613 tdq = TDQ_CPU(cpuid);
2614 ts = td->td_sched;
2615 if (TD_IS_IDLETHREAD(td))
2616 td->td_lock = TDQ_LOCKPTR(tdq);
2617 MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
2618 td->td_oncpu = cpuid;
2619 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
2620 lock_profile_obtain_lock_success(
2621 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
2622 }
2623
2624 /*
2625 * Create on first use to catch odd startup conditons.
2626 */
2627 char *
2628 sched_tdname(struct thread *td)
2629 {
2630 #ifdef KTR
2631 struct td_sched *ts;
2632
2633 ts = td->td_sched;
2634 if (ts->ts_name[0] == '\0')
2635 snprintf(ts->ts_name, sizeof(ts->ts_name),
2636 "%s tid %d", td->td_name, td->td_tid);
2637 return (ts->ts_name);
2638 #else
2639 return (td->td_name);
2640 #endif
2641 }
2642
2643 #ifdef SMP
2644
2645 /*
2646 * Build the CPU topology dump string. Is recursively called to collect
2647 * the topology tree.
2648 */
2649 static int
2650 sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg,
2651 int indent)
2652 {
2653 char cpusetbuf[CPUSETBUFSIZ];
2654 int i, first;
2655
2656 sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent,
2657 "", 1 + indent / 2, cg->cg_level);
2658 sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"%s\">", indent, "",
2659 cg->cg_count, cpusetobj_strprint(cpusetbuf, &cg->cg_mask));
2660 first = TRUE;
2661 for (i = 0; i < MAXCPU; i++) {
2662 if (CPU_ISSET(i, &cg->cg_mask)) {
2663 if (!first)
2664 sbuf_printf(sb, ", ");
2665 else
2666 first = FALSE;
2667 sbuf_printf(sb, "%d", i);
2668 }
2669 }
2670 sbuf_printf(sb, "</cpu>\n");
2671
2672 if (cg->cg_flags != 0) {
2673 sbuf_printf(sb, "%*s <flags>", indent, "");
2674 if ((cg->cg_flags & CG_FLAG_HTT) != 0)
2675 sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>");
2676 if ((cg->cg_flags & CG_FLAG_THREAD) != 0)
2677 sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>");
2678 if ((cg->cg_flags & CG_FLAG_SMT) != 0)
2679 sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>");
2680 sbuf_printf(sb, "</flags>\n");
2681 }
2682
2683 if (cg->cg_children > 0) {
2684 sbuf_printf(sb, "%*s <children>\n", indent, "");
2685 for (i = 0; i < cg->cg_children; i++)
2686 sysctl_kern_sched_topology_spec_internal(sb,
2687 &cg->cg_child[i], indent+2);
2688 sbuf_printf(sb, "%*s </children>\n", indent, "");
2689 }
2690 sbuf_printf(sb, "%*s</group>\n", indent, "");
2691 return (0);
2692 }
2693
2694 /*
2695 * Sysctl handler for retrieving topology dump. It's a wrapper for
2696 * the recursive sysctl_kern_smp_topology_spec_internal().
2697 */
2698 static int
2699 sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS)
2700 {
2701 struct sbuf *topo;
2702 int err;
2703
2704 KASSERT(cpu_top != NULL, ("cpu_top isn't initialized"));
2705
2706 topo = sbuf_new(NULL, NULL, 500, SBUF_AUTOEXTEND);
2707 if (topo == NULL)
2708 return (ENOMEM);
2709
2710 sbuf_printf(topo, "<groups>\n");
2711 err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1);
2712 sbuf_printf(topo, "</groups>\n");
2713
2714 if (err == 0) {
2715 sbuf_finish(topo);
2716 err = SYSCTL_OUT(req, sbuf_data(topo), sbuf_len(topo));
2717 }
2718 sbuf_delete(topo);
2719 return (err);
2720 }
2721
2722 #endif
2723
2724 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler");
2725 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0,
2726 "Scheduler name");
2727 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
2728 "Slice size for timeshare threads");
2729 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0,
2730 "Interactivity score threshold");
2731 SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh,
2732 0,"Min priority for preemption, lower priorities have greater precedence");
2733 SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost,
2734 0,"Controls whether static kernel priorities are assigned to sleeping threads.");
2735 SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins,
2736 0,"Number of times idle will spin waiting for new work.");
2737 SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW, &sched_idlespinthresh,
2738 0,"Threshold before we will permit idle spinning.");
2739 #ifdef SMP
2740 SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0,
2741 "Number of hz ticks to keep thread affinity for");
2742 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0,
2743 "Enables the long-term load balancer");
2744 SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW,
2745 &balance_interval, 0,
2746 "Average frequency in stathz ticks to run the long-term balancer");
2747 SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0,
2748 "Steals work from another hyper-threaded core on idle");
2749 SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0,
2750 "Attempts to steal work from other cores before idling");
2751 SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0,
2752 "Minimum load on remote cpu before we'll steal");
2753
2754 /* Retrieve SMP topology */
2755 SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING |
2756 CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A",
2757 "XML dump of detected CPU topology");
2758
2759 #endif
2760
2761 /* ps compat. All cpu percentages from ULE are weighted. */
2762 static int ccpu = 0;
2763 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
Cache object: ebf0ccdaa2a7f157c92e691dd88392fd
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