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_kdtrace.h" 43 #include "opt_sched.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/kdb.h> 48 #include <sys/kernel.h> 49 #include <sys/ktr.h> 50 #include <sys/lock.h> 51 #include <sys/mutex.h> 52 #include <sys/proc.h> 53 #include <sys/resource.h> 54 #include <sys/resourcevar.h> 55 #include <sys/sched.h> 56 #include <sys/smp.h> 57 #include <sys/sx.h> 58 #include <sys/sysctl.h> 59 #include <sys/sysproto.h> 60 #include <sys/turnstile.h> 61 #include <sys/umtx.h> 62 #include <sys/vmmeter.h> 63 #include <sys/cpuset.h> 64 #include <sys/sbuf.h> 65 #ifdef KTRACE 66 #include <sys/uio.h> 67 #include <sys/ktrace.h> 68 #endif 69 70 #ifdef HWPMC_HOOKS 71 #include <sys/pmckern.h> 72 #endif 73 74 #ifdef KDTRACE_HOOKS 75 #include <sys/dtrace_bsd.h> 76 int dtrace_vtime_active; 77 dtrace_vtime_switch_func_t dtrace_vtime_switch_func; 78 #endif 79 80 #include <machine/cpu.h> 81 #include <machine/smp.h> 82 83 #if defined(__sparc64__) || defined(__mips__) 84 #error "This architecture is not currently compatible with ULE" 85 #endif 86 87 #define KTR_ULE 0 88 89 /* 90 * Thread scheduler specific section. All fields are protected 91 * by the thread lock. 92 */ 93 struct td_sched { 94 struct runq *ts_runq; /* Run-queue we're queued on. */ 95 short ts_flags; /* TSF_* flags. */ 96 u_char ts_cpu; /* CPU that we have affinity for. */ 97 int ts_rltick; /* Real last tick, for affinity. */ 98 int ts_slice; /* Ticks of slice remaining. */ 99 u_int ts_slptime; /* Number of ticks we vol. slept */ 100 u_int ts_runtime; /* Number of ticks we were running */ 101 int ts_ltick; /* Last tick that we were running on */ 102 int ts_ftick; /* First tick that we were running on */ 103 int ts_ticks; /* Tick count */ 104 }; 105 /* flags kept in ts_flags */ 106 #define TSF_BOUND 0x0001 /* Thread can not migrate. */ 107 #define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */ 108 109 static struct td_sched td_sched0; 110 111 #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0) 112 #define THREAD_CAN_SCHED(td, cpu) \ 113 CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask) 114 115 /* 116 * Cpu percentage computation macros and defines. 117 * 118 * SCHED_TICK_SECS: Number of seconds to average the cpu usage across. 119 * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across. 120 * SCHED_TICK_MAX: Maximum number of ticks before scaling back. 121 * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results. 122 * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count. 123 * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks. 124 */ 125 #define SCHED_TICK_SECS 10 126 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS) 127 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz) 128 #define SCHED_TICK_SHIFT 10 129 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT) 130 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz)) 131 132 /* 133 * These macros determine priorities for non-interactive threads. They are 134 * assigned a priority based on their recent cpu utilization as expressed 135 * by the ratio of ticks to the tick total. NHALF priorities at the start 136 * and end of the MIN to MAX timeshare range are only reachable with negative 137 * or positive nice respectively. 138 * 139 * PRI_RANGE: Priority range for utilization dependent priorities. 140 * PRI_NRESV: Number of nice values. 141 * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total. 142 * PRI_NICE: Determines the part of the priority inherited from nice. 143 */ 144 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN) 145 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) 146 #define SCHED_PRI_MIN (PRI_MIN_TIMESHARE + SCHED_PRI_NHALF) 147 #define SCHED_PRI_MAX (PRI_MAX_TIMESHARE - SCHED_PRI_NHALF) 148 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN) 149 #define SCHED_PRI_TICKS(ts) \ 150 (SCHED_TICK_HZ((ts)) / \ 151 (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE)) 152 #define SCHED_PRI_NICE(nice) (nice) 153 154 /* 155 * These determine the interactivity of a process. Interactivity differs from 156 * cpu utilization in that it expresses the voluntary time slept vs time ran 157 * while cpu utilization includes all time not running. This more accurately 158 * models the intent of the thread. 159 * 160 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 161 * before throttling back. 162 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. 163 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 164 * INTERACT_THRESH: Threshhold for placement on the current runq. 165 */ 166 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT) 167 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT) 168 #define SCHED_INTERACT_MAX (100) 169 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 170 #define SCHED_INTERACT_THRESH (30) 171 172 /* 173 * tickincr: Converts a stathz tick into a hz domain scaled by 174 * the shift factor. Without the shift the error rate 175 * due to rounding would be unacceptably high. 176 * realstathz: stathz is sometimes 0 and run off of hz. 177 * sched_slice: Runtime of each thread before rescheduling. 178 * preempt_thresh: Priority threshold for preemption and remote IPIs. 179 */ 180 static int sched_interact = SCHED_INTERACT_THRESH; 181 static int realstathz; 182 static int tickincr; 183 static int sched_slice = 1; 184 #ifdef PREEMPTION 185 #ifdef FULL_PREEMPTION 186 static int preempt_thresh = PRI_MAX_IDLE; 187 #else 188 static int preempt_thresh = PRI_MIN_KERN; 189 #endif 190 #else 191 static int preempt_thresh = 0; 192 #endif 193 static int static_boost = PRI_MIN_TIMESHARE; 194 static int sched_idlespins = 10000; 195 static int sched_idlespinthresh = 4; 196 197 /* 198 * tdq - per processor runqs and statistics. All fields are protected by the 199 * tdq_lock. The load and lowpri may be accessed without to avoid excess 200 * locking in sched_pickcpu(); 201 */ 202 struct tdq { 203 /* Ordered to improve efficiency of cpu_search() and switch(). */ 204 struct mtx tdq_lock; /* run queue lock. */ 205 struct cpu_group *tdq_cg; /* Pointer to cpu topology. */ 206 volatile int tdq_load; /* Aggregate load. */ 207 int tdq_sysload; /* For loadavg, !ITHD load. */ 208 int tdq_transferable; /* Transferable thread count. */ 209 volatile int tdq_idlestate; /* State of the idle thread. */ 210 short tdq_switchcnt; /* Switches this tick. */ 211 short tdq_oldswitchcnt; /* Switches last tick. */ 212 u_char tdq_lowpri; /* Lowest priority thread. */ 213 u_char tdq_ipipending; /* IPI pending. */ 214 u_char tdq_idx; /* Current insert index. */ 215 u_char tdq_ridx; /* Current removal index. */ 216 struct runq tdq_realtime; /* real-time run queue. */ 217 struct runq tdq_timeshare; /* timeshare run queue. */ 218 struct runq tdq_idle; /* Queue of IDLE threads. */ 219 char tdq_name[sizeof("sched lock") + 6]; 220 } __aligned(64); 221 222 /* Idle thread states and config. */ 223 #define TDQ_RUNNING 1 224 #define TDQ_IDLE 2 225 226 #ifdef SMP 227 struct cpu_group *cpu_top; /* CPU topology */ 228 229 #define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000)) 230 #define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity)) 231 232 /* 233 * Run-time tunables. 234 */ 235 static int rebalance = 1; 236 static int balance_interval = 128; /* Default set in sched_initticks(). */ 237 static int affinity; 238 static int steal_htt = 1; 239 static int steal_idle = 1; 240 static int steal_thresh = 2; 241 242 /* 243 * One thread queue per processor. 244 */ 245 static struct tdq tdq_cpu[MAXCPU]; 246 static struct tdq *balance_tdq; 247 static int balance_ticks; 248 249 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)]) 250 #define TDQ_CPU(x) (&tdq_cpu[(x)]) 251 #define TDQ_ID(x) ((int)((x) - tdq_cpu)) 252 #else /* !SMP */ 253 static struct tdq tdq_cpu; 254 255 #define TDQ_ID(x) (0) 256 #define TDQ_SELF() (&tdq_cpu) 257 #define TDQ_CPU(x) (&tdq_cpu) 258 #endif 259 260 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type)) 261 #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t))) 262 #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f)) 263 #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t))) 264 #define TDQ_LOCKPTR(t) (&(t)->tdq_lock) 265 266 static void sched_priority(struct thread *); 267 static void sched_thread_priority(struct thread *, u_char); 268 static int sched_interact_score(struct thread *); 269 static void sched_interact_update(struct thread *); 270 static void sched_interact_fork(struct thread *); 271 static void sched_pctcpu_update(struct td_sched *); 272 273 /* Operations on per processor queues */ 274 static struct thread *tdq_choose(struct tdq *); 275 static void tdq_setup(struct tdq *); 276 static void tdq_load_add(struct tdq *, struct thread *); 277 static void tdq_load_rem(struct tdq *, struct thread *); 278 static __inline void tdq_runq_add(struct tdq *, struct thread *, int); 279 static __inline void tdq_runq_rem(struct tdq *, struct thread *); 280 static inline int sched_shouldpreempt(int, int, int); 281 void tdq_print(int cpu); 282 static void runq_print(struct runq *rq); 283 static void tdq_add(struct tdq *, struct thread *, int); 284 #ifdef SMP 285 static int tdq_move(struct tdq *, struct tdq *); 286 static int tdq_idled(struct tdq *); 287 static void tdq_notify(struct tdq *, struct thread *); 288 static struct thread *tdq_steal(struct tdq *, int); 289 static struct thread *runq_steal(struct runq *, int); 290 static int sched_pickcpu(struct thread *, int); 291 static void sched_balance(void); 292 static int sched_balance_pair(struct tdq *, struct tdq *); 293 static inline struct tdq *sched_setcpu(struct thread *, int, int); 294 static inline struct mtx *thread_block_switch(struct thread *); 295 static inline void thread_unblock_switch(struct thread *, struct mtx *); 296 static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int); 297 static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS); 298 static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, 299 struct cpu_group *cg, int indent); 300 #endif 301 302 static void sched_setup(void *dummy); 303 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL); 304 305 static void sched_initticks(void *dummy); 306 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, 307 NULL); 308 309 /* 310 * Print the threads waiting on a run-queue. 311 */ 312 static void 313 runq_print(struct runq *rq) 314 { 315 struct rqhead *rqh; 316 struct thread *td; 317 int pri; 318 int j; 319 int i; 320 321 for (i = 0; i < RQB_LEN; i++) { 322 printf("\t\trunq bits %d 0x%zx\n", 323 i, rq->rq_status.rqb_bits[i]); 324 for (j = 0; j < RQB_BPW; j++) 325 if (rq->rq_status.rqb_bits[i] & (1ul << j)) { 326 pri = j + (i << RQB_L2BPW); 327 rqh = &rq->rq_queues[pri]; 328 TAILQ_FOREACH(td, rqh, td_runq) { 329 printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n", 330 td, td->td_name, td->td_priority, 331 td->td_rqindex, pri); 332 } 333 } 334 } 335 } 336 337 /* 338 * Print the status of a per-cpu thread queue. Should be a ddb show cmd. 339 */ 340 void 341 tdq_print(int cpu) 342 { 343 struct tdq *tdq; 344 345 tdq = TDQ_CPU(cpu); 346 347 printf("tdq %d:\n", TDQ_ID(tdq)); 348 printf("\tlock %p\n", TDQ_LOCKPTR(tdq)); 349 printf("\tLock name: %s\n", tdq->tdq_name); 350 printf("\tload: %d\n", tdq->tdq_load); 351 printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt); 352 printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt); 353 printf("\tidle state: %d\n", tdq->tdq_idlestate); 354 printf("\ttimeshare idx: %d\n", tdq->tdq_idx); 355 printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx); 356 printf("\tload transferable: %d\n", tdq->tdq_transferable); 357 printf("\tlowest priority: %d\n", tdq->tdq_lowpri); 358 printf("\trealtime runq:\n"); 359 runq_print(&tdq->tdq_realtime); 360 printf("\ttimeshare runq:\n"); 361 runq_print(&tdq->tdq_timeshare); 362 printf("\tidle runq:\n"); 363 runq_print(&tdq->tdq_idle); 364 } 365 366 static inline int 367 sched_shouldpreempt(int pri, int cpri, int remote) 368 { 369 /* 370 * If the new priority is not better than the current priority there is 371 * nothing to do. 372 */ 373 if (pri >= cpri) 374 return (0); 375 /* 376 * Always preempt idle. 377 */ 378 if (cpri >= PRI_MIN_IDLE) 379 return (1); 380 /* 381 * If preemption is disabled don't preempt others. 382 */ 383 if (preempt_thresh == 0) 384 return (0); 385 /* 386 * Preempt if we exceed the threshold. 387 */ 388 if (pri <= preempt_thresh) 389 return (1); 390 /* 391 * If we're realtime or better and there is timeshare or worse running 392 * preempt only remote processors. 393 */ 394 if (remote && pri <= PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME) 395 return (1); 396 return (0); 397 } 398 399 #define TS_RQ_PPQ (((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS) 400 /* 401 * Add a thread to the actual run-queue. Keeps transferable counts up to 402 * date with what is actually on the run-queue. Selects the correct 403 * queue position for timeshare threads. 404 */ 405 static __inline void 406 tdq_runq_add(struct tdq *tdq, struct thread *td, int flags) 407 { 408 struct td_sched *ts; 409 u_char pri; 410 411 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 412 THREAD_LOCK_ASSERT(td, MA_OWNED); 413 414 pri = td->td_priority; 415 ts = td->td_sched; 416 TD_SET_RUNQ(td); 417 if (THREAD_CAN_MIGRATE(td)) { 418 tdq->tdq_transferable++; 419 ts->ts_flags |= TSF_XFERABLE; 420 } 421 if (pri <= PRI_MAX_REALTIME) { 422 ts->ts_runq = &tdq->tdq_realtime; 423 } else if (pri <= PRI_MAX_TIMESHARE) { 424 ts->ts_runq = &tdq->tdq_timeshare; 425 KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE, 426 ("Invalid priority %d on timeshare runq", pri)); 427 /* 428 * This queue contains only priorities between MIN and MAX 429 * realtime. Use the whole queue to represent these values. 430 */ 431 if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) { 432 pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ; 433 pri = (pri + tdq->tdq_idx) % RQ_NQS; 434 /* 435 * This effectively shortens the queue by one so we 436 * can have a one slot difference between idx and 437 * ridx while we wait for threads to drain. 438 */ 439 if (tdq->tdq_ridx != tdq->tdq_idx && 440 pri == tdq->tdq_ridx) 441 pri = (unsigned char)(pri - 1) % RQ_NQS; 442 } else 443 pri = tdq->tdq_ridx; 444 runq_add_pri(ts->ts_runq, td, pri, flags); 445 return; 446 } else 447 ts->ts_runq = &tdq->tdq_idle; 448 runq_add(ts->ts_runq, td, flags); 449 } 450 451 /* 452 * Remove a thread from a run-queue. This typically happens when a thread 453 * is selected to run. Running threads are not on the queue and the 454 * transferable count does not reflect them. 455 */ 456 static __inline void 457 tdq_runq_rem(struct tdq *tdq, struct thread *td) 458 { 459 struct td_sched *ts; 460 461 ts = td->td_sched; 462 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 463 KASSERT(ts->ts_runq != NULL, 464 ("tdq_runq_remove: thread %p null ts_runq", td)); 465 if (ts->ts_flags & TSF_XFERABLE) { 466 tdq->tdq_transferable--; 467 ts->ts_flags &= ~TSF_XFERABLE; 468 } 469 if (ts->ts_runq == &tdq->tdq_timeshare) { 470 if (tdq->tdq_idx != tdq->tdq_ridx) 471 runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx); 472 else 473 runq_remove_idx(ts->ts_runq, td, NULL); 474 } else 475 runq_remove(ts->ts_runq, td); 476 } 477 478 /* 479 * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load 480 * for this thread to the referenced thread queue. 481 */ 482 static void 483 tdq_load_add(struct tdq *tdq, struct thread *td) 484 { 485 486 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 487 THREAD_LOCK_ASSERT(td, MA_OWNED); 488 489 tdq->tdq_load++; 490 if ((td->td_proc->p_flag & P_NOLOAD) == 0) 491 tdq->tdq_sysload++; 492 CTR2(KTR_SCHED, "cpu %d load: %d", TDQ_ID(tdq), tdq->tdq_load); 493 } 494 495 /* 496 * Remove the load from a thread that is transitioning to a sleep state or 497 * exiting. 498 */ 499 static void 500 tdq_load_rem(struct tdq *tdq, struct thread *td) 501 { 502 503 THREAD_LOCK_ASSERT(td, MA_OWNED); 504 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 505 KASSERT(tdq->tdq_load != 0, 506 ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq))); 507 508 tdq->tdq_load--; 509 if ((td->td_proc->p_flag & P_NOLOAD) == 0) 510 tdq->tdq_sysload--; 511 CTR1(KTR_SCHED, "load: %d", tdq->tdq_load); 512 } 513 514 /* 515 * Set lowpri to its exact value by searching the run-queue and 516 * evaluating curthread. curthread may be passed as an optimization. 517 */ 518 static void 519 tdq_setlowpri(struct tdq *tdq, struct thread *ctd) 520 { 521 struct thread *td; 522 523 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 524 if (ctd == NULL) 525 ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread; 526 td = tdq_choose(tdq); 527 if (td == NULL || td->td_priority > ctd->td_priority) 528 tdq->tdq_lowpri = ctd->td_priority; 529 else 530 tdq->tdq_lowpri = td->td_priority; 531 } 532 533 #ifdef SMP 534 struct cpu_search { 535 cpumask_t cs_mask; /* Mask of valid cpus. */ 536 u_int cs_load; 537 u_int cs_cpu; 538 int cs_limit; /* Min priority for low min load for high. */ 539 }; 540 541 #define CPU_SEARCH_LOWEST 0x1 542 #define CPU_SEARCH_HIGHEST 0x2 543 #define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST) 544 545 #define CPUMASK_FOREACH(cpu, mask) \ 546 for ((cpu) = 0; (cpu) < sizeof((mask)) * 8; (cpu)++) \ 547 if ((mask) & 1 << (cpu)) 548 549 static __inline int cpu_search(struct cpu_group *cg, struct cpu_search *low, 550 struct cpu_search *high, const int match); 551 int cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low); 552 int cpu_search_highest(struct cpu_group *cg, struct cpu_search *high); 553 int cpu_search_both(struct cpu_group *cg, struct cpu_search *low, 554 struct cpu_search *high); 555 556 /* 557 * This routine compares according to the match argument and should be 558 * reduced in actual instantiations via constant propagation and dead code 559 * elimination. 560 */ 561 static __inline int 562 cpu_compare(int cpu, struct cpu_search *low, struct cpu_search *high, 563 const int match) 564 { 565 struct tdq *tdq; 566 567 tdq = TDQ_CPU(cpu); 568 if (match & CPU_SEARCH_LOWEST) 569 if (low->cs_mask & (1 << cpu) && 570 tdq->tdq_load < low->cs_load && 571 tdq->tdq_lowpri > low->cs_limit) { 572 low->cs_cpu = cpu; 573 low->cs_load = tdq->tdq_load; 574 } 575 if (match & CPU_SEARCH_HIGHEST) 576 if (high->cs_mask & (1 << cpu) && 577 tdq->tdq_load >= high->cs_limit && 578 tdq->tdq_load > high->cs_load && 579 tdq->tdq_transferable) { 580 high->cs_cpu = cpu; 581 high->cs_load = tdq->tdq_load; 582 } 583 return (tdq->tdq_load); 584 } 585 586 /* 587 * Search the tree of cpu_groups for the lowest or highest loaded cpu 588 * according to the match argument. This routine actually compares the 589 * load on all paths through the tree and finds the least loaded cpu on 590 * the least loaded path, which may differ from the least loaded cpu in 591 * the system. This balances work among caches and busses. 592 * 593 * This inline is instantiated in three forms below using constants for the 594 * match argument. It is reduced to the minimum set for each case. It is 595 * also recursive to the depth of the tree. 596 */ 597 static __inline int 598 cpu_search(struct cpu_group *cg, struct cpu_search *low, 599 struct cpu_search *high, const int match) 600 { 601 int total; 602 603 total = 0; 604 if (cg->cg_children) { 605 struct cpu_search lgroup; 606 struct cpu_search hgroup; 607 struct cpu_group *child; 608 u_int lload; 609 int hload; 610 int load; 611 int i; 612 613 lload = -1; 614 hload = -1; 615 for (i = 0; i < cg->cg_children; i++) { 616 child = &cg->cg_child[i]; 617 if (match & CPU_SEARCH_LOWEST) { 618 lgroup = *low; 619 lgroup.cs_load = -1; 620 } 621 if (match & CPU_SEARCH_HIGHEST) { 622 hgroup = *high; 623 lgroup.cs_load = 0; 624 } 625 switch (match) { 626 case CPU_SEARCH_LOWEST: 627 load = cpu_search_lowest(child, &lgroup); 628 break; 629 case CPU_SEARCH_HIGHEST: 630 load = cpu_search_highest(child, &hgroup); 631 break; 632 case CPU_SEARCH_BOTH: 633 load = cpu_search_both(child, &lgroup, &hgroup); 634 break; 635 } 636 total += load; 637 if (match & CPU_SEARCH_LOWEST) 638 if (load < lload || low->cs_cpu == -1) { 639 *low = lgroup; 640 lload = load; 641 } 642 if (match & CPU_SEARCH_HIGHEST) 643 if (load > hload || high->cs_cpu == -1) { 644 hload = load; 645 *high = hgroup; 646 } 647 } 648 } else { 649 int cpu; 650 651 CPUMASK_FOREACH(cpu, cg->cg_mask) 652 total += cpu_compare(cpu, low, high, match); 653 } 654 return (total); 655 } 656 657 /* 658 * cpu_search instantiations must pass constants to maintain the inline 659 * optimization. 660 */ 661 int 662 cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low) 663 { 664 return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST); 665 } 666 667 int 668 cpu_search_highest(struct cpu_group *cg, struct cpu_search *high) 669 { 670 return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST); 671 } 672 673 int 674 cpu_search_both(struct cpu_group *cg, struct cpu_search *low, 675 struct cpu_search *high) 676 { 677 return cpu_search(cg, low, high, CPU_SEARCH_BOTH); 678 } 679 680 /* 681 * Find the cpu with the least load via the least loaded path that has a 682 * lowpri greater than pri pri. A pri of -1 indicates any priority is 683 * acceptable. 684 */ 685 static inline int 686 sched_lowest(struct cpu_group *cg, cpumask_t mask, int pri) 687 { 688 struct cpu_search low; 689 690 low.cs_cpu = -1; 691 low.cs_load = -1; 692 low.cs_mask = mask; 693 low.cs_limit = pri; 694 cpu_search_lowest(cg, &low); 695 return low.cs_cpu; 696 } 697 698 /* 699 * Find the cpu with the highest load via the highest loaded path. 700 */ 701 static inline int 702 sched_highest(struct cpu_group *cg, cpumask_t mask, int minload) 703 { 704 struct cpu_search high; 705 706 high.cs_cpu = -1; 707 high.cs_load = 0; 708 high.cs_mask = mask; 709 high.cs_limit = minload; 710 cpu_search_highest(cg, &high); 711 return high.cs_cpu; 712 } 713 714 /* 715 * Simultaneously find the highest and lowest loaded cpu reachable via 716 * cg. 717 */ 718 static inline void 719 sched_both(struct cpu_group *cg, cpumask_t mask, int *lowcpu, int *highcpu) 720 { 721 struct cpu_search high; 722 struct cpu_search low; 723 724 low.cs_cpu = -1; 725 low.cs_limit = -1; 726 low.cs_load = -1; 727 low.cs_mask = mask; 728 high.cs_load = 0; 729 high.cs_cpu = -1; 730 high.cs_limit = -1; 731 high.cs_mask = mask; 732 cpu_search_both(cg, &low, &high); 733 *lowcpu = low.cs_cpu; 734 *highcpu = high.cs_cpu; 735 return; 736 } 737 738 static void 739 sched_balance_group(struct cpu_group *cg) 740 { 741 cpumask_t mask; 742 int high; 743 int low; 744 int i; 745 746 mask = -1; 747 for (;;) { 748 sched_both(cg, mask, &low, &high); 749 if (low == high || low == -1 || high == -1) 750 break; 751 if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low))) 752 break; 753 /* 754 * If we failed to move any threads determine which cpu 755 * to kick out of the set and try again. 756 */ 757 if (TDQ_CPU(high)->tdq_transferable == 0) 758 mask &= ~(1 << high); 759 else 760 mask &= ~(1 << low); 761 } 762 763 for (i = 0; i < cg->cg_children; i++) 764 sched_balance_group(&cg->cg_child[i]); 765 } 766 767 static void 768 sched_balance() 769 { 770 struct tdq *tdq; 771 772 /* 773 * Select a random time between .5 * balance_interval and 774 * 1.5 * balance_interval. 775 */ 776 balance_ticks = max(balance_interval / 2, 1); 777 balance_ticks += random() % balance_interval; 778 if (smp_started == 0 || rebalance == 0) 779 return; 780 tdq = TDQ_SELF(); 781 TDQ_UNLOCK(tdq); 782 sched_balance_group(cpu_top); 783 TDQ_LOCK(tdq); 784 } 785 786 /* 787 * Lock two thread queues using their address to maintain lock order. 788 */ 789 static void 790 tdq_lock_pair(struct tdq *one, struct tdq *two) 791 { 792 if (one < two) { 793 TDQ_LOCK(one); 794 TDQ_LOCK_FLAGS(two, MTX_DUPOK); 795 } else { 796 TDQ_LOCK(two); 797 TDQ_LOCK_FLAGS(one, MTX_DUPOK); 798 } 799 } 800 801 /* 802 * Unlock two thread queues. Order is not important here. 803 */ 804 static void 805 tdq_unlock_pair(struct tdq *one, struct tdq *two) 806 { 807 TDQ_UNLOCK(one); 808 TDQ_UNLOCK(two); 809 } 810 811 /* 812 * Transfer load between two imbalanced thread queues. 813 */ 814 static int 815 sched_balance_pair(struct tdq *high, struct tdq *low) 816 { 817 int transferable; 818 int high_load; 819 int low_load; 820 int moved; 821 int move; 822 int diff; 823 int i; 824 825 tdq_lock_pair(high, low); 826 transferable = high->tdq_transferable; 827 high_load = high->tdq_load; 828 low_load = low->tdq_load; 829 moved = 0; 830 /* 831 * Determine what the imbalance is and then adjust that to how many 832 * threads we actually have to give up (transferable). 833 */ 834 if (transferable != 0) { 835 diff = high_load - low_load; 836 move = diff / 2; 837 if (diff & 0x1) 838 move++; 839 move = min(move, transferable); 840 for (i = 0; i < move; i++) 841 moved += tdq_move(high, low); 842 /* 843 * IPI the target cpu to force it to reschedule with the new 844 * workload. 845 */ 846 ipi_selected(1 << TDQ_ID(low), IPI_PREEMPT); 847 } 848 tdq_unlock_pair(high, low); 849 return (moved); 850 } 851 852 /* 853 * Move a thread from one thread queue to another. 854 */ 855 static int 856 tdq_move(struct tdq *from, struct tdq *to) 857 { 858 struct td_sched *ts; 859 struct thread *td; 860 struct tdq *tdq; 861 int cpu; 862 863 TDQ_LOCK_ASSERT(from, MA_OWNED); 864 TDQ_LOCK_ASSERT(to, MA_OWNED); 865 866 tdq = from; 867 cpu = TDQ_ID(to); 868 td = tdq_steal(tdq, cpu); 869 if (td == NULL) 870 return (0); 871 ts = td->td_sched; 872 /* 873 * Although the run queue is locked the thread may be blocked. Lock 874 * it to clear this and acquire the run-queue lock. 875 */ 876 thread_lock(td); 877 /* Drop recursive lock on from acquired via thread_lock(). */ 878 TDQ_UNLOCK(from); 879 sched_rem(td); 880 ts->ts_cpu = cpu; 881 td->td_lock = TDQ_LOCKPTR(to); 882 tdq_add(to, td, SRQ_YIELDING); 883 return (1); 884 } 885 886 /* 887 * This tdq has idled. Try to steal a thread from another cpu and switch 888 * to it. 889 */ 890 static int 891 tdq_idled(struct tdq *tdq) 892 { 893 struct cpu_group *cg; 894 struct tdq *steal; 895 cpumask_t mask; 896 int thresh; 897 int cpu; 898 899 if (smp_started == 0 || steal_idle == 0) 900 return (1); 901 mask = -1; 902 mask &= ~PCPU_GET(cpumask); 903 /* We don't want to be preempted while we're iterating. */ 904 spinlock_enter(); 905 for (cg = tdq->tdq_cg; cg != NULL; ) { 906 if ((cg->cg_flags & (CG_FLAG_HTT | CG_FLAG_THREAD)) == 0) 907 thresh = steal_thresh; 908 else 909 thresh = 1; 910 cpu = sched_highest(cg, mask, thresh); 911 if (cpu == -1) { 912 cg = cg->cg_parent; 913 continue; 914 } 915 steal = TDQ_CPU(cpu); 916 mask &= ~(1 << cpu); 917 tdq_lock_pair(tdq, steal); 918 if (steal->tdq_load < thresh || steal->tdq_transferable == 0) { 919 tdq_unlock_pair(tdq, steal); 920 continue; 921 } 922 /* 923 * If a thread was added while interrupts were disabled don't 924 * steal one here. If we fail to acquire one due to affinity 925 * restrictions loop again with this cpu removed from the 926 * set. 927 */ 928 if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) { 929 tdq_unlock_pair(tdq, steal); 930 continue; 931 } 932 spinlock_exit(); 933 TDQ_UNLOCK(steal); 934 mi_switch(SW_VOL | SWT_IDLE, NULL); 935 thread_unlock(curthread); 936 937 return (0); 938 } 939 spinlock_exit(); 940 return (1); 941 } 942 943 /* 944 * Notify a remote cpu of new work. Sends an IPI if criteria are met. 945 */ 946 static void 947 tdq_notify(struct tdq *tdq, struct thread *td) 948 { 949 struct thread *ctd; 950 int pri; 951 int cpu; 952 953 if (tdq->tdq_ipipending) 954 return; 955 cpu = td->td_sched->ts_cpu; 956 pri = td->td_priority; 957 ctd = pcpu_find(cpu)->pc_curthread; 958 if (!sched_shouldpreempt(pri, ctd->td_priority, 1)) 959 return; 960 if (TD_IS_IDLETHREAD(ctd)) { 961 /* 962 * If the idle thread is still 'running' it's probably 963 * waiting on us to release the tdq spinlock already. No 964 * need to ipi. 965 */ 966 if (tdq->tdq_idlestate == TDQ_RUNNING) 967 return; 968 /* 969 * If the MD code has an idle wakeup routine try that before 970 * falling back to IPI. 971 */ 972 if (cpu_idle_wakeup(cpu)) 973 return; 974 } 975 tdq->tdq_ipipending = 1; 976 ipi_selected(1 << cpu, IPI_PREEMPT); 977 } 978 979 /* 980 * Steals load from a timeshare queue. Honors the rotating queue head 981 * index. 982 */ 983 static struct thread * 984 runq_steal_from(struct runq *rq, int cpu, u_char start) 985 { 986 struct rqbits *rqb; 987 struct rqhead *rqh; 988 struct thread *td; 989 int first; 990 int bit; 991 int pri; 992 int i; 993 994 rqb = &rq->rq_status; 995 bit = start & (RQB_BPW -1); 996 pri = 0; 997 first = 0; 998 again: 999 for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) { 1000 if (rqb->rqb_bits[i] == 0) 1001 continue; 1002 if (bit != 0) { 1003 for (pri = bit; pri < RQB_BPW; pri++) 1004 if (rqb->rqb_bits[i] & (1ul << pri)) 1005 break; 1006 if (pri >= RQB_BPW) 1007 continue; 1008 } else 1009 pri = RQB_FFS(rqb->rqb_bits[i]); 1010 pri += (i << RQB_L2BPW); 1011 rqh = &rq->rq_queues[pri]; 1012 TAILQ_FOREACH(td, rqh, td_runq) { 1013 if (first && THREAD_CAN_MIGRATE(td) && 1014 THREAD_CAN_SCHED(td, cpu)) 1015 return (td); 1016 first = 1; 1017 } 1018 } 1019 if (start != 0) { 1020 start = 0; 1021 goto again; 1022 } 1023 1024 return (NULL); 1025 } 1026 1027 /* 1028 * Steals load from a standard linear queue. 1029 */ 1030 static struct thread * 1031 runq_steal(struct runq *rq, int cpu) 1032 { 1033 struct rqhead *rqh; 1034 struct rqbits *rqb; 1035 struct thread *td; 1036 int word; 1037 int bit; 1038 1039 rqb = &rq->rq_status; 1040 for (word = 0; word < RQB_LEN; word++) { 1041 if (rqb->rqb_bits[word] == 0) 1042 continue; 1043 for (bit = 0; bit < RQB_BPW; bit++) { 1044 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) 1045 continue; 1046 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; 1047 TAILQ_FOREACH(td, rqh, td_runq) 1048 if (THREAD_CAN_MIGRATE(td) && 1049 THREAD_CAN_SCHED(td, cpu)) 1050 return (td); 1051 } 1052 } 1053 return (NULL); 1054 } 1055 1056 /* 1057 * Attempt to steal a thread in priority order from a thread queue. 1058 */ 1059 static struct thread * 1060 tdq_steal(struct tdq *tdq, int cpu) 1061 { 1062 struct thread *td; 1063 1064 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1065 if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL) 1066 return (td); 1067 if ((td = runq_steal_from(&tdq->tdq_timeshare, 1068 cpu, tdq->tdq_ridx)) != NULL) 1069 return (td); 1070 return (runq_steal(&tdq->tdq_idle, cpu)); 1071 } 1072 1073 /* 1074 * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the 1075 * current lock and returns with the assigned queue locked. 1076 */ 1077 static inline struct tdq * 1078 sched_setcpu(struct thread *td, int cpu, int flags) 1079 { 1080 1081 struct tdq *tdq; 1082 1083 THREAD_LOCK_ASSERT(td, MA_OWNED); 1084 tdq = TDQ_CPU(cpu); 1085 td->td_sched->ts_cpu = cpu; 1086 /* 1087 * If the lock matches just return the queue. 1088 */ 1089 if (td->td_lock == TDQ_LOCKPTR(tdq)) 1090 return (tdq); 1091 #ifdef notyet 1092 /* 1093 * If the thread isn't running its lockptr is a 1094 * turnstile or a sleepqueue. We can just lock_set without 1095 * blocking. 1096 */ 1097 if (TD_CAN_RUN(td)) { 1098 TDQ_LOCK(tdq); 1099 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 1100 return (tdq); 1101 } 1102 #endif 1103 /* 1104 * The hard case, migration, we need to block the thread first to 1105 * prevent order reversals with other cpus locks. 1106 */ 1107 thread_lock_block(td); 1108 TDQ_LOCK(tdq); 1109 thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); 1110 return (tdq); 1111 } 1112 1113 SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding"); 1114 SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity"); 1115 SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity"); 1116 SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load"); 1117 SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu"); 1118 SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration"); 1119 1120 static int 1121 sched_pickcpu(struct thread *td, int flags) 1122 { 1123 struct cpu_group *cg; 1124 struct td_sched *ts; 1125 struct tdq *tdq; 1126 cpumask_t mask; 1127 int self; 1128 int pri; 1129 int cpu; 1130 1131 self = PCPU_GET(cpuid); 1132 ts = td->td_sched; 1133 if (smp_started == 0) 1134 return (self); 1135 /* 1136 * Don't migrate a running thread from sched_switch(). 1137 */ 1138 if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td)) 1139 return (ts->ts_cpu); 1140 /* 1141 * Prefer to run interrupt threads on the processors that generate 1142 * the interrupt. 1143 */ 1144 if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) && 1145 curthread->td_intr_nesting_level && ts->ts_cpu != self) { 1146 SCHED_STAT_INC(pickcpu_intrbind); 1147 ts->ts_cpu = self; 1148 } 1149 /* 1150 * If the thread can run on the last cpu and the affinity has not 1151 * expired or it is idle run it there. 1152 */ 1153 pri = td->td_priority; 1154 tdq = TDQ_CPU(ts->ts_cpu); 1155 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) { 1156 if (tdq->tdq_lowpri > PRI_MIN_IDLE) { 1157 SCHED_STAT_INC(pickcpu_idle_affinity); 1158 return (ts->ts_cpu); 1159 } 1160 if (SCHED_AFFINITY(ts, CG_SHARE_L2) && tdq->tdq_lowpri > pri) { 1161 SCHED_STAT_INC(pickcpu_affinity); 1162 return (ts->ts_cpu); 1163 } 1164 } 1165 /* 1166 * Search for the highest level in the tree that still has affinity. 1167 */ 1168 cg = NULL; 1169 for (cg = tdq->tdq_cg; cg != NULL; cg = cg->cg_parent) 1170 if (SCHED_AFFINITY(ts, cg->cg_level)) 1171 break; 1172 cpu = -1; 1173 mask = td->td_cpuset->cs_mask.__bits[0]; 1174 if (cg) 1175 cpu = sched_lowest(cg, mask, pri); 1176 if (cpu == -1) 1177 cpu = sched_lowest(cpu_top, mask, -1); 1178 /* 1179 * Compare the lowest loaded cpu to current cpu. 1180 */ 1181 if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri && 1182 TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE) { 1183 SCHED_STAT_INC(pickcpu_local); 1184 cpu = self; 1185 } else 1186 SCHED_STAT_INC(pickcpu_lowest); 1187 if (cpu != ts->ts_cpu) 1188 SCHED_STAT_INC(pickcpu_migration); 1189 KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu.")); 1190 return (cpu); 1191 } 1192 #endif 1193 1194 /* 1195 * Pick the highest priority task we have and return it. 1196 */ 1197 static struct thread * 1198 tdq_choose(struct tdq *tdq) 1199 { 1200 struct thread *td; 1201 1202 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1203 td = runq_choose(&tdq->tdq_realtime); 1204 if (td != NULL) 1205 return (td); 1206 td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); 1207 if (td != NULL) { 1208 KASSERT(td->td_priority >= PRI_MIN_TIMESHARE, 1209 ("tdq_choose: Invalid priority on timeshare queue %d", 1210 td->td_priority)); 1211 return (td); 1212 } 1213 td = runq_choose(&tdq->tdq_idle); 1214 if (td != NULL) { 1215 KASSERT(td->td_priority >= PRI_MIN_IDLE, 1216 ("tdq_choose: Invalid priority on idle queue %d", 1217 td->td_priority)); 1218 return (td); 1219 } 1220 1221 return (NULL); 1222 } 1223 1224 /* 1225 * Initialize a thread queue. 1226 */ 1227 static void 1228 tdq_setup(struct tdq *tdq) 1229 { 1230 1231 if (bootverbose) 1232 printf("ULE: setup cpu %d\n", TDQ_ID(tdq)); 1233 runq_init(&tdq->tdq_realtime); 1234 runq_init(&tdq->tdq_timeshare); 1235 runq_init(&tdq->tdq_idle); 1236 snprintf(tdq->tdq_name, sizeof(tdq->tdq_name), 1237 "sched lock %d", (int)TDQ_ID(tdq)); 1238 mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock", 1239 MTX_SPIN | MTX_RECURSE); 1240 } 1241 1242 #ifdef SMP 1243 static void 1244 sched_setup_smp(void) 1245 { 1246 struct tdq *tdq; 1247 int i; 1248 1249 cpu_top = smp_topo(); 1250 for (i = 0; i < MAXCPU; i++) { 1251 if (CPU_ABSENT(i)) 1252 continue; 1253 tdq = TDQ_CPU(i); 1254 tdq_setup(tdq); 1255 tdq->tdq_cg = smp_topo_find(cpu_top, i); 1256 if (tdq->tdq_cg == NULL) 1257 panic("Can't find cpu group for %d\n", i); 1258 } 1259 balance_tdq = TDQ_SELF(); 1260 sched_balance(); 1261 } 1262 #endif 1263 1264 /* 1265 * Setup the thread queues and initialize the topology based on MD 1266 * information. 1267 */ 1268 static void 1269 sched_setup(void *dummy) 1270 { 1271 struct tdq *tdq; 1272 1273 tdq = TDQ_SELF(); 1274 #ifdef SMP 1275 sched_setup_smp(); 1276 #else 1277 tdq_setup(tdq); 1278 #endif 1279 /* 1280 * To avoid divide-by-zero, we set realstathz a dummy value 1281 * in case which sched_clock() called before sched_initticks(). 1282 */ 1283 realstathz = hz; 1284 sched_slice = (realstathz/10); /* ~100ms */ 1285 tickincr = 1 << SCHED_TICK_SHIFT; 1286 1287 /* Add thread0's load since it's running. */ 1288 TDQ_LOCK(tdq); 1289 thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1290 tdq_load_add(tdq, &thread0); 1291 tdq->tdq_lowpri = thread0.td_priority; 1292 TDQ_UNLOCK(tdq); 1293 } 1294 1295 /* 1296 * This routine determines the tickincr after stathz and hz are setup. 1297 */ 1298 /* ARGSUSED */ 1299 static void 1300 sched_initticks(void *dummy) 1301 { 1302 int incr; 1303 1304 realstathz = stathz ? stathz : hz; 1305 sched_slice = (realstathz/10); /* ~100ms */ 1306 1307 /* 1308 * tickincr is shifted out by 10 to avoid rounding errors due to 1309 * hz not being evenly divisible by stathz on all platforms. 1310 */ 1311 incr = (hz << SCHED_TICK_SHIFT) / realstathz; 1312 /* 1313 * This does not work for values of stathz that are more than 1314 * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen. 1315 */ 1316 if (incr == 0) 1317 incr = 1; 1318 tickincr = incr; 1319 #ifdef SMP 1320 /* 1321 * Set the default balance interval now that we know 1322 * what realstathz is. 1323 */ 1324 balance_interval = realstathz; 1325 /* 1326 * Set steal thresh to log2(mp_ncpu) but no greater than 4. This 1327 * prevents excess thrashing on large machines and excess idle on 1328 * smaller machines. 1329 */ 1330 steal_thresh = min(ffs(mp_ncpus) - 1, 3); 1331 affinity = SCHED_AFFINITY_DEFAULT; 1332 #endif 1333 } 1334 1335 1336 /* 1337 * This is the core of the interactivity algorithm. Determines a score based 1338 * on past behavior. It is the ratio of sleep time to run time scaled to 1339 * a [0, 100] integer. This is the voluntary sleep time of a process, which 1340 * differs from the cpu usage because it does not account for time spent 1341 * waiting on a run-queue. Would be prettier if we had floating point. 1342 */ 1343 static int 1344 sched_interact_score(struct thread *td) 1345 { 1346 struct td_sched *ts; 1347 int div; 1348 1349 ts = td->td_sched; 1350 /* 1351 * The score is only needed if this is likely to be an interactive 1352 * task. Don't go through the expense of computing it if there's 1353 * no chance. 1354 */ 1355 if (sched_interact <= SCHED_INTERACT_HALF && 1356 ts->ts_runtime >= ts->ts_slptime) 1357 return (SCHED_INTERACT_HALF); 1358 1359 if (ts->ts_runtime > ts->ts_slptime) { 1360 div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF); 1361 return (SCHED_INTERACT_HALF + 1362 (SCHED_INTERACT_HALF - (ts->ts_slptime / div))); 1363 } 1364 if (ts->ts_slptime > ts->ts_runtime) { 1365 div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF); 1366 return (ts->ts_runtime / div); 1367 } 1368 /* runtime == slptime */ 1369 if (ts->ts_runtime) 1370 return (SCHED_INTERACT_HALF); 1371 1372 /* 1373 * This can happen if slptime and runtime are 0. 1374 */ 1375 return (0); 1376 1377 } 1378 1379 /* 1380 * Scale the scheduling priority according to the "interactivity" of this 1381 * process. 1382 */ 1383 static void 1384 sched_priority(struct thread *td) 1385 { 1386 int score; 1387 int pri; 1388 1389 if (td->td_pri_class != PRI_TIMESHARE) 1390 return; 1391 /* 1392 * If the score is interactive we place the thread in the realtime 1393 * queue with a priority that is less than kernel and interrupt 1394 * priorities. These threads are not subject to nice restrictions. 1395 * 1396 * Scores greater than this are placed on the normal timeshare queue 1397 * where the priority is partially decided by the most recent cpu 1398 * utilization and the rest is decided by nice value. 1399 * 1400 * The nice value of the process has a linear effect on the calculated 1401 * score. Negative nice values make it easier for a thread to be 1402 * considered interactive. 1403 */ 1404 score = imax(0, sched_interact_score(td) - td->td_proc->p_nice); 1405 if (score < sched_interact) { 1406 pri = PRI_MIN_REALTIME; 1407 pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME) / sched_interact) 1408 * score; 1409 KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME, 1410 ("sched_priority: invalid interactive priority %d score %d", 1411 pri, score)); 1412 } else { 1413 pri = SCHED_PRI_MIN; 1414 if (td->td_sched->ts_ticks) 1415 pri += SCHED_PRI_TICKS(td->td_sched); 1416 pri += SCHED_PRI_NICE(td->td_proc->p_nice); 1417 KASSERT(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE, 1418 ("sched_priority: invalid priority %d: nice %d, " 1419 "ticks %d ftick %d ltick %d tick pri %d", 1420 pri, td->td_proc->p_nice, td->td_sched->ts_ticks, 1421 td->td_sched->ts_ftick, td->td_sched->ts_ltick, 1422 SCHED_PRI_TICKS(td->td_sched))); 1423 } 1424 sched_user_prio(td, pri); 1425 1426 return; 1427 } 1428 1429 /* 1430 * This routine enforces a maximum limit on the amount of scheduling history 1431 * kept. It is called after either the slptime or runtime is adjusted. This 1432 * function is ugly due to integer math. 1433 */ 1434 static void 1435 sched_interact_update(struct thread *td) 1436 { 1437 struct td_sched *ts; 1438 u_int sum; 1439 1440 ts = td->td_sched; 1441 sum = ts->ts_runtime + ts->ts_slptime; 1442 if (sum < SCHED_SLP_RUN_MAX) 1443 return; 1444 /* 1445 * This only happens from two places: 1446 * 1) We have added an unusual amount of run time from fork_exit. 1447 * 2) We have added an unusual amount of sleep time from sched_sleep(). 1448 */ 1449 if (sum > SCHED_SLP_RUN_MAX * 2) { 1450 if (ts->ts_runtime > ts->ts_slptime) { 1451 ts->ts_runtime = SCHED_SLP_RUN_MAX; 1452 ts->ts_slptime = 1; 1453 } else { 1454 ts->ts_slptime = SCHED_SLP_RUN_MAX; 1455 ts->ts_runtime = 1; 1456 } 1457 return; 1458 } 1459 /* 1460 * If we have exceeded by more than 1/5th then the algorithm below 1461 * will not bring us back into range. Dividing by two here forces 1462 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] 1463 */ 1464 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { 1465 ts->ts_runtime /= 2; 1466 ts->ts_slptime /= 2; 1467 return; 1468 } 1469 ts->ts_runtime = (ts->ts_runtime / 5) * 4; 1470 ts->ts_slptime = (ts->ts_slptime / 5) * 4; 1471 } 1472 1473 /* 1474 * Scale back the interactivity history when a child thread is created. The 1475 * history is inherited from the parent but the thread may behave totally 1476 * differently. For example, a shell spawning a compiler process. We want 1477 * to learn that the compiler is behaving badly very quickly. 1478 */ 1479 static void 1480 sched_interact_fork(struct thread *td) 1481 { 1482 int ratio; 1483 int sum; 1484 1485 sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime; 1486 if (sum > SCHED_SLP_RUN_FORK) { 1487 ratio = sum / SCHED_SLP_RUN_FORK; 1488 td->td_sched->ts_runtime /= ratio; 1489 td->td_sched->ts_slptime /= ratio; 1490 } 1491 } 1492 1493 /* 1494 * Called from proc0_init() to setup the scheduler fields. 1495 */ 1496 void 1497 schedinit(void) 1498 { 1499 1500 /* 1501 * Set up the scheduler specific parts of proc0. 1502 */ 1503 proc0.p_sched = NULL; /* XXX */ 1504 thread0.td_sched = &td_sched0; 1505 td_sched0.ts_ltick = ticks; 1506 td_sched0.ts_ftick = ticks; 1507 td_sched0.ts_slice = sched_slice; 1508 } 1509 1510 /* 1511 * This is only somewhat accurate since given many processes of the same 1512 * priority they will switch when their slices run out, which will be 1513 * at most sched_slice stathz ticks. 1514 */ 1515 int 1516 sched_rr_interval(void) 1517 { 1518 1519 /* Convert sched_slice to hz */ 1520 return (hz/(realstathz/sched_slice)); 1521 } 1522 1523 /* 1524 * Update the percent cpu tracking information when it is requested or 1525 * the total history exceeds the maximum. We keep a sliding history of 1526 * tick counts that slowly decays. This is less precise than the 4BSD 1527 * mechanism since it happens with less regular and frequent events. 1528 */ 1529 static void 1530 sched_pctcpu_update(struct td_sched *ts) 1531 { 1532 1533 if (ts->ts_ticks == 0) 1534 return; 1535 if (ticks - (hz / 10) < ts->ts_ltick && 1536 SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX) 1537 return; 1538 /* 1539 * Adjust counters and watermark for pctcpu calc. 1540 */ 1541 if (ts->ts_ltick > ticks - SCHED_TICK_TARG) 1542 ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) * 1543 SCHED_TICK_TARG; 1544 else 1545 ts->ts_ticks = 0; 1546 ts->ts_ltick = ticks; 1547 ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG; 1548 } 1549 1550 /* 1551 * Adjust the priority of a thread. Move it to the appropriate run-queue 1552 * if necessary. This is the back-end for several priority related 1553 * functions. 1554 */ 1555 static void 1556 sched_thread_priority(struct thread *td, u_char prio) 1557 { 1558 struct td_sched *ts; 1559 struct tdq *tdq; 1560 int oldpri; 1561 1562 CTR6(KTR_SCHED, "sched_prio: %p(%s) prio %d newprio %d by %p(%s)", 1563 td, td->td_name, td->td_priority, prio, curthread, 1564 curthread->td_name); 1565 ts = td->td_sched; 1566 THREAD_LOCK_ASSERT(td, MA_OWNED); 1567 if (td->td_priority == prio) 1568 return; 1569 /* 1570 * If the priority has been elevated due to priority 1571 * propagation, we may have to move ourselves to a new 1572 * queue. This could be optimized to not re-add in some 1573 * cases. 1574 */ 1575 if (TD_ON_RUNQ(td) && prio < td->td_priority) { 1576 sched_rem(td); 1577 td->td_priority = prio; 1578 sched_add(td, SRQ_BORROWING); 1579 return; 1580 } 1581 /* 1582 * If the thread is currently running we may have to adjust the lowpri 1583 * information so other cpus are aware of our current priority. 1584 */ 1585 if (TD_IS_RUNNING(td)) { 1586 tdq = TDQ_CPU(ts->ts_cpu); 1587 oldpri = td->td_priority; 1588 td->td_priority = prio; 1589 if (prio < tdq->tdq_lowpri) 1590 tdq->tdq_lowpri = prio; 1591 else if (tdq->tdq_lowpri == oldpri) 1592 tdq_setlowpri(tdq, td); 1593 return; 1594 } 1595 td->td_priority = prio; 1596 } 1597 1598 /* 1599 * Update a thread's priority when it is lent another thread's 1600 * priority. 1601 */ 1602 void 1603 sched_lend_prio(struct thread *td, u_char prio) 1604 { 1605 1606 td->td_flags |= TDF_BORROWING; 1607 sched_thread_priority(td, prio); 1608 } 1609 1610 /* 1611 * Restore a thread's priority when priority propagation is 1612 * over. The prio argument is the minimum priority the thread 1613 * needs to have to satisfy other possible priority lending 1614 * requests. If the thread's regular priority is less 1615 * important than prio, the thread will keep a priority boost 1616 * of prio. 1617 */ 1618 void 1619 sched_unlend_prio(struct thread *td, u_char prio) 1620 { 1621 u_char base_pri; 1622 1623 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 1624 td->td_base_pri <= PRI_MAX_TIMESHARE) 1625 base_pri = td->td_user_pri; 1626 else 1627 base_pri = td->td_base_pri; 1628 if (prio >= base_pri) { 1629 td->td_flags &= ~TDF_BORROWING; 1630 sched_thread_priority(td, base_pri); 1631 } else 1632 sched_lend_prio(td, prio); 1633 } 1634 1635 /* 1636 * Standard entry for setting the priority to an absolute value. 1637 */ 1638 void 1639 sched_prio(struct thread *td, u_char prio) 1640 { 1641 u_char oldprio; 1642 1643 /* First, update the base priority. */ 1644 td->td_base_pri = prio; 1645 1646 /* 1647 * If the thread is borrowing another thread's priority, don't 1648 * ever lower the priority. 1649 */ 1650 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 1651 return; 1652 1653 /* Change the real priority. */ 1654 oldprio = td->td_priority; 1655 sched_thread_priority(td, prio); 1656 1657 /* 1658 * If the thread is on a turnstile, then let the turnstile update 1659 * its state. 1660 */ 1661 if (TD_ON_LOCK(td) && oldprio != prio) 1662 turnstile_adjust(td, oldprio); 1663 } 1664 1665 /* 1666 * Set the base user priority, does not effect current running priority. 1667 */ 1668 void 1669 sched_user_prio(struct thread *td, u_char prio) 1670 { 1671 u_char oldprio; 1672 1673 td->td_base_user_pri = prio; 1674 if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio) 1675 return; 1676 oldprio = td->td_user_pri; 1677 td->td_user_pri = prio; 1678 } 1679 1680 void 1681 sched_lend_user_prio(struct thread *td, u_char prio) 1682 { 1683 u_char oldprio; 1684 1685 THREAD_LOCK_ASSERT(td, MA_OWNED); 1686 td->td_flags |= TDF_UBORROWING; 1687 oldprio = td->td_user_pri; 1688 td->td_user_pri = prio; 1689 } 1690 1691 void 1692 sched_unlend_user_prio(struct thread *td, u_char prio) 1693 { 1694 u_char base_pri; 1695 1696 THREAD_LOCK_ASSERT(td, MA_OWNED); 1697 base_pri = td->td_base_user_pri; 1698 if (prio >= base_pri) { 1699 td->td_flags &= ~TDF_UBORROWING; 1700 sched_user_prio(td, base_pri); 1701 } else { 1702 sched_lend_user_prio(td, prio); 1703 } 1704 } 1705 1706 /* 1707 * Block a thread for switching. Similar to thread_block() but does not 1708 * bump the spin count. 1709 */ 1710 static inline struct mtx * 1711 thread_block_switch(struct thread *td) 1712 { 1713 struct mtx *lock; 1714 1715 THREAD_LOCK_ASSERT(td, MA_OWNED); 1716 lock = td->td_lock; 1717 td->td_lock = &blocked_lock; 1718 mtx_unlock_spin(lock); 1719 1720 return (lock); 1721 } 1722 1723 /* 1724 * Handle migration from sched_switch(). This happens only for 1725 * cpu binding. 1726 */ 1727 static struct mtx * 1728 sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) 1729 { 1730 struct tdq *tdn; 1731 1732 tdn = TDQ_CPU(td->td_sched->ts_cpu); 1733 #ifdef SMP 1734 tdq_load_rem(tdq, td); 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(tdn, td); 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 * Release a thread that was blocked with thread_block_switch(). 1762 */ 1763 static inline void 1764 thread_unblock_switch(struct thread *td, struct mtx *mtx) 1765 { 1766 atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock, 1767 (uintptr_t)mtx); 1768 } 1769 1770 /* 1771 * Switch threads. This function has to handle threads coming in while 1772 * blocked for some reason, running, or idle. It also must deal with 1773 * migrating a thread from one queue to another as running threads may 1774 * be assigned elsewhere via binding. 1775 */ 1776 void 1777 sched_switch(struct thread *td, struct thread *newtd, int flags) 1778 { 1779 struct tdq *tdq; 1780 struct td_sched *ts; 1781 struct mtx *mtx; 1782 int srqflag; 1783 int cpuid; 1784 1785 THREAD_LOCK_ASSERT(td, MA_OWNED); 1786 KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument")); 1787 1788 cpuid = PCPU_GET(cpuid); 1789 tdq = TDQ_CPU(cpuid); 1790 ts = td->td_sched; 1791 mtx = td->td_lock; 1792 ts->ts_rltick = ticks; 1793 td->td_lastcpu = td->td_oncpu; 1794 td->td_oncpu = NOCPU; 1795 td->td_flags &= ~TDF_NEEDRESCHED; 1796 td->td_owepreempt = 0; 1797 tdq->tdq_switchcnt++; 1798 /* 1799 * The lock pointer in an idle thread should never change. Reset it 1800 * to CAN_RUN as well. 1801 */ 1802 if (TD_IS_IDLETHREAD(td)) { 1803 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1804 TD_SET_CAN_RUN(td); 1805 } else if (TD_IS_RUNNING(td)) { 1806 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1807 srqflag = (flags & SW_PREEMPT) ? 1808 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1809 SRQ_OURSELF|SRQ_YIELDING; 1810 if (ts->ts_cpu == cpuid) 1811 tdq_runq_add(tdq, td, srqflag); 1812 else 1813 mtx = sched_switch_migrate(tdq, td, srqflag); 1814 } else { 1815 /* This thread must be going to sleep. */ 1816 TDQ_LOCK(tdq); 1817 mtx = thread_block_switch(td); 1818 tdq_load_rem(tdq, td); 1819 } 1820 /* 1821 * We enter here with the thread blocked and assigned to the 1822 * appropriate cpu run-queue or sleep-queue and with the current 1823 * thread-queue locked. 1824 */ 1825 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 1826 newtd = choosethread(); 1827 /* 1828 * Call the MD code to switch contexts if necessary. 1829 */ 1830 if (td != newtd) { 1831 #ifdef HWPMC_HOOKS 1832 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1833 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1834 #endif 1835 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 1836 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 1837 1838 #ifdef KDTRACE_HOOKS 1839 /* 1840 * If DTrace has set the active vtime enum to anything 1841 * other than INACTIVE (0), then it should have set the 1842 * function to call. 1843 */ 1844 if (dtrace_vtime_active) 1845 (*dtrace_vtime_switch_func)(newtd); 1846 #endif 1847 1848 cpu_switch(td, newtd, mtx); 1849 /* 1850 * We may return from cpu_switch on a different cpu. However, 1851 * we always return with td_lock pointing to the current cpu's 1852 * run queue lock. 1853 */ 1854 cpuid = PCPU_GET(cpuid); 1855 tdq = TDQ_CPU(cpuid); 1856 lock_profile_obtain_lock_success( 1857 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 1858 #ifdef HWPMC_HOOKS 1859 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1860 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1861 #endif 1862 } else 1863 thread_unblock_switch(td, mtx); 1864 /* 1865 * Assert that all went well and return. 1866 */ 1867 TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED); 1868 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1869 td->td_oncpu = cpuid; 1870 } 1871 1872 /* 1873 * Adjust thread priorities as a result of a nice request. 1874 */ 1875 void 1876 sched_nice(struct proc *p, int nice) 1877 { 1878 struct thread *td; 1879 1880 PROC_LOCK_ASSERT(p, MA_OWNED); 1881 1882 p->p_nice = nice; 1883 FOREACH_THREAD_IN_PROC(p, td) { 1884 thread_lock(td); 1885 sched_priority(td); 1886 sched_prio(td, td->td_base_user_pri); 1887 thread_unlock(td); 1888 } 1889 } 1890 1891 /* 1892 * Record the sleep time for the interactivity scorer. 1893 */ 1894 void 1895 sched_sleep(struct thread *td, int prio) 1896 { 1897 1898 THREAD_LOCK_ASSERT(td, MA_OWNED); 1899 1900 td->td_slptick = ticks; 1901 if (TD_IS_SUSPENDED(td) || prio <= PSOCK) 1902 td->td_flags |= TDF_CANSWAP; 1903 if (static_boost == 1 && prio) 1904 sched_prio(td, prio); 1905 else if (static_boost && td->td_priority > static_boost) 1906 sched_prio(td, static_boost); 1907 } 1908 1909 /* 1910 * Schedule a thread to resume execution and record how long it voluntarily 1911 * slept. We also update the pctcpu, interactivity, and priority. 1912 */ 1913 void 1914 sched_wakeup(struct thread *td) 1915 { 1916 struct td_sched *ts; 1917 int slptick; 1918 1919 THREAD_LOCK_ASSERT(td, MA_OWNED); 1920 ts = td->td_sched; 1921 td->td_flags &= ~TDF_CANSWAP; 1922 /* 1923 * If we slept for more than a tick update our interactivity and 1924 * priority. 1925 */ 1926 slptick = td->td_slptick; 1927 td->td_slptick = 0; 1928 if (slptick && slptick != ticks) { 1929 u_int hzticks; 1930 1931 hzticks = (ticks - slptick) << SCHED_TICK_SHIFT; 1932 ts->ts_slptime += hzticks; 1933 sched_interact_update(td); 1934 sched_pctcpu_update(ts); 1935 } 1936 /* Reset the slice value after we sleep. */ 1937 ts->ts_slice = sched_slice; 1938 sched_add(td, SRQ_BORING); 1939 } 1940 1941 /* 1942 * Penalize the parent for creating a new child and initialize the child's 1943 * priority. 1944 */ 1945 void 1946 sched_fork(struct thread *td, struct thread *child) 1947 { 1948 THREAD_LOCK_ASSERT(td, MA_OWNED); 1949 sched_fork_thread(td, child); 1950 /* 1951 * Penalize the parent and child for forking. 1952 */ 1953 sched_interact_fork(child); 1954 sched_priority(child); 1955 td->td_sched->ts_runtime += tickincr; 1956 sched_interact_update(td); 1957 sched_priority(td); 1958 } 1959 1960 /* 1961 * Fork a new thread, may be within the same process. 1962 */ 1963 void 1964 sched_fork_thread(struct thread *td, struct thread *child) 1965 { 1966 struct td_sched *ts; 1967 struct td_sched *ts2; 1968 1969 THREAD_LOCK_ASSERT(td, MA_OWNED); 1970 /* 1971 * Initialize child. 1972 */ 1973 ts = td->td_sched; 1974 ts2 = child->td_sched; 1975 child->td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1976 child->td_cpuset = cpuset_ref(td->td_cpuset); 1977 ts2->ts_cpu = ts->ts_cpu; 1978 ts2->ts_flags = 0; 1979 /* 1980 * Grab our parents cpu estimation information and priority. 1981 */ 1982 ts2->ts_ticks = ts->ts_ticks; 1983 ts2->ts_ltick = ts->ts_ltick; 1984 ts2->ts_ftick = ts->ts_ftick; 1985 child->td_user_pri = td->td_user_pri; 1986 child->td_base_user_pri = td->td_base_user_pri; 1987 /* 1988 * And update interactivity score. 1989 */ 1990 ts2->ts_slptime = ts->ts_slptime; 1991 ts2->ts_runtime = ts->ts_runtime; 1992 ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */ 1993 } 1994 1995 /* 1996 * Adjust the priority class of a thread. 1997 */ 1998 void 1999 sched_class(struct thread *td, int class) 2000 { 2001 2002 THREAD_LOCK_ASSERT(td, MA_OWNED); 2003 if (td->td_pri_class == class) 2004 return; 2005 td->td_pri_class = class; 2006 } 2007 2008 /* 2009 * Return some of the child's priority and interactivity to the parent. 2010 */ 2011 void 2012 sched_exit(struct proc *p, struct thread *child) 2013 { 2014 struct thread *td; 2015 2016 CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d", 2017 child, child->td_name, child->td_priority); 2018 2019 PROC_LOCK_ASSERT(p, MA_OWNED); 2020 td = FIRST_THREAD_IN_PROC(p); 2021 sched_exit_thread(td, child); 2022 } 2023 2024 /* 2025 * Penalize another thread for the time spent on this one. This helps to 2026 * worsen the priority and interactivity of processes which schedule batch 2027 * jobs such as make. This has little effect on the make process itself but 2028 * causes new processes spawned by it to receive worse scores immediately. 2029 */ 2030 void 2031 sched_exit_thread(struct thread *td, struct thread *child) 2032 { 2033 2034 CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d", 2035 child, child->td_name, child->td_priority); 2036 2037 /* 2038 * Give the child's runtime to the parent without returning the 2039 * sleep time as a penalty to the parent. This causes shells that 2040 * launch expensive things to mark their children as expensive. 2041 */ 2042 thread_lock(td); 2043 td->td_sched->ts_runtime += child->td_sched->ts_runtime; 2044 sched_interact_update(td); 2045 sched_priority(td); 2046 thread_unlock(td); 2047 } 2048 2049 void 2050 sched_preempt(struct thread *td) 2051 { 2052 struct tdq *tdq; 2053 2054 thread_lock(td); 2055 tdq = TDQ_SELF(); 2056 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2057 tdq->tdq_ipipending = 0; 2058 if (td->td_priority > tdq->tdq_lowpri) { 2059 int flags; 2060 2061 flags = SW_INVOL | SW_PREEMPT; 2062 if (td->td_critnest > 1) 2063 td->td_owepreempt = 1; 2064 else if (TD_IS_IDLETHREAD(td)) 2065 mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL); 2066 else 2067 mi_switch(flags | SWT_REMOTEPREEMPT, NULL); 2068 } 2069 thread_unlock(td); 2070 } 2071 2072 /* 2073 * Fix priorities on return to user-space. Priorities may be elevated due 2074 * to static priorities in msleep() or similar. 2075 */ 2076 void 2077 sched_userret(struct thread *td) 2078 { 2079 /* 2080 * XXX we cheat slightly on the locking here to avoid locking in 2081 * the usual case. Setting td_priority here is essentially an 2082 * incomplete workaround for not setting it properly elsewhere. 2083 * Now that some interrupt handlers are threads, not setting it 2084 * properly elsewhere can clobber it in the window between setting 2085 * it here and returning to user mode, so don't waste time setting 2086 * it perfectly here. 2087 */ 2088 KASSERT((td->td_flags & TDF_BORROWING) == 0, 2089 ("thread with borrowed priority returning to userland")); 2090 if (td->td_priority != td->td_user_pri) { 2091 thread_lock(td); 2092 td->td_priority = td->td_user_pri; 2093 td->td_base_pri = td->td_user_pri; 2094 tdq_setlowpri(TDQ_SELF(), td); 2095 thread_unlock(td); 2096 } 2097 } 2098 2099 /* 2100 * Handle a stathz tick. This is really only relevant for timeshare 2101 * threads. 2102 */ 2103 void 2104 sched_clock(struct thread *td) 2105 { 2106 struct tdq *tdq; 2107 struct td_sched *ts; 2108 2109 THREAD_LOCK_ASSERT(td, MA_OWNED); 2110 tdq = TDQ_SELF(); 2111 #ifdef SMP 2112 /* 2113 * We run the long term load balancer infrequently on the first cpu. 2114 */ 2115 if (balance_tdq == tdq) { 2116 if (balance_ticks && --balance_ticks == 0) 2117 sched_balance(); 2118 } 2119 #endif 2120 /* 2121 * Save the old switch count so we have a record of the last ticks 2122 * activity. Initialize the new switch count based on our load. 2123 * If there is some activity seed it to reflect that. 2124 */ 2125 tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt; 2126 tdq->tdq_switchcnt = tdq->tdq_load; 2127 /* 2128 * Advance the insert index once for each tick to ensure that all 2129 * threads get a chance to run. 2130 */ 2131 if (tdq->tdq_idx == tdq->tdq_ridx) { 2132 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; 2133 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) 2134 tdq->tdq_ridx = tdq->tdq_idx; 2135 } 2136 ts = td->td_sched; 2137 if (td->td_pri_class & PRI_FIFO_BIT) 2138 return; 2139 if (td->td_pri_class == PRI_TIMESHARE) { 2140 /* 2141 * We used a tick; charge it to the thread so 2142 * that we can compute our interactivity. 2143 */ 2144 td->td_sched->ts_runtime += tickincr; 2145 sched_interact_update(td); 2146 sched_priority(td); 2147 } 2148 /* 2149 * We used up one time slice. 2150 */ 2151 if (--ts->ts_slice > 0) 2152 return; 2153 /* 2154 * We're out of time, force a requeue at userret(). 2155 */ 2156 ts->ts_slice = sched_slice; 2157 td->td_flags |= TDF_NEEDRESCHED; 2158 } 2159 2160 /* 2161 * Called once per hz tick. Used for cpu utilization information. This 2162 * is easier than trying to scale based on stathz. 2163 */ 2164 void 2165 sched_tick(void) 2166 { 2167 struct td_sched *ts; 2168 2169 ts = curthread->td_sched; 2170 /* 2171 * Ticks is updated asynchronously on a single cpu. Check here to 2172 * avoid incrementing ts_ticks multiple times in a single tick. 2173 */ 2174 if (ts->ts_ltick == ticks) 2175 return; 2176 /* Adjust ticks for pctcpu */ 2177 ts->ts_ticks += 1 << SCHED_TICK_SHIFT; 2178 ts->ts_ltick = ticks; 2179 /* 2180 * Update if we've exceeded our desired tick threshhold by over one 2181 * second. 2182 */ 2183 if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick) 2184 sched_pctcpu_update(ts); 2185 } 2186 2187 /* 2188 * Return whether the current CPU has runnable tasks. Used for in-kernel 2189 * cooperative idle threads. 2190 */ 2191 int 2192 sched_runnable(void) 2193 { 2194 struct tdq *tdq; 2195 int load; 2196 2197 load = 1; 2198 2199 tdq = TDQ_SELF(); 2200 if ((curthread->td_flags & TDF_IDLETD) != 0) { 2201 if (tdq->tdq_load > 0) 2202 goto out; 2203 } else 2204 if (tdq->tdq_load - 1 > 0) 2205 goto out; 2206 load = 0; 2207 out: 2208 return (load); 2209 } 2210 2211 /* 2212 * Choose the highest priority thread to run. The thread is removed from 2213 * the run-queue while running however the load remains. For SMP we set 2214 * the tdq in the global idle bitmask if it idles here. 2215 */ 2216 struct thread * 2217 sched_choose(void) 2218 { 2219 struct thread *td; 2220 struct tdq *tdq; 2221 2222 tdq = TDQ_SELF(); 2223 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2224 td = tdq_choose(tdq); 2225 if (td) { 2226 td->td_sched->ts_ltick = ticks; 2227 tdq_runq_rem(tdq, td); 2228 tdq->tdq_lowpri = td->td_priority; 2229 return (td); 2230 } 2231 tdq->tdq_lowpri = PRI_MAX_IDLE; 2232 return (PCPU_GET(idlethread)); 2233 } 2234 2235 /* 2236 * Set owepreempt if necessary. Preemption never happens directly in ULE, 2237 * we always request it once we exit a critical section. 2238 */ 2239 static inline void 2240 sched_setpreempt(struct thread *td) 2241 { 2242 struct thread *ctd; 2243 int cpri; 2244 int pri; 2245 2246 THREAD_LOCK_ASSERT(curthread, MA_OWNED); 2247 2248 ctd = curthread; 2249 pri = td->td_priority; 2250 cpri = ctd->td_priority; 2251 if (pri < cpri) 2252 ctd->td_flags |= TDF_NEEDRESCHED; 2253 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) 2254 return; 2255 if (!sched_shouldpreempt(pri, cpri, 0)) 2256 return; 2257 ctd->td_owepreempt = 1; 2258 } 2259 2260 /* 2261 * Add a thread to a thread queue. Select the appropriate runq and add the 2262 * thread to it. This is the internal function called when the tdq is 2263 * predetermined. 2264 */ 2265 void 2266 tdq_add(struct tdq *tdq, struct thread *td, int flags) 2267 { 2268 2269 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2270 KASSERT((td->td_inhibitors == 0), 2271 ("sched_add: trying to run inhibited thread")); 2272 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 2273 ("sched_add: bad thread state")); 2274 KASSERT(td->td_flags & TDF_INMEM, 2275 ("sched_add: thread swapped out")); 2276 2277 if (td->td_priority < tdq->tdq_lowpri) 2278 tdq->tdq_lowpri = td->td_priority; 2279 tdq_runq_add(tdq, td, flags); 2280 tdq_load_add(tdq, td); 2281 } 2282 2283 /* 2284 * Select the target thread queue and add a thread to it. Request 2285 * preemption or IPI a remote processor if required. 2286 */ 2287 void 2288 sched_add(struct thread *td, int flags) 2289 { 2290 struct tdq *tdq; 2291 #ifdef SMP 2292 int cpu; 2293 #endif 2294 CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)", 2295 td, td->td_name, td->td_priority, curthread, 2296 curthread->td_name); 2297 THREAD_LOCK_ASSERT(td, MA_OWNED); 2298 /* 2299 * Recalculate the priority before we select the target cpu or 2300 * run-queue. 2301 */ 2302 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 2303 sched_priority(td); 2304 #ifdef SMP 2305 /* 2306 * Pick the destination cpu and if it isn't ours transfer to the 2307 * target cpu. 2308 */ 2309 cpu = sched_pickcpu(td, flags); 2310 tdq = sched_setcpu(td, cpu, flags); 2311 tdq_add(tdq, td, flags); 2312 if (cpu != PCPU_GET(cpuid)) { 2313 tdq_notify(tdq, td); 2314 return; 2315 } 2316 #else 2317 tdq = TDQ_SELF(); 2318 TDQ_LOCK(tdq); 2319 /* 2320 * Now that the thread is moving to the run-queue, set the lock 2321 * to the scheduler's lock. 2322 */ 2323 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 2324 tdq_add(tdq, td, flags); 2325 #endif 2326 if (!(flags & SRQ_YIELDING)) 2327 sched_setpreempt(td); 2328 } 2329 2330 /* 2331 * Remove a thread from a run-queue without running it. This is used 2332 * when we're stealing a thread from a remote queue. Otherwise all threads 2333 * exit by calling sched_exit_thread() and sched_throw() themselves. 2334 */ 2335 void 2336 sched_rem(struct thread *td) 2337 { 2338 struct tdq *tdq; 2339 2340 CTR5(KTR_SCHED, "sched_rem: %p(%s) prio %d by %p(%s)", 2341 td, td->td_name, td->td_priority, curthread, 2342 curthread->td_name); 2343 tdq = TDQ_CPU(td->td_sched->ts_cpu); 2344 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2345 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2346 KASSERT(TD_ON_RUNQ(td), 2347 ("sched_rem: thread not on run queue")); 2348 tdq_runq_rem(tdq, td); 2349 tdq_load_rem(tdq, td); 2350 TD_SET_CAN_RUN(td); 2351 if (td->td_priority == tdq->tdq_lowpri) 2352 tdq_setlowpri(tdq, NULL); 2353 } 2354 2355 /* 2356 * Fetch cpu utilization information. Updates on demand. 2357 */ 2358 fixpt_t 2359 sched_pctcpu(struct thread *td) 2360 { 2361 fixpt_t pctcpu; 2362 struct td_sched *ts; 2363 2364 pctcpu = 0; 2365 ts = td->td_sched; 2366 if (ts == NULL) 2367 return (0); 2368 2369 thread_lock(td); 2370 if (ts->ts_ticks) { 2371 int rtick; 2372 2373 sched_pctcpu_update(ts); 2374 /* How many rtick per second ? */ 2375 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); 2376 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; 2377 } 2378 thread_unlock(td); 2379 2380 return (pctcpu); 2381 } 2382 2383 /* 2384 * Enforce affinity settings for a thread. Called after adjustments to 2385 * cpumask. 2386 */ 2387 void 2388 sched_affinity(struct thread *td) 2389 { 2390 #ifdef SMP 2391 struct td_sched *ts; 2392 int cpu; 2393 2394 THREAD_LOCK_ASSERT(td, MA_OWNED); 2395 ts = td->td_sched; 2396 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) 2397 return; 2398 if (!TD_IS_RUNNING(td)) 2399 return; 2400 td->td_flags |= TDF_NEEDRESCHED; 2401 if (!THREAD_CAN_MIGRATE(td)) 2402 return; 2403 /* 2404 * Assign the new cpu and force a switch before returning to 2405 * userspace. If the target thread is not running locally send 2406 * an ipi to force the issue. 2407 */ 2408 cpu = ts->ts_cpu; 2409 ts->ts_cpu = sched_pickcpu(td, 0); 2410 if (cpu != PCPU_GET(cpuid)) 2411 ipi_selected(1 << cpu, IPI_PREEMPT); 2412 #endif 2413 } 2414 2415 /* 2416 * Bind a thread to a target cpu. 2417 */ 2418 void 2419 sched_bind(struct thread *td, int cpu) 2420 { 2421 struct td_sched *ts; 2422 2423 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 2424 ts = td->td_sched; 2425 if (ts->ts_flags & TSF_BOUND) 2426 sched_unbind(td); 2427 ts->ts_flags |= TSF_BOUND; 2428 sched_pin(); 2429 if (PCPU_GET(cpuid) == cpu) 2430 return; 2431 ts->ts_cpu = cpu; 2432 /* When we return from mi_switch we'll be on the correct cpu. */ 2433 mi_switch(SW_VOL, NULL); 2434 } 2435 2436 /* 2437 * Release a bound thread. 2438 */ 2439 void 2440 sched_unbind(struct thread *td) 2441 { 2442 struct td_sched *ts; 2443 2444 THREAD_LOCK_ASSERT(td, MA_OWNED); 2445 ts = td->td_sched; 2446 if ((ts->ts_flags & TSF_BOUND) == 0) 2447 return; 2448 ts->ts_flags &= ~TSF_BOUND; 2449 sched_unpin(); 2450 } 2451 2452 int 2453 sched_is_bound(struct thread *td) 2454 { 2455 THREAD_LOCK_ASSERT(td, MA_OWNED); 2456 return (td->td_sched->ts_flags & TSF_BOUND); 2457 } 2458 2459 /* 2460 * Basic yield call. 2461 */ 2462 void 2463 sched_relinquish(struct thread *td) 2464 { 2465 thread_lock(td); 2466 mi_switch(SW_VOL | SWT_RELINQUISH, NULL); 2467 thread_unlock(td); 2468 } 2469 2470 /* 2471 * Return the total system load. 2472 */ 2473 int 2474 sched_load(void) 2475 { 2476 #ifdef SMP 2477 int total; 2478 int i; 2479 2480 total = 0; 2481 for (i = 0; i <= mp_maxid; i++) 2482 total += TDQ_CPU(i)->tdq_sysload; 2483 return (total); 2484 #else 2485 return (TDQ_SELF()->tdq_sysload); 2486 #endif 2487 } 2488 2489 int 2490 sched_sizeof_proc(void) 2491 { 2492 return (sizeof(struct proc)); 2493 } 2494 2495 int 2496 sched_sizeof_thread(void) 2497 { 2498 return (sizeof(struct thread) + sizeof(struct td_sched)); 2499 } 2500 2501 /* 2502 * The actual idle process. 2503 */ 2504 void 2505 sched_idletd(void *dummy) 2506 { 2507 struct thread *td; 2508 struct tdq *tdq; 2509 int switchcnt; 2510 int i; 2511 2512 td = curthread; 2513 tdq = TDQ_SELF(); 2514 mtx_assert(&Giant, MA_NOTOWNED); 2515 /* ULE relies on preemption for idle interruption. */ 2516 for (;;) { 2517 tdq->tdq_idlestate = TDQ_RUNNING; 2518 #ifdef SMP 2519 if (tdq_idled(tdq) == 0) 2520 continue; 2521 #endif 2522 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2523 /* 2524 * If we're switching very frequently, spin while checking 2525 * for load rather than entering a low power state that 2526 * requires an IPI. 2527 */ 2528 if (switchcnt > sched_idlespinthresh) { 2529 for (i = 0; i < sched_idlespins; i++) { 2530 if (tdq->tdq_load) 2531 break; 2532 cpu_spinwait(); 2533 } 2534 } 2535 /* 2536 * We must set our state to IDLE before checking 2537 * tdq_load for the last time to avoid a race with 2538 * tdq_notify(). 2539 */ 2540 if (tdq->tdq_load == 0) { 2541 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2542 tdq->tdq_idlestate = TDQ_IDLE; 2543 if (tdq->tdq_load == 0) 2544 cpu_idle(switchcnt > 1); 2545 } 2546 if (tdq->tdq_load) { 2547 thread_lock(td); 2548 mi_switch(SW_VOL | SWT_IDLE, NULL); 2549 thread_unlock(td); 2550 } 2551 } 2552 } 2553 2554 /* 2555 * A CPU is entering for the first time or a thread is exiting. 2556 */ 2557 void 2558 sched_throw(struct thread *td) 2559 { 2560 struct thread *newtd; 2561 struct tdq *tdq; 2562 2563 tdq = TDQ_SELF(); 2564 if (td == NULL) { 2565 /* Correct spinlock nesting and acquire the correct lock. */ 2566 TDQ_LOCK(tdq); 2567 spinlock_exit(); 2568 } else { 2569 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2570 tdq_load_rem(tdq, td); 2571 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 2572 } 2573 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 2574 newtd = choosethread(); 2575 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 2576 PCPU_SET(switchtime, cpu_ticks()); 2577 PCPU_SET(switchticks, ticks); 2578 cpu_throw(td, newtd); /* doesn't return */ 2579 } 2580 2581 /* 2582 * This is called from fork_exit(). Just acquire the correct locks and 2583 * let fork do the rest of the work. 2584 */ 2585 void 2586 sched_fork_exit(struct thread *td) 2587 { 2588 struct td_sched *ts; 2589 struct tdq *tdq; 2590 int cpuid; 2591 2592 /* 2593 * Finish setting up thread glue so that it begins execution in a 2594 * non-nested critical section with the scheduler lock held. 2595 */ 2596 cpuid = PCPU_GET(cpuid); 2597 tdq = TDQ_CPU(cpuid); 2598 ts = td->td_sched; 2599 if (TD_IS_IDLETHREAD(td)) 2600 td->td_lock = TDQ_LOCKPTR(tdq); 2601 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2602 td->td_oncpu = cpuid; 2603 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 2604 lock_profile_obtain_lock_success( 2605 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 2606 } 2607 2608 #ifdef SMP 2609 2610 /* 2611 * Build the CPU topology dump string. Is recursively called to collect 2612 * the topology tree. 2613 */ 2614 static int 2615 sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg, 2616 int indent) 2617 { 2618 int i, first; 2619 2620 sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent, 2621 "", indent, cg->cg_level); 2622 sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"0x%x\">", indent, "", 2623 cg->cg_count, cg->cg_mask); 2624 first = TRUE; 2625 for (i = 0; i < MAXCPU; i++) { 2626 if ((cg->cg_mask & (1 << i)) != 0) { 2627 if (!first) 2628 sbuf_printf(sb, ", "); 2629 else 2630 first = FALSE; 2631 sbuf_printf(sb, "%d", i); 2632 } 2633 } 2634 sbuf_printf(sb, "</cpu>\n"); 2635 2636 sbuf_printf(sb, "%*s <flags>", indent, ""); 2637 if (cg->cg_flags != 0) { 2638 if ((cg->cg_flags & CG_FLAG_HTT) != 0) 2639 sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>\n"); 2640 if ((cg->cg_flags & CG_FLAG_THREAD) != 0) 2641 sbuf_printf(sb, "<flag name=\"THREAD\">SMT group</flag>\n"); 2642 } 2643 sbuf_printf(sb, "</flags>\n"); 2644 2645 if (cg->cg_children > 0) { 2646 sbuf_printf(sb, "%*s <children>\n", indent, ""); 2647 for (i = 0; i < cg->cg_children; i++) 2648 sysctl_kern_sched_topology_spec_internal(sb, 2649 &cg->cg_child[i], indent+2); 2650 sbuf_printf(sb, "%*s </children>\n", indent, ""); 2651 } 2652 sbuf_printf(sb, "%*s</group>\n", indent, ""); 2653 return (0); 2654 } 2655 2656 /* 2657 * Sysctl handler for retrieving topology dump. It's a wrapper for 2658 * the recursive sysctl_kern_smp_topology_spec_internal(). 2659 */ 2660 static int 2661 sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS) 2662 { 2663 struct sbuf *topo; 2664 int err; 2665 2666 KASSERT(cpu_top != NULL, ("cpu_top isn't initialized")); 2667 2668 topo = sbuf_new(NULL, NULL, 500, SBUF_AUTOEXTEND); 2669 if (topo == NULL) 2670 return (ENOMEM); 2671 2672 sbuf_printf(topo, "<groups>\n"); 2673 err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1); 2674 sbuf_printf(topo, "</groups>\n"); 2675 2676 if (err == 0) { 2677 sbuf_finish(topo); 2678 err = SYSCTL_OUT(req, sbuf_data(topo), sbuf_len(topo)); 2679 } 2680 sbuf_delete(topo); 2681 return (err); 2682 } 2683 #endif 2684 2685 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); 2686 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0, 2687 "Scheduler name"); 2688 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 2689 "Slice size for timeshare threads"); 2690 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, 2691 "Interactivity score threshold"); 2692 SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh, 2693 0,"Min priority for preemption, lower priorities have greater precedence"); 2694 SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 2695 0,"Controls whether static kernel priorities are assigned to sleeping threads."); 2696 SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 2697 0,"Number of times idle will spin waiting for new work."); 2698 SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW, &sched_idlespinthresh, 2699 0,"Threshold before we will permit idle spinning."); 2700 #ifdef SMP 2701 SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0, 2702 "Number of hz ticks to keep thread affinity for"); 2703 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, 2704 "Enables the long-term load balancer"); 2705 SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW, 2706 &balance_interval, 0, 2707 "Average frequency in stathz ticks to run the long-term balancer"); 2708 SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0, 2709 "Steals work from another hyper-threaded core on idle"); 2710 SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0, 2711 "Attempts to steal work from other cores before idling"); 2712 SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0, 2713 "Minimum load on remote cpu before we'll steal"); 2714 2715 /* Retrieve SMP topology */ 2716 SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING | 2717 CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A", 2718 "XML dump of detected CPU topology"); 2719 #endif 2720 2721 /* ps compat. All cpu percentages from ULE are weighted. */ 2722 static int ccpu = 0; 2723 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 2724