sched_ule.c revision 215240
1/*- 2 * Copyright (c) 2002-2007, Jeffrey Roberson <jeff@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27/* 28 * This file implements the ULE scheduler. ULE supports independent CPU 29 * run queues and fine grain locking. It has superior interactive 30 * performance under load even on uni-processor systems. 31 * 32 * etymology: 33 * ULE is the last three letters in schedule. It owes its name to a 34 * generic user created for a scheduling system by Paul Mikesell at 35 * Isilon Systems and a general lack of creativity on the part of the author. 36 */ 37 38#include <sys/cdefs.h> 39__FBSDID("$FreeBSD: head/sys/kern/sched_ule.c 215240 2010-11-13 11:54:04Z trasz $"); 40 41#include "opt_hwpmc_hooks.h" 42#include "opt_kdtrace.h" 43#include "opt_sched.h" 44 45#include <sys/param.h> 46#include <sys/systm.h> 47#include <sys/kdb.h> 48#include <sys/kernel.h> 49#include <sys/ktr.h> 50#include <sys/lock.h> 51#include <sys/mutex.h> 52#include <sys/proc.h> 53#include <sys/resource.h> 54#include <sys/resourcevar.h> 55#include <sys/sched.h> 56#include <sys/smp.h> 57#include <sys/sx.h> 58#include <sys/sysctl.h> 59#include <sys/sysproto.h> 60#include <sys/turnstile.h> 61#include <sys/umtx.h> 62#include <sys/vmmeter.h> 63#include <sys/cpuset.h> 64#include <sys/sbuf.h> 65 66#ifdef HWPMC_HOOKS 67#include <sys/pmckern.h> 68#endif 69 70#ifdef KDTRACE_HOOKS 71#include <sys/dtrace_bsd.h> 72int dtrace_vtime_active; 73dtrace_vtime_switch_func_t dtrace_vtime_switch_func; 74#endif 75 76#include <machine/cpu.h> 77#include <machine/smp.h> 78 79#if defined(__sparc64__) 80#error "This architecture is not currently compatible with ULE" 81#endif 82 83#define KTR_ULE 0 84 85#define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX))) 86#define TDQ_NAME_LEN (sizeof("sched lock ") + sizeof(__XSTRING(MAXCPU))) 87#define TDQ_LOADNAME_LEN (PCPU_NAME_LEN + sizeof(" load")) 88 89/* 90 * Thread scheduler specific section. All fields are protected 91 * by the thread lock. 92 */ 93struct td_sched { 94 struct runq *ts_runq; /* Run-queue we're queued on. */ 95 short ts_flags; /* TSF_* flags. */ 96 u_char ts_cpu; /* CPU that we have affinity for. */ 97 int ts_rltick; /* Real last tick, for affinity. */ 98 int ts_slice; /* Ticks of slice remaining. */ 99 u_int ts_slptime; /* Number of ticks we vol. slept */ 100 u_int ts_runtime; /* Number of ticks we were running */ 101 int ts_ltick; /* Last tick that we were running on */ 102 int ts_incrtick; /* Last tick that we incremented on */ 103 int ts_ftick; /* First tick that we were running on */ 104 int ts_ticks; /* Tick count */ 105#ifdef KTR 106 char ts_name[TS_NAME_LEN]; 107#endif 108}; 109/* flags kept in ts_flags */ 110#define TSF_BOUND 0x0001 /* Thread can not migrate. */ 111#define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */ 112 113static struct td_sched td_sched0; 114 115#define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0) 116#define THREAD_CAN_SCHED(td, cpu) \ 117 CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask) 118 119/* 120 * Cpu percentage computation macros and defines. 121 * 122 * SCHED_TICK_SECS: Number of seconds to average the cpu usage across. 123 * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across. 124 * SCHED_TICK_MAX: Maximum number of ticks before scaling back. 125 * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results. 126 * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count. 127 * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks. 128 */ 129#define SCHED_TICK_SECS 10 130#define SCHED_TICK_TARG (hz * SCHED_TICK_SECS) 131#define SCHED_TICK_MAX (SCHED_TICK_TARG + hz) 132#define SCHED_TICK_SHIFT 10 133#define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT) 134#define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz)) 135 136/* 137 * These macros determine priorities for non-interactive threads. They are 138 * assigned a priority based on their recent cpu utilization as expressed 139 * by the ratio of ticks to the tick total. NHALF priorities at the start 140 * and end of the MIN to MAX timeshare range are only reachable with negative 141 * or positive nice respectively. 142 * 143 * PRI_RANGE: Priority range for utilization dependent priorities. 144 * PRI_NRESV: Number of nice values. 145 * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total. 146 * PRI_NICE: Determines the part of the priority inherited from nice. 147 */ 148#define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN) 149#define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) 150#define SCHED_PRI_MIN (PRI_MIN_TIMESHARE + SCHED_PRI_NHALF) 151#define SCHED_PRI_MAX (PRI_MAX_TIMESHARE - SCHED_PRI_NHALF) 152#define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN) 153#define SCHED_PRI_TICKS(ts) \ 154 (SCHED_TICK_HZ((ts)) / \ 155 (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE)) 156#define SCHED_PRI_NICE(nice) (nice) 157 158/* 159 * These determine the interactivity of a process. Interactivity differs from 160 * cpu utilization in that it expresses the voluntary time slept vs time ran 161 * while cpu utilization includes all time not running. This more accurately 162 * models the intent of the thread. 163 * 164 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 165 * before throttling back. 166 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. 167 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 168 * INTERACT_THRESH: Threshold for placement on the current runq. 169 */ 170#define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT) 171#define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT) 172#define SCHED_INTERACT_MAX (100) 173#define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 174#define SCHED_INTERACT_THRESH (30) 175 176/* 177 * tickincr: Converts a stathz tick into a hz domain scaled by 178 * the shift factor. Without the shift the error rate 179 * due to rounding would be unacceptably high. 180 * realstathz: stathz is sometimes 0 and run off of hz. 181 * sched_slice: Runtime of each thread before rescheduling. 182 * preempt_thresh: Priority threshold for preemption and remote IPIs. 183 */ 184static int sched_interact = SCHED_INTERACT_THRESH; 185static int realstathz; 186static int tickincr; 187static int sched_slice = 1; 188#ifdef PREEMPTION 189#ifdef FULL_PREEMPTION 190static int preempt_thresh = PRI_MAX_IDLE; 191#else 192static int preempt_thresh = PRI_MIN_KERN; 193#endif 194#else 195static int preempt_thresh = 0; 196#endif 197static int static_boost = PRI_MIN_TIMESHARE; 198static int sched_idlespins = 10000; 199static int sched_idlespinthresh = 16; 200 201/* 202 * tdq - per processor runqs and statistics. All fields are protected by the 203 * tdq_lock. The load and lowpri may be accessed without to avoid excess 204 * locking in sched_pickcpu(); 205 */ 206struct tdq { 207 /* Ordered to improve efficiency of cpu_search() and switch(). */ 208 struct mtx tdq_lock; /* run queue lock. */ 209 struct cpu_group *tdq_cg; /* Pointer to cpu topology. */ 210 volatile int tdq_load; /* Aggregate load. */ 211 volatile int tdq_cpu_idle; /* cpu_idle() is active. */ 212 int tdq_sysload; /* For loadavg, !ITHD load. */ 213 int tdq_transferable; /* Transferable thread count. */ 214 short tdq_switchcnt; /* Switches this tick. */ 215 short tdq_oldswitchcnt; /* Switches last tick. */ 216 u_char tdq_lowpri; /* Lowest priority thread. */ 217 u_char tdq_ipipending; /* IPI pending. */ 218 u_char tdq_idx; /* Current insert index. */ 219 u_char tdq_ridx; /* Current removal index. */ 220 struct runq tdq_realtime; /* real-time run queue. */ 221 struct runq tdq_timeshare; /* timeshare run queue. */ 222 struct runq tdq_idle; /* Queue of IDLE threads. */ 223 char tdq_name[TDQ_NAME_LEN]; 224#ifdef KTR 225 char tdq_loadname[TDQ_LOADNAME_LEN]; 226#endif 227} __aligned(64); 228 229/* Idle thread states and config. */ 230#define TDQ_RUNNING 1 231#define TDQ_IDLE 2 232 233#ifdef SMP 234struct cpu_group *cpu_top; /* CPU topology */ 235 236#define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000)) 237#define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity)) 238 239/* 240 * Run-time tunables. 241 */ 242static int rebalance = 1; 243static int balance_interval = 128; /* Default set in sched_initticks(). */ 244static int affinity; 245static int steal_htt = 1; 246static int steal_idle = 1; 247static int steal_thresh = 2; 248 249/* 250 * One thread queue per processor. 251 */ 252static struct tdq tdq_cpu[MAXCPU]; 253static struct tdq *balance_tdq; 254static int balance_ticks; 255 256#define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)]) 257#define TDQ_CPU(x) (&tdq_cpu[(x)]) 258#define TDQ_ID(x) ((int)((x) - tdq_cpu)) 259#else /* !SMP */ 260static struct tdq tdq_cpu; 261 262#define TDQ_ID(x) (0) 263#define TDQ_SELF() (&tdq_cpu) 264#define TDQ_CPU(x) (&tdq_cpu) 265#endif 266 267#define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type)) 268#define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t))) 269#define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f)) 270#define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t))) 271#define TDQ_LOCKPTR(t) (&(t)->tdq_lock) 272 273static void sched_priority(struct thread *); 274static void sched_thread_priority(struct thread *, u_char); 275static int sched_interact_score(struct thread *); 276static void sched_interact_update(struct thread *); 277static void sched_interact_fork(struct thread *); 278static void sched_pctcpu_update(struct td_sched *); 279 280/* Operations on per processor queues */ 281static struct thread *tdq_choose(struct tdq *); 282static void tdq_setup(struct tdq *); 283static void tdq_load_add(struct tdq *, struct thread *); 284static void tdq_load_rem(struct tdq *, struct thread *); 285static __inline void tdq_runq_add(struct tdq *, struct thread *, int); 286static __inline void tdq_runq_rem(struct tdq *, struct thread *); 287static inline int sched_shouldpreempt(int, int, int); 288void tdq_print(int cpu); 289static void runq_print(struct runq *rq); 290static void tdq_add(struct tdq *, struct thread *, int); 291#ifdef SMP 292static int tdq_move(struct tdq *, struct tdq *); 293static int tdq_idled(struct tdq *); 294static void tdq_notify(struct tdq *, struct thread *); 295static struct thread *tdq_steal(struct tdq *, int); 296static struct thread *runq_steal(struct runq *, int); 297static int sched_pickcpu(struct thread *, int); 298static void sched_balance(void); 299static int sched_balance_pair(struct tdq *, struct tdq *); 300static inline struct tdq *sched_setcpu(struct thread *, int, int); 301static inline void thread_unblock_switch(struct thread *, struct mtx *); 302static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int); 303static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS); 304static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, 305 struct cpu_group *cg, int indent); 306#endif 307 308static void sched_setup(void *dummy); 309SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL); 310 311static void sched_initticks(void *dummy); 312SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, 313 NULL); 314 315/* 316 * Print the threads waiting on a run-queue. 317 */ 318static void 319runq_print(struct runq *rq) 320{ 321 struct rqhead *rqh; 322 struct thread *td; 323 int pri; 324 int j; 325 int i; 326 327 for (i = 0; i < RQB_LEN; i++) { 328 printf("\t\trunq bits %d 0x%zx\n", 329 i, rq->rq_status.rqb_bits[i]); 330 for (j = 0; j < RQB_BPW; j++) 331 if (rq->rq_status.rqb_bits[i] & (1ul << j)) { 332 pri = j + (i << RQB_L2BPW); 333 rqh = &rq->rq_queues[pri]; 334 TAILQ_FOREACH(td, rqh, td_runq) { 335 printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n", 336 td, td->td_name, td->td_priority, 337 td->td_rqindex, pri); 338 } 339 } 340 } 341} 342 343/* 344 * Print the status of a per-cpu thread queue. Should be a ddb show cmd. 345 */ 346void 347tdq_print(int cpu) 348{ 349 struct tdq *tdq; 350 351 tdq = TDQ_CPU(cpu); 352 353 printf("tdq %d:\n", TDQ_ID(tdq)); 354 printf("\tlock %p\n", TDQ_LOCKPTR(tdq)); 355 printf("\tLock name: %s\n", tdq->tdq_name); 356 printf("\tload: %d\n", tdq->tdq_load); 357 printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt); 358 printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt); 359 printf("\ttimeshare idx: %d\n", tdq->tdq_idx); 360 printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx); 361 printf("\tload transferable: %d\n", tdq->tdq_transferable); 362 printf("\tlowest priority: %d\n", tdq->tdq_lowpri); 363 printf("\trealtime runq:\n"); 364 runq_print(&tdq->tdq_realtime); 365 printf("\ttimeshare runq:\n"); 366 runq_print(&tdq->tdq_timeshare); 367 printf("\tidle runq:\n"); 368 runq_print(&tdq->tdq_idle); 369} 370 371static inline int 372sched_shouldpreempt(int pri, int cpri, int remote) 373{ 374 /* 375 * If the new priority is not better than the current priority there is 376 * nothing to do. 377 */ 378 if (pri >= cpri) 379 return (0); 380 /* 381 * Always preempt idle. 382 */ 383 if (cpri >= PRI_MIN_IDLE) 384 return (1); 385 /* 386 * If preemption is disabled don't preempt others. 387 */ 388 if (preempt_thresh == 0) 389 return (0); 390 /* 391 * Preempt if we exceed the threshold. 392 */ 393 if (pri <= preempt_thresh) 394 return (1); 395 /* 396 * If we're realtime or better and there is timeshare or worse running 397 * preempt only remote processors. 398 */ 399 if (remote && pri <= PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME) 400 return (1); 401 return (0); 402} 403 404#define TS_RQ_PPQ (((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS) 405/* 406 * Add a thread to the actual run-queue. Keeps transferable counts up to 407 * date with what is actually on the run-queue. Selects the correct 408 * queue position for timeshare threads. 409 */ 410static __inline void 411tdq_runq_add(struct tdq *tdq, struct thread *td, int flags) 412{ 413 struct td_sched *ts; 414 u_char pri; 415 416 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 417 THREAD_LOCK_ASSERT(td, MA_OWNED); 418 419 pri = td->td_priority; 420 ts = td->td_sched; 421 TD_SET_RUNQ(td); 422 if (THREAD_CAN_MIGRATE(td)) { 423 tdq->tdq_transferable++; 424 ts->ts_flags |= TSF_XFERABLE; 425 } 426 if (pri <= PRI_MAX_REALTIME) { 427 ts->ts_runq = &tdq->tdq_realtime; 428 } else if (pri <= PRI_MAX_TIMESHARE) { 429 ts->ts_runq = &tdq->tdq_timeshare; 430 KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE, 431 ("Invalid priority %d on timeshare runq", pri)); 432 /* 433 * This queue contains only priorities between MIN and MAX 434 * realtime. Use the whole queue to represent these values. 435 */ 436 if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) { 437 pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ; 438 pri = (pri + tdq->tdq_idx) % RQ_NQS; 439 /* 440 * This effectively shortens the queue by one so we 441 * can have a one slot difference between idx and 442 * ridx while we wait for threads to drain. 443 */ 444 if (tdq->tdq_ridx != tdq->tdq_idx && 445 pri == tdq->tdq_ridx) 446 pri = (unsigned char)(pri - 1) % RQ_NQS; 447 } else 448 pri = tdq->tdq_ridx; 449 runq_add_pri(ts->ts_runq, td, pri, flags); 450 return; 451 } else 452 ts->ts_runq = &tdq->tdq_idle; 453 runq_add(ts->ts_runq, td, flags); 454} 455 456/* 457 * Remove a thread from a run-queue. This typically happens when a thread 458 * is selected to run. Running threads are not on the queue and the 459 * transferable count does not reflect them. 460 */ 461static __inline void 462tdq_runq_rem(struct tdq *tdq, struct thread *td) 463{ 464 struct td_sched *ts; 465 466 ts = td->td_sched; 467 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 468 KASSERT(ts->ts_runq != NULL, 469 ("tdq_runq_remove: thread %p null ts_runq", td)); 470 if (ts->ts_flags & TSF_XFERABLE) { 471 tdq->tdq_transferable--; 472 ts->ts_flags &= ~TSF_XFERABLE; 473 } 474 if (ts->ts_runq == &tdq->tdq_timeshare) { 475 if (tdq->tdq_idx != tdq->tdq_ridx) 476 runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx); 477 else 478 runq_remove_idx(ts->ts_runq, td, NULL); 479 } else 480 runq_remove(ts->ts_runq, td); 481} 482 483/* 484 * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load 485 * for this thread to the referenced thread queue. 486 */ 487static void 488tdq_load_add(struct tdq *tdq, struct thread *td) 489{ 490 491 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 492 THREAD_LOCK_ASSERT(td, MA_OWNED); 493 494 tdq->tdq_load++; 495 if ((td->td_flags & TDF_NOLOAD) == 0) 496 tdq->tdq_sysload++; 497 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load); 498} 499 500/* 501 * Remove the load from a thread that is transitioning to a sleep state or 502 * exiting. 503 */ 504static void 505tdq_load_rem(struct tdq *tdq, struct thread *td) 506{ 507 508 THREAD_LOCK_ASSERT(td, MA_OWNED); 509 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 510 KASSERT(tdq->tdq_load != 0, 511 ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq))); 512 513 tdq->tdq_load--; 514 if ((td->td_flags & TDF_NOLOAD) == 0) 515 tdq->tdq_sysload--; 516 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load); 517} 518 519/* 520 * Set lowpri to its exact value by searching the run-queue and 521 * evaluating curthread. curthread may be passed as an optimization. 522 */ 523static void 524tdq_setlowpri(struct tdq *tdq, struct thread *ctd) 525{ 526 struct thread *td; 527 528 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 529 if (ctd == NULL) 530 ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread; 531 td = tdq_choose(tdq); 532 if (td == NULL || td->td_priority > ctd->td_priority) 533 tdq->tdq_lowpri = ctd->td_priority; 534 else 535 tdq->tdq_lowpri = td->td_priority; 536} 537 538#ifdef SMP 539struct cpu_search { 540 cpuset_t cs_mask; 541 u_int cs_load; 542 u_int cs_cpu; 543 int cs_limit; /* Min priority for low min load for high. */ 544}; 545 546#define CPU_SEARCH_LOWEST 0x1 547#define CPU_SEARCH_HIGHEST 0x2 548#define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST) 549 550#define CPUSET_FOREACH(cpu, mask) \ 551 for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++) \ 552 if ((mask) & 1 << (cpu)) 553 554static __inline int cpu_search(struct cpu_group *cg, struct cpu_search *low, 555 struct cpu_search *high, const int match); 556int cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low); 557int cpu_search_highest(struct cpu_group *cg, struct cpu_search *high); 558int cpu_search_both(struct cpu_group *cg, struct cpu_search *low, 559 struct cpu_search *high); 560 561/* 562 * This routine compares according to the match argument and should be 563 * reduced in actual instantiations via constant propagation and dead code 564 * elimination. 565 */ 566static __inline int 567cpu_compare(int cpu, struct cpu_search *low, struct cpu_search *high, 568 const int match) 569{ 570 struct tdq *tdq; 571 572 tdq = TDQ_CPU(cpu); 573 if (match & CPU_SEARCH_LOWEST) 574 if (CPU_ISSET(cpu, &low->cs_mask) && 575 tdq->tdq_load < low->cs_load && 576 tdq->tdq_lowpri > low->cs_limit) { 577 low->cs_cpu = cpu; 578 low->cs_load = tdq->tdq_load; 579 } 580 if (match & CPU_SEARCH_HIGHEST) 581 if (CPU_ISSET(cpu, &high->cs_mask) && 582 tdq->tdq_load >= high->cs_limit && 583 tdq->tdq_load > high->cs_load && 584 tdq->tdq_transferable) { 585 high->cs_cpu = cpu; 586 high->cs_load = tdq->tdq_load; 587 } 588 return (tdq->tdq_load); 589} 590 591/* 592 * Search the tree of cpu_groups for the lowest or highest loaded cpu 593 * according to the match argument. This routine actually compares the 594 * load on all paths through the tree and finds the least loaded cpu on 595 * the least loaded path, which may differ from the least loaded cpu in 596 * the system. This balances work among caches and busses. 597 * 598 * This inline is instantiated in three forms below using constants for the 599 * match argument. It is reduced to the minimum set for each case. It is 600 * also recursive to the depth of the tree. 601 */ 602static __inline int 603cpu_search(struct cpu_group *cg, struct cpu_search *low, 604 struct cpu_search *high, const int match) 605{ 606 int total; 607 608 total = 0; 609 if (cg->cg_children) { 610 struct cpu_search lgroup; 611 struct cpu_search hgroup; 612 struct cpu_group *child; 613 u_int lload; 614 int hload; 615 int load; 616 int i; 617 618 lload = -1; 619 hload = -1; 620 for (i = 0; i < cg->cg_children; i++) { 621 child = &cg->cg_child[i]; 622 if (match & CPU_SEARCH_LOWEST) { 623 lgroup = *low; 624 lgroup.cs_load = -1; 625 } 626 if (match & CPU_SEARCH_HIGHEST) { 627 hgroup = *high; 628 lgroup.cs_load = 0; 629 } 630 switch (match) { 631 case CPU_SEARCH_LOWEST: 632 load = cpu_search_lowest(child, &lgroup); 633 break; 634 case CPU_SEARCH_HIGHEST: 635 load = cpu_search_highest(child, &hgroup); 636 break; 637 case CPU_SEARCH_BOTH: 638 load = cpu_search_both(child, &lgroup, &hgroup); 639 break; 640 } 641 total += load; 642 if (match & CPU_SEARCH_LOWEST) 643 if (load < lload || low->cs_cpu == -1) { 644 *low = lgroup; 645 lload = load; 646 } 647 if (match & CPU_SEARCH_HIGHEST) 648 if (load > hload || high->cs_cpu == -1) { 649 hload = load; 650 *high = hgroup; 651 } 652 } 653 } else { 654 int cpu; 655 656 CPUSET_FOREACH(cpu, cg->cg_mask) 657 total += cpu_compare(cpu, low, high, match); 658 } 659 return (total); 660} 661 662/* 663 * cpu_search instantiations must pass constants to maintain the inline 664 * optimization. 665 */ 666int 667cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low) 668{ 669 return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST); 670} 671 672int 673cpu_search_highest(struct cpu_group *cg, struct cpu_search *high) 674{ 675 return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST); 676} 677 678int 679cpu_search_both(struct cpu_group *cg, struct cpu_search *low, 680 struct cpu_search *high) 681{ 682 return cpu_search(cg, low, high, CPU_SEARCH_BOTH); 683} 684 685/* 686 * Find the cpu with the least load via the least loaded path that has a 687 * lowpri greater than pri pri. A pri of -1 indicates any priority is 688 * acceptable. 689 */ 690static inline int 691sched_lowest(struct cpu_group *cg, cpuset_t mask, int pri) 692{ 693 struct cpu_search low; 694 695 low.cs_cpu = -1; 696 low.cs_load = -1; 697 low.cs_mask = mask; 698 low.cs_limit = pri; 699 cpu_search_lowest(cg, &low); 700 return low.cs_cpu; 701} 702 703/* 704 * Find the cpu with the highest load via the highest loaded path. 705 */ 706static inline int 707sched_highest(struct cpu_group *cg, cpuset_t mask, int minload) 708{ 709 struct cpu_search high; 710 711 high.cs_cpu = -1; 712 high.cs_load = 0; 713 high.cs_mask = mask; 714 high.cs_limit = minload; 715 cpu_search_highest(cg, &high); 716 return high.cs_cpu; 717} 718 719/* 720 * Simultaneously find the highest and lowest loaded cpu reachable via 721 * cg. 722 */ 723static inline void 724sched_both(struct cpu_group *cg, cpuset_t mask, int *lowcpu, int *highcpu) 725{ 726 struct cpu_search high; 727 struct cpu_search low; 728 729 low.cs_cpu = -1; 730 low.cs_limit = -1; 731 low.cs_load = -1; 732 low.cs_mask = mask; 733 high.cs_load = 0; 734 high.cs_cpu = -1; 735 high.cs_limit = -1; 736 high.cs_mask = mask; 737 cpu_search_both(cg, &low, &high); 738 *lowcpu = low.cs_cpu; 739 *highcpu = high.cs_cpu; 740 return; 741} 742 743static void 744sched_balance_group(struct cpu_group *cg) 745{ 746 cpuset_t mask; 747 int high; 748 int low; 749 int i; 750 751 CPU_FILL(&mask); 752 for (;;) { 753 sched_both(cg, mask, &low, &high); 754 if (low == high || low == -1 || high == -1) 755 break; 756 if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low))) 757 break; 758 /* 759 * If we failed to move any threads determine which cpu 760 * to kick out of the set and try again. 761 */ 762 if (TDQ_CPU(high)->tdq_transferable == 0) 763 CPU_CLR(high, &mask); 764 else 765 CPU_CLR(low, &mask); 766 } 767 768 for (i = 0; i < cg->cg_children; i++) 769 sched_balance_group(&cg->cg_child[i]); 770} 771 772static void 773sched_balance(void) 774{ 775 struct tdq *tdq; 776 777 /* 778 * Select a random time between .5 * balance_interval and 779 * 1.5 * balance_interval. 780 */ 781 balance_ticks = max(balance_interval / 2, 1); 782 balance_ticks += random() % balance_interval; 783 if (smp_started == 0 || rebalance == 0) 784 return; 785 tdq = TDQ_SELF(); 786 TDQ_UNLOCK(tdq); 787 sched_balance_group(cpu_top); 788 TDQ_LOCK(tdq); 789} 790 791/* 792 * Lock two thread queues using their address to maintain lock order. 793 */ 794static void 795tdq_lock_pair(struct tdq *one, struct tdq *two) 796{ 797 if (one < two) { 798 TDQ_LOCK(one); 799 TDQ_LOCK_FLAGS(two, MTX_DUPOK); 800 } else { 801 TDQ_LOCK(two); 802 TDQ_LOCK_FLAGS(one, MTX_DUPOK); 803 } 804} 805 806/* 807 * Unlock two thread queues. Order is not important here. 808 */ 809static void 810tdq_unlock_pair(struct tdq *one, struct tdq *two) 811{ 812 TDQ_UNLOCK(one); 813 TDQ_UNLOCK(two); 814} 815 816/* 817 * Transfer load between two imbalanced thread queues. 818 */ 819static int 820sched_balance_pair(struct tdq *high, struct tdq *low) 821{ 822 int transferable; 823 int high_load; 824 int low_load; 825 int moved; 826 int move; 827 int diff; 828 int i; 829 830 tdq_lock_pair(high, low); 831 transferable = high->tdq_transferable; 832 high_load = high->tdq_load; 833 low_load = low->tdq_load; 834 moved = 0; 835 /* 836 * Determine what the imbalance is and then adjust that to how many 837 * threads we actually have to give up (transferable). 838 */ 839 if (transferable != 0) { 840 diff = high_load - low_load; 841 move = diff / 2; 842 if (diff & 0x1) 843 move++; 844 move = min(move, transferable); 845 for (i = 0; i < move; i++) 846 moved += tdq_move(high, low); 847 /* 848 * IPI the target cpu to force it to reschedule with the new 849 * workload. 850 */ 851 ipi_cpu(TDQ_ID(low), IPI_PREEMPT); 852 } 853 tdq_unlock_pair(high, low); 854 return (moved); 855} 856 857/* 858 * Move a thread from one thread queue to another. 859 */ 860static int 861tdq_move(struct tdq *from, struct tdq *to) 862{ 863 struct td_sched *ts; 864 struct thread *td; 865 struct tdq *tdq; 866 int cpu; 867 868 TDQ_LOCK_ASSERT(from, MA_OWNED); 869 TDQ_LOCK_ASSERT(to, MA_OWNED); 870 871 tdq = from; 872 cpu = TDQ_ID(to); 873 td = tdq_steal(tdq, cpu); 874 if (td == NULL) 875 return (0); 876 ts = td->td_sched; 877 /* 878 * Although the run queue is locked the thread may be blocked. Lock 879 * it to clear this and acquire the run-queue lock. 880 */ 881 thread_lock(td); 882 /* Drop recursive lock on from acquired via thread_lock(). */ 883 TDQ_UNLOCK(from); 884 sched_rem(td); 885 ts->ts_cpu = cpu; 886 td->td_lock = TDQ_LOCKPTR(to); 887 tdq_add(to, td, SRQ_YIELDING); 888 return (1); 889} 890 891/* 892 * This tdq has idled. Try to steal a thread from another cpu and switch 893 * to it. 894 */ 895static int 896tdq_idled(struct tdq *tdq) 897{ 898 struct cpu_group *cg; 899 struct tdq *steal; 900 cpuset_t mask; 901 int thresh; 902 int cpu; 903 904 if (smp_started == 0 || steal_idle == 0) 905 return (1); 906 CPU_FILL(&mask); 907 CPU_CLR(PCPU_GET(cpuid), &mask); 908 /* We don't want to be preempted while we're iterating. */ 909 spinlock_enter(); 910 for (cg = tdq->tdq_cg; cg != NULL; ) { 911 if ((cg->cg_flags & CG_FLAG_THREAD) == 0) 912 thresh = steal_thresh; 913 else 914 thresh = 1; 915 cpu = sched_highest(cg, mask, thresh); 916 if (cpu == -1) { 917 cg = cg->cg_parent; 918 continue; 919 } 920 steal = TDQ_CPU(cpu); 921 CPU_CLR(cpu, &mask); 922 tdq_lock_pair(tdq, steal); 923 if (steal->tdq_load < thresh || steal->tdq_transferable == 0) { 924 tdq_unlock_pair(tdq, steal); 925 continue; 926 } 927 /* 928 * If a thread was added while interrupts were disabled don't 929 * steal one here. If we fail to acquire one due to affinity 930 * restrictions loop again with this cpu removed from the 931 * set. 932 */ 933 if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) { 934 tdq_unlock_pair(tdq, steal); 935 continue; 936 } 937 spinlock_exit(); 938 TDQ_UNLOCK(steal); 939 mi_switch(SW_VOL | SWT_IDLE, NULL); 940 thread_unlock(curthread); 941 942 return (0); 943 } 944 spinlock_exit(); 945 return (1); 946} 947 948/* 949 * Notify a remote cpu of new work. Sends an IPI if criteria are met. 950 */ 951static void 952tdq_notify(struct tdq *tdq, struct thread *td) 953{ 954 struct thread *ctd; 955 int pri; 956 int cpu; 957 958 if (tdq->tdq_ipipending) 959 return; 960 cpu = td->td_sched->ts_cpu; 961 pri = td->td_priority; 962 ctd = pcpu_find(cpu)->pc_curthread; 963 if (!sched_shouldpreempt(pri, ctd->td_priority, 1)) 964 return; 965 if (TD_IS_IDLETHREAD(ctd)) { 966 /* 967 * If the MD code has an idle wakeup routine try that before 968 * falling back to IPI. 969 */ 970 if (!tdq->tdq_cpu_idle || cpu_idle_wakeup(cpu)) 971 return; 972 } 973 tdq->tdq_ipipending = 1; 974 ipi_cpu(cpu, IPI_PREEMPT); 975} 976 977/* 978 * Steals load from a timeshare queue. Honors the rotating queue head 979 * index. 980 */ 981static struct thread * 982runq_steal_from(struct runq *rq, int cpu, u_char start) 983{ 984 struct rqbits *rqb; 985 struct rqhead *rqh; 986 struct thread *td; 987 int first; 988 int bit; 989 int pri; 990 int i; 991 992 rqb = &rq->rq_status; 993 bit = start & (RQB_BPW -1); 994 pri = 0; 995 first = 0; 996again: 997 for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) { 998 if (rqb->rqb_bits[i] == 0) 999 continue; 1000 if (bit != 0) { 1001 for (pri = bit; pri < RQB_BPW; pri++) 1002 if (rqb->rqb_bits[i] & (1ul << pri)) 1003 break; 1004 if (pri >= RQB_BPW) 1005 continue; 1006 } else 1007 pri = RQB_FFS(rqb->rqb_bits[i]); 1008 pri += (i << RQB_L2BPW); 1009 rqh = &rq->rq_queues[pri]; 1010 TAILQ_FOREACH(td, rqh, td_runq) { 1011 if (first && THREAD_CAN_MIGRATE(td) && 1012 THREAD_CAN_SCHED(td, cpu)) 1013 return (td); 1014 first = 1; 1015 } 1016 } 1017 if (start != 0) { 1018 start = 0; 1019 goto again; 1020 } 1021 1022 return (NULL); 1023} 1024 1025/* 1026 * Steals load from a standard linear queue. 1027 */ 1028static struct thread * 1029runq_steal(struct runq *rq, int cpu) 1030{ 1031 struct rqhead *rqh; 1032 struct rqbits *rqb; 1033 struct thread *td; 1034 int word; 1035 int bit; 1036 1037 rqb = &rq->rq_status; 1038 for (word = 0; word < RQB_LEN; word++) { 1039 if (rqb->rqb_bits[word] == 0) 1040 continue; 1041 for (bit = 0; bit < RQB_BPW; bit++) { 1042 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) 1043 continue; 1044 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; 1045 TAILQ_FOREACH(td, rqh, td_runq) 1046 if (THREAD_CAN_MIGRATE(td) && 1047 THREAD_CAN_SCHED(td, cpu)) 1048 return (td); 1049 } 1050 } 1051 return (NULL); 1052} 1053 1054/* 1055 * Attempt to steal a thread in priority order from a thread queue. 1056 */ 1057static struct thread * 1058tdq_steal(struct tdq *tdq, int cpu) 1059{ 1060 struct thread *td; 1061 1062 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1063 if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL) 1064 return (td); 1065 if ((td = runq_steal_from(&tdq->tdq_timeshare, 1066 cpu, tdq->tdq_ridx)) != NULL) 1067 return (td); 1068 return (runq_steal(&tdq->tdq_idle, cpu)); 1069} 1070 1071/* 1072 * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the 1073 * current lock and returns with the assigned queue locked. 1074 */ 1075static inline struct tdq * 1076sched_setcpu(struct thread *td, int cpu, int flags) 1077{ 1078 1079 struct tdq *tdq; 1080 1081 THREAD_LOCK_ASSERT(td, MA_OWNED); 1082 tdq = TDQ_CPU(cpu); 1083 td->td_sched->ts_cpu = cpu; 1084 /* 1085 * If the lock matches just return the queue. 1086 */ 1087 if (td->td_lock == TDQ_LOCKPTR(tdq)) 1088 return (tdq); 1089#ifdef notyet 1090 /* 1091 * If the thread isn't running its lockptr is a 1092 * turnstile or a sleepqueue. We can just lock_set without 1093 * blocking. 1094 */ 1095 if (TD_CAN_RUN(td)) { 1096 TDQ_LOCK(tdq); 1097 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 1098 return (tdq); 1099 } 1100#endif 1101 /* 1102 * The hard case, migration, we need to block the thread first to 1103 * prevent order reversals with other cpus locks. 1104 */ 1105 spinlock_enter(); 1106 thread_lock_block(td); 1107 TDQ_LOCK(tdq); 1108 thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); 1109 spinlock_exit(); 1110 return (tdq); 1111} 1112 1113SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding"); 1114SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity"); 1115SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity"); 1116SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load"); 1117SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu"); 1118SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration"); 1119 1120static int 1121sched_pickcpu(struct thread *td, int flags) 1122{ 1123 struct cpu_group *cg; 1124 struct td_sched *ts; 1125 struct tdq *tdq; 1126 cpuset_t mask; 1127 int self; 1128 int pri; 1129 int cpu; 1130 1131 self = PCPU_GET(cpuid); 1132 ts = td->td_sched; 1133 if (smp_started == 0) 1134 return (self); 1135 /* 1136 * Don't migrate a running thread from sched_switch(). 1137 */ 1138 if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td)) 1139 return (ts->ts_cpu); 1140 /* 1141 * Prefer to run interrupt threads on the processors that generate 1142 * the interrupt. 1143 */ 1144 if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) && 1145 curthread->td_intr_nesting_level && ts->ts_cpu != self) { 1146 SCHED_STAT_INC(pickcpu_intrbind); 1147 ts->ts_cpu = self; 1148 } 1149 /* 1150 * If the thread can run on the last cpu and the affinity has not 1151 * expired or it is idle run it there. 1152 */ 1153 pri = td->td_priority; 1154 tdq = TDQ_CPU(ts->ts_cpu); 1155 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) { 1156 if (tdq->tdq_lowpri > PRI_MIN_IDLE) { 1157 SCHED_STAT_INC(pickcpu_idle_affinity); 1158 return (ts->ts_cpu); 1159 } 1160 if (SCHED_AFFINITY(ts, CG_SHARE_L2) && tdq->tdq_lowpri > pri) { 1161 SCHED_STAT_INC(pickcpu_affinity); 1162 return (ts->ts_cpu); 1163 } 1164 } 1165 /* 1166 * Search for the highest level in the tree that still has affinity. 1167 */ 1168 cg = NULL; 1169 for (cg = tdq->tdq_cg; cg != NULL; cg = cg->cg_parent) 1170 if (SCHED_AFFINITY(ts, cg->cg_level)) 1171 break; 1172 cpu = -1; 1173 mask = td->td_cpuset->cs_mask; 1174 if (cg) 1175 cpu = sched_lowest(cg, mask, pri); 1176 if (cpu == -1) 1177 cpu = sched_lowest(cpu_top, mask, -1); 1178 /* 1179 * Compare the lowest loaded cpu to current cpu. 1180 */ 1181 if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri && 1182 TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE) { 1183 SCHED_STAT_INC(pickcpu_local); 1184 cpu = self; 1185 } else 1186 SCHED_STAT_INC(pickcpu_lowest); 1187 if (cpu != ts->ts_cpu) 1188 SCHED_STAT_INC(pickcpu_migration); 1189 KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu.")); 1190 return (cpu); 1191} 1192#endif 1193 1194/* 1195 * Pick the highest priority task we have and return it. 1196 */ 1197static struct thread * 1198tdq_choose(struct tdq *tdq) 1199{ 1200 struct thread *td; 1201 1202 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1203 td = runq_choose(&tdq->tdq_realtime); 1204 if (td != NULL) 1205 return (td); 1206 td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); 1207 if (td != NULL) { 1208 KASSERT(td->td_priority >= PRI_MIN_TIMESHARE, 1209 ("tdq_choose: Invalid priority on timeshare queue %d", 1210 td->td_priority)); 1211 return (td); 1212 } 1213 td = runq_choose(&tdq->tdq_idle); 1214 if (td != NULL) { 1215 KASSERT(td->td_priority >= PRI_MIN_IDLE, 1216 ("tdq_choose: Invalid priority on idle queue %d", 1217 td->td_priority)); 1218 return (td); 1219 } 1220 1221 return (NULL); 1222} 1223 1224/* 1225 * Initialize a thread queue. 1226 */ 1227static void 1228tdq_setup(struct tdq *tdq) 1229{ 1230 1231 if (bootverbose) 1232 printf("ULE: setup cpu %d\n", TDQ_ID(tdq)); 1233 runq_init(&tdq->tdq_realtime); 1234 runq_init(&tdq->tdq_timeshare); 1235 runq_init(&tdq->tdq_idle); 1236 snprintf(tdq->tdq_name, sizeof(tdq->tdq_name), 1237 "sched lock %d", (int)TDQ_ID(tdq)); 1238 mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock", 1239 MTX_SPIN | MTX_RECURSE); 1240#ifdef KTR 1241 snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname), 1242 "CPU %d load", (int)TDQ_ID(tdq)); 1243#endif 1244} 1245 1246#ifdef SMP 1247static void 1248sched_setup_smp(void) 1249{ 1250 struct tdq *tdq; 1251 int i; 1252 1253 cpu_top = smp_topo(); 1254 CPU_FOREACH(i) { 1255 tdq = TDQ_CPU(i); 1256 tdq_setup(tdq); 1257 tdq->tdq_cg = smp_topo_find(cpu_top, i); 1258 if (tdq->tdq_cg == NULL) 1259 panic("Can't find cpu group for %d\n", i); 1260 } 1261 balance_tdq = TDQ_SELF(); 1262 sched_balance(); 1263} 1264#endif 1265 1266/* 1267 * Setup the thread queues and initialize the topology based on MD 1268 * information. 1269 */ 1270static void 1271sched_setup(void *dummy) 1272{ 1273 struct tdq *tdq; 1274 1275 tdq = TDQ_SELF(); 1276#ifdef SMP 1277 sched_setup_smp(); 1278#else 1279 tdq_setup(tdq); 1280#endif 1281 /* 1282 * To avoid divide-by-zero, we set realstathz a dummy value 1283 * in case which sched_clock() called before sched_initticks(). 1284 */ 1285 realstathz = hz; 1286 sched_slice = (realstathz/10); /* ~100ms */ 1287 tickincr = 1 << SCHED_TICK_SHIFT; 1288 1289 /* Add thread0's load since it's running. */ 1290 TDQ_LOCK(tdq); 1291 thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1292 tdq_load_add(tdq, &thread0); 1293 tdq->tdq_lowpri = thread0.td_priority; 1294 TDQ_UNLOCK(tdq); 1295} 1296 1297/* 1298 * This routine determines the tickincr after stathz and hz are setup. 1299 */ 1300/* ARGSUSED */ 1301static void 1302sched_initticks(void *dummy) 1303{ 1304 int incr; 1305 1306 realstathz = stathz ? stathz : hz; 1307 sched_slice = (realstathz/10); /* ~100ms */ 1308 1309 /* 1310 * tickincr is shifted out by 10 to avoid rounding errors due to 1311 * hz not being evenly divisible by stathz on all platforms. 1312 */ 1313 incr = (hz << SCHED_TICK_SHIFT) / realstathz; 1314 /* 1315 * This does not work for values of stathz that are more than 1316 * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen. 1317 */ 1318 if (incr == 0) 1319 incr = 1; 1320 tickincr = incr; 1321#ifdef SMP 1322 /* 1323 * Set the default balance interval now that we know 1324 * what realstathz is. 1325 */ 1326 balance_interval = realstathz; 1327 /* 1328 * Set steal thresh to roughly log2(mp_ncpu) but no greater than 4. 1329 * This prevents excess thrashing on large machines and excess idle 1330 * on smaller machines. 1331 */ 1332 steal_thresh = min(fls(mp_ncpus) - 1, 3); 1333 affinity = SCHED_AFFINITY_DEFAULT; 1334#endif 1335} 1336 1337 1338/* 1339 * This is the core of the interactivity algorithm. Determines a score based 1340 * on past behavior. It is the ratio of sleep time to run time scaled to 1341 * a [0, 100] integer. This is the voluntary sleep time of a process, which 1342 * differs from the cpu usage because it does not account for time spent 1343 * waiting on a run-queue. Would be prettier if we had floating point. 1344 */ 1345static int 1346sched_interact_score(struct thread *td) 1347{ 1348 struct td_sched *ts; 1349 int div; 1350 1351 ts = td->td_sched; 1352 /* 1353 * The score is only needed if this is likely to be an interactive 1354 * task. Don't go through the expense of computing it if there's 1355 * no chance. 1356 */ 1357 if (sched_interact <= SCHED_INTERACT_HALF && 1358 ts->ts_runtime >= ts->ts_slptime) 1359 return (SCHED_INTERACT_HALF); 1360 1361 if (ts->ts_runtime > ts->ts_slptime) { 1362 div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF); 1363 return (SCHED_INTERACT_HALF + 1364 (SCHED_INTERACT_HALF - (ts->ts_slptime / div))); 1365 } 1366 if (ts->ts_slptime > ts->ts_runtime) { 1367 div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF); 1368 return (ts->ts_runtime / div); 1369 } 1370 /* runtime == slptime */ 1371 if (ts->ts_runtime) 1372 return (SCHED_INTERACT_HALF); 1373 1374 /* 1375 * This can happen if slptime and runtime are 0. 1376 */ 1377 return (0); 1378 1379} 1380 1381/* 1382 * Scale the scheduling priority according to the "interactivity" of this 1383 * process. 1384 */ 1385static void 1386sched_priority(struct thread *td) 1387{ 1388 int score; 1389 int pri; 1390 1391 if (td->td_pri_class != PRI_TIMESHARE) 1392 return; 1393 /* 1394 * If the score is interactive we place the thread in the realtime 1395 * queue with a priority that is less than kernel and interrupt 1396 * priorities. These threads are not subject to nice restrictions. 1397 * 1398 * Scores greater than this are placed on the normal timeshare queue 1399 * where the priority is partially decided by the most recent cpu 1400 * utilization and the rest is decided by nice value. 1401 * 1402 * The nice value of the process has a linear effect on the calculated 1403 * score. Negative nice values make it easier for a thread to be 1404 * considered interactive. 1405 */ 1406 score = imax(0, sched_interact_score(td) + td->td_proc->p_nice); 1407 if (score < sched_interact) { 1408 pri = PRI_MIN_REALTIME; 1409 pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME) / sched_interact) 1410 * score; 1411 KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME, 1412 ("sched_priority: invalid interactive priority %d score %d", 1413 pri, score)); 1414 } else { 1415 pri = SCHED_PRI_MIN; 1416 if (td->td_sched->ts_ticks) 1417 pri += SCHED_PRI_TICKS(td->td_sched); 1418 pri += SCHED_PRI_NICE(td->td_proc->p_nice); 1419 KASSERT(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE, 1420 ("sched_priority: invalid priority %d: nice %d, " 1421 "ticks %d ftick %d ltick %d tick pri %d", 1422 pri, td->td_proc->p_nice, td->td_sched->ts_ticks, 1423 td->td_sched->ts_ftick, td->td_sched->ts_ltick, 1424 SCHED_PRI_TICKS(td->td_sched))); 1425 } 1426 sched_user_prio(td, pri); 1427 1428 return; 1429} 1430 1431/* 1432 * This routine enforces a maximum limit on the amount of scheduling history 1433 * kept. It is called after either the slptime or runtime is adjusted. This 1434 * function is ugly due to integer math. 1435 */ 1436static void 1437sched_interact_update(struct thread *td) 1438{ 1439 struct td_sched *ts; 1440 u_int sum; 1441 1442 ts = td->td_sched; 1443 sum = ts->ts_runtime + ts->ts_slptime; 1444 if (sum < SCHED_SLP_RUN_MAX) 1445 return; 1446 /* 1447 * This only happens from two places: 1448 * 1) We have added an unusual amount of run time from fork_exit. 1449 * 2) We have added an unusual amount of sleep time from sched_sleep(). 1450 */ 1451 if (sum > SCHED_SLP_RUN_MAX * 2) { 1452 if (ts->ts_runtime > ts->ts_slptime) { 1453 ts->ts_runtime = SCHED_SLP_RUN_MAX; 1454 ts->ts_slptime = 1; 1455 } else { 1456 ts->ts_slptime = SCHED_SLP_RUN_MAX; 1457 ts->ts_runtime = 1; 1458 } 1459 return; 1460 } 1461 /* 1462 * If we have exceeded by more than 1/5th then the algorithm below 1463 * will not bring us back into range. Dividing by two here forces 1464 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] 1465 */ 1466 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { 1467 ts->ts_runtime /= 2; 1468 ts->ts_slptime /= 2; 1469 return; 1470 } 1471 ts->ts_runtime = (ts->ts_runtime / 5) * 4; 1472 ts->ts_slptime = (ts->ts_slptime / 5) * 4; 1473} 1474 1475/* 1476 * Scale back the interactivity history when a child thread is created. The 1477 * history is inherited from the parent but the thread may behave totally 1478 * differently. For example, a shell spawning a compiler process. We want 1479 * to learn that the compiler is behaving badly very quickly. 1480 */ 1481static void 1482sched_interact_fork(struct thread *td) 1483{ 1484 int ratio; 1485 int sum; 1486 1487 sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime; 1488 if (sum > SCHED_SLP_RUN_FORK) { 1489 ratio = sum / SCHED_SLP_RUN_FORK; 1490 td->td_sched->ts_runtime /= ratio; 1491 td->td_sched->ts_slptime /= ratio; 1492 } 1493} 1494 1495/* 1496 * Called from proc0_init() to setup the scheduler fields. 1497 */ 1498void 1499schedinit(void) 1500{ 1501 1502 /* 1503 * Set up the scheduler specific parts of proc0. 1504 */ 1505 proc0.p_sched = NULL; /* XXX */ 1506 thread0.td_sched = &td_sched0; 1507 td_sched0.ts_ltick = ticks; 1508 td_sched0.ts_ftick = ticks; 1509 td_sched0.ts_slice = sched_slice; 1510} 1511 1512/* 1513 * This is only somewhat accurate since given many processes of the same 1514 * priority they will switch when their slices run out, which will be 1515 * at most sched_slice stathz ticks. 1516 */ 1517int 1518sched_rr_interval(void) 1519{ 1520 1521 /* Convert sched_slice to hz */ 1522 return (hz/(realstathz/sched_slice)); 1523} 1524 1525/* 1526 * Update the percent cpu tracking information when it is requested or 1527 * the total history exceeds the maximum. We keep a sliding history of 1528 * tick counts that slowly decays. This is less precise than the 4BSD 1529 * mechanism since it happens with less regular and frequent events. 1530 */ 1531static void 1532sched_pctcpu_update(struct td_sched *ts) 1533{ 1534 1535 if (ts->ts_ticks == 0) 1536 return; 1537 if (ticks - (hz / 10) < ts->ts_ltick && 1538 SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX) 1539 return; 1540 /* 1541 * Adjust counters and watermark for pctcpu calc. 1542 */ 1543 if (ts->ts_ltick > ticks - SCHED_TICK_TARG) 1544 ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) * 1545 SCHED_TICK_TARG; 1546 else 1547 ts->ts_ticks = 0; 1548 ts->ts_ltick = ticks; 1549 ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG; 1550} 1551 1552/* 1553 * Adjust the priority of a thread. Move it to the appropriate run-queue 1554 * if necessary. This is the back-end for several priority related 1555 * functions. 1556 */ 1557static void 1558sched_thread_priority(struct thread *td, u_char prio) 1559{ 1560 struct td_sched *ts; 1561 struct tdq *tdq; 1562 int oldpri; 1563 1564 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio", 1565 "prio:%d", td->td_priority, "new prio:%d", prio, 1566 KTR_ATTR_LINKED, sched_tdname(curthread)); 1567 if (td != curthread && prio > td->td_priority) { 1568 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread), 1569 "lend prio", "prio:%d", td->td_priority, "new prio:%d", 1570 prio, KTR_ATTR_LINKED, sched_tdname(td)); 1571 } 1572 ts = td->td_sched; 1573 THREAD_LOCK_ASSERT(td, MA_OWNED); 1574 if (td->td_priority == prio) 1575 return; 1576 /* 1577 * If the priority has been elevated due to priority 1578 * propagation, we may have to move ourselves to a new 1579 * queue. This could be optimized to not re-add in some 1580 * cases. 1581 */ 1582 if (TD_ON_RUNQ(td) && prio < td->td_priority) { 1583 sched_rem(td); 1584 td->td_priority = prio; 1585 sched_add(td, SRQ_BORROWING); 1586 return; 1587 } 1588 /* 1589 * If the thread is currently running we may have to adjust the lowpri 1590 * information so other cpus are aware of our current priority. 1591 */ 1592 if (TD_IS_RUNNING(td)) { 1593 tdq = TDQ_CPU(ts->ts_cpu); 1594 oldpri = td->td_priority; 1595 td->td_priority = prio; 1596 if (prio < tdq->tdq_lowpri) 1597 tdq->tdq_lowpri = prio; 1598 else if (tdq->tdq_lowpri == oldpri) 1599 tdq_setlowpri(tdq, td); 1600 return; 1601 } 1602 td->td_priority = prio; 1603} 1604 1605/* 1606 * Update a thread's priority when it is lent another thread's 1607 * priority. 1608 */ 1609void 1610sched_lend_prio(struct thread *td, u_char prio) 1611{ 1612 1613 td->td_flags |= TDF_BORROWING; 1614 sched_thread_priority(td, prio); 1615} 1616 1617/* 1618 * Restore a thread's priority when priority propagation is 1619 * over. The prio argument is the minimum priority the thread 1620 * needs to have to satisfy other possible priority lending 1621 * requests. If the thread's regular priority is less 1622 * important than prio, the thread will keep a priority boost 1623 * of prio. 1624 */ 1625void 1626sched_unlend_prio(struct thread *td, u_char prio) 1627{ 1628 u_char base_pri; 1629 1630 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 1631 td->td_base_pri <= PRI_MAX_TIMESHARE) 1632 base_pri = td->td_user_pri; 1633 else 1634 base_pri = td->td_base_pri; 1635 if (prio >= base_pri) { 1636 td->td_flags &= ~TDF_BORROWING; 1637 sched_thread_priority(td, base_pri); 1638 } else 1639 sched_lend_prio(td, prio); 1640} 1641 1642/* 1643 * Standard entry for setting the priority to an absolute value. 1644 */ 1645void 1646sched_prio(struct thread *td, u_char prio) 1647{ 1648 u_char oldprio; 1649 1650 /* First, update the base priority. */ 1651 td->td_base_pri = prio; 1652 1653 /* 1654 * If the thread is borrowing another thread's priority, don't 1655 * ever lower the priority. 1656 */ 1657 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 1658 return; 1659 1660 /* Change the real priority. */ 1661 oldprio = td->td_priority; 1662 sched_thread_priority(td, prio); 1663 1664 /* 1665 * If the thread is on a turnstile, then let the turnstile update 1666 * its state. 1667 */ 1668 if (TD_ON_LOCK(td) && oldprio != prio) 1669 turnstile_adjust(td, oldprio); 1670} 1671 1672/* 1673 * Set the base user priority, does not effect current running priority. 1674 */ 1675void 1676sched_user_prio(struct thread *td, u_char prio) 1677{ 1678 1679 td->td_base_user_pri = prio; 1680 if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio) 1681 return; 1682 td->td_user_pri = prio; 1683} 1684 1685void 1686sched_lend_user_prio(struct thread *td, u_char prio) 1687{ 1688 1689 THREAD_LOCK_ASSERT(td, MA_OWNED); 1690 td->td_flags |= TDF_UBORROWING; 1691 td->td_user_pri = prio; 1692} 1693 1694void 1695sched_unlend_user_prio(struct thread *td, u_char prio) 1696{ 1697 u_char base_pri; 1698 1699 THREAD_LOCK_ASSERT(td, MA_OWNED); 1700 base_pri = td->td_base_user_pri; 1701 if (prio >= base_pri) { 1702 td->td_flags &= ~TDF_UBORROWING; 1703 sched_user_prio(td, base_pri); 1704 } else { 1705 sched_lend_user_prio(td, prio); 1706 } 1707} 1708 1709/* 1710 * Handle migration from sched_switch(). This happens only for 1711 * cpu binding. 1712 */ 1713static struct mtx * 1714sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) 1715{ 1716 struct tdq *tdn; 1717 1718 tdn = TDQ_CPU(td->td_sched->ts_cpu); 1719#ifdef SMP 1720 tdq_load_rem(tdq, td); 1721 /* 1722 * Do the lock dance required to avoid LOR. We grab an extra 1723 * spinlock nesting to prevent preemption while we're 1724 * not holding either run-queue lock. 1725 */ 1726 spinlock_enter(); 1727 thread_lock_block(td); /* This releases the lock on tdq. */ 1728 1729 /* 1730 * Acquire both run-queue locks before placing the thread on the new 1731 * run-queue to avoid deadlocks created by placing a thread with a 1732 * blocked lock on the run-queue of a remote processor. The deadlock 1733 * occurs when a third processor attempts to lock the two queues in 1734 * question while the target processor is spinning with its own 1735 * run-queue lock held while waiting for the blocked lock to clear. 1736 */ 1737 tdq_lock_pair(tdn, tdq); 1738 tdq_add(tdn, td, flags); 1739 tdq_notify(tdn, td); 1740 TDQ_UNLOCK(tdn); 1741 spinlock_exit(); 1742#endif 1743 return (TDQ_LOCKPTR(tdn)); 1744} 1745 1746/* 1747 * Variadic version of thread_lock_unblock() that does not assume td_lock 1748 * is blocked. 1749 */ 1750static inline void 1751thread_unblock_switch(struct thread *td, struct mtx *mtx) 1752{ 1753 atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock, 1754 (uintptr_t)mtx); 1755} 1756 1757/* 1758 * Switch threads. This function has to handle threads coming in while 1759 * blocked for some reason, running, or idle. It also must deal with 1760 * migrating a thread from one queue to another as running threads may 1761 * be assigned elsewhere via binding. 1762 */ 1763void 1764sched_switch(struct thread *td, struct thread *newtd, int flags) 1765{ 1766 struct tdq *tdq; 1767 struct td_sched *ts; 1768 struct mtx *mtx; 1769 int srqflag; 1770 int cpuid; 1771 1772 THREAD_LOCK_ASSERT(td, MA_OWNED); 1773 KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument")); 1774 1775 cpuid = PCPU_GET(cpuid); 1776 tdq = TDQ_CPU(cpuid); 1777 ts = td->td_sched; 1778 mtx = td->td_lock; 1779 ts->ts_rltick = ticks; 1780 td->td_lastcpu = td->td_oncpu; 1781 td->td_oncpu = NOCPU; 1782 td->td_flags &= ~TDF_NEEDRESCHED; 1783 td->td_owepreempt = 0; 1784 tdq->tdq_switchcnt++; 1785 /* 1786 * The lock pointer in an idle thread should never change. Reset it 1787 * to CAN_RUN as well. 1788 */ 1789 if (TD_IS_IDLETHREAD(td)) { 1790 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1791 TD_SET_CAN_RUN(td); 1792 } else if (TD_IS_RUNNING(td)) { 1793 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1794 srqflag = (flags & SW_PREEMPT) ? 1795 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1796 SRQ_OURSELF|SRQ_YIELDING; 1797#ifdef SMP 1798 if (THREAD_CAN_MIGRATE(td) && !THREAD_CAN_SCHED(td, ts->ts_cpu)) 1799 ts->ts_cpu = sched_pickcpu(td, 0); 1800#endif 1801 if (ts->ts_cpu == cpuid) 1802 tdq_runq_add(tdq, td, srqflag); 1803 else { 1804 KASSERT(THREAD_CAN_MIGRATE(td) || 1805 (ts->ts_flags & TSF_BOUND) != 0, 1806 ("Thread %p shouldn't migrate", td)); 1807 mtx = sched_switch_migrate(tdq, td, srqflag); 1808 } 1809 } else { 1810 /* This thread must be going to sleep. */ 1811 TDQ_LOCK(tdq); 1812 mtx = thread_lock_block(td); 1813 tdq_load_rem(tdq, td); 1814 } 1815 /* 1816 * We enter here with the thread blocked and assigned to the 1817 * appropriate cpu run-queue or sleep-queue and with the current 1818 * thread-queue locked. 1819 */ 1820 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 1821 newtd = choosethread(); 1822 /* 1823 * Call the MD code to switch contexts if necessary. 1824 */ 1825 if (td != newtd) { 1826#ifdef HWPMC_HOOKS 1827 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1828 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1829#endif 1830 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 1831 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 1832 1833#ifdef KDTRACE_HOOKS 1834 /* 1835 * If DTrace has set the active vtime enum to anything 1836 * other than INACTIVE (0), then it should have set the 1837 * function to call. 1838 */ 1839 if (dtrace_vtime_active) 1840 (*dtrace_vtime_switch_func)(newtd); 1841#endif 1842 1843 cpu_switch(td, newtd, mtx); 1844 /* 1845 * We may return from cpu_switch on a different cpu. However, 1846 * we always return with td_lock pointing to the current cpu's 1847 * run queue lock. 1848 */ 1849 cpuid = PCPU_GET(cpuid); 1850 tdq = TDQ_CPU(cpuid); 1851 lock_profile_obtain_lock_success( 1852 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 1853#ifdef HWPMC_HOOKS 1854 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1855 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1856#endif 1857 } else 1858 thread_unblock_switch(td, mtx); 1859 /* 1860 * Assert that all went well and return. 1861 */ 1862 TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED); 1863 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1864 td->td_oncpu = cpuid; 1865} 1866 1867/* 1868 * Adjust thread priorities as a result of a nice request. 1869 */ 1870void 1871sched_nice(struct proc *p, int nice) 1872{ 1873 struct thread *td; 1874 1875 PROC_LOCK_ASSERT(p, MA_OWNED); 1876 1877 p->p_nice = nice; 1878 FOREACH_THREAD_IN_PROC(p, td) { 1879 thread_lock(td); 1880 sched_priority(td); 1881 sched_prio(td, td->td_base_user_pri); 1882 thread_unlock(td); 1883 } 1884} 1885 1886/* 1887 * Record the sleep time for the interactivity scorer. 1888 */ 1889void 1890sched_sleep(struct thread *td, int prio) 1891{ 1892 1893 THREAD_LOCK_ASSERT(td, MA_OWNED); 1894 1895 td->td_slptick = ticks; 1896 if (TD_IS_SUSPENDED(td) || prio >= PSOCK) 1897 td->td_flags |= TDF_CANSWAP; 1898 if (static_boost == 1 && prio) 1899 sched_prio(td, prio); 1900 else if (static_boost && td->td_priority > static_boost) 1901 sched_prio(td, static_boost); 1902} 1903 1904/* 1905 * Schedule a thread to resume execution and record how long it voluntarily 1906 * slept. We also update the pctcpu, interactivity, and priority. 1907 */ 1908void 1909sched_wakeup(struct thread *td) 1910{ 1911 struct td_sched *ts; 1912 int slptick; 1913 1914 THREAD_LOCK_ASSERT(td, MA_OWNED); 1915 ts = td->td_sched; 1916 td->td_flags &= ~TDF_CANSWAP; 1917 /* 1918 * If we slept for more than a tick update our interactivity and 1919 * priority. 1920 */ 1921 slptick = td->td_slptick; 1922 td->td_slptick = 0; 1923 if (slptick && slptick != ticks) { 1924 u_int hzticks; 1925 1926 hzticks = (ticks - slptick) << SCHED_TICK_SHIFT; 1927 ts->ts_slptime += hzticks; 1928 sched_interact_update(td); 1929 sched_pctcpu_update(ts); 1930 } 1931 /* Reset the slice value after we sleep. */ 1932 ts->ts_slice = sched_slice; 1933 sched_add(td, SRQ_BORING); 1934} 1935 1936/* 1937 * Penalize the parent for creating a new child and initialize the child's 1938 * priority. 1939 */ 1940void 1941sched_fork(struct thread *td, struct thread *child) 1942{ 1943 THREAD_LOCK_ASSERT(td, MA_OWNED); 1944 sched_fork_thread(td, child); 1945 /* 1946 * Penalize the parent and child for forking. 1947 */ 1948 sched_interact_fork(child); 1949 sched_priority(child); 1950 td->td_sched->ts_runtime += tickincr; 1951 sched_interact_update(td); 1952 sched_priority(td); 1953} 1954 1955/* 1956 * Fork a new thread, may be within the same process. 1957 */ 1958void 1959sched_fork_thread(struct thread *td, struct thread *child) 1960{ 1961 struct td_sched *ts; 1962 struct td_sched *ts2; 1963 1964 THREAD_LOCK_ASSERT(td, MA_OWNED); 1965 /* 1966 * Initialize child. 1967 */ 1968 ts = td->td_sched; 1969 ts2 = child->td_sched; 1970 child->td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1971 child->td_cpuset = cpuset_ref(td->td_cpuset); 1972 ts2->ts_cpu = ts->ts_cpu; 1973 ts2->ts_flags = 0; 1974 /* 1975 * Grab our parents cpu estimation information and priority. 1976 */ 1977 ts2->ts_ticks = ts->ts_ticks; 1978 ts2->ts_ltick = ts->ts_ltick; 1979 ts2->ts_incrtick = ts->ts_incrtick; 1980 ts2->ts_ftick = ts->ts_ftick; 1981 child->td_user_pri = td->td_user_pri; 1982 child->td_base_user_pri = td->td_base_user_pri; 1983 /* 1984 * And update interactivity score. 1985 */ 1986 ts2->ts_slptime = ts->ts_slptime; 1987 ts2->ts_runtime = ts->ts_runtime; 1988 ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */ 1989#ifdef KTR 1990 bzero(ts2->ts_name, sizeof(ts2->ts_name)); 1991#endif 1992} 1993 1994/* 1995 * Adjust the priority class of a thread. 1996 */ 1997void 1998sched_class(struct thread *td, int class) 1999{ 2000 2001 THREAD_LOCK_ASSERT(td, MA_OWNED); 2002 if (td->td_pri_class == class) 2003 return; 2004 td->td_pri_class = class; 2005} 2006 2007/* 2008 * Return some of the child's priority and interactivity to the parent. 2009 */ 2010void 2011sched_exit(struct proc *p, struct thread *child) 2012{ 2013 struct thread *td; 2014 2015 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit", 2016 "prio:td", child->td_priority); 2017 PROC_LOCK_ASSERT(p, MA_OWNED); 2018 td = FIRST_THREAD_IN_PROC(p); 2019 sched_exit_thread(td, child); 2020} 2021 2022/* 2023 * Penalize another thread for the time spent on this one. This helps to 2024 * worsen the priority and interactivity of processes which schedule batch 2025 * jobs such as make. This has little effect on the make process itself but 2026 * causes new processes spawned by it to receive worse scores immediately. 2027 */ 2028void 2029sched_exit_thread(struct thread *td, struct thread *child) 2030{ 2031 2032 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit", 2033 "prio:td", child->td_priority); 2034 /* 2035 * Give the child's runtime to the parent without returning the 2036 * sleep time as a penalty to the parent. This causes shells that 2037 * launch expensive things to mark their children as expensive. 2038 */ 2039 thread_lock(td); 2040 td->td_sched->ts_runtime += child->td_sched->ts_runtime; 2041 sched_interact_update(td); 2042 sched_priority(td); 2043 thread_unlock(td); 2044} 2045 2046void 2047sched_preempt(struct thread *td) 2048{ 2049 struct tdq *tdq; 2050 2051 thread_lock(td); 2052 tdq = TDQ_SELF(); 2053 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2054 tdq->tdq_ipipending = 0; 2055 if (td->td_priority > tdq->tdq_lowpri) { 2056 int flags; 2057 2058 flags = SW_INVOL | SW_PREEMPT; 2059 if (td->td_critnest > 1) 2060 td->td_owepreempt = 1; 2061 else if (TD_IS_IDLETHREAD(td)) 2062 mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL); 2063 else 2064 mi_switch(flags | SWT_REMOTEPREEMPT, NULL); 2065 } 2066 thread_unlock(td); 2067} 2068 2069/* 2070 * Fix priorities on return to user-space. Priorities may be elevated due 2071 * to static priorities in msleep() or similar. 2072 */ 2073void 2074sched_userret(struct thread *td) 2075{ 2076 /* 2077 * XXX we cheat slightly on the locking here to avoid locking in 2078 * the usual case. Setting td_priority here is essentially an 2079 * incomplete workaround for not setting it properly elsewhere. 2080 * Now that some interrupt handlers are threads, not setting it 2081 * properly elsewhere can clobber it in the window between setting 2082 * it here and returning to user mode, so don't waste time setting 2083 * it perfectly here. 2084 */ 2085 KASSERT((td->td_flags & TDF_BORROWING) == 0, 2086 ("thread with borrowed priority returning to userland")); 2087 if (td->td_priority != td->td_user_pri) { 2088 thread_lock(td); 2089 td->td_priority = td->td_user_pri; 2090 td->td_base_pri = td->td_user_pri; 2091 tdq_setlowpri(TDQ_SELF(), td); 2092 thread_unlock(td); 2093 } 2094} 2095 2096/* 2097 * Handle a stathz tick. This is really only relevant for timeshare 2098 * threads. 2099 */ 2100void 2101sched_clock(struct thread *td) 2102{ 2103 struct tdq *tdq; 2104 struct td_sched *ts; 2105 2106 THREAD_LOCK_ASSERT(td, MA_OWNED); 2107 tdq = TDQ_SELF(); 2108#ifdef SMP 2109 /* 2110 * We run the long term load balancer infrequently on the first cpu. 2111 */ 2112 if (balance_tdq == tdq) { 2113 if (balance_ticks && --balance_ticks == 0) 2114 sched_balance(); 2115 } 2116#endif 2117 /* 2118 * Save the old switch count so we have a record of the last ticks 2119 * activity. Initialize the new switch count based on our load. 2120 * If there is some activity seed it to reflect that. 2121 */ 2122 tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt; 2123 tdq->tdq_switchcnt = tdq->tdq_load; 2124 /* 2125 * Advance the insert index once for each tick to ensure that all 2126 * threads get a chance to run. 2127 */ 2128 if (tdq->tdq_idx == tdq->tdq_ridx) { 2129 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; 2130 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) 2131 tdq->tdq_ridx = tdq->tdq_idx; 2132 } 2133 ts = td->td_sched; 2134 if (td->td_pri_class & PRI_FIFO_BIT) 2135 return; 2136 if (td->td_pri_class == PRI_TIMESHARE) { 2137 /* 2138 * We used a tick; charge it to the thread so 2139 * that we can compute our interactivity. 2140 */ 2141 td->td_sched->ts_runtime += tickincr; 2142 sched_interact_update(td); 2143 sched_priority(td); 2144 } 2145 /* 2146 * We used up one time slice. 2147 */ 2148 if (--ts->ts_slice > 0) 2149 return; 2150 /* 2151 * We're out of time, force a requeue at userret(). 2152 */ 2153 ts->ts_slice = sched_slice; 2154 td->td_flags |= TDF_NEEDRESCHED; 2155} 2156 2157/* 2158 * Called once per hz tick. Used for cpu utilization information. This 2159 * is easier than trying to scale based on stathz. 2160 */ 2161void 2162sched_tick(int cnt) 2163{ 2164 struct td_sched *ts; 2165 2166 ts = curthread->td_sched; 2167 /* 2168 * Ticks is updated asynchronously on a single cpu. Check here to 2169 * avoid incrementing ts_ticks multiple times in a single tick. 2170 */ 2171 if (ts->ts_incrtick == ticks) 2172 return; 2173 /* Adjust ticks for pctcpu */ 2174 ts->ts_ticks += cnt << SCHED_TICK_SHIFT; 2175 ts->ts_ltick = ticks; 2176 ts->ts_incrtick = ticks; 2177 /* 2178 * Update if we've exceeded our desired tick threshold by over one 2179 * second. 2180 */ 2181 if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick) 2182 sched_pctcpu_update(ts); 2183} 2184 2185/* 2186 * Return whether the current CPU has runnable tasks. Used for in-kernel 2187 * cooperative idle threads. 2188 */ 2189int 2190sched_runnable(void) 2191{ 2192 struct tdq *tdq; 2193 int load; 2194 2195 load = 1; 2196 2197 tdq = TDQ_SELF(); 2198 if ((curthread->td_flags & TDF_IDLETD) != 0) { 2199 if (tdq->tdq_load > 0) 2200 goto out; 2201 } else 2202 if (tdq->tdq_load - 1 > 0) 2203 goto out; 2204 load = 0; 2205out: 2206 return (load); 2207} 2208 2209/* 2210 * Choose the highest priority thread to run. The thread is removed from 2211 * the run-queue while running however the load remains. For SMP we set 2212 * the tdq in the global idle bitmask if it idles here. 2213 */ 2214struct thread * 2215sched_choose(void) 2216{ 2217 struct thread *td; 2218 struct tdq *tdq; 2219 2220 tdq = TDQ_SELF(); 2221 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2222 td = tdq_choose(tdq); 2223 if (td) { 2224 td->td_sched->ts_ltick = ticks; 2225 tdq_runq_rem(tdq, td); 2226 tdq->tdq_lowpri = td->td_priority; 2227 return (td); 2228 } 2229 tdq->tdq_lowpri = PRI_MAX_IDLE; 2230 return (PCPU_GET(idlethread)); 2231} 2232 2233/* 2234 * Set owepreempt if necessary. Preemption never happens directly in ULE, 2235 * we always request it once we exit a critical section. 2236 */ 2237static inline void 2238sched_setpreempt(struct thread *td) 2239{ 2240 struct thread *ctd; 2241 int cpri; 2242 int pri; 2243 2244 THREAD_LOCK_ASSERT(curthread, MA_OWNED); 2245 2246 ctd = curthread; 2247 pri = td->td_priority; 2248 cpri = ctd->td_priority; 2249 if (pri < cpri) 2250 ctd->td_flags |= TDF_NEEDRESCHED; 2251 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) 2252 return; 2253 if (!sched_shouldpreempt(pri, cpri, 0)) 2254 return; 2255 ctd->td_owepreempt = 1; 2256} 2257 2258/* 2259 * Add a thread to a thread queue. Select the appropriate runq and add the 2260 * thread to it. This is the internal function called when the tdq is 2261 * predetermined. 2262 */ 2263void 2264tdq_add(struct tdq *tdq, struct thread *td, int flags) 2265{ 2266 2267 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2268 KASSERT((td->td_inhibitors == 0), 2269 ("sched_add: trying to run inhibited thread")); 2270 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 2271 ("sched_add: bad thread state")); 2272 KASSERT(td->td_flags & TDF_INMEM, 2273 ("sched_add: thread swapped out")); 2274 2275 if (td->td_priority < tdq->tdq_lowpri) 2276 tdq->tdq_lowpri = td->td_priority; 2277 tdq_runq_add(tdq, td, flags); 2278 tdq_load_add(tdq, td); 2279} 2280 2281/* 2282 * Select the target thread queue and add a thread to it. Request 2283 * preemption or IPI a remote processor if required. 2284 */ 2285void 2286sched_add(struct thread *td, int flags) 2287{ 2288 struct tdq *tdq; 2289#ifdef SMP 2290 int cpu; 2291#endif 2292 2293 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", 2294 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 2295 sched_tdname(curthread)); 2296 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup", 2297 KTR_ATTR_LINKED, sched_tdname(td)); 2298 THREAD_LOCK_ASSERT(td, MA_OWNED); 2299 /* 2300 * Recalculate the priority before we select the target cpu or 2301 * run-queue. 2302 */ 2303 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 2304 sched_priority(td); 2305#ifdef SMP 2306 /* 2307 * Pick the destination cpu and if it isn't ours transfer to the 2308 * target cpu. 2309 */ 2310 cpu = sched_pickcpu(td, flags); 2311 tdq = sched_setcpu(td, cpu, flags); 2312 tdq_add(tdq, td, flags); 2313 if (cpu != PCPU_GET(cpuid)) { 2314 tdq_notify(tdq, td); 2315 return; 2316 } 2317#else 2318 tdq = TDQ_SELF(); 2319 TDQ_LOCK(tdq); 2320 /* 2321 * Now that the thread is moving to the run-queue, set the lock 2322 * to the scheduler's lock. 2323 */ 2324 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 2325 tdq_add(tdq, td, flags); 2326#endif 2327 if (!(flags & SRQ_YIELDING)) 2328 sched_setpreempt(td); 2329} 2330 2331/* 2332 * Remove a thread from a run-queue without running it. This is used 2333 * when we're stealing a thread from a remote queue. Otherwise all threads 2334 * exit by calling sched_exit_thread() and sched_throw() themselves. 2335 */ 2336void 2337sched_rem(struct thread *td) 2338{ 2339 struct tdq *tdq; 2340 2341 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem", 2342 "prio:%d", td->td_priority); 2343 tdq = TDQ_CPU(td->td_sched->ts_cpu); 2344 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2345 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2346 KASSERT(TD_ON_RUNQ(td), 2347 ("sched_rem: thread not on run queue")); 2348 tdq_runq_rem(tdq, td); 2349 tdq_load_rem(tdq, td); 2350 TD_SET_CAN_RUN(td); 2351 if (td->td_priority == tdq->tdq_lowpri) 2352 tdq_setlowpri(tdq, NULL); 2353} 2354 2355/* 2356 * Fetch cpu utilization information. Updates on demand. 2357 */ 2358fixpt_t 2359sched_pctcpu(struct thread *td) 2360{ 2361 fixpt_t pctcpu; 2362 struct td_sched *ts; 2363 2364 pctcpu = 0; 2365 ts = td->td_sched; 2366 if (ts == NULL) 2367 return (0); 2368 2369 THREAD_LOCK_ASSERT(td, MA_OWNED); 2370 if (ts->ts_ticks) { 2371 int rtick; 2372 2373 sched_pctcpu_update(ts); 2374 /* How many rtick per second ? */ 2375 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); 2376 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; 2377 } 2378 2379 return (pctcpu); 2380} 2381 2382/* 2383 * Enforce affinity settings for a thread. Called after adjustments to 2384 * cpumask. 2385 */ 2386void 2387sched_affinity(struct thread *td) 2388{ 2389#ifdef SMP 2390 struct td_sched *ts; 2391 2392 THREAD_LOCK_ASSERT(td, MA_OWNED); 2393 ts = td->td_sched; 2394 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) 2395 return; 2396 if (TD_ON_RUNQ(td)) { 2397 sched_rem(td); 2398 sched_add(td, SRQ_BORING); 2399 return; 2400 } 2401 if (!TD_IS_RUNNING(td)) 2402 return; 2403 /* 2404 * Force a switch before returning to userspace. If the 2405 * target thread is not running locally send an ipi to force 2406 * the issue. 2407 */ 2408 td->td_flags |= TDF_NEEDRESCHED; 2409 if (td != curthread) 2410 ipi_cpu(ts->ts_cpu, IPI_PREEMPT); 2411#endif 2412} 2413 2414/* 2415 * Bind a thread to a target cpu. 2416 */ 2417void 2418sched_bind(struct thread *td, int cpu) 2419{ 2420 struct td_sched *ts; 2421 2422 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 2423 KASSERT(td == curthread, ("sched_bind: can only bind curthread")); 2424 ts = td->td_sched; 2425 if (ts->ts_flags & TSF_BOUND) 2426 sched_unbind(td); 2427 KASSERT(THREAD_CAN_MIGRATE(td), ("%p must be migratable", td)); 2428 ts->ts_flags |= TSF_BOUND; 2429 sched_pin(); 2430 if (PCPU_GET(cpuid) == cpu) 2431 return; 2432 ts->ts_cpu = cpu; 2433 /* When we return from mi_switch we'll be on the correct cpu. */ 2434 mi_switch(SW_VOL, NULL); 2435} 2436 2437/* 2438 * Release a bound thread. 2439 */ 2440void 2441sched_unbind(struct thread *td) 2442{ 2443 struct td_sched *ts; 2444 2445 THREAD_LOCK_ASSERT(td, MA_OWNED); 2446 KASSERT(td == curthread, ("sched_unbind: can only bind curthread")); 2447 ts = td->td_sched; 2448 if ((ts->ts_flags & TSF_BOUND) == 0) 2449 return; 2450 ts->ts_flags &= ~TSF_BOUND; 2451 sched_unpin(); 2452} 2453 2454int 2455sched_is_bound(struct thread *td) 2456{ 2457 THREAD_LOCK_ASSERT(td, MA_OWNED); 2458 return (td->td_sched->ts_flags & TSF_BOUND); 2459} 2460 2461/* 2462 * Basic yield call. 2463 */ 2464void 2465sched_relinquish(struct thread *td) 2466{ 2467 thread_lock(td); 2468 mi_switch(SW_VOL | SWT_RELINQUISH, NULL); 2469 thread_unlock(td); 2470} 2471 2472/* 2473 * Return the total system load. 2474 */ 2475int 2476sched_load(void) 2477{ 2478#ifdef SMP 2479 int total; 2480 int i; 2481 2482 total = 0; 2483 CPU_FOREACH(i) 2484 total += TDQ_CPU(i)->tdq_sysload; 2485 return (total); 2486#else 2487 return (TDQ_SELF()->tdq_sysload); 2488#endif 2489} 2490 2491int 2492sched_sizeof_proc(void) 2493{ 2494 return (sizeof(struct proc)); 2495} 2496 2497int 2498sched_sizeof_thread(void) 2499{ 2500 return (sizeof(struct thread) + sizeof(struct td_sched)); 2501} 2502 2503#ifdef SMP 2504#define TDQ_IDLESPIN(tdq) \ 2505 ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0) 2506#else 2507#define TDQ_IDLESPIN(tdq) 1 2508#endif 2509 2510/* 2511 * The actual idle process. 2512 */ 2513void 2514sched_idletd(void *dummy) 2515{ 2516 struct thread *td; 2517 struct tdq *tdq; 2518 int switchcnt; 2519 int i; 2520 2521 mtx_assert(&Giant, MA_NOTOWNED); 2522 td = curthread; 2523 tdq = TDQ_SELF(); 2524 for (;;) { 2525#ifdef SMP 2526 if (tdq_idled(tdq) == 0) 2527 continue; 2528#endif 2529 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2530 /* 2531 * If we're switching very frequently, spin while checking 2532 * for load rather than entering a low power state that 2533 * may require an IPI. However, don't do any busy 2534 * loops while on SMT machines as this simply steals 2535 * cycles from cores doing useful work. 2536 */ 2537 if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) { 2538 for (i = 0; i < sched_idlespins; i++) { 2539 if (tdq->tdq_load) 2540 break; 2541 cpu_spinwait(); 2542 } 2543 } 2544 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2545 if (tdq->tdq_load == 0) { 2546 tdq->tdq_cpu_idle = 1; 2547 if (tdq->tdq_load == 0) { 2548 cpu_idle(switchcnt > sched_idlespinthresh * 4); 2549 tdq->tdq_switchcnt++; 2550 } 2551 tdq->tdq_cpu_idle = 0; 2552 } 2553 if (tdq->tdq_load) { 2554 thread_lock(td); 2555 mi_switch(SW_VOL | SWT_IDLE, NULL); 2556 thread_unlock(td); 2557 } 2558 } 2559} 2560 2561/* 2562 * A CPU is entering for the first time or a thread is exiting. 2563 */ 2564void 2565sched_throw(struct thread *td) 2566{ 2567 struct thread *newtd; 2568 struct tdq *tdq; 2569 2570 tdq = TDQ_SELF(); 2571 if (td == NULL) { 2572 /* Correct spinlock nesting and acquire the correct lock. */ 2573 TDQ_LOCK(tdq); 2574 spinlock_exit(); 2575 } else { 2576 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2577 tdq_load_rem(tdq, td); 2578 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 2579 } 2580 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 2581 newtd = choosethread(); 2582 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 2583 PCPU_SET(switchtime, cpu_ticks()); 2584 PCPU_SET(switchticks, ticks); 2585 cpu_throw(td, newtd); /* doesn't return */ 2586} 2587 2588/* 2589 * This is called from fork_exit(). Just acquire the correct locks and 2590 * let fork do the rest of the work. 2591 */ 2592void 2593sched_fork_exit(struct thread *td) 2594{ 2595 struct td_sched *ts; 2596 struct tdq *tdq; 2597 int cpuid; 2598 2599 /* 2600 * Finish setting up thread glue so that it begins execution in a 2601 * non-nested critical section with the scheduler lock held. 2602 */ 2603 cpuid = PCPU_GET(cpuid); 2604 tdq = TDQ_CPU(cpuid); 2605 ts = td->td_sched; 2606 if (TD_IS_IDLETHREAD(td)) 2607 td->td_lock = TDQ_LOCKPTR(tdq); 2608 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2609 td->td_oncpu = cpuid; 2610 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 2611 lock_profile_obtain_lock_success( 2612 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 2613} 2614 2615/* 2616 * Create on first use to catch odd startup conditons. 2617 */ 2618char * 2619sched_tdname(struct thread *td) 2620{ 2621#ifdef KTR 2622 struct td_sched *ts; 2623 2624 ts = td->td_sched; 2625 if (ts->ts_name[0] == '\0') 2626 snprintf(ts->ts_name, sizeof(ts->ts_name), 2627 "%s tid %d", td->td_name, td->td_tid); 2628 return (ts->ts_name); 2629#else 2630 return (td->td_name); 2631#endif 2632} 2633 2634#ifdef SMP 2635 2636/* 2637 * Build the CPU topology dump string. Is recursively called to collect 2638 * the topology tree. 2639 */ 2640static int 2641sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg, 2642 int indent) 2643{ 2644 int i, first; 2645 2646 sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent, 2647 "", 1 + indent / 2, cg->cg_level); 2648 sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"0x%x\">", indent, "", 2649 cg->cg_count, cg->cg_mask); 2650 first = TRUE; 2651 for (i = 0; i < MAXCPU; i++) { 2652 if ((cg->cg_mask & (1 << i)) != 0) { 2653 if (!first) 2654 sbuf_printf(sb, ", "); 2655 else 2656 first = FALSE; 2657 sbuf_printf(sb, "%d", i); 2658 } 2659 } 2660 sbuf_printf(sb, "</cpu>\n"); 2661 2662 if (cg->cg_flags != 0) { 2663 sbuf_printf(sb, "%*s <flags>", indent, ""); 2664 if ((cg->cg_flags & CG_FLAG_HTT) != 0) 2665 sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>"); 2666 if ((cg->cg_flags & CG_FLAG_THREAD) != 0) 2667 sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>"); 2668 if ((cg->cg_flags & CG_FLAG_SMT) != 0) 2669 sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>"); 2670 sbuf_printf(sb, "</flags>\n"); 2671 } 2672 2673 if (cg->cg_children > 0) { 2674 sbuf_printf(sb, "%*s <children>\n", indent, ""); 2675 for (i = 0; i < cg->cg_children; i++) 2676 sysctl_kern_sched_topology_spec_internal(sb, 2677 &cg->cg_child[i], indent+2); 2678 sbuf_printf(sb, "%*s </children>\n", indent, ""); 2679 } 2680 sbuf_printf(sb, "%*s</group>\n", indent, ""); 2681 return (0); 2682} 2683 2684/* 2685 * Sysctl handler for retrieving topology dump. It's a wrapper for 2686 * the recursive sysctl_kern_smp_topology_spec_internal(). 2687 */ 2688static int 2689sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS) 2690{ 2691 struct sbuf *topo; 2692 int err; 2693 2694 KASSERT(cpu_top != NULL, ("cpu_top isn't initialized")); 2695 2696 topo = sbuf_new(NULL, NULL, 500, SBUF_AUTOEXTEND); 2697 if (topo == NULL) 2698 return (ENOMEM); 2699 2700 sbuf_printf(topo, "<groups>\n"); 2701 err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1); 2702 sbuf_printf(topo, "</groups>\n"); 2703 2704 if (err == 0) { 2705 sbuf_finish(topo); 2706 err = SYSCTL_OUT(req, sbuf_data(topo), sbuf_len(topo)); 2707 } 2708 sbuf_delete(topo); 2709 return (err); 2710} 2711 2712#endif 2713 2714SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); 2715SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0, 2716 "Scheduler name"); 2717SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 2718 "Slice size for timeshare threads"); 2719SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, 2720 "Interactivity score threshold"); 2721SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh, 2722 0,"Min priority for preemption, lower priorities have greater precedence"); 2723SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 2724 0,"Controls whether static kernel priorities are assigned to sleeping threads."); 2725SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 2726 0,"Number of times idle will spin waiting for new work."); 2727SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW, &sched_idlespinthresh, 2728 0,"Threshold before we will permit idle spinning."); 2729#ifdef SMP 2730SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0, 2731 "Number of hz ticks to keep thread affinity for"); 2732SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, 2733 "Enables the long-term load balancer"); 2734SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW, 2735 &balance_interval, 0, 2736 "Average frequency in stathz ticks to run the long-term balancer"); 2737SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0, 2738 "Steals work from another hyper-threaded core on idle"); 2739SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0, 2740 "Attempts to steal work from other cores before idling"); 2741SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0, 2742 "Minimum load on remote cpu before we'll steal"); 2743 2744/* Retrieve SMP topology */ 2745SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING | 2746 CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A", 2747 "XML dump of detected CPU topology"); 2748 2749#endif 2750 2751/* ps compat. All cpu percentages from ULE are weighted. */ 2752static int ccpu = 0; 2753SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 2754