2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1982, 1986, 1990, 1991, 1993
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6 * (c) UNIX System Laboratories, Inc.
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37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include "opt_hwpmc_hooks.h"
41 #include "opt_sched.h"
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/cpuset.h>
46 #include <sys/kernel.h>
49 #include <sys/kthread.h>
50 #include <sys/mutex.h>
52 #include <sys/resourcevar.h>
53 #include <sys/sched.h>
56 #include <sys/sysctl.h>
58 #include <sys/turnstile.h>
60 #include <machine/pcb.h>
61 #include <machine/smp.h>
64 #include <sys/pmckern.h>
68 #include <sys/dtrace_bsd.h>
69 int dtrace_vtime_active;
70 dtrace_vtime_switch_func_t dtrace_vtime_switch_func;
74 * INVERSE_ESTCPU_WEIGHT is only suitable for statclock() frequencies in
75 * the range 100-256 Hz (approximately).
77 #define ESTCPULIM(e) \
78 min((e), INVERSE_ESTCPU_WEIGHT * (NICE_WEIGHT * (PRIO_MAX - PRIO_MIN) - \
79 RQ_PPQ) + INVERSE_ESTCPU_WEIGHT - 1)
81 #define INVERSE_ESTCPU_WEIGHT (8 * smp_cpus)
83 #define INVERSE_ESTCPU_WEIGHT 8 /* 1 / (priorities per estcpu level). */
85 #define NICE_WEIGHT 1 /* Priorities per nice level. */
87 #define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX)))
90 * The schedulable entity that runs a context.
91 * This is an extension to the thread structure and is tailored to
92 * the requirements of this scheduler.
93 * All fields are protected by the scheduler lock.
96 fixpt_t ts_pctcpu; /* %cpu during p_swtime. */
97 u_int ts_estcpu; /* Estimated cpu utilization. */
98 int ts_cpticks; /* Ticks of cpu time. */
99 int ts_slptime; /* Seconds !RUNNING. */
100 int ts_slice; /* Remaining part of time slice. */
102 struct runq *ts_runq; /* runq the thread is currently on */
104 char ts_name[TS_NAME_LEN];
108 /* flags kept in td_flags */
109 #define TDF_DIDRUN TDF_SCHED0 /* thread actually ran. */
110 #define TDF_BOUND TDF_SCHED1 /* Bound to one CPU. */
111 #define TDF_SLICEEND TDF_SCHED2 /* Thread time slice is over. */
113 /* flags kept in ts_flags */
114 #define TSF_AFFINITY 0x0001 /* Has a non-"full" CPU set. */
116 #define SKE_RUNQ_PCPU(ts) \
117 ((ts)->ts_runq != 0 && (ts)->ts_runq != &runq)
119 #define THREAD_CAN_SCHED(td, cpu) \
120 CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask)
122 _Static_assert(sizeof(struct thread) + sizeof(struct td_sched) <=
123 sizeof(struct thread0_storage),
124 "increase struct thread0_storage.t0st_sched size");
126 static struct mtx sched_lock;
128 static int realstathz = 127; /* stathz is sometimes 0 and run off of hz. */
129 static int sched_tdcnt; /* Total runnable threads in the system. */
130 static int sched_slice = 12; /* Thread run time before rescheduling. */
132 static void setup_runqs(void);
133 static void schedcpu(void);
134 static void schedcpu_thread(void);
135 static void sched_priority(struct thread *td, u_char prio);
136 static void sched_setup(void *dummy);
137 static void maybe_resched(struct thread *td);
138 static void updatepri(struct thread *td);
139 static void resetpriority(struct thread *td);
140 static void resetpriority_thread(struct thread *td);
142 static int sched_pickcpu(struct thread *td);
143 static int forward_wakeup(int cpunum);
144 static void kick_other_cpu(int pri, int cpuid);
147 static struct kproc_desc sched_kp = {
152 SYSINIT(schedcpu, SI_SUB_LAST, SI_ORDER_FIRST, kproc_start,
154 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
156 static void sched_initticks(void *dummy);
157 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks,
163 static struct runq runq;
169 static struct runq runq_pcpu[MAXCPU];
170 long runq_length[MAXCPU];
172 static cpuset_t idle_cpus_mask;
175 struct pcpuidlestat {
179 DPCPU_DEFINE_STATIC(struct pcpuidlestat, idlestat);
187 for (i = 0; i < MAXCPU; ++i)
188 runq_init(&runq_pcpu[i]);
195 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
197 int error, new_val, period;
199 period = 1000000 / realstathz;
200 new_val = period * sched_slice;
201 error = sysctl_handle_int(oidp, &new_val, 0, req);
202 if (error != 0 || req->newptr == NULL)
206 sched_slice = imax(1, (new_val + period / 2) / period);
207 hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
212 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RD, 0, "Scheduler");
214 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "4BSD", 0,
216 SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW,
217 NULL, 0, sysctl_kern_quantum, "I",
218 "Quantum for timeshare threads in microseconds");
219 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
220 "Quantum for timeshare threads in stathz ticks");
222 /* Enable forwarding of wakeups to all other cpus */
223 static SYSCTL_NODE(_kern_sched, OID_AUTO, ipiwakeup, CTLFLAG_RD, NULL,
226 static int runq_fuzz = 1;
227 SYSCTL_INT(_kern_sched, OID_AUTO, runq_fuzz, CTLFLAG_RW, &runq_fuzz, 0, "");
229 static int forward_wakeup_enabled = 1;
230 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, enabled, CTLFLAG_RW,
231 &forward_wakeup_enabled, 0,
232 "Forwarding of wakeup to idle CPUs");
234 static int forward_wakeups_requested = 0;
235 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, requested, CTLFLAG_RD,
236 &forward_wakeups_requested, 0,
237 "Requests for Forwarding of wakeup to idle CPUs");
239 static int forward_wakeups_delivered = 0;
240 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, delivered, CTLFLAG_RD,
241 &forward_wakeups_delivered, 0,
242 "Completed Forwarding of wakeup to idle CPUs");
244 static int forward_wakeup_use_mask = 1;
245 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, usemask, CTLFLAG_RW,
246 &forward_wakeup_use_mask, 0,
247 "Use the mask of idle cpus");
249 static int forward_wakeup_use_loop = 0;
250 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, useloop, CTLFLAG_RW,
251 &forward_wakeup_use_loop, 0,
252 "Use a loop to find idle cpus");
256 static int sched_followon = 0;
257 SYSCTL_INT(_kern_sched, OID_AUTO, followon, CTLFLAG_RW,
259 "allow threads to share a quantum");
262 SDT_PROVIDER_DEFINE(sched);
264 SDT_PROBE_DEFINE3(sched, , , change__pri, "struct thread *",
265 "struct proc *", "uint8_t");
266 SDT_PROBE_DEFINE3(sched, , , dequeue, "struct thread *",
267 "struct proc *", "void *");
268 SDT_PROBE_DEFINE4(sched, , , enqueue, "struct thread *",
269 "struct proc *", "void *", "int");
270 SDT_PROBE_DEFINE4(sched, , , lend__pri, "struct thread *",
271 "struct proc *", "uint8_t", "struct thread *");
272 SDT_PROBE_DEFINE2(sched, , , load__change, "int", "int");
273 SDT_PROBE_DEFINE2(sched, , , off__cpu, "struct thread *",
275 SDT_PROBE_DEFINE(sched, , , on__cpu);
276 SDT_PROBE_DEFINE(sched, , , remain__cpu);
277 SDT_PROBE_DEFINE2(sched, , , surrender, "struct thread *",
285 KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt);
286 SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt);
294 KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt);
295 SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt);
298 * Arrange to reschedule if necessary, taking the priorities and
299 * schedulers into account.
302 maybe_resched(struct thread *td)
305 THREAD_LOCK_ASSERT(td, MA_OWNED);
306 if (td->td_priority < curthread->td_priority)
307 curthread->td_flags |= TDF_NEEDRESCHED;
311 * This function is called when a thread is about to be put on run queue
312 * because it has been made runnable or its priority has been adjusted. It
313 * determines if the new thread should preempt the current thread. If so,
314 * it sets td_owepreempt to request a preemption.
317 maybe_preempt(struct thread *td)
324 * The new thread should not preempt the current thread if any of the
325 * following conditions are true:
327 * - The kernel is in the throes of crashing (panicstr).
328 * - The current thread has a higher (numerically lower) or
329 * equivalent priority. Note that this prevents curthread from
330 * trying to preempt to itself.
331 * - The current thread has an inhibitor set or is in the process of
332 * exiting. In this case, the current thread is about to switch
333 * out anyways, so there's no point in preempting. If we did,
334 * the current thread would not be properly resumed as well, so
335 * just avoid that whole landmine.
336 * - If the new thread's priority is not a realtime priority and
337 * the current thread's priority is not an idle priority and
338 * FULL_PREEMPTION is disabled.
340 * If all of these conditions are false, but the current thread is in
341 * a nested critical section, then we have to defer the preemption
342 * until we exit the critical section. Otherwise, switch immediately
346 THREAD_LOCK_ASSERT(td, MA_OWNED);
347 KASSERT((td->td_inhibitors == 0),
348 ("maybe_preempt: trying to run inhibited thread"));
349 pri = td->td_priority;
350 cpri = ctd->td_priority;
351 if (panicstr != NULL || pri >= cpri /* || dumping */ ||
352 TD_IS_INHIBITED(ctd))
354 #ifndef FULL_PREEMPTION
355 if (pri > PRI_MAX_ITHD && cpri < PRI_MIN_IDLE)
359 CTR0(KTR_PROC, "maybe_preempt: scheduling preemption");
360 ctd->td_owepreempt = 1;
368 * Constants for digital decay and forget:
369 * 90% of (ts_estcpu) usage in 5 * loadav time
370 * 95% of (ts_pctcpu) usage in 60 seconds (load insensitive)
371 * Note that, as ps(1) mentions, this can let percentages
372 * total over 100% (I've seen 137.9% for 3 processes).
374 * Note that schedclock() updates ts_estcpu and p_cpticks asynchronously.
376 * We wish to decay away 90% of ts_estcpu in (5 * loadavg) seconds.
377 * That is, the system wants to compute a value of decay such
378 * that the following for loop:
379 * for (i = 0; i < (5 * loadavg); i++)
380 * ts_estcpu *= decay;
383 * for all values of loadavg:
385 * Mathematically this loop can be expressed by saying:
386 * decay ** (5 * loadavg) ~= .1
388 * The system computes decay as:
389 * decay = (2 * loadavg) / (2 * loadavg + 1)
391 * We wish to prove that the system's computation of decay
392 * will always fulfill the equation:
393 * decay ** (5 * loadavg) ~= .1
395 * If we compute b as:
398 * decay = b / (b + 1)
400 * We now need to prove two things:
401 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1)
402 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg)
405 * For x close to zero, exp(x) =~ 1 + x, since
406 * exp(x) = 0! + x**1/1! + x**2/2! + ... .
407 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b.
408 * For x close to zero, ln(1+x) =~ x, since
409 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1
410 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1).
414 * Solve (factor)**(power) =~ .1 given power (5*loadav):
415 * solving for factor,
416 * ln(factor) =~ (-2.30/5*loadav), or
417 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) =
418 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED
421 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)):
423 * power*ln(b/(b+1)) =~ -2.30, or
424 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED
426 * Actual power values for the implemented algorithm are as follows:
428 * power: 5.68 10.32 14.94 19.55
431 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */
432 #define loadfactor(loadav) (2 * (loadav))
433 #define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE))
435 /* decay 95% of `ts_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
436 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
437 SYSCTL_UINT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
440 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
441 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
442 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
444 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
445 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
447 * If you don't want to bother with the faster/more-accurate formula, you
448 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
449 * (more general) method of calculating the %age of CPU used by a process.
451 #define CCPU_SHIFT 11
454 * Recompute process priorities, every hz ticks.
455 * MP-safe, called without the Giant mutex.
461 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
467 sx_slock(&allproc_lock);
468 FOREACH_PROC_IN_SYSTEM(p) {
470 if (p->p_state == PRS_NEW) {
474 FOREACH_THREAD_IN_PROC(p, td) {
476 ts = td_get_sched(td);
479 * Increment sleep time (if sleeping). We
480 * ignore overflow, as above.
483 * The td_sched slptimes are not touched in wakeup
484 * because the thread may not HAVE everything in
485 * memory? XXX I think this is out of date.
487 if (TD_ON_RUNQ(td)) {
489 td->td_flags &= ~TDF_DIDRUN;
490 } else if (TD_IS_RUNNING(td)) {
492 /* Do not clear TDF_DIDRUN */
493 } else if (td->td_flags & TDF_DIDRUN) {
495 td->td_flags &= ~TDF_DIDRUN;
499 * ts_pctcpu is only for ps and ttyinfo().
501 ts->ts_pctcpu = (ts->ts_pctcpu * ccpu) >> FSHIFT;
503 * If the td_sched has been idle the entire second,
504 * stop recalculating its priority until
507 if (ts->ts_cpticks != 0) {
508 #if (FSHIFT >= CCPU_SHIFT)
509 ts->ts_pctcpu += (realstathz == 100)
510 ? ((fixpt_t) ts->ts_cpticks) <<
511 (FSHIFT - CCPU_SHIFT) :
512 100 * (((fixpt_t) ts->ts_cpticks)
513 << (FSHIFT - CCPU_SHIFT)) / realstathz;
515 ts->ts_pctcpu += ((FSCALE - ccpu) *
517 FSCALE / realstathz)) >> FSHIFT;
522 * If there are ANY running threads in this process,
523 * then don't count it as sleeping.
524 * XXX: this is broken.
527 if (ts->ts_slptime > 1) {
529 * In an ideal world, this should not
530 * happen, because whoever woke us
531 * up from the long sleep should have
532 * unwound the slptime and reset our
533 * priority before we run at the stale
534 * priority. Should KASSERT at some
535 * point when all the cases are fixed.
542 if (ts->ts_slptime > 1) {
546 ts->ts_estcpu = decay_cpu(loadfac, ts->ts_estcpu);
548 resetpriority_thread(td);
553 sx_sunlock(&allproc_lock);
557 * Main loop for a kthread that executes schedcpu once a second.
560 schedcpu_thread(void)
570 * Recalculate the priority of a process after it has slept for a while.
571 * For all load averages >= 1 and max ts_estcpu of 255, sleeping for at
572 * least six times the loadfactor will decay ts_estcpu to zero.
575 updatepri(struct thread *td)
581 ts = td_get_sched(td);
582 loadfac = loadfactor(averunnable.ldavg[0]);
583 if (ts->ts_slptime > 5 * loadfac)
586 newcpu = ts->ts_estcpu;
587 ts->ts_slptime--; /* was incremented in schedcpu() */
588 while (newcpu && --ts->ts_slptime)
589 newcpu = decay_cpu(loadfac, newcpu);
590 ts->ts_estcpu = newcpu;
595 * Compute the priority of a process when running in user mode.
596 * Arrange to reschedule if the resulting priority is better
597 * than that of the current process.
600 resetpriority(struct thread *td)
604 if (td->td_pri_class != PRI_TIMESHARE)
606 newpriority = PUSER +
607 td_get_sched(td)->ts_estcpu / INVERSE_ESTCPU_WEIGHT +
608 NICE_WEIGHT * (td->td_proc->p_nice - PRIO_MIN);
609 newpriority = min(max(newpriority, PRI_MIN_TIMESHARE),
611 sched_user_prio(td, newpriority);
615 * Update the thread's priority when the associated process's user
619 resetpriority_thread(struct thread *td)
622 /* Only change threads with a time sharing user priority. */
623 if (td->td_priority < PRI_MIN_TIMESHARE ||
624 td->td_priority > PRI_MAX_TIMESHARE)
627 /* XXX the whole needresched thing is broken, but not silly. */
630 sched_prio(td, td->td_user_pri);
635 sched_setup(void *dummy)
640 /* Account for thread0. */
645 * This routine determines time constants after stathz and hz are setup.
648 sched_initticks(void *dummy)
651 realstathz = stathz ? stathz : hz;
652 sched_slice = realstathz / 10; /* ~100ms */
653 hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
657 /* External interfaces start here */
660 * Very early in the boot some setup of scheduler-specific
661 * parts of proc0 and of some scheduler resources needs to be done.
670 * Set up the scheduler specific parts of thread0.
672 thread0.td_lock = &sched_lock;
673 td_get_sched(&thread0)->ts_slice = sched_slice;
674 mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN | MTX_RECURSE);
681 return runq_check(&runq) + runq_check(&runq_pcpu[PCPU_GET(cpuid)]);
683 return runq_check(&runq);
688 sched_rr_interval(void)
691 /* Convert sched_slice from stathz to hz. */
692 return (imax(1, (sched_slice * hz + realstathz / 2) / realstathz));
696 * We adjust the priority of the current process. The priority of a
697 * process gets worse as it accumulates CPU time. The cpu usage
698 * estimator (ts_estcpu) is increased here. resetpriority() will
699 * compute a different priority each time ts_estcpu increases by
700 * INVERSE_ESTCPU_WEIGHT (until PRI_MAX_TIMESHARE is reached). The
701 * cpu usage estimator ramps up quite quickly when the process is
702 * running (linearly), and decays away exponentially, at a rate which
703 * is proportionally slower when the system is busy. The basic
704 * principle is that the system will 90% forget that the process used
705 * a lot of CPU time in 5 * loadav seconds. This causes the system to
706 * favor processes which haven't run much recently, and to round-robin
707 * among other processes.
710 sched_clock(struct thread *td)
712 struct pcpuidlestat *stat;
715 THREAD_LOCK_ASSERT(td, MA_OWNED);
716 ts = td_get_sched(td);
719 ts->ts_estcpu = ESTCPULIM(ts->ts_estcpu + 1);
720 if ((ts->ts_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) {
722 resetpriority_thread(td);
726 * Force a context switch if the current thread has used up a full
727 * time slice (default is 100ms).
729 if (!TD_IS_IDLETHREAD(td) && --ts->ts_slice <= 0) {
730 ts->ts_slice = sched_slice;
731 td->td_flags |= TDF_NEEDRESCHED | TDF_SLICEEND;
734 stat = DPCPU_PTR(idlestat);
735 stat->oldidlecalls = stat->idlecalls;
740 * Charge child's scheduling CPU usage to parent.
743 sched_exit(struct proc *p, struct thread *td)
746 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "proc exit",
747 "prio:%d", td->td_priority);
749 PROC_LOCK_ASSERT(p, MA_OWNED);
750 sched_exit_thread(FIRST_THREAD_IN_PROC(p), td);
754 sched_exit_thread(struct thread *td, struct thread *child)
757 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "exit",
758 "prio:%d", child->td_priority);
760 td_get_sched(td)->ts_estcpu = ESTCPULIM(td_get_sched(td)->ts_estcpu +
761 td_get_sched(child)->ts_estcpu);
764 if ((child->td_flags & TDF_NOLOAD) == 0)
766 thread_unlock(child);
770 sched_fork(struct thread *td, struct thread *childtd)
772 sched_fork_thread(td, childtd);
776 sched_fork_thread(struct thread *td, struct thread *childtd)
778 struct td_sched *ts, *tsc;
780 childtd->td_oncpu = NOCPU;
781 childtd->td_lastcpu = NOCPU;
782 childtd->td_lock = &sched_lock;
783 childtd->td_cpuset = cpuset_ref(td->td_cpuset);
784 childtd->td_domain.dr_policy = td->td_cpuset->cs_domain;
785 childtd->td_priority = childtd->td_base_pri;
786 ts = td_get_sched(childtd);
787 bzero(ts, sizeof(*ts));
788 tsc = td_get_sched(td);
789 ts->ts_estcpu = tsc->ts_estcpu;
790 ts->ts_flags |= (tsc->ts_flags & TSF_AFFINITY);
795 sched_nice(struct proc *p, int nice)
799 PROC_LOCK_ASSERT(p, MA_OWNED);
801 FOREACH_THREAD_IN_PROC(p, td) {
804 resetpriority_thread(td);
810 sched_class(struct thread *td, int class)
812 THREAD_LOCK_ASSERT(td, MA_OWNED);
813 td->td_pri_class = class;
817 * Adjust the priority of a thread.
820 sched_priority(struct thread *td, u_char prio)
824 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "priority change",
825 "prio:%d", td->td_priority, "new prio:%d", prio, KTR_ATTR_LINKED,
826 sched_tdname(curthread));
827 SDT_PROBE3(sched, , , change__pri, td, td->td_proc, prio);
828 if (td != curthread && prio > td->td_priority) {
829 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread),
830 "lend prio", "prio:%d", td->td_priority, "new prio:%d",
831 prio, KTR_ATTR_LINKED, sched_tdname(td));
832 SDT_PROBE4(sched, , , lend__pri, td, td->td_proc, prio,
835 THREAD_LOCK_ASSERT(td, MA_OWNED);
836 if (td->td_priority == prio)
838 td->td_priority = prio;
839 if (TD_ON_RUNQ(td) && td->td_rqindex != (prio / RQ_PPQ)) {
841 sched_add(td, SRQ_BORING);
846 * Update a thread's priority when it is lent another thread's
850 sched_lend_prio(struct thread *td, u_char prio)
853 td->td_flags |= TDF_BORROWING;
854 sched_priority(td, prio);
858 * Restore a thread's priority when priority propagation is
859 * over. The prio argument is the minimum priority the thread
860 * needs to have to satisfy other possible priority lending
861 * requests. If the thread's regulary priority is less
862 * important than prio the thread will keep a priority boost
866 sched_unlend_prio(struct thread *td, u_char prio)
870 if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
871 td->td_base_pri <= PRI_MAX_TIMESHARE)
872 base_pri = td->td_user_pri;
874 base_pri = td->td_base_pri;
875 if (prio >= base_pri) {
876 td->td_flags &= ~TDF_BORROWING;
877 sched_prio(td, base_pri);
879 sched_lend_prio(td, prio);
883 sched_prio(struct thread *td, u_char prio)
887 /* First, update the base priority. */
888 td->td_base_pri = prio;
891 * If the thread is borrowing another thread's priority, don't ever
892 * lower the priority.
894 if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
897 /* Change the real priority. */
898 oldprio = td->td_priority;
899 sched_priority(td, prio);
902 * If the thread is on a turnstile, then let the turnstile update
905 if (TD_ON_LOCK(td) && oldprio != prio)
906 turnstile_adjust(td, oldprio);
910 sched_user_prio(struct thread *td, u_char prio)
913 THREAD_LOCK_ASSERT(td, MA_OWNED);
914 td->td_base_user_pri = prio;
915 if (td->td_lend_user_pri <= prio)
917 td->td_user_pri = prio;
921 sched_lend_user_prio(struct thread *td, u_char prio)
924 THREAD_LOCK_ASSERT(td, MA_OWNED);
925 td->td_lend_user_pri = prio;
926 td->td_user_pri = min(prio, td->td_base_user_pri);
927 if (td->td_priority > td->td_user_pri)
928 sched_prio(td, td->td_user_pri);
929 else if (td->td_priority != td->td_user_pri)
930 td->td_flags |= TDF_NEEDRESCHED;
934 * Like the above but first check if there is anything to do.
937 sched_lend_user_prio_cond(struct thread *td, u_char prio)
940 if (td->td_lend_user_pri != prio)
942 if (td->td_user_pri != min(prio, td->td_base_user_pri))
944 if (td->td_priority >= td->td_user_pri)
950 sched_lend_user_prio(td, prio);
955 sched_sleep(struct thread *td, int pri)
958 THREAD_LOCK_ASSERT(td, MA_OWNED);
959 td->td_slptick = ticks;
960 td_get_sched(td)->ts_slptime = 0;
961 if (pri != 0 && PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
963 if (TD_IS_SUSPENDED(td) || pri >= PSOCK)
964 td->td_flags |= TDF_CANSWAP;
968 sched_switch(struct thread *td, struct thread *newtd, int flags)
976 ts = td_get_sched(td);
979 THREAD_LOCK_ASSERT(td, MA_OWNED);
982 * Switch to the sched lock to fix things up and pick
984 * Block the td_lock in order to avoid breaking the critical path.
986 if (td->td_lock != &sched_lock) {
987 mtx_lock_spin(&sched_lock);
988 tmtx = thread_lock_block(td);
991 if ((td->td_flags & TDF_NOLOAD) == 0)
994 td->td_lastcpu = td->td_oncpu;
995 preempted = (td->td_flags & TDF_SLICEEND) == 0 &&
996 (flags & SW_PREEMPT) != 0;
997 td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND);
998 td->td_owepreempt = 0;
999 td->td_oncpu = NOCPU;
1002 * At the last moment, if this thread is still marked RUNNING,
1003 * then put it back on the run queue as it has not been suspended
1004 * or stopped or any thing else similar. We never put the idle
1005 * threads on the run queue, however.
1007 if (td->td_flags & TDF_IDLETD) {
1010 CPU_CLR(PCPU_GET(cpuid), &idle_cpus_mask);
1013 if (TD_IS_RUNNING(td)) {
1014 /* Put us back on the run queue. */
1015 sched_add(td, preempted ?
1016 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
1017 SRQ_OURSELF|SRQ_YIELDING);
1022 * The thread we are about to run needs to be counted
1023 * as if it had been added to the run queue and selected.
1029 KASSERT((newtd->td_inhibitors == 0),
1030 ("trying to run inhibited thread"));
1031 newtd->td_flags |= TDF_DIDRUN;
1032 TD_SET_RUNNING(newtd);
1033 if ((newtd->td_flags & TDF_NOLOAD) == 0)
1036 newtd = choosethread();
1037 MPASS(newtd->td_lock == &sched_lock);
1040 #if (KTR_COMPILE & KTR_SCHED) != 0
1041 if (TD_IS_IDLETHREAD(td))
1042 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "idle",
1043 "prio:%d", td->td_priority);
1045 KTR_STATE3(KTR_SCHED, "thread", sched_tdname(td), KTDSTATE(td),
1046 "prio:%d", td->td_priority, "wmesg:\"%s\"", td->td_wmesg,
1047 "lockname:\"%s\"", td->td_lockname);
1052 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1053 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
1056 SDT_PROBE2(sched, , , off__cpu, newtd, newtd->td_proc);
1059 lock_profile_release_lock(&sched_lock.lock_object);
1060 #ifdef KDTRACE_HOOKS
1062 * If DTrace has set the active vtime enum to anything
1063 * other than INACTIVE (0), then it should have set the
1066 if (dtrace_vtime_active)
1067 (*dtrace_vtime_switch_func)(newtd);
1070 cpu_switch(td, newtd, tmtx != NULL ? tmtx : td->td_lock);
1071 lock_profile_obtain_lock_success(&sched_lock.lock_object,
1072 0, 0, __FILE__, __LINE__);
1074 * Where am I? What year is it?
1075 * We are in the same thread that went to sleep above,
1076 * but any amount of time may have passed. All our context
1077 * will still be available as will local variables.
1078 * PCPU values however may have changed as we may have
1079 * changed CPU so don't trust cached values of them.
1080 * New threads will go to fork_exit() instead of here
1081 * so if you change things here you may need to change
1084 * If the thread above was exiting it will never wake
1085 * up again here, so either it has saved everything it
1086 * needed to, or the thread_wait() or wait() will
1090 SDT_PROBE0(sched, , , on__cpu);
1092 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
1093 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
1096 SDT_PROBE0(sched, , , remain__cpu);
1098 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running",
1099 "prio:%d", td->td_priority);
1102 if (td->td_flags & TDF_IDLETD)
1103 CPU_SET(PCPU_GET(cpuid), &idle_cpus_mask);
1105 sched_lock.mtx_lock = (uintptr_t)td;
1106 td->td_oncpu = PCPU_GET(cpuid);
1107 MPASS(td->td_lock == &sched_lock);
1111 sched_wakeup(struct thread *td)
1113 struct td_sched *ts;
1115 THREAD_LOCK_ASSERT(td, MA_OWNED);
1116 ts = td_get_sched(td);
1117 td->td_flags &= ~TDF_CANSWAP;
1118 if (ts->ts_slptime > 1) {
1124 ts->ts_slice = sched_slice;
1125 sched_add(td, SRQ_BORING);
1130 forward_wakeup(int cpunum)
1133 cpuset_t dontuse, map, map2;
1137 mtx_assert(&sched_lock, MA_OWNED);
1139 CTR0(KTR_RUNQ, "forward_wakeup()");
1141 if ((!forward_wakeup_enabled) ||
1142 (forward_wakeup_use_mask == 0 && forward_wakeup_use_loop == 0))
1144 if (!smp_started || panicstr)
1147 forward_wakeups_requested++;
1150 * Check the idle mask we received against what we calculated
1151 * before in the old version.
1153 me = PCPU_GET(cpuid);
1155 /* Don't bother if we should be doing it ourself. */
1156 if (CPU_ISSET(me, &idle_cpus_mask) &&
1157 (cpunum == NOCPU || me == cpunum))
1160 CPU_SETOF(me, &dontuse);
1161 CPU_OR(&dontuse, &stopped_cpus);
1162 CPU_OR(&dontuse, &hlt_cpus_mask);
1164 if (forward_wakeup_use_loop) {
1165 STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
1167 if (!CPU_ISSET(id, &dontuse) &&
1168 pc->pc_curthread == pc->pc_idlethread) {
1174 if (forward_wakeup_use_mask) {
1175 map = idle_cpus_mask;
1176 CPU_NAND(&map, &dontuse);
1178 /* If they are both on, compare and use loop if different. */
1179 if (forward_wakeup_use_loop) {
1180 if (CPU_CMP(&map, &map2)) {
1181 printf("map != map2, loop method preferred\n");
1189 /* If we only allow a specific CPU, then mask off all the others. */
1190 if (cpunum != NOCPU) {
1191 KASSERT((cpunum <= mp_maxcpus),("forward_wakeup: bad cpunum."));
1192 iscpuset = CPU_ISSET(cpunum, &map);
1196 CPU_SETOF(cpunum, &map);
1198 if (!CPU_EMPTY(&map)) {
1199 forward_wakeups_delivered++;
1200 STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
1202 if (!CPU_ISSET(id, &map))
1204 if (cpu_idle_wakeup(pc->pc_cpuid))
1207 if (!CPU_EMPTY(&map))
1208 ipi_selected(map, IPI_AST);
1211 if (cpunum == NOCPU)
1212 printf("forward_wakeup: Idle processor not found\n");
1217 kick_other_cpu(int pri, int cpuid)
1222 pcpu = pcpu_find(cpuid);
1223 if (CPU_ISSET(cpuid, &idle_cpus_mask)) {
1224 forward_wakeups_delivered++;
1225 if (!cpu_idle_wakeup(cpuid))
1226 ipi_cpu(cpuid, IPI_AST);
1230 cpri = pcpu->pc_curthread->td_priority;
1234 #if defined(IPI_PREEMPTION) && defined(PREEMPTION)
1235 #if !defined(FULL_PREEMPTION)
1236 if (pri <= PRI_MAX_ITHD)
1237 #endif /* ! FULL_PREEMPTION */
1239 ipi_cpu(cpuid, IPI_PREEMPT);
1242 #endif /* defined(IPI_PREEMPTION) && defined(PREEMPTION) */
1244 pcpu->pc_curthread->td_flags |= TDF_NEEDRESCHED;
1245 ipi_cpu(cpuid, IPI_AST);
1252 sched_pickcpu(struct thread *td)
1256 mtx_assert(&sched_lock, MA_OWNED);
1258 if (td->td_lastcpu != NOCPU && THREAD_CAN_SCHED(td, td->td_lastcpu))
1259 best = td->td_lastcpu;
1263 if (!THREAD_CAN_SCHED(td, cpu))
1268 else if (runq_length[cpu] < runq_length[best])
1271 KASSERT(best != NOCPU, ("no valid CPUs"));
1278 sched_add(struct thread *td, int flags)
1282 struct td_sched *ts;
1287 ts = td_get_sched(td);
1288 THREAD_LOCK_ASSERT(td, MA_OWNED);
1289 KASSERT((td->td_inhibitors == 0),
1290 ("sched_add: trying to run inhibited thread"));
1291 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
1292 ("sched_add: bad thread state"));
1293 KASSERT(td->td_flags & TDF_INMEM,
1294 ("sched_add: thread swapped out"));
1296 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
1297 "prio:%d", td->td_priority, KTR_ATTR_LINKED,
1298 sched_tdname(curthread));
1299 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
1300 KTR_ATTR_LINKED, sched_tdname(td));
1301 SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL,
1302 flags & SRQ_PREEMPTED);
1306 * Now that the thread is moving to the run-queue, set the lock
1307 * to the scheduler's lock.
1309 if (td->td_lock != &sched_lock) {
1310 mtx_lock_spin(&sched_lock);
1311 thread_lock_set(td, &sched_lock);
1316 * If SMP is started and the thread is pinned or otherwise limited to
1317 * a specific set of CPUs, queue the thread to a per-CPU run queue.
1318 * Otherwise, queue the thread to the global run queue.
1320 * If SMP has not yet been started we must use the global run queue
1321 * as per-CPU state may not be initialized yet and we may crash if we
1322 * try to access the per-CPU run queues.
1324 if (smp_started && (td->td_pinned != 0 || td->td_flags & TDF_BOUND ||
1325 ts->ts_flags & TSF_AFFINITY)) {
1326 if (td->td_pinned != 0)
1327 cpu = td->td_lastcpu;
1328 else if (td->td_flags & TDF_BOUND) {
1329 /* Find CPU from bound runq. */
1330 KASSERT(SKE_RUNQ_PCPU(ts),
1331 ("sched_add: bound td_sched not on cpu runq"));
1332 cpu = ts->ts_runq - &runq_pcpu[0];
1334 /* Find a valid CPU for our cpuset */
1335 cpu = sched_pickcpu(td);
1336 ts->ts_runq = &runq_pcpu[cpu];
1339 "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td,
1343 "sched_add: adding td_sched:%p (td:%p) to gbl runq", ts,
1346 ts->ts_runq = &runq;
1349 if ((td->td_flags & TDF_NOLOAD) == 0)
1351 runq_add(ts->ts_runq, td, flags);
1355 cpuid = PCPU_GET(cpuid);
1356 if (single_cpu && cpu != cpuid) {
1357 kick_other_cpu(td->td_priority, cpu);
1360 tidlemsk = idle_cpus_mask;
1361 CPU_NAND(&tidlemsk, &hlt_cpus_mask);
1362 CPU_CLR(cpuid, &tidlemsk);
1364 if (!CPU_ISSET(cpuid, &idle_cpus_mask) &&
1365 ((flags & SRQ_INTR) == 0) &&
1366 !CPU_EMPTY(&tidlemsk))
1367 forwarded = forward_wakeup(cpu);
1371 if (!maybe_preempt(td))
1378 struct td_sched *ts;
1380 ts = td_get_sched(td);
1381 THREAD_LOCK_ASSERT(td, MA_OWNED);
1382 KASSERT((td->td_inhibitors == 0),
1383 ("sched_add: trying to run inhibited thread"));
1384 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
1385 ("sched_add: bad thread state"));
1386 KASSERT(td->td_flags & TDF_INMEM,
1387 ("sched_add: thread swapped out"));
1388 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
1389 "prio:%d", td->td_priority, KTR_ATTR_LINKED,
1390 sched_tdname(curthread));
1391 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
1392 KTR_ATTR_LINKED, sched_tdname(td));
1393 SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL,
1394 flags & SRQ_PREEMPTED);
1397 * Now that the thread is moving to the run-queue, set the lock
1398 * to the scheduler's lock.
1400 if (td->td_lock != &sched_lock) {
1401 mtx_lock_spin(&sched_lock);
1402 thread_lock_set(td, &sched_lock);
1405 CTR2(KTR_RUNQ, "sched_add: adding td_sched:%p (td:%p) to runq", ts, td);
1406 ts->ts_runq = &runq;
1408 if ((td->td_flags & TDF_NOLOAD) == 0)
1410 runq_add(ts->ts_runq, td, flags);
1411 if (!maybe_preempt(td))
1417 sched_rem(struct thread *td)
1419 struct td_sched *ts;
1421 ts = td_get_sched(td);
1422 KASSERT(td->td_flags & TDF_INMEM,
1423 ("sched_rem: thread swapped out"));
1424 KASSERT(TD_ON_RUNQ(td),
1425 ("sched_rem: thread not on run queue"));
1426 mtx_assert(&sched_lock, MA_OWNED);
1427 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq rem",
1428 "prio:%d", td->td_priority, KTR_ATTR_LINKED,
1429 sched_tdname(curthread));
1430 SDT_PROBE3(sched, , , dequeue, td, td->td_proc, NULL);
1432 if ((td->td_flags & TDF_NOLOAD) == 0)
1435 if (ts->ts_runq != &runq)
1436 runq_length[ts->ts_runq - runq_pcpu]--;
1438 runq_remove(ts->ts_runq, td);
1443 * Select threads to run. Note that running threads still consume a
1452 mtx_assert(&sched_lock, MA_OWNED);
1454 struct thread *tdcpu;
1457 td = runq_choose_fuzz(&runq, runq_fuzz);
1458 tdcpu = runq_choose(&runq_pcpu[PCPU_GET(cpuid)]);
1462 tdcpu->td_priority < td->td_priority)) {
1463 CTR2(KTR_RUNQ, "choosing td %p from pcpu runq %d", tdcpu,
1466 rq = &runq_pcpu[PCPU_GET(cpuid)];
1468 CTR1(KTR_RUNQ, "choosing td_sched %p from main runq", td);
1473 td = runq_choose(&runq);
1479 runq_length[PCPU_GET(cpuid)]--;
1481 runq_remove(rq, td);
1482 td->td_flags |= TDF_DIDRUN;
1484 KASSERT(td->td_flags & TDF_INMEM,
1485 ("sched_choose: thread swapped out"));
1488 return (PCPU_GET(idlethread));
1492 sched_preempt(struct thread *td)
1495 SDT_PROBE2(sched, , , surrender, td, td->td_proc);
1497 if (td->td_critnest > 1)
1498 td->td_owepreempt = 1;
1500 mi_switch(SW_INVOL | SW_PREEMPT | SWT_PREEMPT, NULL);
1505 sched_userret_slowpath(struct thread *td)
1509 td->td_priority = td->td_user_pri;
1510 td->td_base_pri = td->td_user_pri;
1515 sched_bind(struct thread *td, int cpu)
1517 struct td_sched *ts;
1519 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED);
1520 KASSERT(td == curthread, ("sched_bind: can only bind curthread"));
1522 ts = td_get_sched(td);
1524 td->td_flags |= TDF_BOUND;
1526 ts->ts_runq = &runq_pcpu[cpu];
1527 if (PCPU_GET(cpuid) == cpu)
1530 mi_switch(SW_VOL, NULL);
1535 sched_unbind(struct thread* td)
1537 THREAD_LOCK_ASSERT(td, MA_OWNED);
1538 KASSERT(td == curthread, ("sched_unbind: can only bind curthread"));
1539 td->td_flags &= ~TDF_BOUND;
1543 sched_is_bound(struct thread *td)
1545 THREAD_LOCK_ASSERT(td, MA_OWNED);
1546 return (td->td_flags & TDF_BOUND);
1550 sched_relinquish(struct thread *td)
1553 mi_switch(SW_VOL | SWT_RELINQUISH, NULL);
1560 return (sched_tdcnt);
1564 sched_sizeof_proc(void)
1566 return (sizeof(struct proc));
1570 sched_sizeof_thread(void)
1572 return (sizeof(struct thread) + sizeof(struct td_sched));
1576 sched_pctcpu(struct thread *td)
1578 struct td_sched *ts;
1580 THREAD_LOCK_ASSERT(td, MA_OWNED);
1581 ts = td_get_sched(td);
1582 return (ts->ts_pctcpu);
1587 * Calculates the contribution to the thread cpu usage for the latest
1588 * (unfinished) second.
1591 sched_pctcpu_delta(struct thread *td)
1593 struct td_sched *ts;
1597 THREAD_LOCK_ASSERT(td, MA_OWNED);
1598 ts = td_get_sched(td);
1600 realstathz = stathz ? stathz : hz;
1601 if (ts->ts_cpticks != 0) {
1602 #if (FSHIFT >= CCPU_SHIFT)
1603 delta = (realstathz == 100)
1604 ? ((fixpt_t) ts->ts_cpticks) <<
1605 (FSHIFT - CCPU_SHIFT) :
1606 100 * (((fixpt_t) ts->ts_cpticks)
1607 << (FSHIFT - CCPU_SHIFT)) / realstathz;
1609 delta = ((FSCALE - ccpu) *
1611 FSCALE / realstathz)) >> FSHIFT;
1620 sched_estcpu(struct thread *td)
1623 return (td_get_sched(td)->ts_estcpu);
1627 * The actual idle process.
1630 sched_idletd(void *dummy)
1632 struct pcpuidlestat *stat;
1634 THREAD_NO_SLEEPING();
1635 stat = DPCPU_PTR(idlestat);
1637 mtx_assert(&Giant, MA_NOTOWNED);
1639 while (sched_runnable() == 0) {
1640 cpu_idle(stat->idlecalls + stat->oldidlecalls > 64);
1644 mtx_lock_spin(&sched_lock);
1645 mi_switch(SW_VOL | SWT_IDLE, NULL);
1646 mtx_unlock_spin(&sched_lock);
1651 * A CPU is entering for the first time or a thread is exiting.
1654 sched_throw(struct thread *td)
1657 * Correct spinlock nesting. The idle thread context that we are
1658 * borrowing was created so that it would start out with a single
1659 * spin lock (sched_lock) held in fork_trampoline(). Since we've
1660 * explicitly acquired locks in this function, the nesting count
1661 * is now 2 rather than 1. Since we are nested, calling
1662 * spinlock_exit() will simply adjust the counts without allowing
1663 * spin lock using code to interrupt us.
1666 mtx_lock_spin(&sched_lock);
1668 PCPU_SET(switchtime, cpu_ticks());
1669 PCPU_SET(switchticks, ticks);
1671 lock_profile_release_lock(&sched_lock.lock_object);
1672 MPASS(td->td_lock == &sched_lock);
1673 td->td_lastcpu = td->td_oncpu;
1674 td->td_oncpu = NOCPU;
1676 mtx_assert(&sched_lock, MA_OWNED);
1677 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
1678 cpu_throw(td, choosethread()); /* doesn't return */
1682 sched_fork_exit(struct thread *td)
1686 * Finish setting up thread glue so that it begins execution in a
1687 * non-nested critical section with sched_lock held but not recursed.
1689 td->td_oncpu = PCPU_GET(cpuid);
1690 sched_lock.mtx_lock = (uintptr_t)td;
1691 lock_profile_obtain_lock_success(&sched_lock.lock_object,
1692 0, 0, __FILE__, __LINE__);
1693 THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED);
1695 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running",
1696 "prio:%d", td->td_priority);
1697 SDT_PROBE0(sched, , , on__cpu);
1701 sched_tdname(struct thread *td)
1704 struct td_sched *ts;
1706 ts = td_get_sched(td);
1707 if (ts->ts_name[0] == '\0')
1708 snprintf(ts->ts_name, sizeof(ts->ts_name),
1709 "%s tid %d", td->td_name, td->td_tid);
1710 return (ts->ts_name);
1712 return (td->td_name);
1718 sched_clear_tdname(struct thread *td)
1720 struct td_sched *ts;
1722 ts = td_get_sched(td);
1723 ts->ts_name[0] = '\0';
1728 sched_affinity(struct thread *td)
1731 struct td_sched *ts;
1734 THREAD_LOCK_ASSERT(td, MA_OWNED);
1737 * Set the TSF_AFFINITY flag if there is at least one CPU this
1738 * thread can't run on.
1740 ts = td_get_sched(td);
1741 ts->ts_flags &= ~TSF_AFFINITY;
1743 if (!THREAD_CAN_SCHED(td, cpu)) {
1744 ts->ts_flags |= TSF_AFFINITY;
1750 * If this thread can run on all CPUs, nothing else to do.
1752 if (!(ts->ts_flags & TSF_AFFINITY))
1755 /* Pinned threads and bound threads should be left alone. */
1756 if (td->td_pinned != 0 || td->td_flags & TDF_BOUND)
1759 switch (td->td_state) {
1762 * If we are on a per-CPU runqueue that is in the set,
1763 * then nothing needs to be done.
1765 if (ts->ts_runq != &runq &&
1766 THREAD_CAN_SCHED(td, ts->ts_runq - runq_pcpu))
1769 /* Put this thread on a valid per-CPU runqueue. */
1771 sched_add(td, SRQ_BORING);
1775 * See if our current CPU is in the set. If not, force a
1778 if (THREAD_CAN_SCHED(td, td->td_oncpu))
1781 td->td_flags |= TDF_NEEDRESCHED;
1782 if (td != curthread)
1783 ipi_cpu(cpu, IPI_AST);