2 * Copyright (c) 2012 The DragonFly Project. All rights reserved.
3 * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org>. All rights reserved.
5 * This code is derived from software contributed to The DragonFly Project
6 * by Matthew Dillon <dillon@backplane.com>,
7 * by Mihai Carabas <mihai.carabas@gmail.com>
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
20 * 3. Neither the name of The DragonFly Project nor the names of its
21 * contributors may be used to endorse or promote products derived
22 * from this software without specific, prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
27 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
28 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
30 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
31 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
32 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
33 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
34 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/kernel.h>
41 #include <sys/queue.h>
43 #include <sys/rtprio.h>
45 #include <sys/sysctl.h>
46 #include <sys/resourcevar.h>
47 #include <sys/spinlock.h>
48 #include <sys/cpu_topology.h>
49 #include <sys/thread2.h>
50 #include <sys/spinlock2.h>
51 #include <sys/mplock2.h>
55 #include <machine/cpu.h>
56 #include <machine/smp.h>
59 * Priorities. Note that with 32 run queues per scheduler each queue
60 * represents four priority levels.
66 #define PRIMASK (MAXPRI - 1)
67 #define PRIBASE_REALTIME 0
68 #define PRIBASE_NORMAL MAXPRI
69 #define PRIBASE_IDLE (MAXPRI * 2)
70 #define PRIBASE_THREAD (MAXPRI * 3)
71 #define PRIBASE_NULL (MAXPRI * 4)
73 #define NQS 32 /* 32 run queues. */
74 #define PPQ (MAXPRI / NQS) /* priorities per queue */
75 #define PPQMASK (PPQ - 1)
78 * NICEPPQ - number of nice units per priority queue
79 * ESTCPUPPQ - number of estcpu units per priority queue
80 * ESTCPUMAX - number of estcpu units
84 #define ESTCPUMAX (ESTCPUPPQ * NQS)
85 #define BATCHMAX (ESTCPUFREQ * 30)
86 #define PRIO_RANGE (PRIO_MAX - PRIO_MIN + 1)
88 #define ESTCPULIM(v) min((v), ESTCPUMAX)
92 #define lwp_priority lwp_usdata.dfly.priority
93 #define lwp_forked lwp_usdata.dfly.forked
94 #define lwp_rqindex lwp_usdata.dfly.rqindex
95 #define lwp_estcpu lwp_usdata.dfly.estcpu
96 #define lwp_estfast lwp_usdata.dfly.estfast
97 #define lwp_uload lwp_usdata.dfly.uload
98 #define lwp_rqtype lwp_usdata.dfly.rqtype
99 #define lwp_qcpu lwp_usdata.dfly.qcpu
100 #define lwp_rrcount lwp_usdata.dfly.rrcount
102 struct usched_dfly_pcpu {
103 struct spinlock spin;
104 struct thread helper_thread;
109 struct lwp *uschedcp;
110 struct rq queues[NQS];
111 struct rq rtqueues[NQS];
112 struct rq idqueues[NQS];
114 u_int32_t rtqueuebits;
115 u_int32_t idqueuebits;
122 typedef struct usched_dfly_pcpu *dfly_pcpu_t;
124 static void dfly_acquire_curproc(struct lwp *lp);
125 static void dfly_release_curproc(struct lwp *lp);
126 static void dfly_select_curproc(globaldata_t gd);
127 static void dfly_setrunqueue(struct lwp *lp);
128 static void dfly_setrunqueue_dd(dfly_pcpu_t rdd, struct lwp *lp);
129 static void dfly_schedulerclock(struct lwp *lp, sysclock_t period,
131 static void dfly_recalculate_estcpu(struct lwp *lp);
132 static void dfly_resetpriority(struct lwp *lp);
133 static void dfly_forking(struct lwp *plp, struct lwp *lp);
134 static void dfly_exiting(struct lwp *lp, struct proc *);
135 static void dfly_uload_update(struct lwp *lp);
136 static void dfly_yield(struct lwp *lp);
137 static void dfly_changeqcpu_locked(struct lwp *lp,
138 dfly_pcpu_t dd, dfly_pcpu_t rdd);
139 static dfly_pcpu_t dfly_choose_best_queue(struct lwp *lp);
140 static dfly_pcpu_t dfly_choose_worst_queue(dfly_pcpu_t dd);
141 static dfly_pcpu_t dfly_choose_queue_simple(dfly_pcpu_t dd, struct lwp *lp);
142 static void dfly_need_user_resched_remote(void *dummy);
143 static struct lwp *dfly_chooseproc_locked(dfly_pcpu_t rdd, dfly_pcpu_t dd,
144 struct lwp *chklp, int worst);
145 static void dfly_remrunqueue_locked(dfly_pcpu_t dd, struct lwp *lp);
146 static void dfly_setrunqueue_locked(dfly_pcpu_t dd, struct lwp *lp);
147 static void dfly_changedcpu(struct lwp *lp);
149 struct usched usched_dfly = {
151 "dfly", "Original DragonFly Scheduler",
152 NULL, /* default registration */
153 NULL, /* default deregistration */
154 dfly_acquire_curproc,
155 dfly_release_curproc,
158 dfly_recalculate_estcpu,
163 NULL, /* setcpumask not supported */
169 * We have NQS (32) run queues per scheduling class. For the normal
170 * class, there are 128 priorities scaled onto these 32 queues. New
171 * processes are added to the last entry in each queue, and processes
172 * are selected for running by taking them from the head and maintaining
173 * a simple FIFO arrangement. Realtime and Idle priority processes have
174 * and explicit 0-31 priority which maps directly onto their class queue
175 * index. When a queue has something in it, the corresponding bit is
176 * set in the queuebits variable, allowing a single read to determine
177 * the state of all 32 queues and then a ffs() to find the first busy
180 /* currently running a user process */
181 static cpumask_t dfly_curprocmask = CPUMASK_INITIALIZER_ALLONES;
182 static cpumask_t dfly_rdyprocmask; /* ready to accept a user process */
183 static volatile int dfly_scancpu;
184 static volatile int dfly_ucount; /* total running on whole system */
185 static struct usched_dfly_pcpu dfly_pcpu[MAXCPU];
186 static struct sysctl_ctx_list usched_dfly_sysctl_ctx;
187 static struct sysctl_oid *usched_dfly_sysctl_tree;
189 /* Debug info exposed through debug.* sysctl */
191 static int usched_dfly_debug = -1;
192 SYSCTL_INT(_debug, OID_AUTO, dfly_scdebug, CTLFLAG_RW,
193 &usched_dfly_debug, 0,
194 "Print debug information for this pid");
196 static int usched_dfly_pid_debug = -1;
197 SYSCTL_INT(_debug, OID_AUTO, dfly_pid_debug, CTLFLAG_RW,
198 &usched_dfly_pid_debug, 0,
199 "Print KTR debug information for this pid");
201 static int usched_dfly_chooser = 0;
202 SYSCTL_INT(_debug, OID_AUTO, dfly_chooser, CTLFLAG_RW,
203 &usched_dfly_chooser, 0,
204 "Print KTR debug information for this pid");
207 * Tunning usched_dfly - configurable through kern.usched_dfly.
209 * weight1 - Tries to keep threads on their current cpu. If you
210 * make this value too large the scheduler will not be
211 * able to load-balance large loads.
213 * weight2 - If non-zero, detects thread pairs undergoing synchronous
214 * communications and tries to move them closer together.
215 * Behavior is adjusted by bit 4 of features (0x10).
217 * WARNING! Weight2 is a ridiculously sensitive parameter,
218 * a small value is recommended.
220 * weight3 - Weighting based on the number of recently runnable threads
221 * on the userland scheduling queue (ignoring their loads).
222 * A nominal value here prevents high-priority (low-load)
223 * threads from accumulating on one cpu core when other
224 * cores are available.
226 * This value should be left fairly small relative to weight1
229 * weight4 - Weighting based on other cpu queues being available
230 * or running processes with higher lwp_priority's.
232 * This allows a thread to migrate to another nearby cpu if it
233 * is unable to run on the current cpu based on the other cpu
234 * being idle or running a lower priority (higher lwp_priority)
235 * thread. This value should be large enough to override weight1
237 * features - These flags can be set or cleared to enable or disable various
240 * 0x01 Enable idle-cpu pulling (default)
241 * 0x02 Enable proactive pushing (default)
242 * 0x04 Enable rebalancing rover (default)
243 * 0x08 Enable more proactive pushing (default)
244 * 0x10 (flip weight2 limit on same cpu) (default)
245 * 0x20 choose best cpu for forked process
246 * 0x40 choose current cpu for forked process
247 * 0x80 choose random cpu for forked process (default)
249 static int usched_dfly_smt = 0;
250 static int usched_dfly_cache_coherent = 0;
251 static int usched_dfly_weight1 = 200; /* keep thread on current cpu */
252 static int usched_dfly_weight2 = 180; /* synchronous peer's current cpu */
253 static int usched_dfly_weight3 = 40; /* number of threads on queue */
254 static int usched_dfly_weight4 = 160; /* availability of idle cores */
255 static int usched_dfly_features = 0x8F; /* allow pulls */
256 static int usched_dfly_fast_resched = 0;/* delta priority / resched */
257 static int usched_dfly_swmask = ~PPQMASK; /* allow pulls */
258 static int usched_dfly_rrinterval = (ESTCPUFREQ + 9) / 10;
259 static int usched_dfly_decay = 8;
261 /* KTR debug printings */
263 KTR_INFO_MASTER(usched);
265 #if !defined(KTR_USCHED_DFLY)
266 #define KTR_USCHED_DFLY KTR_ALL
269 KTR_INFO(KTR_USCHED_DFLY, usched, chooseproc, 0,
270 "USCHED_DFLY(chooseproc: pid %d, old_cpuid %d, curr_cpuid %d)",
271 pid_t pid, int old_cpuid, int curr);
274 * This function is called when the kernel intends to return to userland.
275 * It is responsible for making the thread the current designated userland
276 * thread for this cpu, blocking if necessary.
278 * The kernel will not depress our LWKT priority until after we return,
279 * in case we have to shove over to another cpu.
281 * We must determine our thread's disposition before we switch away. This
282 * is very sensitive code.
284 * WARNING! THIS FUNCTION IS ALLOWED TO CAUSE THE CURRENT THREAD TO MIGRATE
285 * TO ANOTHER CPU! Because most of the kernel assumes that no migration will
286 * occur, this function is called only under very controlled circumstances.
289 dfly_acquire_curproc(struct lwp *lp)
298 * Make sure we aren't sitting on a tsleep queue.
301 crit_enter_quick(td);
302 if (td->td_flags & TDF_TSLEEPQ)
304 dfly_recalculate_estcpu(lp);
307 dd = &dfly_pcpu[gd->gd_cpuid];
310 * Process any pending interrupts/ipi's, then handle reschedule
311 * requests. dfly_release_curproc() will try to assign a new
312 * uschedcp that isn't us and otherwise NULL it out.
315 if ((td->td_mpflags & TDF_MP_BATCH_DEMARC) &&
316 lp->lwp_rrcount >= usched_dfly_rrinterval / 2) {
320 if (user_resched_wanted()) {
321 if (dd->uschedcp == lp)
323 clear_user_resched();
324 dfly_release_curproc(lp);
328 * Loop until we are the current user thread.
330 * NOTE: dd spinlock not held at top of loop.
332 if (dd->uschedcp == lp)
335 while (dd->uschedcp != lp) {
338 spin_lock(&dd->spin);
341 (usched_dfly_features & 0x08) &&
342 (rdd = dfly_choose_best_queue(lp)) != dd) {
344 * We are not or are no longer the current lwp and a
345 * forced reschedule was requested. Figure out the
346 * best cpu to run on (our current cpu will be given
347 * significant weight).
349 * (if a reschedule was not requested we want to
350 * move this step after the uschedcp tests).
352 dfly_changeqcpu_locked(lp, dd, rdd);
353 spin_unlock(&dd->spin);
354 lwkt_deschedule(lp->lwp_thread);
355 dfly_setrunqueue_dd(rdd, lp);
358 dd = &dfly_pcpu[gd->gd_cpuid];
363 * Either no reschedule was requested or the best queue was
364 * dd, and no current process has been selected. We can
365 * trivially become the current lwp on the current cpu.
367 if (dd->uschedcp == NULL) {
368 atomic_clear_int(&lp->lwp_thread->td_mpflags,
370 ATOMIC_CPUMASK_ORBIT(dfly_curprocmask, gd->gd_cpuid);
372 dd->upri = lp->lwp_priority;
373 KKASSERT(lp->lwp_qcpu == dd->cpuid);
374 spin_unlock(&dd->spin);
379 * Put us back on the same run queue unconditionally.
381 * Set rrinterval to force placement at end of queue.
382 * Select the worst queue to ensure we round-robin,
383 * but do not change estcpu.
385 if (lp->lwp_thread->td_mpflags & TDF_MP_DIDYIELD) {
388 switch(lp->lwp_rqtype) {
389 case RTP_PRIO_NORMAL:
390 tsqbits = dd->queuebits;
391 spin_unlock(&dd->spin);
393 lp->lwp_rrcount = usched_dfly_rrinterval;
395 lp->lwp_rqindex = bsrl(tsqbits);
398 spin_unlock(&dd->spin);
401 lwkt_deschedule(lp->lwp_thread);
402 dfly_setrunqueue_dd(dd, lp);
403 atomic_clear_int(&lp->lwp_thread->td_mpflags,
407 dd = &dfly_pcpu[gd->gd_cpuid];
412 * Can we steal the current designated user thread?
414 * If we do the other thread will stall when it tries to
415 * return to userland, possibly rescheduling elsewhere.
417 * It is important to do a masked test to avoid the edge
418 * case where two near-equal-priority threads are constantly
419 * interrupting each other.
421 * In the exact match case another thread has already gained
422 * uschedcp and lowered its priority, if we steal it the
423 * other thread will stay stuck on the LWKT runq and not
424 * push to another cpu. So don't steal on equal-priority even
425 * though it might appear to be more beneficial due to not
426 * having to switch back to the other thread's context.
428 * usched_dfly_fast_resched requires that two threads be
429 * significantly far apart in priority in order to interrupt.
431 * If better but not sufficiently far apart, the current
432 * uschedcp will be interrupted at the next scheduler clock.
435 (dd->upri & ~PPQMASK) >
436 (lp->lwp_priority & ~PPQMASK) + usched_dfly_fast_resched) {
438 dd->upri = lp->lwp_priority;
439 KKASSERT(lp->lwp_qcpu == dd->cpuid);
440 spin_unlock(&dd->spin);
444 * We are not the current lwp, figure out the best cpu
445 * to run on (our current cpu will be given significant
446 * weight). Loop on cpu change.
448 if ((usched_dfly_features & 0x02) &&
449 force_resched == 0 &&
450 (rdd = dfly_choose_best_queue(lp)) != dd) {
451 dfly_changeqcpu_locked(lp, dd, rdd);
452 spin_unlock(&dd->spin);
453 lwkt_deschedule(lp->lwp_thread);
454 dfly_setrunqueue_dd(rdd, lp);
457 dd = &dfly_pcpu[gd->gd_cpuid];
462 * We cannot become the current lwp, place the lp on the
463 * run-queue of this or another cpu and deschedule ourselves.
465 * When we are reactivated we will have another chance.
467 * Reload after a switch or setrunqueue/switch possibly
468 * moved us to another cpu.
470 spin_unlock(&dd->spin);
471 lwkt_deschedule(lp->lwp_thread);
472 dfly_setrunqueue_dd(dd, lp);
475 dd = &dfly_pcpu[gd->gd_cpuid];
479 * Make sure upri is synchronized, then yield to LWKT threads as
480 * needed before returning. This could result in another reschedule.
485 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0);
489 * DFLY_RELEASE_CURPROC
491 * This routine detaches the current thread from the userland scheduler,
492 * usually because the thread needs to run or block in the kernel (at
493 * kernel priority) for a while.
495 * This routine is also responsible for selecting a new thread to
496 * make the current thread.
498 * NOTE: This implementation differs from the dummy example in that
499 * dfly_select_curproc() is able to select the current process, whereas
500 * dummy_select_curproc() is not able to select the current process.
501 * This means we have to NULL out uschedcp.
503 * Additionally, note that we may already be on a run queue if releasing
504 * via the lwkt_switch() in dfly_setrunqueue().
507 dfly_release_curproc(struct lwp *lp)
509 globaldata_t gd = mycpu;
510 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid];
513 * Make sure td_wakefromcpu is defaulted. This will be overwritten
516 if (dd->uschedcp == lp) {
517 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0);
518 spin_lock(&dd->spin);
519 if (dd->uschedcp == lp) {
520 dd->uschedcp = NULL; /* don't let lp be selected */
521 dd->upri = PRIBASE_NULL;
522 ATOMIC_CPUMASK_NANDBIT(dfly_curprocmask, gd->gd_cpuid);
523 spin_unlock(&dd->spin);
524 dfly_select_curproc(gd);
526 spin_unlock(&dd->spin);
532 * DFLY_SELECT_CURPROC
534 * Select a new current process for this cpu and clear any pending user
535 * reschedule request. The cpu currently has no current process.
537 * This routine is also responsible for equal-priority round-robining,
538 * typically triggered from dfly_schedulerclock(). In our dummy example
539 * all the 'user' threads are LWKT scheduled all at once and we just
540 * call lwkt_switch().
542 * The calling process is not on the queue and cannot be selected.
546 dfly_select_curproc(globaldata_t gd)
548 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid];
550 int cpuid = gd->gd_cpuid;
554 spin_lock(&dd->spin);
555 nlp = dfly_chooseproc_locked(dd, dd, dd->uschedcp, 0);
558 ATOMIC_CPUMASK_ORBIT(dfly_curprocmask, cpuid);
559 dd->upri = nlp->lwp_priority;
562 dd->rrcount = 0; /* reset round robin */
564 spin_unlock(&dd->spin);
565 lwkt_acquire(nlp->lwp_thread);
566 lwkt_schedule(nlp->lwp_thread);
568 spin_unlock(&dd->spin);
574 * Place the specified lwp on the user scheduler's run queue. This routine
575 * must be called with the thread descheduled. The lwp must be runnable.
576 * It must not be possible for anyone else to explicitly schedule this thread.
578 * The thread may be the current thread as a special case.
581 dfly_setrunqueue(struct lwp *lp)
587 * First validate the process LWKT state.
589 KASSERT(lp->lwp_stat == LSRUN, ("setrunqueue: lwp not LSRUN"));
590 KASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0,
591 ("lwp %d/%d already on runq! flag %08x/%08x", lp->lwp_proc->p_pid,
592 lp->lwp_tid, lp->lwp_proc->p_flags, lp->lwp_flags));
593 KKASSERT((lp->lwp_thread->td_flags & TDF_RUNQ) == 0);
596 * NOTE: dd/rdd do not necessarily represent the current cpu.
597 * Instead they may represent the cpu the thread was last
598 * scheduled on or inherited by its parent.
600 dd = &dfly_pcpu[lp->lwp_qcpu];
604 * This process is not supposed to be scheduled anywhere or assigned
605 * as the current process anywhere. Assert the condition.
607 KKASSERT(rdd->uschedcp != lp);
610 * Ok, we have to setrunqueue some target cpu and request a reschedule
613 * We have to choose the best target cpu. It might not be the current
614 * target even if the current cpu has no running user thread (for
615 * example, because the current cpu might be a hyperthread and its
616 * sibling has a thread assigned).
618 * If we just forked it is most optimal to run the child on the same
619 * cpu just in case the parent decides to wait for it (thus getting
620 * off that cpu). As long as there is nothing else runnable on the
621 * cpu, that is. If we did this unconditionally a parent forking
622 * multiple children before waiting (e.g. make -j N) leaves other
623 * cpus idle that could be working.
625 if (lp->lwp_forked) {
627 if (usched_dfly_features & 0x20)
628 rdd = dfly_choose_best_queue(lp);
629 else if (usched_dfly_features & 0x40)
630 rdd = &dfly_pcpu[lp->lwp_qcpu];
631 else if (usched_dfly_features & 0x80)
632 rdd = dfly_choose_queue_simple(rdd, lp);
633 else if (dfly_pcpu[lp->lwp_qcpu].runqcount)
634 rdd = dfly_choose_best_queue(lp);
636 rdd = &dfly_pcpu[lp->lwp_qcpu];
638 rdd = dfly_choose_best_queue(lp);
639 /* rdd = &dfly_pcpu[lp->lwp_qcpu]; */
641 if (lp->lwp_qcpu != rdd->cpuid) {
642 spin_lock(&dd->spin);
643 dfly_changeqcpu_locked(lp, dd, rdd);
644 spin_unlock(&dd->spin);
646 dfly_setrunqueue_dd(rdd, lp);
650 * Change qcpu to rdd->cpuid. The dd the lp is CURRENTLY on must be
651 * spin-locked on-call. rdd does not have to be.
654 dfly_changeqcpu_locked(struct lwp *lp, dfly_pcpu_t dd, dfly_pcpu_t rdd)
656 if (lp->lwp_qcpu != rdd->cpuid) {
657 if (lp->lwp_mpflags & LWP_MP_ULOAD) {
658 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ULOAD);
659 atomic_add_int(&dd->uload, -lp->lwp_uload);
660 atomic_add_int(&dd->ucount, -1);
661 atomic_add_int(&dfly_ucount, -1);
663 lp->lwp_qcpu = rdd->cpuid;
668 * Place lp on rdd's runqueue. Nothing is locked on call. This function
669 * also performs all necessary ancillary notification actions.
672 dfly_setrunqueue_dd(dfly_pcpu_t rdd, struct lwp *lp)
677 * We might be moving the lp to another cpu's run queue, and once
678 * on the runqueue (even if it is our cpu's), another cpu can rip
681 * TDF_MIGRATING might already be set if this is part of a
682 * remrunqueue+setrunqueue sequence.
684 if ((lp->lwp_thread->td_flags & TDF_MIGRATING) == 0)
685 lwkt_giveaway(lp->lwp_thread);
687 rgd = globaldata_find(rdd->cpuid);
690 * We lose control of the lp the moment we release the spinlock
691 * after having placed it on the queue. i.e. another cpu could pick
692 * it up, or it could exit, or its priority could be further
693 * adjusted, or something like that.
695 * WARNING! rdd can point to a foreign cpu!
697 spin_lock(&rdd->spin);
698 dfly_setrunqueue_locked(rdd, lp);
701 * Potentially interrupt the currently-running thread
703 if ((rdd->upri & ~PPQMASK) <= (lp->lwp_priority & ~PPQMASK)) {
705 * Currently running thread is better or same, do not
708 spin_unlock(&rdd->spin);
709 } else if ((rdd->upri & ~PPQMASK) <= (lp->lwp_priority & ~PPQMASK) +
710 usched_dfly_fast_resched) {
712 * Currently running thread is not better, but not so bad
713 * that we need to interrupt it. Let it run for one more
717 rdd->uschedcp->lwp_rrcount < usched_dfly_rrinterval) {
718 rdd->uschedcp->lwp_rrcount = usched_dfly_rrinterval - 1;
720 spin_unlock(&rdd->spin);
721 } else if (rgd == mycpu) {
723 * We should interrupt the currently running thread, which
724 * is on the current cpu. However, if DIDYIELD is set we
725 * round-robin unconditionally and do not interrupt it.
727 spin_unlock(&rdd->spin);
728 if (rdd->uschedcp == NULL)
729 wakeup_mycpu(&rdd->helper_thread); /* XXX */
730 if ((lp->lwp_thread->td_mpflags & TDF_MP_DIDYIELD) == 0)
734 * We should interrupt the currently running thread, which
735 * is on a different cpu.
737 spin_unlock(&rdd->spin);
738 lwkt_send_ipiq(rgd, dfly_need_user_resched_remote, NULL);
743 * This routine is called from a systimer IPI. It MUST be MP-safe and
744 * the BGL IS NOT HELD ON ENTRY. This routine is called at ESTCPUFREQ on
749 dfly_schedulerclock(struct lwp *lp, sysclock_t period, sysclock_t cpstamp)
751 globaldata_t gd = mycpu;
752 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid];
755 * Spinlocks also hold a critical section so there should not be
758 KKASSERT(gd->gd_spinlocks == 0);
764 * Do we need to round-robin? We round-robin 10 times a second.
765 * This should only occur for cpu-bound batch processes.
767 if (++lp->lwp_rrcount >= usched_dfly_rrinterval) {
768 lp->lwp_thread->td_wakefromcpu = -1;
773 * Adjust estcpu upward using a real time equivalent calculation,
774 * and recalculate lp's priority.
776 lp->lwp_estcpu = ESTCPULIM(lp->lwp_estcpu + ESTCPUMAX / ESTCPUFREQ + 1);
777 dfly_resetpriority(lp);
780 * Rebalance two cpus every 8 ticks, pulling the worst thread
781 * from the worst cpu's queue into a rotating cpu number.
783 * This mechanic is needed because the push algorithms can
784 * steady-state in an non-optimal configuration. We need to mix it
785 * up a little, even if it means breaking up a paired thread, so
786 * the push algorithms can rebalance the degenerate conditions.
787 * This portion of the algorithm exists to ensure stability at the
788 * selected weightings.
790 * Because we might be breaking up optimal conditions we do not want
791 * to execute this too quickly, hence we only rebalance approximately
792 * ~7-8 times per second. The push's, on the otherhand, are capable
793 * moving threads to other cpus at a much higher rate.
795 * We choose the most heavily loaded thread from the worst queue
796 * in order to ensure that multiple heavy-weight threads on the same
797 * queue get broken up, and also because these threads are the most
798 * likely to be able to remain in place. Hopefully then any pairings,
799 * if applicable, migrate to where these threads are.
801 if ((usched_dfly_features & 0x04) &&
802 ((u_int)sched_ticks & 7) == 0 &&
803 (u_int)sched_ticks / 8 % ncpus == gd->gd_cpuid) {
810 rdd = dfly_choose_worst_queue(dd);
812 spin_lock(&dd->spin);
813 if (spin_trylock(&rdd->spin)) {
814 nlp = dfly_chooseproc_locked(rdd, dd, NULL, 1);
815 spin_unlock(&rdd->spin);
817 spin_unlock(&dd->spin);
819 spin_unlock(&dd->spin);
825 /* dd->spin held if nlp != NULL */
828 * Either schedule it or add it to our queue.
831 (nlp->lwp_priority & ~PPQMASK) < (dd->upri & ~PPQMASK)) {
832 ATOMIC_CPUMASK_ORMASK(dfly_curprocmask, dd->cpumask);
833 dd->upri = nlp->lwp_priority;
836 dd->rrcount = 0; /* reset round robin */
838 spin_unlock(&dd->spin);
839 lwkt_acquire(nlp->lwp_thread);
840 lwkt_schedule(nlp->lwp_thread);
842 dfly_setrunqueue_locked(dd, nlp);
843 spin_unlock(&dd->spin);
849 * Called from acquire and from kern_synch's one-second timer (one of the
850 * callout helper threads) with a critical section held.
852 * Adjust p_estcpu based on our single-cpu load, p_nice, and compensate for
853 * overall system load.
855 * Note that no recalculation occurs for a process which sleeps and wakes
856 * up in the same tick. That is, a system doing thousands of context
857 * switches per second will still only do serious estcpu calculations
858 * ESTCPUFREQ times per second.
862 dfly_recalculate_estcpu(struct lwp *lp)
864 globaldata_t gd = mycpu;
872 * We have to subtract periodic to get the last schedclock
873 * timeout time, otherwise we would get the upcoming timeout.
874 * Keep in mind that a process can migrate between cpus and
875 * while the scheduler clock should be very close, boundary
876 * conditions could lead to a small negative delta.
878 cpbase = gd->gd_schedclock.time - gd->gd_schedclock.periodic;
880 if (lp->lwp_slptime > 1) {
882 * Too much time has passed, do a coarse correction.
884 lp->lwp_estcpu = lp->lwp_estcpu >> 1;
885 dfly_resetpriority(lp);
886 lp->lwp_cpbase = cpbase;
889 } else if (lp->lwp_cpbase != cpbase) {
891 * Adjust estcpu if we are in a different tick. Don't waste
892 * time if we are in the same tick.
894 * First calculate the number of ticks in the measurement
895 * interval. The ttlticks calculation can wind up 0 due to
896 * a bug in the handling of lwp_slptime (as yet not found),
897 * so make sure we do not get a divide by 0 panic.
899 ttlticks = (cpbase - lp->lwp_cpbase) /
900 gd->gd_schedclock.periodic;
901 if ((ssysclock_t)ttlticks < 0) {
903 lp->lwp_cpbase = cpbase;
907 updatepcpu(lp, lp->lwp_cpticks, ttlticks);
910 * Calculate the percentage of one cpu being used then
911 * compensate for any system load in excess of ncpus.
913 * For example, if we have 8 cores and 16 running cpu-bound
914 * processes then all things being equal each process will
915 * get 50% of one cpu. We need to pump this value back
916 * up to 100% so the estcpu calculation properly adjusts
917 * the process's dynamic priority.
919 * estcpu is scaled by ESTCPUMAX, pctcpu is scaled by FSCALE.
921 estcpu = (lp->lwp_pctcpu * ESTCPUMAX) >> FSHIFT;
922 ucount = dfly_ucount;
923 if (ucount > ncpus) {
924 estcpu += estcpu * (ucount - ncpus) / ncpus;
927 if (usched_dfly_debug == lp->lwp_proc->p_pid) {
928 kprintf("pid %d lwp %p estcpu %3d %3d cp %d/%d",
929 lp->lwp_proc->p_pid, lp,
930 estcpu, lp->lwp_estcpu,
931 lp->lwp_cpticks, ttlticks);
935 * Adjust lp->lwp_esetcpu. The decay factor determines how
936 * quickly lwp_estcpu collapses to its realtime calculation.
937 * A slower collapse gives us a more accurate number over
938 * the long term but can create problems with bursty threads
939 * or threads which become cpu hogs.
941 * To solve this problem, newly started lwps and lwps which
942 * are restarting after having been asleep for a while are
943 * given a much, much faster decay in order to quickly
944 * detect whether they become cpu-bound.
946 * NOTE: p_nice is accounted for in dfly_resetpriority(),
947 * and not here, but we must still ensure that a
948 * cpu-bound nice -20 process does not completely
949 * override a cpu-bound nice +20 process.
951 * NOTE: We must use ESTCPULIM() here to deal with any
954 decay_factor = usched_dfly_decay;
955 if (decay_factor < 1)
957 if (decay_factor > 1024)
960 if (lp->lwp_estfast < usched_dfly_decay) {
962 lp->lwp_estcpu = ESTCPULIM(
963 (lp->lwp_estcpu * lp->lwp_estfast + estcpu) /
964 (lp->lwp_estfast + 1));
966 lp->lwp_estcpu = ESTCPULIM(
967 (lp->lwp_estcpu * decay_factor + estcpu) /
971 if (usched_dfly_debug == lp->lwp_proc->p_pid)
972 kprintf(" finalestcpu %d\n", lp->lwp_estcpu);
973 dfly_resetpriority(lp);
974 lp->lwp_cpbase += ttlticks * gd->gd_schedclock.periodic;
980 * Compute the priority of a process when running in user mode.
981 * Arrange to reschedule if the resulting priority is better
982 * than that of the current process.
984 * This routine may be called with any process.
986 * This routine is called by fork1() for initial setup with the process
987 * of the run queue, and also may be called normally with the process on or
991 dfly_resetpriority(struct lwp *lp)
1004 * Lock the scheduler (lp) belongs to. This can be on a different
1005 * cpu. Handle races. This loop breaks out with the appropriate
1009 rcpu = lp->lwp_qcpu;
1011 rdd = &dfly_pcpu[rcpu];
1012 spin_lock(&rdd->spin);
1013 if (rcpu == lp->lwp_qcpu)
1015 spin_unlock(&rdd->spin);
1019 * Calculate the new priority and queue type
1021 newrqtype = lp->lwp_rtprio.type;
1024 case RTP_PRIO_REALTIME:
1026 newpriority = PRIBASE_REALTIME +
1027 (lp->lwp_rtprio.prio & PRIMASK);
1029 case RTP_PRIO_NORMAL:
1033 estcpu = lp->lwp_estcpu;
1036 * p_nice piece Adds (0-40) * 2 0-80
1037 * estcpu Adds 16384 * 4 / 512 0-128
1039 newpriority = (lp->lwp_proc->p_nice - PRIO_MIN) * PPQ / NICEPPQ;
1040 newpriority += estcpu * PPQ / ESTCPUPPQ;
1041 newpriority = newpriority * MAXPRI / (PRIO_RANGE * PPQ /
1042 NICEPPQ + ESTCPUMAX * PPQ / ESTCPUPPQ);
1043 newpriority = PRIBASE_NORMAL + (newpriority & PRIMASK);
1046 newpriority = PRIBASE_IDLE + (lp->lwp_rtprio.prio & PRIMASK);
1048 case RTP_PRIO_THREAD:
1049 newpriority = PRIBASE_THREAD + (lp->lwp_rtprio.prio & PRIMASK);
1052 panic("Bad RTP_PRIO %d", newrqtype);
1057 * The LWKT scheduler doesn't dive usched structures, give it a hint
1058 * on the relative priority of user threads running in the kernel.
1059 * The LWKT scheduler will always ensure that a user thread running
1060 * in the kernel will get cpu some time, regardless of its upri,
1061 * but can decide not to instantly switch from one kernel or user
1062 * mode user thread to a kernel-mode user thread when it has a less
1063 * desireable user priority.
1065 * td_upri has normal sense (higher values are more desireable), so
1068 lp->lwp_thread->td_upri = -(newpriority & usched_dfly_swmask);
1071 * The newpriority incorporates the queue type so do a simple masked
1072 * check to determine if the process has moved to another queue. If
1073 * it has, and it is currently on a run queue, then move it.
1075 * Since uload is ~PPQMASK masked, no modifications are necessary if
1076 * we end up in the same run queue.
1078 if ((lp->lwp_priority ^ newpriority) & ~PPQMASK) {
1079 if (lp->lwp_mpflags & LWP_MP_ONRUNQ) {
1080 dfly_remrunqueue_locked(rdd, lp);
1081 lp->lwp_priority = newpriority;
1082 lp->lwp_rqtype = newrqtype;
1083 lp->lwp_rqindex = (newpriority & PRIMASK) / PPQ;
1084 dfly_setrunqueue_locked(rdd, lp);
1087 lp->lwp_priority = newpriority;
1088 lp->lwp_rqtype = newrqtype;
1089 lp->lwp_rqindex = (newpriority & PRIMASK) / PPQ;
1094 * In the same PPQ, uload cannot change.
1096 lp->lwp_priority = newpriority;
1102 * Adjust effective load.
1104 * Calculate load then scale up or down geometrically based on p_nice.
1105 * Processes niced up (positive) are less important, and processes
1106 * niced downard (negative) are more important. The higher the uload,
1107 * the more important the thread.
1109 /* 0-511, 0-100% cpu */
1110 delta_uload = lp->lwp_estcpu / NQS;
1111 delta_uload -= delta_uload * lp->lwp_proc->p_nice / (PRIO_MAX + 1);
1114 delta_uload -= lp->lwp_uload;
1115 lp->lwp_uload += delta_uload;
1116 if (lp->lwp_mpflags & LWP_MP_ULOAD)
1117 atomic_add_int(&dfly_pcpu[lp->lwp_qcpu].uload, delta_uload);
1120 * Determine if we need to reschedule the target cpu. This only
1121 * occurs if the LWP is already on a scheduler queue, which means
1122 * that idle cpu notification has already occured. At most we
1123 * need only issue a need_user_resched() on the appropriate cpu.
1125 * The LWP may be owned by a CPU different from the current one,
1126 * in which case dd->uschedcp may be modified without an MP lock
1127 * or a spinlock held. The worst that happens is that the code
1128 * below causes a spurious need_user_resched() on the target CPU
1129 * and dd->pri to be wrong for a short period of time, both of
1130 * which are harmless.
1132 * If checkpri is 0 we are adjusting the priority of the current
1133 * process, possibly higher (less desireable), so ignore the upri
1134 * check which will fail in that case.
1137 if (CPUMASK_TESTBIT(dfly_rdyprocmask, rcpu) &&
1139 (rdd->upri & ~PRIMASK) >
1140 (lp->lwp_priority & ~PRIMASK))) {
1141 if (rcpu == mycpu->gd_cpuid) {
1142 spin_unlock(&rdd->spin);
1143 need_user_resched();
1145 spin_unlock(&rdd->spin);
1146 lwkt_send_ipiq(globaldata_find(rcpu),
1147 dfly_need_user_resched_remote,
1151 spin_unlock(&rdd->spin);
1154 spin_unlock(&rdd->spin);
1161 dfly_yield(struct lwp *lp)
1163 if (lp->lwp_qcpu != mycpu->gd_cpuid)
1165 KKASSERT(lp == curthread->td_lwp);
1168 * Don't set need_user_resched() or mess with rrcount or anything.
1169 * the TDF flag will override everything as long as we release.
1171 atomic_set_int(&lp->lwp_thread->td_mpflags, TDF_MP_DIDYIELD);
1172 dfly_release_curproc(lp);
1176 * Thread was forcefully migrated to another cpu. Normally forced migrations
1177 * are used for iterations and the kernel returns to the original cpu before
1178 * returning and this is not needed. However, if the kernel migrates a
1179 * thread to another cpu and wants to leave it there, it has to call this
1182 * Note that the lwkt_migratecpu() function also released the thread, so
1183 * we don't have to worry about that.
1187 dfly_changedcpu(struct lwp *lp)
1189 dfly_pcpu_t dd = &dfly_pcpu[lp->lwp_qcpu];
1190 dfly_pcpu_t rdd = &dfly_pcpu[mycpu->gd_cpuid];
1193 spin_lock(&dd->spin);
1194 dfly_changeqcpu_locked(lp, dd, rdd);
1195 spin_unlock(&dd->spin);
1200 * Called from fork1() when a new child process is being created.
1202 * Give the child process an initial estcpu that is more batch then
1203 * its parent and dock the parent for the fork (but do not
1204 * reschedule the parent).
1208 * XXX lwp should be "spawning" instead of "forking"
1211 dfly_forking(struct lwp *plp, struct lwp *lp)
1214 * Put the child 4 queue slots (out of 32) higher than the parent
1215 * (less desireable than the parent).
1217 lp->lwp_estcpu = ESTCPULIM(plp->lwp_estcpu + ESTCPUPPQ * 4);
1219 lp->lwp_estfast = 0;
1222 * Dock the parent a cost for the fork, protecting us from fork
1223 * bombs. If the parent is forking quickly make the child more
1226 plp->lwp_estcpu = ESTCPULIM(plp->lwp_estcpu + ESTCPUPPQ / 16);
1230 * Called when a lwp is being removed from this scheduler, typically
1231 * during lwp_exit(). We have to clean out any ULOAD accounting before
1232 * we can let the lp go. The dd->spin lock is not needed for uload
1235 * Scheduler dequeueing has already occurred, no further action in that
1239 dfly_exiting(struct lwp *lp, struct proc *child_proc)
1241 dfly_pcpu_t dd = &dfly_pcpu[lp->lwp_qcpu];
1243 if (lp->lwp_mpflags & LWP_MP_ULOAD) {
1244 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ULOAD);
1245 atomic_add_int(&dd->uload, -lp->lwp_uload);
1246 atomic_add_int(&dd->ucount, -1);
1247 atomic_add_int(&dfly_ucount, -1);
1252 * This function cannot block in any way, but spinlocks are ok.
1254 * Update the uload based on the state of the thread (whether it is going
1255 * to sleep or running again). The uload is meant to be a longer-term
1256 * load and not an instantanious load.
1259 dfly_uload_update(struct lwp *lp)
1261 dfly_pcpu_t dd = &dfly_pcpu[lp->lwp_qcpu];
1263 if (lp->lwp_thread->td_flags & TDF_RUNQ) {
1264 if ((lp->lwp_mpflags & LWP_MP_ULOAD) == 0) {
1265 spin_lock(&dd->spin);
1266 if ((lp->lwp_mpflags & LWP_MP_ULOAD) == 0) {
1267 atomic_set_int(&lp->lwp_mpflags,
1269 atomic_add_int(&dd->uload, lp->lwp_uload);
1270 atomic_add_int(&dd->ucount, 1);
1271 atomic_add_int(&dfly_ucount, 1);
1273 spin_unlock(&dd->spin);
1275 } else if (lp->lwp_slptime > 0) {
1276 if (lp->lwp_mpflags & LWP_MP_ULOAD) {
1277 spin_lock(&dd->spin);
1278 if (lp->lwp_mpflags & LWP_MP_ULOAD) {
1279 atomic_clear_int(&lp->lwp_mpflags,
1281 atomic_add_int(&dd->uload, -lp->lwp_uload);
1282 atomic_add_int(&dd->ucount, -1);
1283 atomic_add_int(&dfly_ucount, -1);
1285 spin_unlock(&dd->spin);
1291 * chooseproc() is called when a cpu needs a user process to LWKT schedule,
1292 * it selects a user process and returns it. If chklp is non-NULL and chklp
1293 * has a better or equal priority then the process that would otherwise be
1294 * chosen, NULL is returned.
1296 * Until we fix the RUNQ code the chklp test has to be strict or we may
1297 * bounce between processes trying to acquire the current process designation.
1299 * Must be called with rdd->spin locked. The spinlock is left intact through
1300 * the entire routine. dd->spin does not have to be locked.
1302 * If worst is non-zero this function finds the worst thread instead of the
1303 * best thread (used by the schedulerclock-based rover).
1307 dfly_chooseproc_locked(dfly_pcpu_t rdd, dfly_pcpu_t dd,
1308 struct lwp *chklp, int worst)
1318 rtqbits = rdd->rtqueuebits;
1319 tsqbits = rdd->queuebits;
1320 idqbits = rdd->idqueuebits;
1324 pri = bsrl(idqbits);
1325 q = &rdd->idqueues[pri];
1326 which = &rdd->idqueuebits;
1327 } else if (tsqbits) {
1328 pri = bsrl(tsqbits);
1329 q = &rdd->queues[pri];
1330 which = &rdd->queuebits;
1331 } else if (rtqbits) {
1332 pri = bsrl(rtqbits);
1333 q = &rdd->rtqueues[pri];
1334 which = &rdd->rtqueuebits;
1338 lp = TAILQ_LAST(q, rq);
1341 pri = bsfl(rtqbits);
1342 q = &rdd->rtqueues[pri];
1343 which = &rdd->rtqueuebits;
1344 } else if (tsqbits) {
1345 pri = bsfl(tsqbits);
1346 q = &rdd->queues[pri];
1347 which = &rdd->queuebits;
1348 } else if (idqbits) {
1349 pri = bsfl(idqbits);
1350 q = &rdd->idqueues[pri];
1351 which = &rdd->idqueuebits;
1355 lp = TAILQ_FIRST(q);
1357 KASSERT(lp, ("chooseproc: no lwp on busy queue"));
1360 * If the passed lwp <chklp> is reasonably close to the selected
1361 * lwp <lp>, return NULL (indicating that <chklp> should be kept).
1363 * Note that we must error on the side of <chklp> to avoid bouncing
1364 * between threads in the acquire code.
1367 if (chklp->lwp_priority < lp->lwp_priority + PPQ)
1371 KTR_COND_LOG(usched_chooseproc,
1372 lp->lwp_proc->p_pid == usched_dfly_pid_debug,
1373 lp->lwp_proc->p_pid,
1374 lp->lwp_thread->td_gd->gd_cpuid,
1377 KASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) != 0, ("not on runq6!"));
1378 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ);
1379 TAILQ_REMOVE(q, lp, lwp_procq);
1382 *which &= ~(1 << pri);
1385 * If we are choosing a process from rdd with the intent to
1386 * move it to dd, lwp_qcpu must be adjusted while rdd's spinlock
1390 if (lp->lwp_mpflags & LWP_MP_ULOAD) {
1391 atomic_add_int(&rdd->uload, -lp->lwp_uload);
1392 atomic_add_int(&rdd->ucount, -1);
1393 atomic_add_int(&dfly_ucount, -1);
1395 lp->lwp_qcpu = dd->cpuid;
1396 atomic_add_int(&dd->uload, lp->lwp_uload);
1397 atomic_add_int(&dd->ucount, 1);
1398 atomic_add_int(&dfly_ucount, 1);
1399 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ULOAD);
1405 * USED TO PUSH RUNNABLE LWPS TO THE LEAST LOADED CPU.
1407 * Choose a cpu node to schedule lp on, hopefully nearby its current
1410 * We give the current node a modest advantage for obvious reasons.
1412 * We also give the node the thread was woken up FROM a slight advantage
1413 * in order to try to schedule paired threads which synchronize/block waiting
1414 * for each other fairly close to each other. Similarly in a network setting
1415 * this feature will also attempt to place a user process near the kernel
1416 * protocol thread that is feeding it data. THIS IS A CRITICAL PART of the
1417 * algorithm as it heuristically groups synchronizing processes for locality
1418 * of reference in multi-socket systems.
1420 * We check against running processes and give a big advantage if there
1423 * The caller will normally dfly_setrunqueue() lp on the returned queue.
1425 * When the topology is known choose a cpu whos group has, in aggregate,
1426 * has the lowest weighted load.
1430 dfly_choose_best_queue(struct lwp *lp)
1437 dfly_pcpu_t dd = &dfly_pcpu[lp->lwp_qcpu];
1447 * When the topology is unknown choose a random cpu that is hopefully
1450 if (dd->cpunode == NULL)
1451 return (dfly_choose_queue_simple(dd, lp));
1456 if ((wakecpu = lp->lwp_thread->td_wakefromcpu) >= 0)
1457 wakemask = dfly_pcpu[wakecpu].cpumask;
1459 CPUMASK_ASSZERO(wakemask);
1462 * When the topology is known choose a cpu whos group has, in
1463 * aggregate, has the lowest weighted load.
1465 cpup = root_cpu_node;
1470 * Degenerate case super-root
1472 if (cpup->child_no == 1) {
1473 cpup = cpup->child_node[0];
1480 if (cpup->child_no == 0) {
1481 rdd = &dfly_pcpu[BSFCPUMASK(cpup->members)];
1486 lowest_load = 0x7FFFFFFF;
1488 for (n = 0; n < cpup->child_no; ++n) {
1490 * Accumulate load information for all cpus
1491 * which are members of this node.
1493 cpun = cpup->child_node[n];
1494 mask = cpun->members;
1495 CPUMASK_ANDMASK(mask, usched_global_cpumask);
1496 CPUMASK_ANDMASK(mask, smp_active_mask);
1497 CPUMASK_ANDMASK(mask, lp->lwp_cpumask);
1498 if (CPUMASK_TESTZERO(mask))
1504 while (CPUMASK_TESTNZERO(mask)) {
1505 cpuid = BSFCPUMASK(mask);
1506 rdd = &dfly_pcpu[cpuid];
1508 load += rdd->ucount * usched_dfly_weight3;
1510 if (rdd->uschedcp == NULL &&
1511 rdd->runqcount == 0 &&
1512 globaldata_find(cpuid)->gd_tdrunqcount == 0
1514 load -= usched_dfly_weight4;
1517 else if (rdd->upri > lp->lwp_priority + PPQ) {
1518 load -= usched_dfly_weight4 / 2;
1521 CPUMASK_NANDBIT(mask, cpuid);
1526 * Compensate if the lp is already accounted for in
1527 * the aggregate uload for this mask set. We want
1528 * to calculate the loads as if lp were not present,
1529 * otherwise the calculation is bogus.
1531 if ((lp->lwp_mpflags & LWP_MP_ULOAD) &&
1532 CPUMASK_TESTMASK(dd->cpumask, cpun->members)) {
1533 load -= lp->lwp_uload;
1534 load -= usched_dfly_weight3;
1540 * Advantage the cpu group (lp) is already on.
1542 if (CPUMASK_TESTMASK(cpun->members, dd->cpumask))
1543 load -= usched_dfly_weight1;
1546 * Advantage the cpu group we want to pair (lp) to,
1547 * but don't let it go to the exact same cpu as
1548 * the wakecpu target.
1550 * We do this by checking whether cpun is a
1551 * terminal node or not. All cpun's at the same
1552 * level will either all be terminal or all not
1555 * If it is and we match we disadvantage the load.
1556 * If it is and we don't match we advantage the load.
1558 * Also note that we are effectively disadvantaging
1559 * all-but-one by the same amount, so it won't effect
1560 * the weight1 factor for the all-but-one nodes.
1562 if (CPUMASK_TESTMASK(cpun->members, wakemask)) {
1563 if (cpun->child_no != 0) {
1565 load -= usched_dfly_weight2;
1567 if (usched_dfly_features & 0x10)
1568 load += usched_dfly_weight2;
1570 load -= usched_dfly_weight2;
1575 * Calculate the best load
1577 if (cpub == NULL || lowest_load > load ||
1578 (lowest_load == load &&
1579 CPUMASK_TESTMASK(cpun->members, dd->cpumask))
1587 if (usched_dfly_chooser)
1588 kprintf("lp %02d->%02d %s\n",
1589 lp->lwp_qcpu, rdd->cpuid, lp->lwp_proc->p_comm);
1594 * USED TO PULL RUNNABLE LWPS FROM THE MOST LOADED CPU.
1596 * Choose the worst queue close to dd's cpu node with a non-empty runq
1597 * that is NOT dd. Also require that the moving of the highest-load thread
1598 * from rdd to dd does not cause the uload's to cross each other.
1600 * This is used by the thread chooser when the current cpu's queues are
1601 * empty to steal a thread from another cpu's queue. We want to offload
1602 * the most heavily-loaded queue.
1606 dfly_choose_worst_queue(dfly_pcpu_t dd)
1624 * When the topology is unknown choose a random cpu that is hopefully
1627 if (dd->cpunode == NULL) {
1632 * When the topology is known choose a cpu whos group has, in
1633 * aggregate, has the lowest weighted load.
1635 cpup = root_cpu_node;
1639 * Degenerate case super-root
1641 if (cpup->child_no == 1) {
1642 cpup = cpup->child_node[0];
1649 if (cpup->child_no == 0) {
1650 rdd = &dfly_pcpu[BSFCPUMASK(cpup->members)];
1657 for (n = 0; n < cpup->child_no; ++n) {
1659 * Accumulate load information for all cpus
1660 * which are members of this node.
1662 cpun = cpup->child_node[n];
1663 mask = cpun->members;
1664 CPUMASK_ANDMASK(mask, usched_global_cpumask);
1665 CPUMASK_ANDMASK(mask, smp_active_mask);
1666 if (CPUMASK_TESTZERO(mask))
1671 while (CPUMASK_TESTNZERO(mask)) {
1672 cpuid = BSFCPUMASK(mask);
1673 rdd = &dfly_pcpu[cpuid];
1675 load += rdd->ucount * usched_dfly_weight3;
1676 if (rdd->uschedcp == NULL &&
1677 rdd->runqcount == 0 &&
1678 globaldata_find(cpuid)->gd_tdrunqcount == 0
1680 load -= usched_dfly_weight4;
1683 else if (rdd->upri > dd->upri + PPQ) {
1684 load -= usched_dfly_weight4 / 2;
1687 CPUMASK_NANDBIT(mask, cpuid);
1693 * Prefer candidates which are somewhat closer to
1696 if (CPUMASK_TESTMASK(dd->cpumask, cpun->members))
1697 load += usched_dfly_weight1;
1700 * The best candidate is the one with the worst
1703 if (cpub == NULL || highest_load < load) {
1704 highest_load = load;
1712 * We never return our own node (dd), and only return a remote
1713 * node if it's load is significantly worse than ours (i.e. where
1714 * stealing a thread would be considered reasonable).
1716 * This also helps us avoid breaking paired threads apart which
1717 * can have disastrous effects on performance.
1724 if (rdd->rtqueuebits && hpri < (pri = bsrl(rdd->rtqueuebits)))
1726 if (rdd->queuebits && hpri < (pri = bsrl(rdd->queuebits)))
1728 if (rdd->idqueuebits && hpri < (pri = bsrl(rdd->idqueuebits)))
1731 if (rdd->uload - hpri < dd->uload + hpri)
1739 dfly_choose_queue_simple(dfly_pcpu_t dd, struct lwp *lp)
1747 * Fallback to the original heuristic, select random cpu,
1748 * first checking cpus not currently running a user thread.
1751 cpuid = (dfly_scancpu & 0xFFFF) % ncpus;
1752 mask = dfly_rdyprocmask;
1753 CPUMASK_NANDMASK(mask, dfly_curprocmask);
1754 CPUMASK_ANDMASK(mask, lp->lwp_cpumask);
1755 CPUMASK_ANDMASK(mask, smp_active_mask);
1756 CPUMASK_ANDMASK(mask, usched_global_cpumask);
1758 while (CPUMASK_TESTNZERO(mask)) {
1759 CPUMASK_ASSNBMASK(tmpmask, cpuid);
1760 if (CPUMASK_TESTMASK(tmpmask, mask)) {
1761 CPUMASK_ANDMASK(tmpmask, mask);
1762 cpuid = BSFCPUMASK(tmpmask);
1764 cpuid = BSFCPUMASK(mask);
1766 rdd = &dfly_pcpu[cpuid];
1768 if ((rdd->upri & ~PPQMASK) >= (lp->lwp_priority & ~PPQMASK))
1770 CPUMASK_NANDBIT(mask, cpuid);
1774 * Then cpus which might have a currently running lp
1776 cpuid = (dfly_scancpu & 0xFFFF) % ncpus;
1777 mask = dfly_rdyprocmask;
1778 CPUMASK_ANDMASK(mask, dfly_curprocmask);
1779 CPUMASK_ANDMASK(mask, lp->lwp_cpumask);
1780 CPUMASK_ANDMASK(mask, smp_active_mask);
1781 CPUMASK_ANDMASK(mask, usched_global_cpumask);
1783 while (CPUMASK_TESTNZERO(mask)) {
1784 CPUMASK_ASSNBMASK(tmpmask, cpuid);
1785 if (CPUMASK_TESTMASK(tmpmask, mask)) {
1786 CPUMASK_ANDMASK(tmpmask, mask);
1787 cpuid = BSFCPUMASK(tmpmask);
1789 cpuid = BSFCPUMASK(mask);
1791 rdd = &dfly_pcpu[cpuid];
1793 if ((rdd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK))
1795 CPUMASK_NANDBIT(mask, cpuid);
1799 * If we cannot find a suitable cpu we reload from dfly_scancpu
1800 * and round-robin. Other cpus will pickup as they release their
1801 * current lwps or become ready.
1803 * Avoid a degenerate system lockup case if usched_global_cpumask
1804 * is set to 0 or otherwise does not cover lwp_cpumask.
1806 * We only kick the target helper thread in this case, we do not
1807 * set the user resched flag because
1809 cpuid = (dfly_scancpu & 0xFFFF) % ncpus;
1810 if (CPUMASK_TESTBIT(usched_global_cpumask, cpuid) == 0)
1812 rdd = &dfly_pcpu[cpuid];
1819 dfly_need_user_resched_remote(void *dummy)
1821 globaldata_t gd = mycpu;
1822 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid];
1825 * Flag reschedule needed
1827 need_user_resched();
1830 * If no user thread is currently running we need to kick the helper
1831 * on our cpu to recover. Otherwise the cpu will never schedule
1834 * We cannot schedule the process ourselves because this is an
1835 * IPI callback and we cannot acquire spinlocks in an IPI callback.
1837 * Call wakeup_mycpu to avoid sending IPIs to other CPUs
1839 if (dd->uschedcp == NULL &&
1840 CPUMASK_TESTBIT(dfly_rdyprocmask, gd->gd_cpuid)) {
1841 ATOMIC_CPUMASK_NANDBIT(dfly_rdyprocmask, gd->gd_cpuid);
1842 wakeup_mycpu(&dd->helper_thread);
1847 * dfly_remrunqueue_locked() removes a given process from the run queue
1848 * that it is on, clearing the queue busy bit if it becomes empty.
1850 * Note that user process scheduler is different from the LWKT schedule.
1851 * The user process scheduler only manages user processes but it uses LWKT
1852 * underneath, and a user process operating in the kernel will often be
1853 * 'released' from our management.
1855 * uload is NOT adjusted here. It is only adjusted if the lwkt_thread goes
1856 * to sleep or the lwp is moved to a different runq.
1859 dfly_remrunqueue_locked(dfly_pcpu_t rdd, struct lwp *lp)
1865 KKASSERT(rdd->runqcount >= 0);
1867 pri = lp->lwp_rqindex;
1869 switch(lp->lwp_rqtype) {
1870 case RTP_PRIO_NORMAL:
1871 q = &rdd->queues[pri];
1872 which = &rdd->queuebits;
1874 case RTP_PRIO_REALTIME:
1876 q = &rdd->rtqueues[pri];
1877 which = &rdd->rtqueuebits;
1880 q = &rdd->idqueues[pri];
1881 which = &rdd->idqueuebits;
1884 panic("remrunqueue: invalid rtprio type");
1887 KKASSERT(lp->lwp_mpflags & LWP_MP_ONRUNQ);
1888 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ);
1889 TAILQ_REMOVE(q, lp, lwp_procq);
1891 if (TAILQ_EMPTY(q)) {
1892 KASSERT((*which & (1 << pri)) != 0,
1893 ("remrunqueue: remove from empty queue"));
1894 *which &= ~(1 << pri);
1899 * dfly_setrunqueue_locked()
1901 * Add a process whos rqtype and rqindex had previously been calculated
1902 * onto the appropriate run queue. Determine if the addition requires
1903 * a reschedule on a cpu and return the cpuid or -1.
1905 * NOTE: Lower priorities are better priorities.
1907 * NOTE ON ULOAD: This variable specifies the aggregate load on a cpu, the
1908 * sum of the rough lwp_priority for all running and runnable
1909 * processes. Lower priority processes (higher lwp_priority
1910 * values) actually DO count as more load, not less, because
1911 * these are the programs which require the most care with
1912 * regards to cpu selection.
1915 dfly_setrunqueue_locked(dfly_pcpu_t rdd, struct lwp *lp)
1921 KKASSERT(lp->lwp_qcpu == rdd->cpuid);
1923 if ((lp->lwp_mpflags & LWP_MP_ULOAD) == 0) {
1924 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ULOAD);
1925 atomic_add_int(&dfly_pcpu[lp->lwp_qcpu].uload, lp->lwp_uload);
1926 atomic_add_int(&dfly_pcpu[lp->lwp_qcpu].ucount, 1);
1927 atomic_add_int(&dfly_ucount, 1);
1930 pri = lp->lwp_rqindex;
1932 switch(lp->lwp_rqtype) {
1933 case RTP_PRIO_NORMAL:
1934 q = &rdd->queues[pri];
1935 which = &rdd->queuebits;
1937 case RTP_PRIO_REALTIME:
1939 q = &rdd->rtqueues[pri];
1940 which = &rdd->rtqueuebits;
1943 q = &rdd->idqueues[pri];
1944 which = &rdd->idqueuebits;
1947 panic("remrunqueue: invalid rtprio type");
1952 * Place us on the selected queue. Determine if we should be
1953 * placed at the head of the queue or at the end.
1955 * We are placed at the tail if our round-robin count has expired,
1956 * or is about to expire and the system thinks its a good place to
1957 * round-robin, or there is already a next thread on the queue
1958 * (it might be trying to pick up where it left off and we don't
1959 * want to interfere).
1961 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0);
1962 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ);
1965 if (lp->lwp_rrcount >= usched_dfly_rrinterval ||
1966 (lp->lwp_rrcount >= usched_dfly_rrinterval / 2 &&
1967 (lp->lwp_thread->td_mpflags & TDF_MP_BATCH_DEMARC)) ||
1970 atomic_clear_int(&lp->lwp_thread->td_mpflags,
1971 TDF_MP_BATCH_DEMARC);
1972 lp->lwp_rrcount = 0;
1973 TAILQ_INSERT_TAIL(q, lp, lwp_procq);
1976 lp->lwp_rrcount = 0;
1977 TAILQ_INSERT_HEAD(q, lp, lwp_procq);
1983 * For SMP systems a user scheduler helper thread is created for each
1984 * cpu and is used to allow one cpu to wakeup another for the purposes of
1985 * scheduling userland threads from setrunqueue().
1987 * UP systems do not need the helper since there is only one cpu.
1989 * We can't use the idle thread for this because we might block.
1990 * Additionally, doing things this way allows us to HLT idle cpus
1994 dfly_helper_thread(void *dummy)
2004 cpuid = gd->gd_cpuid; /* doesn't change */
2005 mask = gd->gd_cpumask; /* doesn't change */
2006 dd = &dfly_pcpu[cpuid];
2009 * Since we only want to be woken up only when no user processes
2010 * are scheduled on a cpu, run at an ultra low priority.
2012 lwkt_setpri_self(TDPRI_USER_SCHEDULER);
2014 tsleep(&dd->helper_thread, 0, "schslp", 0);
2018 * We use the LWKT deschedule-interlock trick to avoid racing
2019 * dfly_rdyprocmask. This means we cannot block through to the
2020 * manual lwkt_switch() call we make below.
2023 tsleep_interlock(&dd->helper_thread, 0);
2025 spin_lock(&dd->spin);
2027 ATOMIC_CPUMASK_ORMASK(dfly_rdyprocmask, mask);
2028 clear_user_resched(); /* This satisfied the reschedule request */
2030 dd->rrcount = 0; /* Reset the round-robin counter */
2033 if (dd->runqcount || dd->uschedcp != NULL) {
2035 * Threads are available. A thread may or may not be
2036 * currently scheduled. Get the best thread already queued
2039 nlp = dfly_chooseproc_locked(dd, dd, dd->uschedcp, 0);
2041 ATOMIC_CPUMASK_ORMASK(dfly_curprocmask, mask);
2042 dd->upri = nlp->lwp_priority;
2045 dd->rrcount = 0; /* reset round robin */
2047 spin_unlock(&dd->spin);
2048 lwkt_acquire(nlp->lwp_thread);
2049 lwkt_schedule(nlp->lwp_thread);
2052 * This situation should not occur because we had
2053 * at least one thread available.
2055 spin_unlock(&dd->spin);
2057 } else if (usched_dfly_features & 0x01) {
2059 * This cpu is devoid of runnable threads, steal a thread
2060 * from another cpu. Since we're stealing, might as well
2061 * load balance at the same time.
2063 * We choose the highest-loaded thread from the worst queue.
2065 * NOTE! This function only returns a non-NULL rdd when
2066 * another cpu's queue is obviously overloaded. We
2067 * do not want to perform the type of rebalancing
2068 * the schedclock does here because it would result
2069 * in insane process pulling when 'steady' state is
2070 * partially unbalanced (e.g. 6 runnables and only
2073 rdd = dfly_choose_worst_queue(dd);
2074 if (rdd && spin_trylock(&rdd->spin)) {
2075 nlp = dfly_chooseproc_locked(rdd, dd, NULL, 1);
2076 spin_unlock(&rdd->spin);
2081 ATOMIC_CPUMASK_ORMASK(dfly_curprocmask, mask);
2082 dd->upri = nlp->lwp_priority;
2085 dd->rrcount = 0; /* reset round robin */
2087 spin_unlock(&dd->spin);
2088 lwkt_acquire(nlp->lwp_thread);
2089 lwkt_schedule(nlp->lwp_thread);
2092 * Leave the thread on our run queue. Another
2093 * scheduler will try to pull it later.
2095 spin_unlock(&dd->spin);
2099 * devoid of runnable threads and not allowed to steal
2102 spin_unlock(&dd->spin);
2106 * We're descheduled unless someone scheduled us. Switch away.
2107 * Exiting the critical section will cause splz() to be called
2108 * for us if interrupts and such are pending.
2111 tsleep(&dd->helper_thread, PINTERLOCKED, "schslp", 0);
2117 sysctl_usched_dfly_stick_to_level(SYSCTL_HANDLER_ARGS)
2121 new_val = usched_dfly_stick_to_level;
2123 error = sysctl_handle_int(oidp, &new_val, 0, req);
2124 if (error != 0 || req->newptr == NULL)
2126 if (new_val > cpu_topology_levels_number - 1 || new_val < 0)
2128 usched_dfly_stick_to_level = new_val;
2134 * Setup the queues and scheduler helpers (scheduler helpers are SMP only).
2135 * Note that curprocmask bit 0 has already been cleared by rqinit() and
2136 * we should not mess with it further.
2139 usched_dfly_cpu_init(void)
2143 int smt_not_supported = 0;
2144 int cache_coherent_not_supported = 0;
2147 kprintf("Start usched_dfly helpers on cpus:\n");
2149 sysctl_ctx_init(&usched_dfly_sysctl_ctx);
2150 usched_dfly_sysctl_tree =
2151 SYSCTL_ADD_NODE(&usched_dfly_sysctl_ctx,
2152 SYSCTL_STATIC_CHILDREN(_kern), OID_AUTO,
2153 "usched_dfly", CTLFLAG_RD, 0, "");
2155 for (i = 0; i < ncpus; ++i) {
2156 dfly_pcpu_t dd = &dfly_pcpu[i];
2159 CPUMASK_ASSBIT(mask, i);
2160 if (CPUMASK_TESTMASK(mask, smp_active_mask) == 0)
2163 spin_init(&dd->spin);
2164 dd->cpunode = get_cpu_node_by_cpuid(i);
2166 CPUMASK_ASSBIT(dd->cpumask, i);
2167 for (j = 0; j < NQS; j++) {
2168 TAILQ_INIT(&dd->queues[j]);
2169 TAILQ_INIT(&dd->rtqueues[j]);
2170 TAILQ_INIT(&dd->idqueues[j]);
2172 ATOMIC_CPUMASK_NANDBIT(dfly_curprocmask, 0);
2174 if (dd->cpunode == NULL) {
2175 smt_not_supported = 1;
2176 cache_coherent_not_supported = 1;
2178 kprintf (" cpu%d - WARNING: No CPU NODE "
2179 "found for cpu\n", i);
2181 switch (dd->cpunode->type) {
2184 kprintf (" cpu%d - HyperThreading "
2185 "available. Core siblings: ",
2189 smt_not_supported = 1;
2192 kprintf (" cpu%d - No HT available, "
2193 "multi-core/physical "
2194 "cpu. Physical siblings: ",
2198 smt_not_supported = 1;
2201 kprintf (" cpu%d - No HT available, "
2202 "single-core/physical cpu. "
2203 "Package siblings: ",
2207 /* Let's go for safe defaults here */
2208 smt_not_supported = 1;
2209 cache_coherent_not_supported = 1;
2211 kprintf (" cpu%d - Unknown cpunode->"
2212 "type=%u. siblings: ",
2214 (u_int)dd->cpunode->type);
2219 if (dd->cpunode->parent_node != NULL) {
2220 kprint_cpuset(&dd->cpunode->
2221 parent_node->members);
2224 kprintf(" no siblings\n");
2229 lwkt_create(dfly_helper_thread, NULL, NULL, &dd->helper_thread,
2230 0, i, "usched %d", i);
2233 * Allow user scheduling on the target cpu. cpu #0 has already
2234 * been enabled in rqinit().
2237 ATOMIC_CPUMASK_NANDMASK(dfly_curprocmask, mask);
2238 ATOMIC_CPUMASK_ORMASK(dfly_rdyprocmask, mask);
2239 dd->upri = PRIBASE_NULL;
2243 /* usched_dfly sysctl configurable parameters */
2245 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2246 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2247 OID_AUTO, "rrinterval", CTLFLAG_RW,
2248 &usched_dfly_rrinterval, 0, "");
2249 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2250 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2251 OID_AUTO, "decay", CTLFLAG_RW,
2252 &usched_dfly_decay, 0, "Extra decay when not running");
2254 /* Add enable/disable option for SMT scheduling if supported */
2255 if (smt_not_supported) {
2256 usched_dfly_smt = 0;
2257 SYSCTL_ADD_STRING(&usched_dfly_sysctl_ctx,
2258 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2259 OID_AUTO, "smt", CTLFLAG_RD,
2260 "NOT SUPPORTED", 0, "SMT NOT SUPPORTED");
2262 usched_dfly_smt = 1;
2263 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2264 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2265 OID_AUTO, "smt", CTLFLAG_RW,
2266 &usched_dfly_smt, 0, "Enable SMT scheduling");
2270 * Add enable/disable option for cache coherent scheduling
2273 if (cache_coherent_not_supported) {
2274 usched_dfly_cache_coherent = 0;
2275 SYSCTL_ADD_STRING(&usched_dfly_sysctl_ctx,
2276 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2277 OID_AUTO, "cache_coherent", CTLFLAG_RD,
2279 "Cache coherence NOT SUPPORTED");
2281 usched_dfly_cache_coherent = 1;
2282 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2283 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2284 OID_AUTO, "cache_coherent", CTLFLAG_RW,
2285 &usched_dfly_cache_coherent, 0,
2286 "Enable/Disable cache coherent scheduling");
2288 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2289 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2290 OID_AUTO, "weight1", CTLFLAG_RW,
2291 &usched_dfly_weight1, 200,
2292 "Weight selection for current cpu");
2294 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2295 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2296 OID_AUTO, "weight2", CTLFLAG_RW,
2297 &usched_dfly_weight2, 180,
2298 "Weight selection for wakefrom cpu");
2300 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2301 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2302 OID_AUTO, "weight3", CTLFLAG_RW,
2303 &usched_dfly_weight3, 40,
2304 "Weight selection for num threads on queue");
2306 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2307 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2308 OID_AUTO, "weight4", CTLFLAG_RW,
2309 &usched_dfly_weight4, 160,
2310 "Availability of other idle cpus");
2312 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2313 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2314 OID_AUTO, "fast_resched", CTLFLAG_RW,
2315 &usched_dfly_fast_resched, 0,
2316 "Availability of other idle cpus");
2318 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2319 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2320 OID_AUTO, "features", CTLFLAG_RW,
2321 &usched_dfly_features, 0x8F,
2322 "Allow pulls into empty queues");
2324 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
2325 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2326 OID_AUTO, "swmask", CTLFLAG_RW,
2327 &usched_dfly_swmask, ~PPQMASK,
2328 "Queue mask to force thread switch");
2331 SYSCTL_ADD_PROC(&usched_dfly_sysctl_ctx,
2332 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
2333 OID_AUTO, "stick_to_level",
2334 CTLTYPE_INT | CTLFLAG_RW,
2335 NULL, sizeof usched_dfly_stick_to_level,
2336 sysctl_usched_dfly_stick_to_level, "I",
2337 "Stick a process to this level. See sysctl"
2338 "paremter hw.cpu_topology.level_description");
2342 SYSINIT(uschedtd, SI_BOOT2_USCHED, SI_ORDER_SECOND,
2343 usched_dfly_cpu_init, NULL)