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 it's 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 #ifndef PREEMPTION 75 #error "SCHED_ULE requires options PREEMPTION" 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_slptick; /* Tick when we went to sleep. */ 92 int ts_slice; /* Ticks of slice remaining. */ 93 u_int ts_slptime; /* Number of ticks we vol. slept */ 94 u_int ts_runtime; /* Number of ticks we were running */ 95 /* The following variables are only used for pctcpu calculation */ 96 int ts_ltick; /* Last tick that we were running on */ 97 int ts_ftick; /* First tick that we were running on */ 98 int ts_ticks; /* Tick count */ 99 #ifdef SMP 100 int ts_rltick; /* Real last tick, for affinity. */ 101 #endif 102 }; 103 /* flags kept in ts_flags */ 104 #define TSF_BOUND 0x0001 /* Thread can not migrate. */ 105 #define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */ 106 107 static struct td_sched td_sched0; 108 109 /* 110 * Cpu percentage computation macros and defines. 111 * 112 * SCHED_TICK_SECS: Number of seconds to average the cpu usage across. 113 * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across. 114 * SCHED_TICK_MAX: Maximum number of ticks before scaling back. 115 * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results. 116 * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count. 117 * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks. 118 */ 119 #define SCHED_TICK_SECS 10 120 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS) 121 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz) 122 #define SCHED_TICK_SHIFT 10 123 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT) 124 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz)) 125 126 /* 127 * These macros determine priorities for non-interactive threads. They are 128 * assigned a priority based on their recent cpu utilization as expressed 129 * by the ratio of ticks to the tick total. NHALF priorities at the start 130 * and end of the MIN to MAX timeshare range are only reachable with negative 131 * or positive nice respectively. 132 * 133 * PRI_RANGE: Priority range for utilization dependent priorities. 134 * PRI_NRESV: Number of nice values. 135 * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total. 136 * PRI_NICE: Determines the part of the priority inherited from nice. 137 */ 138 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN) 139 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) 140 #define SCHED_PRI_MIN (PRI_MIN_TIMESHARE + SCHED_PRI_NHALF) 141 #define SCHED_PRI_MAX (PRI_MAX_TIMESHARE - SCHED_PRI_NHALF) 142 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN) 143 #define SCHED_PRI_TICKS(ts) \ 144 (SCHED_TICK_HZ((ts)) / \ 145 (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE)) 146 #define SCHED_PRI_NICE(nice) (nice) 147 148 /* 149 * These determine the interactivity of a process. Interactivity differs from 150 * cpu utilization in that it expresses the voluntary time slept vs time ran 151 * while cpu utilization includes all time not running. This more accurately 152 * models the intent of the thread. 153 * 154 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 155 * before throttling back. 156 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. 157 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 158 * INTERACT_THRESH: Threshhold for placement on the current runq. 159 */ 160 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT) 161 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT) 162 #define SCHED_INTERACT_MAX (100) 163 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 164 #define SCHED_INTERACT_THRESH (30) 165 166 /* 167 * tickincr: Converts a stathz tick into a hz domain scaled by 168 * the shift factor. Without the shift the error rate 169 * due to rounding would be unacceptably high. 170 * realstathz: stathz is sometimes 0 and run off of hz. 171 * sched_slice: Runtime of each thread before rescheduling. 172 * preempt_thresh: Priority threshold for preemption and remote IPIs. 173 */ 174 static int sched_interact = SCHED_INTERACT_THRESH; 175 static int realstathz; 176 static int tickincr; 177 static int sched_slice; 178 static int preempt_thresh = PRI_MIN_KERN; 179 180 /* 181 * tdq - per processor runqs and statistics. All fields are protected by the 182 * tdq_lock. The load and lowpri may be accessed without to avoid excess 183 * locking in sched_pickcpu(); 184 */ 185 struct tdq { 186 struct mtx *tdq_lock; /* Pointer to group lock. */ 187 struct runq tdq_realtime; /* real-time run queue. */ 188 struct runq tdq_timeshare; /* timeshare run queue. */ 189 struct runq tdq_idle; /* Queue of IDLE threads. */ 190 int tdq_load; /* Aggregate load. */ 191 u_char tdq_idx; /* Current insert index. */ 192 u_char tdq_ridx; /* Current removal index. */ 193 #ifdef SMP 194 u_char tdq_lowpri; /* Lowest priority thread. */ 195 int tdq_transferable; /* Transferable thread count. */ 196 LIST_ENTRY(tdq) tdq_siblings; /* Next in tdq group. */ 197 struct tdq_group *tdq_group; /* Our processor group. */ 198 #else 199 int tdq_sysload; /* For loadavg, !ITHD load. */ 200 #endif 201 } __aligned(64); 202 203 204 #ifdef SMP 205 /* 206 * tdq groups are groups of processors which can cheaply share threads. When 207 * one processor in the group goes idle it will check the runqs of the other 208 * processors in its group prior to halting and waiting for an interrupt. 209 * These groups are suitable for SMT (Symetric Multi-Threading) and not NUMA. 210 * In a numa environment we'd want an idle bitmap per group and a two tiered 211 * load balancer. 212 */ 213 struct tdq_group { 214 struct mtx tdg_lock; /* Protects all fields below. */ 215 int tdg_cpus; /* Count of CPUs in this tdq group. */ 216 cpumask_t tdg_cpumask; /* Mask of cpus in this group. */ 217 cpumask_t tdg_idlemask; /* Idle cpus in this group. */ 218 cpumask_t tdg_mask; /* Bit mask for first cpu. */ 219 int tdg_load; /* Total load of this group. */ 220 int tdg_transferable; /* Transferable load of this group. */ 221 LIST_HEAD(, tdq) tdg_members; /* Linked list of all members. */ 222 char tdg_name[16]; /* lock name. */ 223 } __aligned(64); 224 225 #define SCHED_AFFINITY_DEFAULT (max(1, hz / 300)) 226 #define SCHED_AFFINITY(ts) ((ts)->ts_rltick > ticks - affinity) 227 228 /* 229 * Run-time tunables. 230 */ 231 static int rebalance = 1; 232 static int balance_secs = 1; 233 static int pick_pri = 1; 234 static int affinity; 235 static int tryself = 1; 236 static int steal_htt = 0; 237 static int steal_idle = 1; 238 static int steal_thresh = 2; 239 static int topology = 0; 240 241 /* 242 * One thread queue per processor. 243 */ 244 static volatile cpumask_t tdq_idle; 245 static int tdg_maxid; 246 static struct tdq tdq_cpu[MAXCPU]; 247 static struct tdq_group tdq_groups[MAXCPU]; 248 static struct callout balco; 249 static struct callout gbalco; 250 251 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)]) 252 #define TDQ_CPU(x) (&tdq_cpu[(x)]) 253 #define TDQ_ID(x) ((int)((x) - tdq_cpu)) 254 #define TDQ_GROUP(x) (&tdq_groups[(x)]) 255 #define TDG_ID(x) ((int)((x) - tdq_groups)) 256 #else /* !SMP */ 257 static struct tdq tdq_cpu; 258 static struct mtx tdq_lock; 259 260 #define TDQ_ID(x) (0) 261 #define TDQ_SELF() (&tdq_cpu) 262 #define TDQ_CPU(x) (&tdq_cpu) 263 #endif 264 265 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type)) 266 #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t))) 267 #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f)) 268 #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t))) 269 #define TDQ_LOCKPTR(t) ((t)->tdq_lock) 270 271 static void sched_priority(struct thread *); 272 static void sched_thread_priority(struct thread *, u_char); 273 static int sched_interact_score(struct thread *); 274 static void sched_interact_update(struct thread *); 275 static void sched_interact_fork(struct thread *); 276 static void sched_pctcpu_update(struct td_sched *); 277 278 /* Operations on per processor queues */ 279 static struct td_sched * tdq_choose(struct tdq *); 280 static void tdq_setup(struct tdq *); 281 static void tdq_load_add(struct tdq *, struct td_sched *); 282 static void tdq_load_rem(struct tdq *, struct td_sched *); 283 static __inline void tdq_runq_add(struct tdq *, struct td_sched *, int); 284 static __inline void tdq_runq_rem(struct tdq *, struct td_sched *); 285 void tdq_print(int cpu); 286 static void runq_print(struct runq *rq); 287 static void tdq_add(struct tdq *, struct thread *, int); 288 #ifdef SMP 289 static void tdq_move(struct tdq *, struct tdq *); 290 static int tdq_idled(struct tdq *); 291 static void tdq_notify(struct td_sched *); 292 static struct td_sched *tdq_steal(struct tdq *, int); 293 static struct td_sched *runq_steal(struct runq *); 294 static int sched_pickcpu(struct td_sched *, int); 295 static void sched_balance(void *); 296 static void sched_balance_groups(void *); 297 static void sched_balance_group(struct tdq_group *); 298 static void sched_balance_pair(struct tdq *, struct tdq *); 299 static inline struct tdq *sched_setcpu(struct td_sched *, int, int); 300 static inline struct mtx *thread_block_switch(struct thread *); 301 static inline void thread_unblock_switch(struct thread *, struct mtx *); 302 static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int); 303 304 #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0) 305 #endif 306 307 static void sched_setup(void *dummy); 308 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL) 309 310 static void sched_initticks(void *dummy); 311 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, NULL) 312 313 /* 314 * Print the threads waiting on a run-queue. 315 */ 316 static void 317 runq_print(struct runq *rq) 318 { 319 struct rqhead *rqh; 320 struct td_sched *ts; 321 int pri; 322 int j; 323 int i; 324 325 for (i = 0; i < RQB_LEN; i++) { 326 printf("\t\trunq bits %d 0x%zx\n", 327 i, rq->rq_status.rqb_bits[i]); 328 for (j = 0; j < RQB_BPW; j++) 329 if (rq->rq_status.rqb_bits[i] & (1ul << j)) { 330 pri = j + (i << RQB_L2BPW); 331 rqh = &rq->rq_queues[pri]; 332 TAILQ_FOREACH(ts, rqh, ts_procq) { 333 printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n", 334 ts->ts_thread, ts->ts_thread->td_proc->p_comm, ts->ts_thread->td_priority, ts->ts_rqindex, pri); 335 } 336 } 337 } 338 } 339 340 /* 341 * Print the status of a per-cpu thread queue. Should be a ddb show cmd. 342 */ 343 void 344 tdq_print(int cpu) 345 { 346 struct tdq *tdq; 347 348 tdq = TDQ_CPU(cpu); 349 350 printf("tdq %d:\n", TDQ_ID(tdq)); 351 printf("\tlockptr %p\n", TDQ_LOCKPTR(tdq)); 352 printf("\tload: %d\n", tdq->tdq_load); 353 printf("\ttimeshare idx: %d\n", tdq->tdq_idx); 354 printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx); 355 printf("\trealtime runq:\n"); 356 runq_print(&tdq->tdq_realtime); 357 printf("\ttimeshare runq:\n"); 358 runq_print(&tdq->tdq_timeshare); 359 printf("\tidle runq:\n"); 360 runq_print(&tdq->tdq_idle); 361 #ifdef SMP 362 printf("\tload transferable: %d\n", tdq->tdq_transferable); 363 printf("\tlowest priority: %d\n", tdq->tdq_lowpri); 364 printf("\tgroup: %d\n", TDG_ID(tdq->tdq_group)); 365 printf("\tLock name: %s\n", tdq->tdq_group->tdg_name); 366 #endif 367 } 368 369 #define TS_RQ_PPQ (((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS) 370 /* 371 * Add a thread to the actual run-queue. Keeps transferable counts up to 372 * date with what is actually on the run-queue. Selects the correct 373 * queue position for timeshare threads. 374 */ 375 static __inline void 376 tdq_runq_add(struct tdq *tdq, struct td_sched *ts, int flags) 377 { 378 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 379 THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); 380 #ifdef SMP 381 if (THREAD_CAN_MIGRATE(ts->ts_thread)) { 382 tdq->tdq_transferable++; 383 tdq->tdq_group->tdg_transferable++; 384 ts->ts_flags |= TSF_XFERABLE; 385 } 386 #endif 387 if (ts->ts_runq == &tdq->tdq_timeshare) { 388 u_char pri; 389 390 pri = ts->ts_thread->td_priority; 391 KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE, 392 ("Invalid priority %d on timeshare runq", pri)); 393 /* 394 * This queue contains only priorities between MIN and MAX 395 * realtime. Use the whole queue to represent these values. 396 */ 397 if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) { 398 pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ; 399 pri = (pri + tdq->tdq_idx) % RQ_NQS; 400 /* 401 * This effectively shortens the queue by one so we 402 * can have a one slot difference between idx and 403 * ridx while we wait for threads to drain. 404 */ 405 if (tdq->tdq_ridx != tdq->tdq_idx && 406 pri == tdq->tdq_ridx) 407 pri = (unsigned char)(pri - 1) % RQ_NQS; 408 } else 409 pri = tdq->tdq_ridx; 410 runq_add_pri(ts->ts_runq, ts, pri, flags); 411 } else 412 runq_add(ts->ts_runq, ts, flags); 413 } 414 415 /* 416 * Remove a thread from a run-queue. This typically happens when a thread 417 * is selected to run. Running threads are not on the queue and the 418 * transferable count does not reflect them. 419 */ 420 static __inline void 421 tdq_runq_rem(struct tdq *tdq, struct td_sched *ts) 422 { 423 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 424 KASSERT(ts->ts_runq != NULL, 425 ("tdq_runq_remove: thread %p null ts_runq", ts->ts_thread)); 426 #ifdef SMP 427 if (ts->ts_flags & TSF_XFERABLE) { 428 tdq->tdq_transferable--; 429 tdq->tdq_group->tdg_transferable--; 430 ts->ts_flags &= ~TSF_XFERABLE; 431 } 432 #endif 433 if (ts->ts_runq == &tdq->tdq_timeshare) { 434 if (tdq->tdq_idx != tdq->tdq_ridx) 435 runq_remove_idx(ts->ts_runq, ts, &tdq->tdq_ridx); 436 else 437 runq_remove_idx(ts->ts_runq, ts, NULL); 438 /* 439 * For timeshare threads we update the priority here so 440 * the priority reflects the time we've been sleeping. 441 */ 442 ts->ts_ltick = ticks; 443 sched_pctcpu_update(ts); 444 sched_priority(ts->ts_thread); 445 } else 446 runq_remove(ts->ts_runq, ts); 447 } 448 449 /* 450 * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load 451 * for this thread to the referenced thread queue. 452 */ 453 static void 454 tdq_load_add(struct tdq *tdq, struct td_sched *ts) 455 { 456 int class; 457 458 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 459 THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); 460 class = PRI_BASE(ts->ts_thread->td_pri_class); 461 tdq->tdq_load++; 462 CTR2(KTR_SCHED, "cpu %d load: %d", TDQ_ID(tdq), tdq->tdq_load); 463 if (class != PRI_ITHD && 464 (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0) 465 #ifdef SMP 466 tdq->tdq_group->tdg_load++; 467 #else 468 tdq->tdq_sysload++; 469 #endif 470 } 471 472 /* 473 * Remove the load from a thread that is transitioning to a sleep state or 474 * exiting. 475 */ 476 static void 477 tdq_load_rem(struct tdq *tdq, struct td_sched *ts) 478 { 479 int class; 480 481 THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); 482 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 483 class = PRI_BASE(ts->ts_thread->td_pri_class); 484 if (class != PRI_ITHD && 485 (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0) 486 #ifdef SMP 487 tdq->tdq_group->tdg_load--; 488 #else 489 tdq->tdq_sysload--; 490 #endif 491 KASSERT(tdq->tdq_load != 0, 492 ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq))); 493 tdq->tdq_load--; 494 CTR1(KTR_SCHED, "load: %d", tdq->tdq_load); 495 ts->ts_runq = NULL; 496 } 497 498 #ifdef SMP 499 /* 500 * sched_balance is a simple CPU load balancing algorithm. It operates by 501 * finding the least loaded and most loaded cpu and equalizing their load 502 * by migrating some processes. 503 * 504 * Dealing only with two CPUs at a time has two advantages. Firstly, most 505 * installations will only have 2 cpus. Secondly, load balancing too much at 506 * once can have an unpleasant effect on the system. The scheduler rarely has 507 * enough information to make perfect decisions. So this algorithm chooses 508 * simplicity and more gradual effects on load in larger systems. 509 * 510 */ 511 static void 512 sched_balance(void *arg) 513 { 514 struct tdq_group *high; 515 struct tdq_group *low; 516 struct tdq_group *tdg; 517 int cnt; 518 int i; 519 520 callout_reset(&balco, max(hz / 2, random() % (hz * balance_secs)), 521 sched_balance, NULL); 522 if (smp_started == 0 || rebalance == 0) 523 return; 524 low = high = NULL; 525 i = random() % (tdg_maxid + 1); 526 for (cnt = 0; cnt <= tdg_maxid; cnt++) { 527 tdg = TDQ_GROUP(i); 528 /* 529 * Find the CPU with the highest load that has some 530 * threads to transfer. 531 */ 532 if ((high == NULL || tdg->tdg_load > high->tdg_load) 533 && tdg->tdg_transferable) 534 high = tdg; 535 if (low == NULL || tdg->tdg_load < low->tdg_load) 536 low = tdg; 537 if (++i > tdg_maxid) 538 i = 0; 539 } 540 if (low != NULL && high != NULL && high != low) 541 sched_balance_pair(LIST_FIRST(&high->tdg_members), 542 LIST_FIRST(&low->tdg_members)); 543 } 544 545 /* 546 * Balance load between CPUs in a group. Will only migrate within the group. 547 */ 548 static void 549 sched_balance_groups(void *arg) 550 { 551 int i; 552 553 callout_reset(&gbalco, max(hz / 2, random() % (hz * balance_secs)), 554 sched_balance_groups, NULL); 555 if (smp_started == 0 || rebalance == 0) 556 return; 557 for (i = 0; i <= tdg_maxid; i++) 558 sched_balance_group(TDQ_GROUP(i)); 559 } 560 561 /* 562 * Finds the greatest imbalance between two tdqs in a group. 563 */ 564 static void 565 sched_balance_group(struct tdq_group *tdg) 566 { 567 struct tdq *tdq; 568 struct tdq *high; 569 struct tdq *low; 570 int load; 571 572 if (tdg->tdg_transferable == 0) 573 return; 574 low = NULL; 575 high = NULL; 576 LIST_FOREACH(tdq, &tdg->tdg_members, tdq_siblings) { 577 load = tdq->tdq_load; 578 if (high == NULL || load > high->tdq_load) 579 high = tdq; 580 if (low == NULL || load < low->tdq_load) 581 low = tdq; 582 } 583 if (high != NULL && low != NULL && high != low) 584 sched_balance_pair(high, low); 585 } 586 587 /* 588 * Lock two thread queues using their address to maintain lock order. 589 */ 590 static void 591 tdq_lock_pair(struct tdq *one, struct tdq *two) 592 { 593 if (one < two) { 594 TDQ_LOCK(one); 595 TDQ_LOCK_FLAGS(two, MTX_DUPOK); 596 } else { 597 TDQ_LOCK(two); 598 TDQ_LOCK_FLAGS(one, MTX_DUPOK); 599 } 600 } 601 602 /* 603 * Transfer load between two imbalanced thread queues. 604 */ 605 static void 606 sched_balance_pair(struct tdq *high, struct tdq *low) 607 { 608 int transferable; 609 int high_load; 610 int low_load; 611 int move; 612 int diff; 613 int i; 614 615 tdq_lock_pair(high, low); 616 /* 617 * If we're transfering within a group we have to use this specific 618 * tdq's transferable count, otherwise we can steal from other members 619 * of the group. 620 */ 621 if (high->tdq_group == low->tdq_group) { 622 transferable = high->tdq_transferable; 623 high_load = high->tdq_load; 624 low_load = low->tdq_load; 625 } else { 626 transferable = high->tdq_group->tdg_transferable; 627 high_load = high->tdq_group->tdg_load; 628 low_load = low->tdq_group->tdg_load; 629 } 630 /* 631 * Determine what the imbalance is and then adjust that to how many 632 * threads we actually have to give up (transferable). 633 */ 634 if (transferable != 0) { 635 diff = high_load - low_load; 636 move = diff / 2; 637 if (diff & 0x1) 638 move++; 639 move = min(move, transferable); 640 for (i = 0; i < move; i++) 641 tdq_move(high, low); 642 } 643 TDQ_UNLOCK(high); 644 TDQ_UNLOCK(low); 645 return; 646 } 647 648 /* 649 * Move a thread from one thread queue to another. 650 */ 651 static void 652 tdq_move(struct tdq *from, struct tdq *to) 653 { 654 struct td_sched *ts; 655 struct thread *td; 656 struct tdq *tdq; 657 int cpu; 658 659 tdq = from; 660 cpu = TDQ_ID(to); 661 ts = tdq_steal(tdq, 1); 662 if (ts == NULL) { 663 struct tdq_group *tdg; 664 665 tdg = tdq->tdq_group; 666 LIST_FOREACH(tdq, &tdg->tdg_members, tdq_siblings) { 667 if (tdq == from || tdq->tdq_transferable == 0) 668 continue; 669 ts = tdq_steal(tdq, 1); 670 break; 671 } 672 if (ts == NULL) 673 return; 674 } 675 if (tdq == to) 676 return; 677 td = ts->ts_thread; 678 /* 679 * Although the run queue is locked the thread may be blocked. Lock 680 * it to clear this. 681 */ 682 thread_lock(td); 683 /* Drop recursive lock on from. */ 684 TDQ_UNLOCK(from); 685 sched_rem(td); 686 ts->ts_cpu = cpu; 687 td->td_lock = TDQ_LOCKPTR(to); 688 tdq_add(to, td, SRQ_YIELDING); 689 tdq_notify(ts); 690 } 691 692 /* 693 * This tdq has idled. Try to steal a thread from another cpu and switch 694 * to it. 695 */ 696 static int 697 tdq_idled(struct tdq *tdq) 698 { 699 struct tdq_group *tdg; 700 struct tdq *steal; 701 struct td_sched *ts; 702 struct thread *td; 703 int highload; 704 int highcpu; 705 int load; 706 int cpu; 707 708 /* We don't want to be preempted while we're iterating over tdqs */ 709 spinlock_enter(); 710 tdg = tdq->tdq_group; 711 /* 712 * If we're in a cpu group, try and steal threads from another cpu in 713 * the group before idling. 714 */ 715 if (steal_htt && tdg->tdg_cpus > 1 && tdg->tdg_transferable) { 716 LIST_FOREACH(steal, &tdg->tdg_members, tdq_siblings) { 717 if (steal == tdq || steal->tdq_transferable == 0) 718 continue; 719 TDQ_LOCK(steal); 720 ts = tdq_steal(steal, 0); 721 if (ts) 722 goto steal; 723 TDQ_UNLOCK(steal); 724 } 725 } 726 for (;;) { 727 if (steal_idle == 0) 728 break; 729 highcpu = 0; 730 highload = 0; 731 for (cpu = 0; cpu <= mp_maxid; cpu++) { 732 if (CPU_ABSENT(cpu)) 733 continue; 734 steal = TDQ_CPU(cpu); 735 load = TDQ_CPU(cpu)->tdq_transferable; 736 if (load < highload) 737 continue; 738 highload = load; 739 highcpu = cpu; 740 } 741 if (highload < steal_thresh) 742 break; 743 steal = TDQ_CPU(highcpu); 744 TDQ_LOCK(steal); 745 if (steal->tdq_transferable >= steal_thresh && 746 (ts = tdq_steal(steal, 1)) != NULL) 747 goto steal; 748 TDQ_UNLOCK(steal); 749 break; 750 } 751 spinlock_exit(); 752 return (1); 753 steal: 754 td = ts->ts_thread; 755 thread_lock(td); 756 spinlock_exit(); 757 MPASS(td->td_lock == TDQ_LOCKPTR(steal)); 758 TDQ_UNLOCK(steal); 759 sched_rem(td); 760 sched_setcpu(ts, PCPU_GET(cpuid), SRQ_YIELDING); 761 tdq_add(tdq, td, SRQ_YIELDING); 762 MPASS(td->td_lock == curthread->td_lock); 763 mi_switch(SW_VOL, NULL); 764 thread_unlock(curthread); 765 766 return (0); 767 } 768 769 /* 770 * Notify a remote cpu of new work. Sends an IPI if criteria are met. 771 */ 772 static void 773 tdq_notify(struct td_sched *ts) 774 { 775 struct thread *ctd; 776 struct pcpu *pcpu; 777 int cpri; 778 int pri; 779 int cpu; 780 781 cpu = ts->ts_cpu; 782 pri = ts->ts_thread->td_priority; 783 pcpu = pcpu_find(cpu); 784 ctd = pcpu->pc_curthread; 785 cpri = ctd->td_priority; 786 787 /* 788 * If our priority is not better than the current priority there is 789 * nothing to do. 790 */ 791 if (pri > cpri) 792 return; 793 /* 794 * Always IPI idle. 795 */ 796 if (cpri > PRI_MIN_IDLE) 797 goto sendipi; 798 /* 799 * If we're realtime or better and there is timeshare or worse running 800 * send an IPI. 801 */ 802 if (pri < PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME) 803 goto sendipi; 804 /* 805 * Otherwise only IPI if we exceed the threshold. 806 */ 807 if (pri > preempt_thresh) 808 return; 809 sendipi: 810 ctd->td_flags |= TDF_NEEDRESCHED; 811 ipi_selected(1 << cpu, IPI_PREEMPT); 812 } 813 814 /* 815 * Steals load from a timeshare queue. Honors the rotating queue head 816 * index. 817 */ 818 static struct td_sched * 819 runq_steal_from(struct runq *rq, u_char start) 820 { 821 struct td_sched *ts; 822 struct rqbits *rqb; 823 struct rqhead *rqh; 824 int first; 825 int bit; 826 int pri; 827 int i; 828 829 rqb = &rq->rq_status; 830 bit = start & (RQB_BPW -1); 831 pri = 0; 832 first = 0; 833 again: 834 for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) { 835 if (rqb->rqb_bits[i] == 0) 836 continue; 837 if (bit != 0) { 838 for (pri = bit; pri < RQB_BPW; pri++) 839 if (rqb->rqb_bits[i] & (1ul << pri)) 840 break; 841 if (pri >= RQB_BPW) 842 continue; 843 } else 844 pri = RQB_FFS(rqb->rqb_bits[i]); 845 pri += (i << RQB_L2BPW); 846 rqh = &rq->rq_queues[pri]; 847 TAILQ_FOREACH(ts, rqh, ts_procq) { 848 if (first && THREAD_CAN_MIGRATE(ts->ts_thread)) 849 return (ts); 850 first = 1; 851 } 852 } 853 if (start != 0) { 854 start = 0; 855 goto again; 856 } 857 858 return (NULL); 859 } 860 861 /* 862 * Steals load from a standard linear queue. 863 */ 864 static struct td_sched * 865 runq_steal(struct runq *rq) 866 { 867 struct rqhead *rqh; 868 struct rqbits *rqb; 869 struct td_sched *ts; 870 int word; 871 int bit; 872 873 rqb = &rq->rq_status; 874 for (word = 0; word < RQB_LEN; word++) { 875 if (rqb->rqb_bits[word] == 0) 876 continue; 877 for (bit = 0; bit < RQB_BPW; bit++) { 878 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) 879 continue; 880 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; 881 TAILQ_FOREACH(ts, rqh, ts_procq) 882 if (THREAD_CAN_MIGRATE(ts->ts_thread)) 883 return (ts); 884 } 885 } 886 return (NULL); 887 } 888 889 /* 890 * Attempt to steal a thread in priority order from a thread queue. 891 */ 892 static struct td_sched * 893 tdq_steal(struct tdq *tdq, int stealidle) 894 { 895 struct td_sched *ts; 896 897 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 898 if ((ts = runq_steal(&tdq->tdq_realtime)) != NULL) 899 return (ts); 900 if ((ts = runq_steal_from(&tdq->tdq_timeshare, tdq->tdq_ridx)) != NULL) 901 return (ts); 902 if (stealidle) 903 return (runq_steal(&tdq->tdq_idle)); 904 return (NULL); 905 } 906 907 /* 908 * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the 909 * current lock and returns with the assigned queue locked. If this is 910 * via sched_switch() we leave the thread in a blocked state as an 911 * optimization. 912 */ 913 static inline struct tdq * 914 sched_setcpu(struct td_sched *ts, int cpu, int flags) 915 { 916 struct thread *td; 917 struct tdq *tdq; 918 919 THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); 920 921 tdq = TDQ_CPU(cpu); 922 td = ts->ts_thread; 923 ts->ts_cpu = cpu; 924 925 /* If the lock matches just return the queue. */ 926 if (td->td_lock == TDQ_LOCKPTR(tdq)) 927 return (tdq); 928 #ifdef notyet 929 /* 930 * If the thread isn't running it's lockptr is a 931 * turnstile or a sleepqueue. We can just lock_set without 932 * blocking. 933 */ 934 if (TD_CAN_RUN(td)) { 935 TDQ_LOCK(tdq); 936 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 937 return (tdq); 938 } 939 #endif 940 /* 941 * The hard case, migration, we need to block the thread first to 942 * prevent order reversals with other cpus locks. 943 */ 944 thread_lock_block(td); 945 TDQ_LOCK(tdq); 946 thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); 947 return (tdq); 948 } 949 950 /* 951 * Find the thread queue running the lowest priority thread. 952 */ 953 static int 954 tdq_lowestpri(void) 955 { 956 struct tdq *tdq; 957 int lowpri; 958 int lowcpu; 959 int lowload; 960 int load; 961 int cpu; 962 int pri; 963 964 lowload = 0; 965 lowpri = lowcpu = 0; 966 for (cpu = 0; cpu <= mp_maxid; cpu++) { 967 if (CPU_ABSENT(cpu)) 968 continue; 969 tdq = TDQ_CPU(cpu); 970 pri = tdq->tdq_lowpri; 971 load = TDQ_CPU(cpu)->tdq_load; 972 CTR4(KTR_ULE, 973 "cpu %d pri %d lowcpu %d lowpri %d", 974 cpu, pri, lowcpu, lowpri); 975 if (pri < lowpri) 976 continue; 977 if (lowpri && lowpri == pri && load > lowload) 978 continue; 979 lowpri = pri; 980 lowcpu = cpu; 981 lowload = load; 982 } 983 984 return (lowcpu); 985 } 986 987 /* 988 * Find the thread queue with the least load. 989 */ 990 static int 991 tdq_lowestload(void) 992 { 993 struct tdq *tdq; 994 int lowload; 995 int lowpri; 996 int lowcpu; 997 int load; 998 int cpu; 999 int pri; 1000 1001 lowcpu = 0; 1002 lowload = TDQ_CPU(0)->tdq_load; 1003 lowpri = TDQ_CPU(0)->tdq_lowpri; 1004 for (cpu = 1; cpu <= mp_maxid; cpu++) { 1005 if (CPU_ABSENT(cpu)) 1006 continue; 1007 tdq = TDQ_CPU(cpu); 1008 load = tdq->tdq_load; 1009 pri = tdq->tdq_lowpri; 1010 CTR4(KTR_ULE, "cpu %d load %d lowcpu %d lowload %d", 1011 cpu, load, lowcpu, lowload); 1012 if (load > lowload) 1013 continue; 1014 if (load == lowload && pri < lowpri) 1015 continue; 1016 lowcpu = cpu; 1017 lowload = load; 1018 lowpri = pri; 1019 } 1020 1021 return (lowcpu); 1022 } 1023 1024 /* 1025 * Pick the destination cpu for sched_add(). Respects affinity and makes 1026 * a determination based on load or priority of available processors. 1027 */ 1028 static int 1029 sched_pickcpu(struct td_sched *ts, int flags) 1030 { 1031 struct tdq *tdq; 1032 int self; 1033 int pri; 1034 int cpu; 1035 1036 cpu = self = PCPU_GET(cpuid); 1037 if (smp_started == 0) 1038 return (self); 1039 /* 1040 * Don't migrate a running thread from sched_switch(). 1041 */ 1042 if (flags & SRQ_OURSELF) { 1043 CTR1(KTR_ULE, "YIELDING %d", 1044 curthread->td_priority); 1045 return (self); 1046 } 1047 pri = ts->ts_thread->td_priority; 1048 cpu = ts->ts_cpu; 1049 /* 1050 * Regardless of affinity, if the last cpu is idle send it there. 1051 */ 1052 tdq = TDQ_CPU(cpu); 1053 if (tdq->tdq_lowpri > PRI_MIN_IDLE) { 1054 CTR5(KTR_ULE, 1055 "ts_cpu %d idle, ltick %d ticks %d pri %d curthread %d", 1056 ts->ts_cpu, ts->ts_rltick, ticks, pri, 1057 tdq->tdq_lowpri); 1058 return (ts->ts_cpu); 1059 } 1060 /* 1061 * If we have affinity, try to place it on the cpu we last ran on. 1062 */ 1063 if (SCHED_AFFINITY(ts) && tdq->tdq_lowpri > pri) { 1064 CTR5(KTR_ULE, 1065 "affinity for %d, ltick %d ticks %d pri %d curthread %d", 1066 ts->ts_cpu, ts->ts_rltick, ticks, pri, 1067 tdq->tdq_lowpri); 1068 return (ts->ts_cpu); 1069 } 1070 /* 1071 * Look for an idle group. 1072 */ 1073 CTR1(KTR_ULE, "tdq_idle %X", tdq_idle); 1074 cpu = ffs(tdq_idle); 1075 if (cpu) 1076 return (--cpu); 1077 /* 1078 * If there are no idle cores see if we can run the thread locally. This may 1079 * improve locality among sleepers and wakers when there is shared data. 1080 */ 1081 if (tryself && pri < curthread->td_priority) { 1082 CTR1(KTR_ULE, "tryself %d", 1083 curthread->td_priority); 1084 return (self); 1085 } 1086 /* 1087 * Now search for the cpu running the lowest priority thread with 1088 * the least load. 1089 */ 1090 if (pick_pri) 1091 cpu = tdq_lowestpri(); 1092 else 1093 cpu = tdq_lowestload(); 1094 return (cpu); 1095 } 1096 1097 #endif /* SMP */ 1098 1099 /* 1100 * Pick the highest priority task we have and return it. 1101 */ 1102 static struct td_sched * 1103 tdq_choose(struct tdq *tdq) 1104 { 1105 struct td_sched *ts; 1106 1107 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1108 ts = runq_choose(&tdq->tdq_realtime); 1109 if (ts != NULL) 1110 return (ts); 1111 ts = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); 1112 if (ts != NULL) { 1113 KASSERT(ts->ts_thread->td_priority >= PRI_MIN_TIMESHARE, 1114 ("tdq_choose: Invalid priority on timeshare queue %d", 1115 ts->ts_thread->td_priority)); 1116 return (ts); 1117 } 1118 1119 ts = runq_choose(&tdq->tdq_idle); 1120 if (ts != NULL) { 1121 KASSERT(ts->ts_thread->td_priority >= PRI_MIN_IDLE, 1122 ("tdq_choose: Invalid priority on idle queue %d", 1123 ts->ts_thread->td_priority)); 1124 return (ts); 1125 } 1126 1127 return (NULL); 1128 } 1129 1130 /* 1131 * Initialize a thread queue. 1132 */ 1133 static void 1134 tdq_setup(struct tdq *tdq) 1135 { 1136 1137 if (bootverbose) 1138 printf("ULE: setup cpu %d\n", TDQ_ID(tdq)); 1139 runq_init(&tdq->tdq_realtime); 1140 runq_init(&tdq->tdq_timeshare); 1141 runq_init(&tdq->tdq_idle); 1142 tdq->tdq_load = 0; 1143 } 1144 1145 #ifdef SMP 1146 static void 1147 tdg_setup(struct tdq_group *tdg) 1148 { 1149 if (bootverbose) 1150 printf("ULE: setup cpu group %d\n", TDG_ID(tdg)); 1151 snprintf(tdg->tdg_name, sizeof(tdg->tdg_name), 1152 "sched lock %d", (int)TDG_ID(tdg)); 1153 mtx_init(&tdg->tdg_lock, tdg->tdg_name, "sched lock", 1154 MTX_SPIN | MTX_RECURSE); 1155 LIST_INIT(&tdg->tdg_members); 1156 tdg->tdg_load = 0; 1157 tdg->tdg_transferable = 0; 1158 tdg->tdg_cpus = 0; 1159 tdg->tdg_mask = 0; 1160 tdg->tdg_cpumask = 0; 1161 tdg->tdg_idlemask = 0; 1162 } 1163 1164 static void 1165 tdg_add(struct tdq_group *tdg, struct tdq *tdq) 1166 { 1167 if (tdg->tdg_mask == 0) 1168 tdg->tdg_mask |= 1 << TDQ_ID(tdq); 1169 tdg->tdg_cpumask |= 1 << TDQ_ID(tdq); 1170 tdg->tdg_cpus++; 1171 tdq->tdq_group = tdg; 1172 tdq->tdq_lock = &tdg->tdg_lock; 1173 LIST_INSERT_HEAD(&tdg->tdg_members, tdq, tdq_siblings); 1174 if (bootverbose) 1175 printf("ULE: adding cpu %d to group %d: cpus %d mask 0x%X\n", 1176 TDQ_ID(tdq), TDG_ID(tdg), tdg->tdg_cpus, tdg->tdg_cpumask); 1177 } 1178 1179 static void 1180 sched_setup_topology(void) 1181 { 1182 struct tdq_group *tdg; 1183 struct cpu_group *cg; 1184 int balance_groups; 1185 struct tdq *tdq; 1186 int i; 1187 int j; 1188 1189 topology = 1; 1190 balance_groups = 0; 1191 for (i = 0; i < smp_topology->ct_count; i++) { 1192 cg = &smp_topology->ct_group[i]; 1193 tdg = &tdq_groups[i]; 1194 /* 1195 * Initialize the group. 1196 */ 1197 tdg_setup(tdg); 1198 /* 1199 * Find all of the group members and add them. 1200 */ 1201 for (j = 0; j < MAXCPU; j++) { 1202 if ((cg->cg_mask & (1 << j)) != 0) { 1203 tdq = TDQ_CPU(j); 1204 tdq_setup(tdq); 1205 tdg_add(tdg, tdq); 1206 } 1207 } 1208 if (tdg->tdg_cpus > 1) 1209 balance_groups = 1; 1210 } 1211 tdg_maxid = smp_topology->ct_count - 1; 1212 if (balance_groups) 1213 sched_balance_groups(NULL); 1214 } 1215 1216 static void 1217 sched_setup_smp(void) 1218 { 1219 struct tdq_group *tdg; 1220 struct tdq *tdq; 1221 int cpus; 1222 int i; 1223 1224 for (cpus = 0, i = 0; i < MAXCPU; i++) { 1225 if (CPU_ABSENT(i)) 1226 continue; 1227 tdq = &tdq_cpu[i]; 1228 tdg = &tdq_groups[i]; 1229 /* 1230 * Setup a tdq group with one member. 1231 */ 1232 tdg_setup(tdg); 1233 tdq_setup(tdq); 1234 tdg_add(tdg, tdq); 1235 cpus++; 1236 } 1237 tdg_maxid = cpus - 1; 1238 } 1239 1240 /* 1241 * Fake a topology with one group containing all CPUs. 1242 */ 1243 static void 1244 sched_fake_topo(void) 1245 { 1246 #ifdef SCHED_FAKE_TOPOLOGY 1247 static struct cpu_top top; 1248 static struct cpu_group group; 1249 1250 top.ct_count = 1; 1251 top.ct_group = &group; 1252 group.cg_mask = all_cpus; 1253 group.cg_count = mp_ncpus; 1254 group.cg_children = 0; 1255 smp_topology = ⊤ 1256 #endif 1257 } 1258 #endif 1259 1260 /* 1261 * Setup the thread queues and initialize the topology based on MD 1262 * information. 1263 */ 1264 static void 1265 sched_setup(void *dummy) 1266 { 1267 struct tdq *tdq; 1268 1269 tdq = TDQ_SELF(); 1270 #ifdef SMP 1271 /* 1272 * Initialize long-term cpu balancing algorithm. 1273 */ 1274 callout_init(&balco, CALLOUT_MPSAFE); 1275 callout_init(&gbalco, CALLOUT_MPSAFE); 1276 sched_fake_topo(); 1277 /* 1278 * Setup tdqs based on a topology configuration or vanilla SMP based 1279 * on mp_maxid. 1280 */ 1281 if (smp_topology == NULL) 1282 sched_setup_smp(); 1283 else 1284 sched_setup_topology(); 1285 sched_balance(NULL); 1286 #else 1287 tdq_setup(tdq); 1288 mtx_init(&tdq_lock, "sched lock", "sched lock", MTX_SPIN | MTX_RECURSE); 1289 tdq->tdq_lock = &tdq_lock; 1290 #endif 1291 /* 1292 * To avoid divide-by-zero, we set realstathz a dummy value 1293 * in case which sched_clock() called before sched_initticks(). 1294 */ 1295 realstathz = hz; 1296 sched_slice = (realstathz/10); /* ~100ms */ 1297 tickincr = 1 << SCHED_TICK_SHIFT; 1298 1299 /* Add thread0's load since it's running. */ 1300 TDQ_LOCK(tdq); 1301 thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1302 tdq_load_add(tdq, &td_sched0); 1303 TDQ_UNLOCK(tdq); 1304 } 1305 1306 /* 1307 * This routine determines the tickincr after stathz and hz are setup. 1308 */ 1309 /* ARGSUSED */ 1310 static void 1311 sched_initticks(void *dummy) 1312 { 1313 int incr; 1314 1315 realstathz = stathz ? stathz : hz; 1316 sched_slice = (realstathz/10); /* ~100ms */ 1317 1318 /* 1319 * tickincr is shifted out by 10 to avoid rounding errors due to 1320 * hz not being evenly divisible by stathz on all platforms. 1321 */ 1322 incr = (hz << SCHED_TICK_SHIFT) / realstathz; 1323 /* 1324 * This does not work for values of stathz that are more than 1325 * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen. 1326 */ 1327 if (incr == 0) 1328 incr = 1; 1329 tickincr = incr; 1330 #ifdef SMP 1331 /* 1332 * Set steal thresh to log2(mp_ncpu) but no greater than 4. This 1333 * prevents excess thrashing on large machines and excess idle on 1334 * smaller machines. 1335 */ 1336 steal_thresh = min(ffs(mp_ncpus) - 1, 4); 1337 affinity = SCHED_AFFINITY_DEFAULT; 1338 #endif 1339 } 1340 1341 1342 /* 1343 * This is the core of the interactivity algorithm. Determines a score based 1344 * on past behavior. It is the ratio of sleep time to run time scaled to 1345 * a [0, 100] integer. This is the voluntary sleep time of a process, which 1346 * differs from the cpu usage because it does not account for time spent 1347 * waiting on a run-queue. Would be prettier if we had floating point. 1348 */ 1349 static int 1350 sched_interact_score(struct thread *td) 1351 { 1352 struct td_sched *ts; 1353 int div; 1354 1355 ts = td->td_sched; 1356 /* 1357 * The score is only needed if this is likely to be an interactive 1358 * task. Don't go through the expense of computing it if there's 1359 * no chance. 1360 */ 1361 if (sched_interact <= SCHED_INTERACT_HALF && 1362 ts->ts_runtime >= ts->ts_slptime) 1363 return (SCHED_INTERACT_HALF); 1364 1365 if (ts->ts_runtime > ts->ts_slptime) { 1366 div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF); 1367 return (SCHED_INTERACT_HALF + 1368 (SCHED_INTERACT_HALF - (ts->ts_slptime / div))); 1369 } 1370 if (ts->ts_slptime > ts->ts_runtime) { 1371 div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF); 1372 return (ts->ts_runtime / div); 1373 } 1374 /* runtime == slptime */ 1375 if (ts->ts_runtime) 1376 return (SCHED_INTERACT_HALF); 1377 1378 /* 1379 * This can happen if slptime and runtime are 0. 1380 */ 1381 return (0); 1382 1383 } 1384 1385 /* 1386 * Scale the scheduling priority according to the "interactivity" of this 1387 * process. 1388 */ 1389 static void 1390 sched_priority(struct thread *td) 1391 { 1392 int score; 1393 int pri; 1394 1395 if (td->td_pri_class != PRI_TIMESHARE) 1396 return; 1397 /* 1398 * If the score is interactive we place the thread in the realtime 1399 * queue with a priority that is less than kernel and interrupt 1400 * priorities. These threads are not subject to nice restrictions. 1401 * 1402 * Scores greater than this are placed on the normal timeshare queue 1403 * where the priority is partially decided by the most recent cpu 1404 * utilization and the rest is decided by nice value. 1405 */ 1406 score = sched_interact_score(td); 1407 if (score < sched_interact) { 1408 pri = PRI_MIN_REALTIME; 1409 pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME) / sched_interact) 1410 * score; 1411 KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME, 1412 ("sched_priority: invalid interactive priority %d score %d", 1413 pri, score)); 1414 } else { 1415 pri = SCHED_PRI_MIN; 1416 if (td->td_sched->ts_ticks) 1417 pri += SCHED_PRI_TICKS(td->td_sched); 1418 pri += SCHED_PRI_NICE(td->td_proc->p_nice); 1419 KASSERT(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE, 1420 ("sched_priority: invalid priority %d: nice %d, " 1421 "ticks %d ftick %d ltick %d tick pri %d", 1422 pri, td->td_proc->p_nice, td->td_sched->ts_ticks, 1423 td->td_sched->ts_ftick, td->td_sched->ts_ltick, 1424 SCHED_PRI_TICKS(td->td_sched))); 1425 } 1426 sched_user_prio(td, pri); 1427 1428 return; 1429 } 1430 1431 /* 1432 * This routine enforces a maximum limit on the amount of scheduling history 1433 * kept. It is called after either the slptime or runtime is adjusted. This 1434 * function is ugly due to integer math. 1435 */ 1436 static void 1437 sched_interact_update(struct thread *td) 1438 { 1439 struct td_sched *ts; 1440 u_int sum; 1441 1442 ts = td->td_sched; 1443 sum = ts->ts_runtime + ts->ts_slptime; 1444 if (sum < SCHED_SLP_RUN_MAX) 1445 return; 1446 /* 1447 * This only happens from two places: 1448 * 1) We have added an unusual amount of run time from fork_exit. 1449 * 2) We have added an unusual amount of sleep time from sched_sleep(). 1450 */ 1451 if (sum > SCHED_SLP_RUN_MAX * 2) { 1452 if (ts->ts_runtime > ts->ts_slptime) { 1453 ts->ts_runtime = SCHED_SLP_RUN_MAX; 1454 ts->ts_slptime = 1; 1455 } else { 1456 ts->ts_slptime = SCHED_SLP_RUN_MAX; 1457 ts->ts_runtime = 1; 1458 } 1459 return; 1460 } 1461 /* 1462 * If we have exceeded by more than 1/5th then the algorithm below 1463 * will not bring us back into range. Dividing by two here forces 1464 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] 1465 */ 1466 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { 1467 ts->ts_runtime /= 2; 1468 ts->ts_slptime /= 2; 1469 return; 1470 } 1471 ts->ts_runtime = (ts->ts_runtime / 5) * 4; 1472 ts->ts_slptime = (ts->ts_slptime / 5) * 4; 1473 } 1474 1475 /* 1476 * Scale back the interactivity history when a child thread is created. The 1477 * history is inherited from the parent but the thread may behave totally 1478 * differently. For example, a shell spawning a compiler process. We want 1479 * to learn that the compiler is behaving badly very quickly. 1480 */ 1481 static void 1482 sched_interact_fork(struct thread *td) 1483 { 1484 int ratio; 1485 int sum; 1486 1487 sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime; 1488 if (sum > SCHED_SLP_RUN_FORK) { 1489 ratio = sum / SCHED_SLP_RUN_FORK; 1490 td->td_sched->ts_runtime /= ratio; 1491 td->td_sched->ts_slptime /= ratio; 1492 } 1493 } 1494 1495 /* 1496 * Called from proc0_init() to setup the scheduler fields. 1497 */ 1498 void 1499 schedinit(void) 1500 { 1501 1502 /* 1503 * Set up the scheduler specific parts of proc0. 1504 */ 1505 proc0.p_sched = NULL; /* XXX */ 1506 thread0.td_sched = &td_sched0; 1507 td_sched0.ts_ltick = ticks; 1508 td_sched0.ts_ftick = ticks; 1509 td_sched0.ts_thread = &thread0; 1510 } 1511 1512 /* 1513 * This is only somewhat accurate since given many processes of the same 1514 * priority they will switch when their slices run out, which will be 1515 * at most sched_slice stathz ticks. 1516 */ 1517 int 1518 sched_rr_interval(void) 1519 { 1520 1521 /* Convert sched_slice to hz */ 1522 return (hz/(realstathz/sched_slice)); 1523 } 1524 1525 /* 1526 * Update the percent cpu tracking information when it is requested or 1527 * the total history exceeds the maximum. We keep a sliding history of 1528 * tick counts that slowly decays. This is less precise than the 4BSD 1529 * mechanism since it happens with less regular and frequent events. 1530 */ 1531 static void 1532 sched_pctcpu_update(struct td_sched *ts) 1533 { 1534 1535 if (ts->ts_ticks == 0) 1536 return; 1537 if (ticks - (hz / 10) < ts->ts_ltick && 1538 SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX) 1539 return; 1540 /* 1541 * Adjust counters and watermark for pctcpu calc. 1542 */ 1543 if (ts->ts_ltick > ticks - SCHED_TICK_TARG) 1544 ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) * 1545 SCHED_TICK_TARG; 1546 else 1547 ts->ts_ticks = 0; 1548 ts->ts_ltick = ticks; 1549 ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG; 1550 } 1551 1552 /* 1553 * Adjust the priority of a thread. Move it to the appropriate run-queue 1554 * if necessary. This is the back-end for several priority related 1555 * functions. 1556 */ 1557 static void 1558 sched_thread_priority(struct thread *td, u_char prio) 1559 { 1560 struct td_sched *ts; 1561 1562 CTR6(KTR_SCHED, "sched_prio: %p(%s) prio %d newprio %d by %p(%s)", 1563 td, td->td_proc->p_comm, td->td_priority, prio, curthread, 1564 curthread->td_proc->p_comm); 1565 ts = td->td_sched; 1566 THREAD_LOCK_ASSERT(td, MA_OWNED); 1567 if (td->td_priority == prio) 1568 return; 1569 1570 if (TD_ON_RUNQ(td) && prio < td->td_priority) { 1571 /* 1572 * If the priority has been elevated due to priority 1573 * propagation, we may have to move ourselves to a new 1574 * queue. This could be optimized to not re-add in some 1575 * cases. 1576 */ 1577 sched_rem(td); 1578 td->td_priority = prio; 1579 sched_add(td, SRQ_BORROWING); 1580 } else { 1581 #ifdef SMP 1582 struct tdq *tdq; 1583 1584 tdq = TDQ_CPU(ts->ts_cpu); 1585 if (prio < tdq->tdq_lowpri) 1586 tdq->tdq_lowpri = prio; 1587 #endif 1588 td->td_priority = prio; 1589 } 1590 } 1591 1592 /* 1593 * Update a thread's priority when it is lent another thread's 1594 * priority. 1595 */ 1596 void 1597 sched_lend_prio(struct thread *td, u_char prio) 1598 { 1599 1600 td->td_flags |= TDF_BORROWING; 1601 sched_thread_priority(td, prio); 1602 } 1603 1604 /* 1605 * Restore a thread's priority when priority propagation is 1606 * over. The prio argument is the minimum priority the thread 1607 * needs to have to satisfy other possible priority lending 1608 * requests. If the thread's regular priority is less 1609 * important than prio, the thread will keep a priority boost 1610 * of prio. 1611 */ 1612 void 1613 sched_unlend_prio(struct thread *td, u_char prio) 1614 { 1615 u_char base_pri; 1616 1617 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 1618 td->td_base_pri <= PRI_MAX_TIMESHARE) 1619 base_pri = td->td_user_pri; 1620 else 1621 base_pri = td->td_base_pri; 1622 if (prio >= base_pri) { 1623 td->td_flags &= ~TDF_BORROWING; 1624 sched_thread_priority(td, base_pri); 1625 } else 1626 sched_lend_prio(td, prio); 1627 } 1628 1629 /* 1630 * Standard entry for setting the priority to an absolute value. 1631 */ 1632 void 1633 sched_prio(struct thread *td, u_char prio) 1634 { 1635 u_char oldprio; 1636 1637 /* First, update the base priority. */ 1638 td->td_base_pri = prio; 1639 1640 /* 1641 * If the thread is borrowing another thread's priority, don't 1642 * ever lower the priority. 1643 */ 1644 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 1645 return; 1646 1647 /* Change the real priority. */ 1648 oldprio = td->td_priority; 1649 sched_thread_priority(td, prio); 1650 1651 /* 1652 * If the thread is on a turnstile, then let the turnstile update 1653 * its state. 1654 */ 1655 if (TD_ON_LOCK(td) && oldprio != prio) 1656 turnstile_adjust(td, oldprio); 1657 } 1658 1659 /* 1660 * Set the base user priority, does not effect current running priority. 1661 */ 1662 void 1663 sched_user_prio(struct thread *td, u_char prio) 1664 { 1665 u_char oldprio; 1666 1667 td->td_base_user_pri = prio; 1668 if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio) 1669 return; 1670 oldprio = td->td_user_pri; 1671 td->td_user_pri = prio; 1672 1673 if (TD_ON_UPILOCK(td) && oldprio != prio) 1674 umtx_pi_adjust(td, oldprio); 1675 } 1676 1677 void 1678 sched_lend_user_prio(struct thread *td, u_char prio) 1679 { 1680 u_char oldprio; 1681 1682 td->td_flags |= TDF_UBORROWING; 1683 1684 oldprio = td->td_user_pri; 1685 td->td_user_pri = prio; 1686 1687 if (TD_ON_UPILOCK(td) && oldprio != prio) 1688 umtx_pi_adjust(td, oldprio); 1689 } 1690 1691 void 1692 sched_unlend_user_prio(struct thread *td, u_char prio) 1693 { 1694 u_char base_pri; 1695 1696 base_pri = td->td_base_user_pri; 1697 if (prio >= base_pri) { 1698 td->td_flags &= ~TDF_UBORROWING; 1699 sched_user_prio(td, base_pri); 1700 } else 1701 sched_lend_user_prio(td, prio); 1702 } 1703 1704 /* 1705 * Add the thread passed as 'newtd' to the run queue before selecting 1706 * the next thread to run. This is only used for KSE. 1707 */ 1708 static void 1709 sched_switchin(struct tdq *tdq, struct thread *td) 1710 { 1711 #ifdef SMP 1712 spinlock_enter(); 1713 TDQ_UNLOCK(tdq); 1714 thread_lock(td); 1715 spinlock_exit(); 1716 sched_setcpu(td->td_sched, TDQ_ID(tdq), SRQ_YIELDING); 1717 #else 1718 td->td_lock = TDQ_LOCKPTR(tdq); 1719 #endif 1720 tdq_add(tdq, td, SRQ_YIELDING); 1721 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1722 } 1723 1724 /* 1725 * Handle migration from sched_switch(). This happens only for 1726 * cpu binding. 1727 */ 1728 static struct mtx * 1729 sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) 1730 { 1731 struct tdq *tdn; 1732 1733 tdn = TDQ_CPU(td->td_sched->ts_cpu); 1734 #ifdef SMP 1735 /* 1736 * Do the lock dance required to avoid LOR. We grab an extra 1737 * spinlock nesting to prevent preemption while we're 1738 * not holding either run-queue lock. 1739 */ 1740 spinlock_enter(); 1741 thread_block_switch(td); /* This releases the lock on tdq. */ 1742 TDQ_LOCK(tdn); 1743 tdq_add(tdn, td, flags); 1744 tdq_notify(td->td_sched); 1745 /* 1746 * After we unlock tdn the new cpu still can't switch into this 1747 * thread until we've unblocked it in cpu_switch(). The lock 1748 * pointers may match in the case of HTT cores. Don't unlock here 1749 * or we can deadlock when the other CPU runs the IPI handler. 1750 */ 1751 if (TDQ_LOCKPTR(tdn) != TDQ_LOCKPTR(tdq)) { 1752 TDQ_UNLOCK(tdn); 1753 TDQ_LOCK(tdq); 1754 } 1755 spinlock_exit(); 1756 #endif 1757 return (TDQ_LOCKPTR(tdn)); 1758 } 1759 1760 /* 1761 * Block a thread for switching. Similar to thread_block() but does not 1762 * bump the spin count. 1763 */ 1764 static inline struct mtx * 1765 thread_block_switch(struct thread *td) 1766 { 1767 struct mtx *lock; 1768 1769 THREAD_LOCK_ASSERT(td, MA_OWNED); 1770 lock = td->td_lock; 1771 td->td_lock = &blocked_lock; 1772 mtx_unlock_spin(lock); 1773 1774 return (lock); 1775 } 1776 1777 /* 1778 * Release a thread that was blocked with thread_block_switch(). 1779 */ 1780 static inline void 1781 thread_unblock_switch(struct thread *td, struct mtx *mtx) 1782 { 1783 atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock, 1784 (uintptr_t)mtx); 1785 } 1786 1787 /* 1788 * Switch threads. This function has to handle threads coming in while 1789 * blocked for some reason, running, or idle. It also must deal with 1790 * migrating a thread from one queue to another as running threads may 1791 * be assigned elsewhere via binding. 1792 */ 1793 void 1794 sched_switch(struct thread *td, struct thread *newtd, int flags) 1795 { 1796 struct tdq *tdq; 1797 struct td_sched *ts; 1798 struct mtx *mtx; 1799 int srqflag; 1800 int cpuid; 1801 1802 THREAD_LOCK_ASSERT(td, MA_OWNED); 1803 1804 cpuid = PCPU_GET(cpuid); 1805 tdq = TDQ_CPU(cpuid); 1806 ts = td->td_sched; 1807 mtx = td->td_lock; 1808 #ifdef SMP 1809 ts->ts_rltick = ticks; 1810 if (newtd && newtd->td_priority < tdq->tdq_lowpri) 1811 tdq->tdq_lowpri = newtd->td_priority; 1812 #endif 1813 td->td_lastcpu = td->td_oncpu; 1814 td->td_oncpu = NOCPU; 1815 td->td_flags &= ~TDF_NEEDRESCHED; 1816 td->td_owepreempt = 0; 1817 /* 1818 * The lock pointer in an idle thread should never change. Reset it 1819 * to CAN_RUN as well. 1820 */ 1821 if (TD_IS_IDLETHREAD(td)) { 1822 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1823 TD_SET_CAN_RUN(td); 1824 } else if (TD_IS_RUNNING(td)) { 1825 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1826 tdq_load_rem(tdq, ts); 1827 srqflag = (flags & SW_PREEMPT) ? 1828 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1829 SRQ_OURSELF|SRQ_YIELDING; 1830 if (ts->ts_cpu == cpuid) 1831 tdq_add(tdq, td, srqflag); 1832 else 1833 mtx = sched_switch_migrate(tdq, td, srqflag); 1834 } else { 1835 /* This thread must be going to sleep. */ 1836 TDQ_LOCK(tdq); 1837 mtx = thread_block_switch(td); 1838 tdq_load_rem(tdq, ts); 1839 } 1840 /* 1841 * We enter here with the thread blocked and assigned to the 1842 * appropriate cpu run-queue or sleep-queue and with the current 1843 * thread-queue locked. 1844 */ 1845 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 1846 /* 1847 * If KSE assigned a new thread just add it here and let choosethread 1848 * select the best one. 1849 */ 1850 if (newtd != NULL) 1851 sched_switchin(tdq, newtd); 1852 newtd = choosethread(); 1853 /* 1854 * Call the MD code to switch contexts if necessary. 1855 */ 1856 if (td != newtd) { 1857 #ifdef HWPMC_HOOKS 1858 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1859 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1860 #endif 1861 cpu_switch(td, newtd, mtx); 1862 /* 1863 * We may return from cpu_switch on a different cpu. However, 1864 * we always return with td_lock pointing to the current cpu's 1865 * run queue lock. 1866 */ 1867 cpuid = PCPU_GET(cpuid); 1868 tdq = TDQ_CPU(cpuid); 1869 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)td; 1870 #ifdef HWPMC_HOOKS 1871 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1872 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1873 #endif 1874 } else 1875 thread_unblock_switch(td, mtx); 1876 /* 1877 * Assert that all went well and return. 1878 */ 1879 #ifdef SMP 1880 /* We should always get here with the lowest priority td possible */ 1881 tdq->tdq_lowpri = td->td_priority; 1882 #endif 1883 TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED); 1884 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1885 td->td_oncpu = cpuid; 1886 } 1887 1888 /* 1889 * Adjust thread priorities as a result of a nice request. 1890 */ 1891 void 1892 sched_nice(struct proc *p, int nice) 1893 { 1894 struct thread *td; 1895 1896 PROC_LOCK_ASSERT(p, MA_OWNED); 1897 PROC_SLOCK_ASSERT(p, MA_OWNED); 1898 1899 p->p_nice = nice; 1900 FOREACH_THREAD_IN_PROC(p, td) { 1901 thread_lock(td); 1902 sched_priority(td); 1903 sched_prio(td, td->td_base_user_pri); 1904 thread_unlock(td); 1905 } 1906 } 1907 1908 /* 1909 * Record the sleep time for the interactivity scorer. 1910 */ 1911 void 1912 sched_sleep(struct thread *td) 1913 { 1914 1915 THREAD_LOCK_ASSERT(td, MA_OWNED); 1916 1917 td->td_sched->ts_slptick = ticks; 1918 } 1919 1920 /* 1921 * Schedule a thread to resume execution and record how long it voluntarily 1922 * slept. We also update the pctcpu, interactivity, and priority. 1923 */ 1924 void 1925 sched_wakeup(struct thread *td) 1926 { 1927 struct td_sched *ts; 1928 int slptick; 1929 1930 THREAD_LOCK_ASSERT(td, MA_OWNED); 1931 ts = td->td_sched; 1932 /* 1933 * If we slept for more than a tick update our interactivity and 1934 * priority. 1935 */ 1936 slptick = ts->ts_slptick; 1937 ts->ts_slptick = 0; 1938 if (slptick && slptick != ticks) { 1939 u_int hzticks; 1940 1941 hzticks = (ticks - slptick) << SCHED_TICK_SHIFT; 1942 ts->ts_slptime += hzticks; 1943 sched_interact_update(td); 1944 sched_pctcpu_update(ts); 1945 sched_priority(td); 1946 } 1947 /* Reset the slice value after we sleep. */ 1948 ts->ts_slice = sched_slice; 1949 sched_add(td, SRQ_BORING); 1950 } 1951 1952 /* 1953 * Penalize the parent for creating a new child and initialize the child's 1954 * priority. 1955 */ 1956 void 1957 sched_fork(struct thread *td, struct thread *child) 1958 { 1959 THREAD_LOCK_ASSERT(td, MA_OWNED); 1960 sched_fork_thread(td, child); 1961 /* 1962 * Penalize the parent and child for forking. 1963 */ 1964 sched_interact_fork(child); 1965 sched_priority(child); 1966 td->td_sched->ts_runtime += tickincr; 1967 sched_interact_update(td); 1968 sched_priority(td); 1969 } 1970 1971 /* 1972 * Fork a new thread, may be within the same process. 1973 */ 1974 void 1975 sched_fork_thread(struct thread *td, struct thread *child) 1976 { 1977 struct td_sched *ts; 1978 struct td_sched *ts2; 1979 1980 /* 1981 * Initialize child. 1982 */ 1983 THREAD_LOCK_ASSERT(td, MA_OWNED); 1984 sched_newthread(child); 1985 child->td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1986 ts = td->td_sched; 1987 ts2 = child->td_sched; 1988 ts2->ts_cpu = ts->ts_cpu; 1989 ts2->ts_runq = NULL; 1990 /* 1991 * Grab our parents cpu estimation information and priority. 1992 */ 1993 ts2->ts_ticks = ts->ts_ticks; 1994 ts2->ts_ltick = ts->ts_ltick; 1995 ts2->ts_ftick = ts->ts_ftick; 1996 child->td_user_pri = td->td_user_pri; 1997 child->td_base_user_pri = td->td_base_user_pri; 1998 /* 1999 * And update interactivity score. 2000 */ 2001 ts2->ts_slptime = ts->ts_slptime; 2002 ts2->ts_runtime = ts->ts_runtime; 2003 ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */ 2004 } 2005 2006 /* 2007 * Adjust the priority class of a thread. 2008 */ 2009 void 2010 sched_class(struct thread *td, int class) 2011 { 2012 2013 THREAD_LOCK_ASSERT(td, MA_OWNED); 2014 if (td->td_pri_class == class) 2015 return; 2016 2017 #ifdef SMP 2018 /* 2019 * On SMP if we're on the RUNQ we must adjust the transferable 2020 * count because could be changing to or from an interrupt 2021 * class. 2022 */ 2023 if (TD_ON_RUNQ(td)) { 2024 struct tdq *tdq; 2025 2026 tdq = TDQ_CPU(td->td_sched->ts_cpu); 2027 if (THREAD_CAN_MIGRATE(td)) { 2028 tdq->tdq_transferable--; 2029 tdq->tdq_group->tdg_transferable--; 2030 } 2031 td->td_pri_class = class; 2032 if (THREAD_CAN_MIGRATE(td)) { 2033 tdq->tdq_transferable++; 2034 tdq->tdq_group->tdg_transferable++; 2035 } 2036 } 2037 #endif 2038 td->td_pri_class = class; 2039 } 2040 2041 /* 2042 * Return some of the child's priority and interactivity to the parent. 2043 */ 2044 void 2045 sched_exit(struct proc *p, struct thread *child) 2046 { 2047 struct thread *td; 2048 2049 CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d", 2050 child, child->td_proc->p_comm, child->td_priority); 2051 2052 PROC_SLOCK_ASSERT(p, MA_OWNED); 2053 td = FIRST_THREAD_IN_PROC(p); 2054 sched_exit_thread(td, child); 2055 } 2056 2057 /* 2058 * Penalize another thread for the time spent on this one. This helps to 2059 * worsen the priority and interactivity of processes which schedule batch 2060 * jobs such as make. This has little effect on the make process itself but 2061 * causes new processes spawned by it to receive worse scores immediately. 2062 */ 2063 void 2064 sched_exit_thread(struct thread *td, struct thread *child) 2065 { 2066 2067 CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d", 2068 child, child->td_proc->p_comm, child->td_priority); 2069 2070 #ifdef KSE 2071 /* 2072 * KSE forks and exits so often that this penalty causes short-lived 2073 * threads to always be non-interactive. This causes mozilla to 2074 * crawl under load. 2075 */ 2076 if ((td->td_pflags & TDP_SA) && td->td_proc == child->td_proc) 2077 return; 2078 #endif 2079 /* 2080 * Give the child's runtime to the parent without returning the 2081 * sleep time as a penalty to the parent. This causes shells that 2082 * launch expensive things to mark their children as expensive. 2083 */ 2084 thread_lock(td); 2085 td->td_sched->ts_runtime += child->td_sched->ts_runtime; 2086 sched_interact_update(td); 2087 sched_priority(td); 2088 thread_unlock(td); 2089 } 2090 2091 /* 2092 * Fix priorities on return to user-space. Priorities may be elevated due 2093 * to static priorities in msleep() or similar. 2094 */ 2095 void 2096 sched_userret(struct thread *td) 2097 { 2098 /* 2099 * XXX we cheat slightly on the locking here to avoid locking in 2100 * the usual case. Setting td_priority here is essentially an 2101 * incomplete workaround for not setting it properly elsewhere. 2102 * Now that some interrupt handlers are threads, not setting it 2103 * properly elsewhere can clobber it in the window between setting 2104 * it here and returning to user mode, so don't waste time setting 2105 * it perfectly here. 2106 */ 2107 KASSERT((td->td_flags & TDF_BORROWING) == 0, 2108 ("thread with borrowed priority returning to userland")); 2109 if (td->td_priority != td->td_user_pri) { 2110 thread_lock(td); 2111 td->td_priority = td->td_user_pri; 2112 td->td_base_pri = td->td_user_pri; 2113 thread_unlock(td); 2114 } 2115 } 2116 2117 /* 2118 * Handle a stathz tick. This is really only relevant for timeshare 2119 * threads. 2120 */ 2121 void 2122 sched_clock(struct thread *td) 2123 { 2124 struct tdq *tdq; 2125 struct td_sched *ts; 2126 2127 THREAD_LOCK_ASSERT(td, MA_OWNED); 2128 tdq = TDQ_SELF(); 2129 /* 2130 * Advance the insert index once for each tick to ensure that all 2131 * threads get a chance to run. 2132 */ 2133 if (tdq->tdq_idx == tdq->tdq_ridx) { 2134 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; 2135 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) 2136 tdq->tdq_ridx = tdq->tdq_idx; 2137 } 2138 ts = td->td_sched; 2139 /* 2140 * We only do slicing code for TIMESHARE threads. 2141 */ 2142 if (td->td_pri_class != PRI_TIMESHARE) 2143 return; 2144 /* 2145 * We used a tick; charge it to the thread so that we can compute our 2146 * interactivity. 2147 */ 2148 td->td_sched->ts_runtime += tickincr; 2149 sched_interact_update(td); 2150 /* 2151 * We used up one time slice. 2152 */ 2153 if (--ts->ts_slice > 0) 2154 return; 2155 /* 2156 * We're out of time, recompute priorities and requeue. 2157 */ 2158 sched_priority(td); 2159 td->td_flags |= TDF_NEEDRESCHED; 2160 } 2161 2162 /* 2163 * Called once per hz tick. Used for cpu utilization information. This 2164 * is easier than trying to scale based on stathz. 2165 */ 2166 void 2167 sched_tick(void) 2168 { 2169 struct td_sched *ts; 2170 2171 ts = curthread->td_sched; 2172 /* Adjust ticks for pctcpu */ 2173 ts->ts_ticks += 1 << SCHED_TICK_SHIFT; 2174 ts->ts_ltick = ticks; 2175 /* 2176 * Update if we've exceeded our desired tick threshhold by over one 2177 * second. 2178 */ 2179 if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick) 2180 sched_pctcpu_update(ts); 2181 } 2182 2183 /* 2184 * Return whether the current CPU has runnable tasks. Used for in-kernel 2185 * cooperative idle threads. 2186 */ 2187 int 2188 sched_runnable(void) 2189 { 2190 struct tdq *tdq; 2191 int load; 2192 2193 load = 1; 2194 2195 tdq = TDQ_SELF(); 2196 if ((curthread->td_flags & TDF_IDLETD) != 0) { 2197 if (tdq->tdq_load > 0) 2198 goto out; 2199 } else 2200 if (tdq->tdq_load - 1 > 0) 2201 goto out; 2202 load = 0; 2203 out: 2204 return (load); 2205 } 2206 2207 /* 2208 * Choose the highest priority thread to run. The thread is removed from 2209 * the run-queue while running however the load remains. For SMP we set 2210 * the tdq in the global idle bitmask if it idles here. 2211 */ 2212 struct thread * 2213 sched_choose(void) 2214 { 2215 #ifdef SMP 2216 struct tdq_group *tdg; 2217 #endif 2218 struct td_sched *ts; 2219 struct tdq *tdq; 2220 2221 tdq = TDQ_SELF(); 2222 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2223 ts = tdq_choose(tdq); 2224 if (ts) { 2225 tdq_runq_rem(tdq, ts); 2226 return (ts->ts_thread); 2227 } 2228 #ifdef SMP 2229 /* 2230 * We only set the idled bit when all of the cpus in the group are 2231 * idle. Otherwise we could get into a situation where a thread bounces 2232 * back and forth between two idle cores on seperate physical CPUs. 2233 */ 2234 tdg = tdq->tdq_group; 2235 tdg->tdg_idlemask |= PCPU_GET(cpumask); 2236 if (tdg->tdg_idlemask == tdg->tdg_cpumask) 2237 atomic_set_int(&tdq_idle, tdg->tdg_mask); 2238 tdq->tdq_lowpri = PRI_MAX_IDLE; 2239 #endif 2240 return (PCPU_GET(idlethread)); 2241 } 2242 2243 /* 2244 * Set owepreempt if necessary. Preemption never happens directly in ULE, 2245 * we always request it once we exit a critical section. 2246 */ 2247 static inline void 2248 sched_setpreempt(struct thread *td) 2249 { 2250 struct thread *ctd; 2251 int cpri; 2252 int pri; 2253 2254 ctd = curthread; 2255 pri = td->td_priority; 2256 cpri = ctd->td_priority; 2257 if (td->td_priority < ctd->td_priority) 2258 curthread->td_flags |= TDF_NEEDRESCHED; 2259 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) 2260 return; 2261 /* 2262 * Always preempt IDLE threads. Otherwise only if the preempting 2263 * thread is an ithread. 2264 */ 2265 if (pri > preempt_thresh && cpri < PRI_MIN_IDLE) 2266 return; 2267 ctd->td_owepreempt = 1; 2268 return; 2269 } 2270 2271 /* 2272 * Add a thread to a thread queue. Initializes priority, slice, runq, and 2273 * add it to the appropriate queue. This is the internal function called 2274 * when the tdq is predetermined. 2275 */ 2276 void 2277 tdq_add(struct tdq *tdq, struct thread *td, int flags) 2278 { 2279 struct td_sched *ts; 2280 int class; 2281 #ifdef SMP 2282 int cpumask; 2283 #endif 2284 2285 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2286 KASSERT((td->td_inhibitors == 0), 2287 ("sched_add: trying to run inhibited thread")); 2288 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 2289 ("sched_add: bad thread state")); 2290 KASSERT(td->td_proc->p_sflag & PS_INMEM, 2291 ("sched_add: process swapped out")); 2292 2293 ts = td->td_sched; 2294 class = PRI_BASE(td->td_pri_class); 2295 TD_SET_RUNQ(td); 2296 if (ts->ts_slice == 0) 2297 ts->ts_slice = sched_slice; 2298 /* 2299 * Pick the run queue based on priority. 2300 */ 2301 if (td->td_priority <= PRI_MAX_REALTIME) 2302 ts->ts_runq = &tdq->tdq_realtime; 2303 else if (td->td_priority <= PRI_MAX_TIMESHARE) 2304 ts->ts_runq = &tdq->tdq_timeshare; 2305 else 2306 ts->ts_runq = &tdq->tdq_idle; 2307 #ifdef SMP 2308 cpumask = 1 << ts->ts_cpu; 2309 /* 2310 * If we had been idle, clear our bit in the group and potentially 2311 * the global bitmap. 2312 */ 2313 if ((class != PRI_IDLE && class != PRI_ITHD) && 2314 (tdq->tdq_group->tdg_idlemask & cpumask) != 0) { 2315 /* 2316 * Check to see if our group is unidling, and if so, remove it 2317 * from the global idle mask. 2318 */ 2319 if (tdq->tdq_group->tdg_idlemask == 2320 tdq->tdq_group->tdg_cpumask) 2321 atomic_clear_int(&tdq_idle, tdq->tdq_group->tdg_mask); 2322 /* 2323 * Now remove ourselves from the group specific idle mask. 2324 */ 2325 tdq->tdq_group->tdg_idlemask &= ~cpumask; 2326 } 2327 if (td->td_priority < tdq->tdq_lowpri) 2328 tdq->tdq_lowpri = td->td_priority; 2329 #endif 2330 tdq_runq_add(tdq, ts, flags); 2331 tdq_load_add(tdq, ts); 2332 } 2333 2334 /* 2335 * Select the target thread queue and add a thread to it. Request 2336 * preemption or IPI a remote processor if required. 2337 */ 2338 void 2339 sched_add(struct thread *td, int flags) 2340 { 2341 struct td_sched *ts; 2342 struct tdq *tdq; 2343 #ifdef SMP 2344 int cpuid; 2345 int cpu; 2346 #endif 2347 CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)", 2348 td, td->td_proc->p_comm, td->td_priority, curthread, 2349 curthread->td_proc->p_comm); 2350 THREAD_LOCK_ASSERT(td, MA_OWNED); 2351 ts = td->td_sched; 2352 /* 2353 * Recalculate the priority before we select the target cpu or 2354 * run-queue. 2355 */ 2356 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 2357 sched_priority(td); 2358 #ifdef SMP 2359 cpuid = PCPU_GET(cpuid); 2360 /* 2361 * Pick the destination cpu and if it isn't ours transfer to the 2362 * target cpu. 2363 */ 2364 if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_MIGRATE(td)) 2365 cpu = cpuid; 2366 else if (!THREAD_CAN_MIGRATE(td)) 2367 cpu = ts->ts_cpu; 2368 else 2369 cpu = sched_pickcpu(ts, flags); 2370 tdq = sched_setcpu(ts, cpu, flags); 2371 tdq_add(tdq, td, flags); 2372 if (cpu != cpuid) { 2373 tdq_notify(ts); 2374 return; 2375 } 2376 #else 2377 tdq = TDQ_SELF(); 2378 TDQ_LOCK(tdq); 2379 /* 2380 * Now that the thread is moving to the run-queue, set the lock 2381 * to the scheduler's lock. 2382 */ 2383 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 2384 tdq_add(tdq, td, flags); 2385 #endif 2386 if (!(flags & SRQ_YIELDING)) 2387 sched_setpreempt(td); 2388 } 2389 2390 /* 2391 * Remove a thread from a run-queue without running it. This is used 2392 * when we're stealing a thread from a remote queue. Otherwise all threads 2393 * exit by calling sched_exit_thread() and sched_throw() themselves. 2394 */ 2395 void 2396 sched_rem(struct thread *td) 2397 { 2398 struct tdq *tdq; 2399 struct td_sched *ts; 2400 2401 CTR5(KTR_SCHED, "sched_rem: %p(%s) prio %d by %p(%s)", 2402 td, td->td_proc->p_comm, td->td_priority, curthread, 2403 curthread->td_proc->p_comm); 2404 ts = td->td_sched; 2405 tdq = TDQ_CPU(ts->ts_cpu); 2406 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2407 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2408 KASSERT(TD_ON_RUNQ(td), 2409 ("sched_rem: thread not on run queue")); 2410 tdq_runq_rem(tdq, ts); 2411 tdq_load_rem(tdq, ts); 2412 TD_SET_CAN_RUN(td); 2413 } 2414 2415 /* 2416 * Fetch cpu utilization information. Updates on demand. 2417 */ 2418 fixpt_t 2419 sched_pctcpu(struct thread *td) 2420 { 2421 fixpt_t pctcpu; 2422 struct td_sched *ts; 2423 2424 pctcpu = 0; 2425 ts = td->td_sched; 2426 if (ts == NULL) 2427 return (0); 2428 2429 thread_lock(td); 2430 if (ts->ts_ticks) { 2431 int rtick; 2432 2433 sched_pctcpu_update(ts); 2434 /* How many rtick per second ? */ 2435 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); 2436 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; 2437 } 2438 td->td_proc->p_swtime = ts->ts_ltick - ts->ts_ftick; 2439 thread_unlock(td); 2440 2441 return (pctcpu); 2442 } 2443 2444 /* 2445 * Bind a thread to a target cpu. 2446 */ 2447 void 2448 sched_bind(struct thread *td, int cpu) 2449 { 2450 struct td_sched *ts; 2451 2452 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 2453 ts = td->td_sched; 2454 if (ts->ts_flags & TSF_BOUND) 2455 sched_unbind(td); 2456 ts->ts_flags |= TSF_BOUND; 2457 #ifdef SMP 2458 sched_pin(); 2459 if (PCPU_GET(cpuid) == cpu) 2460 return; 2461 ts->ts_cpu = cpu; 2462 /* When we return from mi_switch we'll be on the correct cpu. */ 2463 mi_switch(SW_VOL, NULL); 2464 #endif 2465 } 2466 2467 /* 2468 * Release a bound thread. 2469 */ 2470 void 2471 sched_unbind(struct thread *td) 2472 { 2473 struct td_sched *ts; 2474 2475 THREAD_LOCK_ASSERT(td, MA_OWNED); 2476 ts = td->td_sched; 2477 if ((ts->ts_flags & TSF_BOUND) == 0) 2478 return; 2479 ts->ts_flags &= ~TSF_BOUND; 2480 #ifdef SMP 2481 sched_unpin(); 2482 #endif 2483 } 2484 2485 int 2486 sched_is_bound(struct thread *td) 2487 { 2488 THREAD_LOCK_ASSERT(td, MA_OWNED); 2489 return (td->td_sched->ts_flags & TSF_BOUND); 2490 } 2491 2492 /* 2493 * Basic yield call. 2494 */ 2495 void 2496 sched_relinquish(struct thread *td) 2497 { 2498 thread_lock(td); 2499 if (td->td_pri_class == PRI_TIMESHARE) 2500 sched_prio(td, PRI_MAX_TIMESHARE); 2501 SCHED_STAT_INC(switch_relinquish); 2502 mi_switch(SW_VOL, NULL); 2503 thread_unlock(td); 2504 } 2505 2506 /* 2507 * Return the total system load. 2508 */ 2509 int 2510 sched_load(void) 2511 { 2512 #ifdef SMP 2513 int total; 2514 int i; 2515 2516 total = 0; 2517 for (i = 0; i <= tdg_maxid; i++) 2518 total += TDQ_GROUP(i)->tdg_load; 2519 return (total); 2520 #else 2521 return (TDQ_SELF()->tdq_sysload); 2522 #endif 2523 } 2524 2525 int 2526 sched_sizeof_proc(void) 2527 { 2528 return (sizeof(struct proc)); 2529 } 2530 2531 int 2532 sched_sizeof_thread(void) 2533 { 2534 return (sizeof(struct thread) + sizeof(struct td_sched)); 2535 } 2536 2537 /* 2538 * The actual idle process. 2539 */ 2540 void 2541 sched_idletd(void *dummy) 2542 { 2543 struct thread *td; 2544 struct tdq *tdq; 2545 2546 td = curthread; 2547 tdq = TDQ_SELF(); 2548 mtx_assert(&Giant, MA_NOTOWNED); 2549 /* ULE relies on preemption for idle interruption. */ 2550 for (;;) { 2551 #ifdef SMP 2552 if (tdq_idled(tdq)) 2553 cpu_idle(); 2554 #else 2555 cpu_idle(); 2556 #endif 2557 } 2558 } 2559 2560 /* 2561 * A CPU is entering for the first time or a thread is exiting. 2562 */ 2563 void 2564 sched_throw(struct thread *td) 2565 { 2566 struct tdq *tdq; 2567 2568 tdq = TDQ_SELF(); 2569 if (td == NULL) { 2570 /* Correct spinlock nesting and acquire the correct lock. */ 2571 TDQ_LOCK(tdq); 2572 spinlock_exit(); 2573 } else { 2574 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2575 tdq_load_rem(tdq, td->td_sched); 2576 } 2577 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 2578 PCPU_SET(switchtime, cpu_ticks()); 2579 PCPU_SET(switchticks, ticks); 2580 cpu_throw(td, choosethread()); /* doesn't return */ 2581 } 2582 2583 /* 2584 * This is called from fork_exit(). Just acquire the correct locks and 2585 * let fork do the rest of the work. 2586 */ 2587 void 2588 sched_fork_exit(struct thread *td) 2589 { 2590 struct td_sched *ts; 2591 struct tdq *tdq; 2592 int cpuid; 2593 2594 /* 2595 * Finish setting up thread glue so that it begins execution in a 2596 * non-nested critical section with the scheduler lock held. 2597 */ 2598 cpuid = PCPU_GET(cpuid); 2599 tdq = TDQ_CPU(cpuid); 2600 ts = td->td_sched; 2601 if (TD_IS_IDLETHREAD(td)) 2602 td->td_lock = TDQ_LOCKPTR(tdq); 2603 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2604 td->td_oncpu = cpuid; 2605 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)td; 2606 THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED); 2607 } 2608 2609 static SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, 2610 "Scheduler"); 2611 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0, 2612 "Scheduler name"); 2613 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 2614 "Slice size for timeshare threads"); 2615 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, 2616 "Interactivity score threshold"); 2617 SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh, 2618 0,"Min priority for preemption, lower priorities have greater precedence"); 2619 #ifdef SMP 2620 SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri, CTLFLAG_RW, &pick_pri, 0, 2621 "Pick the target cpu based on priority rather than load."); 2622 SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0, 2623 "Number of hz ticks to keep thread affinity for"); 2624 SYSCTL_INT(_kern_sched, OID_AUTO, tryself, CTLFLAG_RW, &tryself, 0, ""); 2625 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, 2626 "Enables the long-term load balancer"); 2627 SYSCTL_INT(_kern_sched, OID_AUTO, balance_secs, CTLFLAG_RW, &balance_secs, 0, 2628 "Average frequence in seconds to run the long-term balancer"); 2629 SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0, 2630 "Steals work from another hyper-threaded core on idle"); 2631 SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0, 2632 "Attempts to steal work from other cores before idling"); 2633 SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0, 2634 "Minimum load on remote cpu before we'll steal"); 2635 SYSCTL_INT(_kern_sched, OID_AUTO, topology, CTLFLAG_RD, &topology, 0, 2636 "True when a topology has been specified by the MD code."); 2637 #endif 2638 2639 /* ps compat */ 2640 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 2641 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 2642 2643 2644 #define KERN_SWITCH_INCLUDE 1 2645 #include "kern/kern_switch.c" 2646