sched_ule.c revision 216313
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 216313 2010-12-09 02:42:02Z davidxu $"); 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_lend_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 if (prio < td->td_lend_user_pri) 1691 td->td_lend_user_pri = prio; 1692 if (prio < td->td_user_pri) 1693 td->td_user_pri = prio; 1694} 1695 1696void 1697sched_unlend_user_prio(struct thread *td, u_char prio) 1698{ 1699 u_char base_pri; 1700 1701 THREAD_LOCK_ASSERT(td, MA_OWNED); 1702 base_pri = td->td_base_user_pri; 1703 td->td_lend_user_pri = prio; 1704 if (prio > base_pri) 1705 td->td_user_pri = base_pri; 1706 else 1707 td->td_user_pri = prio; 1708} 1709 1710/* 1711 * Handle migration from sched_switch(). This happens only for 1712 * cpu binding. 1713 */ 1714static struct mtx * 1715sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) 1716{ 1717 struct tdq *tdn; 1718 1719 tdn = TDQ_CPU(td->td_sched->ts_cpu); 1720#ifdef SMP 1721 tdq_load_rem(tdq, td); 1722 /* 1723 * Do the lock dance required to avoid LOR. We grab an extra 1724 * spinlock nesting to prevent preemption while we're 1725 * not holding either run-queue lock. 1726 */ 1727 spinlock_enter(); 1728 thread_lock_block(td); /* This releases the lock on tdq. */ 1729 1730 /* 1731 * Acquire both run-queue locks before placing the thread on the new 1732 * run-queue to avoid deadlocks created by placing a thread with a 1733 * blocked lock on the run-queue of a remote processor. The deadlock 1734 * occurs when a third processor attempts to lock the two queues in 1735 * question while the target processor is spinning with its own 1736 * run-queue lock held while waiting for the blocked lock to clear. 1737 */ 1738 tdq_lock_pair(tdn, tdq); 1739 tdq_add(tdn, td, flags); 1740 tdq_notify(tdn, td); 1741 TDQ_UNLOCK(tdn); 1742 spinlock_exit(); 1743#endif 1744 return (TDQ_LOCKPTR(tdn)); 1745} 1746 1747/* 1748 * Variadic version of thread_lock_unblock() that does not assume td_lock 1749 * is blocked. 1750 */ 1751static inline void 1752thread_unblock_switch(struct thread *td, struct mtx *mtx) 1753{ 1754 atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock, 1755 (uintptr_t)mtx); 1756} 1757 1758/* 1759 * Switch threads. This function has to handle threads coming in while 1760 * blocked for some reason, running, or idle. It also must deal with 1761 * migrating a thread from one queue to another as running threads may 1762 * be assigned elsewhere via binding. 1763 */ 1764void 1765sched_switch(struct thread *td, struct thread *newtd, int flags) 1766{ 1767 struct tdq *tdq; 1768 struct td_sched *ts; 1769 struct mtx *mtx; 1770 int srqflag; 1771 int cpuid; 1772 1773 THREAD_LOCK_ASSERT(td, MA_OWNED); 1774 KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument")); 1775 1776 cpuid = PCPU_GET(cpuid); 1777 tdq = TDQ_CPU(cpuid); 1778 ts = td->td_sched; 1779 mtx = td->td_lock; 1780 ts->ts_rltick = ticks; 1781 td->td_lastcpu = td->td_oncpu; 1782 td->td_oncpu = NOCPU; 1783 td->td_flags &= ~TDF_NEEDRESCHED; 1784 td->td_owepreempt = 0; 1785 tdq->tdq_switchcnt++; 1786 /* 1787 * The lock pointer in an idle thread should never change. Reset it 1788 * to CAN_RUN as well. 1789 */ 1790 if (TD_IS_IDLETHREAD(td)) { 1791 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1792 TD_SET_CAN_RUN(td); 1793 } else if (TD_IS_RUNNING(td)) { 1794 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1795 srqflag = (flags & SW_PREEMPT) ? 1796 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1797 SRQ_OURSELF|SRQ_YIELDING; 1798#ifdef SMP 1799 if (THREAD_CAN_MIGRATE(td) && !THREAD_CAN_SCHED(td, ts->ts_cpu)) 1800 ts->ts_cpu = sched_pickcpu(td, 0); 1801#endif 1802 if (ts->ts_cpu == cpuid) 1803 tdq_runq_add(tdq, td, srqflag); 1804 else { 1805 KASSERT(THREAD_CAN_MIGRATE(td) || 1806 (ts->ts_flags & TSF_BOUND) != 0, 1807 ("Thread %p shouldn't migrate", td)); 1808 mtx = sched_switch_migrate(tdq, td, srqflag); 1809 } 1810 } else { 1811 /* This thread must be going to sleep. */ 1812 TDQ_LOCK(tdq); 1813 mtx = thread_lock_block(td); 1814 tdq_load_rem(tdq, td); 1815 } 1816 /* 1817 * We enter here with the thread blocked and assigned to the 1818 * appropriate cpu run-queue or sleep-queue and with the current 1819 * thread-queue locked. 1820 */ 1821 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 1822 newtd = choosethread(); 1823 /* 1824 * Call the MD code to switch contexts if necessary. 1825 */ 1826 if (td != newtd) { 1827#ifdef HWPMC_HOOKS 1828 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1829 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1830#endif 1831 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 1832 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 1833 1834#ifdef KDTRACE_HOOKS 1835 /* 1836 * If DTrace has set the active vtime enum to anything 1837 * other than INACTIVE (0), then it should have set the 1838 * function to call. 1839 */ 1840 if (dtrace_vtime_active) 1841 (*dtrace_vtime_switch_func)(newtd); 1842#endif 1843 1844 cpu_switch(td, newtd, mtx); 1845 /* 1846 * We may return from cpu_switch on a different cpu. However, 1847 * we always return with td_lock pointing to the current cpu's 1848 * run queue lock. 1849 */ 1850 cpuid = PCPU_GET(cpuid); 1851 tdq = TDQ_CPU(cpuid); 1852 lock_profile_obtain_lock_success( 1853 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 1854#ifdef HWPMC_HOOKS 1855 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1856 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1857#endif 1858 } else 1859 thread_unblock_switch(td, mtx); 1860 /* 1861 * Assert that all went well and return. 1862 */ 1863 TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED); 1864 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1865 td->td_oncpu = cpuid; 1866} 1867 1868/* 1869 * Adjust thread priorities as a result of a nice request. 1870 */ 1871void 1872sched_nice(struct proc *p, int nice) 1873{ 1874 struct thread *td; 1875 1876 PROC_LOCK_ASSERT(p, MA_OWNED); 1877 1878 p->p_nice = nice; 1879 FOREACH_THREAD_IN_PROC(p, td) { 1880 thread_lock(td); 1881 sched_priority(td); 1882 sched_prio(td, td->td_base_user_pri); 1883 thread_unlock(td); 1884 } 1885} 1886 1887/* 1888 * Record the sleep time for the interactivity scorer. 1889 */ 1890void 1891sched_sleep(struct thread *td, int prio) 1892{ 1893 1894 THREAD_LOCK_ASSERT(td, MA_OWNED); 1895 1896 td->td_slptick = ticks; 1897 if (TD_IS_SUSPENDED(td) || prio >= PSOCK) 1898 td->td_flags |= TDF_CANSWAP; 1899 if (static_boost == 1 && prio) 1900 sched_prio(td, prio); 1901 else if (static_boost && td->td_priority > static_boost) 1902 sched_prio(td, static_boost); 1903} 1904 1905/* 1906 * Schedule a thread to resume execution and record how long it voluntarily 1907 * slept. We also update the pctcpu, interactivity, and priority. 1908 */ 1909void 1910sched_wakeup(struct thread *td) 1911{ 1912 struct td_sched *ts; 1913 int slptick; 1914 1915 THREAD_LOCK_ASSERT(td, MA_OWNED); 1916 ts = td->td_sched; 1917 td->td_flags &= ~TDF_CANSWAP; 1918 /* 1919 * If we slept for more than a tick update our interactivity and 1920 * priority. 1921 */ 1922 slptick = td->td_slptick; 1923 td->td_slptick = 0; 1924 if (slptick && slptick != ticks) { 1925 u_int hzticks; 1926 1927 hzticks = (ticks - slptick) << SCHED_TICK_SHIFT; 1928 ts->ts_slptime += hzticks; 1929 sched_interact_update(td); 1930 sched_pctcpu_update(ts); 1931 } 1932 /* Reset the slice value after we sleep. */ 1933 ts->ts_slice = sched_slice; 1934 sched_add(td, SRQ_BORING); 1935} 1936 1937/* 1938 * Penalize the parent for creating a new child and initialize the child's 1939 * priority. 1940 */ 1941void 1942sched_fork(struct thread *td, struct thread *child) 1943{ 1944 THREAD_LOCK_ASSERT(td, MA_OWNED); 1945 sched_fork_thread(td, child); 1946 /* 1947 * Penalize the parent and child for forking. 1948 */ 1949 sched_interact_fork(child); 1950 sched_priority(child); 1951 td->td_sched->ts_runtime += tickincr; 1952 sched_interact_update(td); 1953 sched_priority(td); 1954} 1955 1956/* 1957 * Fork a new thread, may be within the same process. 1958 */ 1959void 1960sched_fork_thread(struct thread *td, struct thread *child) 1961{ 1962 struct td_sched *ts; 1963 struct td_sched *ts2; 1964 1965 THREAD_LOCK_ASSERT(td, MA_OWNED); 1966 /* 1967 * Initialize child. 1968 */ 1969 ts = td->td_sched; 1970 ts2 = child->td_sched; 1971 child->td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1972 child->td_cpuset = cpuset_ref(td->td_cpuset); 1973 ts2->ts_cpu = ts->ts_cpu; 1974 ts2->ts_flags = 0; 1975 /* 1976 * Grab our parents cpu estimation information and priority. 1977 */ 1978 ts2->ts_ticks = ts->ts_ticks; 1979 ts2->ts_ltick = ts->ts_ltick; 1980 ts2->ts_incrtick = ts->ts_incrtick; 1981 ts2->ts_ftick = ts->ts_ftick; 1982 child->td_user_pri = td->td_user_pri; 1983 child->td_base_user_pri = td->td_base_user_pri; 1984 /* 1985 * And update interactivity score. 1986 */ 1987 ts2->ts_slptime = ts->ts_slptime; 1988 ts2->ts_runtime = ts->ts_runtime; 1989 ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */ 1990#ifdef KTR 1991 bzero(ts2->ts_name, sizeof(ts2->ts_name)); 1992#endif 1993} 1994 1995/* 1996 * Adjust the priority class of a thread. 1997 */ 1998void 1999sched_class(struct thread *td, int class) 2000{ 2001 2002 THREAD_LOCK_ASSERT(td, MA_OWNED); 2003 if (td->td_pri_class == class) 2004 return; 2005 td->td_pri_class = class; 2006} 2007 2008/* 2009 * Return some of the child's priority and interactivity to the parent. 2010 */ 2011void 2012sched_exit(struct proc *p, struct thread *child) 2013{ 2014 struct thread *td; 2015 2016 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit", 2017 "prio:td", child->td_priority); 2018 PROC_LOCK_ASSERT(p, MA_OWNED); 2019 td = FIRST_THREAD_IN_PROC(p); 2020 sched_exit_thread(td, child); 2021} 2022 2023/* 2024 * Penalize another thread for the time spent on this one. This helps to 2025 * worsen the priority and interactivity of processes which schedule batch 2026 * jobs such as make. This has little effect on the make process itself but 2027 * causes new processes spawned by it to receive worse scores immediately. 2028 */ 2029void 2030sched_exit_thread(struct thread *td, struct thread *child) 2031{ 2032 2033 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit", 2034 "prio:td", child->td_priority); 2035 /* 2036 * Give the child's runtime to the parent without returning the 2037 * sleep time as a penalty to the parent. This causes shells that 2038 * launch expensive things to mark their children as expensive. 2039 */ 2040 thread_lock(td); 2041 td->td_sched->ts_runtime += child->td_sched->ts_runtime; 2042 sched_interact_update(td); 2043 sched_priority(td); 2044 thread_unlock(td); 2045} 2046 2047void 2048sched_preempt(struct thread *td) 2049{ 2050 struct tdq *tdq; 2051 2052 thread_lock(td); 2053 tdq = TDQ_SELF(); 2054 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2055 tdq->tdq_ipipending = 0; 2056 if (td->td_priority > tdq->tdq_lowpri) { 2057 int flags; 2058 2059 flags = SW_INVOL | SW_PREEMPT; 2060 if (td->td_critnest > 1) 2061 td->td_owepreempt = 1; 2062 else if (TD_IS_IDLETHREAD(td)) 2063 mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL); 2064 else 2065 mi_switch(flags | SWT_REMOTEPREEMPT, NULL); 2066 } 2067 thread_unlock(td); 2068} 2069 2070/* 2071 * Fix priorities on return to user-space. Priorities may be elevated due 2072 * to static priorities in msleep() or similar. 2073 */ 2074void 2075sched_userret(struct thread *td) 2076{ 2077 /* 2078 * XXX we cheat slightly on the locking here to avoid locking in 2079 * the usual case. Setting td_priority here is essentially an 2080 * incomplete workaround for not setting it properly elsewhere. 2081 * Now that some interrupt handlers are threads, not setting it 2082 * properly elsewhere can clobber it in the window between setting 2083 * it here and returning to user mode, so don't waste time setting 2084 * it perfectly here. 2085 */ 2086 KASSERT((td->td_flags & TDF_BORROWING) == 0, 2087 ("thread with borrowed priority returning to userland")); 2088 if (td->td_priority != td->td_user_pri) { 2089 thread_lock(td); 2090 td->td_priority = td->td_user_pri; 2091 td->td_base_pri = td->td_user_pri; 2092 tdq_setlowpri(TDQ_SELF(), td); 2093 thread_unlock(td); 2094 } 2095} 2096 2097/* 2098 * Handle a stathz tick. This is really only relevant for timeshare 2099 * threads. 2100 */ 2101void 2102sched_clock(struct thread *td) 2103{ 2104 struct tdq *tdq; 2105 struct td_sched *ts; 2106 2107 THREAD_LOCK_ASSERT(td, MA_OWNED); 2108 tdq = TDQ_SELF(); 2109#ifdef SMP 2110 /* 2111 * We run the long term load balancer infrequently on the first cpu. 2112 */ 2113 if (balance_tdq == tdq) { 2114 if (balance_ticks && --balance_ticks == 0) 2115 sched_balance(); 2116 } 2117#endif 2118 /* 2119 * Save the old switch count so we have a record of the last ticks 2120 * activity. Initialize the new switch count based on our load. 2121 * If there is some activity seed it to reflect that. 2122 */ 2123 tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt; 2124 tdq->tdq_switchcnt = tdq->tdq_load; 2125 /* 2126 * Advance the insert index once for each tick to ensure that all 2127 * threads get a chance to run. 2128 */ 2129 if (tdq->tdq_idx == tdq->tdq_ridx) { 2130 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; 2131 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) 2132 tdq->tdq_ridx = tdq->tdq_idx; 2133 } 2134 ts = td->td_sched; 2135 if (td->td_pri_class & PRI_FIFO_BIT) 2136 return; 2137 if (td->td_pri_class == PRI_TIMESHARE) { 2138 /* 2139 * We used a tick; charge it to the thread so 2140 * that we can compute our interactivity. 2141 */ 2142 td->td_sched->ts_runtime += tickincr; 2143 sched_interact_update(td); 2144 sched_priority(td); 2145 } 2146 /* 2147 * We used up one time slice. 2148 */ 2149 if (--ts->ts_slice > 0) 2150 return; 2151 /* 2152 * We're out of time, force a requeue at userret(). 2153 */ 2154 ts->ts_slice = sched_slice; 2155 td->td_flags |= TDF_NEEDRESCHED; 2156} 2157 2158/* 2159 * Called once per hz tick. Used for cpu utilization information. This 2160 * is easier than trying to scale based on stathz. 2161 */ 2162void 2163sched_tick(int cnt) 2164{ 2165 struct td_sched *ts; 2166 2167 ts = curthread->td_sched; 2168 /* 2169 * Ticks is updated asynchronously on a single cpu. Check here to 2170 * avoid incrementing ts_ticks multiple times in a single tick. 2171 */ 2172 if (ts->ts_incrtick == ticks) 2173 return; 2174 /* Adjust ticks for pctcpu */ 2175 ts->ts_ticks += cnt << SCHED_TICK_SHIFT; 2176 ts->ts_ltick = ticks; 2177 ts->ts_incrtick = ticks; 2178 /* 2179 * Update if we've exceeded our desired tick threshold by over one 2180 * second. 2181 */ 2182 if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick) 2183 sched_pctcpu_update(ts); 2184} 2185 2186/* 2187 * Return whether the current CPU has runnable tasks. Used for in-kernel 2188 * cooperative idle threads. 2189 */ 2190int 2191sched_runnable(void) 2192{ 2193 struct tdq *tdq; 2194 int load; 2195 2196 load = 1; 2197 2198 tdq = TDQ_SELF(); 2199 if ((curthread->td_flags & TDF_IDLETD) != 0) { 2200 if (tdq->tdq_load > 0) 2201 goto out; 2202 } else 2203 if (tdq->tdq_load - 1 > 0) 2204 goto out; 2205 load = 0; 2206out: 2207 return (load); 2208} 2209 2210/* 2211 * Choose the highest priority thread to run. The thread is removed from 2212 * the run-queue while running however the load remains. For SMP we set 2213 * the tdq in the global idle bitmask if it idles here. 2214 */ 2215struct thread * 2216sched_choose(void) 2217{ 2218 struct thread *td; 2219 struct tdq *tdq; 2220 2221 tdq = TDQ_SELF(); 2222 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2223 td = tdq_choose(tdq); 2224 if (td) { 2225 td->td_sched->ts_ltick = ticks; 2226 tdq_runq_rem(tdq, td); 2227 tdq->tdq_lowpri = td->td_priority; 2228 return (td); 2229 } 2230 tdq->tdq_lowpri = PRI_MAX_IDLE; 2231 return (PCPU_GET(idlethread)); 2232} 2233 2234/* 2235 * Set owepreempt if necessary. Preemption never happens directly in ULE, 2236 * we always request it once we exit a critical section. 2237 */ 2238static inline void 2239sched_setpreempt(struct thread *td) 2240{ 2241 struct thread *ctd; 2242 int cpri; 2243 int pri; 2244 2245 THREAD_LOCK_ASSERT(curthread, MA_OWNED); 2246 2247 ctd = curthread; 2248 pri = td->td_priority; 2249 cpri = ctd->td_priority; 2250 if (pri < cpri) 2251 ctd->td_flags |= TDF_NEEDRESCHED; 2252 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) 2253 return; 2254 if (!sched_shouldpreempt(pri, cpri, 0)) 2255 return; 2256 ctd->td_owepreempt = 1; 2257} 2258 2259/* 2260 * Add a thread to a thread queue. Select the appropriate runq and add the 2261 * thread to it. This is the internal function called when the tdq is 2262 * predetermined. 2263 */ 2264void 2265tdq_add(struct tdq *tdq, struct thread *td, int flags) 2266{ 2267 2268 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2269 KASSERT((td->td_inhibitors == 0), 2270 ("sched_add: trying to run inhibited thread")); 2271 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 2272 ("sched_add: bad thread state")); 2273 KASSERT(td->td_flags & TDF_INMEM, 2274 ("sched_add: thread swapped out")); 2275 2276 if (td->td_priority < tdq->tdq_lowpri) 2277 tdq->tdq_lowpri = td->td_priority; 2278 tdq_runq_add(tdq, td, flags); 2279 tdq_load_add(tdq, td); 2280} 2281 2282/* 2283 * Select the target thread queue and add a thread to it. Request 2284 * preemption or IPI a remote processor if required. 2285 */ 2286void 2287sched_add(struct thread *td, int flags) 2288{ 2289 struct tdq *tdq; 2290#ifdef SMP 2291 int cpu; 2292#endif 2293 2294 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", 2295 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 2296 sched_tdname(curthread)); 2297 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup", 2298 KTR_ATTR_LINKED, sched_tdname(td)); 2299 THREAD_LOCK_ASSERT(td, MA_OWNED); 2300 /* 2301 * Recalculate the priority before we select the target cpu or 2302 * run-queue. 2303 */ 2304 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 2305 sched_priority(td); 2306#ifdef SMP 2307 /* 2308 * Pick the destination cpu and if it isn't ours transfer to the 2309 * target cpu. 2310 */ 2311 cpu = sched_pickcpu(td, flags); 2312 tdq = sched_setcpu(td, cpu, flags); 2313 tdq_add(tdq, td, flags); 2314 if (cpu != PCPU_GET(cpuid)) { 2315 tdq_notify(tdq, td); 2316 return; 2317 } 2318#else 2319 tdq = TDQ_SELF(); 2320 TDQ_LOCK(tdq); 2321 /* 2322 * Now that the thread is moving to the run-queue, set the lock 2323 * to the scheduler's lock. 2324 */ 2325 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 2326 tdq_add(tdq, td, flags); 2327#endif 2328 if (!(flags & SRQ_YIELDING)) 2329 sched_setpreempt(td); 2330} 2331 2332/* 2333 * Remove a thread from a run-queue without running it. This is used 2334 * when we're stealing a thread from a remote queue. Otherwise all threads 2335 * exit by calling sched_exit_thread() and sched_throw() themselves. 2336 */ 2337void 2338sched_rem(struct thread *td) 2339{ 2340 struct tdq *tdq; 2341 2342 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem", 2343 "prio:%d", td->td_priority); 2344 tdq = TDQ_CPU(td->td_sched->ts_cpu); 2345 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2346 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2347 KASSERT(TD_ON_RUNQ(td), 2348 ("sched_rem: thread not on run queue")); 2349 tdq_runq_rem(tdq, td); 2350 tdq_load_rem(tdq, td); 2351 TD_SET_CAN_RUN(td); 2352 if (td->td_priority == tdq->tdq_lowpri) 2353 tdq_setlowpri(tdq, NULL); 2354} 2355 2356/* 2357 * Fetch cpu utilization information. Updates on demand. 2358 */ 2359fixpt_t 2360sched_pctcpu(struct thread *td) 2361{ 2362 fixpt_t pctcpu; 2363 struct td_sched *ts; 2364 2365 pctcpu = 0; 2366 ts = td->td_sched; 2367 if (ts == NULL) 2368 return (0); 2369 2370 THREAD_LOCK_ASSERT(td, MA_OWNED); 2371 if (ts->ts_ticks) { 2372 int rtick; 2373 2374 sched_pctcpu_update(ts); 2375 /* How many rtick per second ? */ 2376 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); 2377 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; 2378 } 2379 2380 return (pctcpu); 2381} 2382 2383/* 2384 * Enforce affinity settings for a thread. Called after adjustments to 2385 * cpumask. 2386 */ 2387void 2388sched_affinity(struct thread *td) 2389{ 2390#ifdef SMP 2391 struct td_sched *ts; 2392 2393 THREAD_LOCK_ASSERT(td, MA_OWNED); 2394 ts = td->td_sched; 2395 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) 2396 return; 2397 if (TD_ON_RUNQ(td)) { 2398 sched_rem(td); 2399 sched_add(td, SRQ_BORING); 2400 return; 2401 } 2402 if (!TD_IS_RUNNING(td)) 2403 return; 2404 /* 2405 * Force a switch before returning to userspace. If the 2406 * target thread is not running locally send an ipi to force 2407 * the issue. 2408 */ 2409 td->td_flags |= TDF_NEEDRESCHED; 2410 if (td != curthread) 2411 ipi_cpu(ts->ts_cpu, IPI_PREEMPT); 2412#endif 2413} 2414 2415/* 2416 * Bind a thread to a target cpu. 2417 */ 2418void 2419sched_bind(struct thread *td, int cpu) 2420{ 2421 struct td_sched *ts; 2422 2423 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 2424 KASSERT(td == curthread, ("sched_bind: can only bind curthread")); 2425 ts = td->td_sched; 2426 if (ts->ts_flags & TSF_BOUND) 2427 sched_unbind(td); 2428 KASSERT(THREAD_CAN_MIGRATE(td), ("%p must be migratable", td)); 2429 ts->ts_flags |= TSF_BOUND; 2430 sched_pin(); 2431 if (PCPU_GET(cpuid) == cpu) 2432 return; 2433 ts->ts_cpu = cpu; 2434 /* When we return from mi_switch we'll be on the correct cpu. */ 2435 mi_switch(SW_VOL, NULL); 2436} 2437 2438/* 2439 * Release a bound thread. 2440 */ 2441void 2442sched_unbind(struct thread *td) 2443{ 2444 struct td_sched *ts; 2445 2446 THREAD_LOCK_ASSERT(td, MA_OWNED); 2447 KASSERT(td == curthread, ("sched_unbind: can only bind curthread")); 2448 ts = td->td_sched; 2449 if ((ts->ts_flags & TSF_BOUND) == 0) 2450 return; 2451 ts->ts_flags &= ~TSF_BOUND; 2452 sched_unpin(); 2453} 2454 2455int 2456sched_is_bound(struct thread *td) 2457{ 2458 THREAD_LOCK_ASSERT(td, MA_OWNED); 2459 return (td->td_sched->ts_flags & TSF_BOUND); 2460} 2461 2462/* 2463 * Basic yield call. 2464 */ 2465void 2466sched_relinquish(struct thread *td) 2467{ 2468 thread_lock(td); 2469 mi_switch(SW_VOL | SWT_RELINQUISH, NULL); 2470 thread_unlock(td); 2471} 2472 2473/* 2474 * Return the total system load. 2475 */ 2476int 2477sched_load(void) 2478{ 2479#ifdef SMP 2480 int total; 2481 int i; 2482 2483 total = 0; 2484 CPU_FOREACH(i) 2485 total += TDQ_CPU(i)->tdq_sysload; 2486 return (total); 2487#else 2488 return (TDQ_SELF()->tdq_sysload); 2489#endif 2490} 2491 2492int 2493sched_sizeof_proc(void) 2494{ 2495 return (sizeof(struct proc)); 2496} 2497 2498int 2499sched_sizeof_thread(void) 2500{ 2501 return (sizeof(struct thread) + sizeof(struct td_sched)); 2502} 2503 2504#ifdef SMP 2505#define TDQ_IDLESPIN(tdq) \ 2506 ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0) 2507#else 2508#define TDQ_IDLESPIN(tdq) 1 2509#endif 2510 2511/* 2512 * The actual idle process. 2513 */ 2514void 2515sched_idletd(void *dummy) 2516{ 2517 struct thread *td; 2518 struct tdq *tdq; 2519 int switchcnt; 2520 int i; 2521 2522 mtx_assert(&Giant, MA_NOTOWNED); 2523 td = curthread; 2524 tdq = TDQ_SELF(); 2525 for (;;) { 2526#ifdef SMP 2527 if (tdq_idled(tdq) == 0) 2528 continue; 2529#endif 2530 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2531 /* 2532 * If we're switching very frequently, spin while checking 2533 * for load rather than entering a low power state that 2534 * may require an IPI. However, don't do any busy 2535 * loops while on SMT machines as this simply steals 2536 * cycles from cores doing useful work. 2537 */ 2538 if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) { 2539 for (i = 0; i < sched_idlespins; i++) { 2540 if (tdq->tdq_load) 2541 break; 2542 cpu_spinwait(); 2543 } 2544 } 2545 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2546 if (tdq->tdq_load == 0) { 2547 tdq->tdq_cpu_idle = 1; 2548 if (tdq->tdq_load == 0) { 2549 cpu_idle(switchcnt > sched_idlespinthresh * 4); 2550 tdq->tdq_switchcnt++; 2551 } 2552 tdq->tdq_cpu_idle = 0; 2553 } 2554 if (tdq->tdq_load) { 2555 thread_lock(td); 2556 mi_switch(SW_VOL | SWT_IDLE, NULL); 2557 thread_unlock(td); 2558 } 2559 } 2560} 2561 2562/* 2563 * A CPU is entering for the first time or a thread is exiting. 2564 */ 2565void 2566sched_throw(struct thread *td) 2567{ 2568 struct thread *newtd; 2569 struct tdq *tdq; 2570 2571 tdq = TDQ_SELF(); 2572 if (td == NULL) { 2573 /* Correct spinlock nesting and acquire the correct lock. */ 2574 TDQ_LOCK(tdq); 2575 spinlock_exit(); 2576 } else { 2577 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2578 tdq_load_rem(tdq, td); 2579 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 2580 } 2581 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 2582 newtd = choosethread(); 2583 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 2584 PCPU_SET(switchtime, cpu_ticks()); 2585 PCPU_SET(switchticks, ticks); 2586 cpu_throw(td, newtd); /* doesn't return */ 2587} 2588 2589/* 2590 * This is called from fork_exit(). Just acquire the correct locks and 2591 * let fork do the rest of the work. 2592 */ 2593void 2594sched_fork_exit(struct thread *td) 2595{ 2596 struct td_sched *ts; 2597 struct tdq *tdq; 2598 int cpuid; 2599 2600 /* 2601 * Finish setting up thread glue so that it begins execution in a 2602 * non-nested critical section with the scheduler lock held. 2603 */ 2604 cpuid = PCPU_GET(cpuid); 2605 tdq = TDQ_CPU(cpuid); 2606 ts = td->td_sched; 2607 if (TD_IS_IDLETHREAD(td)) 2608 td->td_lock = TDQ_LOCKPTR(tdq); 2609 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2610 td->td_oncpu = cpuid; 2611 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 2612 lock_profile_obtain_lock_success( 2613 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 2614} 2615 2616/* 2617 * Create on first use to catch odd startup conditons. 2618 */ 2619char * 2620sched_tdname(struct thread *td) 2621{ 2622#ifdef KTR 2623 struct td_sched *ts; 2624 2625 ts = td->td_sched; 2626 if (ts->ts_name[0] == '\0') 2627 snprintf(ts->ts_name, sizeof(ts->ts_name), 2628 "%s tid %d", td->td_name, td->td_tid); 2629 return (ts->ts_name); 2630#else 2631 return (td->td_name); 2632#endif 2633} 2634 2635#ifdef SMP 2636 2637/* 2638 * Build the CPU topology dump string. Is recursively called to collect 2639 * the topology tree. 2640 */ 2641static int 2642sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg, 2643 int indent) 2644{ 2645 int i, first; 2646 2647 sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent, 2648 "", 1 + indent / 2, cg->cg_level); 2649 sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"0x%x\">", indent, "", 2650 cg->cg_count, cg->cg_mask); 2651 first = TRUE; 2652 for (i = 0; i < MAXCPU; i++) { 2653 if ((cg->cg_mask & (1 << i)) != 0) { 2654 if (!first) 2655 sbuf_printf(sb, ", "); 2656 else 2657 first = FALSE; 2658 sbuf_printf(sb, "%d", i); 2659 } 2660 } 2661 sbuf_printf(sb, "</cpu>\n"); 2662 2663 if (cg->cg_flags != 0) { 2664 sbuf_printf(sb, "%*s <flags>", indent, ""); 2665 if ((cg->cg_flags & CG_FLAG_HTT) != 0) 2666 sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>"); 2667 if ((cg->cg_flags & CG_FLAG_THREAD) != 0) 2668 sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>"); 2669 if ((cg->cg_flags & CG_FLAG_SMT) != 0) 2670 sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>"); 2671 sbuf_printf(sb, "</flags>\n"); 2672 } 2673 2674 if (cg->cg_children > 0) { 2675 sbuf_printf(sb, "%*s <children>\n", indent, ""); 2676 for (i = 0; i < cg->cg_children; i++) 2677 sysctl_kern_sched_topology_spec_internal(sb, 2678 &cg->cg_child[i], indent+2); 2679 sbuf_printf(sb, "%*s </children>\n", indent, ""); 2680 } 2681 sbuf_printf(sb, "%*s</group>\n", indent, ""); 2682 return (0); 2683} 2684 2685/* 2686 * Sysctl handler for retrieving topology dump. It's a wrapper for 2687 * the recursive sysctl_kern_smp_topology_spec_internal(). 2688 */ 2689static int 2690sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS) 2691{ 2692 struct sbuf *topo; 2693 int err; 2694 2695 KASSERT(cpu_top != NULL, ("cpu_top isn't initialized")); 2696 2697 topo = sbuf_new(NULL, NULL, 500, SBUF_AUTOEXTEND); 2698 if (topo == NULL) 2699 return (ENOMEM); 2700 2701 sbuf_printf(topo, "<groups>\n"); 2702 err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1); 2703 sbuf_printf(topo, "</groups>\n"); 2704 2705 if (err == 0) { 2706 sbuf_finish(topo); 2707 err = SYSCTL_OUT(req, sbuf_data(topo), sbuf_len(topo)); 2708 } 2709 sbuf_delete(topo); 2710 return (err); 2711} 2712 2713#endif 2714 2715SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); 2716SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0, 2717 "Scheduler name"); 2718SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 2719 "Slice size for timeshare threads"); 2720SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, 2721 "Interactivity score threshold"); 2722SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh, 2723 0,"Min priority for preemption, lower priorities have greater precedence"); 2724SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 2725 0,"Controls whether static kernel priorities are assigned to sleeping threads."); 2726SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 2727 0,"Number of times idle will spin waiting for new work."); 2728SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW, &sched_idlespinthresh, 2729 0,"Threshold before we will permit idle spinning."); 2730#ifdef SMP 2731SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0, 2732 "Number of hz ticks to keep thread affinity for"); 2733SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, 2734 "Enables the long-term load balancer"); 2735SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW, 2736 &balance_interval, 0, 2737 "Average frequency in stathz ticks to run the long-term balancer"); 2738SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0, 2739 "Steals work from another hyper-threaded core on idle"); 2740SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0, 2741 "Attempts to steal work from other cores before idling"); 2742SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0, 2743 "Minimum load on remote cpu before we'll steal"); 2744 2745/* Retrieve SMP topology */ 2746SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING | 2747 CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A", 2748 "XML dump of detected CPU topology"); 2749 2750#endif 2751 2752/* ps compat. All cpu percentages from ULE are weighted. */ 2753static int ccpu = 0; 2754SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 2755