sched_ule.c revision 266330
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: stable/10/sys/kern/sched_ule.c 266330 2014-05-17 17:18:35Z ian $"); 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/sdt.h> 57#include <sys/smp.h> 58#include <sys/sx.h> 59#include <sys/sysctl.h> 60#include <sys/sysproto.h> 61#include <sys/turnstile.h> 62#include <sys/umtx.h> 63#include <sys/vmmeter.h> 64#include <sys/cpuset.h> 65#include <sys/sbuf.h> 66 67#ifdef HWPMC_HOOKS 68#include <sys/pmckern.h> 69#endif 70 71#ifdef KDTRACE_HOOKS 72#include <sys/dtrace_bsd.h> 73int dtrace_vtime_active; 74dtrace_vtime_switch_func_t dtrace_vtime_switch_func; 75#endif 76 77#include <machine/cpu.h> 78#include <machine/smp.h> 79 80#define KTR_ULE 0 81 82#define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX))) 83#define TDQ_NAME_LEN (sizeof("sched lock ") + sizeof(__XSTRING(MAXCPU))) 84#define TDQ_LOADNAME_LEN (sizeof("CPU ") + sizeof(__XSTRING(MAXCPU)) - 1 + sizeof(" load")) 85 86/* 87 * Thread scheduler specific section. All fields are protected 88 * by the thread lock. 89 */ 90struct td_sched { 91 struct runq *ts_runq; /* Run-queue we're queued on. */ 92 short ts_flags; /* TSF_* flags. */ 93 u_char ts_cpu; /* CPU that we have affinity for. */ 94 int ts_rltick; /* Real last tick, for affinity. */ 95 int ts_slice; /* Ticks of slice remaining. */ 96 u_int ts_slptime; /* Number of ticks we vol. slept */ 97 u_int ts_runtime; /* Number of ticks we were running */ 98 int ts_ltick; /* Last tick that we were running on */ 99 int ts_ftick; /* First tick that we were running on */ 100 int ts_ticks; /* Tick count */ 101#ifdef KTR 102 char ts_name[TS_NAME_LEN]; 103#endif 104}; 105/* flags kept in ts_flags */ 106#define TSF_BOUND 0x0001 /* Thread can not migrate. */ 107#define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */ 108 109static struct td_sched td_sched0; 110 111#define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0) 112#define THREAD_CAN_SCHED(td, cpu) \ 113 CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask) 114 115/* 116 * Priority ranges used for interactive and non-interactive timeshare 117 * threads. The timeshare priorities are split up into four ranges. 118 * The first range handles interactive threads. The last three ranges 119 * (NHALF, x, and NHALF) handle non-interactive threads with the outer 120 * ranges supporting nice values. 121 */ 122#define PRI_TIMESHARE_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1) 123#define PRI_INTERACT_RANGE ((PRI_TIMESHARE_RANGE - SCHED_PRI_NRESV) / 2) 124#define PRI_BATCH_RANGE (PRI_TIMESHARE_RANGE - PRI_INTERACT_RANGE) 125 126#define PRI_MIN_INTERACT PRI_MIN_TIMESHARE 127#define PRI_MAX_INTERACT (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE - 1) 128#define PRI_MIN_BATCH (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE) 129#define PRI_MAX_BATCH PRI_MAX_TIMESHARE 130 131/* 132 * Cpu percentage computation macros and defines. 133 * 134 * SCHED_TICK_SECS: Number of seconds to average the cpu usage across. 135 * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across. 136 * SCHED_TICK_MAX: Maximum number of ticks before scaling back. 137 * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results. 138 * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count. 139 * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks. 140 */ 141#define SCHED_TICK_SECS 10 142#define SCHED_TICK_TARG (hz * SCHED_TICK_SECS) 143#define SCHED_TICK_MAX (SCHED_TICK_TARG + hz) 144#define SCHED_TICK_SHIFT 10 145#define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT) 146#define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz)) 147 148/* 149 * These macros determine priorities for non-interactive threads. They are 150 * assigned a priority based on their recent cpu utilization as expressed 151 * by the ratio of ticks to the tick total. NHALF priorities at the start 152 * and end of the MIN to MAX timeshare range are only reachable with negative 153 * or positive nice respectively. 154 * 155 * PRI_RANGE: Priority range for utilization dependent priorities. 156 * PRI_NRESV: Number of nice values. 157 * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total. 158 * PRI_NICE: Determines the part of the priority inherited from nice. 159 */ 160#define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN) 161#define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) 162#define SCHED_PRI_MIN (PRI_MIN_BATCH + SCHED_PRI_NHALF) 163#define SCHED_PRI_MAX (PRI_MAX_BATCH - SCHED_PRI_NHALF) 164#define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN + 1) 165#define SCHED_PRI_TICKS(ts) \ 166 (SCHED_TICK_HZ((ts)) / \ 167 (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE)) 168#define SCHED_PRI_NICE(nice) (nice) 169 170/* 171 * These determine the interactivity of a process. Interactivity differs from 172 * cpu utilization in that it expresses the voluntary time slept vs time ran 173 * while cpu utilization includes all time not running. This more accurately 174 * models the intent of the thread. 175 * 176 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 177 * before throttling back. 178 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. 179 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 180 * INTERACT_THRESH: Threshold for placement on the current runq. 181 */ 182#define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT) 183#define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT) 184#define SCHED_INTERACT_MAX (100) 185#define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 186#define SCHED_INTERACT_THRESH (30) 187 188/* 189 * These parameters determine the slice behavior for batch work. 190 */ 191#define SCHED_SLICE_DEFAULT_DIVISOR 10 /* ~94 ms, 12 stathz ticks. */ 192#define SCHED_SLICE_MIN_DIVISOR 6 /* DEFAULT/MIN = ~16 ms. */ 193 194/* Flags kept in td_flags. */ 195#define TDF_SLICEEND TDF_SCHED2 /* Thread time slice is over. */ 196 197/* 198 * tickincr: Converts a stathz tick into a hz domain scaled by 199 * the shift factor. Without the shift the error rate 200 * due to rounding would be unacceptably high. 201 * realstathz: stathz is sometimes 0 and run off of hz. 202 * sched_slice: Runtime of each thread before rescheduling. 203 * preempt_thresh: Priority threshold for preemption and remote IPIs. 204 */ 205static int sched_interact = SCHED_INTERACT_THRESH; 206static int tickincr = 8 << SCHED_TICK_SHIFT; 207static int realstathz = 127; /* reset during boot. */ 208static int sched_slice = 10; /* reset during boot. */ 209static int sched_slice_min = 1; /* reset during boot. */ 210#ifdef PREEMPTION 211#ifdef FULL_PREEMPTION 212static int preempt_thresh = PRI_MAX_IDLE; 213#else 214static int preempt_thresh = PRI_MIN_KERN; 215#endif 216#else 217static int preempt_thresh = 0; 218#endif 219static int static_boost = PRI_MIN_BATCH; 220static int sched_idlespins = 10000; 221static int sched_idlespinthresh = -1; 222 223/* 224 * tdq - per processor runqs and statistics. All fields are protected by the 225 * tdq_lock. The load and lowpri may be accessed without to avoid excess 226 * locking in sched_pickcpu(); 227 */ 228struct tdq { 229 /* 230 * Ordered to improve efficiency of cpu_search() and switch(). 231 * tdq_lock is padded to avoid false sharing with tdq_load and 232 * tdq_cpu_idle. 233 */ 234 struct mtx_padalign tdq_lock; /* run queue lock. */ 235 struct cpu_group *tdq_cg; /* Pointer to cpu topology. */ 236 volatile int tdq_load; /* Aggregate load. */ 237 volatile int tdq_cpu_idle; /* cpu_idle() is active. */ 238 int tdq_sysload; /* For loadavg, !ITHD load. */ 239 int tdq_transferable; /* Transferable thread count. */ 240 short tdq_switchcnt; /* Switches this tick. */ 241 short tdq_oldswitchcnt; /* Switches last tick. */ 242 u_char tdq_lowpri; /* Lowest priority thread. */ 243 u_char tdq_ipipending; /* IPI pending. */ 244 u_char tdq_idx; /* Current insert index. */ 245 u_char tdq_ridx; /* Current removal index. */ 246 struct runq tdq_realtime; /* real-time run queue. */ 247 struct runq tdq_timeshare; /* timeshare run queue. */ 248 struct runq tdq_idle; /* Queue of IDLE threads. */ 249 char tdq_name[TDQ_NAME_LEN]; 250#ifdef KTR 251 char tdq_loadname[TDQ_LOADNAME_LEN]; 252#endif 253} __aligned(64); 254 255/* Idle thread states and config. */ 256#define TDQ_RUNNING 1 257#define TDQ_IDLE 2 258 259#ifdef SMP 260struct cpu_group *cpu_top; /* CPU topology */ 261 262#define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000)) 263#define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity)) 264 265/* 266 * Run-time tunables. 267 */ 268static int rebalance = 1; 269static int balance_interval = 128; /* Default set in sched_initticks(). */ 270static int affinity; 271static int steal_idle = 1; 272static int steal_thresh = 2; 273 274/* 275 * One thread queue per processor. 276 */ 277static struct tdq tdq_cpu[MAXCPU]; 278static struct tdq *balance_tdq; 279static int balance_ticks; 280static DPCPU_DEFINE(uint32_t, randomval); 281 282#define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)]) 283#define TDQ_CPU(x) (&tdq_cpu[(x)]) 284#define TDQ_ID(x) ((int)((x) - tdq_cpu)) 285#else /* !SMP */ 286static struct tdq tdq_cpu; 287 288#define TDQ_ID(x) (0) 289#define TDQ_SELF() (&tdq_cpu) 290#define TDQ_CPU(x) (&tdq_cpu) 291#endif 292 293#define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type)) 294#define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t))) 295#define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f)) 296#define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t))) 297#define TDQ_LOCKPTR(t) ((struct mtx *)(&(t)->tdq_lock)) 298 299static void sched_priority(struct thread *); 300static void sched_thread_priority(struct thread *, u_char); 301static int sched_interact_score(struct thread *); 302static void sched_interact_update(struct thread *); 303static void sched_interact_fork(struct thread *); 304static void sched_pctcpu_update(struct td_sched *, int); 305 306/* Operations on per processor queues */ 307static struct thread *tdq_choose(struct tdq *); 308static void tdq_setup(struct tdq *); 309static void tdq_load_add(struct tdq *, struct thread *); 310static void tdq_load_rem(struct tdq *, struct thread *); 311static __inline void tdq_runq_add(struct tdq *, struct thread *, int); 312static __inline void tdq_runq_rem(struct tdq *, struct thread *); 313static inline int sched_shouldpreempt(int, int, int); 314void tdq_print(int cpu); 315static void runq_print(struct runq *rq); 316static void tdq_add(struct tdq *, struct thread *, int); 317#ifdef SMP 318static int tdq_move(struct tdq *, struct tdq *); 319static int tdq_idled(struct tdq *); 320static void tdq_notify(struct tdq *, struct thread *); 321static struct thread *tdq_steal(struct tdq *, int); 322static struct thread *runq_steal(struct runq *, int); 323static int sched_pickcpu(struct thread *, int); 324static void sched_balance(void); 325static int sched_balance_pair(struct tdq *, struct tdq *); 326static inline struct tdq *sched_setcpu(struct thread *, int, int); 327static inline void thread_unblock_switch(struct thread *, struct mtx *); 328static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int); 329static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS); 330static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, 331 struct cpu_group *cg, int indent); 332#endif 333 334static void sched_setup(void *dummy); 335SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL); 336 337static void sched_initticks(void *dummy); 338SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, 339 NULL); 340 341SDT_PROVIDER_DEFINE(sched); 342 343SDT_PROBE_DEFINE3(sched, , , change__pri, "struct thread *", 344 "struct proc *", "uint8_t"); 345SDT_PROBE_DEFINE3(sched, , , dequeue, "struct thread *", 346 "struct proc *", "void *"); 347SDT_PROBE_DEFINE4(sched, , , enqueue, "struct thread *", 348 "struct proc *", "void *", "int"); 349SDT_PROBE_DEFINE4(sched, , , lend__pri, "struct thread *", 350 "struct proc *", "uint8_t", "struct thread *"); 351SDT_PROBE_DEFINE2(sched, , , load__change, "int", "int"); 352SDT_PROBE_DEFINE2(sched, , , off__cpu, "struct thread *", 353 "struct proc *"); 354SDT_PROBE_DEFINE(sched, , , on__cpu); 355SDT_PROBE_DEFINE(sched, , , remain__cpu); 356SDT_PROBE_DEFINE2(sched, , , surrender, "struct thread *", 357 "struct proc *"); 358 359/* 360 * Print the threads waiting on a run-queue. 361 */ 362static void 363runq_print(struct runq *rq) 364{ 365 struct rqhead *rqh; 366 struct thread *td; 367 int pri; 368 int j; 369 int i; 370 371 for (i = 0; i < RQB_LEN; i++) { 372 printf("\t\trunq bits %d 0x%zx\n", 373 i, rq->rq_status.rqb_bits[i]); 374 for (j = 0; j < RQB_BPW; j++) 375 if (rq->rq_status.rqb_bits[i] & (1ul << j)) { 376 pri = j + (i << RQB_L2BPW); 377 rqh = &rq->rq_queues[pri]; 378 TAILQ_FOREACH(td, rqh, td_runq) { 379 printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n", 380 td, td->td_name, td->td_priority, 381 td->td_rqindex, pri); 382 } 383 } 384 } 385} 386 387/* 388 * Print the status of a per-cpu thread queue. Should be a ddb show cmd. 389 */ 390void 391tdq_print(int cpu) 392{ 393 struct tdq *tdq; 394 395 tdq = TDQ_CPU(cpu); 396 397 printf("tdq %d:\n", TDQ_ID(tdq)); 398 printf("\tlock %p\n", TDQ_LOCKPTR(tdq)); 399 printf("\tLock name: %s\n", tdq->tdq_name); 400 printf("\tload: %d\n", tdq->tdq_load); 401 printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt); 402 printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt); 403 printf("\ttimeshare idx: %d\n", tdq->tdq_idx); 404 printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx); 405 printf("\tload transferable: %d\n", tdq->tdq_transferable); 406 printf("\tlowest priority: %d\n", tdq->tdq_lowpri); 407 printf("\trealtime runq:\n"); 408 runq_print(&tdq->tdq_realtime); 409 printf("\ttimeshare runq:\n"); 410 runq_print(&tdq->tdq_timeshare); 411 printf("\tidle runq:\n"); 412 runq_print(&tdq->tdq_idle); 413} 414 415static inline int 416sched_shouldpreempt(int pri, int cpri, int remote) 417{ 418 /* 419 * If the new priority is not better than the current priority there is 420 * nothing to do. 421 */ 422 if (pri >= cpri) 423 return (0); 424 /* 425 * Always preempt idle. 426 */ 427 if (cpri >= PRI_MIN_IDLE) 428 return (1); 429 /* 430 * If preemption is disabled don't preempt others. 431 */ 432 if (preempt_thresh == 0) 433 return (0); 434 /* 435 * Preempt if we exceed the threshold. 436 */ 437 if (pri <= preempt_thresh) 438 return (1); 439 /* 440 * If we're interactive or better and there is non-interactive 441 * or worse running preempt only remote processors. 442 */ 443 if (remote && pri <= PRI_MAX_INTERACT && cpri > PRI_MAX_INTERACT) 444 return (1); 445 return (0); 446} 447 448/* 449 * Add a thread to the actual run-queue. Keeps transferable counts up to 450 * date with what is actually on the run-queue. Selects the correct 451 * queue position for timeshare threads. 452 */ 453static __inline void 454tdq_runq_add(struct tdq *tdq, struct thread *td, int flags) 455{ 456 struct td_sched *ts; 457 u_char pri; 458 459 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 460 THREAD_LOCK_ASSERT(td, MA_OWNED); 461 462 pri = td->td_priority; 463 ts = td->td_sched; 464 TD_SET_RUNQ(td); 465 if (THREAD_CAN_MIGRATE(td)) { 466 tdq->tdq_transferable++; 467 ts->ts_flags |= TSF_XFERABLE; 468 } 469 if (pri < PRI_MIN_BATCH) { 470 ts->ts_runq = &tdq->tdq_realtime; 471 } else if (pri <= PRI_MAX_BATCH) { 472 ts->ts_runq = &tdq->tdq_timeshare; 473 KASSERT(pri <= PRI_MAX_BATCH && pri >= PRI_MIN_BATCH, 474 ("Invalid priority %d on timeshare runq", pri)); 475 /* 476 * This queue contains only priorities between MIN and MAX 477 * realtime. Use the whole queue to represent these values. 478 */ 479 if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) { 480 pri = RQ_NQS * (pri - PRI_MIN_BATCH) / PRI_BATCH_RANGE; 481 pri = (pri + tdq->tdq_idx) % RQ_NQS; 482 /* 483 * This effectively shortens the queue by one so we 484 * can have a one slot difference between idx and 485 * ridx while we wait for threads to drain. 486 */ 487 if (tdq->tdq_ridx != tdq->tdq_idx && 488 pri == tdq->tdq_ridx) 489 pri = (unsigned char)(pri - 1) % RQ_NQS; 490 } else 491 pri = tdq->tdq_ridx; 492 runq_add_pri(ts->ts_runq, td, pri, flags); 493 return; 494 } else 495 ts->ts_runq = &tdq->tdq_idle; 496 runq_add(ts->ts_runq, td, flags); 497} 498 499/* 500 * Remove a thread from a run-queue. This typically happens when a thread 501 * is selected to run. Running threads are not on the queue and the 502 * transferable count does not reflect them. 503 */ 504static __inline void 505tdq_runq_rem(struct tdq *tdq, struct thread *td) 506{ 507 struct td_sched *ts; 508 509 ts = td->td_sched; 510 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 511 KASSERT(ts->ts_runq != NULL, 512 ("tdq_runq_remove: thread %p null ts_runq", td)); 513 if (ts->ts_flags & TSF_XFERABLE) { 514 tdq->tdq_transferable--; 515 ts->ts_flags &= ~TSF_XFERABLE; 516 } 517 if (ts->ts_runq == &tdq->tdq_timeshare) { 518 if (tdq->tdq_idx != tdq->tdq_ridx) 519 runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx); 520 else 521 runq_remove_idx(ts->ts_runq, td, NULL); 522 } else 523 runq_remove(ts->ts_runq, td); 524} 525 526/* 527 * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load 528 * for this thread to the referenced thread queue. 529 */ 530static void 531tdq_load_add(struct tdq *tdq, struct thread *td) 532{ 533 534 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 535 THREAD_LOCK_ASSERT(td, MA_OWNED); 536 537 tdq->tdq_load++; 538 if ((td->td_flags & TDF_NOLOAD) == 0) 539 tdq->tdq_sysload++; 540 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load); 541 SDT_PROBE2(sched, , , load__change, (int)TDQ_ID(tdq), tdq->tdq_load); 542} 543 544/* 545 * Remove the load from a thread that is transitioning to a sleep state or 546 * exiting. 547 */ 548static void 549tdq_load_rem(struct tdq *tdq, struct thread *td) 550{ 551 552 THREAD_LOCK_ASSERT(td, MA_OWNED); 553 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 554 KASSERT(tdq->tdq_load != 0, 555 ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq))); 556 557 tdq->tdq_load--; 558 if ((td->td_flags & TDF_NOLOAD) == 0) 559 tdq->tdq_sysload--; 560 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load); 561 SDT_PROBE2(sched, , , load__change, (int)TDQ_ID(tdq), tdq->tdq_load); 562} 563 564/* 565 * Bound timeshare latency by decreasing slice size as load increases. We 566 * consider the maximum latency as the sum of the threads waiting to run 567 * aside from curthread and target no more than sched_slice latency but 568 * no less than sched_slice_min runtime. 569 */ 570static inline int 571tdq_slice(struct tdq *tdq) 572{ 573 int load; 574 575 /* 576 * It is safe to use sys_load here because this is called from 577 * contexts where timeshare threads are running and so there 578 * cannot be higher priority load in the system. 579 */ 580 load = tdq->tdq_sysload - 1; 581 if (load >= SCHED_SLICE_MIN_DIVISOR) 582 return (sched_slice_min); 583 if (load <= 1) 584 return (sched_slice); 585 return (sched_slice / load); 586} 587 588/* 589 * Set lowpri to its exact value by searching the run-queue and 590 * evaluating curthread. curthread may be passed as an optimization. 591 */ 592static void 593tdq_setlowpri(struct tdq *tdq, struct thread *ctd) 594{ 595 struct thread *td; 596 597 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 598 if (ctd == NULL) 599 ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread; 600 td = tdq_choose(tdq); 601 if (td == NULL || td->td_priority > ctd->td_priority) 602 tdq->tdq_lowpri = ctd->td_priority; 603 else 604 tdq->tdq_lowpri = td->td_priority; 605} 606 607#ifdef SMP 608struct cpu_search { 609 cpuset_t cs_mask; 610 u_int cs_prefer; 611 int cs_pri; /* Min priority for low. */ 612 int cs_limit; /* Max load for low, min load for high. */ 613 int cs_cpu; 614 int cs_load; 615}; 616 617#define CPU_SEARCH_LOWEST 0x1 618#define CPU_SEARCH_HIGHEST 0x2 619#define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST) 620 621#define CPUSET_FOREACH(cpu, mask) \ 622 for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++) \ 623 if (CPU_ISSET(cpu, &mask)) 624 625static __inline int cpu_search(const struct cpu_group *cg, struct cpu_search *low, 626 struct cpu_search *high, const int match); 627int cpu_search_lowest(const struct cpu_group *cg, struct cpu_search *low); 628int cpu_search_highest(const struct cpu_group *cg, struct cpu_search *high); 629int cpu_search_both(const struct cpu_group *cg, struct cpu_search *low, 630 struct cpu_search *high); 631 632/* 633 * Search the tree of cpu_groups for the lowest or highest loaded cpu 634 * according to the match argument. This routine actually compares the 635 * load on all paths through the tree and finds the least loaded cpu on 636 * the least loaded path, which may differ from the least loaded cpu in 637 * the system. This balances work among caches and busses. 638 * 639 * This inline is instantiated in three forms below using constants for the 640 * match argument. It is reduced to the minimum set for each case. It is 641 * also recursive to the depth of the tree. 642 */ 643static __inline int 644cpu_search(const struct cpu_group *cg, struct cpu_search *low, 645 struct cpu_search *high, const int match) 646{ 647 struct cpu_search lgroup; 648 struct cpu_search hgroup; 649 cpuset_t cpumask; 650 struct cpu_group *child; 651 struct tdq *tdq; 652 int cpu, i, hload, lload, load, total, rnd, *rndptr; 653 654 total = 0; 655 cpumask = cg->cg_mask; 656 if (match & CPU_SEARCH_LOWEST) { 657 lload = INT_MAX; 658 lgroup = *low; 659 } 660 if (match & CPU_SEARCH_HIGHEST) { 661 hload = INT_MIN; 662 hgroup = *high; 663 } 664 665 /* Iterate through the child CPU groups and then remaining CPUs. */ 666 for (i = cg->cg_children, cpu = mp_maxid; ; ) { 667 if (i == 0) { 668#ifdef HAVE_INLINE_FFSL 669 cpu = CPU_FFS(&cpumask) - 1; 670#else 671 while (cpu >= 0 && !CPU_ISSET(cpu, &cpumask)) 672 cpu--; 673#endif 674 if (cpu < 0) 675 break; 676 child = NULL; 677 } else 678 child = &cg->cg_child[i - 1]; 679 680 if (match & CPU_SEARCH_LOWEST) 681 lgroup.cs_cpu = -1; 682 if (match & CPU_SEARCH_HIGHEST) 683 hgroup.cs_cpu = -1; 684 if (child) { /* Handle child CPU group. */ 685 CPU_NAND(&cpumask, &child->cg_mask); 686 switch (match) { 687 case CPU_SEARCH_LOWEST: 688 load = cpu_search_lowest(child, &lgroup); 689 break; 690 case CPU_SEARCH_HIGHEST: 691 load = cpu_search_highest(child, &hgroup); 692 break; 693 case CPU_SEARCH_BOTH: 694 load = cpu_search_both(child, &lgroup, &hgroup); 695 break; 696 } 697 } else { /* Handle child CPU. */ 698 CPU_CLR(cpu, &cpumask); 699 tdq = TDQ_CPU(cpu); 700 load = tdq->tdq_load * 256; 701 rndptr = DPCPU_PTR(randomval); 702 rnd = (*rndptr = *rndptr * 69069 + 5) >> 26; 703 if (match & CPU_SEARCH_LOWEST) { 704 if (cpu == low->cs_prefer) 705 load -= 64; 706 /* If that CPU is allowed and get data. */ 707 if (tdq->tdq_lowpri > lgroup.cs_pri && 708 tdq->tdq_load <= lgroup.cs_limit && 709 CPU_ISSET(cpu, &lgroup.cs_mask)) { 710 lgroup.cs_cpu = cpu; 711 lgroup.cs_load = load - rnd; 712 } 713 } 714 if (match & CPU_SEARCH_HIGHEST) 715 if (tdq->tdq_load >= hgroup.cs_limit && 716 tdq->tdq_transferable && 717 CPU_ISSET(cpu, &hgroup.cs_mask)) { 718 hgroup.cs_cpu = cpu; 719 hgroup.cs_load = load - rnd; 720 } 721 } 722 total += load; 723 724 /* We have info about child item. Compare it. */ 725 if (match & CPU_SEARCH_LOWEST) { 726 if (lgroup.cs_cpu >= 0 && 727 (load < lload || 728 (load == lload && lgroup.cs_load < low->cs_load))) { 729 lload = load; 730 low->cs_cpu = lgroup.cs_cpu; 731 low->cs_load = lgroup.cs_load; 732 } 733 } 734 if (match & CPU_SEARCH_HIGHEST) 735 if (hgroup.cs_cpu >= 0 && 736 (load > hload || 737 (load == hload && hgroup.cs_load > high->cs_load))) { 738 hload = load; 739 high->cs_cpu = hgroup.cs_cpu; 740 high->cs_load = hgroup.cs_load; 741 } 742 if (child) { 743 i--; 744 if (i == 0 && CPU_EMPTY(&cpumask)) 745 break; 746 } 747#ifndef HAVE_INLINE_FFSL 748 else 749 cpu--; 750#endif 751 } 752 return (total); 753} 754 755/* 756 * cpu_search instantiations must pass constants to maintain the inline 757 * optimization. 758 */ 759int 760cpu_search_lowest(const struct cpu_group *cg, struct cpu_search *low) 761{ 762 return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST); 763} 764 765int 766cpu_search_highest(const struct cpu_group *cg, struct cpu_search *high) 767{ 768 return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST); 769} 770 771int 772cpu_search_both(const struct cpu_group *cg, struct cpu_search *low, 773 struct cpu_search *high) 774{ 775 return cpu_search(cg, low, high, CPU_SEARCH_BOTH); 776} 777 778/* 779 * Find the cpu with the least load via the least loaded path that has a 780 * lowpri greater than pri pri. A pri of -1 indicates any priority is 781 * acceptable. 782 */ 783static inline int 784sched_lowest(const struct cpu_group *cg, cpuset_t mask, int pri, int maxload, 785 int prefer) 786{ 787 struct cpu_search low; 788 789 low.cs_cpu = -1; 790 low.cs_prefer = prefer; 791 low.cs_mask = mask; 792 low.cs_pri = pri; 793 low.cs_limit = maxload; 794 cpu_search_lowest(cg, &low); 795 return low.cs_cpu; 796} 797 798/* 799 * Find the cpu with the highest load via the highest loaded path. 800 */ 801static inline int 802sched_highest(const struct cpu_group *cg, cpuset_t mask, int minload) 803{ 804 struct cpu_search high; 805 806 high.cs_cpu = -1; 807 high.cs_mask = mask; 808 high.cs_limit = minload; 809 cpu_search_highest(cg, &high); 810 return high.cs_cpu; 811} 812 813static void 814sched_balance_group(struct cpu_group *cg) 815{ 816 cpuset_t hmask, lmask; 817 int high, low, anylow; 818 819 CPU_FILL(&hmask); 820 for (;;) { 821 high = sched_highest(cg, hmask, 1); 822 /* Stop if there is no more CPU with transferrable threads. */ 823 if (high == -1) 824 break; 825 CPU_CLR(high, &hmask); 826 CPU_COPY(&hmask, &lmask); 827 /* Stop if there is no more CPU left for low. */ 828 if (CPU_EMPTY(&lmask)) 829 break; 830 anylow = 1; 831nextlow: 832 low = sched_lowest(cg, lmask, -1, 833 TDQ_CPU(high)->tdq_load - 1, high); 834 /* Stop if we looked well and found no less loaded CPU. */ 835 if (anylow && low == -1) 836 break; 837 /* Go to next high if we found no less loaded CPU. */ 838 if (low == -1) 839 continue; 840 /* Transfer thread from high to low. */ 841 if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low))) { 842 /* CPU that got thread can no longer be a donor. */ 843 CPU_CLR(low, &hmask); 844 } else { 845 /* 846 * If failed, then there is no threads on high 847 * that can run on this low. Drop low from low 848 * mask and look for different one. 849 */ 850 CPU_CLR(low, &lmask); 851 anylow = 0; 852 goto nextlow; 853 } 854 } 855} 856 857static void 858sched_balance(void) 859{ 860 struct tdq *tdq; 861 862 /* 863 * Select a random time between .5 * balance_interval and 864 * 1.5 * balance_interval. 865 */ 866 balance_ticks = max(balance_interval / 2, 1); 867 balance_ticks += random() % balance_interval; 868 if (smp_started == 0 || rebalance == 0) 869 return; 870 tdq = TDQ_SELF(); 871 TDQ_UNLOCK(tdq); 872 sched_balance_group(cpu_top); 873 TDQ_LOCK(tdq); 874} 875 876/* 877 * Lock two thread queues using their address to maintain lock order. 878 */ 879static void 880tdq_lock_pair(struct tdq *one, struct tdq *two) 881{ 882 if (one < two) { 883 TDQ_LOCK(one); 884 TDQ_LOCK_FLAGS(two, MTX_DUPOK); 885 } else { 886 TDQ_LOCK(two); 887 TDQ_LOCK_FLAGS(one, MTX_DUPOK); 888 } 889} 890 891/* 892 * Unlock two thread queues. Order is not important here. 893 */ 894static void 895tdq_unlock_pair(struct tdq *one, struct tdq *two) 896{ 897 TDQ_UNLOCK(one); 898 TDQ_UNLOCK(two); 899} 900 901/* 902 * Transfer load between two imbalanced thread queues. 903 */ 904static int 905sched_balance_pair(struct tdq *high, struct tdq *low) 906{ 907 int moved; 908 int cpu; 909 910 tdq_lock_pair(high, low); 911 moved = 0; 912 /* 913 * Determine what the imbalance is and then adjust that to how many 914 * threads we actually have to give up (transferable). 915 */ 916 if (high->tdq_transferable != 0 && high->tdq_load > low->tdq_load && 917 (moved = tdq_move(high, low)) > 0) { 918 /* 919 * In case the target isn't the current cpu IPI it to force a 920 * reschedule with the new workload. 921 */ 922 cpu = TDQ_ID(low); 923 if (cpu != PCPU_GET(cpuid)) 924 ipi_cpu(cpu, IPI_PREEMPT); 925 } 926 tdq_unlock_pair(high, low); 927 return (moved); 928} 929 930/* 931 * Move a thread from one thread queue to another. 932 */ 933static int 934tdq_move(struct tdq *from, struct tdq *to) 935{ 936 struct td_sched *ts; 937 struct thread *td; 938 struct tdq *tdq; 939 int cpu; 940 941 TDQ_LOCK_ASSERT(from, MA_OWNED); 942 TDQ_LOCK_ASSERT(to, MA_OWNED); 943 944 tdq = from; 945 cpu = TDQ_ID(to); 946 td = tdq_steal(tdq, cpu); 947 if (td == NULL) 948 return (0); 949 ts = td->td_sched; 950 /* 951 * Although the run queue is locked the thread may be blocked. Lock 952 * it to clear this and acquire the run-queue lock. 953 */ 954 thread_lock(td); 955 /* Drop recursive lock on from acquired via thread_lock(). */ 956 TDQ_UNLOCK(from); 957 sched_rem(td); 958 ts->ts_cpu = cpu; 959 td->td_lock = TDQ_LOCKPTR(to); 960 tdq_add(to, td, SRQ_YIELDING); 961 return (1); 962} 963 964/* 965 * This tdq has idled. Try to steal a thread from another cpu and switch 966 * to it. 967 */ 968static int 969tdq_idled(struct tdq *tdq) 970{ 971 struct cpu_group *cg; 972 struct tdq *steal; 973 cpuset_t mask; 974 int thresh; 975 int cpu; 976 977 if (smp_started == 0 || steal_idle == 0) 978 return (1); 979 CPU_FILL(&mask); 980 CPU_CLR(PCPU_GET(cpuid), &mask); 981 /* We don't want to be preempted while we're iterating. */ 982 spinlock_enter(); 983 for (cg = tdq->tdq_cg; cg != NULL; ) { 984 if ((cg->cg_flags & CG_FLAG_THREAD) == 0) 985 thresh = steal_thresh; 986 else 987 thresh = 1; 988 cpu = sched_highest(cg, mask, thresh); 989 if (cpu == -1) { 990 cg = cg->cg_parent; 991 continue; 992 } 993 steal = TDQ_CPU(cpu); 994 CPU_CLR(cpu, &mask); 995 tdq_lock_pair(tdq, steal); 996 if (steal->tdq_load < thresh || steal->tdq_transferable == 0) { 997 tdq_unlock_pair(tdq, steal); 998 continue; 999 } 1000 /* 1001 * If a thread was added while interrupts were disabled don't 1002 * steal one here. If we fail to acquire one due to affinity 1003 * restrictions loop again with this cpu removed from the 1004 * set. 1005 */ 1006 if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) { 1007 tdq_unlock_pair(tdq, steal); 1008 continue; 1009 } 1010 spinlock_exit(); 1011 TDQ_UNLOCK(steal); 1012 mi_switch(SW_VOL | SWT_IDLE, NULL); 1013 thread_unlock(curthread); 1014 1015 return (0); 1016 } 1017 spinlock_exit(); 1018 return (1); 1019} 1020 1021/* 1022 * Notify a remote cpu of new work. Sends an IPI if criteria are met. 1023 */ 1024static void 1025tdq_notify(struct tdq *tdq, struct thread *td) 1026{ 1027 struct thread *ctd; 1028 int pri; 1029 int cpu; 1030 1031 if (tdq->tdq_ipipending) 1032 return; 1033 cpu = td->td_sched->ts_cpu; 1034 pri = td->td_priority; 1035 ctd = pcpu_find(cpu)->pc_curthread; 1036 if (!sched_shouldpreempt(pri, ctd->td_priority, 1)) 1037 return; 1038 if (TD_IS_IDLETHREAD(ctd)) { 1039 /* 1040 * If the MD code has an idle wakeup routine try that before 1041 * falling back to IPI. 1042 */ 1043 if (!tdq->tdq_cpu_idle || cpu_idle_wakeup(cpu)) 1044 return; 1045 } 1046 tdq->tdq_ipipending = 1; 1047 ipi_cpu(cpu, IPI_PREEMPT); 1048} 1049 1050/* 1051 * Steals load from a timeshare queue. Honors the rotating queue head 1052 * index. 1053 */ 1054static struct thread * 1055runq_steal_from(struct runq *rq, int cpu, u_char start) 1056{ 1057 struct rqbits *rqb; 1058 struct rqhead *rqh; 1059 struct thread *td, *first; 1060 int bit; 1061 int pri; 1062 int i; 1063 1064 rqb = &rq->rq_status; 1065 bit = start & (RQB_BPW -1); 1066 pri = 0; 1067 first = NULL; 1068again: 1069 for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) { 1070 if (rqb->rqb_bits[i] == 0) 1071 continue; 1072 if (bit != 0) { 1073 for (pri = bit; pri < RQB_BPW; pri++) 1074 if (rqb->rqb_bits[i] & (1ul << pri)) 1075 break; 1076 if (pri >= RQB_BPW) 1077 continue; 1078 } else 1079 pri = RQB_FFS(rqb->rqb_bits[i]); 1080 pri += (i << RQB_L2BPW); 1081 rqh = &rq->rq_queues[pri]; 1082 TAILQ_FOREACH(td, rqh, td_runq) { 1083 if (first && THREAD_CAN_MIGRATE(td) && 1084 THREAD_CAN_SCHED(td, cpu)) 1085 return (td); 1086 first = td; 1087 } 1088 } 1089 if (start != 0) { 1090 start = 0; 1091 goto again; 1092 } 1093 1094 if (first && THREAD_CAN_MIGRATE(first) && 1095 THREAD_CAN_SCHED(first, cpu)) 1096 return (first); 1097 return (NULL); 1098} 1099 1100/* 1101 * Steals load from a standard linear queue. 1102 */ 1103static struct thread * 1104runq_steal(struct runq *rq, int cpu) 1105{ 1106 struct rqhead *rqh; 1107 struct rqbits *rqb; 1108 struct thread *td; 1109 int word; 1110 int bit; 1111 1112 rqb = &rq->rq_status; 1113 for (word = 0; word < RQB_LEN; word++) { 1114 if (rqb->rqb_bits[word] == 0) 1115 continue; 1116 for (bit = 0; bit < RQB_BPW; bit++) { 1117 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) 1118 continue; 1119 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; 1120 TAILQ_FOREACH(td, rqh, td_runq) 1121 if (THREAD_CAN_MIGRATE(td) && 1122 THREAD_CAN_SCHED(td, cpu)) 1123 return (td); 1124 } 1125 } 1126 return (NULL); 1127} 1128 1129/* 1130 * Attempt to steal a thread in priority order from a thread queue. 1131 */ 1132static struct thread * 1133tdq_steal(struct tdq *tdq, int cpu) 1134{ 1135 struct thread *td; 1136 1137 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1138 if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL) 1139 return (td); 1140 if ((td = runq_steal_from(&tdq->tdq_timeshare, 1141 cpu, tdq->tdq_ridx)) != NULL) 1142 return (td); 1143 return (runq_steal(&tdq->tdq_idle, cpu)); 1144} 1145 1146/* 1147 * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the 1148 * current lock and returns with the assigned queue locked. 1149 */ 1150static inline struct tdq * 1151sched_setcpu(struct thread *td, int cpu, int flags) 1152{ 1153 1154 struct tdq *tdq; 1155 1156 THREAD_LOCK_ASSERT(td, MA_OWNED); 1157 tdq = TDQ_CPU(cpu); 1158 td->td_sched->ts_cpu = cpu; 1159 /* 1160 * If the lock matches just return the queue. 1161 */ 1162 if (td->td_lock == TDQ_LOCKPTR(tdq)) 1163 return (tdq); 1164#ifdef notyet 1165 /* 1166 * If the thread isn't running its lockptr is a 1167 * turnstile or a sleepqueue. We can just lock_set without 1168 * blocking. 1169 */ 1170 if (TD_CAN_RUN(td)) { 1171 TDQ_LOCK(tdq); 1172 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 1173 return (tdq); 1174 } 1175#endif 1176 /* 1177 * The hard case, migration, we need to block the thread first to 1178 * prevent order reversals with other cpus locks. 1179 */ 1180 spinlock_enter(); 1181 thread_lock_block(td); 1182 TDQ_LOCK(tdq); 1183 thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); 1184 spinlock_exit(); 1185 return (tdq); 1186} 1187 1188SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding"); 1189SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity"); 1190SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity"); 1191SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load"); 1192SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu"); 1193SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration"); 1194 1195static int 1196sched_pickcpu(struct thread *td, int flags) 1197{ 1198 struct cpu_group *cg, *ccg; 1199 struct td_sched *ts; 1200 struct tdq *tdq; 1201 cpuset_t mask; 1202 int cpu, pri, self; 1203 1204 self = PCPU_GET(cpuid); 1205 ts = td->td_sched; 1206 if (smp_started == 0) 1207 return (self); 1208 /* 1209 * Don't migrate a running thread from sched_switch(). 1210 */ 1211 if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td)) 1212 return (ts->ts_cpu); 1213 /* 1214 * Prefer to run interrupt threads on the processors that generate 1215 * the interrupt. 1216 */ 1217 pri = td->td_priority; 1218 if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) && 1219 curthread->td_intr_nesting_level && ts->ts_cpu != self) { 1220 SCHED_STAT_INC(pickcpu_intrbind); 1221 ts->ts_cpu = self; 1222 if (TDQ_CPU(self)->tdq_lowpri > pri) { 1223 SCHED_STAT_INC(pickcpu_affinity); 1224 return (ts->ts_cpu); 1225 } 1226 } 1227 /* 1228 * If the thread can run on the last cpu and the affinity has not 1229 * expired or it is idle run it there. 1230 */ 1231 tdq = TDQ_CPU(ts->ts_cpu); 1232 cg = tdq->tdq_cg; 1233 if (THREAD_CAN_SCHED(td, ts->ts_cpu) && 1234 tdq->tdq_lowpri >= PRI_MIN_IDLE && 1235 SCHED_AFFINITY(ts, CG_SHARE_L2)) { 1236 if (cg->cg_flags & CG_FLAG_THREAD) { 1237 CPUSET_FOREACH(cpu, cg->cg_mask) { 1238 if (TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE) 1239 break; 1240 } 1241 } else 1242 cpu = INT_MAX; 1243 if (cpu > mp_maxid) { 1244 SCHED_STAT_INC(pickcpu_idle_affinity); 1245 return (ts->ts_cpu); 1246 } 1247 } 1248 /* 1249 * Search for the last level cache CPU group in the tree. 1250 * Skip caches with expired affinity time and SMT groups. 1251 * Affinity to higher level caches will be handled less aggressively. 1252 */ 1253 for (ccg = NULL; cg != NULL; cg = cg->cg_parent) { 1254 if (cg->cg_flags & CG_FLAG_THREAD) 1255 continue; 1256 if (!SCHED_AFFINITY(ts, cg->cg_level)) 1257 continue; 1258 ccg = cg; 1259 } 1260 if (ccg != NULL) 1261 cg = ccg; 1262 cpu = -1; 1263 /* Search the group for the less loaded idle CPU we can run now. */ 1264 mask = td->td_cpuset->cs_mask; 1265 if (cg != NULL && cg != cpu_top && 1266 CPU_CMP(&cg->cg_mask, &cpu_top->cg_mask) != 0) 1267 cpu = sched_lowest(cg, mask, max(pri, PRI_MAX_TIMESHARE), 1268 INT_MAX, ts->ts_cpu); 1269 /* Search globally for the less loaded CPU we can run now. */ 1270 if (cpu == -1) 1271 cpu = sched_lowest(cpu_top, mask, pri, INT_MAX, ts->ts_cpu); 1272 /* Search globally for the less loaded CPU. */ 1273 if (cpu == -1) 1274 cpu = sched_lowest(cpu_top, mask, -1, INT_MAX, ts->ts_cpu); 1275 KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu.")); 1276 /* 1277 * Compare the lowest loaded cpu to current cpu. 1278 */ 1279 if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri && 1280 TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE && 1281 TDQ_CPU(self)->tdq_load <= TDQ_CPU(cpu)->tdq_load + 1) { 1282 SCHED_STAT_INC(pickcpu_local); 1283 cpu = self; 1284 } else 1285 SCHED_STAT_INC(pickcpu_lowest); 1286 if (cpu != ts->ts_cpu) 1287 SCHED_STAT_INC(pickcpu_migration); 1288 return (cpu); 1289} 1290#endif 1291 1292/* 1293 * Pick the highest priority task we have and return it. 1294 */ 1295static struct thread * 1296tdq_choose(struct tdq *tdq) 1297{ 1298 struct thread *td; 1299 1300 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1301 td = runq_choose(&tdq->tdq_realtime); 1302 if (td != NULL) 1303 return (td); 1304 td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); 1305 if (td != NULL) { 1306 KASSERT(td->td_priority >= PRI_MIN_BATCH, 1307 ("tdq_choose: Invalid priority on timeshare queue %d", 1308 td->td_priority)); 1309 return (td); 1310 } 1311 td = runq_choose(&tdq->tdq_idle); 1312 if (td != NULL) { 1313 KASSERT(td->td_priority >= PRI_MIN_IDLE, 1314 ("tdq_choose: Invalid priority on idle queue %d", 1315 td->td_priority)); 1316 return (td); 1317 } 1318 1319 return (NULL); 1320} 1321 1322/* 1323 * Initialize a thread queue. 1324 */ 1325static void 1326tdq_setup(struct tdq *tdq) 1327{ 1328 1329 if (bootverbose) 1330 printf("ULE: setup cpu %d\n", TDQ_ID(tdq)); 1331 runq_init(&tdq->tdq_realtime); 1332 runq_init(&tdq->tdq_timeshare); 1333 runq_init(&tdq->tdq_idle); 1334 snprintf(tdq->tdq_name, sizeof(tdq->tdq_name), 1335 "sched lock %d", (int)TDQ_ID(tdq)); 1336 mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock", 1337 MTX_SPIN | MTX_RECURSE); 1338#ifdef KTR 1339 snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname), 1340 "CPU %d load", (int)TDQ_ID(tdq)); 1341#endif 1342} 1343 1344#ifdef SMP 1345static void 1346sched_setup_smp(void) 1347{ 1348 struct tdq *tdq; 1349 int i; 1350 1351 cpu_top = smp_topo(); 1352 CPU_FOREACH(i) { 1353 tdq = TDQ_CPU(i); 1354 tdq_setup(tdq); 1355 tdq->tdq_cg = smp_topo_find(cpu_top, i); 1356 if (tdq->tdq_cg == NULL) 1357 panic("Can't find cpu group for %d\n", i); 1358 } 1359 balance_tdq = TDQ_SELF(); 1360 sched_balance(); 1361} 1362#endif 1363 1364/* 1365 * Setup the thread queues and initialize the topology based on MD 1366 * information. 1367 */ 1368static void 1369sched_setup(void *dummy) 1370{ 1371 struct tdq *tdq; 1372 1373 tdq = TDQ_SELF(); 1374#ifdef SMP 1375 sched_setup_smp(); 1376#else 1377 tdq_setup(tdq); 1378#endif 1379 1380 /* Add thread0's load since it's running. */ 1381 TDQ_LOCK(tdq); 1382 thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1383 tdq_load_add(tdq, &thread0); 1384 tdq->tdq_lowpri = thread0.td_priority; 1385 TDQ_UNLOCK(tdq); 1386} 1387 1388/* 1389 * This routine determines time constants after stathz and hz are setup. 1390 */ 1391/* ARGSUSED */ 1392static void 1393sched_initticks(void *dummy) 1394{ 1395 int incr; 1396 1397 realstathz = stathz ? stathz : hz; 1398 sched_slice = realstathz / SCHED_SLICE_DEFAULT_DIVISOR; 1399 sched_slice_min = sched_slice / SCHED_SLICE_MIN_DIVISOR; 1400 hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) / 1401 realstathz); 1402 1403 /* 1404 * tickincr is shifted out by 10 to avoid rounding errors due to 1405 * hz not being evenly divisible by stathz on all platforms. 1406 */ 1407 incr = (hz << SCHED_TICK_SHIFT) / realstathz; 1408 /* 1409 * This does not work for values of stathz that are more than 1410 * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen. 1411 */ 1412 if (incr == 0) 1413 incr = 1; 1414 tickincr = incr; 1415#ifdef SMP 1416 /* 1417 * Set the default balance interval now that we know 1418 * what realstathz is. 1419 */ 1420 balance_interval = realstathz; 1421 affinity = SCHED_AFFINITY_DEFAULT; 1422#endif 1423 if (sched_idlespinthresh < 0) 1424 sched_idlespinthresh = 2 * max(10000, 6 * hz) / realstathz; 1425} 1426 1427 1428/* 1429 * This is the core of the interactivity algorithm. Determines a score based 1430 * on past behavior. It is the ratio of sleep time to run time scaled to 1431 * a [0, 100] integer. This is the voluntary sleep time of a process, which 1432 * differs from the cpu usage because it does not account for time spent 1433 * waiting on a run-queue. Would be prettier if we had floating point. 1434 */ 1435static int 1436sched_interact_score(struct thread *td) 1437{ 1438 struct td_sched *ts; 1439 int div; 1440 1441 ts = td->td_sched; 1442 /* 1443 * The score is only needed if this is likely to be an interactive 1444 * task. Don't go through the expense of computing it if there's 1445 * no chance. 1446 */ 1447 if (sched_interact <= SCHED_INTERACT_HALF && 1448 ts->ts_runtime >= ts->ts_slptime) 1449 return (SCHED_INTERACT_HALF); 1450 1451 if (ts->ts_runtime > ts->ts_slptime) { 1452 div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF); 1453 return (SCHED_INTERACT_HALF + 1454 (SCHED_INTERACT_HALF - (ts->ts_slptime / div))); 1455 } 1456 if (ts->ts_slptime > ts->ts_runtime) { 1457 div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF); 1458 return (ts->ts_runtime / div); 1459 } 1460 /* runtime == slptime */ 1461 if (ts->ts_runtime) 1462 return (SCHED_INTERACT_HALF); 1463 1464 /* 1465 * This can happen if slptime and runtime are 0. 1466 */ 1467 return (0); 1468 1469} 1470 1471/* 1472 * Scale the scheduling priority according to the "interactivity" of this 1473 * process. 1474 */ 1475static void 1476sched_priority(struct thread *td) 1477{ 1478 int score; 1479 int pri; 1480 1481 if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE) 1482 return; 1483 /* 1484 * If the score is interactive we place the thread in the realtime 1485 * queue with a priority that is less than kernel and interrupt 1486 * priorities. These threads are not subject to nice restrictions. 1487 * 1488 * Scores greater than this are placed on the normal timeshare queue 1489 * where the priority is partially decided by the most recent cpu 1490 * utilization and the rest is decided by nice value. 1491 * 1492 * The nice value of the process has a linear effect on the calculated 1493 * score. Negative nice values make it easier for a thread to be 1494 * considered interactive. 1495 */ 1496 score = imax(0, sched_interact_score(td) + td->td_proc->p_nice); 1497 if (score < sched_interact) { 1498 pri = PRI_MIN_INTERACT; 1499 pri += ((PRI_MAX_INTERACT - PRI_MIN_INTERACT + 1) / 1500 sched_interact) * score; 1501 KASSERT(pri >= PRI_MIN_INTERACT && pri <= PRI_MAX_INTERACT, 1502 ("sched_priority: invalid interactive priority %d score %d", 1503 pri, score)); 1504 } else { 1505 pri = SCHED_PRI_MIN; 1506 if (td->td_sched->ts_ticks) 1507 pri += min(SCHED_PRI_TICKS(td->td_sched), 1508 SCHED_PRI_RANGE - 1); 1509 pri += SCHED_PRI_NICE(td->td_proc->p_nice); 1510 KASSERT(pri >= PRI_MIN_BATCH && pri <= PRI_MAX_BATCH, 1511 ("sched_priority: invalid priority %d: nice %d, " 1512 "ticks %d ftick %d ltick %d tick pri %d", 1513 pri, td->td_proc->p_nice, td->td_sched->ts_ticks, 1514 td->td_sched->ts_ftick, td->td_sched->ts_ltick, 1515 SCHED_PRI_TICKS(td->td_sched))); 1516 } 1517 sched_user_prio(td, pri); 1518 1519 return; 1520} 1521 1522/* 1523 * This routine enforces a maximum limit on the amount of scheduling history 1524 * kept. It is called after either the slptime or runtime is adjusted. This 1525 * function is ugly due to integer math. 1526 */ 1527static void 1528sched_interact_update(struct thread *td) 1529{ 1530 struct td_sched *ts; 1531 u_int sum; 1532 1533 ts = td->td_sched; 1534 sum = ts->ts_runtime + ts->ts_slptime; 1535 if (sum < SCHED_SLP_RUN_MAX) 1536 return; 1537 /* 1538 * This only happens from two places: 1539 * 1) We have added an unusual amount of run time from fork_exit. 1540 * 2) We have added an unusual amount of sleep time from sched_sleep(). 1541 */ 1542 if (sum > SCHED_SLP_RUN_MAX * 2) { 1543 if (ts->ts_runtime > ts->ts_slptime) { 1544 ts->ts_runtime = SCHED_SLP_RUN_MAX; 1545 ts->ts_slptime = 1; 1546 } else { 1547 ts->ts_slptime = SCHED_SLP_RUN_MAX; 1548 ts->ts_runtime = 1; 1549 } 1550 return; 1551 } 1552 /* 1553 * If we have exceeded by more than 1/5th then the algorithm below 1554 * will not bring us back into range. Dividing by two here forces 1555 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] 1556 */ 1557 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { 1558 ts->ts_runtime /= 2; 1559 ts->ts_slptime /= 2; 1560 return; 1561 } 1562 ts->ts_runtime = (ts->ts_runtime / 5) * 4; 1563 ts->ts_slptime = (ts->ts_slptime / 5) * 4; 1564} 1565 1566/* 1567 * Scale back the interactivity history when a child thread is created. The 1568 * history is inherited from the parent but the thread may behave totally 1569 * differently. For example, a shell spawning a compiler process. We want 1570 * to learn that the compiler is behaving badly very quickly. 1571 */ 1572static void 1573sched_interact_fork(struct thread *td) 1574{ 1575 int ratio; 1576 int sum; 1577 1578 sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime; 1579 if (sum > SCHED_SLP_RUN_FORK) { 1580 ratio = sum / SCHED_SLP_RUN_FORK; 1581 td->td_sched->ts_runtime /= ratio; 1582 td->td_sched->ts_slptime /= ratio; 1583 } 1584} 1585 1586/* 1587 * Called from proc0_init() to setup the scheduler fields. 1588 */ 1589void 1590schedinit(void) 1591{ 1592 1593 /* 1594 * Set up the scheduler specific parts of proc0. 1595 */ 1596 proc0.p_sched = NULL; /* XXX */ 1597 thread0.td_sched = &td_sched0; 1598 td_sched0.ts_ltick = ticks; 1599 td_sched0.ts_ftick = ticks; 1600 td_sched0.ts_slice = 0; 1601} 1602 1603/* 1604 * This is only somewhat accurate since given many processes of the same 1605 * priority they will switch when their slices run out, which will be 1606 * at most sched_slice stathz ticks. 1607 */ 1608int 1609sched_rr_interval(void) 1610{ 1611 1612 /* Convert sched_slice from stathz to hz. */ 1613 return (imax(1, (sched_slice * hz + realstathz / 2) / realstathz)); 1614} 1615 1616/* 1617 * Update the percent cpu tracking information when it is requested or 1618 * the total history exceeds the maximum. We keep a sliding history of 1619 * tick counts that slowly decays. This is less precise than the 4BSD 1620 * mechanism since it happens with less regular and frequent events. 1621 */ 1622static void 1623sched_pctcpu_update(struct td_sched *ts, int run) 1624{ 1625 int t = ticks; 1626 1627 if (t - ts->ts_ltick >= SCHED_TICK_TARG) { 1628 ts->ts_ticks = 0; 1629 ts->ts_ftick = t - SCHED_TICK_TARG; 1630 } else if (t - ts->ts_ftick >= SCHED_TICK_MAX) { 1631 ts->ts_ticks = (ts->ts_ticks / (ts->ts_ltick - ts->ts_ftick)) * 1632 (ts->ts_ltick - (t - SCHED_TICK_TARG)); 1633 ts->ts_ftick = t - SCHED_TICK_TARG; 1634 } 1635 if (run) 1636 ts->ts_ticks += (t - ts->ts_ltick) << SCHED_TICK_SHIFT; 1637 ts->ts_ltick = t; 1638} 1639 1640/* 1641 * Adjust the priority of a thread. Move it to the appropriate run-queue 1642 * if necessary. This is the back-end for several priority related 1643 * functions. 1644 */ 1645static void 1646sched_thread_priority(struct thread *td, u_char prio) 1647{ 1648 struct td_sched *ts; 1649 struct tdq *tdq; 1650 int oldpri; 1651 1652 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio", 1653 "prio:%d", td->td_priority, "new prio:%d", prio, 1654 KTR_ATTR_LINKED, sched_tdname(curthread)); 1655 SDT_PROBE3(sched, , , change__pri, td, td->td_proc, prio); 1656 if (td != curthread && prio < td->td_priority) { 1657 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread), 1658 "lend prio", "prio:%d", td->td_priority, "new prio:%d", 1659 prio, KTR_ATTR_LINKED, sched_tdname(td)); 1660 SDT_PROBE4(sched, , , lend__pri, td, td->td_proc, prio, 1661 curthread); 1662 } 1663 ts = td->td_sched; 1664 THREAD_LOCK_ASSERT(td, MA_OWNED); 1665 if (td->td_priority == prio) 1666 return; 1667 /* 1668 * If the priority has been elevated due to priority 1669 * propagation, we may have to move ourselves to a new 1670 * queue. This could be optimized to not re-add in some 1671 * cases. 1672 */ 1673 if (TD_ON_RUNQ(td) && prio < td->td_priority) { 1674 sched_rem(td); 1675 td->td_priority = prio; 1676 sched_add(td, SRQ_BORROWING); 1677 return; 1678 } 1679 /* 1680 * If the thread is currently running we may have to adjust the lowpri 1681 * information so other cpus are aware of our current priority. 1682 */ 1683 if (TD_IS_RUNNING(td)) { 1684 tdq = TDQ_CPU(ts->ts_cpu); 1685 oldpri = td->td_priority; 1686 td->td_priority = prio; 1687 if (prio < tdq->tdq_lowpri) 1688 tdq->tdq_lowpri = prio; 1689 else if (tdq->tdq_lowpri == oldpri) 1690 tdq_setlowpri(tdq, td); 1691 return; 1692 } 1693 td->td_priority = prio; 1694} 1695 1696/* 1697 * Update a thread's priority when it is lent another thread's 1698 * priority. 1699 */ 1700void 1701sched_lend_prio(struct thread *td, u_char prio) 1702{ 1703 1704 td->td_flags |= TDF_BORROWING; 1705 sched_thread_priority(td, prio); 1706} 1707 1708/* 1709 * Restore a thread's priority when priority propagation is 1710 * over. The prio argument is the minimum priority the thread 1711 * needs to have to satisfy other possible priority lending 1712 * requests. If the thread's regular priority is less 1713 * important than prio, the thread will keep a priority boost 1714 * of prio. 1715 */ 1716void 1717sched_unlend_prio(struct thread *td, u_char prio) 1718{ 1719 u_char base_pri; 1720 1721 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 1722 td->td_base_pri <= PRI_MAX_TIMESHARE) 1723 base_pri = td->td_user_pri; 1724 else 1725 base_pri = td->td_base_pri; 1726 if (prio >= base_pri) { 1727 td->td_flags &= ~TDF_BORROWING; 1728 sched_thread_priority(td, base_pri); 1729 } else 1730 sched_lend_prio(td, prio); 1731} 1732 1733/* 1734 * Standard entry for setting the priority to an absolute value. 1735 */ 1736void 1737sched_prio(struct thread *td, u_char prio) 1738{ 1739 u_char oldprio; 1740 1741 /* First, update the base priority. */ 1742 td->td_base_pri = prio; 1743 1744 /* 1745 * If the thread is borrowing another thread's priority, don't 1746 * ever lower the priority. 1747 */ 1748 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 1749 return; 1750 1751 /* Change the real priority. */ 1752 oldprio = td->td_priority; 1753 sched_thread_priority(td, prio); 1754 1755 /* 1756 * If the thread is on a turnstile, then let the turnstile update 1757 * its state. 1758 */ 1759 if (TD_ON_LOCK(td) && oldprio != prio) 1760 turnstile_adjust(td, oldprio); 1761} 1762 1763/* 1764 * Set the base user priority, does not effect current running priority. 1765 */ 1766void 1767sched_user_prio(struct thread *td, u_char prio) 1768{ 1769 1770 td->td_base_user_pri = prio; 1771 if (td->td_lend_user_pri <= prio) 1772 return; 1773 td->td_user_pri = prio; 1774} 1775 1776void 1777sched_lend_user_prio(struct thread *td, u_char prio) 1778{ 1779 1780 THREAD_LOCK_ASSERT(td, MA_OWNED); 1781 td->td_lend_user_pri = prio; 1782 td->td_user_pri = min(prio, td->td_base_user_pri); 1783 if (td->td_priority > td->td_user_pri) 1784 sched_prio(td, td->td_user_pri); 1785 else if (td->td_priority != td->td_user_pri) 1786 td->td_flags |= TDF_NEEDRESCHED; 1787} 1788 1789/* 1790 * Handle migration from sched_switch(). This happens only for 1791 * cpu binding. 1792 */ 1793static struct mtx * 1794sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) 1795{ 1796 struct tdq *tdn; 1797 1798 tdn = TDQ_CPU(td->td_sched->ts_cpu); 1799#ifdef SMP 1800 tdq_load_rem(tdq, td); 1801 /* 1802 * Do the lock dance required to avoid LOR. We grab an extra 1803 * spinlock nesting to prevent preemption while we're 1804 * not holding either run-queue lock. 1805 */ 1806 spinlock_enter(); 1807 thread_lock_block(td); /* This releases the lock on tdq. */ 1808 1809 /* 1810 * Acquire both run-queue locks before placing the thread on the new 1811 * run-queue to avoid deadlocks created by placing a thread with a 1812 * blocked lock on the run-queue of a remote processor. The deadlock 1813 * occurs when a third processor attempts to lock the two queues in 1814 * question while the target processor is spinning with its own 1815 * run-queue lock held while waiting for the blocked lock to clear. 1816 */ 1817 tdq_lock_pair(tdn, tdq); 1818 tdq_add(tdn, td, flags); 1819 tdq_notify(tdn, td); 1820 TDQ_UNLOCK(tdn); 1821 spinlock_exit(); 1822#endif 1823 return (TDQ_LOCKPTR(tdn)); 1824} 1825 1826/* 1827 * Variadic version of thread_lock_unblock() that does not assume td_lock 1828 * is blocked. 1829 */ 1830static inline void 1831thread_unblock_switch(struct thread *td, struct mtx *mtx) 1832{ 1833 atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock, 1834 (uintptr_t)mtx); 1835} 1836 1837/* 1838 * Switch threads. This function has to handle threads coming in while 1839 * blocked for some reason, running, or idle. It also must deal with 1840 * migrating a thread from one queue to another as running threads may 1841 * be assigned elsewhere via binding. 1842 */ 1843void 1844sched_switch(struct thread *td, struct thread *newtd, int flags) 1845{ 1846 struct tdq *tdq; 1847 struct td_sched *ts; 1848 struct mtx *mtx; 1849 int srqflag; 1850 int cpuid, preempted; 1851 1852 THREAD_LOCK_ASSERT(td, MA_OWNED); 1853 KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument")); 1854 1855 cpuid = PCPU_GET(cpuid); 1856 tdq = TDQ_CPU(cpuid); 1857 ts = td->td_sched; 1858 mtx = td->td_lock; 1859 sched_pctcpu_update(ts, 1); 1860 ts->ts_rltick = ticks; 1861 td->td_lastcpu = td->td_oncpu; 1862 td->td_oncpu = NOCPU; 1863 preempted = !(td->td_flags & TDF_SLICEEND); 1864 td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND); 1865 td->td_owepreempt = 0; 1866 if (!TD_IS_IDLETHREAD(td)) 1867 tdq->tdq_switchcnt++; 1868 /* 1869 * The lock pointer in an idle thread should never change. Reset it 1870 * to CAN_RUN as well. 1871 */ 1872 if (TD_IS_IDLETHREAD(td)) { 1873 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1874 TD_SET_CAN_RUN(td); 1875 } else if (TD_IS_RUNNING(td)) { 1876 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1877 srqflag = preempted ? 1878 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1879 SRQ_OURSELF|SRQ_YIELDING; 1880#ifdef SMP 1881 if (THREAD_CAN_MIGRATE(td) && !THREAD_CAN_SCHED(td, ts->ts_cpu)) 1882 ts->ts_cpu = sched_pickcpu(td, 0); 1883#endif 1884 if (ts->ts_cpu == cpuid) 1885 tdq_runq_add(tdq, td, srqflag); 1886 else { 1887 KASSERT(THREAD_CAN_MIGRATE(td) || 1888 (ts->ts_flags & TSF_BOUND) != 0, 1889 ("Thread %p shouldn't migrate", td)); 1890 mtx = sched_switch_migrate(tdq, td, srqflag); 1891 } 1892 } else { 1893 /* This thread must be going to sleep. */ 1894 TDQ_LOCK(tdq); 1895 mtx = thread_lock_block(td); 1896 tdq_load_rem(tdq, td); 1897 } 1898 /* 1899 * We enter here with the thread blocked and assigned to the 1900 * appropriate cpu run-queue or sleep-queue and with the current 1901 * thread-queue locked. 1902 */ 1903 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 1904 newtd = choosethread(); 1905 /* 1906 * Call the MD code to switch contexts if necessary. 1907 */ 1908 if (td != newtd) { 1909#ifdef HWPMC_HOOKS 1910 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1911 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1912#endif 1913 SDT_PROBE2(sched, , , off__cpu, newtd, newtd->td_proc); 1914 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 1915 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 1916 sched_pctcpu_update(newtd->td_sched, 0); 1917 1918#ifdef KDTRACE_HOOKS 1919 /* 1920 * If DTrace has set the active vtime enum to anything 1921 * other than INACTIVE (0), then it should have set the 1922 * function to call. 1923 */ 1924 if (dtrace_vtime_active) 1925 (*dtrace_vtime_switch_func)(newtd); 1926#endif 1927 1928 cpu_switch(td, newtd, mtx); 1929 /* 1930 * We may return from cpu_switch on a different cpu. However, 1931 * we always return with td_lock pointing to the current cpu's 1932 * run queue lock. 1933 */ 1934 cpuid = PCPU_GET(cpuid); 1935 tdq = TDQ_CPU(cpuid); 1936 lock_profile_obtain_lock_success( 1937 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 1938 1939 SDT_PROBE0(sched, , , on__cpu); 1940#ifdef HWPMC_HOOKS 1941 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1942 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1943#endif 1944 } else { 1945 thread_unblock_switch(td, mtx); 1946 SDT_PROBE0(sched, , , remain__cpu); 1947 } 1948 /* 1949 * Assert that all went well and return. 1950 */ 1951 TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED); 1952 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1953 td->td_oncpu = cpuid; 1954} 1955 1956/* 1957 * Adjust thread priorities as a result of a nice request. 1958 */ 1959void 1960sched_nice(struct proc *p, int nice) 1961{ 1962 struct thread *td; 1963 1964 PROC_LOCK_ASSERT(p, MA_OWNED); 1965 1966 p->p_nice = nice; 1967 FOREACH_THREAD_IN_PROC(p, td) { 1968 thread_lock(td); 1969 sched_priority(td); 1970 sched_prio(td, td->td_base_user_pri); 1971 thread_unlock(td); 1972 } 1973} 1974 1975/* 1976 * Record the sleep time for the interactivity scorer. 1977 */ 1978void 1979sched_sleep(struct thread *td, int prio) 1980{ 1981 1982 THREAD_LOCK_ASSERT(td, MA_OWNED); 1983 1984 td->td_slptick = ticks; 1985 if (TD_IS_SUSPENDED(td) || prio >= PSOCK) 1986 td->td_flags |= TDF_CANSWAP; 1987 if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE) 1988 return; 1989 if (static_boost == 1 && prio) 1990 sched_prio(td, prio); 1991 else if (static_boost && td->td_priority > static_boost) 1992 sched_prio(td, static_boost); 1993} 1994 1995/* 1996 * Schedule a thread to resume execution and record how long it voluntarily 1997 * slept. We also update the pctcpu, interactivity, and priority. 1998 */ 1999void 2000sched_wakeup(struct thread *td) 2001{ 2002 struct td_sched *ts; 2003 int slptick; 2004 2005 THREAD_LOCK_ASSERT(td, MA_OWNED); 2006 ts = td->td_sched; 2007 td->td_flags &= ~TDF_CANSWAP; 2008 /* 2009 * If we slept for more than a tick update our interactivity and 2010 * priority. 2011 */ 2012 slptick = td->td_slptick; 2013 td->td_slptick = 0; 2014 if (slptick && slptick != ticks) { 2015 ts->ts_slptime += (ticks - slptick) << SCHED_TICK_SHIFT; 2016 sched_interact_update(td); 2017 sched_pctcpu_update(ts, 0); 2018 } 2019 /* 2020 * Reset the slice value since we slept and advanced the round-robin. 2021 */ 2022 ts->ts_slice = 0; 2023 sched_add(td, SRQ_BORING); 2024} 2025 2026/* 2027 * Penalize the parent for creating a new child and initialize the child's 2028 * priority. 2029 */ 2030void 2031sched_fork(struct thread *td, struct thread *child) 2032{ 2033 THREAD_LOCK_ASSERT(td, MA_OWNED); 2034 sched_pctcpu_update(td->td_sched, 1); 2035 sched_fork_thread(td, child); 2036 /* 2037 * Penalize the parent and child for forking. 2038 */ 2039 sched_interact_fork(child); 2040 sched_priority(child); 2041 td->td_sched->ts_runtime += tickincr; 2042 sched_interact_update(td); 2043 sched_priority(td); 2044} 2045 2046/* 2047 * Fork a new thread, may be within the same process. 2048 */ 2049void 2050sched_fork_thread(struct thread *td, struct thread *child) 2051{ 2052 struct td_sched *ts; 2053 struct td_sched *ts2; 2054 struct tdq *tdq; 2055 2056 tdq = TDQ_SELF(); 2057 THREAD_LOCK_ASSERT(td, MA_OWNED); 2058 /* 2059 * Initialize child. 2060 */ 2061 ts = td->td_sched; 2062 ts2 = child->td_sched; 2063 child->td_lock = TDQ_LOCKPTR(tdq); 2064 child->td_cpuset = cpuset_ref(td->td_cpuset); 2065 ts2->ts_cpu = ts->ts_cpu; 2066 ts2->ts_flags = 0; 2067 /* 2068 * Grab our parents cpu estimation information. 2069 */ 2070 ts2->ts_ticks = ts->ts_ticks; 2071 ts2->ts_ltick = ts->ts_ltick; 2072 ts2->ts_ftick = ts->ts_ftick; 2073 /* 2074 * Do not inherit any borrowed priority from the parent. 2075 */ 2076 child->td_priority = child->td_base_pri; 2077 /* 2078 * And update interactivity score. 2079 */ 2080 ts2->ts_slptime = ts->ts_slptime; 2081 ts2->ts_runtime = ts->ts_runtime; 2082 /* Attempt to quickly learn interactivity. */ 2083 ts2->ts_slice = tdq_slice(tdq) - sched_slice_min; 2084#ifdef KTR 2085 bzero(ts2->ts_name, sizeof(ts2->ts_name)); 2086#endif 2087} 2088 2089/* 2090 * Adjust the priority class of a thread. 2091 */ 2092void 2093sched_class(struct thread *td, int class) 2094{ 2095 2096 THREAD_LOCK_ASSERT(td, MA_OWNED); 2097 if (td->td_pri_class == class) 2098 return; 2099 td->td_pri_class = class; 2100} 2101 2102/* 2103 * Return some of the child's priority and interactivity to the parent. 2104 */ 2105void 2106sched_exit(struct proc *p, struct thread *child) 2107{ 2108 struct thread *td; 2109 2110 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit", 2111 "prio:%d", child->td_priority); 2112 PROC_LOCK_ASSERT(p, MA_OWNED); 2113 td = FIRST_THREAD_IN_PROC(p); 2114 sched_exit_thread(td, child); 2115} 2116 2117/* 2118 * Penalize another thread for the time spent on this one. This helps to 2119 * worsen the priority and interactivity of processes which schedule batch 2120 * jobs such as make. This has little effect on the make process itself but 2121 * causes new processes spawned by it to receive worse scores immediately. 2122 */ 2123void 2124sched_exit_thread(struct thread *td, struct thread *child) 2125{ 2126 2127 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit", 2128 "prio:%d", child->td_priority); 2129 /* 2130 * Give the child's runtime to the parent without returning the 2131 * sleep time as a penalty to the parent. This causes shells that 2132 * launch expensive things to mark their children as expensive. 2133 */ 2134 thread_lock(td); 2135 td->td_sched->ts_runtime += child->td_sched->ts_runtime; 2136 sched_interact_update(td); 2137 sched_priority(td); 2138 thread_unlock(td); 2139} 2140 2141void 2142sched_preempt(struct thread *td) 2143{ 2144 struct tdq *tdq; 2145 2146 SDT_PROBE2(sched, , , surrender, td, td->td_proc); 2147 2148 thread_lock(td); 2149 tdq = TDQ_SELF(); 2150 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2151 tdq->tdq_ipipending = 0; 2152 if (td->td_priority > tdq->tdq_lowpri) { 2153 int flags; 2154 2155 flags = SW_INVOL | SW_PREEMPT; 2156 if (td->td_critnest > 1) 2157 td->td_owepreempt = 1; 2158 else if (TD_IS_IDLETHREAD(td)) 2159 mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL); 2160 else 2161 mi_switch(flags | SWT_REMOTEPREEMPT, NULL); 2162 } 2163 thread_unlock(td); 2164} 2165 2166/* 2167 * Fix priorities on return to user-space. Priorities may be elevated due 2168 * to static priorities in msleep() or similar. 2169 */ 2170void 2171sched_userret(struct thread *td) 2172{ 2173 /* 2174 * XXX we cheat slightly on the locking here to avoid locking in 2175 * the usual case. Setting td_priority here is essentially an 2176 * incomplete workaround for not setting it properly elsewhere. 2177 * Now that some interrupt handlers are threads, not setting it 2178 * properly elsewhere can clobber it in the window between setting 2179 * it here and returning to user mode, so don't waste time setting 2180 * it perfectly here. 2181 */ 2182 KASSERT((td->td_flags & TDF_BORROWING) == 0, 2183 ("thread with borrowed priority returning to userland")); 2184 if (td->td_priority != td->td_user_pri) { 2185 thread_lock(td); 2186 td->td_priority = td->td_user_pri; 2187 td->td_base_pri = td->td_user_pri; 2188 tdq_setlowpri(TDQ_SELF(), td); 2189 thread_unlock(td); 2190 } 2191} 2192 2193/* 2194 * Handle a stathz tick. This is really only relevant for timeshare 2195 * threads. 2196 */ 2197void 2198sched_clock(struct thread *td) 2199{ 2200 struct tdq *tdq; 2201 struct td_sched *ts; 2202 2203 THREAD_LOCK_ASSERT(td, MA_OWNED); 2204 tdq = TDQ_SELF(); 2205#ifdef SMP 2206 /* 2207 * We run the long term load balancer infrequently on the first cpu. 2208 */ 2209 if (balance_tdq == tdq) { 2210 if (balance_ticks && --balance_ticks == 0) 2211 sched_balance(); 2212 } 2213#endif 2214 /* 2215 * Save the old switch count so we have a record of the last ticks 2216 * activity. Initialize the new switch count based on our load. 2217 * If there is some activity seed it to reflect that. 2218 */ 2219 tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt; 2220 tdq->tdq_switchcnt = tdq->tdq_load; 2221 /* 2222 * Advance the insert index once for each tick to ensure that all 2223 * threads get a chance to run. 2224 */ 2225 if (tdq->tdq_idx == tdq->tdq_ridx) { 2226 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; 2227 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) 2228 tdq->tdq_ridx = tdq->tdq_idx; 2229 } 2230 ts = td->td_sched; 2231 sched_pctcpu_update(ts, 1); 2232 if (td->td_pri_class & PRI_FIFO_BIT) 2233 return; 2234 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) { 2235 /* 2236 * We used a tick; charge it to the thread so 2237 * that we can compute our interactivity. 2238 */ 2239 td->td_sched->ts_runtime += tickincr; 2240 sched_interact_update(td); 2241 sched_priority(td); 2242 } 2243 2244 /* 2245 * Force a context switch if the current thread has used up a full 2246 * time slice (default is 100ms). 2247 */ 2248 if (!TD_IS_IDLETHREAD(td) && ++ts->ts_slice >= tdq_slice(tdq)) { 2249 ts->ts_slice = 0; 2250 td->td_flags |= TDF_NEEDRESCHED | TDF_SLICEEND; 2251 } 2252} 2253 2254/* 2255 * Called once per hz tick. 2256 */ 2257void 2258sched_tick(int cnt) 2259{ 2260 2261} 2262 2263/* 2264 * Return whether the current CPU has runnable tasks. Used for in-kernel 2265 * cooperative idle threads. 2266 */ 2267int 2268sched_runnable(void) 2269{ 2270 struct tdq *tdq; 2271 int load; 2272 2273 load = 1; 2274 2275 tdq = TDQ_SELF(); 2276 if ((curthread->td_flags & TDF_IDLETD) != 0) { 2277 if (tdq->tdq_load > 0) 2278 goto out; 2279 } else 2280 if (tdq->tdq_load - 1 > 0) 2281 goto out; 2282 load = 0; 2283out: 2284 return (load); 2285} 2286 2287/* 2288 * Choose the highest priority thread to run. The thread is removed from 2289 * the run-queue while running however the load remains. For SMP we set 2290 * the tdq in the global idle bitmask if it idles here. 2291 */ 2292struct thread * 2293sched_choose(void) 2294{ 2295 struct thread *td; 2296 struct tdq *tdq; 2297 2298 tdq = TDQ_SELF(); 2299 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2300 td = tdq_choose(tdq); 2301 if (td) { 2302 tdq_runq_rem(tdq, td); 2303 tdq->tdq_lowpri = td->td_priority; 2304 return (td); 2305 } 2306 tdq->tdq_lowpri = PRI_MAX_IDLE; 2307 return (PCPU_GET(idlethread)); 2308} 2309 2310/* 2311 * Set owepreempt if necessary. Preemption never happens directly in ULE, 2312 * we always request it once we exit a critical section. 2313 */ 2314static inline void 2315sched_setpreempt(struct thread *td) 2316{ 2317 struct thread *ctd; 2318 int cpri; 2319 int pri; 2320 2321 THREAD_LOCK_ASSERT(curthread, MA_OWNED); 2322 2323 ctd = curthread; 2324 pri = td->td_priority; 2325 cpri = ctd->td_priority; 2326 if (pri < cpri) 2327 ctd->td_flags |= TDF_NEEDRESCHED; 2328 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) 2329 return; 2330 if (!sched_shouldpreempt(pri, cpri, 0)) 2331 return; 2332 ctd->td_owepreempt = 1; 2333} 2334 2335/* 2336 * Add a thread to a thread queue. Select the appropriate runq and add the 2337 * thread to it. This is the internal function called when the tdq is 2338 * predetermined. 2339 */ 2340void 2341tdq_add(struct tdq *tdq, struct thread *td, int flags) 2342{ 2343 2344 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2345 KASSERT((td->td_inhibitors == 0), 2346 ("sched_add: trying to run inhibited thread")); 2347 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 2348 ("sched_add: bad thread state")); 2349 KASSERT(td->td_flags & TDF_INMEM, 2350 ("sched_add: thread swapped out")); 2351 2352 if (td->td_priority < tdq->tdq_lowpri) 2353 tdq->tdq_lowpri = td->td_priority; 2354 tdq_runq_add(tdq, td, flags); 2355 tdq_load_add(tdq, td); 2356} 2357 2358/* 2359 * Select the target thread queue and add a thread to it. Request 2360 * preemption or IPI a remote processor if required. 2361 */ 2362void 2363sched_add(struct thread *td, int flags) 2364{ 2365 struct tdq *tdq; 2366#ifdef SMP 2367 int cpu; 2368#endif 2369 2370 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", 2371 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 2372 sched_tdname(curthread)); 2373 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup", 2374 KTR_ATTR_LINKED, sched_tdname(td)); 2375 SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL, 2376 flags & SRQ_PREEMPTED); 2377 THREAD_LOCK_ASSERT(td, MA_OWNED); 2378 /* 2379 * Recalculate the priority before we select the target cpu or 2380 * run-queue. 2381 */ 2382 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 2383 sched_priority(td); 2384#ifdef SMP 2385 /* 2386 * Pick the destination cpu and if it isn't ours transfer to the 2387 * target cpu. 2388 */ 2389 cpu = sched_pickcpu(td, flags); 2390 tdq = sched_setcpu(td, cpu, flags); 2391 tdq_add(tdq, td, flags); 2392 if (cpu != PCPU_GET(cpuid)) { 2393 tdq_notify(tdq, td); 2394 return; 2395 } 2396#else 2397 tdq = TDQ_SELF(); 2398 TDQ_LOCK(tdq); 2399 /* 2400 * Now that the thread is moving to the run-queue, set the lock 2401 * to the scheduler's lock. 2402 */ 2403 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 2404 tdq_add(tdq, td, flags); 2405#endif 2406 if (!(flags & SRQ_YIELDING)) 2407 sched_setpreempt(td); 2408} 2409 2410/* 2411 * Remove a thread from a run-queue without running it. This is used 2412 * when we're stealing a thread from a remote queue. Otherwise all threads 2413 * exit by calling sched_exit_thread() and sched_throw() themselves. 2414 */ 2415void 2416sched_rem(struct thread *td) 2417{ 2418 struct tdq *tdq; 2419 2420 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem", 2421 "prio:%d", td->td_priority); 2422 SDT_PROBE3(sched, , , dequeue, td, td->td_proc, NULL); 2423 tdq = TDQ_CPU(td->td_sched->ts_cpu); 2424 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2425 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2426 KASSERT(TD_ON_RUNQ(td), 2427 ("sched_rem: thread not on run queue")); 2428 tdq_runq_rem(tdq, td); 2429 tdq_load_rem(tdq, td); 2430 TD_SET_CAN_RUN(td); 2431 if (td->td_priority == tdq->tdq_lowpri) 2432 tdq_setlowpri(tdq, NULL); 2433} 2434 2435/* 2436 * Fetch cpu utilization information. Updates on demand. 2437 */ 2438fixpt_t 2439sched_pctcpu(struct thread *td) 2440{ 2441 fixpt_t pctcpu; 2442 struct td_sched *ts; 2443 2444 pctcpu = 0; 2445 ts = td->td_sched; 2446 if (ts == NULL) 2447 return (0); 2448 2449 THREAD_LOCK_ASSERT(td, MA_OWNED); 2450 sched_pctcpu_update(ts, TD_IS_RUNNING(td)); 2451 if (ts->ts_ticks) { 2452 int rtick; 2453 2454 /* How many rtick per second ? */ 2455 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); 2456 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; 2457 } 2458 2459 return (pctcpu); 2460} 2461 2462/* 2463 * Enforce affinity settings for a thread. Called after adjustments to 2464 * cpumask. 2465 */ 2466void 2467sched_affinity(struct thread *td) 2468{ 2469#ifdef SMP 2470 struct td_sched *ts; 2471 2472 THREAD_LOCK_ASSERT(td, MA_OWNED); 2473 ts = td->td_sched; 2474 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) 2475 return; 2476 if (TD_ON_RUNQ(td)) { 2477 sched_rem(td); 2478 sched_add(td, SRQ_BORING); 2479 return; 2480 } 2481 if (!TD_IS_RUNNING(td)) 2482 return; 2483 /* 2484 * Force a switch before returning to userspace. If the 2485 * target thread is not running locally send an ipi to force 2486 * the issue. 2487 */ 2488 td->td_flags |= TDF_NEEDRESCHED; 2489 if (td != curthread) 2490 ipi_cpu(ts->ts_cpu, IPI_PREEMPT); 2491#endif 2492} 2493 2494/* 2495 * Bind a thread to a target cpu. 2496 */ 2497void 2498sched_bind(struct thread *td, int cpu) 2499{ 2500 struct td_sched *ts; 2501 2502 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 2503 KASSERT(td == curthread, ("sched_bind: can only bind curthread")); 2504 ts = td->td_sched; 2505 if (ts->ts_flags & TSF_BOUND) 2506 sched_unbind(td); 2507 KASSERT(THREAD_CAN_MIGRATE(td), ("%p must be migratable", td)); 2508 ts->ts_flags |= TSF_BOUND; 2509 sched_pin(); 2510 if (PCPU_GET(cpuid) == cpu) 2511 return; 2512 ts->ts_cpu = cpu; 2513 /* When we return from mi_switch we'll be on the correct cpu. */ 2514 mi_switch(SW_VOL, NULL); 2515} 2516 2517/* 2518 * Release a bound thread. 2519 */ 2520void 2521sched_unbind(struct thread *td) 2522{ 2523 struct td_sched *ts; 2524 2525 THREAD_LOCK_ASSERT(td, MA_OWNED); 2526 KASSERT(td == curthread, ("sched_unbind: can only bind curthread")); 2527 ts = td->td_sched; 2528 if ((ts->ts_flags & TSF_BOUND) == 0) 2529 return; 2530 ts->ts_flags &= ~TSF_BOUND; 2531 sched_unpin(); 2532} 2533 2534int 2535sched_is_bound(struct thread *td) 2536{ 2537 THREAD_LOCK_ASSERT(td, MA_OWNED); 2538 return (td->td_sched->ts_flags & TSF_BOUND); 2539} 2540 2541/* 2542 * Basic yield call. 2543 */ 2544void 2545sched_relinquish(struct thread *td) 2546{ 2547 thread_lock(td); 2548 mi_switch(SW_VOL | SWT_RELINQUISH, NULL); 2549 thread_unlock(td); 2550} 2551 2552/* 2553 * Return the total system load. 2554 */ 2555int 2556sched_load(void) 2557{ 2558#ifdef SMP 2559 int total; 2560 int i; 2561 2562 total = 0; 2563 CPU_FOREACH(i) 2564 total += TDQ_CPU(i)->tdq_sysload; 2565 return (total); 2566#else 2567 return (TDQ_SELF()->tdq_sysload); 2568#endif 2569} 2570 2571int 2572sched_sizeof_proc(void) 2573{ 2574 return (sizeof(struct proc)); 2575} 2576 2577int 2578sched_sizeof_thread(void) 2579{ 2580 return (sizeof(struct thread) + sizeof(struct td_sched)); 2581} 2582 2583#ifdef SMP 2584#define TDQ_IDLESPIN(tdq) \ 2585 ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0) 2586#else 2587#define TDQ_IDLESPIN(tdq) 1 2588#endif 2589 2590/* 2591 * The actual idle process. 2592 */ 2593void 2594sched_idletd(void *dummy) 2595{ 2596 struct thread *td; 2597 struct tdq *tdq; 2598 int oldswitchcnt, switchcnt; 2599 int i; 2600 2601 mtx_assert(&Giant, MA_NOTOWNED); 2602 td = curthread; 2603 tdq = TDQ_SELF(); 2604 THREAD_NO_SLEEPING(); 2605 oldswitchcnt = -1; 2606 for (;;) { 2607 if (tdq->tdq_load) { 2608 thread_lock(td); 2609 mi_switch(SW_VOL | SWT_IDLE, NULL); 2610 thread_unlock(td); 2611 } 2612 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2613#ifdef SMP 2614 if (switchcnt != oldswitchcnt) { 2615 oldswitchcnt = switchcnt; 2616 if (tdq_idled(tdq) == 0) 2617 continue; 2618 } 2619 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2620#else 2621 oldswitchcnt = switchcnt; 2622#endif 2623 /* 2624 * If we're switching very frequently, spin while checking 2625 * for load rather than entering a low power state that 2626 * may require an IPI. However, don't do any busy 2627 * loops while on SMT machines as this simply steals 2628 * cycles from cores doing useful work. 2629 */ 2630 if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) { 2631 for (i = 0; i < sched_idlespins; i++) { 2632 if (tdq->tdq_load) 2633 break; 2634 cpu_spinwait(); 2635 } 2636 } 2637 2638 /* If there was context switch during spin, restart it. */ 2639 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2640 if (tdq->tdq_load != 0 || switchcnt != oldswitchcnt) 2641 continue; 2642 2643 /* Run main MD idle handler. */ 2644 tdq->tdq_cpu_idle = 1; 2645 cpu_idle(switchcnt * 4 > sched_idlespinthresh); 2646 tdq->tdq_cpu_idle = 0; 2647 2648 /* 2649 * Account thread-less hardware interrupts and 2650 * other wakeup reasons equal to context switches. 2651 */ 2652 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2653 if (switchcnt != oldswitchcnt) 2654 continue; 2655 tdq->tdq_switchcnt++; 2656 oldswitchcnt++; 2657 } 2658} 2659 2660/* 2661 * A CPU is entering for the first time or a thread is exiting. 2662 */ 2663void 2664sched_throw(struct thread *td) 2665{ 2666 struct thread *newtd; 2667 struct tdq *tdq; 2668 2669 tdq = TDQ_SELF(); 2670 if (td == NULL) { 2671 /* Correct spinlock nesting and acquire the correct lock. */ 2672 TDQ_LOCK(tdq); 2673 spinlock_exit(); 2674 PCPU_SET(switchtime, cpu_ticks()); 2675 PCPU_SET(switchticks, ticks); 2676 } else { 2677 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2678 tdq_load_rem(tdq, td); 2679 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 2680 } 2681 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 2682 newtd = choosethread(); 2683 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 2684 cpu_throw(td, newtd); /* doesn't return */ 2685} 2686 2687/* 2688 * This is called from fork_exit(). Just acquire the correct locks and 2689 * let fork do the rest of the work. 2690 */ 2691void 2692sched_fork_exit(struct thread *td) 2693{ 2694 struct td_sched *ts; 2695 struct tdq *tdq; 2696 int cpuid; 2697 2698 /* 2699 * Finish setting up thread glue so that it begins execution in a 2700 * non-nested critical section with the scheduler lock held. 2701 */ 2702 cpuid = PCPU_GET(cpuid); 2703 tdq = TDQ_CPU(cpuid); 2704 ts = td->td_sched; 2705 if (TD_IS_IDLETHREAD(td)) 2706 td->td_lock = TDQ_LOCKPTR(tdq); 2707 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2708 td->td_oncpu = cpuid; 2709 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 2710 lock_profile_obtain_lock_success( 2711 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 2712} 2713 2714/* 2715 * Create on first use to catch odd startup conditons. 2716 */ 2717char * 2718sched_tdname(struct thread *td) 2719{ 2720#ifdef KTR 2721 struct td_sched *ts; 2722 2723 ts = td->td_sched; 2724 if (ts->ts_name[0] == '\0') 2725 snprintf(ts->ts_name, sizeof(ts->ts_name), 2726 "%s tid %d", td->td_name, td->td_tid); 2727 return (ts->ts_name); 2728#else 2729 return (td->td_name); 2730#endif 2731} 2732 2733#ifdef KTR 2734void 2735sched_clear_tdname(struct thread *td) 2736{ 2737 struct td_sched *ts; 2738 2739 ts = td->td_sched; 2740 ts->ts_name[0] = '\0'; 2741} 2742#endif 2743 2744#ifdef SMP 2745 2746/* 2747 * Build the CPU topology dump string. Is recursively called to collect 2748 * the topology tree. 2749 */ 2750static int 2751sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg, 2752 int indent) 2753{ 2754 char cpusetbuf[CPUSETBUFSIZ]; 2755 int i, first; 2756 2757 sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent, 2758 "", 1 + indent / 2, cg->cg_level); 2759 sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"%s\">", indent, "", 2760 cg->cg_count, cpusetobj_strprint(cpusetbuf, &cg->cg_mask)); 2761 first = TRUE; 2762 for (i = 0; i < MAXCPU; i++) { 2763 if (CPU_ISSET(i, &cg->cg_mask)) { 2764 if (!first) 2765 sbuf_printf(sb, ", "); 2766 else 2767 first = FALSE; 2768 sbuf_printf(sb, "%d", i); 2769 } 2770 } 2771 sbuf_printf(sb, "</cpu>\n"); 2772 2773 if (cg->cg_flags != 0) { 2774 sbuf_printf(sb, "%*s <flags>", indent, ""); 2775 if ((cg->cg_flags & CG_FLAG_HTT) != 0) 2776 sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>"); 2777 if ((cg->cg_flags & CG_FLAG_THREAD) != 0) 2778 sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>"); 2779 if ((cg->cg_flags & CG_FLAG_SMT) != 0) 2780 sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>"); 2781 sbuf_printf(sb, "</flags>\n"); 2782 } 2783 2784 if (cg->cg_children > 0) { 2785 sbuf_printf(sb, "%*s <children>\n", indent, ""); 2786 for (i = 0; i < cg->cg_children; i++) 2787 sysctl_kern_sched_topology_spec_internal(sb, 2788 &cg->cg_child[i], indent+2); 2789 sbuf_printf(sb, "%*s </children>\n", indent, ""); 2790 } 2791 sbuf_printf(sb, "%*s</group>\n", indent, ""); 2792 return (0); 2793} 2794 2795/* 2796 * Sysctl handler for retrieving topology dump. It's a wrapper for 2797 * the recursive sysctl_kern_smp_topology_spec_internal(). 2798 */ 2799static int 2800sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS) 2801{ 2802 struct sbuf *topo; 2803 int err; 2804 2805 KASSERT(cpu_top != NULL, ("cpu_top isn't initialized")); 2806 2807 topo = sbuf_new(NULL, NULL, 500, SBUF_AUTOEXTEND); 2808 if (topo == NULL) 2809 return (ENOMEM); 2810 2811 sbuf_printf(topo, "<groups>\n"); 2812 err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1); 2813 sbuf_printf(topo, "</groups>\n"); 2814 2815 if (err == 0) { 2816 sbuf_finish(topo); 2817 err = SYSCTL_OUT(req, sbuf_data(topo), sbuf_len(topo)); 2818 } 2819 sbuf_delete(topo); 2820 return (err); 2821} 2822 2823#endif 2824 2825static int 2826sysctl_kern_quantum(SYSCTL_HANDLER_ARGS) 2827{ 2828 int error, new_val, period; 2829 2830 period = 1000000 / realstathz; 2831 new_val = period * sched_slice; 2832 error = sysctl_handle_int(oidp, &new_val, 0, req); 2833 if (error != 0 || req->newptr == NULL) 2834 return (error); 2835 if (new_val <= 0) 2836 return (EINVAL); 2837 sched_slice = imax(1, (new_val + period / 2) / period); 2838 sched_slice_min = sched_slice / SCHED_SLICE_MIN_DIVISOR; 2839 hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) / 2840 realstathz); 2841 return (0); 2842} 2843 2844SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); 2845SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0, 2846 "Scheduler name"); 2847SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW, 2848 NULL, 0, sysctl_kern_quantum, "I", 2849 "Quantum for timeshare threads in microseconds"); 2850SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 2851 "Quantum for timeshare threads in stathz ticks"); 2852SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, 2853 "Interactivity score threshold"); 2854SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, 2855 &preempt_thresh, 0, 2856 "Maximal (lowest) priority for preemption"); 2857SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 0, 2858 "Assign static kernel priorities to sleeping threads"); 2859SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 0, 2860 "Number of times idle thread will spin waiting for new work"); 2861SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW, 2862 &sched_idlespinthresh, 0, 2863 "Threshold before we will permit idle thread spinning"); 2864#ifdef SMP 2865SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0, 2866 "Number of hz ticks to keep thread affinity for"); 2867SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, 2868 "Enables the long-term load balancer"); 2869SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW, 2870 &balance_interval, 0, 2871 "Average period in stathz ticks to run the long-term balancer"); 2872SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0, 2873 "Attempts to steal work from other cores before idling"); 2874SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0, 2875 "Minimum load on remote CPU before we'll steal"); 2876SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING | 2877 CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A", 2878 "XML dump of detected CPU topology"); 2879#endif 2880 2881/* ps compat. All cpu percentages from ULE are weighted. */ 2882static int ccpu = 0; 2883SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 2884