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_rqindex lwp_usdata.dfly.rqindex
94 #define lwp_estcpu lwp_usdata.dfly.estcpu
95 #define lwp_batch lwp_usdata.dfly.batch
96 #define lwp_rqtype lwp_usdata.dfly.rqtype
97 #define lwp_qcpu lwp_usdata.dfly.qcpu
99 struct usched_dfly_pcpu {
100 struct spinlock spin;
101 struct thread helper_thread;
105 struct lwp *uschedcp;
106 struct rq queues[NQS];
107 struct rq rtqueues[NQS];
108 struct rq idqueues[NQS];
110 u_int32_t rtqueuebits;
111 u_int32_t idqueuebits;
120 typedef struct usched_dfly_pcpu *dfly_pcpu_t;
122 static void dfly_acquire_curproc(struct lwp *lp);
123 static void dfly_release_curproc(struct lwp *lp);
124 static void dfly_select_curproc(globaldata_t gd);
125 static void dfly_setrunqueue(struct lwp *lp);
126 static void dfly_schedulerclock(struct lwp *lp, sysclock_t period,
128 static void dfly_recalculate_estcpu(struct lwp *lp);
129 static void dfly_resetpriority(struct lwp *lp);
130 static void dfly_forking(struct lwp *plp, struct lwp *lp);
131 static void dfly_exiting(struct lwp *lp, struct proc *);
132 static void dfly_uload_update(struct lwp *lp);
133 static void dfly_yield(struct lwp *lp);
135 static dfly_pcpu_t dfly_choose_best_queue(dfly_pcpu_t dd, struct lwp *lp);
136 static dfly_pcpu_t dfly_choose_worst_queue(dfly_pcpu_t dd);
137 static dfly_pcpu_t dfly_choose_queue_simple(dfly_pcpu_t dd, struct lwp *lp);
141 static void dfly_need_user_resched_remote(void *dummy);
143 static struct lwp *dfly_chooseproc_locked(dfly_pcpu_t dd, struct lwp *chklp,
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);
148 struct usched usched_dfly = {
150 "dfly", "Original DragonFly Scheduler",
151 NULL, /* default registration */
152 NULL, /* default deregistration */
153 dfly_acquire_curproc,
154 dfly_release_curproc,
157 dfly_recalculate_estcpu,
162 NULL, /* setcpumask not supported */
167 * We have NQS (32) run queues per scheduling class. For the normal
168 * class, there are 128 priorities scaled onto these 32 queues. New
169 * processes are added to the last entry in each queue, and processes
170 * are selected for running by taking them from the head and maintaining
171 * a simple FIFO arrangement. Realtime and Idle priority processes have
172 * and explicit 0-31 priority which maps directly onto their class queue
173 * index. When a queue has something in it, the corresponding bit is
174 * set in the queuebits variable, allowing a single read to determine
175 * the state of all 32 queues and then a ffs() to find the first busy
178 static cpumask_t dfly_curprocmask = -1; /* currently running a user process */
179 static cpumask_t dfly_rdyprocmask; /* ready to accept a user process */
181 static volatile int dfly_scancpu;
182 /*static struct spinlock dfly_spin = SPINLOCK_INITIALIZER(dfly_spin);*/
184 static struct usched_dfly_pcpu dfly_pcpu[MAXCPU];
185 static struct sysctl_ctx_list usched_dfly_sysctl_ctx;
186 static struct sysctl_oid *usched_dfly_sysctl_tree;
188 /* Debug info exposed through debug.* sysctl */
190 static int usched_dfly_debug = -1;
191 SYSCTL_INT(_debug, OID_AUTO, dfly_scdebug, CTLFLAG_RW,
192 &usched_dfly_debug, 0,
193 "Print debug information for this pid");
195 static int usched_dfly_pid_debug = -1;
196 SYSCTL_INT(_debug, OID_AUTO, dfly_pid_debug, CTLFLAG_RW,
197 &usched_dfly_pid_debug, 0,
198 "Print KTR debug information for this pid");
200 static int usched_dfly_chooser = 0;
201 SYSCTL_INT(_debug, OID_AUTO, dfly_chooser, CTLFLAG_RW,
202 &usched_dfly_chooser, 0,
203 "Print KTR debug information for this pid");
205 /* Tunning usched_dfly - configurable through kern.usched_dfly.* */
207 static int usched_dfly_smt = 0;
208 static int usched_dfly_cache_coherent = 0;
209 static int usched_dfly_upri_affinity = 16; /* 32 queues - half-way */
210 static int usched_dfly_queue_checks = 5;
211 static int usched_dfly_stick_to_level = 0;
213 static int usched_dfly_rrinterval = (ESTCPUFREQ + 9) / 10;
214 static int usched_dfly_decay = 8;
215 static int usched_dfly_batch_time = 10;
217 /* KTR debug printings */
219 KTR_INFO_MASTER(usched);
221 #if !defined(KTR_USCHED_DFLY)
222 #define KTR_USCHED_DFLY KTR_ALL
225 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_acquire_curproc_urw, 0,
226 "USCHED_DFLY(dfly_acquire_curproc in user_reseched_wanted "
227 "after release: pid %d, cpuid %d, curr_cpuid %d)",
228 pid_t pid, int cpuid, int curr);
229 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_acquire_curproc_before_loop, 0,
230 "USCHED_DFLY(dfly_acquire_curproc before loop: pid %d, cpuid %d, "
232 pid_t pid, int cpuid, int curr);
233 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_acquire_curproc_not, 0,
234 "USCHED_DFLY(dfly_acquire_curproc couldn't acquire after "
235 "dfly_setrunqueue: pid %d, cpuid %d, curr_lp pid %d, curr_cpuid %d)",
236 pid_t pid, int cpuid, pid_t curr_pid, int curr_cpuid);
237 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_acquire_curproc_switch, 0,
238 "USCHED_DFLY(dfly_acquire_curproc after lwkt_switch: pid %d, "
239 "cpuid %d, curr_cpuid %d)",
240 pid_t pid, int cpuid, int curr);
242 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_release_curproc, 0,
243 "USCHED_DFLY(dfly_release_curproc before select: pid %d, "
244 "cpuid %d, curr_cpuid %d)",
245 pid_t pid, int cpuid, int curr);
247 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_select_curproc, 0,
248 "USCHED_DFLY(dfly_release_curproc before select: pid %d, "
249 "cpuid %d, old_pid %d, old_cpuid %d, curr_cpuid %d)",
250 pid_t pid, int cpuid, pid_t old_pid, int old_cpuid, int curr);
253 KTR_INFO(KTR_USCHED_DFLY, usched, batchy_test_false, 0,
254 "USCHED_DFLY(batchy_looser_pri_test false: pid %d, "
255 "cpuid %d, verify_mask %lu)",
256 pid_t pid, int cpuid, cpumask_t mask);
257 KTR_INFO(KTR_USCHED_DFLY, usched, batchy_test_true, 0,
258 "USCHED_DFLY(batchy_looser_pri_test true: pid %d, "
259 "cpuid %d, verify_mask %lu)",
260 pid_t pid, int cpuid, cpumask_t mask);
262 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_setrunqueue_fc_smt, 0,
263 "USCHED_DFLY(dfly_setrunqueue free cpus smt: pid %d, cpuid %d, "
264 "mask %lu, curr_cpuid %d)",
265 pid_t pid, int cpuid, cpumask_t mask, int curr);
266 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_setrunqueue_fc_non_smt, 0,
267 "USCHED_DFLY(dfly_setrunqueue free cpus check non_smt: pid %d, "
268 "cpuid %d, mask %lu, curr_cpuid %d)",
269 pid_t pid, int cpuid, cpumask_t mask, int curr);
270 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_setrunqueue_rc, 0,
271 "USCHED_DFLY(dfly_setrunqueue running cpus check: pid %d, "
272 "cpuid %d, mask %lu, curr_cpuid %d)",
273 pid_t pid, int cpuid, cpumask_t mask, int curr);
274 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_setrunqueue_found, 0,
275 "USCHED_DFLY(dfly_setrunqueue found cpu: pid %d, cpuid %d, "
276 "mask %lu, found_cpuid %d, curr_cpuid %d)",
277 pid_t pid, int cpuid, cpumask_t mask, int found_cpuid, int curr);
278 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_setrunqueue_not_found, 0,
279 "USCHED_DFLY(dfly_setrunqueue not found cpu: pid %d, cpuid %d, "
280 "try_cpuid %d, curr_cpuid %d)",
281 pid_t pid, int cpuid, int try_cpuid, int curr);
282 KTR_INFO(KTR_USCHED_DFLY, usched, dfly_setrunqueue_found_best_cpuid, 0,
283 "USCHED_DFLY(dfly_setrunqueue found cpu: pid %d, cpuid %d, "
284 "mask %lu, found_cpuid %d, curr_cpuid %d)",
285 pid_t pid, int cpuid, cpumask_t mask, int found_cpuid, int curr);
288 KTR_INFO(KTR_USCHED_DFLY, usched, chooseproc, 0,
289 "USCHED_DFLY(chooseproc: pid %d, old_cpuid %d, curr_cpuid %d)",
290 pid_t pid, int old_cpuid, int curr);
292 KTR_INFO(KTR_USCHED_DFLY, usched, chooseproc_cc, 0,
293 "USCHED_DFLY(chooseproc_cc: pid %d, old_cpuid %d, curr_cpuid %d)",
294 pid_t pid, int old_cpuid, int curr);
295 KTR_INFO(KTR_USCHED_DFLY, usched, chooseproc_cc_not_good, 0,
296 "USCHED_DFLY(chooseproc_cc not good: pid %d, old_cpumask %lu, "
297 "sibling_mask %lu, curr_cpumask %lu)",
298 pid_t pid, cpumask_t old_cpumask, cpumask_t sibling_mask, cpumask_t curr);
299 KTR_INFO(KTR_USCHED_DFLY, usched, chooseproc_cc_elected, 0,
300 "USCHED_DFLY(chooseproc_cc elected: pid %d, old_cpumask %lu, "
301 "sibling_mask %lu, curr_cpumask: %lu)",
302 pid_t pid, cpumask_t old_cpumask, cpumask_t sibling_mask, cpumask_t curr);
304 KTR_INFO(KTR_USCHED_DFLY, usched, sched_thread_no_process, 0,
305 "USCHED_DFLY(sched_thread %d no process scheduled: pid %d, old_cpuid %d)",
306 int id, pid_t pid, int cpuid);
307 KTR_INFO(KTR_USCHED_DFLY, usched, sched_thread_process, 0,
308 "USCHED_DFLY(sched_thread %d process scheduled: pid %d, old_cpuid %d)",
309 int id, pid_t pid, int cpuid);
310 KTR_INFO(KTR_USCHED_DFLY, usched, sched_thread_no_process_found, 0,
311 "USCHED_DFLY(sched_thread %d no process found; tmpmask %lu)",
312 int id, cpumask_t tmpmask);
316 * DFLY_ACQUIRE_CURPROC
318 * This function is called when the kernel intends to return to userland.
319 * It is responsible for making the thread the current designated userland
320 * thread for this cpu, blocking if necessary.
322 * The kernel has already depressed our LWKT priority so we must not switch
323 * until we have either assigned or disposed of the thread.
325 * WARNING! THIS FUNCTION IS ALLOWED TO CAUSE THE CURRENT THREAD TO MIGRATE
326 * TO ANOTHER CPU! Because most of the kernel assumes that no migration will
327 * occur, this function is called only under very controlled circumstances.
330 dfly_acquire_curproc(struct lwp *lp)
337 * Make sure we aren't sitting on a tsleep queue.
340 crit_enter_quick(td);
341 if (td->td_flags & TDF_TSLEEPQ)
343 dfly_recalculate_estcpu(lp);
346 * If a reschedule was requested give another thread the
349 if (user_resched_wanted()) {
350 clear_user_resched();
351 dfly_release_curproc(lp);
355 * Loop until we are the current user thread
358 dd = &dfly_pcpu[gd->gd_cpuid];
362 * Process any pending events and higher priority threads.
367 * Become the currently scheduled user thread for this cpu
368 * if we can do so trivially.
370 * We can steal another thread's current thread designation
371 * on this cpu since if we are running that other thread
372 * must not be, so we can safely deschedule it.
374 if (dd->uschedcp == lp) {
376 * We are already the current lwp (hot path).
378 dd->upri = lp->lwp_priority;
379 } else if (dd->uschedcp == NULL) {
381 * We can trivially become the current lwp.
383 atomic_set_cpumask(&dfly_curprocmask, gd->gd_cpumask);
385 dd->upri = lp->lwp_priority;
386 KKASSERT(lp->lwp_qcpu == dd->cpuid);
387 } else if (dd->uschedcp && dd->upri > lp->lwp_priority) {
389 * We can steal the current cpu's lwp designation
390 * away simply by replacing it. The other thread
391 * will stall when it tries to return to userland,
392 * possibly rescheduling elsewhere when it calls
396 dd->upri = lp->lwp_priority;
397 KKASSERT(lp->lwp_qcpu == dd->cpuid);
400 * We cannot become the current lwp, place the lp
401 * on the run-queue of this or another cpu and
402 * deschedule ourselves.
404 * When we are reactivated we will have another
407 lwkt_deschedule(lp->lwp_thread);
408 dfly_setrunqueue(lp);
411 * Reload after a switch or setrunqueue/switch possibly
412 * moved us to another cpu.
416 dd = &dfly_pcpu[gd->gd_cpuid];
418 } while (dd->uschedcp != lp);
421 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0);
425 * DFLY_RELEASE_CURPROC
427 * This routine detaches the current thread from the userland scheduler,
428 * usually because the thread needs to run or block in the kernel (at
429 * kernel priority) for a while.
431 * This routine is also responsible for selecting a new thread to
432 * make the current thread.
434 * NOTE: This implementation differs from the dummy example in that
435 * dfly_select_curproc() is able to select the current process, whereas
436 * dummy_select_curproc() is not able to select the current process.
437 * This means we have to NULL out uschedcp.
439 * Additionally, note that we may already be on a run queue if releasing
440 * via the lwkt_switch() in dfly_setrunqueue().
444 dfly_release_curproc(struct lwp *lp)
446 globaldata_t gd = mycpu;
447 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid];
449 if (dd->uschedcp == lp) {
451 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0);
453 dd->uschedcp = NULL; /* don't let lp be selected */
454 dd->upri = PRIBASE_NULL;
455 atomic_clear_cpumask(&dfly_curprocmask, gd->gd_cpumask);
456 dfly_select_curproc(gd);
462 * DFLY_SELECT_CURPROC
464 * Select a new current process for this cpu and clear any pending user
465 * reschedule request. The cpu currently has no current process.
467 * This routine is also responsible for equal-priority round-robining,
468 * typically triggered from dfly_schedulerclock(). In our dummy example
469 * all the 'user' threads are LWKT scheduled all at once and we just
470 * call lwkt_switch().
472 * The calling process is not on the queue and cannot be selected.
476 dfly_select_curproc(globaldata_t gd)
478 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid];
480 int cpuid = gd->gd_cpuid;
484 /*spin_lock(&dfly_spin);*/
485 spin_lock(&dd->spin);
486 nlp = dfly_chooseproc_locked(dd, dd->uschedcp, 0);
489 atomic_set_cpumask(&dfly_curprocmask, CPUMASK(cpuid));
490 dd->upri = nlp->lwp_priority;
492 dd->rrcount = 0; /* reset round robin */
493 spin_unlock(&dd->spin);
494 /*spin_unlock(&dfly_spin);*/
496 lwkt_acquire(nlp->lwp_thread);
498 lwkt_schedule(nlp->lwp_thread);
500 spin_unlock(&dd->spin);
501 /*spin_unlock(&dfly_spin);*/
507 * Place the specified lwp on the user scheduler's run queue. This routine
508 * must be called with the thread descheduled. The lwp must be runnable.
509 * It must not be possible for anyone else to explicitly schedule this thread.
511 * The thread may be the current thread as a special case.
514 dfly_setrunqueue(struct lwp *lp)
521 * First validate the process LWKT state.
524 KASSERT(lp->lwp_stat == LSRUN, ("setrunqueue: lwp not LSRUN"));
525 KASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0,
526 ("lwp %d/%d already on runq! flag %08x/%08x", lp->lwp_proc->p_pid,
527 lp->lwp_tid, lp->lwp_proc->p_flags, lp->lwp_flags));
528 KKASSERT((lp->lwp_thread->td_flags & TDF_RUNQ) == 0);
531 * NOTE: gd and dd are relative to the target thread's last cpu,
532 * NOT our current cpu.
534 rgd = globaldata_find(lp->lwp_qcpu);
535 rdd = &dfly_pcpu[lp->lwp_qcpu];
539 * This process is not supposed to be scheduled anywhere or assigned
540 * as the current process anywhere. Assert the condition.
542 KKASSERT(rdd->uschedcp != lp);
546 * If we are not SMP we do not have a scheduler helper to kick
547 * and must directly activate the process if none are scheduled.
549 * This is really only an issue when bootstrapping init since
550 * the caller in all other cases will be a user process, and
551 * even if released (rdd->uschedcp == NULL), that process will
552 * kickstart the scheduler when it returns to user mode from
555 * NOTE: On SMP we can't just set some other cpu's uschedcp.
557 if (rdd->uschedcp == NULL) {
558 spin_lock(&rdd->spin);
559 if (rdd->uschedcp == NULL) {
560 atomic_set_cpumask(&dfly_curprocmask, rgd->gd_cpumask);
562 rdd->upri = lp->lwp_priority;
563 spin_unlock(&rdd->spin);
564 lwkt_schedule(lp->lwp_thread);
568 spin_unlock(&rdd->spin);
574 * XXX fixme. Could be part of a remrunqueue/setrunqueue
575 * operation when the priority is recalculated, so TDF_MIGRATING
576 * may already be set.
578 if ((lp->lwp_thread->td_flags & TDF_MIGRATING) == 0)
579 lwkt_giveaway(lp->lwp_thread);
584 * Ok, we have to setrunqueue some target cpu and request a reschedule
587 * We have to choose the best target cpu. It might not be the current
588 * target even if the current cpu has no running user thread (for
589 * example, because the current cpu might be a hyperthread and its
590 * sibling has a thread assigned).
592 /*spin_lock(&dfly_spin);*/
593 rdd = dfly_choose_best_queue(rdd, lp);
594 rgd = globaldata_find(rdd->cpuid);
597 * We lose control of lp the moment we release the spinlock after
598 * having placed lp on the queue. i.e. another cpu could pick it
599 * up and it could exit, or its priority could be further adjusted,
600 * or something like that.
602 * WARNING! dd can point to a foreign cpu!
604 spin_lock(&rdd->spin);
605 dfly_setrunqueue_locked(rdd, lp);
606 /*spin_unlock(&dfly_spin);*/
609 if ((rdd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK)) {
610 spin_unlock(&rdd->spin);
611 if (rdd->uschedcp == NULL) {
612 wakeup_mycpu(&rdd->helper_thread); /* XXX */
618 spin_unlock(&rdd->spin);
621 atomic_clear_cpumask(&dfly_rdyprocmask, CPUMASK(cpuid));
622 if ((rdd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK)) {
623 spin_unlock(&rdd->spin);
624 lwkt_send_ipiq(rgd, dfly_need_user_resched_remote,
627 spin_unlock(&rdd->spin);
628 wakeup(&rdd->helper_thread);
633 * Request a reschedule if appropriate.
635 spin_lock(&rdd->spin);
636 dfly_setrunqueue_locked(rdd, lp);
637 spin_unlock(&rdd->spin);
638 if ((rdd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK)) {
646 * This routine is called from a systimer IPI. It MUST be MP-safe and
647 * the BGL IS NOT HELD ON ENTRY. This routine is called at ESTCPUFREQ on
652 dfly_schedulerclock(struct lwp *lp, sysclock_t period, sysclock_t cpstamp)
654 globaldata_t gd = mycpu;
655 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid];
658 * Do we need to round-robin? We round-robin 10 times a second.
659 * This should only occur for cpu-bound batch processes.
661 if (++dd->rrcount >= usched_dfly_rrinterval) {
667 * Adjust estcpu upward using a real time equivalent calculation.
669 lp->lwp_estcpu = ESTCPULIM(lp->lwp_estcpu + ESTCPUMAX / ESTCPUFREQ + 1);
672 * Spinlocks also hold a critical section so there should not be
675 KKASSERT(gd->gd_spinlocks_wr == 0);
677 dfly_resetpriority(lp);
681 * Called from acquire and from kern_synch's one-second timer (one of the
682 * callout helper threads) with a critical section held.
684 * Decay p_estcpu based on the number of ticks we haven't been running
685 * and our p_nice. As the load increases each process observes a larger
686 * number of idle ticks (because other processes are running in them).
687 * This observation leads to a larger correction which tends to make the
688 * system more 'batchy'.
690 * Note that no recalculation occurs for a process which sleeps and wakes
691 * up in the same tick. That is, a system doing thousands of context
692 * switches per second will still only do serious estcpu calculations
693 * ESTCPUFREQ times per second.
697 dfly_recalculate_estcpu(struct lwp *lp)
699 globaldata_t gd = mycpu;
700 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid];
707 * We have to subtract periodic to get the last schedclock
708 * timeout time, otherwise we would get the upcoming timeout.
709 * Keep in mind that a process can migrate between cpus and
710 * while the scheduler clock should be very close, boundary
711 * conditions could lead to a small negative delta.
713 cpbase = gd->gd_schedclock.time - gd->gd_schedclock.periodic;
715 if (lp->lwp_slptime > 1) {
717 * Too much time has passed, do a coarse correction.
719 lp->lwp_estcpu = lp->lwp_estcpu >> 1;
720 dfly_resetpriority(lp);
721 lp->lwp_cpbase = cpbase;
723 lp->lwp_batch -= ESTCPUFREQ;
724 if (lp->lwp_batch < 0)
726 } else if (lp->lwp_cpbase != cpbase) {
728 * Adjust estcpu if we are in a different tick. Don't waste
729 * time if we are in the same tick.
731 * First calculate the number of ticks in the measurement
732 * interval. The ttlticks calculation can wind up 0 due to
733 * a bug in the handling of lwp_slptime (as yet not found),
734 * so make sure we do not get a divide by 0 panic.
736 ttlticks = (cpbase - lp->lwp_cpbase) /
737 gd->gd_schedclock.periodic;
740 lp->lwp_cpbase = cpbase;
744 updatepcpu(lp, lp->lwp_cpticks, ttlticks);
747 * Calculate the percentage of one cpu used factoring in ncpus
748 * and the load and adjust estcpu. Handle degenerate cases
749 * by adding 1 to runqcount.
751 * estcpu is scaled by ESTCPUMAX.
753 * runqcount is the excess number of user processes
754 * that cannot be immediately scheduled to cpus. We want
755 * to count these as running to avoid range compression
756 * in the base calculation (which is the actual percentage
759 estcpu = (lp->lwp_cpticks * ESTCPUMAX) *
760 (dd->runqcount + ncpus) / (ncpus * ttlticks);
763 * If estcpu is > 50% we become more batch-like
764 * If estcpu is <= 50% we become less batch-like
766 * It takes 30 cpu seconds to traverse the entire range.
768 if (estcpu > ESTCPUMAX / 2) {
769 lp->lwp_batch += ttlticks;
770 if (lp->lwp_batch > BATCHMAX)
771 lp->lwp_batch = BATCHMAX;
773 lp->lwp_batch -= ttlticks;
774 if (lp->lwp_batch < 0)
778 if (usched_dfly_debug == lp->lwp_proc->p_pid) {
779 kprintf("pid %d lwp %p estcpu %3d %3d bat %d cp %d/%d",
780 lp->lwp_proc->p_pid, lp,
781 estcpu, lp->lwp_estcpu,
783 lp->lwp_cpticks, ttlticks);
787 * Adjust lp->lwp_esetcpu. The decay factor determines how
788 * quickly lwp_estcpu collapses to its realtime calculation.
789 * A slower collapse gives us a more accurate number but
790 * can cause a cpu hog to eat too much cpu before the
791 * scheduler decides to downgrade it.
793 * NOTE: p_nice is accounted for in dfly_resetpriority(),
794 * and not here, but we must still ensure that a
795 * cpu-bound nice -20 process does not completely
796 * override a cpu-bound nice +20 process.
798 * NOTE: We must use ESTCPULIM() here to deal with any
801 decay_factor = usched_dfly_decay;
802 if (decay_factor < 1)
804 if (decay_factor > 1024)
807 lp->lwp_estcpu = ESTCPULIM(
808 (lp->lwp_estcpu * decay_factor + estcpu) /
811 if (usched_dfly_debug == lp->lwp_proc->p_pid)
812 kprintf(" finalestcpu %d\n", lp->lwp_estcpu);
813 dfly_resetpriority(lp);
814 lp->lwp_cpbase += ttlticks * gd->gd_schedclock.periodic;
820 * Compute the priority of a process when running in user mode.
821 * Arrange to reschedule if the resulting priority is better
822 * than that of the current process.
824 * This routine may be called with any process.
826 * This routine is called by fork1() for initial setup with the process
827 * of the run queue, and also may be called normally with the process on or
831 dfly_resetpriority(struct lwp *lp)
843 * Lock the scheduler (lp) belongs to. This can be on a different
844 * cpu. Handle races. This loop breaks out with the appropriate
849 rdd = &dfly_pcpu[rcpu];
850 spin_lock(&rdd->spin);
851 if (rcpu == lp->lwp_qcpu)
853 spin_unlock(&rdd->spin);
857 * Calculate the new priority and queue type
859 newrqtype = lp->lwp_rtprio.type;
862 case RTP_PRIO_REALTIME:
864 newpriority = PRIBASE_REALTIME +
865 (lp->lwp_rtprio.prio & PRIMASK);
867 case RTP_PRIO_NORMAL:
869 * Detune estcpu based on batchiness. lwp_batch ranges
870 * from 0 to BATCHMAX. Limit estcpu for the sake of
871 * the priority calculation to between 50% and 100%.
873 estcpu = lp->lwp_estcpu * (lp->lwp_batch + BATCHMAX) /
877 * p_nice piece Adds (0-40) * 2 0-80
878 * estcpu Adds 16384 * 4 / 512 0-128
880 newpriority = (lp->lwp_proc->p_nice - PRIO_MIN) * PPQ / NICEPPQ;
881 newpriority += estcpu * PPQ / ESTCPUPPQ;
882 newpriority = newpriority * MAXPRI / (PRIO_RANGE * PPQ /
883 NICEPPQ + ESTCPUMAX * PPQ / ESTCPUPPQ);
884 newpriority = PRIBASE_NORMAL + (newpriority & PRIMASK);
887 newpriority = PRIBASE_IDLE + (lp->lwp_rtprio.prio & PRIMASK);
889 case RTP_PRIO_THREAD:
890 newpriority = PRIBASE_THREAD + (lp->lwp_rtprio.prio & PRIMASK);
893 panic("Bad RTP_PRIO %d", newrqtype);
898 * The newpriority incorporates the queue type so do a simple masked
899 * check to determine if the process has moved to another queue. If
900 * it has, and it is currently on a run queue, then move it.
902 * Since uload is ~PPQMASK masked, no modifications are necessary if
903 * we end up in the same run queue.
905 if ((lp->lwp_priority ^ newpriority) & ~PPQMASK) {
909 * uload can change, calculate the adjustment to reduce
910 * edge cases since choosers scan the cpu topology without
913 if (lp->lwp_mpflags & LWP_MP_ULOAD) {
915 -((lp->lwp_priority & ~PPQMASK) & PRIMASK) +
916 ((newpriority & ~PPQMASK) & PRIMASK);
917 atomic_add_int(&dfly_pcpu[lp->lwp_qcpu].uload,
920 if (lp->lwp_mpflags & LWP_MP_ONRUNQ) {
921 dfly_remrunqueue_locked(rdd, lp);
922 lp->lwp_priority = newpriority;
923 lp->lwp_rqtype = newrqtype;
924 lp->lwp_rqindex = (newpriority & PRIMASK) / PPQ;
925 dfly_setrunqueue_locked(rdd, lp);
928 lp->lwp_priority = newpriority;
929 lp->lwp_rqtype = newrqtype;
930 lp->lwp_rqindex = (newpriority & PRIMASK) / PPQ;
935 * In the same PPQ, uload cannot change.
937 lp->lwp_priority = newpriority;
943 * Determine if we need to reschedule the target cpu. This only
944 * occurs if the LWP is already on a scheduler queue, which means
945 * that idle cpu notification has already occured. At most we
946 * need only issue a need_user_resched() on the appropriate cpu.
948 * The LWP may be owned by a CPU different from the current one,
949 * in which case dd->uschedcp may be modified without an MP lock
950 * or a spinlock held. The worst that happens is that the code
951 * below causes a spurious need_user_resched() on the target CPU
952 * and dd->pri to be wrong for a short period of time, both of
953 * which are harmless.
955 * If checkpri is 0 we are adjusting the priority of the current
956 * process, possibly higher (less desireable), so ignore the upri
957 * check which will fail in that case.
960 if ((dfly_rdyprocmask & CPUMASK(rcpu)) &&
962 (rdd->upri & ~PRIMASK) > (lp->lwp_priority & ~PRIMASK))) {
964 if (rcpu == mycpu->gd_cpuid) {
965 spin_unlock(&rdd->spin);
968 atomic_clear_cpumask(&dfly_rdyprocmask,
970 spin_unlock(&rdd->spin);
971 lwkt_send_ipiq(globaldata_find(rcpu),
972 dfly_need_user_resched_remote,
976 spin_unlock(&rdd->spin);
980 spin_unlock(&rdd->spin);
983 spin_unlock(&rdd->spin);
990 dfly_yield(struct lwp *lp)
993 /* FUTURE (or something similar) */
994 switch(lp->lwp_rqtype) {
995 case RTP_PRIO_NORMAL:
996 lp->lwp_estcpu = ESTCPULIM(lp->lwp_estcpu + ESTCPUINCR);
1002 need_user_resched();
1006 * Called from fork1() when a new child process is being created.
1008 * Give the child process an initial estcpu that is more batch then
1009 * its parent and dock the parent for the fork (but do not
1010 * reschedule the parent). This comprises the main part of our batch
1011 * detection heuristic for both parallel forking and sequential execs.
1013 * XXX lwp should be "spawning" instead of "forking"
1016 dfly_forking(struct lwp *plp, struct lwp *lp)
1019 * Put the child 4 queue slots (out of 32) higher than the parent
1020 * (less desireable than the parent).
1022 lp->lwp_estcpu = ESTCPULIM(plp->lwp_estcpu + ESTCPUPPQ * 4);
1025 * The batch status of children always starts out centerline
1026 * and will inch-up or inch-down as appropriate. It takes roughly
1027 * ~15 seconds of >50% cpu to hit the limit.
1029 lp->lwp_batch = BATCHMAX / 2;
1032 * Dock the parent a cost for the fork, protecting us from fork
1033 * bombs. If the parent is forking quickly make the child more
1036 plp->lwp_estcpu = ESTCPULIM(plp->lwp_estcpu + ESTCPUPPQ / 16);
1040 * Called when a lwp is being removed from this scheduler, typically
1041 * during lwp_exit().
1044 dfly_exiting(struct lwp *lp, struct proc *child_proc)
1046 dfly_pcpu_t dd = &dfly_pcpu[lp->lwp_qcpu];
1048 if (lp->lwp_mpflags & LWP_MP_ULOAD) {
1049 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ULOAD);
1050 atomic_add_int(&dd->uload,
1051 -((lp->lwp_priority & ~PPQMASK) & PRIMASK));
1056 dfly_uload_update(struct lwp *lp)
1058 dfly_pcpu_t dd = &dfly_pcpu[lp->lwp_qcpu];
1060 if (lp->lwp_thread->td_flags & TDF_RUNQ) {
1061 if ((lp->lwp_mpflags & LWP_MP_ULOAD) == 0) {
1062 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ULOAD);
1063 atomic_add_int(&dd->uload,
1064 ((lp->lwp_priority & ~PPQMASK) & PRIMASK));
1067 if (lp->lwp_mpflags & LWP_MP_ULOAD) {
1068 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ULOAD);
1069 atomic_add_int(&dd->uload,
1070 -((lp->lwp_priority & ~PPQMASK) & PRIMASK));
1076 * chooseproc() is called when a cpu needs a user process to LWKT schedule,
1077 * it selects a user process and returns it. If chklp is non-NULL and chklp
1078 * has a better or equal priority then the process that would otherwise be
1079 * chosen, NULL is returned.
1081 * Until we fix the RUNQ code the chklp test has to be strict or we may
1082 * bounce between processes trying to acquire the current process designation.
1084 * Must be called with dfly_spin exclusive held. The spinlock is
1085 * left intact through the entire routine.
1087 * if chklp is NULL this function will dive other cpu's queues looking
1088 * for work if the current queue is empty.
1092 dfly_chooseproc_locked(dfly_pcpu_t dd, struct lwp *chklp, int isremote)
1099 u_int32_t *which, *which2;
1104 /*usched_dfly_queue_checks*/
1106 rtqbits = dd->rtqueuebits;
1107 tsqbits = dd->queuebits;
1108 idqbits = dd->idqueuebits;
1111 pri = bsfl(rtqbits);
1112 q = &dd->rtqueues[pri];
1113 which = &dd->rtqueuebits;
1115 } else if (tsqbits) {
1116 pri = bsfl(tsqbits);
1117 q = &dd->queues[pri];
1118 which = &dd->queuebits;
1120 } else if (idqbits) {
1121 pri = bsfl(idqbits);
1122 q = &dd->idqueues[pri];
1123 which = &dd->idqueuebits;
1129 * Disallow remote->remote recursion
1134 * Pull a runnable thread from a remote run queue. We have
1135 * to adjust qcpu and uload manually because the lp we return
1136 * might be assigned directly to uschedcp (setrunqueue might
1139 xdd = dfly_choose_worst_queue(dd);
1140 if (xdd && xdd != dd && spin_trylock(&xdd->spin)) {
1141 lp = dfly_chooseproc_locked(xdd, NULL, 1);
1143 if (lp->lwp_mpflags & LWP_MP_ULOAD) {
1144 atomic_add_int(&xdd->uload,
1145 -((lp->lwp_priority & ~PPQMASK) &
1148 lp->lwp_qcpu = dd->cpuid;
1149 atomic_add_int(&dd->uload,
1150 ((lp->lwp_priority & ~PPQMASK) & PRIMASK));
1151 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ULOAD);
1153 spin_unlock(&xdd->spin);
1164 lp = TAILQ_FIRST(q);
1165 KASSERT(lp, ("chooseproc: no lwp on busy queue"));
1168 * If the passed lwp <chklp> is reasonably close to the selected
1169 * lwp <lp>, return NULL (indicating that <chklp> should be kept).
1171 * Note that we must error on the side of <chklp> to avoid bouncing
1172 * between threads in the acquire code.
1175 if (chklp->lwp_priority < lp->lwp_priority + PPQ)
1179 KTR_COND_LOG(usched_chooseproc,
1180 lp->lwp_proc->p_pid == usched_dfly_pid_debug,
1181 lp->lwp_proc->p_pid,
1182 lp->lwp_thread->td_gd->gd_cpuid,
1185 TAILQ_REMOVE(q, lp, lwp_procq);
1188 *which &= ~(1 << pri);
1189 KASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) != 0, ("not on runq6!"));
1190 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ);
1198 * USED TO PUSH RUNNABLE LWPS TO THE LEAST LOADED CPU.
1200 * Choose a cpu node to schedule lp on, hopefully nearby its current
1201 * node. The current node is passed in (dd) (though it can also be obtained
1202 * from lp->lwp_qcpu). The caller will dfly_setrunqueue() lp on the queue
1205 * When the topology is known choose a cpu whos group has, in aggregate,
1206 * has the lowest weighted load.
1210 dfly_choose_best_queue(dfly_pcpu_t dd, struct lwp *lp)
1224 * When the topology is unknown choose a random cpu that is hopefully
1227 if (dd->cpunode == NULL)
1228 return (dfly_choose_queue_simple(dd, lp));
1231 * When the topology is known choose a cpu whos group has, in
1232 * aggregate, has the lowest weighted load.
1234 cpup = root_cpu_node;
1236 level = cpu_topology_levels_number;
1240 * Degenerate case super-root
1242 if (cpup->child_node && cpup->child_no == 1) {
1243 cpup = cpup->child_node;
1251 if (cpup->child_node == NULL) {
1252 rdd = &dfly_pcpu[BSFCPUMASK(cpup->members)];
1257 lowest_load = 0x7FFFFFFF;
1259 for (n = 0; n < cpup->child_no; ++n) {
1261 * Accumulate load information for all cpus
1262 * which are members of this node.
1264 cpun = &cpup->child_node[n];
1265 mask = cpun->members & usched_global_cpumask &
1266 smp_active_mask & lp->lwp_cpumask;
1271 cpuid = BSFCPUMASK(mask);
1272 load += dfly_pcpu[cpuid].uload;
1273 mask &= ~CPUMASK(cpuid);
1277 * Give a slight advantage to nearby cpus.
1279 if (cpun->members & dd->cpumask)
1280 load -= PPQ * level;
1283 * Calculate the best load
1285 if (cpub == NULL || lowest_load > load ||
1286 (lowest_load == load &&
1287 (cpun->members & dd->cpumask))
1296 if (usched_dfly_chooser)
1297 kprintf("lp %02d->%02d %s\n",
1298 lp->lwp_qcpu, rdd->cpuid, lp->lwp_proc->p_comm);
1303 * USED TO PULL RUNNABLE LWPS FROM THE MOST LOADED CPU.
1305 * Choose the worst queue close to dd's cpu node with a non-empty runq.
1307 * This is used by the thread chooser when the current cpu's queues are
1308 * empty to steal a thread from another cpu's queue. We want to offload
1309 * the most heavily-loaded queue.
1313 dfly_choose_worst_queue(dfly_pcpu_t dd)
1328 * When the topology is unknown choose a random cpu that is hopefully
1331 if (dd->cpunode == NULL) {
1336 * When the topology is known choose a cpu whos group has, in
1337 * aggregate, has the lowest weighted load.
1339 cpup = root_cpu_node;
1341 level = cpu_topology_levels_number;
1344 * Degenerate case super-root
1346 if (cpup->child_node && cpup->child_no == 1) {
1347 cpup = cpup->child_node;
1355 if (cpup->child_node == NULL) {
1356 rdd = &dfly_pcpu[BSFCPUMASK(cpup->members)];
1363 for (n = 0; n < cpup->child_no; ++n) {
1365 * Accumulate load information for all cpus
1366 * which are members of this node.
1368 cpun = &cpup->child_node[n];
1369 mask = cpun->members & usched_global_cpumask &
1376 cpuid = BSFCPUMASK(mask);
1377 load += dfly_pcpu[cpuid].uload;
1378 if (dfly_pcpu[cpuid].uload)
1380 mask &= ~CPUMASK(cpuid);
1384 * Give a slight advantage to nearby cpus.
1386 if (cpun->members & dd->cpumask)
1387 load += PPQ * level;
1390 * The best candidate is the one with the worst
1391 * (highest) load. Prefer candiates that are
1392 * closer to our cpu.
1395 (cpub == NULL || highest_load < load ||
1396 (highest_load == load &&
1397 (cpun->members & dd->cpumask)))
1399 highest_load = load;
1411 dfly_choose_queue_simple(dfly_pcpu_t dd, struct lwp *lp)
1419 * Fallback to the original heuristic, select random cpu,
1420 * first checking cpus not currently running a user thread.
1422 cpuid = (dfly_scancpu & 0xFFFF) % ncpus;
1423 mask = ~dfly_curprocmask & dfly_rdyprocmask & lp->lwp_cpumask &
1424 smp_active_mask & usched_global_cpumask;
1427 tmpmask = ~(CPUMASK(cpuid) - 1);
1429 cpuid = BSFCPUMASK(mask & tmpmask);
1431 cpuid = BSFCPUMASK(mask);
1432 rdd = &dfly_pcpu[cpuid];
1434 if ((rdd->upri & ~PPQMASK) >= (lp->lwp_priority & ~PPQMASK))
1436 mask &= ~CPUMASK(cpuid);
1440 * Then cpus which might have a currently running lp
1442 cpuid = (dfly_scancpu & 0xFFFF) % ncpus;
1443 mask = dfly_curprocmask & dfly_rdyprocmask &
1444 lp->lwp_cpumask & smp_active_mask & usched_global_cpumask;
1447 tmpmask = ~(CPUMASK(cpuid) - 1);
1449 cpuid = BSFCPUMASK(mask & tmpmask);
1451 cpuid = BSFCPUMASK(mask);
1452 rdd = &dfly_pcpu[cpuid];
1454 if ((rdd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK))
1456 mask &= ~CPUMASK(cpuid);
1460 * If we cannot find a suitable cpu we reload from dfly_scancpu
1461 * and round-robin. Other cpus will pickup as they release their
1462 * current lwps or become ready.
1464 * Avoid a degenerate system lockup case if usched_global_cpumask
1465 * is set to 0 or otherwise does not cover lwp_cpumask.
1467 * We only kick the target helper thread in this case, we do not
1468 * set the user resched flag because
1470 cpuid = (dfly_scancpu & 0xFFFF) % ncpus;
1471 if ((CPUMASK(cpuid) & usched_global_cpumask) == 0)
1473 rdd = &dfly_pcpu[cpuid];
1480 dfly_need_user_resched_remote(void *dummy)
1482 globaldata_t gd = mycpu;
1483 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid];
1485 need_user_resched();
1487 /* Call wakeup_mycpu to avoid sending IPIs to other CPUs */
1488 wakeup_mycpu(&dd->helper_thread);
1494 * dfly_remrunqueue_locked() removes a given process from the run queue
1495 * that it is on, clearing the queue busy bit if it becomes empty.
1497 * Note that user process scheduler is different from the LWKT schedule.
1498 * The user process scheduler only manages user processes but it uses LWKT
1499 * underneath, and a user process operating in the kernel will often be
1500 * 'released' from our management.
1502 * uload is NOT adjusted here. It is only adjusted if the lwkt_thread goes
1503 * to sleep or the lwp is moved to a different runq.
1506 dfly_remrunqueue_locked(dfly_pcpu_t rdd, struct lwp *lp)
1512 KKASSERT(lp->lwp_mpflags & LWP_MP_ONRUNQ);
1513 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ);
1515 /*rdd->uload -= (lp->lwp_priority & ~PPQMASK) & PRIMASK;*/
1516 KKASSERT(rdd->runqcount >= 0);
1518 pri = lp->lwp_rqindex;
1519 switch(lp->lwp_rqtype) {
1520 case RTP_PRIO_NORMAL:
1521 q = &rdd->queues[pri];
1522 which = &rdd->queuebits;
1524 case RTP_PRIO_REALTIME:
1526 q = &rdd->rtqueues[pri];
1527 which = &rdd->rtqueuebits;
1530 q = &rdd->idqueues[pri];
1531 which = &rdd->idqueuebits;
1534 panic("remrunqueue: invalid rtprio type");
1537 TAILQ_REMOVE(q, lp, lwp_procq);
1538 if (TAILQ_EMPTY(q)) {
1539 KASSERT((*which & (1 << pri)) != 0,
1540 ("remrunqueue: remove from empty queue"));
1541 *which &= ~(1 << pri);
1546 * dfly_setrunqueue_locked()
1548 * Add a process whos rqtype and rqindex had previously been calculated
1549 * onto the appropriate run queue. Determine if the addition requires
1550 * a reschedule on a cpu and return the cpuid or -1.
1552 * NOTE: Lower priorities are better priorities.
1554 * NOTE ON ULOAD: This variable specifies the aggregate load on a cpu, the
1555 * sum of the rough lwp_priority for all running and runnable
1556 * processes. Lower priority processes (higher lwp_priority
1557 * values) actually DO count as more load, not less, because
1558 * these are the programs which require the most care with
1559 * regards to cpu selection.
1562 dfly_setrunqueue_locked(dfly_pcpu_t rdd, struct lwp *lp)
1568 if (lp->lwp_qcpu != rdd->cpuid) {
1569 if (lp->lwp_mpflags & LWP_MP_ULOAD) {
1570 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ULOAD);
1571 atomic_add_int(&dfly_pcpu[lp->lwp_qcpu].uload,
1572 -((lp->lwp_priority & ~PPQMASK) & PRIMASK));
1574 lp->lwp_qcpu = rdd->cpuid;
1577 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0);
1578 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ);
1580 if ((lp->lwp_mpflags & LWP_MP_ULOAD) == 0) {
1581 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ULOAD);
1582 atomic_add_int(&dfly_pcpu[lp->lwp_qcpu].uload,
1583 (lp->lwp_priority & ~PPQMASK) & PRIMASK);
1586 pri = lp->lwp_rqindex;
1588 switch(lp->lwp_rqtype) {
1589 case RTP_PRIO_NORMAL:
1590 q = &rdd->queues[pri];
1591 which = &rdd->queuebits;
1593 case RTP_PRIO_REALTIME:
1595 q = &rdd->rtqueues[pri];
1596 which = &rdd->rtqueuebits;
1599 q = &rdd->idqueues[pri];
1600 which = &rdd->idqueuebits;
1603 panic("remrunqueue: invalid rtprio type");
1608 * Add to the correct queue and set the appropriate bit. If no
1609 * lower priority (i.e. better) processes are in the queue then
1610 * we want a reschedule, calculate the best cpu for the job.
1612 * Always run reschedules on the LWPs original cpu.
1614 TAILQ_INSERT_TAIL(q, lp, lwp_procq);
1621 * For SMP systems a user scheduler helper thread is created for each
1622 * cpu and is used to allow one cpu to wakeup another for the purposes of
1623 * scheduling userland threads from setrunqueue().
1625 * UP systems do not need the helper since there is only one cpu.
1627 * We can't use the idle thread for this because we might block.
1628 * Additionally, doing things this way allows us to HLT idle cpus
1632 dfly_helper_thread(void *dummy)
1641 cpuid = gd->gd_cpuid; /* doesn't change */
1642 mask = gd->gd_cpumask; /* doesn't change */
1643 dd = &dfly_pcpu[cpuid];
1646 * Since we only want to be woken up only when no user processes
1647 * are scheduled on a cpu, run at an ultra low priority.
1649 lwkt_setpri_self(TDPRI_USER_SCHEDULER);
1651 tsleep(&dd->helper_thread, 0, "schslp", 0);
1655 * We use the LWKT deschedule-interlock trick to avoid racing
1656 * dfly_rdyprocmask. This means we cannot block through to the
1657 * manual lwkt_switch() call we make below.
1660 tsleep_interlock(&dd->helper_thread, 0);
1662 /*spin_lock(&dfly_spin);*/
1663 spin_lock(&dd->spin);
1665 atomic_set_cpumask(&dfly_rdyprocmask, mask);
1666 clear_user_resched(); /* This satisfied the reschedule request */
1667 dd->rrcount = 0; /* Reset the round-robin counter */
1669 if ((dfly_curprocmask & mask) == 0) {
1671 * No thread is currently scheduled.
1673 KKASSERT(dd->uschedcp == NULL);
1674 if ((nlp = dfly_chooseproc_locked(dd, NULL, 0)) != NULL) {
1675 KTR_COND_LOG(usched_sched_thread_no_process,
1676 nlp->lwp_proc->p_pid == usched_dfly_pid_debug,
1678 nlp->lwp_proc->p_pid,
1679 nlp->lwp_thread->td_gd->gd_cpuid);
1681 atomic_set_cpumask(&dfly_curprocmask, mask);
1682 dd->upri = nlp->lwp_priority;
1684 dd->rrcount = 0; /* reset round robin */
1685 spin_unlock(&dd->spin);
1686 /*spin_unlock(&dfly_spin);*/
1687 lwkt_acquire(nlp->lwp_thread);
1688 lwkt_schedule(nlp->lwp_thread);
1690 spin_unlock(&dd->spin);
1691 /*spin_unlock(&dfly_spin);*/
1693 } else if (dd->runqcount) {
1695 * Possibly find a better process to schedule.
1697 nlp = dfly_chooseproc_locked(dd, dd->uschedcp, 0);
1699 KTR_COND_LOG(usched_sched_thread_process,
1700 nlp->lwp_proc->p_pid == usched_dfly_pid_debug,
1702 nlp->lwp_proc->p_pid,
1703 nlp->lwp_thread->td_gd->gd_cpuid);
1705 dd->upri = nlp->lwp_priority;
1707 dd->rrcount = 0; /* reset round robin */
1708 spin_unlock(&dd->spin);
1709 /*spin_unlock(&dfly_spin);*/
1710 lwkt_acquire(nlp->lwp_thread);
1711 lwkt_schedule(nlp->lwp_thread);
1714 * Leave the thread on our run queue. Another
1715 * scheduler will try to pull it later.
1717 spin_unlock(&dd->spin);
1718 /*spin_unlock(&dfly_spin);*/
1722 * The runq is empty.
1724 spin_unlock(&dd->spin);
1725 /*spin_unlock(&dfly_spin);*/
1729 * We're descheduled unless someone scheduled us. Switch away.
1730 * Exiting the critical section will cause splz() to be called
1731 * for us if interrupts and such are pending.
1734 tsleep(&dd->helper_thread, PINTERLOCKED, "schslp", 0);
1738 /* sysctl stick_to_level parameter */
1740 sysctl_usched_dfly_stick_to_level(SYSCTL_HANDLER_ARGS)
1744 new_val = usched_dfly_stick_to_level;
1746 error = sysctl_handle_int(oidp, &new_val, 0, req);
1747 if (error != 0 || req->newptr == NULL)
1749 if (new_val > cpu_topology_levels_number - 1 || new_val < 0)
1751 usched_dfly_stick_to_level = new_val;
1756 * Setup our scheduler helpers. Note that curprocmask bit 0 has already
1757 * been cleared by rqinit() and we should not mess with it further.
1760 dfly_helper_thread_cpu_init(void)
1765 int smt_not_supported = 0;
1766 int cache_coherent_not_supported = 0;
1769 kprintf("Start scheduler helpers on cpus:\n");
1771 sysctl_ctx_init(&usched_dfly_sysctl_ctx);
1772 usched_dfly_sysctl_tree =
1773 SYSCTL_ADD_NODE(&usched_dfly_sysctl_ctx,
1774 SYSCTL_STATIC_CHILDREN(_kern), OID_AUTO,
1775 "usched_dfly", CTLFLAG_RD, 0, "");
1777 for (i = 0; i < ncpus; ++i) {
1778 dfly_pcpu_t dd = &dfly_pcpu[i];
1779 cpumask_t mask = CPUMASK(i);
1781 if ((mask & smp_active_mask) == 0)
1784 spin_init(&dd->spin);
1785 dd->cpunode = get_cpu_node_by_cpuid(i);
1787 dd->cpumask = CPUMASK(i);
1788 for (j = 0; j < NQS; j++) {
1789 TAILQ_INIT(&dd->queues[j]);
1790 TAILQ_INIT(&dd->rtqueues[j]);
1791 TAILQ_INIT(&dd->idqueues[j]);
1793 atomic_clear_cpumask(&dfly_curprocmask, 1);
1795 if (dd->cpunode == NULL) {
1796 smt_not_supported = 1;
1797 cache_coherent_not_supported = 1;
1799 kprintf ("\tcpu%d - WARNING: No CPU NODE "
1800 "found for cpu\n", i);
1802 switch (dd->cpunode->type) {
1805 kprintf ("\tcpu%d - HyperThreading "
1806 "available. Core siblings: ",
1810 smt_not_supported = 1;
1813 kprintf ("\tcpu%d - No HT available, "
1814 "multi-core/physical "
1815 "cpu. Physical siblings: ",
1819 smt_not_supported = 1;
1822 kprintf ("\tcpu%d - No HT available, "
1823 "single-core/physical cpu. "
1824 "Package Siblings: ",
1828 /* Let's go for safe defaults here */
1829 smt_not_supported = 1;
1830 cache_coherent_not_supported = 1;
1832 kprintf ("\tcpu%d - Unknown cpunode->"
1833 "type=%u. Siblings: ",
1835 (u_int)dd->cpunode->type);
1840 if (dd->cpunode->parent_node != NULL) {
1841 CPUSET_FOREACH(cpuid, dd->cpunode->parent_node->members)
1842 kprintf("cpu%d ", cpuid);
1845 kprintf(" no siblings\n");
1850 lwkt_create(dfly_helper_thread, NULL, NULL, &dd->helper_thread,
1851 0, i, "usched %d", i);
1854 * Allow user scheduling on the target cpu. cpu #0 has already
1855 * been enabled in rqinit().
1858 atomic_clear_cpumask(&dfly_curprocmask, mask);
1859 atomic_set_cpumask(&dfly_rdyprocmask, mask);
1860 dd->upri = PRIBASE_NULL;
1864 /* usched_dfly sysctl configurable parameters */
1866 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
1867 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1868 OID_AUTO, "rrinterval", CTLFLAG_RW,
1869 &usched_dfly_rrinterval, 0, "");
1870 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
1871 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1872 OID_AUTO, "decay", CTLFLAG_RW,
1873 &usched_dfly_decay, 0, "Extra decay when not running");
1874 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
1875 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1876 OID_AUTO, "batch_time", CTLFLAG_RW,
1877 &usched_dfly_batch_time, 0, "Min batch counter value");
1879 /* Add enable/disable option for SMT scheduling if supported */
1880 if (smt_not_supported) {
1881 usched_dfly_smt = 0;
1882 SYSCTL_ADD_STRING(&usched_dfly_sysctl_ctx,
1883 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1884 OID_AUTO, "smt", CTLFLAG_RD,
1885 "NOT SUPPORTED", 0, "SMT NOT SUPPORTED");
1887 usched_dfly_smt = 1;
1888 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
1889 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1890 OID_AUTO, "smt", CTLFLAG_RW,
1891 &usched_dfly_smt, 0, "Enable SMT scheduling");
1895 * Add enable/disable option for cache coherent scheduling
1898 if (cache_coherent_not_supported) {
1899 usched_dfly_cache_coherent = 0;
1900 SYSCTL_ADD_STRING(&usched_dfly_sysctl_ctx,
1901 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1902 OID_AUTO, "cache_coherent", CTLFLAG_RD,
1904 "Cache coherence NOT SUPPORTED");
1906 usched_dfly_cache_coherent = 1;
1907 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
1908 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1909 OID_AUTO, "cache_coherent", CTLFLAG_RW,
1910 &usched_dfly_cache_coherent, 0,
1911 "Enable/Disable cache coherent scheduling");
1913 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
1914 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1915 OID_AUTO, "upri_affinity", CTLFLAG_RW,
1916 &usched_dfly_upri_affinity, 1,
1917 "Number of PPQs in user priority check");
1919 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
1920 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1921 OID_AUTO, "queue_checks", CTLFLAG_RW,
1922 &usched_dfly_queue_checks, 5,
1923 "LWPs to check from a queue before giving up");
1925 SYSCTL_ADD_PROC(&usched_dfly_sysctl_ctx,
1926 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1927 OID_AUTO, "stick_to_level",
1928 CTLTYPE_INT | CTLFLAG_RW,
1929 NULL, sizeof usched_dfly_stick_to_level,
1930 sysctl_usched_dfly_stick_to_level, "I",
1931 "Stick a process to this level. See sysctl"
1932 "paremter hw.cpu_topology.level_description");
1935 SYSINIT(uschedtd, SI_BOOT2_USCHED, SI_ORDER_SECOND,
1936 dfly_helper_thread_cpu_init, NULL)
1938 #else /* No SMP options - just add the configurable parameters to sysctl */
1941 sched_sysctl_tree_init(void)
1943 sysctl_ctx_init(&usched_dfly_sysctl_ctx);
1944 usched_dfly_sysctl_tree =
1945 SYSCTL_ADD_NODE(&usched_dfly_sysctl_ctx,
1946 SYSCTL_STATIC_CHILDREN(_kern), OID_AUTO,
1947 "usched_dfly", CTLFLAG_RD, 0, "");
1949 /* usched_dfly sysctl configurable parameters */
1950 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
1951 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1952 OID_AUTO, "rrinterval", CTLFLAG_RW,
1953 &usched_dfly_rrinterval, 0, "");
1954 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
1955 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1956 OID_AUTO, "decay", CTLFLAG_RW,
1957 &usched_dfly_decay, 0, "Extra decay when not running");
1958 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx,
1959 SYSCTL_CHILDREN(usched_dfly_sysctl_tree),
1960 OID_AUTO, "batch_time", CTLFLAG_RW,
1961 &usched_dfly_batch_time, 0, "Min batch counter value");
1963 SYSINIT(uschedtd, SI_BOOT2_USCHED, SI_ORDER_SECOND,
1964 sched_sysctl_tree_init, NULL)