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("$FreeBSD$"); 40 41 #include "opt_hwpmc_hooks.h" 42 #include "opt_sched.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/kdb.h> 47 #include <sys/kernel.h> 48 #include <sys/ktr.h> 49 #include <sys/lock.h> 50 #include <sys/mutex.h> 51 #include <sys/proc.h> 52 #include <sys/resource.h> 53 #include <sys/resourcevar.h> 54 #include <sys/sched.h> 55 #include <sys/smp.h> 56 #include <sys/sx.h> 57 #include <sys/sysctl.h> 58 #include <sys/sysproto.h> 59 #include <sys/turnstile.h> 60 #include <sys/umtx.h> 61 #include <sys/vmmeter.h> 62 #ifdef KTRACE 63 #include <sys/uio.h> 64 #include <sys/ktrace.h> 65 #endif 66 67 #ifdef HWPMC_HOOKS 68 #include <sys/pmckern.h> 69 #endif 70 71 #include <machine/cpu.h> 72 #include <machine/smp.h> 73 74 #if !defined(__i386__) && !defined(__amd64__) && !defined(__powerpc__) && !defined(__arm__) 75 #error "This architecture is not currently compatible with ULE" 76 #endif 77 78 #define KTR_ULE 0 79 80 /* 81 * Thread scheduler specific section. All fields are protected 82 * by the thread lock. 83 */ 84 struct td_sched { 85 TAILQ_ENTRY(td_sched) ts_procq; /* Run queue. */ 86 struct thread *ts_thread; /* Active associated thread. */ 87 struct runq *ts_runq; /* Run-queue we're queued on. */ 88 short ts_flags; /* TSF_* flags. */ 89 u_char ts_rqindex; /* Run queue index. */ 90 u_char ts_cpu; /* CPU that we have affinity for. */ 91 int ts_slice; /* Ticks of slice remaining. */ 92 u_int ts_slptime; /* Number of ticks we vol. slept */ 93 u_int ts_runtime; /* Number of ticks we were running */ 94 /* The following variables are only used for pctcpu calculation */ 95 int ts_ltick; /* Last tick that we were running on */ 96 int ts_ftick; /* First tick that we were running on */ 97 int ts_ticks; /* Tick count */ 98 #ifdef SMP 99 int ts_rltick; /* Real last tick, for affinity. */ 100 #endif 101 }; 102 /* flags kept in ts_flags */ 103 #define TSF_BOUND 0x0001 /* Thread can not migrate. */ 104 #define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */ 105 106 static struct td_sched td_sched0; 107 108 /* 109 * Cpu percentage computation macros and defines. 110 * 111 * SCHED_TICK_SECS: Number of seconds to average the cpu usage across. 112 * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across. 113 * SCHED_TICK_MAX: Maximum number of ticks before scaling back. 114 * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results. 115 * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count. 116 * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks. 117 */ 118 #define SCHED_TICK_SECS 10 119 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS) 120 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz) 121 #define SCHED_TICK_SHIFT 10 122 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT) 123 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz)) 124 125 /* 126 * These macros determine priorities for non-interactive threads. They are 127 * assigned a priority based on their recent cpu utilization as expressed 128 * by the ratio of ticks to the tick total. NHALF priorities at the start 129 * and end of the MIN to MAX timeshare range are only reachable with negative 130 * or positive nice respectively. 131 * 132 * PRI_RANGE: Priority range for utilization dependent priorities. 133 * PRI_NRESV: Number of nice values. 134 * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total. 135 * PRI_NICE: Determines the part of the priority inherited from nice. 136 */ 137 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN) 138 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) 139 #define SCHED_PRI_MIN (PRI_MIN_TIMESHARE + SCHED_PRI_NHALF) 140 #define SCHED_PRI_MAX (PRI_MAX_TIMESHARE - SCHED_PRI_NHALF) 141 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN) 142 #define SCHED_PRI_TICKS(ts) \ 143 (SCHED_TICK_HZ((ts)) / \ 144 (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE)) 145 #define SCHED_PRI_NICE(nice) (nice) 146 147 /* 148 * These determine the interactivity of a process. Interactivity differs from 149 * cpu utilization in that it expresses the voluntary time slept vs time ran 150 * while cpu utilization includes all time not running. This more accurately 151 * models the intent of the thread. 152 * 153 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 154 * before throttling back. 155 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. 156 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 157 * INTERACT_THRESH: Threshhold for placement on the current runq. 158 */ 159 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT) 160 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT) 161 #define SCHED_INTERACT_MAX (100) 162 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 163 #define SCHED_INTERACT_THRESH (30) 164 165 /* 166 * tickincr: Converts a stathz tick into a hz domain scaled by 167 * the shift factor. Without the shift the error rate 168 * due to rounding would be unacceptably high. 169 * realstathz: stathz is sometimes 0 and run off of hz. 170 * sched_slice: Runtime of each thread before rescheduling. 171 * preempt_thresh: Priority threshold for preemption and remote IPIs. 172 */ 173 static int sched_interact = SCHED_INTERACT_THRESH; 174 static int realstathz; 175 static int tickincr; 176 static int sched_slice; 177 #ifdef PREEMPTION 178 #ifdef FULL_PREEMPTION 179 static int preempt_thresh = PRI_MAX_IDLE; 180 #else 181 static int preempt_thresh = PRI_MIN_KERN; 182 #endif 183 #else 184 static int preempt_thresh = 0; 185 #endif 186 187 /* 188 * tdq - per processor runqs and statistics. All fields are protected by the 189 * tdq_lock. The load and lowpri may be accessed without to avoid excess 190 * locking in sched_pickcpu(); 191 */ 192 struct tdq { 193 struct mtx *tdq_lock; /* Pointer to group lock. */ 194 struct runq tdq_realtime; /* real-time run queue. */ 195 struct runq tdq_timeshare; /* timeshare run queue. */ 196 struct runq tdq_idle; /* Queue of IDLE threads. */ 197 int tdq_load; /* Aggregate load. */ 198 u_char tdq_idx; /* Current insert index. */ 199 u_char tdq_ridx; /* Current removal index. */ 200 #ifdef SMP 201 u_char tdq_lowpri; /* Lowest priority thread. */ 202 int tdq_transferable; /* Transferable thread count. */ 203 LIST_ENTRY(tdq) tdq_siblings; /* Next in tdq group. */ 204 struct tdq_group *tdq_group; /* Our processor group. */ 205 #else 206 int tdq_sysload; /* For loadavg, !ITHD load. */ 207 #endif 208 } __aligned(64); 209 210 211 #ifdef SMP 212 /* 213 * tdq groups are groups of processors which can cheaply share threads. When 214 * one processor in the group goes idle it will check the runqs of the other 215 * processors in its group prior to halting and waiting for an interrupt. 216 * These groups are suitable for SMT (Symetric Multi-Threading) and not NUMA. 217 * In a numa environment we'd want an idle bitmap per group and a two tiered 218 * load balancer. 219 */ 220 struct tdq_group { 221 struct mtx tdg_lock; /* Protects all fields below. */ 222 int tdg_cpus; /* Count of CPUs in this tdq group. */ 223 cpumask_t tdg_cpumask; /* Mask of cpus in this group. */ 224 cpumask_t tdg_idlemask; /* Idle cpus in this group. */ 225 cpumask_t tdg_mask; /* Bit mask for first cpu. */ 226 int tdg_load; /* Total load of this group. */ 227 int tdg_transferable; /* Transferable load of this group. */ 228 LIST_HEAD(, tdq) tdg_members; /* Linked list of all members. */ 229 char tdg_name[16]; /* lock name. */ 230 } __aligned(64); 231 232 #define SCHED_AFFINITY_DEFAULT (max(1, hz / 300)) 233 #define SCHED_AFFINITY(ts) ((ts)->ts_rltick > ticks - affinity) 234 235 /* 236 * Run-time tunables. 237 */ 238 static int rebalance = 1; 239 static int balance_interval = 128; /* Default set in sched_initticks(). */ 240 static int pick_pri = 1; 241 static int affinity; 242 static int tryself = 1; 243 static int steal_htt = 1; 244 static int steal_idle = 1; 245 static int steal_thresh = 2; 246 static int topology = 0; 247 248 /* 249 * One thread queue per processor. 250 */ 251 static volatile cpumask_t tdq_idle; 252 static int tdg_maxid; 253 static struct tdq tdq_cpu[MAXCPU]; 254 static struct tdq_group tdq_groups[MAXCPU]; 255 static struct tdq *balance_tdq; 256 static int balance_group_ticks; 257 static int balance_ticks; 258 259 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)]) 260 #define TDQ_CPU(x) (&tdq_cpu[(x)]) 261 #define TDQ_ID(x) ((int)((x) - tdq_cpu)) 262 #define TDQ_GROUP(x) (&tdq_groups[(x)]) 263 #define TDG_ID(x) ((int)((x) - tdq_groups)) 264 #else /* !SMP */ 265 static struct tdq tdq_cpu; 266 static struct mtx tdq_lock; 267 268 #define TDQ_ID(x) (0) 269 #define TDQ_SELF() (&tdq_cpu) 270 #define TDQ_CPU(x) (&tdq_cpu) 271 #endif 272 273 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type)) 274 #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t))) 275 #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f)) 276 #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t))) 277 #define TDQ_LOCKPTR(t) ((t)->tdq_lock) 278 279 static void sched_priority(struct thread *); 280 static void sched_thread_priority(struct thread *, u_char); 281 static int sched_interact_score(struct thread *); 282 static void sched_interact_update(struct thread *); 283 static void sched_interact_fork(struct thread *); 284 static void sched_pctcpu_update(struct td_sched *); 285 286 /* Operations on per processor queues */ 287 static struct td_sched * tdq_choose(struct tdq *); 288 static void tdq_setup(struct tdq *); 289 static void tdq_load_add(struct tdq *, struct td_sched *); 290 static void tdq_load_rem(struct tdq *, struct td_sched *); 291 static __inline void tdq_runq_add(struct tdq *, struct td_sched *, int); 292 static __inline void tdq_runq_rem(struct tdq *, struct td_sched *); 293 void tdq_print(int cpu); 294 static void runq_print(struct runq *rq); 295 static void tdq_add(struct tdq *, struct thread *, int); 296 #ifdef SMP 297 static void tdq_move(struct tdq *, struct tdq *); 298 static int tdq_idled(struct tdq *); 299 static void tdq_notify(struct td_sched *); 300 static struct td_sched *tdq_steal(struct tdq *); 301 static struct td_sched *runq_steal(struct runq *); 302 static int sched_pickcpu(struct td_sched *, int); 303 static void sched_balance(void); 304 static void sched_balance_groups(void); 305 static void sched_balance_group(struct tdq_group *); 306 static void sched_balance_pair(struct tdq *, struct tdq *); 307 static inline struct tdq *sched_setcpu(struct td_sched *, int, int); 308 static inline struct mtx *thread_block_switch(struct thread *); 309 static inline void thread_unblock_switch(struct thread *, struct mtx *); 310 static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int); 311 312 #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0) 313 #endif 314 315 static void sched_setup(void *dummy); 316 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL) 317 318 static void sched_initticks(void *dummy); 319 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, NULL) 320 321 /* 322 * Print the threads waiting on a run-queue. 323 */ 324 static void 325 runq_print(struct runq *rq) 326 { 327 struct rqhead *rqh; 328 struct td_sched *ts; 329 int pri; 330 int j; 331 int i; 332 333 for (i = 0; i < RQB_LEN; i++) { 334 printf("\t\trunq bits %d 0x%zx\n", 335 i, rq->rq_status.rqb_bits[i]); 336 for (j = 0; j < RQB_BPW; j++) 337 if (rq->rq_status.rqb_bits[i] & (1ul << j)) { 338 pri = j + (i << RQB_L2BPW); 339 rqh = &rq->rq_queues[pri]; 340 TAILQ_FOREACH(ts, rqh, ts_procq) { 341 printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n", 342 ts->ts_thread, ts->ts_thread->td_proc->p_comm, ts->ts_thread->td_priority, ts->ts_rqindex, pri); 343 } 344 } 345 } 346 } 347 348 /* 349 * Print the status of a per-cpu thread queue. Should be a ddb show cmd. 350 */ 351 void 352 tdq_print(int cpu) 353 { 354 struct tdq *tdq; 355 356 tdq = TDQ_CPU(cpu); 357 358 printf("tdq %d:\n", TDQ_ID(tdq)); 359 printf("\tlockptr %p\n", TDQ_LOCKPTR(tdq)); 360 printf("\tload: %d\n", tdq->tdq_load); 361 printf("\ttimeshare idx: %d\n", tdq->tdq_idx); 362 printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx); 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 #ifdef SMP 370 printf("\tload transferable: %d\n", tdq->tdq_transferable); 371 printf("\tlowest priority: %d\n", tdq->tdq_lowpri); 372 printf("\tgroup: %d\n", TDG_ID(tdq->tdq_group)); 373 printf("\tLock name: %s\n", tdq->tdq_group->tdg_name); 374 #endif 375 } 376 377 #define TS_RQ_PPQ (((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS) 378 /* 379 * Add a thread to the actual run-queue. Keeps transferable counts up to 380 * date with what is actually on the run-queue. Selects the correct 381 * queue position for timeshare threads. 382 */ 383 static __inline void 384 tdq_runq_add(struct tdq *tdq, struct td_sched *ts, int flags) 385 { 386 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 387 THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); 388 #ifdef SMP 389 if (THREAD_CAN_MIGRATE(ts->ts_thread)) { 390 tdq->tdq_transferable++; 391 tdq->tdq_group->tdg_transferable++; 392 ts->ts_flags |= TSF_XFERABLE; 393 } 394 #endif 395 if (ts->ts_runq == &tdq->tdq_timeshare) { 396 u_char pri; 397 398 pri = ts->ts_thread->td_priority; 399 KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE, 400 ("Invalid priority %d on timeshare runq", pri)); 401 /* 402 * This queue contains only priorities between MIN and MAX 403 * realtime. Use the whole queue to represent these values. 404 */ 405 if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) { 406 pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ; 407 pri = (pri + tdq->tdq_idx) % RQ_NQS; 408 /* 409 * This effectively shortens the queue by one so we 410 * can have a one slot difference between idx and 411 * ridx while we wait for threads to drain. 412 */ 413 if (tdq->tdq_ridx != tdq->tdq_idx && 414 pri == tdq->tdq_ridx) 415 pri = (unsigned char)(pri - 1) % RQ_NQS; 416 } else 417 pri = tdq->tdq_ridx; 418 runq_add_pri(ts->ts_runq, ts, pri, flags); 419 } else 420 runq_add(ts->ts_runq, ts, flags); 421 } 422 423 /* 424 * Remove a thread from a run-queue. This typically happens when a thread 425 * is selected to run. Running threads are not on the queue and the 426 * transferable count does not reflect them. 427 */ 428 static __inline void 429 tdq_runq_rem(struct tdq *tdq, struct td_sched *ts) 430 { 431 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 432 KASSERT(ts->ts_runq != NULL, 433 ("tdq_runq_remove: thread %p null ts_runq", ts->ts_thread)); 434 #ifdef SMP 435 if (ts->ts_flags & TSF_XFERABLE) { 436 tdq->tdq_transferable--; 437 tdq->tdq_group->tdg_transferable--; 438 ts->ts_flags &= ~TSF_XFERABLE; 439 } 440 #endif 441 if (ts->ts_runq == &tdq->tdq_timeshare) { 442 if (tdq->tdq_idx != tdq->tdq_ridx) 443 runq_remove_idx(ts->ts_runq, ts, &tdq->tdq_ridx); 444 else 445 runq_remove_idx(ts->ts_runq, ts, NULL); 446 /* 447 * For timeshare threads we update the priority here so 448 * the priority reflects the time we've been sleeping. 449 */ 450 ts->ts_ltick = ticks; 451 sched_pctcpu_update(ts); 452 sched_priority(ts->ts_thread); 453 } else 454 runq_remove(ts->ts_runq, ts); 455 } 456 457 /* 458 * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load 459 * for this thread to the referenced thread queue. 460 */ 461 static void 462 tdq_load_add(struct tdq *tdq, struct td_sched *ts) 463 { 464 int class; 465 466 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 467 THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); 468 class = PRI_BASE(ts->ts_thread->td_pri_class); 469 tdq->tdq_load++; 470 CTR2(KTR_SCHED, "cpu %d load: %d", TDQ_ID(tdq), tdq->tdq_load); 471 if (class != PRI_ITHD && 472 (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0) 473 #ifdef SMP 474 tdq->tdq_group->tdg_load++; 475 #else 476 tdq->tdq_sysload++; 477 #endif 478 } 479 480 /* 481 * Remove the load from a thread that is transitioning to a sleep state or 482 * exiting. 483 */ 484 static void 485 tdq_load_rem(struct tdq *tdq, struct td_sched *ts) 486 { 487 int class; 488 489 THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); 490 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 491 class = PRI_BASE(ts->ts_thread->td_pri_class); 492 if (class != PRI_ITHD && 493 (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0) 494 #ifdef SMP 495 tdq->tdq_group->tdg_load--; 496 #else 497 tdq->tdq_sysload--; 498 #endif 499 KASSERT(tdq->tdq_load != 0, 500 ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq))); 501 tdq->tdq_load--; 502 CTR1(KTR_SCHED, "load: %d", tdq->tdq_load); 503 ts->ts_runq = NULL; 504 } 505 506 #ifdef SMP 507 /* 508 * sched_balance is a simple CPU load balancing algorithm. It operates by 509 * finding the least loaded and most loaded cpu and equalizing their load 510 * by migrating some processes. 511 * 512 * Dealing only with two CPUs at a time has two advantages. Firstly, most 513 * installations will only have 2 cpus. Secondly, load balancing too much at 514 * once can have an unpleasant effect on the system. The scheduler rarely has 515 * enough information to make perfect decisions. So this algorithm chooses 516 * simplicity and more gradual effects on load in larger systems. 517 * 518 */ 519 static void 520 sched_balance() 521 { 522 struct tdq_group *high; 523 struct tdq_group *low; 524 struct tdq_group *tdg; 525 struct tdq *tdq; 526 int cnt; 527 int i; 528 529 /* 530 * Select a random time between .5 * balance_interval and 531 * 1.5 * balance_interval. 532 */ 533 balance_ticks = max(balance_interval / 2, 1); 534 balance_ticks += random() % balance_interval; 535 if (smp_started == 0 || rebalance == 0) 536 return; 537 tdq = TDQ_SELF(); 538 TDQ_UNLOCK(tdq); 539 low = high = NULL; 540 i = random() % (tdg_maxid + 1); 541 for (cnt = 0; cnt <= tdg_maxid; cnt++) { 542 tdg = TDQ_GROUP(i); 543 /* 544 * Find the CPU with the highest load that has some 545 * threads to transfer. 546 */ 547 if ((high == NULL || tdg->tdg_load > high->tdg_load) 548 && tdg->tdg_transferable) 549 high = tdg; 550 if (low == NULL || tdg->tdg_load < low->tdg_load) 551 low = tdg; 552 if (++i > tdg_maxid) 553 i = 0; 554 } 555 if (low != NULL && high != NULL && high != low) 556 sched_balance_pair(LIST_FIRST(&high->tdg_members), 557 LIST_FIRST(&low->tdg_members)); 558 TDQ_LOCK(tdq); 559 } 560 561 /* 562 * Balance load between CPUs in a group. Will only migrate within the group. 563 */ 564 static void 565 sched_balance_groups() 566 { 567 struct tdq *tdq; 568 int i; 569 570 /* 571 * Select a random time between .5 * balance_interval and 572 * 1.5 * balance_interval. 573 */ 574 balance_group_ticks = max(balance_interval / 2, 1); 575 balance_group_ticks += random() % balance_interval; 576 if (smp_started == 0 || rebalance == 0) 577 return; 578 tdq = TDQ_SELF(); 579 TDQ_UNLOCK(tdq); 580 for (i = 0; i <= tdg_maxid; i++) 581 sched_balance_group(TDQ_GROUP(i)); 582 TDQ_LOCK(tdq); 583 } 584 585 /* 586 * Finds the greatest imbalance between two tdqs in a group. 587 */ 588 static void 589 sched_balance_group(struct tdq_group *tdg) 590 { 591 struct tdq *tdq; 592 struct tdq *high; 593 struct tdq *low; 594 int load; 595 596 if (tdg->tdg_transferable == 0) 597 return; 598 low = NULL; 599 high = NULL; 600 LIST_FOREACH(tdq, &tdg->tdg_members, tdq_siblings) { 601 load = tdq->tdq_load; 602 if (high == NULL || load > high->tdq_load) 603 high = tdq; 604 if (low == NULL || load < low->tdq_load) 605 low = tdq; 606 } 607 if (high != NULL && low != NULL && high != low) 608 sched_balance_pair(high, low); 609 } 610 611 /* 612 * Lock two thread queues using their address to maintain lock order. 613 */ 614 static void 615 tdq_lock_pair(struct tdq *one, struct tdq *two) 616 { 617 if (one < two) { 618 TDQ_LOCK(one); 619 TDQ_LOCK_FLAGS(two, MTX_DUPOK); 620 } else { 621 TDQ_LOCK(two); 622 TDQ_LOCK_FLAGS(one, MTX_DUPOK); 623 } 624 } 625 626 /* 627 * Unlock two thread queues. Order is not important here. 628 */ 629 static void 630 tdq_unlock_pair(struct tdq *one, struct tdq *two) 631 { 632 TDQ_UNLOCK(one); 633 TDQ_UNLOCK(two); 634 } 635 636 /* 637 * Transfer load between two imbalanced thread queues. 638 */ 639 static void 640 sched_balance_pair(struct tdq *high, struct tdq *low) 641 { 642 int transferable; 643 int high_load; 644 int low_load; 645 int move; 646 int diff; 647 int i; 648 649 tdq_lock_pair(high, low); 650 /* 651 * If we're transfering within a group we have to use this specific 652 * tdq's transferable count, otherwise we can steal from other members 653 * of the group. 654 */ 655 if (high->tdq_group == low->tdq_group) { 656 transferable = high->tdq_transferable; 657 high_load = high->tdq_load; 658 low_load = low->tdq_load; 659 } else { 660 transferable = high->tdq_group->tdg_transferable; 661 high_load = high->tdq_group->tdg_load; 662 low_load = low->tdq_group->tdg_load; 663 } 664 /* 665 * Determine what the imbalance is and then adjust that to how many 666 * threads we actually have to give up (transferable). 667 */ 668 if (transferable != 0) { 669 diff = high_load - low_load; 670 move = diff / 2; 671 if (diff & 0x1) 672 move++; 673 move = min(move, transferable); 674 for (i = 0; i < move; i++) 675 tdq_move(high, low); 676 /* 677 * IPI the target cpu to force it to reschedule with the new 678 * workload. 679 */ 680 ipi_selected(1 << TDQ_ID(low), IPI_PREEMPT); 681 } 682 tdq_unlock_pair(high, low); 683 return; 684 } 685 686 /* 687 * Move a thread from one thread queue to another. 688 */ 689 static void 690 tdq_move(struct tdq *from, struct tdq *to) 691 { 692 struct td_sched *ts; 693 struct thread *td; 694 struct tdq *tdq; 695 int cpu; 696 697 TDQ_LOCK_ASSERT(from, MA_OWNED); 698 TDQ_LOCK_ASSERT(to, MA_OWNED); 699 700 tdq = from; 701 cpu = TDQ_ID(to); 702 ts = tdq_steal(tdq); 703 if (ts == NULL) { 704 struct tdq_group *tdg; 705 706 tdg = tdq->tdq_group; 707 LIST_FOREACH(tdq, &tdg->tdg_members, tdq_siblings) { 708 if (tdq == from || tdq->tdq_transferable == 0) 709 continue; 710 ts = tdq_steal(tdq); 711 break; 712 } 713 if (ts == NULL) 714 return; 715 } 716 if (tdq == to) 717 return; 718 td = ts->ts_thread; 719 /* 720 * Although the run queue is locked the thread may be blocked. Lock 721 * it to clear this and acquire the run-queue lock. 722 */ 723 thread_lock(td); 724 /* Drop recursive lock on from acquired via thread_lock(). */ 725 TDQ_UNLOCK(from); 726 sched_rem(td); 727 ts->ts_cpu = cpu; 728 td->td_lock = TDQ_LOCKPTR(to); 729 tdq_add(to, td, SRQ_YIELDING); 730 } 731 732 /* 733 * This tdq has idled. Try to steal a thread from another cpu and switch 734 * to it. 735 */ 736 static int 737 tdq_idled(struct tdq *tdq) 738 { 739 struct tdq_group *tdg; 740 struct tdq *steal; 741 int highload; 742 int highcpu; 743 int cpu; 744 745 if (smp_started == 0 || steal_idle == 0) 746 return (1); 747 /* We don't want to be preempted while we're iterating over tdqs */ 748 spinlock_enter(); 749 tdg = tdq->tdq_group; 750 /* 751 * If we're in a cpu group, try and steal threads from another cpu in 752 * the group before idling. In a HTT group all cpus share the same 753 * run-queue lock, however, we still need a recursive lock to 754 * call tdq_move(). 755 */ 756 if (steal_htt && tdg->tdg_cpus > 1 && tdg->tdg_transferable) { 757 TDQ_LOCK(tdq); 758 LIST_FOREACH(steal, &tdg->tdg_members, tdq_siblings) { 759 if (steal == tdq || steal->tdq_transferable == 0) 760 continue; 761 TDQ_LOCK(steal); 762 goto steal; 763 } 764 TDQ_UNLOCK(tdq); 765 } 766 /* 767 * Find the least loaded CPU with a transferable thread and attempt 768 * to steal it. We make a lockless pass and then verify that the 769 * thread is still available after locking. 770 */ 771 for (;;) { 772 highcpu = 0; 773 highload = 0; 774 for (cpu = 0; cpu <= mp_maxid; cpu++) { 775 if (CPU_ABSENT(cpu)) 776 continue; 777 steal = TDQ_CPU(cpu); 778 if (steal->tdq_transferable == 0) 779 continue; 780 if (steal->tdq_load < highload) 781 continue; 782 highload = steal->tdq_load; 783 highcpu = cpu; 784 } 785 if (highload < steal_thresh) 786 break; 787 steal = TDQ_CPU(highcpu); 788 if (steal == tdq) 789 break; 790 tdq_lock_pair(tdq, steal); 791 if (steal->tdq_load >= steal_thresh && steal->tdq_transferable) 792 goto steal; 793 tdq_unlock_pair(tdq, steal); 794 } 795 spinlock_exit(); 796 return (1); 797 steal: 798 spinlock_exit(); 799 tdq_move(steal, tdq); 800 TDQ_UNLOCK(steal); 801 mi_switch(SW_VOL, NULL); 802 thread_unlock(curthread); 803 804 return (0); 805 } 806 807 /* 808 * Notify a remote cpu of new work. Sends an IPI if criteria are met. 809 */ 810 static void 811 tdq_notify(struct td_sched *ts) 812 { 813 struct thread *ctd; 814 struct pcpu *pcpu; 815 int cpri; 816 int pri; 817 int cpu; 818 819 cpu = ts->ts_cpu; 820 pri = ts->ts_thread->td_priority; 821 pcpu = pcpu_find(cpu); 822 ctd = pcpu->pc_curthread; 823 cpri = ctd->td_priority; 824 825 /* 826 * If our priority is not better than the current priority there is 827 * nothing to do. 828 */ 829 if (pri > cpri) 830 return; 831 /* 832 * Always IPI idle. 833 */ 834 if (cpri > PRI_MIN_IDLE) 835 goto sendipi; 836 /* 837 * If we're realtime or better and there is timeshare or worse running 838 * send an IPI. 839 */ 840 if (pri < PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME) 841 goto sendipi; 842 /* 843 * Otherwise only IPI if we exceed the threshold. 844 */ 845 if (pri > preempt_thresh) 846 return; 847 sendipi: 848 ctd->td_flags |= TDF_NEEDRESCHED; 849 ipi_selected(1 << cpu, IPI_PREEMPT); 850 } 851 852 /* 853 * Steals load from a timeshare queue. Honors the rotating queue head 854 * index. 855 */ 856 static struct td_sched * 857 runq_steal_from(struct runq *rq, u_char start) 858 { 859 struct td_sched *ts; 860 struct rqbits *rqb; 861 struct rqhead *rqh; 862 int first; 863 int bit; 864 int pri; 865 int i; 866 867 rqb = &rq->rq_status; 868 bit = start & (RQB_BPW -1); 869 pri = 0; 870 first = 0; 871 again: 872 for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) { 873 if (rqb->rqb_bits[i] == 0) 874 continue; 875 if (bit != 0) { 876 for (pri = bit; pri < RQB_BPW; pri++) 877 if (rqb->rqb_bits[i] & (1ul << pri)) 878 break; 879 if (pri >= RQB_BPW) 880 continue; 881 } else 882 pri = RQB_FFS(rqb->rqb_bits[i]); 883 pri += (i << RQB_L2BPW); 884 rqh = &rq->rq_queues[pri]; 885 TAILQ_FOREACH(ts, rqh, ts_procq) { 886 if (first && THREAD_CAN_MIGRATE(ts->ts_thread)) 887 return (ts); 888 first = 1; 889 } 890 } 891 if (start != 0) { 892 start = 0; 893 goto again; 894 } 895 896 return (NULL); 897 } 898 899 /* 900 * Steals load from a standard linear queue. 901 */ 902 static struct td_sched * 903 runq_steal(struct runq *rq) 904 { 905 struct rqhead *rqh; 906 struct rqbits *rqb; 907 struct td_sched *ts; 908 int word; 909 int bit; 910 911 rqb = &rq->rq_status; 912 for (word = 0; word < RQB_LEN; word++) { 913 if (rqb->rqb_bits[word] == 0) 914 continue; 915 for (bit = 0; bit < RQB_BPW; bit++) { 916 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) 917 continue; 918 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; 919 TAILQ_FOREACH(ts, rqh, ts_procq) 920 if (THREAD_CAN_MIGRATE(ts->ts_thread)) 921 return (ts); 922 } 923 } 924 return (NULL); 925 } 926 927 /* 928 * Attempt to steal a thread in priority order from a thread queue. 929 */ 930 static struct td_sched * 931 tdq_steal(struct tdq *tdq) 932 { 933 struct td_sched *ts; 934 935 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 936 if ((ts = runq_steal(&tdq->tdq_realtime)) != NULL) 937 return (ts); 938 if ((ts = runq_steal_from(&tdq->tdq_timeshare, tdq->tdq_ridx)) != NULL) 939 return (ts); 940 return (runq_steal(&tdq->tdq_idle)); 941 } 942 943 /* 944 * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the 945 * current lock and returns with the assigned queue locked. 946 */ 947 static inline struct tdq * 948 sched_setcpu(struct td_sched *ts, int cpu, int flags) 949 { 950 struct thread *td; 951 struct tdq *tdq; 952 953 THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); 954 955 tdq = TDQ_CPU(cpu); 956 td = ts->ts_thread; 957 ts->ts_cpu = cpu; 958 959 /* If the lock matches just return the queue. */ 960 if (td->td_lock == TDQ_LOCKPTR(tdq)) 961 return (tdq); 962 #ifdef notyet 963 /* 964 * If the thread isn't running its lockptr is a 965 * turnstile or a sleepqueue. We can just lock_set without 966 * blocking. 967 */ 968 if (TD_CAN_RUN(td)) { 969 TDQ_LOCK(tdq); 970 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 971 return (tdq); 972 } 973 #endif 974 /* 975 * The hard case, migration, we need to block the thread first to 976 * prevent order reversals with other cpus locks. 977 */ 978 thread_lock_block(td); 979 TDQ_LOCK(tdq); 980 thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); 981 return (tdq); 982 } 983 984 /* 985 * Find the thread queue running the lowest priority thread. 986 */ 987 static int 988 tdq_lowestpri(void) 989 { 990 struct tdq *tdq; 991 int lowpri; 992 int lowcpu; 993 int lowload; 994 int load; 995 int cpu; 996 int pri; 997 998 lowload = 0; 999 lowpri = lowcpu = 0; 1000 for (cpu = 0; cpu <= mp_maxid; cpu++) { 1001 if (CPU_ABSENT(cpu)) 1002 continue; 1003 tdq = TDQ_CPU(cpu); 1004 pri = tdq->tdq_lowpri; 1005 load = TDQ_CPU(cpu)->tdq_load; 1006 CTR4(KTR_ULE, 1007 "cpu %d pri %d lowcpu %d lowpri %d", 1008 cpu, pri, lowcpu, lowpri); 1009 if (pri < lowpri) 1010 continue; 1011 if (lowpri && lowpri == pri && load > lowload) 1012 continue; 1013 lowpri = pri; 1014 lowcpu = cpu; 1015 lowload = load; 1016 } 1017 1018 return (lowcpu); 1019 } 1020 1021 /* 1022 * Find the thread queue with the least load. 1023 */ 1024 static int 1025 tdq_lowestload(void) 1026 { 1027 struct tdq *tdq; 1028 int lowload; 1029 int lowpri; 1030 int lowcpu; 1031 int load; 1032 int cpu; 1033 int pri; 1034 1035 lowcpu = 0; 1036 lowload = TDQ_CPU(0)->tdq_load; 1037 lowpri = TDQ_CPU(0)->tdq_lowpri; 1038 for (cpu = 1; cpu <= mp_maxid; cpu++) { 1039 if (CPU_ABSENT(cpu)) 1040 continue; 1041 tdq = TDQ_CPU(cpu); 1042 load = tdq->tdq_load; 1043 pri = tdq->tdq_lowpri; 1044 CTR4(KTR_ULE, "cpu %d load %d lowcpu %d lowload %d", 1045 cpu, load, lowcpu, lowload); 1046 if (load > lowload) 1047 continue; 1048 if (load == lowload && pri < lowpri) 1049 continue; 1050 lowcpu = cpu; 1051 lowload = load; 1052 lowpri = pri; 1053 } 1054 1055 return (lowcpu); 1056 } 1057 1058 /* 1059 * Pick the destination cpu for sched_add(). Respects affinity and makes 1060 * a determination based on load or priority of available processors. 1061 */ 1062 static int 1063 sched_pickcpu(struct td_sched *ts, int flags) 1064 { 1065 struct tdq *tdq; 1066 int self; 1067 int pri; 1068 int cpu; 1069 1070 cpu = self = PCPU_GET(cpuid); 1071 if (smp_started == 0) 1072 return (self); 1073 /* 1074 * Don't migrate a running thread from sched_switch(). 1075 */ 1076 if (flags & SRQ_OURSELF) { 1077 CTR1(KTR_ULE, "YIELDING %d", 1078 curthread->td_priority); 1079 return (self); 1080 } 1081 pri = ts->ts_thread->td_priority; 1082 cpu = ts->ts_cpu; 1083 /* 1084 * Regardless of affinity, if the last cpu is idle send it there. 1085 */ 1086 tdq = TDQ_CPU(cpu); 1087 if (tdq->tdq_lowpri > PRI_MIN_IDLE) { 1088 CTR5(KTR_ULE, 1089 "ts_cpu %d idle, ltick %d ticks %d pri %d curthread %d", 1090 ts->ts_cpu, ts->ts_rltick, ticks, pri, 1091 tdq->tdq_lowpri); 1092 return (ts->ts_cpu); 1093 } 1094 /* 1095 * If we have affinity, try to place it on the cpu we last ran on. 1096 */ 1097 if (SCHED_AFFINITY(ts) && tdq->tdq_lowpri > pri) { 1098 CTR5(KTR_ULE, 1099 "affinity for %d, ltick %d ticks %d pri %d curthread %d", 1100 ts->ts_cpu, ts->ts_rltick, ticks, pri, 1101 tdq->tdq_lowpri); 1102 return (ts->ts_cpu); 1103 } 1104 /* 1105 * Look for an idle group. 1106 */ 1107 CTR1(KTR_ULE, "tdq_idle %X", tdq_idle); 1108 cpu = ffs(tdq_idle); 1109 if (cpu) 1110 return (--cpu); 1111 /* 1112 * If there are no idle cores see if we can run the thread locally. 1113 * This may improve locality among sleepers and wakers when there 1114 * is shared data. 1115 */ 1116 if (tryself && pri < curthread->td_priority) { 1117 CTR1(KTR_ULE, "tryself %d", 1118 curthread->td_priority); 1119 return (self); 1120 } 1121 /* 1122 * Now search for the cpu running the lowest priority thread with 1123 * the least load. 1124 */ 1125 if (pick_pri) 1126 cpu = tdq_lowestpri(); 1127 else 1128 cpu = tdq_lowestload(); 1129 return (cpu); 1130 } 1131 1132 #endif /* SMP */ 1133 1134 /* 1135 * Pick the highest priority task we have and return it. 1136 */ 1137 static struct td_sched * 1138 tdq_choose(struct tdq *tdq) 1139 { 1140 struct td_sched *ts; 1141 1142 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1143 ts = runq_choose(&tdq->tdq_realtime); 1144 if (ts != NULL) 1145 return (ts); 1146 ts = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); 1147 if (ts != NULL) { 1148 KASSERT(ts->ts_thread->td_priority >= PRI_MIN_TIMESHARE, 1149 ("tdq_choose: Invalid priority on timeshare queue %d", 1150 ts->ts_thread->td_priority)); 1151 return (ts); 1152 } 1153 1154 ts = runq_choose(&tdq->tdq_idle); 1155 if (ts != NULL) { 1156 KASSERT(ts->ts_thread->td_priority >= PRI_MIN_IDLE, 1157 ("tdq_choose: Invalid priority on idle queue %d", 1158 ts->ts_thread->td_priority)); 1159 return (ts); 1160 } 1161 1162 return (NULL); 1163 } 1164 1165 /* 1166 * Initialize a thread queue. 1167 */ 1168 static void 1169 tdq_setup(struct tdq *tdq) 1170 { 1171 1172 if (bootverbose) 1173 printf("ULE: setup cpu %d\n", TDQ_ID(tdq)); 1174 runq_init(&tdq->tdq_realtime); 1175 runq_init(&tdq->tdq_timeshare); 1176 runq_init(&tdq->tdq_idle); 1177 tdq->tdq_load = 0; 1178 } 1179 1180 #ifdef SMP 1181 static void 1182 tdg_setup(struct tdq_group *tdg) 1183 { 1184 if (bootverbose) 1185 printf("ULE: setup cpu group %d\n", TDG_ID(tdg)); 1186 snprintf(tdg->tdg_name, sizeof(tdg->tdg_name), 1187 "sched lock %d", (int)TDG_ID(tdg)); 1188 mtx_init(&tdg->tdg_lock, tdg->tdg_name, "sched lock", 1189 MTX_SPIN | MTX_RECURSE); 1190 LIST_INIT(&tdg->tdg_members); 1191 tdg->tdg_load = 0; 1192 tdg->tdg_transferable = 0; 1193 tdg->tdg_cpus = 0; 1194 tdg->tdg_mask = 0; 1195 tdg->tdg_cpumask = 0; 1196 tdg->tdg_idlemask = 0; 1197 } 1198 1199 static void 1200 tdg_add(struct tdq_group *tdg, struct tdq *tdq) 1201 { 1202 if (tdg->tdg_mask == 0) 1203 tdg->tdg_mask |= 1 << TDQ_ID(tdq); 1204 tdg->tdg_cpumask |= 1 << TDQ_ID(tdq); 1205 tdg->tdg_cpus++; 1206 tdq->tdq_group = tdg; 1207 tdq->tdq_lock = &tdg->tdg_lock; 1208 LIST_INSERT_HEAD(&tdg->tdg_members, tdq, tdq_siblings); 1209 if (bootverbose) 1210 printf("ULE: adding cpu %d to group %d: cpus %d mask 0x%X\n", 1211 TDQ_ID(tdq), TDG_ID(tdg), tdg->tdg_cpus, tdg->tdg_cpumask); 1212 } 1213 1214 static void 1215 sched_setup_topology(void) 1216 { 1217 struct tdq_group *tdg; 1218 struct cpu_group *cg; 1219 int balance_groups; 1220 struct tdq *tdq; 1221 int i; 1222 int j; 1223 1224 topology = 1; 1225 balance_groups = 0; 1226 for (i = 0; i < smp_topology->ct_count; i++) { 1227 cg = &smp_topology->ct_group[i]; 1228 tdg = &tdq_groups[i]; 1229 /* 1230 * Initialize the group. 1231 */ 1232 tdg_setup(tdg); 1233 /* 1234 * Find all of the group members and add them. 1235 */ 1236 for (j = 0; j < MAXCPU; j++) { 1237 if ((cg->cg_mask & (1 << j)) != 0) { 1238 tdq = TDQ_CPU(j); 1239 tdq_setup(tdq); 1240 tdg_add(tdg, tdq); 1241 } 1242 } 1243 if (tdg->tdg_cpus > 1) 1244 balance_groups = 1; 1245 } 1246 tdg_maxid = smp_topology->ct_count - 1; 1247 if (balance_groups) 1248 sched_balance_groups(); 1249 } 1250 1251 static void 1252 sched_setup_smp(void) 1253 { 1254 struct tdq_group *tdg; 1255 struct tdq *tdq; 1256 int cpus; 1257 int i; 1258 1259 for (cpus = 0, i = 0; i < MAXCPU; i++) { 1260 if (CPU_ABSENT(i)) 1261 continue; 1262 tdq = &tdq_cpu[i]; 1263 tdg = &tdq_groups[i]; 1264 /* 1265 * Setup a tdq group with one member. 1266 */ 1267 tdg_setup(tdg); 1268 tdq_setup(tdq); 1269 tdg_add(tdg, tdq); 1270 cpus++; 1271 } 1272 tdg_maxid = cpus - 1; 1273 } 1274 1275 /* 1276 * Fake a topology with one group containing all CPUs. 1277 */ 1278 static void 1279 sched_fake_topo(void) 1280 { 1281 #ifdef SCHED_FAKE_TOPOLOGY 1282 static struct cpu_top top; 1283 static struct cpu_group group; 1284 1285 top.ct_count = 1; 1286 top.ct_group = &group; 1287 group.cg_mask = all_cpus; 1288 group.cg_count = mp_ncpus; 1289 group.cg_children = 0; 1290 smp_topology = ⊤ 1291 #endif 1292 } 1293 #endif 1294 1295 /* 1296 * Setup the thread queues and initialize the topology based on MD 1297 * information. 1298 */ 1299 static void 1300 sched_setup(void *dummy) 1301 { 1302 struct tdq *tdq; 1303 1304 tdq = TDQ_SELF(); 1305 #ifdef SMP 1306 sched_fake_topo(); 1307 /* 1308 * Setup tdqs based on a topology configuration or vanilla SMP based 1309 * on mp_maxid. 1310 */ 1311 if (smp_topology == NULL) 1312 sched_setup_smp(); 1313 else 1314 sched_setup_topology(); 1315 balance_tdq = tdq; 1316 sched_balance(); 1317 #else 1318 tdq_setup(tdq); 1319 mtx_init(&tdq_lock, "sched lock", "sched lock", MTX_SPIN | MTX_RECURSE); 1320 tdq->tdq_lock = &tdq_lock; 1321 #endif 1322 /* 1323 * To avoid divide-by-zero, we set realstathz a dummy value 1324 * in case which sched_clock() called before sched_initticks(). 1325 */ 1326 realstathz = hz; 1327 sched_slice = (realstathz/10); /* ~100ms */ 1328 tickincr = 1 << SCHED_TICK_SHIFT; 1329 1330 /* Add thread0's load since it's running. */ 1331 TDQ_LOCK(tdq); 1332 thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1333 tdq_load_add(tdq, &td_sched0); 1334 TDQ_UNLOCK(tdq); 1335 } 1336 1337 /* 1338 * This routine determines the tickincr after stathz and hz are setup. 1339 */ 1340 /* ARGSUSED */ 1341 static void 1342 sched_initticks(void *dummy) 1343 { 1344 int incr; 1345 1346 realstathz = stathz ? stathz : hz; 1347 sched_slice = (realstathz/10); /* ~100ms */ 1348 1349 /* 1350 * tickincr is shifted out by 10 to avoid rounding errors due to 1351 * hz not being evenly divisible by stathz on all platforms. 1352 */ 1353 incr = (hz << SCHED_TICK_SHIFT) / realstathz; 1354 /* 1355 * This does not work for values of stathz that are more than 1356 * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen. 1357 */ 1358 if (incr == 0) 1359 incr = 1; 1360 tickincr = incr; 1361 #ifdef SMP 1362 /* 1363 * Set the default balance interval now that we know 1364 * what realstathz is. 1365 */ 1366 balance_interval = realstathz; 1367 /* 1368 * Set steal thresh to log2(mp_ncpu) but no greater than 4. This 1369 * prevents excess thrashing on large machines and excess idle on 1370 * smaller machines. 1371 */ 1372 steal_thresh = min(ffs(mp_ncpus) - 1, 4); 1373 affinity = SCHED_AFFINITY_DEFAULT; 1374 #endif 1375 } 1376 1377 1378 /* 1379 * This is the core of the interactivity algorithm. Determines a score based 1380 * on past behavior. It is the ratio of sleep time to run time scaled to 1381 * a [0, 100] integer. This is the voluntary sleep time of a process, which 1382 * differs from the cpu usage because it does not account for time spent 1383 * waiting on a run-queue. Would be prettier if we had floating point. 1384 */ 1385 static int 1386 sched_interact_score(struct thread *td) 1387 { 1388 struct td_sched *ts; 1389 int div; 1390 1391 ts = td->td_sched; 1392 /* 1393 * The score is only needed if this is likely to be an interactive 1394 * task. Don't go through the expense of computing it if there's 1395 * no chance. 1396 */ 1397 if (sched_interact <= SCHED_INTERACT_HALF && 1398 ts->ts_runtime >= ts->ts_slptime) 1399 return (SCHED_INTERACT_HALF); 1400 1401 if (ts->ts_runtime > ts->ts_slptime) { 1402 div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF); 1403 return (SCHED_INTERACT_HALF + 1404 (SCHED_INTERACT_HALF - (ts->ts_slptime / div))); 1405 } 1406 if (ts->ts_slptime > ts->ts_runtime) { 1407 div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF); 1408 return (ts->ts_runtime / div); 1409 } 1410 /* runtime == slptime */ 1411 if (ts->ts_runtime) 1412 return (SCHED_INTERACT_HALF); 1413 1414 /* 1415 * This can happen if slptime and runtime are 0. 1416 */ 1417 return (0); 1418 1419 } 1420 1421 /* 1422 * Scale the scheduling priority according to the "interactivity" of this 1423 * process. 1424 */ 1425 static void 1426 sched_priority(struct thread *td) 1427 { 1428 int score; 1429 int pri; 1430 1431 if (td->td_pri_class != PRI_TIMESHARE) 1432 return; 1433 /* 1434 * If the score is interactive we place the thread in the realtime 1435 * queue with a priority that is less than kernel and interrupt 1436 * priorities. These threads are not subject to nice restrictions. 1437 * 1438 * Scores greater than this are placed on the normal timeshare queue 1439 * where the priority is partially decided by the most recent cpu 1440 * utilization and the rest is decided by nice value. 1441 * 1442 * The nice value of the process has a linear effect on the calculated 1443 * score. Negative nice values make it easier for a thread to be 1444 * considered interactive. 1445 */ 1446 score = imax(0, sched_interact_score(td) - td->td_proc->p_nice); 1447 if (score < sched_interact) { 1448 pri = PRI_MIN_REALTIME; 1449 pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME) / sched_interact) 1450 * score; 1451 KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME, 1452 ("sched_priority: invalid interactive priority %d score %d", 1453 pri, score)); 1454 } else { 1455 pri = SCHED_PRI_MIN; 1456 if (td->td_sched->ts_ticks) 1457 pri += SCHED_PRI_TICKS(td->td_sched); 1458 pri += SCHED_PRI_NICE(td->td_proc->p_nice); 1459 KASSERT(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE, 1460 ("sched_priority: invalid priority %d: nice %d, " 1461 "ticks %d ftick %d ltick %d tick pri %d", 1462 pri, td->td_proc->p_nice, td->td_sched->ts_ticks, 1463 td->td_sched->ts_ftick, td->td_sched->ts_ltick, 1464 SCHED_PRI_TICKS(td->td_sched))); 1465 } 1466 sched_user_prio(td, pri); 1467 1468 return; 1469 } 1470 1471 /* 1472 * This routine enforces a maximum limit on the amount of scheduling history 1473 * kept. It is called after either the slptime or runtime is adjusted. This 1474 * function is ugly due to integer math. 1475 */ 1476 static void 1477 sched_interact_update(struct thread *td) 1478 { 1479 struct td_sched *ts; 1480 u_int sum; 1481 1482 ts = td->td_sched; 1483 sum = ts->ts_runtime + ts->ts_slptime; 1484 if (sum < SCHED_SLP_RUN_MAX) 1485 return; 1486 /* 1487 * This only happens from two places: 1488 * 1) We have added an unusual amount of run time from fork_exit. 1489 * 2) We have added an unusual amount of sleep time from sched_sleep(). 1490 */ 1491 if (sum > SCHED_SLP_RUN_MAX * 2) { 1492 if (ts->ts_runtime > ts->ts_slptime) { 1493 ts->ts_runtime = SCHED_SLP_RUN_MAX; 1494 ts->ts_slptime = 1; 1495 } else { 1496 ts->ts_slptime = SCHED_SLP_RUN_MAX; 1497 ts->ts_runtime = 1; 1498 } 1499 return; 1500 } 1501 /* 1502 * If we have exceeded by more than 1/5th then the algorithm below 1503 * will not bring us back into range. Dividing by two here forces 1504 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] 1505 */ 1506 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { 1507 ts->ts_runtime /= 2; 1508 ts->ts_slptime /= 2; 1509 return; 1510 } 1511 ts->ts_runtime = (ts->ts_runtime / 5) * 4; 1512 ts->ts_slptime = (ts->ts_slptime / 5) * 4; 1513 } 1514 1515 /* 1516 * Scale back the interactivity history when a child thread is created. The 1517 * history is inherited from the parent but the thread may behave totally 1518 * differently. For example, a shell spawning a compiler process. We want 1519 * to learn that the compiler is behaving badly very quickly. 1520 */ 1521 static void 1522 sched_interact_fork(struct thread *td) 1523 { 1524 int ratio; 1525 int sum; 1526 1527 sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime; 1528 if (sum > SCHED_SLP_RUN_FORK) { 1529 ratio = sum / SCHED_SLP_RUN_FORK; 1530 td->td_sched->ts_runtime /= ratio; 1531 td->td_sched->ts_slptime /= ratio; 1532 } 1533 } 1534 1535 /* 1536 * Called from proc0_init() to setup the scheduler fields. 1537 */ 1538 void 1539 schedinit(void) 1540 { 1541 1542 /* 1543 * Set up the scheduler specific parts of proc0. 1544 */ 1545 proc0.p_sched = NULL; /* XXX */ 1546 thread0.td_sched = &td_sched0; 1547 td_sched0.ts_ltick = ticks; 1548 td_sched0.ts_ftick = ticks; 1549 td_sched0.ts_thread = &thread0; 1550 } 1551 1552 /* 1553 * This is only somewhat accurate since given many processes of the same 1554 * priority they will switch when their slices run out, which will be 1555 * at most sched_slice stathz ticks. 1556 */ 1557 int 1558 sched_rr_interval(void) 1559 { 1560 1561 /* Convert sched_slice to hz */ 1562 return (hz/(realstathz/sched_slice)); 1563 } 1564 1565 /* 1566 * Update the percent cpu tracking information when it is requested or 1567 * the total history exceeds the maximum. We keep a sliding history of 1568 * tick counts that slowly decays. This is less precise than the 4BSD 1569 * mechanism since it happens with less regular and frequent events. 1570 */ 1571 static void 1572 sched_pctcpu_update(struct td_sched *ts) 1573 { 1574 1575 if (ts->ts_ticks == 0) 1576 return; 1577 if (ticks - (hz / 10) < ts->ts_ltick && 1578 SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX) 1579 return; 1580 /* 1581 * Adjust counters and watermark for pctcpu calc. 1582 */ 1583 if (ts->ts_ltick > ticks - SCHED_TICK_TARG) 1584 ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) * 1585 SCHED_TICK_TARG; 1586 else 1587 ts->ts_ticks = 0; 1588 ts->ts_ltick = ticks; 1589 ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG; 1590 } 1591 1592 /* 1593 * Adjust the priority of a thread. Move it to the appropriate run-queue 1594 * if necessary. This is the back-end for several priority related 1595 * functions. 1596 */ 1597 static void 1598 sched_thread_priority(struct thread *td, u_char prio) 1599 { 1600 struct td_sched *ts; 1601 1602 CTR6(KTR_SCHED, "sched_prio: %p(%s) prio %d newprio %d by %p(%s)", 1603 td, td->td_proc->p_comm, td->td_priority, prio, curthread, 1604 curthread->td_proc->p_comm); 1605 ts = td->td_sched; 1606 THREAD_LOCK_ASSERT(td, MA_OWNED); 1607 if (td->td_priority == prio) 1608 return; 1609 1610 if (TD_ON_RUNQ(td) && prio < td->td_priority) { 1611 /* 1612 * If the priority has been elevated due to priority 1613 * propagation, we may have to move ourselves to a new 1614 * queue. This could be optimized to not re-add in some 1615 * cases. 1616 */ 1617 sched_rem(td); 1618 td->td_priority = prio; 1619 sched_add(td, SRQ_BORROWING); 1620 } else { 1621 #ifdef SMP 1622 struct tdq *tdq; 1623 1624 tdq = TDQ_CPU(ts->ts_cpu); 1625 if (prio < tdq->tdq_lowpri) 1626 tdq->tdq_lowpri = prio; 1627 #endif 1628 td->td_priority = prio; 1629 } 1630 } 1631 1632 /* 1633 * Update a thread's priority when it is lent another thread's 1634 * priority. 1635 */ 1636 void 1637 sched_lend_prio(struct thread *td, u_char prio) 1638 { 1639 1640 td->td_flags |= TDF_BORROWING; 1641 sched_thread_priority(td, prio); 1642 } 1643 1644 /* 1645 * Restore a thread's priority when priority propagation is 1646 * over. The prio argument is the minimum priority the thread 1647 * needs to have to satisfy other possible priority lending 1648 * requests. If the thread's regular priority is less 1649 * important than prio, the thread will keep a priority boost 1650 * of prio. 1651 */ 1652 void 1653 sched_unlend_prio(struct thread *td, u_char prio) 1654 { 1655 u_char base_pri; 1656 1657 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 1658 td->td_base_pri <= PRI_MAX_TIMESHARE) 1659 base_pri = td->td_user_pri; 1660 else 1661 base_pri = td->td_base_pri; 1662 if (prio >= base_pri) { 1663 td->td_flags &= ~TDF_BORROWING; 1664 sched_thread_priority(td, base_pri); 1665 } else 1666 sched_lend_prio(td, prio); 1667 } 1668 1669 /* 1670 * Standard entry for setting the priority to an absolute value. 1671 */ 1672 void 1673 sched_prio(struct thread *td, u_char prio) 1674 { 1675 u_char oldprio; 1676 1677 /* First, update the base priority. */ 1678 td->td_base_pri = prio; 1679 1680 /* 1681 * If the thread is borrowing another thread's priority, don't 1682 * ever lower the priority. 1683 */ 1684 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 1685 return; 1686 1687 /* Change the real priority. */ 1688 oldprio = td->td_priority; 1689 sched_thread_priority(td, prio); 1690 1691 /* 1692 * If the thread is on a turnstile, then let the turnstile update 1693 * its state. 1694 */ 1695 if (TD_ON_LOCK(td) && oldprio != prio) 1696 turnstile_adjust(td, oldprio); 1697 } 1698 1699 /* 1700 * Set the base user priority, does not effect current running priority. 1701 */ 1702 void 1703 sched_user_prio(struct thread *td, u_char prio) 1704 { 1705 u_char oldprio; 1706 1707 td->td_base_user_pri = prio; 1708 if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio) 1709 return; 1710 oldprio = td->td_user_pri; 1711 td->td_user_pri = prio; 1712 1713 if (TD_ON_UPILOCK(td) && oldprio != prio) 1714 umtx_pi_adjust(td, oldprio); 1715 } 1716 1717 void 1718 sched_lend_user_prio(struct thread *td, u_char prio) 1719 { 1720 u_char oldprio; 1721 1722 td->td_flags |= TDF_UBORROWING; 1723 1724 oldprio = td->td_user_pri; 1725 td->td_user_pri = prio; 1726 1727 if (TD_ON_UPILOCK(td) && oldprio != prio) 1728 umtx_pi_adjust(td, oldprio); 1729 } 1730 1731 void 1732 sched_unlend_user_prio(struct thread *td, u_char prio) 1733 { 1734 u_char base_pri; 1735 1736 base_pri = td->td_base_user_pri; 1737 if (prio >= base_pri) { 1738 td->td_flags &= ~TDF_UBORROWING; 1739 sched_user_prio(td, base_pri); 1740 } else 1741 sched_lend_user_prio(td, prio); 1742 } 1743 1744 /* 1745 * Add the thread passed as 'newtd' to the run queue before selecting 1746 * the next thread to run. This is only used for KSE. 1747 */ 1748 static void 1749 sched_switchin(struct tdq *tdq, struct thread *td) 1750 { 1751 #ifdef SMP 1752 spinlock_enter(); 1753 TDQ_UNLOCK(tdq); 1754 thread_lock(td); 1755 spinlock_exit(); 1756 sched_setcpu(td->td_sched, TDQ_ID(tdq), SRQ_YIELDING); 1757 #else 1758 td->td_lock = TDQ_LOCKPTR(tdq); 1759 #endif 1760 tdq_add(tdq, td, SRQ_YIELDING); 1761 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1762 } 1763 1764 /* 1765 * Handle migration from sched_switch(). This happens only for 1766 * cpu binding. 1767 */ 1768 static struct mtx * 1769 sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) 1770 { 1771 struct tdq *tdn; 1772 1773 tdn = TDQ_CPU(td->td_sched->ts_cpu); 1774 #ifdef SMP 1775 /* 1776 * Do the lock dance required to avoid LOR. We grab an extra 1777 * spinlock nesting to prevent preemption while we're 1778 * not holding either run-queue lock. 1779 */ 1780 spinlock_enter(); 1781 thread_block_switch(td); /* This releases the lock on tdq. */ 1782 TDQ_LOCK(tdn); 1783 tdq_add(tdn, td, flags); 1784 tdq_notify(td->td_sched); 1785 /* 1786 * After we unlock tdn the new cpu still can't switch into this 1787 * thread until we've unblocked it in cpu_switch(). The lock 1788 * pointers may match in the case of HTT cores. Don't unlock here 1789 * or we can deadlock when the other CPU runs the IPI handler. 1790 */ 1791 if (TDQ_LOCKPTR(tdn) != TDQ_LOCKPTR(tdq)) { 1792 TDQ_UNLOCK(tdn); 1793 TDQ_LOCK(tdq); 1794 } 1795 spinlock_exit(); 1796 #endif 1797 return (TDQ_LOCKPTR(tdn)); 1798 } 1799 1800 /* 1801 * Block a thread for switching. Similar to thread_block() but does not 1802 * bump the spin count. 1803 */ 1804 static inline struct mtx * 1805 thread_block_switch(struct thread *td) 1806 { 1807 struct mtx *lock; 1808 1809 THREAD_LOCK_ASSERT(td, MA_OWNED); 1810 lock = td->td_lock; 1811 td->td_lock = &blocked_lock; 1812 mtx_unlock_spin(lock); 1813 1814 return (lock); 1815 } 1816 1817 /* 1818 * Release a thread that was blocked with thread_block_switch(). 1819 */ 1820 static inline void 1821 thread_unblock_switch(struct thread *td, struct mtx *mtx) 1822 { 1823 atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock, 1824 (uintptr_t)mtx); 1825 } 1826 1827 /* 1828 * Switch threads. This function has to handle threads coming in while 1829 * blocked for some reason, running, or idle. It also must deal with 1830 * migrating a thread from one queue to another as running threads may 1831 * be assigned elsewhere via binding. 1832 */ 1833 void 1834 sched_switch(struct thread *td, struct thread *newtd, int flags) 1835 { 1836 struct tdq *tdq; 1837 struct td_sched *ts; 1838 struct mtx *mtx; 1839 int srqflag; 1840 int cpuid; 1841 1842 THREAD_LOCK_ASSERT(td, MA_OWNED); 1843 1844 cpuid = PCPU_GET(cpuid); 1845 tdq = TDQ_CPU(cpuid); 1846 ts = td->td_sched; 1847 mtx = td->td_lock; 1848 #ifdef SMP 1849 ts->ts_rltick = ticks; 1850 if (newtd && newtd->td_priority < tdq->tdq_lowpri) 1851 tdq->tdq_lowpri = newtd->td_priority; 1852 #endif 1853 td->td_lastcpu = td->td_oncpu; 1854 td->td_oncpu = NOCPU; 1855 td->td_flags &= ~TDF_NEEDRESCHED; 1856 td->td_owepreempt = 0; 1857 /* 1858 * The lock pointer in an idle thread should never change. Reset it 1859 * to CAN_RUN as well. 1860 */ 1861 if (TD_IS_IDLETHREAD(td)) { 1862 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1863 TD_SET_CAN_RUN(td); 1864 } else if (TD_IS_RUNNING(td)) { 1865 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1866 tdq_load_rem(tdq, ts); 1867 srqflag = (flags & SW_PREEMPT) ? 1868 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1869 SRQ_OURSELF|SRQ_YIELDING; 1870 if (ts->ts_cpu == cpuid) 1871 tdq_add(tdq, td, srqflag); 1872 else 1873 mtx = sched_switch_migrate(tdq, td, srqflag); 1874 } else { 1875 /* This thread must be going to sleep. */ 1876 TDQ_LOCK(tdq); 1877 mtx = thread_block_switch(td); 1878 tdq_load_rem(tdq, ts); 1879 } 1880 /* 1881 * We enter here with the thread blocked and assigned to the 1882 * appropriate cpu run-queue or sleep-queue and with the current 1883 * thread-queue locked. 1884 */ 1885 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 1886 /* 1887 * If KSE assigned a new thread just add it here and let choosethread 1888 * select the best one. 1889 */ 1890 if (newtd != NULL) 1891 sched_switchin(tdq, newtd); 1892 newtd = choosethread(); 1893 /* 1894 * Call the MD code to switch contexts if necessary. 1895 */ 1896 if (td != newtd) { 1897 #ifdef HWPMC_HOOKS 1898 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1899 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1900 #endif 1901 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 1902 cpu_switch(td, newtd, mtx); 1903 /* 1904 * We may return from cpu_switch on a different cpu. However, 1905 * we always return with td_lock pointing to the current cpu's 1906 * run queue lock. 1907 */ 1908 cpuid = PCPU_GET(cpuid); 1909 tdq = TDQ_CPU(cpuid); 1910 #ifdef HWPMC_HOOKS 1911 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1912 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1913 #endif 1914 } else 1915 thread_unblock_switch(td, mtx); 1916 /* 1917 * Assert that all went well and return. 1918 */ 1919 #ifdef SMP 1920 /* We should always get here with the lowest priority td possible */ 1921 tdq->tdq_lowpri = td->td_priority; 1922 #endif 1923 TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED); 1924 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1925 td->td_oncpu = cpuid; 1926 } 1927 1928 /* 1929 * Adjust thread priorities as a result of a nice request. 1930 */ 1931 void 1932 sched_nice(struct proc *p, int nice) 1933 { 1934 struct thread *td; 1935 1936 PROC_LOCK_ASSERT(p, MA_OWNED); 1937 PROC_SLOCK_ASSERT(p, MA_OWNED); 1938 1939 p->p_nice = nice; 1940 FOREACH_THREAD_IN_PROC(p, td) { 1941 thread_lock(td); 1942 sched_priority(td); 1943 sched_prio(td, td->td_base_user_pri); 1944 thread_unlock(td); 1945 } 1946 } 1947 1948 /* 1949 * Record the sleep time for the interactivity scorer. 1950 */ 1951 void 1952 sched_sleep(struct thread *td) 1953 { 1954 1955 THREAD_LOCK_ASSERT(td, MA_OWNED); 1956 1957 td->td_slptick = ticks; 1958 } 1959 1960 /* 1961 * Schedule a thread to resume execution and record how long it voluntarily 1962 * slept. We also update the pctcpu, interactivity, and priority. 1963 */ 1964 void 1965 sched_wakeup(struct thread *td) 1966 { 1967 struct td_sched *ts; 1968 int slptick; 1969 1970 THREAD_LOCK_ASSERT(td, MA_OWNED); 1971 ts = td->td_sched; 1972 /* 1973 * If we slept for more than a tick update our interactivity and 1974 * priority. 1975 */ 1976 slptick = td->td_slptick; 1977 td->td_slptick = 0; 1978 if (slptick && slptick != ticks) { 1979 u_int hzticks; 1980 1981 hzticks = (ticks - slptick) << SCHED_TICK_SHIFT; 1982 ts->ts_slptime += hzticks; 1983 sched_interact_update(td); 1984 sched_pctcpu_update(ts); 1985 sched_priority(td); 1986 } 1987 /* Reset the slice value after we sleep. */ 1988 ts->ts_slice = sched_slice; 1989 sched_add(td, SRQ_BORING); 1990 } 1991 1992 /* 1993 * Penalize the parent for creating a new child and initialize the child's 1994 * priority. 1995 */ 1996 void 1997 sched_fork(struct thread *td, struct thread *child) 1998 { 1999 THREAD_LOCK_ASSERT(td, MA_OWNED); 2000 sched_fork_thread(td, child); 2001 /* 2002 * Penalize the parent and child for forking. 2003 */ 2004 sched_interact_fork(child); 2005 sched_priority(child); 2006 td->td_sched->ts_runtime += tickincr; 2007 sched_interact_update(td); 2008 sched_priority(td); 2009 } 2010 2011 /* 2012 * Fork a new thread, may be within the same process. 2013 */ 2014 void 2015 sched_fork_thread(struct thread *td, struct thread *child) 2016 { 2017 struct td_sched *ts; 2018 struct td_sched *ts2; 2019 2020 /* 2021 * Initialize child. 2022 */ 2023 THREAD_LOCK_ASSERT(td, MA_OWNED); 2024 sched_newthread(child); 2025 child->td_lock = TDQ_LOCKPTR(TDQ_SELF()); 2026 ts = td->td_sched; 2027 ts2 = child->td_sched; 2028 ts2->ts_cpu = ts->ts_cpu; 2029 ts2->ts_runq = NULL; 2030 /* 2031 * Grab our parents cpu estimation information and priority. 2032 */ 2033 ts2->ts_ticks = ts->ts_ticks; 2034 ts2->ts_ltick = ts->ts_ltick; 2035 ts2->ts_ftick = ts->ts_ftick; 2036 child->td_user_pri = td->td_user_pri; 2037 child->td_base_user_pri = td->td_base_user_pri; 2038 /* 2039 * And update interactivity score. 2040 */ 2041 ts2->ts_slptime = ts->ts_slptime; 2042 ts2->ts_runtime = ts->ts_runtime; 2043 ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */ 2044 } 2045 2046 /* 2047 * Adjust the priority class of a thread. 2048 */ 2049 void 2050 sched_class(struct thread *td, int class) 2051 { 2052 2053 THREAD_LOCK_ASSERT(td, MA_OWNED); 2054 if (td->td_pri_class == class) 2055 return; 2056 2057 #ifdef SMP 2058 /* 2059 * On SMP if we're on the RUNQ we must adjust the transferable 2060 * count because could be changing to or from an interrupt 2061 * class. 2062 */ 2063 if (TD_ON_RUNQ(td)) { 2064 struct tdq *tdq; 2065 2066 tdq = TDQ_CPU(td->td_sched->ts_cpu); 2067 if (THREAD_CAN_MIGRATE(td)) { 2068 tdq->tdq_transferable--; 2069 tdq->tdq_group->tdg_transferable--; 2070 } 2071 td->td_pri_class = class; 2072 if (THREAD_CAN_MIGRATE(td)) { 2073 tdq->tdq_transferable++; 2074 tdq->tdq_group->tdg_transferable++; 2075 } 2076 } 2077 #endif 2078 td->td_pri_class = class; 2079 } 2080 2081 /* 2082 * Return some of the child's priority and interactivity to the parent. 2083 */ 2084 void 2085 sched_exit(struct proc *p, struct thread *child) 2086 { 2087 struct thread *td; 2088 2089 CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d", 2090 child, child->td_proc->p_comm, child->td_priority); 2091 2092 PROC_SLOCK_ASSERT(p, MA_OWNED); 2093 td = FIRST_THREAD_IN_PROC(p); 2094 sched_exit_thread(td, child); 2095 } 2096 2097 /* 2098 * Penalize another thread for the time spent on this one. This helps to 2099 * worsen the priority and interactivity of processes which schedule batch 2100 * jobs such as make. This has little effect on the make process itself but 2101 * causes new processes spawned by it to receive worse scores immediately. 2102 */ 2103 void 2104 sched_exit_thread(struct thread *td, struct thread *child) 2105 { 2106 2107 CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d", 2108 child, child->td_proc->p_comm, child->td_priority); 2109 2110 #ifdef KSE 2111 /* 2112 * KSE forks and exits so often that this penalty causes short-lived 2113 * threads to always be non-interactive. This causes mozilla to 2114 * crawl under load. 2115 */ 2116 if ((td->td_pflags & TDP_SA) && td->td_proc == child->td_proc) 2117 return; 2118 #endif 2119 /* 2120 * Give the child's runtime to the parent without returning the 2121 * sleep time as a penalty to the parent. This causes shells that 2122 * launch expensive things to mark their children as expensive. 2123 */ 2124 thread_lock(td); 2125 td->td_sched->ts_runtime += child->td_sched->ts_runtime; 2126 sched_interact_update(td); 2127 sched_priority(td); 2128 thread_unlock(td); 2129 } 2130 2131 /* 2132 * Fix priorities on return to user-space. Priorities may be elevated due 2133 * to static priorities in msleep() or similar. 2134 */ 2135 void 2136 sched_userret(struct thread *td) 2137 { 2138 /* 2139 * XXX we cheat slightly on the locking here to avoid locking in 2140 * the usual case. Setting td_priority here is essentially an 2141 * incomplete workaround for not setting it properly elsewhere. 2142 * Now that some interrupt handlers are threads, not setting it 2143 * properly elsewhere can clobber it in the window between setting 2144 * it here and returning to user mode, so don't waste time setting 2145 * it perfectly here. 2146 */ 2147 KASSERT((td->td_flags & TDF_BORROWING) == 0, 2148 ("thread with borrowed priority returning to userland")); 2149 if (td->td_priority != td->td_user_pri) { 2150 thread_lock(td); 2151 td->td_priority = td->td_user_pri; 2152 td->td_base_pri = td->td_user_pri; 2153 thread_unlock(td); 2154 } 2155 } 2156 2157 /* 2158 * Handle a stathz tick. This is really only relevant for timeshare 2159 * threads. 2160 */ 2161 void 2162 sched_clock(struct thread *td) 2163 { 2164 struct tdq *tdq; 2165 struct td_sched *ts; 2166 2167 THREAD_LOCK_ASSERT(td, MA_OWNED); 2168 tdq = TDQ_SELF(); 2169 #ifdef SMP 2170 /* 2171 * We run the long term load balancer infrequently on the first cpu. 2172 */ 2173 if (balance_tdq == tdq) { 2174 if (balance_ticks && --balance_ticks == 0) 2175 sched_balance(); 2176 if (balance_group_ticks && --balance_group_ticks == 0) 2177 sched_balance_groups(); 2178 } 2179 #endif 2180 /* 2181 * Advance the insert index once for each tick to ensure that all 2182 * threads get a chance to run. 2183 */ 2184 if (tdq->tdq_idx == tdq->tdq_ridx) { 2185 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; 2186 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) 2187 tdq->tdq_ridx = tdq->tdq_idx; 2188 } 2189 ts = td->td_sched; 2190 /* 2191 * We only do slicing code for TIMESHARE threads. 2192 */ 2193 if (td->td_pri_class != PRI_TIMESHARE) 2194 return; 2195 /* 2196 * We used a tick; charge it to the thread so that we can compute our 2197 * interactivity. 2198 */ 2199 td->td_sched->ts_runtime += tickincr; 2200 sched_interact_update(td); 2201 /* 2202 * We used up one time slice. 2203 */ 2204 if (--ts->ts_slice > 0) 2205 return; 2206 /* 2207 * We're out of time, recompute priorities and requeue. 2208 */ 2209 sched_priority(td); 2210 td->td_flags |= TDF_NEEDRESCHED; 2211 } 2212 2213 /* 2214 * Called once per hz tick. Used for cpu utilization information. This 2215 * is easier than trying to scale based on stathz. 2216 */ 2217 void 2218 sched_tick(void) 2219 { 2220 struct td_sched *ts; 2221 2222 ts = curthread->td_sched; 2223 /* Adjust ticks for pctcpu */ 2224 ts->ts_ticks += 1 << SCHED_TICK_SHIFT; 2225 ts->ts_ltick = ticks; 2226 /* 2227 * Update if we've exceeded our desired tick threshhold by over one 2228 * second. 2229 */ 2230 if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick) 2231 sched_pctcpu_update(ts); 2232 } 2233 2234 /* 2235 * Return whether the current CPU has runnable tasks. Used for in-kernel 2236 * cooperative idle threads. 2237 */ 2238 int 2239 sched_runnable(void) 2240 { 2241 struct tdq *tdq; 2242 int load; 2243 2244 load = 1; 2245 2246 tdq = TDQ_SELF(); 2247 if ((curthread->td_flags & TDF_IDLETD) != 0) { 2248 if (tdq->tdq_load > 0) 2249 goto out; 2250 } else 2251 if (tdq->tdq_load - 1 > 0) 2252 goto out; 2253 load = 0; 2254 out: 2255 return (load); 2256 } 2257 2258 /* 2259 * Choose the highest priority thread to run. The thread is removed from 2260 * the run-queue while running however the load remains. For SMP we set 2261 * the tdq in the global idle bitmask if it idles here. 2262 */ 2263 struct thread * 2264 sched_choose(void) 2265 { 2266 #ifdef SMP 2267 struct tdq_group *tdg; 2268 #endif 2269 struct td_sched *ts; 2270 struct tdq *tdq; 2271 2272 tdq = TDQ_SELF(); 2273 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2274 ts = tdq_choose(tdq); 2275 if (ts) { 2276 tdq_runq_rem(tdq, ts); 2277 return (ts->ts_thread); 2278 } 2279 #ifdef SMP 2280 /* 2281 * We only set the idled bit when all of the cpus in the group are 2282 * idle. Otherwise we could get into a situation where a thread bounces 2283 * back and forth between two idle cores on seperate physical CPUs. 2284 */ 2285 tdg = tdq->tdq_group; 2286 tdg->tdg_idlemask |= PCPU_GET(cpumask); 2287 if (tdg->tdg_idlemask == tdg->tdg_cpumask) 2288 atomic_set_int(&tdq_idle, tdg->tdg_mask); 2289 tdq->tdq_lowpri = PRI_MAX_IDLE; 2290 #endif 2291 return (PCPU_GET(idlethread)); 2292 } 2293 2294 /* 2295 * Set owepreempt if necessary. Preemption never happens directly in ULE, 2296 * we always request it once we exit a critical section. 2297 */ 2298 static inline void 2299 sched_setpreempt(struct thread *td) 2300 { 2301 struct thread *ctd; 2302 int cpri; 2303 int pri; 2304 2305 ctd = curthread; 2306 pri = td->td_priority; 2307 cpri = ctd->td_priority; 2308 if (td->td_priority < ctd->td_priority) 2309 curthread->td_flags |= TDF_NEEDRESCHED; 2310 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) 2311 return; 2312 /* 2313 * Always preempt IDLE threads. Otherwise only if the preempting 2314 * thread is an ithread. 2315 */ 2316 if (pri > preempt_thresh && cpri < PRI_MIN_IDLE) 2317 return; 2318 ctd->td_owepreempt = 1; 2319 return; 2320 } 2321 2322 /* 2323 * Add a thread to a thread queue. Initializes priority, slice, runq, and 2324 * add it to the appropriate queue. This is the internal function called 2325 * when the tdq is predetermined. 2326 */ 2327 void 2328 tdq_add(struct tdq *tdq, struct thread *td, int flags) 2329 { 2330 struct td_sched *ts; 2331 int class; 2332 #ifdef SMP 2333 int cpumask; 2334 #endif 2335 2336 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2337 KASSERT((td->td_inhibitors == 0), 2338 ("sched_add: trying to run inhibited thread")); 2339 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 2340 ("sched_add: bad thread state")); 2341 KASSERT(td->td_flags & TDF_INMEM, 2342 ("sched_add: thread swapped out")); 2343 2344 ts = td->td_sched; 2345 class = PRI_BASE(td->td_pri_class); 2346 TD_SET_RUNQ(td); 2347 if (ts->ts_slice == 0) 2348 ts->ts_slice = sched_slice; 2349 /* 2350 * Pick the run queue based on priority. 2351 */ 2352 if (td->td_priority <= PRI_MAX_REALTIME) 2353 ts->ts_runq = &tdq->tdq_realtime; 2354 else if (td->td_priority <= PRI_MAX_TIMESHARE) 2355 ts->ts_runq = &tdq->tdq_timeshare; 2356 else 2357 ts->ts_runq = &tdq->tdq_idle; 2358 #ifdef SMP 2359 cpumask = 1 << ts->ts_cpu; 2360 /* 2361 * If we had been idle, clear our bit in the group and potentially 2362 * the global bitmap. 2363 */ 2364 if ((class != PRI_IDLE && class != PRI_ITHD) && 2365 (tdq->tdq_group->tdg_idlemask & cpumask) != 0) { 2366 /* 2367 * Check to see if our group is unidling, and if so, remove it 2368 * from the global idle mask. 2369 */ 2370 if (tdq->tdq_group->tdg_idlemask == 2371 tdq->tdq_group->tdg_cpumask) 2372 atomic_clear_int(&tdq_idle, tdq->tdq_group->tdg_mask); 2373 /* 2374 * Now remove ourselves from the group specific idle mask. 2375 */ 2376 tdq->tdq_group->tdg_idlemask &= ~cpumask; 2377 } 2378 if (td->td_priority < tdq->tdq_lowpri) 2379 tdq->tdq_lowpri = td->td_priority; 2380 #endif 2381 tdq_runq_add(tdq, ts, flags); 2382 tdq_load_add(tdq, ts); 2383 } 2384 2385 /* 2386 * Select the target thread queue and add a thread to it. Request 2387 * preemption or IPI a remote processor if required. 2388 */ 2389 void 2390 sched_add(struct thread *td, int flags) 2391 { 2392 struct td_sched *ts; 2393 struct tdq *tdq; 2394 #ifdef SMP 2395 int cpuid; 2396 int cpu; 2397 #endif 2398 CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)", 2399 td, td->td_proc->p_comm, td->td_priority, curthread, 2400 curthread->td_proc->p_comm); 2401 THREAD_LOCK_ASSERT(td, MA_OWNED); 2402 ts = td->td_sched; 2403 /* 2404 * Recalculate the priority before we select the target cpu or 2405 * run-queue. 2406 */ 2407 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 2408 sched_priority(td); 2409 #ifdef SMP 2410 cpuid = PCPU_GET(cpuid); 2411 /* 2412 * Pick the destination cpu and if it isn't ours transfer to the 2413 * target cpu. 2414 */ 2415 if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_MIGRATE(td)) 2416 cpu = cpuid; 2417 else if (!THREAD_CAN_MIGRATE(td)) 2418 cpu = ts->ts_cpu; 2419 else 2420 cpu = sched_pickcpu(ts, flags); 2421 tdq = sched_setcpu(ts, cpu, flags); 2422 tdq_add(tdq, td, flags); 2423 if (cpu != cpuid) { 2424 tdq_notify(ts); 2425 return; 2426 } 2427 #else 2428 tdq = TDQ_SELF(); 2429 TDQ_LOCK(tdq); 2430 /* 2431 * Now that the thread is moving to the run-queue, set the lock 2432 * to the scheduler's lock. 2433 */ 2434 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 2435 tdq_add(tdq, td, flags); 2436 #endif 2437 if (!(flags & SRQ_YIELDING)) 2438 sched_setpreempt(td); 2439 } 2440 2441 /* 2442 * Remove a thread from a run-queue without running it. This is used 2443 * when we're stealing a thread from a remote queue. Otherwise all threads 2444 * exit by calling sched_exit_thread() and sched_throw() themselves. 2445 */ 2446 void 2447 sched_rem(struct thread *td) 2448 { 2449 struct tdq *tdq; 2450 struct td_sched *ts; 2451 2452 CTR5(KTR_SCHED, "sched_rem: %p(%s) prio %d by %p(%s)", 2453 td, td->td_proc->p_comm, td->td_priority, curthread, 2454 curthread->td_proc->p_comm); 2455 ts = td->td_sched; 2456 tdq = TDQ_CPU(ts->ts_cpu); 2457 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2458 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2459 KASSERT(TD_ON_RUNQ(td), 2460 ("sched_rem: thread not on run queue")); 2461 tdq_runq_rem(tdq, ts); 2462 tdq_load_rem(tdq, ts); 2463 TD_SET_CAN_RUN(td); 2464 } 2465 2466 /* 2467 * Fetch cpu utilization information. Updates on demand. 2468 */ 2469 fixpt_t 2470 sched_pctcpu(struct thread *td) 2471 { 2472 fixpt_t pctcpu; 2473 struct td_sched *ts; 2474 2475 pctcpu = 0; 2476 ts = td->td_sched; 2477 if (ts == NULL) 2478 return (0); 2479 2480 thread_lock(td); 2481 if (ts->ts_ticks) { 2482 int rtick; 2483 2484 sched_pctcpu_update(ts); 2485 /* How many rtick per second ? */ 2486 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); 2487 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; 2488 } 2489 thread_unlock(td); 2490 2491 return (pctcpu); 2492 } 2493 2494 /* 2495 * Bind a thread to a target cpu. 2496 */ 2497 void 2498 sched_bind(struct thread *td, int cpu) 2499 { 2500 struct td_sched *ts; 2501 2502 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 2503 ts = td->td_sched; 2504 if (ts->ts_flags & TSF_BOUND) 2505 sched_unbind(td); 2506 ts->ts_flags |= TSF_BOUND; 2507 #ifdef SMP 2508 sched_pin(); 2509 if (PCPU_GET(cpuid) == cpu) 2510 return; 2511 ts->ts_cpu = cpu; 2512 /* When we return from mi_switch we'll be on the correct cpu. */ 2513 mi_switch(SW_VOL, NULL); 2514 #endif 2515 } 2516 2517 /* 2518 * Release a bound thread. 2519 */ 2520 void 2521 sched_unbind(struct thread *td) 2522 { 2523 struct td_sched *ts; 2524 2525 THREAD_LOCK_ASSERT(td, MA_OWNED); 2526 ts = td->td_sched; 2527 if ((ts->ts_flags & TSF_BOUND) == 0) 2528 return; 2529 ts->ts_flags &= ~TSF_BOUND; 2530 #ifdef SMP 2531 sched_unpin(); 2532 #endif 2533 } 2534 2535 int 2536 sched_is_bound(struct thread *td) 2537 { 2538 THREAD_LOCK_ASSERT(td, MA_OWNED); 2539 return (td->td_sched->ts_flags & TSF_BOUND); 2540 } 2541 2542 /* 2543 * Basic yield call. 2544 */ 2545 void 2546 sched_relinquish(struct thread *td) 2547 { 2548 thread_lock(td); 2549 SCHED_STAT_INC(switch_relinquish); 2550 mi_switch(SW_VOL, NULL); 2551 thread_unlock(td); 2552 } 2553 2554 /* 2555 * Return the total system load. 2556 */ 2557 int 2558 sched_load(void) 2559 { 2560 #ifdef SMP 2561 int total; 2562 int i; 2563 2564 total = 0; 2565 for (i = 0; i <= tdg_maxid; i++) 2566 total += TDQ_GROUP(i)->tdg_load; 2567 return (total); 2568 #else 2569 return (TDQ_SELF()->tdq_sysload); 2570 #endif 2571 } 2572 2573 int 2574 sched_sizeof_proc(void) 2575 { 2576 return (sizeof(struct proc)); 2577 } 2578 2579 int 2580 sched_sizeof_thread(void) 2581 { 2582 return (sizeof(struct thread) + sizeof(struct td_sched)); 2583 } 2584 2585 /* 2586 * The actual idle process. 2587 */ 2588 void 2589 sched_idletd(void *dummy) 2590 { 2591 struct thread *td; 2592 struct tdq *tdq; 2593 2594 td = curthread; 2595 tdq = TDQ_SELF(); 2596 mtx_assert(&Giant, MA_NOTOWNED); 2597 /* ULE relies on preemption for idle interruption. */ 2598 for (;;) { 2599 #ifdef SMP 2600 if (tdq_idled(tdq)) 2601 cpu_idle(); 2602 #else 2603 cpu_idle(); 2604 #endif 2605 } 2606 } 2607 2608 /* 2609 * A CPU is entering for the first time or a thread is exiting. 2610 */ 2611 void 2612 sched_throw(struct thread *td) 2613 { 2614 struct thread *newtd; 2615 struct tdq *tdq; 2616 2617 tdq = TDQ_SELF(); 2618 if (td == NULL) { 2619 /* Correct spinlock nesting and acquire the correct lock. */ 2620 TDQ_LOCK(tdq); 2621 spinlock_exit(); 2622 } else { 2623 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2624 tdq_load_rem(tdq, td->td_sched); 2625 } 2626 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 2627 newtd = choosethread(); 2628 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 2629 PCPU_SET(switchtime, cpu_ticks()); 2630 PCPU_SET(switchticks, ticks); 2631 cpu_throw(td, newtd); /* doesn't return */ 2632 } 2633 2634 /* 2635 * This is called from fork_exit(). Just acquire the correct locks and 2636 * let fork do the rest of the work. 2637 */ 2638 void 2639 sched_fork_exit(struct thread *td) 2640 { 2641 struct td_sched *ts; 2642 struct tdq *tdq; 2643 int cpuid; 2644 2645 /* 2646 * Finish setting up thread glue so that it begins execution in a 2647 * non-nested critical section with the scheduler lock held. 2648 */ 2649 cpuid = PCPU_GET(cpuid); 2650 tdq = TDQ_CPU(cpuid); 2651 ts = td->td_sched; 2652 if (TD_IS_IDLETHREAD(td)) 2653 td->td_lock = TDQ_LOCKPTR(tdq); 2654 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2655 td->td_oncpu = cpuid; 2656 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 2657 } 2658 2659 static SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, 2660 "Scheduler"); 2661 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0, 2662 "Scheduler name"); 2663 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 2664 "Slice size for timeshare threads"); 2665 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, 2666 "Interactivity score threshold"); 2667 SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh, 2668 0,"Min priority for preemption, lower priorities have greater precedence"); 2669 #ifdef SMP 2670 SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri, CTLFLAG_RW, &pick_pri, 0, 2671 "Pick the target cpu based on priority rather than load."); 2672 SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0, 2673 "Number of hz ticks to keep thread affinity for"); 2674 SYSCTL_INT(_kern_sched, OID_AUTO, tryself, CTLFLAG_RW, &tryself, 0, ""); 2675 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, 2676 "Enables the long-term load balancer"); 2677 SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW, 2678 &balance_interval, 0, 2679 "Average frequency in stathz ticks to run the long-term balancer"); 2680 SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0, 2681 "Steals work from another hyper-threaded core on idle"); 2682 SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0, 2683 "Attempts to steal work from other cores before idling"); 2684 SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0, 2685 "Minimum load on remote cpu before we'll steal"); 2686 SYSCTL_INT(_kern_sched, OID_AUTO, topology, CTLFLAG_RD, &topology, 0, 2687 "True when a topology has been specified by the MD code."); 2688 #endif 2689 2690 /* ps compat. All cpu percentages from ULE are weighted. */ 2691 static int ccpu = 0; 2692 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 2693 2694 2695 #define KERN_SWITCH_INCLUDE 1 2696 #include "kern/kern_switch.c" 2697