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
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
36 #include <sys/queue.h>
38 #include <sys/rtprio.h>
40 #include <sys/sysctl.h>
41 #include <sys/resourcevar.h>
42 #include <sys/spinlock.h>
43 #include <sys/cpu_topology.h>
44 #include <sys/thread2.h>
45 #include <sys/spinlock2.h>
46 #include <sys/mplock2.h>
50 #include <machine/cpu.h>
51 #include <machine/smp.h>
54 * Priorities. Note that with 32 run queues per scheduler each queue
55 * represents four priority levels.
59 #define PRIMASK (MAXPRI - 1)
60 #define PRIBASE_REALTIME 0
61 #define PRIBASE_NORMAL MAXPRI
62 #define PRIBASE_IDLE (MAXPRI * 2)
63 #define PRIBASE_THREAD (MAXPRI * 3)
64 #define PRIBASE_NULL (MAXPRI * 4)
66 #define NQS 32 /* 32 run queues. */
67 #define PPQ (MAXPRI / NQS) /* priorities per queue */
68 #define PPQMASK (PPQ - 1)
71 * NICEPPQ - number of nice units per priority queue
73 * ESTCPUPPQ - number of estcpu units per priority queue
74 * ESTCPUMAX - number of estcpu units
78 #define ESTCPUMAX (ESTCPUPPQ * NQS)
79 #define BATCHMAX (ESTCPUFREQ * 30)
80 #define PRIO_RANGE (PRIO_MAX - PRIO_MIN + 1)
82 #define ESTCPULIM(v) min((v), ESTCPUMAX)
86 #define lwp_priority lwp_usdata.bsd4.priority
87 #define lwp_rqindex lwp_usdata.bsd4.rqindex
88 #define lwp_estcpu lwp_usdata.bsd4.estcpu
89 #define lwp_batch lwp_usdata.bsd4.batch
90 #define lwp_rqtype lwp_usdata.bsd4.rqtype
92 static void bsd4_acquire_curproc(struct lwp *lp);
93 static void bsd4_release_curproc(struct lwp *lp);
94 static void bsd4_select_curproc(globaldata_t gd);
95 static void bsd4_setrunqueue(struct lwp *lp);
96 static void bsd4_schedulerclock(struct lwp *lp, sysclock_t period,
98 static void bsd4_recalculate_estcpu(struct lwp *lp);
99 static void bsd4_resetpriority(struct lwp *lp);
100 static void bsd4_forking(struct lwp *plp, struct lwp *lp);
101 static void bsd4_exiting(struct lwp *lp, struct proc *);
102 static void bsd4_uload_update(struct lwp *lp);
103 static void bsd4_yield(struct lwp *lp);
106 static void bsd4_need_user_resched_remote(void *dummy);
107 static int bsd4_batchy_looser_pri_test(struct lwp* lp);
108 static struct lwp *bsd4_chooseproc_locked_cache_coherent(struct lwp *chklp);
109 static void bsd4_kick_helper(struct lwp *lp);
111 static struct lwp *bsd4_chooseproc_locked(struct lwp *chklp);
112 static void bsd4_remrunqueue_locked(struct lwp *lp);
113 static void bsd4_setrunqueue_locked(struct lwp *lp);
115 struct usched usched_bsd4 = {
117 "bsd4", "Original DragonFly Scheduler",
118 NULL, /* default registration */
119 NULL, /* default deregistration */
120 bsd4_acquire_curproc,
121 bsd4_release_curproc,
124 bsd4_recalculate_estcpu,
129 NULL, /* setcpumask not supported */
133 struct usched_bsd4_pcpu {
134 struct thread helper_thread;
137 struct lwp *uschedcp;
138 struct lwp *old_uschedcp;
144 typedef struct usched_bsd4_pcpu *bsd4_pcpu_t;
147 * We have NQS (32) run queues per scheduling class. For the normal
148 * class, there are 128 priorities scaled onto these 32 queues. New
149 * processes are added to the last entry in each queue, and processes
150 * are selected for running by taking them from the head and maintaining
151 * a simple FIFO arrangement. Realtime and Idle priority processes have
152 * and explicit 0-31 priority which maps directly onto their class queue
153 * index. When a queue has something in it, the corresponding bit is
154 * set in the queuebits variable, allowing a single read to determine
155 * the state of all 32 queues and then a ffs() to find the first busy
158 static struct rq bsd4_queues[NQS];
159 static struct rq bsd4_rtqueues[NQS];
160 static struct rq bsd4_idqueues[NQS];
161 static u_int32_t bsd4_queuebits;
162 static u_int32_t bsd4_rtqueuebits;
163 static u_int32_t bsd4_idqueuebits;
164 static cpumask_t bsd4_curprocmask = -1; /* currently running a user process */
165 static cpumask_t bsd4_rdyprocmask; /* ready to accept a user process */
166 static int bsd4_runqcount;
168 static volatile int bsd4_scancpu;
170 static struct spinlock bsd4_spin;
171 static struct usched_bsd4_pcpu bsd4_pcpu[MAXCPU];
172 static struct sysctl_ctx_list usched_bsd4_sysctl_ctx;
173 static struct sysctl_oid *usched_bsd4_sysctl_tree;
175 /* Debug info exposed through debug.* sysctl */
177 SYSCTL_INT(_debug, OID_AUTO, bsd4_runqcount, CTLFLAG_RD,
179 "Number of run queues");
181 static int usched_bsd4_debug = -1;
182 SYSCTL_INT(_debug, OID_AUTO, bsd4_scdebug, CTLFLAG_RW,
183 &usched_bsd4_debug, 0,
184 "Print debug information for this pid");
186 static int usched_bsd4_pid_debug = -1;
187 SYSCTL_INT(_debug, OID_AUTO, bsd4_pid_debug, CTLFLAG_RW,
188 &usched_bsd4_pid_debug, 0,
189 "Print KTR debug information for this pid");
191 /* Tunning usched_bsd4 - configurable through kern.usched_bsd4.* */
193 static int usched_bsd4_smt = 0;
194 static int usched_bsd4_cache_coherent = 0;
195 static int usched_bsd4_upri_affinity = 16; /* 32 queues - half-way */
196 static int usched_bsd4_queue_checks = 5;
197 static int usched_bsd4_stick_to_level = 0;
198 static long usched_bsd4_kicks;
200 static int usched_bsd4_rrinterval = (ESTCPUFREQ + 9) / 10;
201 static int usched_bsd4_decay = 8;
202 static int usched_bsd4_batch_time = 10;
204 /* KTR debug printings */
206 KTR_INFO_MASTER_EXTERN(usched);
208 #if !defined(KTR_USCHED_BSD4)
209 #define KTR_USCHED_BSD4 KTR_ALL
212 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_acquire_curproc_urw, 0,
213 "USCHED_BSD4(bsd4_acquire_curproc in user_reseched_wanted "
214 "after release: pid %d, cpuid %d, curr_cpuid %d)",
215 pid_t pid, int cpuid, int curr);
216 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_acquire_curproc_before_loop, 0,
217 "USCHED_BSD4(bsd4_acquire_curproc before loop: pid %d, cpuid %d, "
219 pid_t pid, int cpuid, int curr);
220 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_acquire_curproc_not, 0,
221 "USCHED_BSD4(bsd4_acquire_curproc couldn't acquire after "
222 "bsd4_setrunqueue: pid %d, cpuid %d, curr_lp pid %d, curr_cpuid %d)",
223 pid_t pid, int cpuid, pid_t curr_pid, int curr_cpuid);
224 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_acquire_curproc_switch, 0,
225 "USCHED_BSD4(bsd4_acquire_curproc after lwkt_switch: pid %d, "
226 "cpuid %d, curr_cpuid %d)",
227 pid_t pid, int cpuid, int curr);
229 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_release_curproc, 0,
230 "USCHED_BSD4(bsd4_release_curproc before select: pid %d, "
231 "cpuid %d, curr_cpuid %d)",
232 pid_t pid, int cpuid, int curr);
234 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_select_curproc, 0,
235 "USCHED_BSD4(bsd4_release_curproc before select: pid %d, "
236 "cpuid %d, old_pid %d, old_cpuid %d, curr_cpuid %d)",
237 pid_t pid, int cpuid, pid_t old_pid, int old_cpuid, int curr);
240 KTR_INFO(KTR_USCHED_BSD4, usched, batchy_test_false, 0,
241 "USCHED_BSD4(batchy_looser_pri_test false: pid %d, "
242 "cpuid %d, verify_mask %lu)",
243 pid_t pid, int cpuid, cpumask_t mask);
244 KTR_INFO(KTR_USCHED_BSD4, usched, batchy_test_true, 0,
245 "USCHED_BSD4(batchy_looser_pri_test true: pid %d, "
246 "cpuid %d, verify_mask %lu)",
247 pid_t pid, int cpuid, cpumask_t mask);
249 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_setrunqueue_fc_smt, 0,
250 "USCHED_BSD4(bsd4_setrunqueue free cpus smt: pid %d, cpuid %d, "
251 "mask %lu, curr_cpuid %d)",
252 pid_t pid, int cpuid, cpumask_t mask, int curr);
253 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_setrunqueue_fc_non_smt, 0,
254 "USCHED_BSD4(bsd4_setrunqueue free cpus check non_smt: pid %d, "
255 "cpuid %d, mask %lu, curr_cpuid %d)",
256 pid_t pid, int cpuid, cpumask_t mask, int curr);
257 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_setrunqueue_rc, 0,
258 "USCHED_BSD4(bsd4_setrunqueue running cpus check: pid %d, "
259 "cpuid %d, mask %lu, curr_cpuid %d)",
260 pid_t pid, int cpuid, cpumask_t mask, int curr);
261 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_setrunqueue_found, 0,
262 "USCHED_BSD4(bsd4_setrunqueue found cpu: pid %d, cpuid %d, "
263 "mask %lu, found_cpuid %d, curr_cpuid %d)",
264 pid_t pid, int cpuid, cpumask_t mask, int found_cpuid, int curr);
265 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_setrunqueue_not_found, 0,
266 "USCHED_BSD4(bsd4_setrunqueue not found cpu: pid %d, cpuid %d, "
267 "try_cpuid %d, curr_cpuid %d)",
268 pid_t pid, int cpuid, int try_cpuid, int curr);
269 KTR_INFO(KTR_USCHED_BSD4, usched, bsd4_setrunqueue_found_best_cpuid, 0,
270 "USCHED_BSD4(bsd4_setrunqueue found cpu: pid %d, cpuid %d, "
271 "mask %lu, found_cpuid %d, curr_cpuid %d)",
272 pid_t pid, int cpuid, cpumask_t mask, int found_cpuid, int curr);
275 KTR_INFO(KTR_USCHED_BSD4, usched, chooseproc, 0,
276 "USCHED_BSD4(chooseproc: pid %d, old_cpuid %d, curr_cpuid %d)",
277 pid_t pid, int old_cpuid, int curr);
279 KTR_INFO(KTR_USCHED_BSD4, usched, chooseproc_cc, 0,
280 "USCHED_BSD4(chooseproc_cc: pid %d, old_cpuid %d, curr_cpuid %d)",
281 pid_t pid, int old_cpuid, int curr);
282 KTR_INFO(KTR_USCHED_BSD4, usched, chooseproc_cc_not_good, 0,
283 "USCHED_BSD4(chooseproc_cc not good: pid %d, old_cpumask %lu, "
284 "sibling_mask %lu, curr_cpumask %lu)",
285 pid_t pid, cpumask_t old_cpumask, cpumask_t sibling_mask, cpumask_t curr);
286 KTR_INFO(KTR_USCHED_BSD4, usched, chooseproc_cc_elected, 0,
287 "USCHED_BSD4(chooseproc_cc elected: pid %d, old_cpumask %lu, "
288 "sibling_mask %lu, curr_cpumask: %lu)",
289 pid_t pid, cpumask_t old_cpumask, cpumask_t sibling_mask, cpumask_t curr);
291 KTR_INFO(KTR_USCHED_BSD4, usched, sched_thread_no_process, 0,
292 "USCHED_BSD4(sched_thread %d no process scheduled: pid %d, old_cpuid %d)",
293 int id, pid_t pid, int cpuid);
294 KTR_INFO(KTR_USCHED_BSD4, usched, sched_thread_process, 0,
295 "USCHED_BSD4(sched_thread %d process scheduled: pid %d, old_cpuid %d)",
296 int id, pid_t pid, int cpuid);
297 KTR_INFO(KTR_USCHED_BSD4, usched, sched_thread_no_process_found, 0,
298 "USCHED_BSD4(sched_thread %d no process found; tmpmask %lu)",
299 int id, cpumask_t tmpmask);
303 * Initialize the run queues at boot time.
306 bsd4_rqinit(void *dummy)
310 spin_init(&bsd4_spin);
311 for (i = 0; i < NQS; i++) {
312 TAILQ_INIT(&bsd4_queues[i]);
313 TAILQ_INIT(&bsd4_rtqueues[i]);
314 TAILQ_INIT(&bsd4_idqueues[i]);
316 atomic_clear_cpumask(&bsd4_curprocmask, 1);
318 SYSINIT(runqueue, SI_BOOT2_USCHED, SI_ORDER_FIRST, bsd4_rqinit, NULL)
321 * BSD4_ACQUIRE_CURPROC
323 * This function is called when the kernel intends to return to userland.
324 * It is responsible for making the thread the current designated userland
325 * thread for this cpu, blocking if necessary.
327 * The kernel will not depress our LWKT priority until after we return,
328 * in case we have to shove over to another cpu.
330 * We must determine our thread's disposition before we switch away. This
331 * is very sensitive code.
333 * WARNING! THIS FUNCTION IS ALLOWED TO CAUSE THE CURRENT THREAD TO MIGRATE
334 * TO ANOTHER CPU! Because most of the kernel assumes that no migration will
335 * occur, this function is called only under very controlled circumstances.
340 bsd4_acquire_curproc(struct lwp *lp)
350 * Make sure we aren't sitting on a tsleep queue.
353 crit_enter_quick(td);
354 if (td->td_flags & TDF_TSLEEPQ)
356 bsd4_recalculate_estcpu(lp);
359 * If a reschedule was requested give another thread the
362 if (user_resched_wanted()) {
363 clear_user_resched();
364 bsd4_release_curproc(lp);
366 KTR_COND_LOG(usched_bsd4_acquire_curproc_urw,
367 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
369 lp->lwp_thread->td_gd->gd_cpuid,
374 * Loop until we are the current user thread
377 dd = &bsd4_pcpu[gd->gd_cpuid];
379 KTR_COND_LOG(usched_bsd4_acquire_curproc_before_loop,
380 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
382 lp->lwp_thread->td_gd->gd_cpuid,
387 * Process any pending events and higher priority threads.
392 * Become the currently scheduled user thread for this cpu
393 * if we can do so trivially.
395 * We can steal another thread's current thread designation
396 * on this cpu since if we are running that other thread
397 * must not be, so we can safely deschedule it.
399 if (dd->uschedcp == lp) {
401 * We are already the current lwp (hot path).
403 dd->upri = lp->lwp_priority;
404 } else if (dd->uschedcp == NULL) {
406 * We can trivially become the current lwp.
408 atomic_set_cpumask(&bsd4_curprocmask, gd->gd_cpumask);
410 dd->upri = lp->lwp_priority;
411 } else if (dd->upri > lp->lwp_priority) {
413 * We can steal the current cpu's lwp designation
414 * away simply by replacing it. The other thread
415 * will stall when it tries to return to userland.
418 dd->upri = lp->lwp_priority;
420 lwkt_deschedule(olp->lwp_thread);
421 bsd4_setrunqueue(olp);
425 * We cannot become the current lwp, place the lp
426 * on the bsd4 run-queue and deschedule ourselves.
428 * When we are reactivated we will have another
431 lwkt_deschedule(lp->lwp_thread);
433 bsd4_setrunqueue(lp);
435 KTR_COND_LOG(usched_bsd4_acquire_curproc_not,
436 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
438 lp->lwp_thread->td_gd->gd_cpuid,
439 dd->uschedcp->lwp_proc->p_pid,
446 * Reload after a switch or setrunqueue/switch possibly
447 * moved us to another cpu.
450 dd = &bsd4_pcpu[gd->gd_cpuid];
452 KTR_COND_LOG(usched_bsd4_acquire_curproc_switch,
453 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
455 lp->lwp_thread->td_gd->gd_cpuid,
458 } while (dd->uschedcp != lp);
461 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0);
465 * BSD4_RELEASE_CURPROC
467 * This routine detaches the current thread from the userland scheduler,
468 * usually because the thread needs to run or block in the kernel (at
469 * kernel priority) for a while.
471 * This routine is also responsible for selecting a new thread to
472 * make the current thread.
474 * NOTE: This implementation differs from the dummy example in that
475 * bsd4_select_curproc() is able to select the current process, whereas
476 * dummy_select_curproc() is not able to select the current process.
477 * This means we have to NULL out uschedcp.
479 * Additionally, note that we may already be on a run queue if releasing
480 * via the lwkt_switch() in bsd4_setrunqueue().
486 bsd4_release_curproc(struct lwp *lp)
488 globaldata_t gd = mycpu;
489 bsd4_pcpu_t dd = &bsd4_pcpu[gd->gd_cpuid];
491 if (dd->uschedcp == lp) {
493 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0);
495 KTR_COND_LOG(usched_bsd4_release_curproc,
496 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
498 lp->lwp_thread->td_gd->gd_cpuid,
501 dd->uschedcp = NULL; /* don't let lp be selected */
502 dd->upri = PRIBASE_NULL;
503 atomic_clear_cpumask(&bsd4_curprocmask, gd->gd_cpumask);
504 dd->old_uschedcp = lp; /* used only for KTR debug prints */
505 bsd4_select_curproc(gd);
511 * BSD4_SELECT_CURPROC
513 * Select a new current process for this cpu and clear any pending user
514 * reschedule request. The cpu currently has no current process.
516 * This routine is also responsible for equal-priority round-robining,
517 * typically triggered from bsd4_schedulerclock(). In our dummy example
518 * all the 'user' threads are LWKT scheduled all at once and we just
519 * call lwkt_switch().
521 * The calling process is not on the queue and cannot be selected.
527 bsd4_select_curproc(globaldata_t gd)
529 bsd4_pcpu_t dd = &bsd4_pcpu[gd->gd_cpuid];
531 int cpuid = gd->gd_cpuid;
535 spin_lock(&bsd4_spin);
537 if(usched_bsd4_cache_coherent)
538 nlp = bsd4_chooseproc_locked_cache_coherent(dd->uschedcp);
541 nlp = bsd4_chooseproc_locked(dd->uschedcp);
545 KTR_COND_LOG(usched_bsd4_select_curproc,
546 nlp->lwp_proc->p_pid == usched_bsd4_pid_debug,
547 nlp->lwp_proc->p_pid,
548 nlp->lwp_thread->td_gd->gd_cpuid,
549 dd->old_uschedcp->lwp_proc->p_pid,
550 dd->old_uschedcp->lwp_thread->td_gd->gd_cpuid,
553 atomic_set_cpumask(&bsd4_curprocmask, CPUMASK(cpuid));
554 dd->upri = nlp->lwp_priority;
556 dd->rrcount = 0; /* reset round robin */
557 spin_unlock(&bsd4_spin);
559 lwkt_acquire(nlp->lwp_thread);
561 lwkt_schedule(nlp->lwp_thread);
563 spin_unlock(&bsd4_spin);
567 } else if (bsd4_runqcount && (bsd4_rdyprocmask & CPUMASK(cpuid))) {
568 atomic_clear_cpumask(&bsd4_rdyprocmask, CPUMASK(cpuid));
569 spin_unlock(&bsd4_spin);
570 lwkt_schedule(&dd->helper_thread);
572 spin_unlock(&bsd4_spin);
580 * batchy_looser_pri_test() - determine if a process is batchy or not
581 * relative to the other processes running in the system
584 bsd4_batchy_looser_pri_test(struct lwp* lp)
587 bsd4_pcpu_t other_dd;
590 /* Current running processes */
591 mask = bsd4_curprocmask & smp_active_mask
592 & usched_global_cpumask;
595 cpu = BSFCPUMASK(mask);
596 other_dd = &bsd4_pcpu[cpu];
597 if (other_dd->upri - lp->lwp_priority > usched_bsd4_upri_affinity * PPQ) {
599 KTR_COND_LOG(usched_batchy_test_false,
600 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
602 lp->lwp_thread->td_gd->gd_cpuid,
603 (unsigned long)mask);
607 mask &= ~CPUMASK(cpu);
610 KTR_COND_LOG(usched_batchy_test_true,
611 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
613 lp->lwp_thread->td_gd->gd_cpuid,
614 (unsigned long)mask);
624 * Place the specified lwp on the user scheduler's run queue. This routine
625 * must be called with the thread descheduled. The lwp must be runnable.
627 * The thread may be the current thread as a special case.
632 bsd4_setrunqueue(struct lwp *lp)
643 * First validate the process state relative to the current cpu.
644 * We don't need the spinlock for this, just a critical section.
645 * We are in control of the process.
648 KASSERT(lp->lwp_stat == LSRUN, ("setrunqueue: lwp not LSRUN"));
649 KASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0,
650 ("lwp %d/%d already on runq! flag %08x/%08x", lp->lwp_proc->p_pid,
651 lp->lwp_tid, lp->lwp_proc->p_flags, lp->lwp_flags));
652 KKASSERT((lp->lwp_thread->td_flags & TDF_RUNQ) == 0);
655 * Note: gd and dd are relative to the target thread's last cpu,
656 * NOT our current cpu.
658 gd = lp->lwp_thread->td_gd;
659 dd = &bsd4_pcpu[gd->gd_cpuid];
662 * This process is not supposed to be scheduled anywhere or assigned
663 * as the current process anywhere. Assert the condition.
665 KKASSERT(dd->uschedcp != lp);
669 * If we are not SMP we do not have a scheduler helper to kick
670 * and must directly activate the process if none are scheduled.
672 * This is really only an issue when bootstrapping init since
673 * the caller in all other cases will be a user process, and
674 * even if released (dd->uschedcp == NULL), that process will
675 * kickstart the scheduler when it returns to user mode from
678 if (dd->uschedcp == NULL) {
679 atomic_set_cpumask(&bsd4_curprocmask, gd->gd_cpumask);
681 dd->upri = lp->lwp_priority;
682 lwkt_schedule(lp->lwp_thread);
690 * XXX fixme. Could be part of a remrunqueue/setrunqueue
691 * operation when the priority is recalculated, so TDF_MIGRATING
692 * may already be set.
694 if ((lp->lwp_thread->td_flags & TDF_MIGRATING) == 0)
695 lwkt_giveaway(lp->lwp_thread);
699 * We lose control of lp the moment we release the spinlock after
700 * having placed lp on the queue. i.e. another cpu could pick it
701 * up and it could exit, or its priority could be further adjusted,
702 * or something like that.
704 spin_lock(&bsd4_spin);
705 bsd4_setrunqueue_locked(lp);
706 lp->lwp_rebal_ticks = sched_ticks;
710 * Kick the scheduler helper on one of the other cpu's
711 * and request a reschedule if appropriate.
713 * NOTE: We check all cpus whos rdyprocmask is set. First we
714 * look for cpus without designated lps, then we look for
715 * cpus with designated lps with a worse priority than our
720 if (usched_bsd4_smt) {
723 * SMT heuristic - Try to schedule on a free physical core.
724 * If no physical core found than choose the one that has
725 * an interactive thread.
729 int min_prio = MAXPRI * MAXPRI;
732 cpuid = (bsd4_scancpu & 0xFFFF) % ncpus;
733 mask = ~bsd4_curprocmask & bsd4_rdyprocmask & lp->lwp_cpumask &
734 smp_active_mask & usched_global_cpumask;
736 KTR_COND_LOG(usched_bsd4_setrunqueue_fc_smt,
737 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
739 lp->lwp_thread->td_gd->gd_cpuid,
744 tmpmask = ~(CPUMASK(cpuid) - 1);
746 cpuid = BSFCPUMASK(mask & tmpmask);
748 cpuid = BSFCPUMASK(mask);
749 gd = globaldata_find(cpuid);
750 dd = &bsd4_pcpu[cpuid];
752 if ((dd->upri & ~PPQMASK) >= (lp->lwp_priority & ~PPQMASK)) {
753 if (dd->cpunode->parent_node->members & ~dd->cpunode->members & mask) {
755 KTR_COND_LOG(usched_bsd4_setrunqueue_found,
756 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
758 lp->lwp_thread->td_gd->gd_cpuid,
765 sibling = BSFCPUMASK(dd->cpunode->parent_node->members &
766 ~dd->cpunode->members);
767 if (min_prio > bsd4_pcpu[sibling].upri) {
768 min_prio = bsd4_pcpu[sibling].upri;
773 mask &= ~CPUMASK(cpuid);
776 if (best_cpuid != -1) {
778 gd = globaldata_find(cpuid);
779 dd = &bsd4_pcpu[cpuid];
781 KTR_COND_LOG(usched_bsd4_setrunqueue_found_best_cpuid,
782 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
784 lp->lwp_thread->td_gd->gd_cpuid,
792 /* Fallback to the original heuristic */
793 cpuid = (bsd4_scancpu & 0xFFFF) % ncpus;
794 mask = ~bsd4_curprocmask & bsd4_rdyprocmask & lp->lwp_cpumask &
795 smp_active_mask & usched_global_cpumask;
797 KTR_COND_LOG(usched_bsd4_setrunqueue_fc_non_smt,
798 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
800 lp->lwp_thread->td_gd->gd_cpuid,
805 tmpmask = ~(CPUMASK(cpuid) - 1);
807 cpuid = BSFCPUMASK(mask & tmpmask);
809 cpuid = BSFCPUMASK(mask);
810 gd = globaldata_find(cpuid);
811 dd = &bsd4_pcpu[cpuid];
813 if ((dd->upri & ~PPQMASK) >= (lp->lwp_priority & ~PPQMASK)) {
815 KTR_COND_LOG(usched_bsd4_setrunqueue_found,
816 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
818 lp->lwp_thread->td_gd->gd_cpuid,
825 mask &= ~CPUMASK(cpuid);
830 * Then cpus which might have a currently running lp
832 mask = bsd4_curprocmask & bsd4_rdyprocmask &
833 lp->lwp_cpumask & smp_active_mask & usched_global_cpumask;
835 KTR_COND_LOG(usched_bsd4_setrunqueue_rc,
836 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
838 lp->lwp_thread->td_gd->gd_cpuid,
843 tmpmask = ~(CPUMASK(cpuid) - 1);
845 cpuid = BSFCPUMASK(mask & tmpmask);
847 cpuid = BSFCPUMASK(mask);
848 gd = globaldata_find(cpuid);
849 dd = &bsd4_pcpu[cpuid];
851 if ((dd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK)) {
853 KTR_COND_LOG(usched_bsd4_setrunqueue_found,
854 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
856 lp->lwp_thread->td_gd->gd_cpuid,
863 mask &= ~CPUMASK(cpuid);
867 * If we cannot find a suitable cpu we reload from bsd4_scancpu
868 * and round-robin. Other cpus will pickup as they release their
869 * current lwps or become ready.
871 * Avoid a degenerate system lockup case if usched_global_cpumask
872 * is set to 0 or otherwise does not cover lwp_cpumask.
874 * We only kick the target helper thread in this case, we do not
875 * set the user resched flag because
877 cpuid = (bsd4_scancpu & 0xFFFF) % ncpus;
878 if ((CPUMASK(cpuid) & usched_global_cpumask) == 0) {
881 gd = globaldata_find(cpuid);
882 dd = &bsd4_pcpu[cpuid];
884 KTR_COND_LOG(usched_bsd4_setrunqueue_not_found,
885 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
887 lp->lwp_thread->td_gd->gd_cpuid,
893 spin_unlock(&bsd4_spin);
894 if ((dd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK)) {
895 if (dd->uschedcp == NULL) {
896 wakeup_mycpu(&dd->helper_thread);
902 atomic_clear_cpumask(&bsd4_rdyprocmask, CPUMASK(cpuid));
903 spin_unlock(&bsd4_spin);
904 if ((dd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK))
905 lwkt_send_ipiq(gd, bsd4_need_user_resched_remote, NULL);
907 wakeup(&dd->helper_thread);
911 * Request a reschedule if appropriate.
913 spin_unlock(&bsd4_spin);
914 if ((dd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK)) {
922 * This routine is called from a systimer IPI. It MUST be MP-safe and
923 * the BGL IS NOT HELD ON ENTRY. This routine is called at ESTCPUFREQ on
926 * This routine is called on every sched tick. If the currently running
927 * thread belongs to this scheduler it will be called with a non-NULL lp,
928 * otherwise it will be called with a NULL lp.
934 bsd4_schedulerclock(struct lwp *lp, sysclock_t period, sysclock_t cpstamp)
936 globaldata_t gd = mycpu;
937 bsd4_pcpu_t dd = &bsd4_pcpu[gd->gd_cpuid];
940 * No impl if no lp running.
946 * Do we need to round-robin? We round-robin 10 times a second.
947 * This should only occur for cpu-bound batch processes.
949 if (++dd->rrcount >= usched_bsd4_rrinterval) {
955 * Adjust estcpu upward using a real time equivalent calculation.
957 lp->lwp_estcpu = ESTCPULIM(lp->lwp_estcpu + ESTCPUMAX / ESTCPUFREQ + 1);
960 * Spinlocks also hold a critical section so there should not be
963 KKASSERT(gd->gd_spinlocks == 0);
965 bsd4_resetpriority(lp);
969 * Called from acquire and from kern_synch's one-second timer (one of the
970 * callout helper threads) with a critical section held.
972 * Decay p_estcpu based on the number of ticks we haven't been running
973 * and our p_nice. As the load increases each process observes a larger
974 * number of idle ticks (because other processes are running in them).
975 * This observation leads to a larger correction which tends to make the
976 * system more 'batchy'.
978 * Note that no recalculation occurs for a process which sleeps and wakes
979 * up in the same tick. That is, a system doing thousands of context
980 * switches per second will still only do serious estcpu calculations
981 * ESTCPUFREQ times per second.
987 bsd4_recalculate_estcpu(struct lwp *lp)
989 globaldata_t gd = mycpu;
996 * We have to subtract periodic to get the last schedclock
997 * timeout time, otherwise we would get the upcoming timeout.
998 * Keep in mind that a process can migrate between cpus and
999 * while the scheduler clock should be very close, boundary
1000 * conditions could lead to a small negative delta.
1002 cpbase = gd->gd_schedclock.time - gd->gd_schedclock.periodic;
1004 if (lp->lwp_slptime > 1) {
1006 * Too much time has passed, do a coarse correction.
1008 lp->lwp_estcpu = lp->lwp_estcpu >> 1;
1009 bsd4_resetpriority(lp);
1010 lp->lwp_cpbase = cpbase;
1011 lp->lwp_cpticks = 0;
1012 lp->lwp_batch -= ESTCPUFREQ;
1013 if (lp->lwp_batch < 0)
1015 } else if (lp->lwp_cpbase != cpbase) {
1017 * Adjust estcpu if we are in a different tick. Don't waste
1018 * time if we are in the same tick.
1020 * First calculate the number of ticks in the measurement
1021 * interval. The ttlticks calculation can wind up 0 due to
1022 * a bug in the handling of lwp_slptime (as yet not found),
1023 * so make sure we do not get a divide by 0 panic.
1025 ttlticks = (cpbase - lp->lwp_cpbase) /
1026 gd->gd_schedclock.periodic;
1029 lp->lwp_cpbase = cpbase;
1033 updatepcpu(lp, lp->lwp_cpticks, ttlticks);
1036 * Calculate the percentage of one cpu used factoring in ncpus
1037 * and the load and adjust estcpu. Handle degenerate cases
1038 * by adding 1 to bsd4_runqcount.
1040 * estcpu is scaled by ESTCPUMAX.
1042 * bsd4_runqcount is the excess number of user processes
1043 * that cannot be immediately scheduled to cpus. We want
1044 * to count these as running to avoid range compression
1045 * in the base calculation (which is the actual percentage
1048 estcpu = (lp->lwp_cpticks * ESTCPUMAX) *
1049 (bsd4_runqcount + ncpus) / (ncpus * ttlticks);
1052 * If estcpu is > 50% we become more batch-like
1053 * If estcpu is <= 50% we become less batch-like
1055 * It takes 30 cpu seconds to traverse the entire range.
1057 if (estcpu > ESTCPUMAX / 2) {
1058 lp->lwp_batch += ttlticks;
1059 if (lp->lwp_batch > BATCHMAX)
1060 lp->lwp_batch = BATCHMAX;
1062 lp->lwp_batch -= ttlticks;
1063 if (lp->lwp_batch < 0)
1067 if (usched_bsd4_debug == lp->lwp_proc->p_pid) {
1068 kprintf("pid %d lwp %p estcpu %3d %3d bat %d cp %d/%d",
1069 lp->lwp_proc->p_pid, lp,
1070 estcpu, lp->lwp_estcpu,
1072 lp->lwp_cpticks, ttlticks);
1076 * Adjust lp->lwp_esetcpu. The decay factor determines how
1077 * quickly lwp_estcpu collapses to its realtime calculation.
1078 * A slower collapse gives us a more accurate number but
1079 * can cause a cpu hog to eat too much cpu before the
1080 * scheduler decides to downgrade it.
1082 * NOTE: p_nice is accounted for in bsd4_resetpriority(),
1083 * and not here, but we must still ensure that a
1084 * cpu-bound nice -20 process does not completely
1085 * override a cpu-bound nice +20 process.
1087 * NOTE: We must use ESTCPULIM() here to deal with any
1090 decay_factor = usched_bsd4_decay;
1091 if (decay_factor < 1)
1093 if (decay_factor > 1024)
1094 decay_factor = 1024;
1096 lp->lwp_estcpu = ESTCPULIM(
1097 (lp->lwp_estcpu * decay_factor + estcpu) /
1098 (decay_factor + 1));
1100 if (usched_bsd4_debug == lp->lwp_proc->p_pid)
1101 kprintf(" finalestcpu %d\n", lp->lwp_estcpu);
1102 bsd4_resetpriority(lp);
1103 lp->lwp_cpbase += ttlticks * gd->gd_schedclock.periodic;
1104 lp->lwp_cpticks = 0;
1109 * Compute the priority of a process when running in user mode.
1110 * Arrange to reschedule if the resulting priority is better
1111 * than that of the current process.
1113 * This routine may be called with any process.
1115 * This routine is called by fork1() for initial setup with the process
1116 * of the run queue, and also may be called normally with the process on or
1117 * off the run queue.
1122 bsd4_resetpriority(struct lwp *lp)
1132 * Calculate the new priority and queue type
1135 spin_lock(&bsd4_spin);
1137 newrqtype = lp->lwp_rtprio.type;
1140 case RTP_PRIO_REALTIME:
1142 newpriority = PRIBASE_REALTIME +
1143 (lp->lwp_rtprio.prio & PRIMASK);
1145 case RTP_PRIO_NORMAL:
1147 * Detune estcpu based on batchiness. lwp_batch ranges
1148 * from 0 to BATCHMAX. Limit estcpu for the sake of
1149 * the priority calculation to between 50% and 100%.
1151 estcpu = lp->lwp_estcpu * (lp->lwp_batch + BATCHMAX) /
1155 * p_nice piece Adds (0-40) * 2 0-80
1156 * estcpu Adds 16384 * 4 / 512 0-128
1158 newpriority = (lp->lwp_proc->p_nice - PRIO_MIN) * PPQ / NICEPPQ;
1159 newpriority += estcpu * PPQ / ESTCPUPPQ;
1160 newpriority = newpriority * MAXPRI / (PRIO_RANGE * PPQ /
1161 NICEPPQ + ESTCPUMAX * PPQ / ESTCPUPPQ);
1162 newpriority = PRIBASE_NORMAL + (newpriority & PRIMASK);
1165 newpriority = PRIBASE_IDLE + (lp->lwp_rtprio.prio & PRIMASK);
1167 case RTP_PRIO_THREAD:
1168 newpriority = PRIBASE_THREAD + (lp->lwp_rtprio.prio & PRIMASK);
1171 panic("Bad RTP_PRIO %d", newrqtype);
1176 * The newpriority incorporates the queue type so do a simple masked
1177 * check to determine if the process has moved to another queue. If
1178 * it has, and it is currently on a run queue, then move it.
1180 * td_upri has normal sense (higher values are more desireable), so
1183 lp->lwp_thread->td_upri = -(newpriority & ~PPQMASK);
1184 if ((lp->lwp_priority ^ newpriority) & ~PPQMASK) {
1185 lp->lwp_priority = newpriority;
1186 if (lp->lwp_mpflags & LWP_MP_ONRUNQ) {
1187 bsd4_remrunqueue_locked(lp);
1188 lp->lwp_rqtype = newrqtype;
1189 lp->lwp_rqindex = (newpriority & PRIMASK) / PPQ;
1190 bsd4_setrunqueue_locked(lp);
1193 lp->lwp_rqtype = newrqtype;
1194 lp->lwp_rqindex = (newpriority & PRIMASK) / PPQ;
1197 reschedcpu = lp->lwp_thread->td_gd->gd_cpuid;
1199 lp->lwp_priority = newpriority;
1205 * Determine if we need to reschedule the target cpu. This only
1206 * occurs if the LWP is already on a scheduler queue, which means
1207 * that idle cpu notification has already occured. At most we
1208 * need only issue a need_user_resched() on the appropriate cpu.
1210 * The LWP may be owned by a CPU different from the current one,
1211 * in which case dd->uschedcp may be modified without an MP lock
1212 * or a spinlock held. The worst that happens is that the code
1213 * below causes a spurious need_user_resched() on the target CPU
1214 * and dd->pri to be wrong for a short period of time, both of
1215 * which are harmless.
1217 * If checkpri is 0 we are adjusting the priority of the current
1218 * process, possibly higher (less desireable), so ignore the upri
1219 * check which will fail in that case.
1221 if (reschedcpu >= 0) {
1222 dd = &bsd4_pcpu[reschedcpu];
1223 if ((bsd4_rdyprocmask & CPUMASK(reschedcpu)) &&
1225 (dd->upri & ~PRIMASK) > (lp->lwp_priority & ~PRIMASK))) {
1227 if (reschedcpu == mycpu->gd_cpuid) {
1228 spin_unlock(&bsd4_spin);
1229 need_user_resched();
1231 spin_unlock(&bsd4_spin);
1232 atomic_clear_cpumask(&bsd4_rdyprocmask,
1233 CPUMASK(reschedcpu));
1234 lwkt_send_ipiq(lp->lwp_thread->td_gd,
1235 bsd4_need_user_resched_remote,
1239 spin_unlock(&bsd4_spin);
1240 need_user_resched();
1243 spin_unlock(&bsd4_spin);
1246 spin_unlock(&bsd4_spin);
1256 bsd4_yield(struct lwp *lp)
1259 /* FUTURE (or something similar) */
1260 switch(lp->lwp_rqtype) {
1261 case RTP_PRIO_NORMAL:
1262 lp->lwp_estcpu = ESTCPULIM(lp->lwp_estcpu + ESTCPUINCR);
1268 need_user_resched();
1272 * Called from fork1() when a new child process is being created.
1274 * Give the child process an initial estcpu that is more batch then
1275 * its parent and dock the parent for the fork (but do not
1276 * reschedule the parent). This comprises the main part of our batch
1277 * detection heuristic for both parallel forking and sequential execs.
1279 * XXX lwp should be "spawning" instead of "forking"
1284 bsd4_forking(struct lwp *plp, struct lwp *lp)
1287 * Put the child 4 queue slots (out of 32) higher than the parent
1288 * (less desireable than the parent).
1290 lp->lwp_estcpu = ESTCPULIM(plp->lwp_estcpu + ESTCPUPPQ * 4);
1293 * The batch status of children always starts out centerline
1294 * and will inch-up or inch-down as appropriate. It takes roughly
1295 * ~15 seconds of >50% cpu to hit the limit.
1297 lp->lwp_batch = BATCHMAX / 2;
1300 * Dock the parent a cost for the fork, protecting us from fork
1301 * bombs. If the parent is forking quickly make the child more
1304 plp->lwp_estcpu = ESTCPULIM(plp->lwp_estcpu + ESTCPUPPQ / 16);
1308 * Called when a lwp is being removed from this scheduler, typically
1309 * during lwp_exit().
1312 bsd4_exiting(struct lwp *lp, struct proc *child_proc)
1317 bsd4_uload_update(struct lwp *lp)
1322 * chooseproc() is called when a cpu needs a user process to LWKT schedule,
1323 * it selects a user process and returns it. If chklp is non-NULL and chklp
1324 * has a better or equal priority then the process that would otherwise be
1325 * chosen, NULL is returned.
1327 * Until we fix the RUNQ code the chklp test has to be strict or we may
1328 * bounce between processes trying to acquire the current process designation.
1330 * MPSAFE - must be called with bsd4_spin exclusive held. The spinlock is
1331 * left intact through the entire routine.
1335 bsd4_chooseproc_locked(struct lwp *chklp)
1339 u_int32_t *which, *which2;
1346 rtqbits = bsd4_rtqueuebits;
1347 tsqbits = bsd4_queuebits;
1348 idqbits = bsd4_idqueuebits;
1349 cpumask = mycpu->gd_cpumask;
1356 pri = bsfl(rtqbits);
1357 q = &bsd4_rtqueues[pri];
1358 which = &bsd4_rtqueuebits;
1360 } else if (tsqbits) {
1361 pri = bsfl(tsqbits);
1362 q = &bsd4_queues[pri];
1363 which = &bsd4_queuebits;
1365 } else if (idqbits) {
1366 pri = bsfl(idqbits);
1367 q = &bsd4_idqueues[pri];
1368 which = &bsd4_idqueuebits;
1373 lp = TAILQ_FIRST(q);
1374 KASSERT(lp, ("chooseproc: no lwp on busy queue"));
1377 while ((lp->lwp_cpumask & cpumask) == 0) {
1378 lp = TAILQ_NEXT(lp, lwp_procq);
1380 *which2 &= ~(1 << pri);
1387 * If the passed lwp <chklp> is reasonably close to the selected
1388 * lwp <lp>, return NULL (indicating that <chklp> should be kept).
1390 * Note that we must error on the side of <chklp> to avoid bouncing
1391 * between threads in the acquire code.
1394 if (chklp->lwp_priority < lp->lwp_priority + PPQ)
1400 * If the chosen lwp does not reside on this cpu spend a few
1401 * cycles looking for a better candidate at the same priority level.
1402 * This is a fallback check, setrunqueue() tries to wakeup the
1403 * correct cpu and is our front-line affinity.
1405 if (lp->lwp_thread->td_gd != mycpu &&
1406 (chklp = TAILQ_NEXT(lp, lwp_procq)) != NULL
1408 if (chklp->lwp_thread->td_gd == mycpu) {
1414 KTR_COND_LOG(usched_chooseproc,
1415 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
1416 lp->lwp_proc->p_pid,
1417 lp->lwp_thread->td_gd->gd_cpuid,
1420 TAILQ_REMOVE(q, lp, lwp_procq);
1423 *which &= ~(1 << pri);
1424 KASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) != 0, ("not on runq6!"));
1425 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ);
1432 * chooseproc() - with a cache coherence heuristic. Try to pull a process that
1433 * has its home on the current CPU> If the process doesn't have its home here
1434 * and is a batchy one (see batcy_looser_pri_test), we can wait for a
1435 * sched_tick, may be its home will become free and pull it in. Anyway,
1436 * we can't wait more than one tick. If that tick expired, we pull in that
1437 * process, no matter what.
1441 bsd4_chooseproc_locked_cache_coherent(struct lwp *chklp)
1445 u_int32_t *which, *which2;
1453 struct lwp * min_level_lwp = NULL;
1454 struct rq *min_q = NULL;
1456 cpu_node_t* cpunode = NULL;
1457 u_int32_t min_level = MAXCPU; /* number of levels < MAXCPU */
1458 u_int32_t *min_which = NULL;
1459 u_int32_t min_pri = 0;
1460 u_int32_t level = 0;
1462 rtqbits = bsd4_rtqueuebits;
1463 tsqbits = bsd4_queuebits;
1464 idqbits = bsd4_idqueuebits;
1465 cpumask = mycpu->gd_cpumask;
1467 /* Get the mask coresponding to the sysctl configured level */
1468 cpunode = bsd4_pcpu[mycpu->gd_cpuid].cpunode;
1469 level = usched_bsd4_stick_to_level;
1471 cpunode = cpunode->parent_node;
1474 /* The cpus which can ellect a process */
1475 siblings = cpunode->members;
1480 pri = bsfl(rtqbits);
1481 q = &bsd4_rtqueues[pri];
1482 which = &bsd4_rtqueuebits;
1484 } else if (tsqbits) {
1485 pri = bsfl(tsqbits);
1486 q = &bsd4_queues[pri];
1487 which = &bsd4_queuebits;
1489 } else if (idqbits) {
1490 pri = bsfl(idqbits);
1491 q = &bsd4_idqueues[pri];
1492 which = &bsd4_idqueuebits;
1496 * No more left and we didn't reach the checks limit.
1498 bsd4_kick_helper(min_level_lwp);
1501 lp = TAILQ_FIRST(q);
1502 KASSERT(lp, ("chooseproc: no lwp on busy queue"));
1505 * Limit the number of checks/queue to a configurable value to
1506 * minimize the contention (we are in a locked region
1508 while (checks < usched_bsd4_queue_checks) {
1509 if ((lp->lwp_cpumask & cpumask) == 0 ||
1510 ((siblings & lp->lwp_thread->td_gd->gd_cpumask) == 0 &&
1511 (lp->lwp_rebal_ticks == sched_ticks ||
1512 lp->lwp_rebal_ticks == (int)(sched_ticks - 1)) &&
1513 bsd4_batchy_looser_pri_test(lp))) {
1515 KTR_COND_LOG(usched_chooseproc_cc_not_good,
1516 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
1517 lp->lwp_proc->p_pid,
1518 (unsigned long)lp->lwp_thread->td_gd->gd_cpumask,
1519 (unsigned long)siblings,
1520 (unsigned long)cpumask);
1522 cpunode = bsd4_pcpu[lp->lwp_thread->td_gd->gd_cpuid].cpunode;
1525 if (cpunode->members & cpumask)
1527 cpunode = cpunode->parent_node;
1530 if (level < min_level ||
1531 (level == min_level && min_level_lwp &&
1532 lp->lwp_priority < min_level_lwp->lwp_priority)) {
1533 bsd4_kick_helper(min_level_lwp);
1540 bsd4_kick_helper(lp);
1542 lp = TAILQ_NEXT(lp, lwp_procq);
1544 *which2 &= ~(1 << pri);
1548 KTR_COND_LOG(usched_chooseproc_cc_elected,
1549 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
1550 lp->lwp_proc->p_pid,
1551 (unsigned long)lp->lwp_thread->td_gd->gd_cpumask,
1552 (unsigned long)siblings,
1553 (unsigned long)cpumask);
1561 * Checks exhausted, we tried to defer too many threads, so schedule
1562 * the best of the worst.
1568 KASSERT(lp, ("chooseproc: at least the first lp was good"));
1573 * If the passed lwp <chklp> is reasonably close to the selected
1574 * lwp <lp>, return NULL (indicating that <chklp> should be kept).
1576 * Note that we must error on the side of <chklp> to avoid bouncing
1577 * between threads in the acquire code.
1580 if (chklp->lwp_priority < lp->lwp_priority + PPQ) {
1581 bsd4_kick_helper(lp);
1586 KTR_COND_LOG(usched_chooseproc_cc,
1587 lp->lwp_proc->p_pid == usched_bsd4_pid_debug,
1588 lp->lwp_proc->p_pid,
1589 lp->lwp_thread->td_gd->gd_cpuid,
1592 TAILQ_REMOVE(q, lp, lwp_procq);
1595 *which &= ~(1 << pri);
1596 KASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) != 0, ("not on runq6!"));
1597 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ);
1603 * If we aren't willing to schedule a ready process on our cpu, give it's
1604 * target cpu a kick rather than wait for the next tick.
1606 * Called with bsd4_spin held.
1610 bsd4_kick_helper(struct lwp *lp)
1617 gd = lp->lwp_thread->td_gd;
1618 dd = &bsd4_pcpu[gd->gd_cpuid];
1619 if ((smp_active_mask & usched_global_cpumask &
1620 bsd4_rdyprocmask & gd->gd_cpumask) == 0) {
1623 ++usched_bsd4_kicks;
1624 atomic_clear_cpumask(&bsd4_rdyprocmask, gd->gd_cpumask);
1625 if ((dd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK)) {
1626 lwkt_send_ipiq(gd, bsd4_need_user_resched_remote, NULL);
1628 wakeup(&dd->helper_thread);
1634 bsd4_need_user_resched_remote(void *dummy)
1636 globaldata_t gd = mycpu;
1637 bsd4_pcpu_t dd = &bsd4_pcpu[gd->gd_cpuid];
1639 need_user_resched();
1641 /* Call wakeup_mycpu to avoid sending IPIs to other CPUs */
1642 wakeup_mycpu(&dd->helper_thread);
1648 * bsd4_remrunqueue_locked() removes a given process from the run queue
1649 * that it is on, clearing the queue busy bit if it becomes empty.
1651 * Note that user process scheduler is different from the LWKT schedule.
1652 * The user process scheduler only manages user processes but it uses LWKT
1653 * underneath, and a user process operating in the kernel will often be
1654 * 'released' from our management.
1656 * MPSAFE - bsd4_spin must be held exclusively on call
1659 bsd4_remrunqueue_locked(struct lwp *lp)
1665 KKASSERT(lp->lwp_mpflags & LWP_MP_ONRUNQ);
1666 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ);
1668 KKASSERT(bsd4_runqcount >= 0);
1670 pri = lp->lwp_rqindex;
1671 switch(lp->lwp_rqtype) {
1672 case RTP_PRIO_NORMAL:
1673 q = &bsd4_queues[pri];
1674 which = &bsd4_queuebits;
1676 case RTP_PRIO_REALTIME:
1678 q = &bsd4_rtqueues[pri];
1679 which = &bsd4_rtqueuebits;
1682 q = &bsd4_idqueues[pri];
1683 which = &bsd4_idqueuebits;
1686 panic("remrunqueue: invalid rtprio type");
1689 TAILQ_REMOVE(q, lp, lwp_procq);
1690 if (TAILQ_EMPTY(q)) {
1691 KASSERT((*which & (1 << pri)) != 0,
1692 ("remrunqueue: remove from empty queue"));
1693 *which &= ~(1 << pri);
1698 * bsd4_setrunqueue_locked()
1700 * Add a process whos rqtype and rqindex had previously been calculated
1701 * onto the appropriate run queue. Determine if the addition requires
1702 * a reschedule on a cpu and return the cpuid or -1.
1704 * NOTE: Lower priorities are better priorities.
1706 * MPSAFE - bsd4_spin must be held exclusively on call
1709 bsd4_setrunqueue_locked(struct lwp *lp)
1715 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0);
1716 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ);
1719 pri = lp->lwp_rqindex;
1721 switch(lp->lwp_rqtype) {
1722 case RTP_PRIO_NORMAL:
1723 q = &bsd4_queues[pri];
1724 which = &bsd4_queuebits;
1726 case RTP_PRIO_REALTIME:
1728 q = &bsd4_rtqueues[pri];
1729 which = &bsd4_rtqueuebits;
1732 q = &bsd4_idqueues[pri];
1733 which = &bsd4_idqueuebits;
1736 panic("remrunqueue: invalid rtprio type");
1741 * Add to the correct queue and set the appropriate bit. If no
1742 * lower priority (i.e. better) processes are in the queue then
1743 * we want a reschedule, calculate the best cpu for the job.
1745 * Always run reschedules on the LWPs original cpu.
1747 TAILQ_INSERT_TAIL(q, lp, lwp_procq);
1754 * For SMP systems a user scheduler helper thread is created for each
1755 * cpu and is used to allow one cpu to wakeup another for the purposes of
1756 * scheduling userland threads from setrunqueue().
1758 * UP systems do not need the helper since there is only one cpu.
1760 * We can't use the idle thread for this because we might block.
1761 * Additionally, doing things this way allows us to HLT idle cpus
1767 sched_thread(void *dummy)
1779 cpuid = gd->gd_cpuid; /* doesn't change */
1780 mask = gd->gd_cpumask; /* doesn't change */
1781 dd = &bsd4_pcpu[cpuid];
1784 * Since we are woken up only when no user processes are scheduled
1785 * on a cpu, we can run at an ultra low priority.
1787 lwkt_setpri_self(TDPRI_USER_SCHEDULER);
1789 tsleep(&dd->helper_thread, 0, "sched_thread_sleep", 0);
1793 * We use the LWKT deschedule-interlock trick to avoid racing
1794 * bsd4_rdyprocmask. This means we cannot block through to the
1795 * manual lwkt_switch() call we make below.
1798 tsleep_interlock(&dd->helper_thread, 0);
1799 spin_lock(&bsd4_spin);
1800 atomic_set_cpumask(&bsd4_rdyprocmask, mask);
1802 clear_user_resched(); /* This satisfied the reschedule request */
1803 dd->rrcount = 0; /* Reset the round-robin counter */
1805 if ((bsd4_curprocmask & mask) == 0) {
1807 * No thread is currently scheduled.
1809 KKASSERT(dd->uschedcp == NULL);
1810 if ((nlp = bsd4_chooseproc_locked(NULL)) != NULL) {
1811 KTR_COND_LOG(usched_sched_thread_no_process,
1812 nlp->lwp_proc->p_pid == usched_bsd4_pid_debug,
1814 nlp->lwp_proc->p_pid,
1815 nlp->lwp_thread->td_gd->gd_cpuid);
1817 atomic_set_cpumask(&bsd4_curprocmask, mask);
1818 dd->upri = nlp->lwp_priority;
1820 dd->rrcount = 0; /* reset round robin */
1821 spin_unlock(&bsd4_spin);
1822 lwkt_acquire(nlp->lwp_thread);
1823 lwkt_schedule(nlp->lwp_thread);
1825 spin_unlock(&bsd4_spin);
1827 } else if (bsd4_runqcount) {
1828 if ((nlp = bsd4_chooseproc_locked(dd->uschedcp)) != NULL) {
1829 KTR_COND_LOG(usched_sched_thread_process,
1830 nlp->lwp_proc->p_pid == usched_bsd4_pid_debug,
1832 nlp->lwp_proc->p_pid,
1833 nlp->lwp_thread->td_gd->gd_cpuid);
1835 dd->upri = nlp->lwp_priority;
1837 dd->rrcount = 0; /* reset round robin */
1838 spin_unlock(&bsd4_spin);
1839 lwkt_acquire(nlp->lwp_thread);
1840 lwkt_schedule(nlp->lwp_thread);
1843 * CHAINING CONDITION TRAIN
1845 * We could not deal with the scheduler wakeup
1846 * request on this cpu, locate a ready scheduler
1847 * with no current lp assignment and chain to it.
1849 * This ensures that a wakeup race which fails due
1850 * to priority test does not leave other unscheduled
1851 * cpus idle when the runqueue is not empty.
1853 tmpmask = ~bsd4_curprocmask &
1854 bsd4_rdyprocmask & smp_active_mask;
1856 tmpid = BSFCPUMASK(tmpmask);
1857 tmpdd = &bsd4_pcpu[tmpid];
1858 atomic_clear_cpumask(&bsd4_rdyprocmask,
1860 spin_unlock(&bsd4_spin);
1861 wakeup(&tmpdd->helper_thread);
1863 spin_unlock(&bsd4_spin);
1866 KTR_LOG(usched_sched_thread_no_process_found,
1867 gd->gd_cpuid, (unsigned long)tmpmask);
1871 * The runq is empty.
1873 spin_unlock(&bsd4_spin);
1877 * We're descheduled unless someone scheduled us. Switch away.
1878 * Exiting the critical section will cause splz() to be called
1879 * for us if interrupts and such are pending.
1882 tsleep(&dd->helper_thread, PINTERLOCKED, "schslp", 0);
1886 /* sysctl stick_to_level parameter */
1888 sysctl_usched_bsd4_stick_to_level(SYSCTL_HANDLER_ARGS)
1892 new_val = usched_bsd4_stick_to_level;
1894 error = sysctl_handle_int(oidp, &new_val, 0, req);
1895 if (error != 0 || req->newptr == NULL)
1897 if (new_val > cpu_topology_levels_number - 1 || new_val < 0)
1899 usched_bsd4_stick_to_level = new_val;
1904 * Setup our scheduler helpers. Note that curprocmask bit 0 has already
1905 * been cleared by rqinit() and we should not mess with it further.
1908 sched_thread_cpu_init(void)
1912 int smt_not_supported = 0;
1913 int cache_coherent_not_supported = 0;
1916 kprintf("Start scheduler helpers on cpus:\n");
1918 sysctl_ctx_init(&usched_bsd4_sysctl_ctx);
1919 usched_bsd4_sysctl_tree =
1920 SYSCTL_ADD_NODE(&usched_bsd4_sysctl_ctx,
1921 SYSCTL_STATIC_CHILDREN(_kern), OID_AUTO,
1922 "usched_bsd4", CTLFLAG_RD, 0, "");
1924 for (i = 0; i < ncpus; ++i) {
1925 bsd4_pcpu_t dd = &bsd4_pcpu[i];
1926 cpumask_t mask = CPUMASK(i);
1928 if ((mask & smp_active_mask) == 0)
1931 dd->cpunode = get_cpu_node_by_cpuid(i);
1933 if (dd->cpunode == NULL) {
1934 smt_not_supported = 1;
1935 cache_coherent_not_supported = 1;
1937 kprintf ("\tcpu%d - WARNING: No CPU NODE "
1938 "found for cpu\n", i);
1940 switch (dd->cpunode->type) {
1943 kprintf ("\tcpu%d - HyperThreading "
1944 "available. Core siblings: ",
1948 smt_not_supported = 1;
1951 kprintf ("\tcpu%d - No HT available, "
1952 "multi-core/physical "
1953 "cpu. Physical siblings: ",
1957 smt_not_supported = 1;
1960 kprintf ("\tcpu%d - No HT available, "
1961 "single-core/physical cpu. "
1962 "Package Siblings: ",
1966 /* Let's go for safe defaults here */
1967 smt_not_supported = 1;
1968 cache_coherent_not_supported = 1;
1970 kprintf ("\tcpu%d - Unknown cpunode->"
1971 "type=%u. Siblings: ",
1973 (u_int)dd->cpunode->type);
1978 if (dd->cpunode->parent_node != NULL) {
1979 CPUSET_FOREACH(cpuid, dd->cpunode->parent_node->members)
1980 kprintf("cpu%d ", cpuid);
1983 kprintf(" no siblings\n");
1988 lwkt_create(sched_thread, NULL, NULL, &dd->helper_thread,
1989 0, i, "usched %d", i);
1992 * Allow user scheduling on the target cpu. cpu #0 has already
1993 * been enabled in rqinit().
1996 atomic_clear_cpumask(&bsd4_curprocmask, mask);
1997 atomic_set_cpumask(&bsd4_rdyprocmask, mask);
1998 dd->upri = PRIBASE_NULL;
2002 /* usched_bsd4 sysctl configurable parameters */
2004 SYSCTL_ADD_INT(&usched_bsd4_sysctl_ctx,
2005 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2006 OID_AUTO, "rrinterval", CTLFLAG_RW,
2007 &usched_bsd4_rrinterval, 0, "");
2008 SYSCTL_ADD_INT(&usched_bsd4_sysctl_ctx,
2009 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2010 OID_AUTO, "decay", CTLFLAG_RW,
2011 &usched_bsd4_decay, 0, "Extra decay when not running");
2012 SYSCTL_ADD_INT(&usched_bsd4_sysctl_ctx,
2013 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2014 OID_AUTO, "batch_time", CTLFLAG_RW,
2015 &usched_bsd4_batch_time, 0, "Min batch counter value");
2016 SYSCTL_ADD_LONG(&usched_bsd4_sysctl_ctx,
2017 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2018 OID_AUTO, "kicks", CTLFLAG_RW,
2019 &usched_bsd4_kicks, "Number of kickstarts");
2021 /* Add enable/disable option for SMT scheduling if supported */
2022 if (smt_not_supported) {
2023 usched_bsd4_smt = 0;
2024 SYSCTL_ADD_STRING(&usched_bsd4_sysctl_ctx,
2025 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2026 OID_AUTO, "smt", CTLFLAG_RD,
2027 "NOT SUPPORTED", 0, "SMT NOT SUPPORTED");
2029 usched_bsd4_smt = 1;
2030 SYSCTL_ADD_INT(&usched_bsd4_sysctl_ctx,
2031 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2032 OID_AUTO, "smt", CTLFLAG_RW,
2033 &usched_bsd4_smt, 0, "Enable SMT scheduling");
2037 * Add enable/disable option for cache coherent scheduling
2040 if (cache_coherent_not_supported) {
2041 usched_bsd4_cache_coherent = 0;
2042 SYSCTL_ADD_STRING(&usched_bsd4_sysctl_ctx,
2043 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2044 OID_AUTO, "cache_coherent", CTLFLAG_RD,
2046 "Cache coherence NOT SUPPORTED");
2048 usched_bsd4_cache_coherent = 1;
2049 SYSCTL_ADD_INT(&usched_bsd4_sysctl_ctx,
2050 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2051 OID_AUTO, "cache_coherent", CTLFLAG_RW,
2052 &usched_bsd4_cache_coherent, 0,
2053 "Enable/Disable cache coherent scheduling");
2055 SYSCTL_ADD_INT(&usched_bsd4_sysctl_ctx,
2056 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2057 OID_AUTO, "upri_affinity", CTLFLAG_RW,
2058 &usched_bsd4_upri_affinity, 1,
2059 "Number of PPQs in user priority check");
2061 SYSCTL_ADD_INT(&usched_bsd4_sysctl_ctx,
2062 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2063 OID_AUTO, "queue_checks", CTLFLAG_RW,
2064 &usched_bsd4_queue_checks, 5,
2065 "LWPs to check from a queue before giving up");
2067 SYSCTL_ADD_PROC(&usched_bsd4_sysctl_ctx,
2068 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2069 OID_AUTO, "stick_to_level",
2070 CTLTYPE_INT | CTLFLAG_RW,
2071 NULL, sizeof usched_bsd4_stick_to_level,
2072 sysctl_usched_bsd4_stick_to_level, "I",
2073 "Stick a process to this level. See sysctl"
2074 "paremter hw.cpu_topology.level_description");
2077 SYSINIT(uschedtd, SI_BOOT2_USCHED, SI_ORDER_SECOND,
2078 sched_thread_cpu_init, NULL)
2080 #else /* No SMP options - just add the configurable parameters to sysctl */
2083 sched_sysctl_tree_init(void)
2085 sysctl_ctx_init(&usched_bsd4_sysctl_ctx);
2086 usched_bsd4_sysctl_tree =
2087 SYSCTL_ADD_NODE(&usched_bsd4_sysctl_ctx,
2088 SYSCTL_STATIC_CHILDREN(_kern), OID_AUTO,
2089 "usched_bsd4", CTLFLAG_RD, 0, "");
2091 /* usched_bsd4 sysctl configurable parameters */
2092 SYSCTL_ADD_INT(&usched_bsd4_sysctl_ctx,
2093 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2094 OID_AUTO, "rrinterval", CTLFLAG_RW,
2095 &usched_bsd4_rrinterval, 0, "");
2096 SYSCTL_ADD_INT(&usched_bsd4_sysctl_ctx,
2097 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2098 OID_AUTO, "decay", CTLFLAG_RW,
2099 &usched_bsd4_decay, 0, "Extra decay when not running");
2100 SYSCTL_ADD_INT(&usched_bsd4_sysctl_ctx,
2101 SYSCTL_CHILDREN(usched_bsd4_sysctl_tree),
2102 OID_AUTO, "batch_time", CTLFLAG_RW,
2103 &usched_bsd4_batch_time, 0, "Min batch counter value");
2105 SYSINIT(uschedtd, SI_BOOT2_USCHED, SI_ORDER_SECOND,
2106 sched_sysctl_tree_init, NULL)