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35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
38 #include "opt_hwpmc_hooks.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
45 #include <sys/kthread.h>
46 #include <sys/mutex.h>
48 #include <sys/resourcevar.h>
49 #include <sys/sched.h>
51 #include <sys/sysctl.h>
53 #include <sys/turnstile.h>
55 #include <machine/pcb.h>
56 #include <machine/smp.h>
59 #include <sys/pmckern.h>
63 * INVERSE_ESTCPU_WEIGHT is only suitable for statclock() frequencies in
64 * the range 100-256 Hz (approximately).
66 #define ESTCPULIM(e) \
67 min((e), INVERSE_ESTCPU_WEIGHT * (NICE_WEIGHT * (PRIO_MAX - PRIO_MIN) - \
68 RQ_PPQ) + INVERSE_ESTCPU_WEIGHT - 1)
70 #define INVERSE_ESTCPU_WEIGHT (8 * smp_cpus)
72 #define INVERSE_ESTCPU_WEIGHT 8 /* 1 / (priorities per estcpu level). */
74 #define NICE_WEIGHT 1 /* Priorities per nice level. */
77 * The schedulable entity that runs a context.
78 * This is an extension to the thread structure and is tailored to
79 * the requirements of this scheduler
82 TAILQ_ENTRY(td_sched) ts_procq; /* (j/z) Run queue. */
83 struct thread *ts_thread; /* (*) Active associated thread. */
84 fixpt_t ts_pctcpu; /* (j) %cpu during p_swtime. */
85 u_char ts_rqindex; /* (j) Run queue index. */
87 TSS_THREAD = 0x0, /* slaved to thread state */
89 } ts_state; /* (j) TD_STAT in scheduler status. */
90 int ts_cpticks; /* (j) Ticks of cpu time. */
91 struct runq *ts_runq; /* runq the thread is currently on */
94 /* flags kept in td_flags */
95 #define TDF_DIDRUN TDF_SCHED0 /* thread actually ran. */
96 #define TDF_EXIT TDF_SCHED1 /* thread is being killed. */
97 #define TDF_BOUND TDF_SCHED2
99 #define ts_flags ts_thread->td_flags
100 #define TSF_DIDRUN TDF_DIDRUN /* thread actually ran. */
101 #define TSF_EXIT TDF_EXIT /* thread is being killed. */
102 #define TSF_BOUND TDF_BOUND /* stuck to one CPU */
104 #define SKE_RUNQ_PCPU(ts) \
105 ((ts)->ts_runq != 0 && (ts)->ts_runq != &runq)
107 static struct td_sched td_sched0;
109 static int sched_tdcnt; /* Total runnable threads in the system. */
110 static int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
111 #define SCHED_QUANTUM (hz / 10) /* Default sched quantum */
113 static struct callout roundrobin_callout;
115 static struct td_sched *sched_choose(void);
117 static void setup_runqs(void);
118 static void roundrobin(void *arg);
119 static void schedcpu(void);
120 static void schedcpu_thread(void);
121 static void sched_priority(struct thread *td, u_char prio);
122 static void sched_setup(void *dummy);
123 static void maybe_resched(struct thread *td);
124 static void updatepri(struct thread *td);
125 static void resetpriority(struct thread *td);
126 static void resetpriority_thread(struct thread *td);
128 static int forward_wakeup(int cpunum);
131 static struct kproc_desc sched_kp = {
136 SYSINIT(schedcpu, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, kproc_start, &sched_kp)
137 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL)
142 static struct runq runq;
148 static struct runq runq_pcpu[MAXCPU];
157 for (i = 0; i < MAXCPU; ++i)
158 runq_init(&runq_pcpu[i]);
165 sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
169 new_val = sched_quantum * tick;
170 error = sysctl_handle_int(oidp, &new_val, 0, req);
171 if (error != 0 || req->newptr == NULL)
175 sched_quantum = new_val / tick;
176 hogticks = 2 * sched_quantum;
180 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RD, 0, "Scheduler");
182 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "4BSD", 0,
185 SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW,
186 0, sizeof sched_quantum, sysctl_kern_quantum, "I",
187 "Roundrobin scheduling quantum in microseconds");
190 /* Enable forwarding of wakeups to all other cpus */
191 SYSCTL_NODE(_kern_sched, OID_AUTO, ipiwakeup, CTLFLAG_RD, NULL, "Kernel SMP");
193 static int forward_wakeup_enabled = 1;
194 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, enabled, CTLFLAG_RW,
195 &forward_wakeup_enabled, 0,
196 "Forwarding of wakeup to idle CPUs");
198 static int forward_wakeups_requested = 0;
199 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, requested, CTLFLAG_RD,
200 &forward_wakeups_requested, 0,
201 "Requests for Forwarding of wakeup to idle CPUs");
203 static int forward_wakeups_delivered = 0;
204 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, delivered, CTLFLAG_RD,
205 &forward_wakeups_delivered, 0,
206 "Completed Forwarding of wakeup to idle CPUs");
208 static int forward_wakeup_use_mask = 1;
209 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, usemask, CTLFLAG_RW,
210 &forward_wakeup_use_mask, 0,
211 "Use the mask of idle cpus");
213 static int forward_wakeup_use_loop = 0;
214 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, useloop, CTLFLAG_RW,
215 &forward_wakeup_use_loop, 0,
216 "Use a loop to find idle cpus");
218 static int forward_wakeup_use_single = 0;
219 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, onecpu, CTLFLAG_RW,
220 &forward_wakeup_use_single, 0,
221 "Only signal one idle cpu");
223 static int forward_wakeup_use_htt = 0;
224 SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, htt2, CTLFLAG_RW,
225 &forward_wakeup_use_htt, 0,
230 static int sched_followon = 0;
231 SYSCTL_INT(_kern_sched, OID_AUTO, followon, CTLFLAG_RW,
233 "allow threads to share a quantum");
240 CTR1(KTR_SCHED, "global load: %d", sched_tdcnt);
247 CTR1(KTR_SCHED, "global load: %d", sched_tdcnt);
250 * Arrange to reschedule if necessary, taking the priorities and
251 * schedulers into account.
254 maybe_resched(struct thread *td)
257 mtx_assert(&sched_lock, MA_OWNED);
258 if (td->td_priority < curthread->td_priority)
259 curthread->td_flags |= TDF_NEEDRESCHED;
263 * Force switch among equal priority processes every 100ms.
264 * We don't actually need to force a context switch of the current process.
265 * The act of firing the event triggers a context switch to softclock() and
266 * then switching back out again which is equivalent to a preemption, thus
267 * no further work is needed on the local CPU.
271 roundrobin(void *arg)
275 mtx_lock_spin(&sched_lock);
276 forward_roundrobin();
277 mtx_unlock_spin(&sched_lock);
280 callout_reset(&roundrobin_callout, sched_quantum, roundrobin, NULL);
284 * Constants for digital decay and forget:
285 * 90% of (td_estcpu) usage in 5 * loadav time
286 * 95% of (ts_pctcpu) usage in 60 seconds (load insensitive)
287 * Note that, as ps(1) mentions, this can let percentages
288 * total over 100% (I've seen 137.9% for 3 processes).
290 * Note that schedclock() updates td_estcpu and p_cpticks asynchronously.
292 * We wish to decay away 90% of td_estcpu in (5 * loadavg) seconds.
293 * That is, the system wants to compute a value of decay such
294 * that the following for loop:
295 * for (i = 0; i < (5 * loadavg); i++)
296 * td_estcpu *= decay;
299 * for all values of loadavg:
301 * Mathematically this loop can be expressed by saying:
302 * decay ** (5 * loadavg) ~= .1
304 * The system computes decay as:
305 * decay = (2 * loadavg) / (2 * loadavg + 1)
307 * We wish to prove that the system's computation of decay
308 * will always fulfill the equation:
309 * decay ** (5 * loadavg) ~= .1
311 * If we compute b as:
314 * decay = b / (b + 1)
316 * We now need to prove two things:
317 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1)
318 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg)
321 * For x close to zero, exp(x) =~ 1 + x, since
322 * exp(x) = 0! + x**1/1! + x**2/2! + ... .
323 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b.
324 * For x close to zero, ln(1+x) =~ x, since
325 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1
326 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1).
330 * Solve (factor)**(power) =~ .1 given power (5*loadav):
331 * solving for factor,
332 * ln(factor) =~ (-2.30/5*loadav), or
333 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) =
334 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED
337 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)):
339 * power*ln(b/(b+1)) =~ -2.30, or
340 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED
342 * Actual power values for the implemented algorithm are as follows:
344 * power: 5.68 10.32 14.94 19.55
347 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */
348 #define loadfactor(loadav) (2 * (loadav))
349 #define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE))
351 /* decay 95% of `ts_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
352 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
353 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
356 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
357 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
358 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
360 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
361 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
363 * If you don't want to bother with the faster/more-accurate formula, you
364 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
365 * (more general) method of calculating the %age of CPU used by a process.
367 #define CCPU_SHIFT 11
370 * Recompute process priorities, every hz ticks.
371 * MP-safe, called without the Giant mutex.
377 register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
381 int awake, realstathz;
383 realstathz = stathz ? stathz : hz;
384 sx_slock(&allproc_lock);
385 FOREACH_PROC_IN_SYSTEM(p) {
387 * Prevent state changes and protect run queue.
389 mtx_lock_spin(&sched_lock);
391 * Increment time in/out of memory. We ignore overflow; with
392 * 16-bit int's (remember them?) overflow takes 45 days.
395 FOREACH_THREAD_IN_PROC(p, td) {
399 * Increment sleep time (if sleeping). We
400 * ignore overflow, as above.
403 * The td_sched slptimes are not touched in wakeup
404 * because the thread may not HAVE everything in
405 * memory? XXX I think this is out of date.
407 if (ts->ts_state == TSS_ONRUNQ) {
409 ts->ts_flags &= ~TSF_DIDRUN;
410 } else if ((ts->ts_state == TSS_THREAD) &&
411 (TD_IS_RUNNING(td))) {
413 /* Do not clear TSF_DIDRUN */
414 } else if (ts->ts_flags & TSF_DIDRUN) {
416 ts->ts_flags &= ~TSF_DIDRUN;
420 * ts_pctcpu is only for ps and ttyinfo().
421 * Do it per td_sched, and add them up at the end?
424 ts->ts_pctcpu = (ts->ts_pctcpu * ccpu) >> FSHIFT;
426 * If the td_sched has been idle the entire second,
427 * stop recalculating its priority until
430 if (ts->ts_cpticks != 0) {
431 #if (FSHIFT >= CCPU_SHIFT)
432 ts->ts_pctcpu += (realstathz == 100)
433 ? ((fixpt_t) ts->ts_cpticks) <<
434 (FSHIFT - CCPU_SHIFT) :
435 100 * (((fixpt_t) ts->ts_cpticks)
436 << (FSHIFT - CCPU_SHIFT)) / realstathz;
438 ts->ts_pctcpu += ((FSCALE - ccpu) *
440 FSCALE / realstathz)) >> FSHIFT;
445 * If there are ANY running threads in this process,
446 * then don't count it as sleeping.
451 if (p->p_slptime > 1) {
453 * In an ideal world, this should not
454 * happen, because whoever woke us
455 * up from the long sleep should have
456 * unwound the slptime and reset our
457 * priority before we run at the stale
458 * priority. Should KASSERT at some
459 * point when all the cases are fixed.
466 if (td->td_slptime > 1)
468 td->td_estcpu = decay_cpu(loadfac, td->td_estcpu);
470 resetpriority_thread(td);
471 } /* end of thread loop */
472 mtx_unlock_spin(&sched_lock);
473 } /* end of process loop */
474 sx_sunlock(&allproc_lock);
478 * Main loop for a kthread that executes schedcpu once a second.
481 schedcpu_thread(void)
487 tsleep(&nowake, 0, "-", hz);
492 * Recalculate the priority of a process after it has slept for a while.
493 * For all load averages >= 1 and max td_estcpu of 255, sleeping for at
494 * least six times the loadfactor will decay td_estcpu to zero.
497 updatepri(struct thread *td)
499 register fixpt_t loadfac;
500 register unsigned int newcpu;
502 loadfac = loadfactor(averunnable.ldavg[0]);
503 if (td->td_slptime > 5 * loadfac)
506 newcpu = td->td_estcpu;
507 td->td_slptime--; /* was incremented in schedcpu() */
508 while (newcpu && --td->td_slptime)
509 newcpu = decay_cpu(loadfac, newcpu);
510 td->td_estcpu = newcpu;
515 * Compute the priority of a process when running in user mode.
516 * Arrange to reschedule if the resulting priority is better
517 * than that of the current process.
520 resetpriority(struct thread *td)
522 register unsigned int newpriority;
524 if (td->td_pri_class == PRI_TIMESHARE) {
525 newpriority = PUSER + td->td_estcpu / INVERSE_ESTCPU_WEIGHT +
526 NICE_WEIGHT * (td->td_proc->p_nice - PRIO_MIN);
527 newpriority = min(max(newpriority, PRI_MIN_TIMESHARE),
529 sched_user_prio(td, newpriority);
534 * Update the thread's priority when the associated process's user
538 resetpriority_thread(struct thread *td)
541 /* Only change threads with a time sharing user priority. */
542 if (td->td_priority < PRI_MIN_TIMESHARE ||
543 td->td_priority > PRI_MAX_TIMESHARE)
546 /* XXX the whole needresched thing is broken, but not silly. */
549 sched_prio(td, td->td_user_pri);
554 sched_setup(void *dummy)
558 if (sched_quantum == 0)
559 sched_quantum = SCHED_QUANTUM;
560 hogticks = 2 * sched_quantum;
562 callout_init(&roundrobin_callout, CALLOUT_MPSAFE);
564 /* Kick off timeout driven events by calling first time. */
567 /* Account for thread0. */
571 /* External interfaces start here */
573 * Very early in the boot some setup of scheduler-specific
574 * parts of proc0 and of some scheduler resources needs to be done.
582 * Set up the scheduler specific parts of proc0.
584 proc0.p_sched = NULL; /* XXX */
585 thread0.td_sched = &td_sched0;
586 td_sched0.ts_thread = &thread0;
587 td_sched0.ts_state = TSS_THREAD;
594 return runq_check(&runq) + runq_check(&runq_pcpu[PCPU_GET(cpuid)]);
596 return runq_check(&runq);
601 sched_rr_interval(void)
603 if (sched_quantum == 0)
604 sched_quantum = SCHED_QUANTUM;
605 return (sched_quantum);
609 * We adjust the priority of the current process. The priority of
610 * a process gets worse as it accumulates CPU time. The cpu usage
611 * estimator (td_estcpu) is increased here. resetpriority() will
612 * compute a different priority each time td_estcpu increases by
613 * INVERSE_ESTCPU_WEIGHT
614 * (until MAXPRI is reached). The cpu usage estimator ramps up
615 * quite quickly when the process is running (linearly), and decays
616 * away exponentially, at a rate which is proportionally slower when
617 * the system is busy. The basic principle is that the system will
618 * 90% forget that the process used a lot of CPU time in 5 * loadav
619 * seconds. This causes the system to favor processes which haven't
620 * run much recently, and to round-robin among other processes.
623 sched_clock(struct thread *td)
627 mtx_assert(&sched_lock, MA_OWNED);
631 td->td_estcpu = ESTCPULIM(td->td_estcpu + 1);
632 if ((td->td_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) {
634 resetpriority_thread(td);
639 * charge childs scheduling cpu usage to parent.
642 sched_exit(struct proc *p, struct thread *td)
645 CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d",
646 td, td->td_proc->p_comm, td->td_priority);
648 sched_exit_thread(FIRST_THREAD_IN_PROC(p), td);
652 sched_exit_thread(struct thread *td, struct thread *child)
654 struct proc *childproc = child->td_proc;
656 CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d",
657 child, childproc->p_comm, child->td_priority);
658 td->td_estcpu = ESTCPULIM(td->td_estcpu + child->td_estcpu);
659 childproc->p_estcpu = ESTCPULIM(childproc->p_estcpu +
661 if ((child->td_proc->p_flag & P_NOLOAD) == 0)
666 sched_fork(struct thread *td, struct thread *childtd)
668 sched_fork_thread(td, childtd);
672 sched_fork_thread(struct thread *td, struct thread *childtd)
674 childtd->td_estcpu = td->td_estcpu;
675 sched_newthread(childtd);
679 sched_nice(struct proc *p, int nice)
683 PROC_LOCK_ASSERT(p, MA_OWNED);
684 mtx_assert(&sched_lock, MA_OWNED);
686 FOREACH_THREAD_IN_PROC(p, td) {
688 resetpriority_thread(td);
693 sched_class(struct thread *td, int class)
695 mtx_assert(&sched_lock, MA_OWNED);
696 td->td_pri_class = class;
700 * Adjust the priority of a thread.
703 sched_priority(struct thread *td, u_char prio)
705 CTR6(KTR_SCHED, "sched_prio: %p(%s) prio %d newprio %d by %p(%s)",
706 td, td->td_proc->p_comm, td->td_priority, prio, curthread,
707 curthread->td_proc->p_comm);
709 mtx_assert(&sched_lock, MA_OWNED);
710 if (td->td_priority == prio)
712 if (TD_ON_RUNQ(td)) {
713 adjustrunqueue(td, prio);
715 td->td_priority = prio;
720 * Update a thread's priority when it is lent another thread's
724 sched_lend_prio(struct thread *td, u_char prio)
727 td->td_flags |= TDF_BORROWING;
728 sched_priority(td, prio);
732 * Restore a thread's priority when priority propagation is
733 * over. The prio argument is the minimum priority the thread
734 * needs to have to satisfy other possible priority lending
735 * requests. If the thread's regulary priority is less
736 * important than prio the thread will keep a priority boost
740 sched_unlend_prio(struct thread *td, u_char prio)
744 if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
745 td->td_base_pri <= PRI_MAX_TIMESHARE)
746 base_pri = td->td_user_pri;
748 base_pri = td->td_base_pri;
749 if (prio >= base_pri) {
750 td->td_flags &= ~TDF_BORROWING;
751 sched_prio(td, base_pri);
753 sched_lend_prio(td, prio);
757 sched_prio(struct thread *td, u_char prio)
761 /* First, update the base priority. */
762 td->td_base_pri = prio;
765 * If the thread is borrowing another thread's priority, don't ever
766 * lower the priority.
768 if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
771 /* Change the real priority. */
772 oldprio = td->td_priority;
773 sched_priority(td, prio);
776 * If the thread is on a turnstile, then let the turnstile update
779 if (TD_ON_LOCK(td) && oldprio != prio)
780 turnstile_adjust(td, oldprio);
784 sched_user_prio(struct thread *td, u_char prio)
788 td->td_base_user_pri = prio;
789 if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio)
791 oldprio = td->td_user_pri;
792 td->td_user_pri = prio;
794 if (TD_ON_UPILOCK(td) && oldprio != prio)
795 umtx_pi_adjust(td, oldprio);
799 sched_lend_user_prio(struct thread *td, u_char prio)
803 td->td_flags |= TDF_UBORROWING;
805 oldprio = td->td_user_pri;
806 td->td_user_pri = prio;
808 if (TD_ON_UPILOCK(td) && oldprio != prio)
809 umtx_pi_adjust(td, oldprio);
813 sched_unlend_user_prio(struct thread *td, u_char prio)
817 base_pri = td->td_base_user_pri;
818 if (prio >= base_pri) {
819 td->td_flags &= ~TDF_UBORROWING;
820 sched_user_prio(td, base_pri);
822 sched_lend_user_prio(td, prio);
826 sched_sleep(struct thread *td)
829 mtx_assert(&sched_lock, MA_OWNED);
834 sched_switch(struct thread *td, struct thread *newtd, int flags)
842 mtx_assert(&sched_lock, MA_OWNED);
844 if ((p->p_flag & P_NOLOAD) == 0)
848 * We are volunteering to switch out so we get to nominate
849 * a successor for the rest of our quantum
850 * First try another thread in our process
852 * this is too expensive to do without per process run queues
853 * so skip it for now.
854 * XXX keep this comment as a marker.
856 if (sched_followon &&
857 (p->p_flag & P_HADTHREADS) &&
864 newtd->td_flags |= (td->td_flags & TDF_NEEDRESCHED);
866 td->td_lastcpu = td->td_oncpu;
867 td->td_flags &= ~TDF_NEEDRESCHED;
868 td->td_owepreempt = 0;
869 td->td_oncpu = NOCPU;
871 * At the last moment, if this thread is still marked RUNNING,
872 * then put it back on the run queue as it has not been suspended
873 * or stopped or any thing else similar. We never put the idle
874 * threads on the run queue, however.
876 if (td == PCPU_GET(idlethread))
879 if (TD_IS_RUNNING(td)) {
880 /* Put us back on the run queue. */
881 setrunqueue(td, (flags & SW_PREEMPT) ?
882 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
883 SRQ_OURSELF|SRQ_YIELDING);
888 * The thread we are about to run needs to be counted
889 * as if it had been added to the run queue and selected.
895 KASSERT((newtd->td_inhibitors == 0),
896 ("trying to run inhibitted thread"));
897 newtd->td_sched->ts_flags |= TSF_DIDRUN;
898 TD_SET_RUNNING(newtd);
899 if ((newtd->td_proc->p_flag & P_NOLOAD) == 0)
902 newtd = choosethread();
907 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
908 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
911 cpu_switch(td, newtd);
913 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
914 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
918 sched_lock.mtx_lock = (uintptr_t)td;
919 td->td_oncpu = PCPU_GET(cpuid);
923 sched_wakeup(struct thread *td)
925 mtx_assert(&sched_lock, MA_OWNED);
926 if (td->td_slptime > 1) {
931 setrunqueue(td, SRQ_BORING);
935 /* enable HTT_2 if you have a 2-way HTT cpu.*/
937 forward_wakeup(int cpunum)
939 cpumask_t map, me, dontuse;
944 mtx_assert(&sched_lock, MA_OWNED);
946 CTR0(KTR_RUNQ, "forward_wakeup()");
948 if ((!forward_wakeup_enabled) ||
949 (forward_wakeup_use_mask == 0 && forward_wakeup_use_loop == 0))
951 if (!smp_started || cold || panicstr)
954 forward_wakeups_requested++;
957 * check the idle mask we received against what we calculated before
958 * in the old version.
960 me = PCPU_GET(cpumask);
962 * don't bother if we should be doing it ourself..
964 if ((me & idle_cpus_mask) && (cpunum == NOCPU || me == (1 << cpunum)))
967 dontuse = me | stopped_cpus | hlt_cpus_mask;
969 if (forward_wakeup_use_loop) {
970 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
972 if ( (id & dontuse) == 0 &&
973 pc->pc_curthread == pc->pc_idlethread) {
979 if (forward_wakeup_use_mask) {
981 map = idle_cpus_mask & ~dontuse;
983 /* If they are both on, compare and use loop if different */
984 if (forward_wakeup_use_loop) {
986 printf("map (%02X) != map3 (%02X)\n",
994 /* If we only allow a specific CPU, then mask off all the others */
995 if (cpunum != NOCPU) {
996 KASSERT((cpunum <= mp_maxcpus),("forward_wakeup: bad cpunum."));
997 map &= (1 << cpunum);
999 /* Try choose an idle die. */
1000 if (forward_wakeup_use_htt) {
1001 map2 = (map & (map >> 1)) & 0x5555;
1007 /* set only one bit */
1008 if (forward_wakeup_use_single) {
1009 map = map & ((~map) + 1);
1013 forward_wakeups_delivered++;
1014 ipi_selected(map, IPI_AST);
1017 if (cpunum == NOCPU)
1018 printf("forward_wakeup: Idle processor not found\n");
1024 static void kick_other_cpu(int pri,int cpuid);
1027 kick_other_cpu(int pri,int cpuid)
1029 struct pcpu * pcpu = pcpu_find(cpuid);
1030 int cpri = pcpu->pc_curthread->td_priority;
1032 if (idle_cpus_mask & pcpu->pc_cpumask) {
1033 forward_wakeups_delivered++;
1034 ipi_selected(pcpu->pc_cpumask, IPI_AST);
1041 #if defined(IPI_PREEMPTION) && defined(PREEMPTION)
1042 #if !defined(FULL_PREEMPTION)
1043 if (pri <= PRI_MAX_ITHD)
1044 #endif /* ! FULL_PREEMPTION */
1046 ipi_selected(pcpu->pc_cpumask, IPI_PREEMPT);
1049 #endif /* defined(IPI_PREEMPTION) && defined(PREEMPTION) */
1051 pcpu->pc_curthread->td_flags |= TDF_NEEDRESCHED;
1052 ipi_selected( pcpu->pc_cpumask , IPI_AST);
1058 sched_add(struct thread *td, int flags)
1061 struct td_sched *ts;
1067 mtx_assert(&sched_lock, MA_OWNED);
1068 KASSERT(ts->ts_state != TSS_ONRUNQ,
1069 ("sched_add: td_sched %p (%s) already in run queue", ts,
1070 td->td_proc->p_comm));
1071 KASSERT(td->td_proc->p_sflag & PS_INMEM,
1072 ("sched_add: process swapped out"));
1073 CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)",
1074 td, td->td_proc->p_comm, td->td_priority, curthread,
1075 curthread->td_proc->p_comm);
1078 if (td->td_pinned != 0) {
1079 cpu = td->td_lastcpu;
1080 ts->ts_runq = &runq_pcpu[cpu];
1083 "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td, cpu);
1084 } else if ((ts)->ts_flags & TSF_BOUND) {
1085 /* Find CPU from bound runq */
1086 KASSERT(SKE_RUNQ_PCPU(ts),("sched_add: bound td_sched not on cpu runq"));
1087 cpu = ts->ts_runq - &runq_pcpu[0];
1090 "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td, cpu);
1093 "sched_add: adding td_sched:%p (td:%p) to gbl runq", ts, td);
1095 ts->ts_runq = &runq;
1098 if (single_cpu && (cpu != PCPU_GET(cpuid))) {
1099 kick_other_cpu(td->td_priority,cpu);
1103 cpumask_t me = PCPU_GET(cpumask);
1104 int idle = idle_cpus_mask & me;
1106 if (!idle && ((flags & SRQ_INTR) == 0) &&
1107 (idle_cpus_mask & ~(hlt_cpus_mask | me)))
1108 forwarded = forward_wakeup(cpu);
1112 if ((flags & SRQ_YIELDING) == 0 && maybe_preempt(td))
1119 if ((td->td_proc->p_flag & P_NOLOAD) == 0)
1121 runq_add(ts->ts_runq, ts, flags);
1122 ts->ts_state = TSS_ONRUNQ;
1126 struct td_sched *ts;
1128 mtx_assert(&sched_lock, MA_OWNED);
1129 KASSERT(ts->ts_state != TSS_ONRUNQ,
1130 ("sched_add: td_sched %p (%s) already in run queue", ts,
1131 td->td_proc->p_comm));
1132 KASSERT(td->td_proc->p_sflag & PS_INMEM,
1133 ("sched_add: process swapped out"));
1134 CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)",
1135 td, td->td_proc->p_comm, td->td_priority, curthread,
1136 curthread->td_proc->p_comm);
1137 CTR2(KTR_RUNQ, "sched_add: adding td_sched:%p (td:%p) to runq", ts, td);
1138 ts->ts_runq = &runq;
1141 * If we are yielding (on the way out anyhow)
1142 * or the thread being saved is US,
1143 * then don't try be smart about preemption
1144 * or kicking off another CPU
1145 * as it won't help and may hinder.
1146 * In the YIEDLING case, we are about to run whoever is
1147 * being put in the queue anyhow, and in the
1148 * OURSELF case, we are puting ourself on the run queue
1149 * which also only happens when we are about to yield.
1151 if((flags & SRQ_YIELDING) == 0) {
1152 if (maybe_preempt(td))
1155 if ((td->td_proc->p_flag & P_NOLOAD) == 0)
1157 runq_add(ts->ts_runq, ts, flags);
1158 ts->ts_state = TSS_ONRUNQ;
1164 sched_rem(struct thread *td)
1166 struct td_sched *ts;
1169 KASSERT(td->td_proc->p_sflag & PS_INMEM,
1170 ("sched_rem: process swapped out"));
1171 KASSERT((ts->ts_state == TSS_ONRUNQ),
1172 ("sched_rem: thread not on run queue"));
1173 mtx_assert(&sched_lock, MA_OWNED);
1174 CTR5(KTR_SCHED, "sched_rem: %p(%s) prio %d by %p(%s)",
1175 td, td->td_proc->p_comm, td->td_priority, curthread,
1176 curthread->td_proc->p_comm);
1178 if ((td->td_proc->p_flag & P_NOLOAD) == 0)
1180 runq_remove(ts->ts_runq, ts);
1182 ts->ts_state = TSS_THREAD;
1186 * Select threads to run.
1187 * Notice that the running threads still consume a slot.
1192 struct td_sched *ts;
1196 struct td_sched *kecpu;
1199 ts = runq_choose(&runq);
1200 kecpu = runq_choose(&runq_pcpu[PCPU_GET(cpuid)]);
1204 kecpu->ts_thread->td_priority < ts->ts_thread->td_priority)) {
1205 CTR2(KTR_RUNQ, "choosing td_sched %p from pcpu runq %d", kecpu,
1208 rq = &runq_pcpu[PCPU_GET(cpuid)];
1210 CTR1(KTR_RUNQ, "choosing td_sched %p from main runq", ts);
1215 ts = runq_choose(&runq);
1219 runq_remove(rq, ts);
1220 ts->ts_state = TSS_THREAD;
1222 KASSERT(ts->ts_thread->td_proc->p_sflag & PS_INMEM,
1223 ("sched_choose: process swapped out"));
1229 sched_userret(struct thread *td)
1232 * XXX we cheat slightly on the locking here to avoid locking in
1233 * the usual case. Setting td_priority here is essentially an
1234 * incomplete workaround for not setting it properly elsewhere.
1235 * Now that some interrupt handlers are threads, not setting it
1236 * properly elsewhere can clobber it in the window between setting
1237 * it here and returning to user mode, so don't waste time setting
1238 * it perfectly here.
1240 KASSERT((td->td_flags & TDF_BORROWING) == 0,
1241 ("thread with borrowed priority returning to userland"));
1242 if (td->td_priority != td->td_user_pri) {
1243 mtx_lock_spin(&sched_lock);
1244 td->td_priority = td->td_user_pri;
1245 td->td_base_pri = td->td_user_pri;
1246 mtx_unlock_spin(&sched_lock);
1251 sched_bind(struct thread *td, int cpu)
1253 struct td_sched *ts;
1255 mtx_assert(&sched_lock, MA_OWNED);
1256 KASSERT(TD_IS_RUNNING(td),
1257 ("sched_bind: cannot bind non-running thread"));
1261 ts->ts_flags |= TSF_BOUND;
1263 ts->ts_runq = &runq_pcpu[cpu];
1264 if (PCPU_GET(cpuid) == cpu)
1267 ts->ts_state = TSS_THREAD;
1269 mi_switch(SW_VOL, NULL);
1274 sched_unbind(struct thread* td)
1276 mtx_assert(&sched_lock, MA_OWNED);
1277 td->td_sched->ts_flags &= ~TSF_BOUND;
1281 sched_is_bound(struct thread *td)
1283 mtx_assert(&sched_lock, MA_OWNED);
1284 return (td->td_sched->ts_flags & TSF_BOUND);
1288 sched_relinquish(struct thread *td)
1290 mtx_lock_spin(&sched_lock);
1291 if (td->td_pri_class == PRI_TIMESHARE)
1292 sched_prio(td, PRI_MAX_TIMESHARE);
1293 mi_switch(SW_VOL, NULL);
1294 mtx_unlock_spin(&sched_lock);
1300 return (sched_tdcnt);
1304 sched_sizeof_proc(void)
1306 return (sizeof(struct proc));
1310 sched_sizeof_thread(void)
1312 return (sizeof(struct thread) + sizeof(struct td_sched));
1316 sched_pctcpu(struct thread *td)
1318 struct td_sched *ts;
1321 return (ts->ts_pctcpu);
1328 #define KERN_SWITCH_INCLUDE 1
1329 #include "kern/kern_switch.c"