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 66 #ifdef HWPMC_HOOKS 67 #include <sys/pmckern.h> 68 #endif 69 70 #ifdef KDTRACE_HOOKS 71 #include <sys/dtrace_bsd.h> 72 int dtrace_vtime_active; 73 dtrace_vtime_switch_func_t dtrace_vtime_switch_func; 74 #endif 75 76 #include <machine/cpu.h> 77 #include <machine/smp.h> 78 79 #if defined(__powerpc__) && defined(E500) 80 #error "This architecture is not currently compatible with ULE" 81 #endif 82 83 #define KTR_ULE 0 84 85 #define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX))) 86 #define TDQ_NAME_LEN (sizeof("sched lock ") + sizeof(__XSTRING(MAXCPU))) 87 #define TDQ_LOADNAME_LEN (sizeof("CPU ") + sizeof(__XSTRING(MAXCPU)) - 1 + sizeof(" load")) 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_incrtick; /* Last tick that we incremented on */ 103 int ts_ftick; /* First tick that we were running on */ 104 int ts_ticks; /* Tick count */ 105 #ifdef KTR 106 char ts_name[TS_NAME_LEN]; 107 #endif 108 }; 109 /* flags kept in ts_flags */ 110 #define TSF_BOUND 0x0001 /* Thread can not migrate. */ 111 #define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */ 112 113 static struct td_sched td_sched0; 114 115 #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0) 116 #define THREAD_CAN_SCHED(td, cpu) \ 117 CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask) 118 119 /* 120 * Priority ranges used for interactive and non-interactive timeshare 121 * threads. The timeshare priorities are split up into four ranges. 122 * The first range handles interactive threads. The last three ranges 123 * (NHALF, x, and NHALF) handle non-interactive threads with the outer 124 * ranges supporting nice values. 125 */ 126 #define PRI_TIMESHARE_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1) 127 #define PRI_INTERACT_RANGE ((PRI_TIMESHARE_RANGE - SCHED_PRI_NRESV) / 2) 128 #define PRI_BATCH_RANGE (PRI_TIMESHARE_RANGE - PRI_INTERACT_RANGE) 129 130 #define PRI_MIN_INTERACT PRI_MIN_TIMESHARE 131 #define PRI_MAX_INTERACT (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE - 1) 132 #define PRI_MIN_BATCH (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE) 133 #define PRI_MAX_BATCH PRI_MAX_TIMESHARE 134 135 /* 136 * Cpu percentage computation macros and defines. 137 * 138 * SCHED_TICK_SECS: Number of seconds to average the cpu usage across. 139 * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across. 140 * SCHED_TICK_MAX: Maximum number of ticks before scaling back. 141 * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results. 142 * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count. 143 * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks. 144 */ 145 #define SCHED_TICK_SECS 10 146 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS) 147 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz) 148 #define SCHED_TICK_SHIFT 10 149 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT) 150 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz)) 151 152 /* 153 * These macros determine priorities for non-interactive threads. They are 154 * assigned a priority based on their recent cpu utilization as expressed 155 * by the ratio of ticks to the tick total. NHALF priorities at the start 156 * and end of the MIN to MAX timeshare range are only reachable with negative 157 * or positive nice respectively. 158 * 159 * PRI_RANGE: Priority range for utilization dependent priorities. 160 * PRI_NRESV: Number of nice values. 161 * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total. 162 * PRI_NICE: Determines the part of the priority inherited from nice. 163 */ 164 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN) 165 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) 166 #define SCHED_PRI_MIN (PRI_MIN_BATCH + SCHED_PRI_NHALF) 167 #define SCHED_PRI_MAX (PRI_MAX_BATCH - SCHED_PRI_NHALF) 168 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN + 1) 169 #define SCHED_PRI_TICKS(ts) \ 170 (SCHED_TICK_HZ((ts)) / \ 171 (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE)) 172 #define SCHED_PRI_NICE(nice) (nice) 173 174 /* 175 * These determine the interactivity of a process. Interactivity differs from 176 * cpu utilization in that it expresses the voluntary time slept vs time ran 177 * while cpu utilization includes all time not running. This more accurately 178 * models the intent of the thread. 179 * 180 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 181 * before throttling back. 182 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. 183 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 184 * INTERACT_THRESH: Threshold for placement on the current runq. 185 */ 186 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT) 187 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT) 188 #define SCHED_INTERACT_MAX (100) 189 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 190 #define SCHED_INTERACT_THRESH (30) 191 192 /* 193 * tickincr: Converts a stathz tick into a hz domain scaled by 194 * the shift factor. Without the shift the error rate 195 * due to rounding would be unacceptably high. 196 * realstathz: stathz is sometimes 0 and run off of hz. 197 * sched_slice: Runtime of each thread before rescheduling. 198 * preempt_thresh: Priority threshold for preemption and remote IPIs. 199 */ 200 static int sched_interact = SCHED_INTERACT_THRESH; 201 static int realstathz; 202 static int tickincr; 203 static int sched_slice = 1; 204 #ifdef PREEMPTION 205 #ifdef FULL_PREEMPTION 206 static int preempt_thresh = PRI_MAX_IDLE; 207 #else 208 static int preempt_thresh = PRI_MIN_KERN; 209 #endif 210 #else 211 static int preempt_thresh = 0; 212 #endif 213 static int static_boost = PRI_MIN_BATCH; 214 static int sched_idlespins = 10000; 215 static int sched_idlespinthresh = 16; 216 217 /* 218 * tdq - per processor runqs and statistics. All fields are protected by the 219 * tdq_lock. The load and lowpri may be accessed without to avoid excess 220 * locking in sched_pickcpu(); 221 */ 222 struct tdq { 223 /* Ordered to improve efficiency of cpu_search() and switch(). */ 224 struct mtx tdq_lock; /* run queue lock. */ 225 struct cpu_group *tdq_cg; /* Pointer to cpu topology. */ 226 volatile int tdq_load; /* Aggregate load. */ 227 volatile int tdq_cpu_idle; /* cpu_idle() is active. */ 228 int tdq_sysload; /* For loadavg, !ITHD load. */ 229 int tdq_transferable; /* Transferable thread count. */ 230 short tdq_switchcnt; /* Switches this tick. */ 231 short tdq_oldswitchcnt; /* Switches last tick. */ 232 u_char tdq_lowpri; /* Lowest priority thread. */ 233 u_char tdq_ipipending; /* IPI pending. */ 234 u_char tdq_idx; /* Current insert index. */ 235 u_char tdq_ridx; /* Current removal index. */ 236 struct runq tdq_realtime; /* real-time run queue. */ 237 struct runq tdq_timeshare; /* timeshare run queue. */ 238 struct runq tdq_idle; /* Queue of IDLE threads. */ 239 char tdq_name[TDQ_NAME_LEN]; 240 #ifdef KTR 241 char tdq_loadname[TDQ_LOADNAME_LEN]; 242 #endif 243 } __aligned(64); 244 245 /* Idle thread states and config. */ 246 #define TDQ_RUNNING 1 247 #define TDQ_IDLE 2 248 249 #ifdef SMP 250 struct cpu_group *cpu_top; /* CPU topology */ 251 252 #define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000)) 253 #define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity)) 254 255 /* 256 * Run-time tunables. 257 */ 258 static int rebalance = 1; 259 static int balance_interval = 128; /* Default set in sched_initticks(). */ 260 static int affinity; 261 static int steal_htt = 1; 262 static int steal_idle = 1; 263 static int steal_thresh = 2; 264 265 /* 266 * One thread queue per processor. 267 */ 268 static struct tdq tdq_cpu[MAXCPU]; 269 static struct tdq *balance_tdq; 270 static int balance_ticks; 271 272 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)]) 273 #define TDQ_CPU(x) (&tdq_cpu[(x)]) 274 #define TDQ_ID(x) ((int)((x) - tdq_cpu)) 275 #else /* !SMP */ 276 static struct tdq tdq_cpu; 277 278 #define TDQ_ID(x) (0) 279 #define TDQ_SELF() (&tdq_cpu) 280 #define TDQ_CPU(x) (&tdq_cpu) 281 #endif 282 283 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type)) 284 #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t))) 285 #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f)) 286 #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t))) 287 #define TDQ_LOCKPTR(t) (&(t)->tdq_lock) 288 289 static void sched_priority(struct thread *); 290 static void sched_thread_priority(struct thread *, u_char); 291 static int sched_interact_score(struct thread *); 292 static void sched_interact_update(struct thread *); 293 static void sched_interact_fork(struct thread *); 294 static void sched_pctcpu_update(struct td_sched *); 295 296 /* Operations on per processor queues */ 297 static struct thread *tdq_choose(struct tdq *); 298 static void tdq_setup(struct tdq *); 299 static void tdq_load_add(struct tdq *, struct thread *); 300 static void tdq_load_rem(struct tdq *, struct thread *); 301 static __inline void tdq_runq_add(struct tdq *, struct thread *, int); 302 static __inline void tdq_runq_rem(struct tdq *, struct thread *); 303 static inline int sched_shouldpreempt(int, int, int); 304 void tdq_print(int cpu); 305 static void runq_print(struct runq *rq); 306 static void tdq_add(struct tdq *, struct thread *, int); 307 #ifdef SMP 308 static int tdq_move(struct tdq *, struct tdq *); 309 static int tdq_idled(struct tdq *); 310 static void tdq_notify(struct tdq *, struct thread *); 311 static struct thread *tdq_steal(struct tdq *, int); 312 static struct thread *runq_steal(struct runq *, int); 313 static int sched_pickcpu(struct thread *, int); 314 static void sched_balance(void); 315 static int sched_balance_pair(struct tdq *, struct tdq *); 316 static inline struct tdq *sched_setcpu(struct thread *, int, int); 317 static inline void thread_unblock_switch(struct thread *, struct mtx *); 318 static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int); 319 static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS); 320 static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, 321 struct cpu_group *cg, int indent); 322 #endif 323 324 static void sched_setup(void *dummy); 325 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL); 326 327 static void sched_initticks(void *dummy); 328 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, 329 NULL); 330 331 /* 332 * Print the threads waiting on a run-queue. 333 */ 334 static void 335 runq_print(struct runq *rq) 336 { 337 struct rqhead *rqh; 338 struct thread *td; 339 int pri; 340 int j; 341 int i; 342 343 for (i = 0; i < RQB_LEN; i++) { 344 printf("\t\trunq bits %d 0x%zx\n", 345 i, rq->rq_status.rqb_bits[i]); 346 for (j = 0; j < RQB_BPW; j++) 347 if (rq->rq_status.rqb_bits[i] & (1ul << j)) { 348 pri = j + (i << RQB_L2BPW); 349 rqh = &rq->rq_queues[pri]; 350 TAILQ_FOREACH(td, rqh, td_runq) { 351 printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n", 352 td, td->td_name, td->td_priority, 353 td->td_rqindex, pri); 354 } 355 } 356 } 357 } 358 359 /* 360 * Print the status of a per-cpu thread queue. Should be a ddb show cmd. 361 */ 362 void 363 tdq_print(int cpu) 364 { 365 struct tdq *tdq; 366 367 tdq = TDQ_CPU(cpu); 368 369 printf("tdq %d:\n", TDQ_ID(tdq)); 370 printf("\tlock %p\n", TDQ_LOCKPTR(tdq)); 371 printf("\tLock name: %s\n", tdq->tdq_name); 372 printf("\tload: %d\n", tdq->tdq_load); 373 printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt); 374 printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt); 375 printf("\ttimeshare idx: %d\n", tdq->tdq_idx); 376 printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx); 377 printf("\tload transferable: %d\n", tdq->tdq_transferable); 378 printf("\tlowest priority: %d\n", tdq->tdq_lowpri); 379 printf("\trealtime runq:\n"); 380 runq_print(&tdq->tdq_realtime); 381 printf("\ttimeshare runq:\n"); 382 runq_print(&tdq->tdq_timeshare); 383 printf("\tidle runq:\n"); 384 runq_print(&tdq->tdq_idle); 385 } 386 387 static inline int 388 sched_shouldpreempt(int pri, int cpri, int remote) 389 { 390 /* 391 * If the new priority is not better than the current priority there is 392 * nothing to do. 393 */ 394 if (pri >= cpri) 395 return (0); 396 /* 397 * Always preempt idle. 398 */ 399 if (cpri >= PRI_MIN_IDLE) 400 return (1); 401 /* 402 * If preemption is disabled don't preempt others. 403 */ 404 if (preempt_thresh == 0) 405 return (0); 406 /* 407 * Preempt if we exceed the threshold. 408 */ 409 if (pri <= preempt_thresh) 410 return (1); 411 /* 412 * If we're interactive or better and there is non-interactive 413 * or worse running preempt only remote processors. 414 */ 415 if (remote && pri <= PRI_MAX_INTERACT && cpri > PRI_MAX_INTERACT) 416 return (1); 417 return (0); 418 } 419 420 /* 421 * Add a thread to the actual run-queue. Keeps transferable counts up to 422 * date with what is actually on the run-queue. Selects the correct 423 * queue position for timeshare threads. 424 */ 425 static __inline void 426 tdq_runq_add(struct tdq *tdq, struct thread *td, int flags) 427 { 428 struct td_sched *ts; 429 u_char pri; 430 431 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 432 THREAD_LOCK_ASSERT(td, MA_OWNED); 433 434 pri = td->td_priority; 435 ts = td->td_sched; 436 TD_SET_RUNQ(td); 437 if (THREAD_CAN_MIGRATE(td)) { 438 tdq->tdq_transferable++; 439 ts->ts_flags |= TSF_XFERABLE; 440 } 441 if (pri < PRI_MIN_BATCH) { 442 ts->ts_runq = &tdq->tdq_realtime; 443 } else if (pri <= PRI_MAX_BATCH) { 444 ts->ts_runq = &tdq->tdq_timeshare; 445 KASSERT(pri <= PRI_MAX_BATCH && pri >= PRI_MIN_BATCH, 446 ("Invalid priority %d on timeshare runq", pri)); 447 /* 448 * This queue contains only priorities between MIN and MAX 449 * realtime. Use the whole queue to represent these values. 450 */ 451 if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) { 452 pri = RQ_NQS * (pri - PRI_MIN_BATCH) / PRI_BATCH_RANGE; 453 pri = (pri + tdq->tdq_idx) % RQ_NQS; 454 /* 455 * This effectively shortens the queue by one so we 456 * can have a one slot difference between idx and 457 * ridx while we wait for threads to drain. 458 */ 459 if (tdq->tdq_ridx != tdq->tdq_idx && 460 pri == tdq->tdq_ridx) 461 pri = (unsigned char)(pri - 1) % RQ_NQS; 462 } else 463 pri = tdq->tdq_ridx; 464 runq_add_pri(ts->ts_runq, td, pri, flags); 465 return; 466 } else 467 ts->ts_runq = &tdq->tdq_idle; 468 runq_add(ts->ts_runq, td, flags); 469 } 470 471 /* 472 * Remove a thread from a run-queue. This typically happens when a thread 473 * is selected to run. Running threads are not on the queue and the 474 * transferable count does not reflect them. 475 */ 476 static __inline void 477 tdq_runq_rem(struct tdq *tdq, struct thread *td) 478 { 479 struct td_sched *ts; 480 481 ts = td->td_sched; 482 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 483 KASSERT(ts->ts_runq != NULL, 484 ("tdq_runq_remove: thread %p null ts_runq", td)); 485 if (ts->ts_flags & TSF_XFERABLE) { 486 tdq->tdq_transferable--; 487 ts->ts_flags &= ~TSF_XFERABLE; 488 } 489 if (ts->ts_runq == &tdq->tdq_timeshare) { 490 if (tdq->tdq_idx != tdq->tdq_ridx) 491 runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx); 492 else 493 runq_remove_idx(ts->ts_runq, td, NULL); 494 } else 495 runq_remove(ts->ts_runq, td); 496 } 497 498 /* 499 * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load 500 * for this thread to the referenced thread queue. 501 */ 502 static void 503 tdq_load_add(struct tdq *tdq, struct thread *td) 504 { 505 506 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 507 THREAD_LOCK_ASSERT(td, MA_OWNED); 508 509 tdq->tdq_load++; 510 if ((td->td_flags & TDF_NOLOAD) == 0) 511 tdq->tdq_sysload++; 512 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load); 513 } 514 515 /* 516 * Remove the load from a thread that is transitioning to a sleep state or 517 * exiting. 518 */ 519 static void 520 tdq_load_rem(struct tdq *tdq, struct thread *td) 521 { 522 523 THREAD_LOCK_ASSERT(td, MA_OWNED); 524 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 525 KASSERT(tdq->tdq_load != 0, 526 ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq))); 527 528 tdq->tdq_load--; 529 if ((td->td_flags & TDF_NOLOAD) == 0) 530 tdq->tdq_sysload--; 531 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load); 532 } 533 534 /* 535 * Set lowpri to its exact value by searching the run-queue and 536 * evaluating curthread. curthread may be passed as an optimization. 537 */ 538 static void 539 tdq_setlowpri(struct tdq *tdq, struct thread *ctd) 540 { 541 struct thread *td; 542 543 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 544 if (ctd == NULL) 545 ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread; 546 td = tdq_choose(tdq); 547 if (td == NULL || td->td_priority > ctd->td_priority) 548 tdq->tdq_lowpri = ctd->td_priority; 549 else 550 tdq->tdq_lowpri = td->td_priority; 551 } 552 553 #ifdef SMP 554 struct cpu_search { 555 cpuset_t cs_mask; 556 u_int cs_load; 557 u_int cs_cpu; 558 int cs_limit; /* Min priority for low min load for high. */ 559 }; 560 561 #define CPU_SEARCH_LOWEST 0x1 562 #define CPU_SEARCH_HIGHEST 0x2 563 #define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST) 564 565 #define CPUSET_FOREACH(cpu, mask) \ 566 for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++) \ 567 if (CPU_ISSET(cpu, &mask)) 568 569 static __inline int cpu_search(struct cpu_group *cg, struct cpu_search *low, 570 struct cpu_search *high, const int match); 571 int cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low); 572 int cpu_search_highest(struct cpu_group *cg, struct cpu_search *high); 573 int cpu_search_both(struct cpu_group *cg, struct cpu_search *low, 574 struct cpu_search *high); 575 576 /* 577 * This routine compares according to the match argument and should be 578 * reduced in actual instantiations via constant propagation and dead code 579 * elimination. 580 */ 581 static __inline int 582 cpu_compare(int cpu, struct cpu_search *low, struct cpu_search *high, 583 const int match) 584 { 585 struct tdq *tdq; 586 587 tdq = TDQ_CPU(cpu); 588 if (match & CPU_SEARCH_LOWEST) 589 if (CPU_ISSET(cpu, &low->cs_mask) && 590 tdq->tdq_load < low->cs_load && 591 tdq->tdq_lowpri > low->cs_limit) { 592 low->cs_cpu = cpu; 593 low->cs_load = tdq->tdq_load; 594 } 595 if (match & CPU_SEARCH_HIGHEST) 596 if (CPU_ISSET(cpu, &high->cs_mask) && 597 tdq->tdq_load >= high->cs_limit && 598 tdq->tdq_load > high->cs_load && 599 tdq->tdq_transferable) { 600 high->cs_cpu = cpu; 601 high->cs_load = tdq->tdq_load; 602 } 603 return (tdq->tdq_load); 604 } 605 606 /* 607 * Search the tree of cpu_groups for the lowest or highest loaded cpu 608 * according to the match argument. This routine actually compares the 609 * load on all paths through the tree and finds the least loaded cpu on 610 * the least loaded path, which may differ from the least loaded cpu in 611 * the system. This balances work among caches and busses. 612 * 613 * This inline is instantiated in three forms below using constants for the 614 * match argument. It is reduced to the minimum set for each case. It is 615 * also recursive to the depth of the tree. 616 */ 617 static __inline int 618 cpu_search(struct cpu_group *cg, struct cpu_search *low, 619 struct cpu_search *high, const int match) 620 { 621 int total; 622 623 total = 0; 624 if (cg->cg_children) { 625 struct cpu_search lgroup; 626 struct cpu_search hgroup; 627 struct cpu_group *child; 628 u_int lload; 629 int hload; 630 int load; 631 int i; 632 633 lload = -1; 634 hload = -1; 635 for (i = 0; i < cg->cg_children; i++) { 636 child = &cg->cg_child[i]; 637 if (match & CPU_SEARCH_LOWEST) { 638 lgroup = *low; 639 lgroup.cs_load = -1; 640 } 641 if (match & CPU_SEARCH_HIGHEST) { 642 hgroup = *high; 643 lgroup.cs_load = 0; 644 } 645 switch (match) { 646 case CPU_SEARCH_LOWEST: 647 load = cpu_search_lowest(child, &lgroup); 648 break; 649 case CPU_SEARCH_HIGHEST: 650 load = cpu_search_highest(child, &hgroup); 651 break; 652 case CPU_SEARCH_BOTH: 653 load = cpu_search_both(child, &lgroup, &hgroup); 654 break; 655 } 656 total += load; 657 if (match & CPU_SEARCH_LOWEST) 658 if (load < lload || low->cs_cpu == -1) { 659 *low = lgroup; 660 lload = load; 661 } 662 if (match & CPU_SEARCH_HIGHEST) 663 if (load > hload || high->cs_cpu == -1) { 664 hload = load; 665 *high = hgroup; 666 } 667 } 668 } else { 669 int cpu; 670 671 CPUSET_FOREACH(cpu, cg->cg_mask) 672 total += cpu_compare(cpu, low, high, match); 673 } 674 return (total); 675 } 676 677 /* 678 * cpu_search instantiations must pass constants to maintain the inline 679 * optimization. 680 */ 681 int 682 cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low) 683 { 684 return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST); 685 } 686 687 int 688 cpu_search_highest(struct cpu_group *cg, struct cpu_search *high) 689 { 690 return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST); 691 } 692 693 int 694 cpu_search_both(struct cpu_group *cg, struct cpu_search *low, 695 struct cpu_search *high) 696 { 697 return cpu_search(cg, low, high, CPU_SEARCH_BOTH); 698 } 699 700 /* 701 * Find the cpu with the least load via the least loaded path that has a 702 * lowpri greater than pri pri. A pri of -1 indicates any priority is 703 * acceptable. 704 */ 705 static inline int 706 sched_lowest(struct cpu_group *cg, cpuset_t mask, int pri) 707 { 708 struct cpu_search low; 709 710 low.cs_cpu = -1; 711 low.cs_load = -1; 712 low.cs_mask = mask; 713 low.cs_limit = pri; 714 cpu_search_lowest(cg, &low); 715 return low.cs_cpu; 716 } 717 718 /* 719 * Find the cpu with the highest load via the highest loaded path. 720 */ 721 static inline int 722 sched_highest(struct cpu_group *cg, cpuset_t mask, int minload) 723 { 724 struct cpu_search high; 725 726 high.cs_cpu = -1; 727 high.cs_load = 0; 728 high.cs_mask = mask; 729 high.cs_limit = minload; 730 cpu_search_highest(cg, &high); 731 return high.cs_cpu; 732 } 733 734 /* 735 * Simultaneously find the highest and lowest loaded cpu reachable via 736 * cg. 737 */ 738 static inline void 739 sched_both(struct cpu_group *cg, cpuset_t mask, int *lowcpu, int *highcpu) 740 { 741 struct cpu_search high; 742 struct cpu_search low; 743 744 low.cs_cpu = -1; 745 low.cs_limit = -1; 746 low.cs_load = -1; 747 low.cs_mask = mask; 748 high.cs_load = 0; 749 high.cs_cpu = -1; 750 high.cs_limit = -1; 751 high.cs_mask = mask; 752 cpu_search_both(cg, &low, &high); 753 *lowcpu = low.cs_cpu; 754 *highcpu = high.cs_cpu; 755 return; 756 } 757 758 static void 759 sched_balance_group(struct cpu_group *cg) 760 { 761 cpuset_t mask; 762 int high; 763 int low; 764 int i; 765 766 CPU_FILL(&mask); 767 for (;;) { 768 sched_both(cg, mask, &low, &high); 769 if (low == high || low == -1 || high == -1) 770 break; 771 if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low))) 772 break; 773 /* 774 * If we failed to move any threads determine which cpu 775 * to kick out of the set and try again. 776 */ 777 if (TDQ_CPU(high)->tdq_transferable == 0) 778 CPU_CLR(high, &mask); 779 else 780 CPU_CLR(low, &mask); 781 } 782 783 for (i = 0; i < cg->cg_children; i++) 784 sched_balance_group(&cg->cg_child[i]); 785 } 786 787 static void 788 sched_balance(void) 789 { 790 struct tdq *tdq; 791 792 /* 793 * Select a random time between .5 * balance_interval and 794 * 1.5 * balance_interval. 795 */ 796 balance_ticks = max(balance_interval / 2, 1); 797 balance_ticks += random() % balance_interval; 798 if (smp_started == 0 || rebalance == 0) 799 return; 800 tdq = TDQ_SELF(); 801 TDQ_UNLOCK(tdq); 802 sched_balance_group(cpu_top); 803 TDQ_LOCK(tdq); 804 } 805 806 /* 807 * Lock two thread queues using their address to maintain lock order. 808 */ 809 static void 810 tdq_lock_pair(struct tdq *one, struct tdq *two) 811 { 812 if (one < two) { 813 TDQ_LOCK(one); 814 TDQ_LOCK_FLAGS(two, MTX_DUPOK); 815 } else { 816 TDQ_LOCK(two); 817 TDQ_LOCK_FLAGS(one, MTX_DUPOK); 818 } 819 } 820 821 /* 822 * Unlock two thread queues. Order is not important here. 823 */ 824 static void 825 tdq_unlock_pair(struct tdq *one, struct tdq *two) 826 { 827 TDQ_UNLOCK(one); 828 TDQ_UNLOCK(two); 829 } 830 831 /* 832 * Transfer load between two imbalanced thread queues. 833 */ 834 static int 835 sched_balance_pair(struct tdq *high, struct tdq *low) 836 { 837 int transferable; 838 int high_load; 839 int low_load; 840 int moved; 841 int move; 842 int cpu; 843 int diff; 844 int i; 845 846 tdq_lock_pair(high, low); 847 transferable = high->tdq_transferable; 848 high_load = high->tdq_load; 849 low_load = low->tdq_load; 850 moved = 0; 851 /* 852 * Determine what the imbalance is and then adjust that to how many 853 * threads we actually have to give up (transferable). 854 */ 855 if (transferable != 0) { 856 diff = high_load - low_load; 857 move = diff / 2; 858 if (diff & 0x1) 859 move++; 860 move = min(move, transferable); 861 for (i = 0; i < move; i++) 862 moved += tdq_move(high, low); 863 /* 864 * In case the target isn't the current cpu IPI it to force a 865 * reschedule with the new workload. 866 */ 867 cpu = TDQ_ID(low); 868 sched_pin(); 869 if (cpu != PCPU_GET(cpuid)) 870 ipi_cpu(cpu, IPI_PREEMPT); 871 sched_unpin(); 872 } 873 tdq_unlock_pair(high, low); 874 return (moved); 875 } 876 877 /* 878 * Move a thread from one thread queue to another. 879 */ 880 static int 881 tdq_move(struct tdq *from, struct tdq *to) 882 { 883 struct td_sched *ts; 884 struct thread *td; 885 struct tdq *tdq; 886 int cpu; 887 888 TDQ_LOCK_ASSERT(from, MA_OWNED); 889 TDQ_LOCK_ASSERT(to, MA_OWNED); 890 891 tdq = from; 892 cpu = TDQ_ID(to); 893 td = tdq_steal(tdq, cpu); 894 if (td == NULL) 895 return (0); 896 ts = td->td_sched; 897 /* 898 * Although the run queue is locked the thread may be blocked. Lock 899 * it to clear this and acquire the run-queue lock. 900 */ 901 thread_lock(td); 902 /* Drop recursive lock on from acquired via thread_lock(). */ 903 TDQ_UNLOCK(from); 904 sched_rem(td); 905 ts->ts_cpu = cpu; 906 td->td_lock = TDQ_LOCKPTR(to); 907 tdq_add(to, td, SRQ_YIELDING); 908 return (1); 909 } 910 911 /* 912 * This tdq has idled. Try to steal a thread from another cpu and switch 913 * to it. 914 */ 915 static int 916 tdq_idled(struct tdq *tdq) 917 { 918 struct cpu_group *cg; 919 struct tdq *steal; 920 cpuset_t mask; 921 int thresh; 922 int cpu; 923 924 if (smp_started == 0 || steal_idle == 0) 925 return (1); 926 CPU_FILL(&mask); 927 CPU_CLR(PCPU_GET(cpuid), &mask); 928 /* We don't want to be preempted while we're iterating. */ 929 spinlock_enter(); 930 for (cg = tdq->tdq_cg; cg != NULL; ) { 931 if ((cg->cg_flags & CG_FLAG_THREAD) == 0) 932 thresh = steal_thresh; 933 else 934 thresh = 1; 935 cpu = sched_highest(cg, mask, thresh); 936 if (cpu == -1) { 937 cg = cg->cg_parent; 938 continue; 939 } 940 steal = TDQ_CPU(cpu); 941 CPU_CLR(cpu, &mask); 942 tdq_lock_pair(tdq, steal); 943 if (steal->tdq_load < thresh || steal->tdq_transferable == 0) { 944 tdq_unlock_pair(tdq, steal); 945 continue; 946 } 947 /* 948 * If a thread was added while interrupts were disabled don't 949 * steal one here. If we fail to acquire one due to affinity 950 * restrictions loop again with this cpu removed from the 951 * set. 952 */ 953 if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) { 954 tdq_unlock_pair(tdq, steal); 955 continue; 956 } 957 spinlock_exit(); 958 TDQ_UNLOCK(steal); 959 mi_switch(SW_VOL | SWT_IDLE, NULL); 960 thread_unlock(curthread); 961 962 return (0); 963 } 964 spinlock_exit(); 965 return (1); 966 } 967 968 /* 969 * Notify a remote cpu of new work. Sends an IPI if criteria are met. 970 */ 971 static void 972 tdq_notify(struct tdq *tdq, struct thread *td) 973 { 974 struct thread *ctd; 975 int pri; 976 int cpu; 977 978 if (tdq->tdq_ipipending) 979 return; 980 cpu = td->td_sched->ts_cpu; 981 pri = td->td_priority; 982 ctd = pcpu_find(cpu)->pc_curthread; 983 if (!sched_shouldpreempt(pri, ctd->td_priority, 1)) 984 return; 985 if (TD_IS_IDLETHREAD(ctd)) { 986 /* 987 * If the MD code has an idle wakeup routine try that before 988 * falling back to IPI. 989 */ 990 if (!tdq->tdq_cpu_idle || cpu_idle_wakeup(cpu)) 991 return; 992 } 993 tdq->tdq_ipipending = 1; 994 ipi_cpu(cpu, IPI_PREEMPT); 995 } 996 997 /* 998 * Steals load from a timeshare queue. Honors the rotating queue head 999 * index. 1000 */ 1001 static struct thread * 1002 runq_steal_from(struct runq *rq, int cpu, u_char start) 1003 { 1004 struct rqbits *rqb; 1005 struct rqhead *rqh; 1006 struct thread *td; 1007 int first; 1008 int bit; 1009 int pri; 1010 int i; 1011 1012 rqb = &rq->rq_status; 1013 bit = start & (RQB_BPW -1); 1014 pri = 0; 1015 first = 0; 1016 again: 1017 for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) { 1018 if (rqb->rqb_bits[i] == 0) 1019 continue; 1020 if (bit != 0) { 1021 for (pri = bit; pri < RQB_BPW; pri++) 1022 if (rqb->rqb_bits[i] & (1ul << pri)) 1023 break; 1024 if (pri >= RQB_BPW) 1025 continue; 1026 } else 1027 pri = RQB_FFS(rqb->rqb_bits[i]); 1028 pri += (i << RQB_L2BPW); 1029 rqh = &rq->rq_queues[pri]; 1030 TAILQ_FOREACH(td, rqh, td_runq) { 1031 if (first && THREAD_CAN_MIGRATE(td) && 1032 THREAD_CAN_SCHED(td, cpu)) 1033 return (td); 1034 first = 1; 1035 } 1036 } 1037 if (start != 0) { 1038 start = 0; 1039 goto again; 1040 } 1041 1042 return (NULL); 1043 } 1044 1045 /* 1046 * Steals load from a standard linear queue. 1047 */ 1048 static struct thread * 1049 runq_steal(struct runq *rq, int cpu) 1050 { 1051 struct rqhead *rqh; 1052 struct rqbits *rqb; 1053 struct thread *td; 1054 int word; 1055 int bit; 1056 1057 rqb = &rq->rq_status; 1058 for (word = 0; word < RQB_LEN; word++) { 1059 if (rqb->rqb_bits[word] == 0) 1060 continue; 1061 for (bit = 0; bit < RQB_BPW; bit++) { 1062 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) 1063 continue; 1064 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; 1065 TAILQ_FOREACH(td, rqh, td_runq) 1066 if (THREAD_CAN_MIGRATE(td) && 1067 THREAD_CAN_SCHED(td, cpu)) 1068 return (td); 1069 } 1070 } 1071 return (NULL); 1072 } 1073 1074 /* 1075 * Attempt to steal a thread in priority order from a thread queue. 1076 */ 1077 static struct thread * 1078 tdq_steal(struct tdq *tdq, int cpu) 1079 { 1080 struct thread *td; 1081 1082 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1083 if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL) 1084 return (td); 1085 if ((td = runq_steal_from(&tdq->tdq_timeshare, 1086 cpu, tdq->tdq_ridx)) != NULL) 1087 return (td); 1088 return (runq_steal(&tdq->tdq_idle, cpu)); 1089 } 1090 1091 /* 1092 * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the 1093 * current lock and returns with the assigned queue locked. 1094 */ 1095 static inline struct tdq * 1096 sched_setcpu(struct thread *td, int cpu, int flags) 1097 { 1098 1099 struct tdq *tdq; 1100 1101 THREAD_LOCK_ASSERT(td, MA_OWNED); 1102 tdq = TDQ_CPU(cpu); 1103 td->td_sched->ts_cpu = cpu; 1104 /* 1105 * If the lock matches just return the queue. 1106 */ 1107 if (td->td_lock == TDQ_LOCKPTR(tdq)) 1108 return (tdq); 1109 #ifdef notyet 1110 /* 1111 * If the thread isn't running its lockptr is a 1112 * turnstile or a sleepqueue. We can just lock_set without 1113 * blocking. 1114 */ 1115 if (TD_CAN_RUN(td)) { 1116 TDQ_LOCK(tdq); 1117 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 1118 return (tdq); 1119 } 1120 #endif 1121 /* 1122 * The hard case, migration, we need to block the thread first to 1123 * prevent order reversals with other cpus locks. 1124 */ 1125 spinlock_enter(); 1126 thread_lock_block(td); 1127 TDQ_LOCK(tdq); 1128 thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); 1129 spinlock_exit(); 1130 return (tdq); 1131 } 1132 1133 SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding"); 1134 SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity"); 1135 SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity"); 1136 SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load"); 1137 SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu"); 1138 SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration"); 1139 1140 static int 1141 sched_pickcpu(struct thread *td, int flags) 1142 { 1143 struct cpu_group *cg; 1144 struct td_sched *ts; 1145 struct tdq *tdq; 1146 cpuset_t mask; 1147 int self; 1148 int pri; 1149 int cpu; 1150 1151 self = PCPU_GET(cpuid); 1152 ts = td->td_sched; 1153 if (smp_started == 0) 1154 return (self); 1155 /* 1156 * Don't migrate a running thread from sched_switch(). 1157 */ 1158 if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td)) 1159 return (ts->ts_cpu); 1160 /* 1161 * Prefer to run interrupt threads on the processors that generate 1162 * the interrupt. 1163 */ 1164 if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) && 1165 curthread->td_intr_nesting_level && ts->ts_cpu != self) { 1166 SCHED_STAT_INC(pickcpu_intrbind); 1167 ts->ts_cpu = self; 1168 } 1169 /* 1170 * If the thread can run on the last cpu and the affinity has not 1171 * expired or it is idle run it there. 1172 */ 1173 pri = td->td_priority; 1174 tdq = TDQ_CPU(ts->ts_cpu); 1175 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) { 1176 if (tdq->tdq_lowpri > PRI_MIN_IDLE) { 1177 SCHED_STAT_INC(pickcpu_idle_affinity); 1178 return (ts->ts_cpu); 1179 } 1180 if (SCHED_AFFINITY(ts, CG_SHARE_L2) && tdq->tdq_lowpri > pri) { 1181 SCHED_STAT_INC(pickcpu_affinity); 1182 return (ts->ts_cpu); 1183 } 1184 } 1185 /* 1186 * Search for the highest level in the tree that still has affinity. 1187 */ 1188 cg = NULL; 1189 for (cg = tdq->tdq_cg; cg != NULL; cg = cg->cg_parent) 1190 if (SCHED_AFFINITY(ts, cg->cg_level)) 1191 break; 1192 cpu = -1; 1193 mask = td->td_cpuset->cs_mask; 1194 if (cg) 1195 cpu = sched_lowest(cg, mask, pri); 1196 if (cpu == -1) 1197 cpu = sched_lowest(cpu_top, mask, -1); 1198 /* 1199 * Compare the lowest loaded cpu to current cpu. 1200 */ 1201 if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri && 1202 TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE) { 1203 SCHED_STAT_INC(pickcpu_local); 1204 cpu = self; 1205 } else 1206 SCHED_STAT_INC(pickcpu_lowest); 1207 if (cpu != ts->ts_cpu) 1208 SCHED_STAT_INC(pickcpu_migration); 1209 KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu.")); 1210 return (cpu); 1211 } 1212 #endif 1213 1214 /* 1215 * Pick the highest priority task we have and return it. 1216 */ 1217 static struct thread * 1218 tdq_choose(struct tdq *tdq) 1219 { 1220 struct thread *td; 1221 1222 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1223 td = runq_choose(&tdq->tdq_realtime); 1224 if (td != NULL) 1225 return (td); 1226 td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); 1227 if (td != NULL) { 1228 KASSERT(td->td_priority >= PRI_MIN_BATCH, 1229 ("tdq_choose: Invalid priority on timeshare queue %d", 1230 td->td_priority)); 1231 return (td); 1232 } 1233 td = runq_choose(&tdq->tdq_idle); 1234 if (td != NULL) { 1235 KASSERT(td->td_priority >= PRI_MIN_IDLE, 1236 ("tdq_choose: Invalid priority on idle queue %d", 1237 td->td_priority)); 1238 return (td); 1239 } 1240 1241 return (NULL); 1242 } 1243 1244 /* 1245 * Initialize a thread queue. 1246 */ 1247 static void 1248 tdq_setup(struct tdq *tdq) 1249 { 1250 1251 if (bootverbose) 1252 printf("ULE: setup cpu %d\n", TDQ_ID(tdq)); 1253 runq_init(&tdq->tdq_realtime); 1254 runq_init(&tdq->tdq_timeshare); 1255 runq_init(&tdq->tdq_idle); 1256 snprintf(tdq->tdq_name, sizeof(tdq->tdq_name), 1257 "sched lock %d", (int)TDQ_ID(tdq)); 1258 mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock", 1259 MTX_SPIN | MTX_RECURSE); 1260 #ifdef KTR 1261 snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname), 1262 "CPU %d load", (int)TDQ_ID(tdq)); 1263 #endif 1264 } 1265 1266 #ifdef SMP 1267 static void 1268 sched_setup_smp(void) 1269 { 1270 struct tdq *tdq; 1271 int i; 1272 1273 cpu_top = smp_topo(); 1274 CPU_FOREACH(i) { 1275 tdq = TDQ_CPU(i); 1276 tdq_setup(tdq); 1277 tdq->tdq_cg = smp_topo_find(cpu_top, i); 1278 if (tdq->tdq_cg == NULL) 1279 panic("Can't find cpu group for %d\n", i); 1280 } 1281 balance_tdq = TDQ_SELF(); 1282 sched_balance(); 1283 } 1284 #endif 1285 1286 /* 1287 * Setup the thread queues and initialize the topology based on MD 1288 * information. 1289 */ 1290 static void 1291 sched_setup(void *dummy) 1292 { 1293 struct tdq *tdq; 1294 1295 tdq = TDQ_SELF(); 1296 #ifdef SMP 1297 sched_setup_smp(); 1298 #else 1299 tdq_setup(tdq); 1300 #endif 1301 /* 1302 * To avoid divide-by-zero, we set realstathz a dummy value 1303 * in case which sched_clock() called before sched_initticks(). 1304 */ 1305 realstathz = hz; 1306 sched_slice = (realstathz/10); /* ~100ms */ 1307 tickincr = 1 << SCHED_TICK_SHIFT; 1308 1309 /* Add thread0's load since it's running. */ 1310 TDQ_LOCK(tdq); 1311 thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1312 tdq_load_add(tdq, &thread0); 1313 tdq->tdq_lowpri = thread0.td_priority; 1314 TDQ_UNLOCK(tdq); 1315 } 1316 1317 /* 1318 * This routine determines the tickincr after stathz and hz are setup. 1319 */ 1320 /* ARGSUSED */ 1321 static void 1322 sched_initticks(void *dummy) 1323 { 1324 int incr; 1325 1326 realstathz = stathz ? stathz : hz; 1327 sched_slice = (realstathz/10); /* ~100ms */ 1328 1329 /* 1330 * tickincr is shifted out by 10 to avoid rounding errors due to 1331 * hz not being evenly divisible by stathz on all platforms. 1332 */ 1333 incr = (hz << SCHED_TICK_SHIFT) / realstathz; 1334 /* 1335 * This does not work for values of stathz that are more than 1336 * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen. 1337 */ 1338 if (incr == 0) 1339 incr = 1; 1340 tickincr = incr; 1341 #ifdef SMP 1342 /* 1343 * Set the default balance interval now that we know 1344 * what realstathz is. 1345 */ 1346 balance_interval = realstathz; 1347 /* 1348 * Set steal thresh to roughly log2(mp_ncpu) but no greater than 4. 1349 * This prevents excess thrashing on large machines and excess idle 1350 * on smaller machines. 1351 */ 1352 steal_thresh = min(fls(mp_ncpus) - 1, 3); 1353 affinity = SCHED_AFFINITY_DEFAULT; 1354 #endif 1355 } 1356 1357 1358 /* 1359 * This is the core of the interactivity algorithm. Determines a score based 1360 * on past behavior. It is the ratio of sleep time to run time scaled to 1361 * a [0, 100] integer. This is the voluntary sleep time of a process, which 1362 * differs from the cpu usage because it does not account for time spent 1363 * waiting on a run-queue. Would be prettier if we had floating point. 1364 */ 1365 static int 1366 sched_interact_score(struct thread *td) 1367 { 1368 struct td_sched *ts; 1369 int div; 1370 1371 ts = td->td_sched; 1372 /* 1373 * The score is only needed if this is likely to be an interactive 1374 * task. Don't go through the expense of computing it if there's 1375 * no chance. 1376 */ 1377 if (sched_interact <= SCHED_INTERACT_HALF && 1378 ts->ts_runtime >= ts->ts_slptime) 1379 return (SCHED_INTERACT_HALF); 1380 1381 if (ts->ts_runtime > ts->ts_slptime) { 1382 div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF); 1383 return (SCHED_INTERACT_HALF + 1384 (SCHED_INTERACT_HALF - (ts->ts_slptime / div))); 1385 } 1386 if (ts->ts_slptime > ts->ts_runtime) { 1387 div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF); 1388 return (ts->ts_runtime / div); 1389 } 1390 /* runtime == slptime */ 1391 if (ts->ts_runtime) 1392 return (SCHED_INTERACT_HALF); 1393 1394 /* 1395 * This can happen if slptime and runtime are 0. 1396 */ 1397 return (0); 1398 1399 } 1400 1401 /* 1402 * Scale the scheduling priority according to the "interactivity" of this 1403 * process. 1404 */ 1405 static void 1406 sched_priority(struct thread *td) 1407 { 1408 int score; 1409 int pri; 1410 1411 if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE) 1412 return; 1413 /* 1414 * If the score is interactive we place the thread in the realtime 1415 * queue with a priority that is less than kernel and interrupt 1416 * priorities. These threads are not subject to nice restrictions. 1417 * 1418 * Scores greater than this are placed on the normal timeshare queue 1419 * where the priority is partially decided by the most recent cpu 1420 * utilization and the rest is decided by nice value. 1421 * 1422 * The nice value of the process has a linear effect on the calculated 1423 * score. Negative nice values make it easier for a thread to be 1424 * considered interactive. 1425 */ 1426 score = imax(0, sched_interact_score(td) + td->td_proc->p_nice); 1427 if (score < sched_interact) { 1428 pri = PRI_MIN_INTERACT; 1429 pri += ((PRI_MAX_INTERACT - PRI_MIN_INTERACT + 1) / 1430 sched_interact) * score; 1431 KASSERT(pri >= PRI_MIN_INTERACT && pri <= PRI_MAX_INTERACT, 1432 ("sched_priority: invalid interactive priority %d score %d", 1433 pri, score)); 1434 } else { 1435 pri = SCHED_PRI_MIN; 1436 if (td->td_sched->ts_ticks) 1437 pri += min(SCHED_PRI_TICKS(td->td_sched), 1438 SCHED_PRI_RANGE); 1439 pri += SCHED_PRI_NICE(td->td_proc->p_nice); 1440 KASSERT(pri >= PRI_MIN_BATCH && pri <= PRI_MAX_BATCH, 1441 ("sched_priority: invalid priority %d: nice %d, " 1442 "ticks %d ftick %d ltick %d tick pri %d", 1443 pri, td->td_proc->p_nice, td->td_sched->ts_ticks, 1444 td->td_sched->ts_ftick, td->td_sched->ts_ltick, 1445 SCHED_PRI_TICKS(td->td_sched))); 1446 } 1447 sched_user_prio(td, pri); 1448 1449 return; 1450 } 1451 1452 /* 1453 * This routine enforces a maximum limit on the amount of scheduling history 1454 * kept. It is called after either the slptime or runtime is adjusted. This 1455 * function is ugly due to integer math. 1456 */ 1457 static void 1458 sched_interact_update(struct thread *td) 1459 { 1460 struct td_sched *ts; 1461 u_int sum; 1462 1463 ts = td->td_sched; 1464 sum = ts->ts_runtime + ts->ts_slptime; 1465 if (sum < SCHED_SLP_RUN_MAX) 1466 return; 1467 /* 1468 * This only happens from two places: 1469 * 1) We have added an unusual amount of run time from fork_exit. 1470 * 2) We have added an unusual amount of sleep time from sched_sleep(). 1471 */ 1472 if (sum > SCHED_SLP_RUN_MAX * 2) { 1473 if (ts->ts_runtime > ts->ts_slptime) { 1474 ts->ts_runtime = SCHED_SLP_RUN_MAX; 1475 ts->ts_slptime = 1; 1476 } else { 1477 ts->ts_slptime = SCHED_SLP_RUN_MAX; 1478 ts->ts_runtime = 1; 1479 } 1480 return; 1481 } 1482 /* 1483 * If we have exceeded by more than 1/5th then the algorithm below 1484 * will not bring us back into range. Dividing by two here forces 1485 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] 1486 */ 1487 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { 1488 ts->ts_runtime /= 2; 1489 ts->ts_slptime /= 2; 1490 return; 1491 } 1492 ts->ts_runtime = (ts->ts_runtime / 5) * 4; 1493 ts->ts_slptime = (ts->ts_slptime / 5) * 4; 1494 } 1495 1496 /* 1497 * Scale back the interactivity history when a child thread is created. The 1498 * history is inherited from the parent but the thread may behave totally 1499 * differently. For example, a shell spawning a compiler process. We want 1500 * to learn that the compiler is behaving badly very quickly. 1501 */ 1502 static void 1503 sched_interact_fork(struct thread *td) 1504 { 1505 int ratio; 1506 int sum; 1507 1508 sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime; 1509 if (sum > SCHED_SLP_RUN_FORK) { 1510 ratio = sum / SCHED_SLP_RUN_FORK; 1511 td->td_sched->ts_runtime /= ratio; 1512 td->td_sched->ts_slptime /= ratio; 1513 } 1514 } 1515 1516 /* 1517 * Called from proc0_init() to setup the scheduler fields. 1518 */ 1519 void 1520 schedinit(void) 1521 { 1522 1523 /* 1524 * Set up the scheduler specific parts of proc0. 1525 */ 1526 proc0.p_sched = NULL; /* XXX */ 1527 thread0.td_sched = &td_sched0; 1528 td_sched0.ts_ltick = ticks; 1529 td_sched0.ts_ftick = ticks; 1530 td_sched0.ts_slice = sched_slice; 1531 } 1532 1533 /* 1534 * This is only somewhat accurate since given many processes of the same 1535 * priority they will switch when their slices run out, which will be 1536 * at most sched_slice stathz ticks. 1537 */ 1538 int 1539 sched_rr_interval(void) 1540 { 1541 1542 /* Convert sched_slice to hz */ 1543 return (hz/(realstathz/sched_slice)); 1544 } 1545 1546 /* 1547 * Update the percent cpu tracking information when it is requested or 1548 * the total history exceeds the maximum. We keep a sliding history of 1549 * tick counts that slowly decays. This is less precise than the 4BSD 1550 * mechanism since it happens with less regular and frequent events. 1551 */ 1552 static void 1553 sched_pctcpu_update(struct td_sched *ts) 1554 { 1555 1556 if (ts->ts_ticks == 0) 1557 return; 1558 if (ticks - (hz / 10) < ts->ts_ltick && 1559 SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX) 1560 return; 1561 /* 1562 * Adjust counters and watermark for pctcpu calc. 1563 */ 1564 if (ts->ts_ltick > ticks - SCHED_TICK_TARG) 1565 ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) * 1566 SCHED_TICK_TARG; 1567 else 1568 ts->ts_ticks = 0; 1569 ts->ts_ltick = ticks; 1570 ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG; 1571 } 1572 1573 /* 1574 * Adjust the priority of a thread. Move it to the appropriate run-queue 1575 * if necessary. This is the back-end for several priority related 1576 * functions. 1577 */ 1578 static void 1579 sched_thread_priority(struct thread *td, u_char prio) 1580 { 1581 struct td_sched *ts; 1582 struct tdq *tdq; 1583 int oldpri; 1584 1585 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio", 1586 "prio:%d", td->td_priority, "new prio:%d", prio, 1587 KTR_ATTR_LINKED, sched_tdname(curthread)); 1588 if (td != curthread && prio > td->td_priority) { 1589 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread), 1590 "lend prio", "prio:%d", td->td_priority, "new prio:%d", 1591 prio, KTR_ATTR_LINKED, sched_tdname(td)); 1592 } 1593 ts = td->td_sched; 1594 THREAD_LOCK_ASSERT(td, MA_OWNED); 1595 if (td->td_priority == prio) 1596 return; 1597 /* 1598 * If the priority has been elevated due to priority 1599 * propagation, we may have to move ourselves to a new 1600 * queue. This could be optimized to not re-add in some 1601 * cases. 1602 */ 1603 if (TD_ON_RUNQ(td) && prio < td->td_priority) { 1604 sched_rem(td); 1605 td->td_priority = prio; 1606 sched_add(td, SRQ_BORROWING); 1607 return; 1608 } 1609 /* 1610 * If the thread is currently running we may have to adjust the lowpri 1611 * information so other cpus are aware of our current priority. 1612 */ 1613 if (TD_IS_RUNNING(td)) { 1614 tdq = TDQ_CPU(ts->ts_cpu); 1615 oldpri = td->td_priority; 1616 td->td_priority = prio; 1617 if (prio < tdq->tdq_lowpri) 1618 tdq->tdq_lowpri = prio; 1619 else if (tdq->tdq_lowpri == oldpri) 1620 tdq_setlowpri(tdq, td); 1621 return; 1622 } 1623 td->td_priority = prio; 1624 } 1625 1626 /* 1627 * Update a thread's priority when it is lent another thread's 1628 * priority. 1629 */ 1630 void 1631 sched_lend_prio(struct thread *td, u_char prio) 1632 { 1633 1634 td->td_flags |= TDF_BORROWING; 1635 sched_thread_priority(td, prio); 1636 } 1637 1638 /* 1639 * Restore a thread's priority when priority propagation is 1640 * over. The prio argument is the minimum priority the thread 1641 * needs to have to satisfy other possible priority lending 1642 * requests. If the thread's regular priority is less 1643 * important than prio, the thread will keep a priority boost 1644 * of prio. 1645 */ 1646 void 1647 sched_unlend_prio(struct thread *td, u_char prio) 1648 { 1649 u_char base_pri; 1650 1651 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 1652 td->td_base_pri <= PRI_MAX_TIMESHARE) 1653 base_pri = td->td_user_pri; 1654 else 1655 base_pri = td->td_base_pri; 1656 if (prio >= base_pri) { 1657 td->td_flags &= ~TDF_BORROWING; 1658 sched_thread_priority(td, base_pri); 1659 } else 1660 sched_lend_prio(td, prio); 1661 } 1662 1663 /* 1664 * Standard entry for setting the priority to an absolute value. 1665 */ 1666 void 1667 sched_prio(struct thread *td, u_char prio) 1668 { 1669 u_char oldprio; 1670 1671 /* First, update the base priority. */ 1672 td->td_base_pri = prio; 1673 1674 /* 1675 * If the thread is borrowing another thread's priority, don't 1676 * ever lower the priority. 1677 */ 1678 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 1679 return; 1680 1681 /* Change the real priority. */ 1682 oldprio = td->td_priority; 1683 sched_thread_priority(td, prio); 1684 1685 /* 1686 * If the thread is on a turnstile, then let the turnstile update 1687 * its state. 1688 */ 1689 if (TD_ON_LOCK(td) && oldprio != prio) 1690 turnstile_adjust(td, oldprio); 1691 } 1692 1693 /* 1694 * Set the base user priority, does not effect current running priority. 1695 */ 1696 void 1697 sched_user_prio(struct thread *td, u_char prio) 1698 { 1699 1700 td->td_base_user_pri = prio; 1701 if (td->td_lend_user_pri <= prio) 1702 return; 1703 td->td_user_pri = prio; 1704 } 1705 1706 void 1707 sched_lend_user_prio(struct thread *td, u_char prio) 1708 { 1709 1710 THREAD_LOCK_ASSERT(td, MA_OWNED); 1711 td->td_lend_user_pri = prio; 1712 td->td_user_pri = min(prio, td->td_base_user_pri); 1713 if (td->td_priority > td->td_user_pri) 1714 sched_prio(td, td->td_user_pri); 1715 else if (td->td_priority != td->td_user_pri) 1716 td->td_flags |= TDF_NEEDRESCHED; 1717 } 1718 1719 /* 1720 * Handle migration from sched_switch(). This happens only for 1721 * cpu binding. 1722 */ 1723 static struct mtx * 1724 sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) 1725 { 1726 struct tdq *tdn; 1727 1728 tdn = TDQ_CPU(td->td_sched->ts_cpu); 1729 #ifdef SMP 1730 tdq_load_rem(tdq, td); 1731 /* 1732 * Do the lock dance required to avoid LOR. We grab an extra 1733 * spinlock nesting to prevent preemption while we're 1734 * not holding either run-queue lock. 1735 */ 1736 spinlock_enter(); 1737 thread_lock_block(td); /* This releases the lock on tdq. */ 1738 1739 /* 1740 * Acquire both run-queue locks before placing the thread on the new 1741 * run-queue to avoid deadlocks created by placing a thread with a 1742 * blocked lock on the run-queue of a remote processor. The deadlock 1743 * occurs when a third processor attempts to lock the two queues in 1744 * question while the target processor is spinning with its own 1745 * run-queue lock held while waiting for the blocked lock to clear. 1746 */ 1747 tdq_lock_pair(tdn, tdq); 1748 tdq_add(tdn, td, flags); 1749 tdq_notify(tdn, td); 1750 TDQ_UNLOCK(tdn); 1751 spinlock_exit(); 1752 #endif 1753 return (TDQ_LOCKPTR(tdn)); 1754 } 1755 1756 /* 1757 * Variadic version of thread_lock_unblock() that does not assume td_lock 1758 * is blocked. 1759 */ 1760 static inline void 1761 thread_unblock_switch(struct thread *td, struct mtx *mtx) 1762 { 1763 atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock, 1764 (uintptr_t)mtx); 1765 } 1766 1767 /* 1768 * Switch threads. This function has to handle threads coming in while 1769 * blocked for some reason, running, or idle. It also must deal with 1770 * migrating a thread from one queue to another as running threads may 1771 * be assigned elsewhere via binding. 1772 */ 1773 void 1774 sched_switch(struct thread *td, struct thread *newtd, int flags) 1775 { 1776 struct tdq *tdq; 1777 struct td_sched *ts; 1778 struct mtx *mtx; 1779 int srqflag; 1780 int cpuid; 1781 1782 THREAD_LOCK_ASSERT(td, MA_OWNED); 1783 KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument")); 1784 1785 cpuid = PCPU_GET(cpuid); 1786 tdq = TDQ_CPU(cpuid); 1787 ts = td->td_sched; 1788 mtx = td->td_lock; 1789 ts->ts_rltick = ticks; 1790 td->td_lastcpu = td->td_oncpu; 1791 td->td_oncpu = NOCPU; 1792 if (!(flags & SW_PREEMPT)) 1793 td->td_flags &= ~TDF_NEEDRESCHED; 1794 td->td_owepreempt = 0; 1795 tdq->tdq_switchcnt++; 1796 /* 1797 * The lock pointer in an idle thread should never change. Reset it 1798 * to CAN_RUN as well. 1799 */ 1800 if (TD_IS_IDLETHREAD(td)) { 1801 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1802 TD_SET_CAN_RUN(td); 1803 } else if (TD_IS_RUNNING(td)) { 1804 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1805 srqflag = (flags & SW_PREEMPT) ? 1806 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1807 SRQ_OURSELF|SRQ_YIELDING; 1808 #ifdef SMP 1809 if (THREAD_CAN_MIGRATE(td) && !THREAD_CAN_SCHED(td, ts->ts_cpu)) 1810 ts->ts_cpu = sched_pickcpu(td, 0); 1811 #endif 1812 if (ts->ts_cpu == cpuid) 1813 tdq_runq_add(tdq, td, srqflag); 1814 else { 1815 KASSERT(THREAD_CAN_MIGRATE(td) || 1816 (ts->ts_flags & TSF_BOUND) != 0, 1817 ("Thread %p shouldn't migrate", td)); 1818 mtx = sched_switch_migrate(tdq, td, srqflag); 1819 } 1820 } else { 1821 /* This thread must be going to sleep. */ 1822 TDQ_LOCK(tdq); 1823 mtx = thread_lock_block(td); 1824 tdq_load_rem(tdq, td); 1825 } 1826 /* 1827 * We enter here with the thread blocked and assigned to the 1828 * appropriate cpu run-queue or sleep-queue and with the current 1829 * thread-queue locked. 1830 */ 1831 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 1832 newtd = choosethread(); 1833 /* 1834 * Call the MD code to switch contexts if necessary. 1835 */ 1836 if (td != newtd) { 1837 #ifdef HWPMC_HOOKS 1838 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1839 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1840 #endif 1841 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 1842 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 1843 1844 #ifdef KDTRACE_HOOKS 1845 /* 1846 * If DTrace has set the active vtime enum to anything 1847 * other than INACTIVE (0), then it should have set the 1848 * function to call. 1849 */ 1850 if (dtrace_vtime_active) 1851 (*dtrace_vtime_switch_func)(newtd); 1852 #endif 1853 1854 cpu_switch(td, newtd, mtx); 1855 /* 1856 * We may return from cpu_switch on a different cpu. However, 1857 * we always return with td_lock pointing to the current cpu's 1858 * run queue lock. 1859 */ 1860 cpuid = PCPU_GET(cpuid); 1861 tdq = TDQ_CPU(cpuid); 1862 lock_profile_obtain_lock_success( 1863 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 1864 #ifdef HWPMC_HOOKS 1865 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1866 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1867 #endif 1868 } else 1869 thread_unblock_switch(td, mtx); 1870 /* 1871 * Assert that all went well and return. 1872 */ 1873 TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED); 1874 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1875 td->td_oncpu = cpuid; 1876 } 1877 1878 /* 1879 * Adjust thread priorities as a result of a nice request. 1880 */ 1881 void 1882 sched_nice(struct proc *p, int nice) 1883 { 1884 struct thread *td; 1885 1886 PROC_LOCK_ASSERT(p, MA_OWNED); 1887 1888 p->p_nice = nice; 1889 FOREACH_THREAD_IN_PROC(p, td) { 1890 thread_lock(td); 1891 sched_priority(td); 1892 sched_prio(td, td->td_base_user_pri); 1893 thread_unlock(td); 1894 } 1895 } 1896 1897 /* 1898 * Record the sleep time for the interactivity scorer. 1899 */ 1900 void 1901 sched_sleep(struct thread *td, int prio) 1902 { 1903 1904 THREAD_LOCK_ASSERT(td, MA_OWNED); 1905 1906 td->td_slptick = ticks; 1907 if (TD_IS_SUSPENDED(td) || prio >= PSOCK) 1908 td->td_flags |= TDF_CANSWAP; 1909 if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE) 1910 return; 1911 if (static_boost == 1 && prio) 1912 sched_prio(td, prio); 1913 else if (static_boost && td->td_priority > static_boost) 1914 sched_prio(td, static_boost); 1915 } 1916 1917 /* 1918 * Schedule a thread to resume execution and record how long it voluntarily 1919 * slept. We also update the pctcpu, interactivity, and priority. 1920 */ 1921 void 1922 sched_wakeup(struct thread *td) 1923 { 1924 struct td_sched *ts; 1925 int slptick; 1926 1927 THREAD_LOCK_ASSERT(td, MA_OWNED); 1928 ts = td->td_sched; 1929 td->td_flags &= ~TDF_CANSWAP; 1930 /* 1931 * If we slept for more than a tick update our interactivity and 1932 * priority. 1933 */ 1934 slptick = td->td_slptick; 1935 td->td_slptick = 0; 1936 if (slptick && slptick != ticks) { 1937 u_int hzticks; 1938 1939 hzticks = (ticks - slptick) << SCHED_TICK_SHIFT; 1940 ts->ts_slptime += hzticks; 1941 sched_interact_update(td); 1942 sched_pctcpu_update(ts); 1943 } 1944 /* Reset the slice value after we sleep. */ 1945 ts->ts_slice = sched_slice; 1946 sched_add(td, SRQ_BORING); 1947 } 1948 1949 /* 1950 * Penalize the parent for creating a new child and initialize the child's 1951 * priority. 1952 */ 1953 void 1954 sched_fork(struct thread *td, struct thread *child) 1955 { 1956 THREAD_LOCK_ASSERT(td, MA_OWNED); 1957 sched_fork_thread(td, child); 1958 /* 1959 * Penalize the parent and child for forking. 1960 */ 1961 sched_interact_fork(child); 1962 sched_priority(child); 1963 td->td_sched->ts_runtime += tickincr; 1964 sched_interact_update(td); 1965 sched_priority(td); 1966 } 1967 1968 /* 1969 * Fork a new thread, may be within the same process. 1970 */ 1971 void 1972 sched_fork_thread(struct thread *td, struct thread *child) 1973 { 1974 struct td_sched *ts; 1975 struct td_sched *ts2; 1976 1977 THREAD_LOCK_ASSERT(td, MA_OWNED); 1978 /* 1979 * Initialize child. 1980 */ 1981 ts = td->td_sched; 1982 ts2 = child->td_sched; 1983 child->td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1984 child->td_cpuset = cpuset_ref(td->td_cpuset); 1985 ts2->ts_cpu = ts->ts_cpu; 1986 ts2->ts_flags = 0; 1987 /* 1988 * Grab our parents cpu estimation information. 1989 */ 1990 ts2->ts_ticks = ts->ts_ticks; 1991 ts2->ts_ltick = ts->ts_ltick; 1992 ts2->ts_incrtick = ts->ts_incrtick; 1993 ts2->ts_ftick = ts->ts_ftick; 1994 /* 1995 * Do not inherit any borrowed priority from the parent. 1996 */ 1997 child->td_priority = child->td_base_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 #ifdef KTR 2005 bzero(ts2->ts_name, sizeof(ts2->ts_name)); 2006 #endif 2007 } 2008 2009 /* 2010 * Adjust the priority class of a thread. 2011 */ 2012 void 2013 sched_class(struct thread *td, int class) 2014 { 2015 2016 THREAD_LOCK_ASSERT(td, MA_OWNED); 2017 if (td->td_pri_class == class) 2018 return; 2019 td->td_pri_class = class; 2020 } 2021 2022 /* 2023 * Return some of the child's priority and interactivity to the parent. 2024 */ 2025 void 2026 sched_exit(struct proc *p, struct thread *child) 2027 { 2028 struct thread *td; 2029 2030 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit", 2031 "prio:%d", child->td_priority); 2032 PROC_LOCK_ASSERT(p, MA_OWNED); 2033 td = FIRST_THREAD_IN_PROC(p); 2034 sched_exit_thread(td, child); 2035 } 2036 2037 /* 2038 * Penalize another thread for the time spent on this one. This helps to 2039 * worsen the priority and interactivity of processes which schedule batch 2040 * jobs such as make. This has little effect on the make process itself but 2041 * causes new processes spawned by it to receive worse scores immediately. 2042 */ 2043 void 2044 sched_exit_thread(struct thread *td, struct thread *child) 2045 { 2046 2047 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit", 2048 "prio:%d", child->td_priority); 2049 /* 2050 * Give the child's runtime to the parent without returning the 2051 * sleep time as a penalty to the parent. This causes shells that 2052 * launch expensive things to mark their children as expensive. 2053 */ 2054 thread_lock(td); 2055 td->td_sched->ts_runtime += child->td_sched->ts_runtime; 2056 sched_interact_update(td); 2057 sched_priority(td); 2058 thread_unlock(td); 2059 } 2060 2061 void 2062 sched_preempt(struct thread *td) 2063 { 2064 struct tdq *tdq; 2065 2066 thread_lock(td); 2067 tdq = TDQ_SELF(); 2068 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2069 tdq->tdq_ipipending = 0; 2070 if (td->td_priority > tdq->tdq_lowpri) { 2071 int flags; 2072 2073 flags = SW_INVOL | SW_PREEMPT; 2074 if (td->td_critnest > 1) 2075 td->td_owepreempt = 1; 2076 else if (TD_IS_IDLETHREAD(td)) 2077 mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL); 2078 else 2079 mi_switch(flags | SWT_REMOTEPREEMPT, NULL); 2080 } 2081 thread_unlock(td); 2082 } 2083 2084 /* 2085 * Fix priorities on return to user-space. Priorities may be elevated due 2086 * to static priorities in msleep() or similar. 2087 */ 2088 void 2089 sched_userret(struct thread *td) 2090 { 2091 /* 2092 * XXX we cheat slightly on the locking here to avoid locking in 2093 * the usual case. Setting td_priority here is essentially an 2094 * incomplete workaround for not setting it properly elsewhere. 2095 * Now that some interrupt handlers are threads, not setting it 2096 * properly elsewhere can clobber it in the window between setting 2097 * it here and returning to user mode, so don't waste time setting 2098 * it perfectly here. 2099 */ 2100 KASSERT((td->td_flags & TDF_BORROWING) == 0, 2101 ("thread with borrowed priority returning to userland")); 2102 if (td->td_priority != td->td_user_pri) { 2103 thread_lock(td); 2104 td->td_priority = td->td_user_pri; 2105 td->td_base_pri = td->td_user_pri; 2106 tdq_setlowpri(TDQ_SELF(), td); 2107 thread_unlock(td); 2108 } 2109 } 2110 2111 /* 2112 * Handle a stathz tick. This is really only relevant for timeshare 2113 * threads. 2114 */ 2115 void 2116 sched_clock(struct thread *td) 2117 { 2118 struct tdq *tdq; 2119 struct td_sched *ts; 2120 2121 THREAD_LOCK_ASSERT(td, MA_OWNED); 2122 tdq = TDQ_SELF(); 2123 #ifdef SMP 2124 /* 2125 * We run the long term load balancer infrequently on the first cpu. 2126 */ 2127 if (balance_tdq == tdq) { 2128 if (balance_ticks && --balance_ticks == 0) 2129 sched_balance(); 2130 } 2131 #endif 2132 /* 2133 * Save the old switch count so we have a record of the last ticks 2134 * activity. Initialize the new switch count based on our load. 2135 * If there is some activity seed it to reflect that. 2136 */ 2137 tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt; 2138 tdq->tdq_switchcnt = tdq->tdq_load; 2139 /* 2140 * Advance the insert index once for each tick to ensure that all 2141 * threads get a chance to run. 2142 */ 2143 if (tdq->tdq_idx == tdq->tdq_ridx) { 2144 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; 2145 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) 2146 tdq->tdq_ridx = tdq->tdq_idx; 2147 } 2148 ts = td->td_sched; 2149 if (td->td_pri_class & PRI_FIFO_BIT) 2150 return; 2151 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) { 2152 /* 2153 * We used a tick; charge it to the thread so 2154 * that we can compute our interactivity. 2155 */ 2156 td->td_sched->ts_runtime += tickincr; 2157 sched_interact_update(td); 2158 sched_priority(td); 2159 } 2160 /* 2161 * We used up one time slice. 2162 */ 2163 if (--ts->ts_slice > 0) 2164 return; 2165 /* 2166 * We're out of time, force a requeue at userret(). 2167 */ 2168 ts->ts_slice = sched_slice; 2169 td->td_flags |= TDF_NEEDRESCHED; 2170 } 2171 2172 /* 2173 * Called once per hz tick. Used for cpu utilization information. This 2174 * is easier than trying to scale based on stathz. 2175 */ 2176 void 2177 sched_tick(int cnt) 2178 { 2179 struct td_sched *ts; 2180 2181 ts = curthread->td_sched; 2182 /* 2183 * Ticks is updated asynchronously on a single cpu. Check here to 2184 * avoid incrementing ts_ticks multiple times in a single tick. 2185 */ 2186 if (ts->ts_incrtick == ticks) 2187 return; 2188 /* Adjust ticks for pctcpu */ 2189 ts->ts_ticks += cnt << SCHED_TICK_SHIFT; 2190 ts->ts_ltick = ticks; 2191 ts->ts_incrtick = ticks; 2192 /* 2193 * Update if we've exceeded our desired tick threshold by over one 2194 * second. 2195 */ 2196 if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick) 2197 sched_pctcpu_update(ts); 2198 } 2199 2200 /* 2201 * Return whether the current CPU has runnable tasks. Used for in-kernel 2202 * cooperative idle threads. 2203 */ 2204 int 2205 sched_runnable(void) 2206 { 2207 struct tdq *tdq; 2208 int load; 2209 2210 load = 1; 2211 2212 tdq = TDQ_SELF(); 2213 if ((curthread->td_flags & TDF_IDLETD) != 0) { 2214 if (tdq->tdq_load > 0) 2215 goto out; 2216 } else 2217 if (tdq->tdq_load - 1 > 0) 2218 goto out; 2219 load = 0; 2220 out: 2221 return (load); 2222 } 2223 2224 /* 2225 * Choose the highest priority thread to run. The thread is removed from 2226 * the run-queue while running however the load remains. For SMP we set 2227 * the tdq in the global idle bitmask if it idles here. 2228 */ 2229 struct thread * 2230 sched_choose(void) 2231 { 2232 struct thread *td; 2233 struct tdq *tdq; 2234 2235 tdq = TDQ_SELF(); 2236 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2237 td = tdq_choose(tdq); 2238 if (td) { 2239 td->td_sched->ts_ltick = ticks; 2240 tdq_runq_rem(tdq, td); 2241 tdq->tdq_lowpri = td->td_priority; 2242 return (td); 2243 } 2244 tdq->tdq_lowpri = PRI_MAX_IDLE; 2245 return (PCPU_GET(idlethread)); 2246 } 2247 2248 /* 2249 * Set owepreempt if necessary. Preemption never happens directly in ULE, 2250 * we always request it once we exit a critical section. 2251 */ 2252 static inline void 2253 sched_setpreempt(struct thread *td) 2254 { 2255 struct thread *ctd; 2256 int cpri; 2257 int pri; 2258 2259 THREAD_LOCK_ASSERT(curthread, MA_OWNED); 2260 2261 ctd = curthread; 2262 pri = td->td_priority; 2263 cpri = ctd->td_priority; 2264 if (pri < cpri) 2265 ctd->td_flags |= TDF_NEEDRESCHED; 2266 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) 2267 return; 2268 if (!sched_shouldpreempt(pri, cpri, 0)) 2269 return; 2270 ctd->td_owepreempt = 1; 2271 } 2272 2273 /* 2274 * Add a thread to a thread queue. Select the appropriate runq and add the 2275 * thread to it. This is the internal function called when the tdq is 2276 * predetermined. 2277 */ 2278 void 2279 tdq_add(struct tdq *tdq, struct thread *td, int flags) 2280 { 2281 2282 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2283 KASSERT((td->td_inhibitors == 0), 2284 ("sched_add: trying to run inhibited thread")); 2285 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 2286 ("sched_add: bad thread state")); 2287 KASSERT(td->td_flags & TDF_INMEM, 2288 ("sched_add: thread swapped out")); 2289 2290 if (td->td_priority < tdq->tdq_lowpri) 2291 tdq->tdq_lowpri = td->td_priority; 2292 tdq_runq_add(tdq, td, flags); 2293 tdq_load_add(tdq, td); 2294 } 2295 2296 /* 2297 * Select the target thread queue and add a thread to it. Request 2298 * preemption or IPI a remote processor if required. 2299 */ 2300 void 2301 sched_add(struct thread *td, int flags) 2302 { 2303 struct tdq *tdq; 2304 #ifdef SMP 2305 int cpu; 2306 #endif 2307 2308 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", 2309 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 2310 sched_tdname(curthread)); 2311 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup", 2312 KTR_ATTR_LINKED, sched_tdname(td)); 2313 THREAD_LOCK_ASSERT(td, MA_OWNED); 2314 /* 2315 * Recalculate the priority before we select the target cpu or 2316 * run-queue. 2317 */ 2318 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 2319 sched_priority(td); 2320 #ifdef SMP 2321 /* 2322 * Pick the destination cpu and if it isn't ours transfer to the 2323 * target cpu. 2324 */ 2325 cpu = sched_pickcpu(td, flags); 2326 tdq = sched_setcpu(td, cpu, flags); 2327 tdq_add(tdq, td, flags); 2328 if (cpu != PCPU_GET(cpuid)) { 2329 tdq_notify(tdq, td); 2330 return; 2331 } 2332 #else 2333 tdq = TDQ_SELF(); 2334 TDQ_LOCK(tdq); 2335 /* 2336 * Now that the thread is moving to the run-queue, set the lock 2337 * to the scheduler's lock. 2338 */ 2339 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 2340 tdq_add(tdq, td, flags); 2341 #endif 2342 if (!(flags & SRQ_YIELDING)) 2343 sched_setpreempt(td); 2344 } 2345 2346 /* 2347 * Remove a thread from a run-queue without running it. This is used 2348 * when we're stealing a thread from a remote queue. Otherwise all threads 2349 * exit by calling sched_exit_thread() and sched_throw() themselves. 2350 */ 2351 void 2352 sched_rem(struct thread *td) 2353 { 2354 struct tdq *tdq; 2355 2356 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem", 2357 "prio:%d", td->td_priority); 2358 tdq = TDQ_CPU(td->td_sched->ts_cpu); 2359 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2360 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2361 KASSERT(TD_ON_RUNQ(td), 2362 ("sched_rem: thread not on run queue")); 2363 tdq_runq_rem(tdq, td); 2364 tdq_load_rem(tdq, td); 2365 TD_SET_CAN_RUN(td); 2366 if (td->td_priority == tdq->tdq_lowpri) 2367 tdq_setlowpri(tdq, NULL); 2368 } 2369 2370 /* 2371 * Fetch cpu utilization information. Updates on demand. 2372 */ 2373 fixpt_t 2374 sched_pctcpu(struct thread *td) 2375 { 2376 fixpt_t pctcpu; 2377 struct td_sched *ts; 2378 2379 pctcpu = 0; 2380 ts = td->td_sched; 2381 if (ts == NULL) 2382 return (0); 2383 2384 THREAD_LOCK_ASSERT(td, MA_OWNED); 2385 if (ts->ts_ticks) { 2386 int rtick; 2387 2388 sched_pctcpu_update(ts); 2389 /* How many rtick per second ? */ 2390 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); 2391 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; 2392 } 2393 2394 return (pctcpu); 2395 } 2396 2397 /* 2398 * Enforce affinity settings for a thread. Called after adjustments to 2399 * cpumask. 2400 */ 2401 void 2402 sched_affinity(struct thread *td) 2403 { 2404 #ifdef SMP 2405 struct td_sched *ts; 2406 2407 THREAD_LOCK_ASSERT(td, MA_OWNED); 2408 ts = td->td_sched; 2409 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) 2410 return; 2411 if (TD_ON_RUNQ(td)) { 2412 sched_rem(td); 2413 sched_add(td, SRQ_BORING); 2414 return; 2415 } 2416 if (!TD_IS_RUNNING(td)) 2417 return; 2418 /* 2419 * Force a switch before returning to userspace. If the 2420 * target thread is not running locally send an ipi to force 2421 * the issue. 2422 */ 2423 td->td_flags |= TDF_NEEDRESCHED; 2424 if (td != curthread) 2425 ipi_cpu(ts->ts_cpu, IPI_PREEMPT); 2426 #endif 2427 } 2428 2429 /* 2430 * Bind a thread to a target cpu. 2431 */ 2432 void 2433 sched_bind(struct thread *td, int cpu) 2434 { 2435 struct td_sched *ts; 2436 2437 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 2438 KASSERT(td == curthread, ("sched_bind: can only bind curthread")); 2439 ts = td->td_sched; 2440 if (ts->ts_flags & TSF_BOUND) 2441 sched_unbind(td); 2442 KASSERT(THREAD_CAN_MIGRATE(td), ("%p must be migratable", td)); 2443 ts->ts_flags |= TSF_BOUND; 2444 sched_pin(); 2445 if (PCPU_GET(cpuid) == cpu) 2446 return; 2447 ts->ts_cpu = cpu; 2448 /* When we return from mi_switch we'll be on the correct cpu. */ 2449 mi_switch(SW_VOL, NULL); 2450 } 2451 2452 /* 2453 * Release a bound thread. 2454 */ 2455 void 2456 sched_unbind(struct thread *td) 2457 { 2458 struct td_sched *ts; 2459 2460 THREAD_LOCK_ASSERT(td, MA_OWNED); 2461 KASSERT(td == curthread, ("sched_unbind: can only bind curthread")); 2462 ts = td->td_sched; 2463 if ((ts->ts_flags & TSF_BOUND) == 0) 2464 return; 2465 ts->ts_flags &= ~TSF_BOUND; 2466 sched_unpin(); 2467 } 2468 2469 int 2470 sched_is_bound(struct thread *td) 2471 { 2472 THREAD_LOCK_ASSERT(td, MA_OWNED); 2473 return (td->td_sched->ts_flags & TSF_BOUND); 2474 } 2475 2476 /* 2477 * Basic yield call. 2478 */ 2479 void 2480 sched_relinquish(struct thread *td) 2481 { 2482 thread_lock(td); 2483 mi_switch(SW_VOL | SWT_RELINQUISH, NULL); 2484 thread_unlock(td); 2485 } 2486 2487 /* 2488 * Return the total system load. 2489 */ 2490 int 2491 sched_load(void) 2492 { 2493 #ifdef SMP 2494 int total; 2495 int i; 2496 2497 total = 0; 2498 CPU_FOREACH(i) 2499 total += TDQ_CPU(i)->tdq_sysload; 2500 return (total); 2501 #else 2502 return (TDQ_SELF()->tdq_sysload); 2503 #endif 2504 } 2505 2506 int 2507 sched_sizeof_proc(void) 2508 { 2509 return (sizeof(struct proc)); 2510 } 2511 2512 int 2513 sched_sizeof_thread(void) 2514 { 2515 return (sizeof(struct thread) + sizeof(struct td_sched)); 2516 } 2517 2518 #ifdef SMP 2519 #define TDQ_IDLESPIN(tdq) \ 2520 ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0) 2521 #else 2522 #define TDQ_IDLESPIN(tdq) 1 2523 #endif 2524 2525 /* 2526 * The actual idle process. 2527 */ 2528 void 2529 sched_idletd(void *dummy) 2530 { 2531 struct thread *td; 2532 struct tdq *tdq; 2533 int switchcnt; 2534 int i; 2535 2536 mtx_assert(&Giant, MA_NOTOWNED); 2537 td = curthread; 2538 tdq = TDQ_SELF(); 2539 for (;;) { 2540 #ifdef SMP 2541 if (tdq_idled(tdq) == 0) 2542 continue; 2543 #endif 2544 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2545 /* 2546 * If we're switching very frequently, spin while checking 2547 * for load rather than entering a low power state that 2548 * may require an IPI. However, don't do any busy 2549 * loops while on SMT machines as this simply steals 2550 * cycles from cores doing useful work. 2551 */ 2552 if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) { 2553 for (i = 0; i < sched_idlespins; i++) { 2554 if (tdq->tdq_load) 2555 break; 2556 cpu_spinwait(); 2557 } 2558 } 2559 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2560 if (tdq->tdq_load == 0) { 2561 tdq->tdq_cpu_idle = 1; 2562 if (tdq->tdq_load == 0) { 2563 cpu_idle(switchcnt > sched_idlespinthresh * 4); 2564 tdq->tdq_switchcnt++; 2565 } 2566 tdq->tdq_cpu_idle = 0; 2567 } 2568 if (tdq->tdq_load) { 2569 thread_lock(td); 2570 mi_switch(SW_VOL | SWT_IDLE, NULL); 2571 thread_unlock(td); 2572 } 2573 } 2574 } 2575 2576 /* 2577 * A CPU is entering for the first time or a thread is exiting. 2578 */ 2579 void 2580 sched_throw(struct thread *td) 2581 { 2582 struct thread *newtd; 2583 struct tdq *tdq; 2584 2585 tdq = TDQ_SELF(); 2586 if (td == NULL) { 2587 /* Correct spinlock nesting and acquire the correct lock. */ 2588 TDQ_LOCK(tdq); 2589 spinlock_exit(); 2590 PCPU_SET(switchtime, cpu_ticks()); 2591 PCPU_SET(switchticks, ticks); 2592 } else { 2593 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2594 tdq_load_rem(tdq, td); 2595 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 2596 } 2597 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 2598 newtd = choosethread(); 2599 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 2600 cpu_throw(td, newtd); /* doesn't return */ 2601 } 2602 2603 /* 2604 * This is called from fork_exit(). Just acquire the correct locks and 2605 * let fork do the rest of the work. 2606 */ 2607 void 2608 sched_fork_exit(struct thread *td) 2609 { 2610 struct td_sched *ts; 2611 struct tdq *tdq; 2612 int cpuid; 2613 2614 /* 2615 * Finish setting up thread glue so that it begins execution in a 2616 * non-nested critical section with the scheduler lock held. 2617 */ 2618 cpuid = PCPU_GET(cpuid); 2619 tdq = TDQ_CPU(cpuid); 2620 ts = td->td_sched; 2621 if (TD_IS_IDLETHREAD(td)) 2622 td->td_lock = TDQ_LOCKPTR(tdq); 2623 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2624 td->td_oncpu = cpuid; 2625 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 2626 lock_profile_obtain_lock_success( 2627 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 2628 } 2629 2630 /* 2631 * Create on first use to catch odd startup conditons. 2632 */ 2633 char * 2634 sched_tdname(struct thread *td) 2635 { 2636 #ifdef KTR 2637 struct td_sched *ts; 2638 2639 ts = td->td_sched; 2640 if (ts->ts_name[0] == '\0') 2641 snprintf(ts->ts_name, sizeof(ts->ts_name), 2642 "%s tid %d", td->td_name, td->td_tid); 2643 return (ts->ts_name); 2644 #else 2645 return (td->td_name); 2646 #endif 2647 } 2648 2649 #ifdef SMP 2650 2651 /* 2652 * Build the CPU topology dump string. Is recursively called to collect 2653 * the topology tree. 2654 */ 2655 static int 2656 sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg, 2657 int indent) 2658 { 2659 char cpusetbuf[CPUSETBUFSIZ]; 2660 int i, first; 2661 2662 sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent, 2663 "", 1 + indent / 2, cg->cg_level); 2664 sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"%s\">", indent, "", 2665 cg->cg_count, cpusetobj_strprint(cpusetbuf, &cg->cg_mask)); 2666 first = TRUE; 2667 for (i = 0; i < MAXCPU; i++) { 2668 if (CPU_ISSET(i, &cg->cg_mask)) { 2669 if (!first) 2670 sbuf_printf(sb, ", "); 2671 else 2672 first = FALSE; 2673 sbuf_printf(sb, "%d", i); 2674 } 2675 } 2676 sbuf_printf(sb, "</cpu>\n"); 2677 2678 if (cg->cg_flags != 0) { 2679 sbuf_printf(sb, "%*s <flags>", indent, ""); 2680 if ((cg->cg_flags & CG_FLAG_HTT) != 0) 2681 sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>"); 2682 if ((cg->cg_flags & CG_FLAG_THREAD) != 0) 2683 sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>"); 2684 if ((cg->cg_flags & CG_FLAG_SMT) != 0) 2685 sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>"); 2686 sbuf_printf(sb, "</flags>\n"); 2687 } 2688 2689 if (cg->cg_children > 0) { 2690 sbuf_printf(sb, "%*s <children>\n", indent, ""); 2691 for (i = 0; i < cg->cg_children; i++) 2692 sysctl_kern_sched_topology_spec_internal(sb, 2693 &cg->cg_child[i], indent+2); 2694 sbuf_printf(sb, "%*s </children>\n", indent, ""); 2695 } 2696 sbuf_printf(sb, "%*s</group>\n", indent, ""); 2697 return (0); 2698 } 2699 2700 /* 2701 * Sysctl handler for retrieving topology dump. It's a wrapper for 2702 * the recursive sysctl_kern_smp_topology_spec_internal(). 2703 */ 2704 static int 2705 sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS) 2706 { 2707 struct sbuf *topo; 2708 int err; 2709 2710 KASSERT(cpu_top != NULL, ("cpu_top isn't initialized")); 2711 2712 topo = sbuf_new(NULL, NULL, 500, SBUF_AUTOEXTEND); 2713 if (topo == NULL) 2714 return (ENOMEM); 2715 2716 sbuf_printf(topo, "<groups>\n"); 2717 err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1); 2718 sbuf_printf(topo, "</groups>\n"); 2719 2720 if (err == 0) { 2721 sbuf_finish(topo); 2722 err = SYSCTL_OUT(req, sbuf_data(topo), sbuf_len(topo)); 2723 } 2724 sbuf_delete(topo); 2725 return (err); 2726 } 2727 2728 #endif 2729 2730 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); 2731 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0, 2732 "Scheduler name"); 2733 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 2734 "Slice size for timeshare threads"); 2735 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, 2736 "Interactivity score threshold"); 2737 SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh, 2738 0,"Min priority for preemption, lower priorities have greater precedence"); 2739 SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 2740 0,"Controls whether static kernel priorities are assigned to sleeping threads."); 2741 SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 2742 0,"Number of times idle will spin waiting for new work."); 2743 SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW, &sched_idlespinthresh, 2744 0,"Threshold before we will permit idle spinning."); 2745 #ifdef SMP 2746 SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0, 2747 "Number of hz ticks to keep thread affinity for"); 2748 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, 2749 "Enables the long-term load balancer"); 2750 SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW, 2751 &balance_interval, 0, 2752 "Average frequency in stathz ticks to run the long-term balancer"); 2753 SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0, 2754 "Steals work from another hyper-threaded core on idle"); 2755 SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0, 2756 "Attempts to steal work from other cores before idling"); 2757 SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0, 2758 "Minimum load on remote cpu before we'll steal"); 2759 2760 /* Retrieve SMP topology */ 2761 SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING | 2762 CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A", 2763 "XML dump of detected CPU topology"); 2764 2765 #endif 2766 2767 /* ps compat. All cpu percentages from ULE are weighted. */ 2768 static int ccpu = 0; 2769 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 2770