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(__sparc64__) 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 (PCPU_NAME_LEN + 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 * Cpu percentage computation macros and defines. 121 * 122 * SCHED_TICK_SECS: Number of seconds to average the cpu usage across. 123 * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across. 124 * SCHED_TICK_MAX: Maximum number of ticks before scaling back. 125 * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results. 126 * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count. 127 * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks. 128 */ 129 #define SCHED_TICK_SECS 10 130 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS) 131 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz) 132 #define SCHED_TICK_SHIFT 10 133 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT) 134 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz)) 135 136 /* 137 * These macros determine priorities for non-interactive threads. They are 138 * assigned a priority based on their recent cpu utilization as expressed 139 * by the ratio of ticks to the tick total. NHALF priorities at the start 140 * and end of the MIN to MAX timeshare range are only reachable with negative 141 * or positive nice respectively. 142 * 143 * PRI_RANGE: Priority range for utilization dependent priorities. 144 * PRI_NRESV: Number of nice values. 145 * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total. 146 * PRI_NICE: Determines the part of the priority inherited from nice. 147 */ 148 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN) 149 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) 150 #define SCHED_PRI_MIN (PRI_MIN_TIMESHARE + SCHED_PRI_NHALF) 151 #define SCHED_PRI_MAX (PRI_MAX_TIMESHARE - SCHED_PRI_NHALF) 152 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN) 153 #define SCHED_PRI_TICKS(ts) \ 154 (SCHED_TICK_HZ((ts)) / \ 155 (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE)) 156 #define SCHED_PRI_NICE(nice) (nice) 157 158 /* 159 * These determine the interactivity of a process. Interactivity differs from 160 * cpu utilization in that it expresses the voluntary time slept vs time ran 161 * while cpu utilization includes all time not running. This more accurately 162 * models the intent of the thread. 163 * 164 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 165 * before throttling back. 166 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. 167 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 168 * INTERACT_THRESH: Threshhold for placement on the current runq. 169 */ 170 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT) 171 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT) 172 #define SCHED_INTERACT_MAX (100) 173 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 174 #define SCHED_INTERACT_THRESH (30) 175 176 /* 177 * tickincr: Converts a stathz tick into a hz domain scaled by 178 * the shift factor. Without the shift the error rate 179 * due to rounding would be unacceptably high. 180 * realstathz: stathz is sometimes 0 and run off of hz. 181 * sched_slice: Runtime of each thread before rescheduling. 182 * preempt_thresh: Priority threshold for preemption and remote IPIs. 183 */ 184 static int sched_interact = SCHED_INTERACT_THRESH; 185 static int realstathz; 186 static int tickincr; 187 static int sched_slice = 1; 188 #ifdef PREEMPTION 189 #ifdef FULL_PREEMPTION 190 static int preempt_thresh = PRI_MAX_IDLE; 191 #else 192 static int preempt_thresh = PRI_MIN_KERN; 193 #endif 194 #else 195 static int preempt_thresh = 0; 196 #endif 197 static int static_boost = PRI_MIN_TIMESHARE; 198 static int sched_idlespins = 10000; 199 static int sched_idlespinthresh = 4; 200 201 /* 202 * tdq - per processor runqs and statistics. All fields are protected by the 203 * tdq_lock. The load and lowpri may be accessed without to avoid excess 204 * locking in sched_pickcpu(); 205 */ 206 struct tdq { 207 /* Ordered to improve efficiency of cpu_search() and switch(). */ 208 struct mtx tdq_lock; /* run queue lock. */ 209 struct cpu_group *tdq_cg; /* Pointer to cpu topology. */ 210 volatile int tdq_load; /* Aggregate load. */ 211 int tdq_sysload; /* For loadavg, !ITHD load. */ 212 int tdq_transferable; /* Transferable thread count. */ 213 short tdq_switchcnt; /* Switches this tick. */ 214 short tdq_oldswitchcnt; /* Switches last tick. */ 215 u_char tdq_lowpri; /* Lowest priority thread. */ 216 u_char tdq_ipipending; /* IPI pending. */ 217 u_char tdq_idx; /* Current insert index. */ 218 u_char tdq_ridx; /* Current removal index. */ 219 struct runq tdq_realtime; /* real-time run queue. */ 220 struct runq tdq_timeshare; /* timeshare run queue. */ 221 struct runq tdq_idle; /* Queue of IDLE threads. */ 222 char tdq_name[TDQ_NAME_LEN]; 223 #ifdef KTR 224 char tdq_loadname[TDQ_LOADNAME_LEN]; 225 #endif 226 } __aligned(64); 227 228 /* Idle thread states and config. */ 229 #define TDQ_RUNNING 1 230 #define TDQ_IDLE 2 231 232 #ifdef SMP 233 struct cpu_group *cpu_top; /* CPU topology */ 234 235 #define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000)) 236 #define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity)) 237 238 /* 239 * Run-time tunables. 240 */ 241 static int rebalance = 1; 242 static int balance_interval = 128; /* Default set in sched_initticks(). */ 243 static int affinity; 244 static int steal_htt = 1; 245 static int steal_idle = 1; 246 static int steal_thresh = 2; 247 248 /* 249 * One thread queue per processor. 250 */ 251 static struct tdq tdq_cpu[MAXCPU]; 252 static struct tdq *balance_tdq; 253 static int balance_ticks; 254 255 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)]) 256 #define TDQ_CPU(x) (&tdq_cpu[(x)]) 257 #define TDQ_ID(x) ((int)((x) - tdq_cpu)) 258 #else /* !SMP */ 259 static struct tdq tdq_cpu; 260 261 #define TDQ_ID(x) (0) 262 #define TDQ_SELF() (&tdq_cpu) 263 #define TDQ_CPU(x) (&tdq_cpu) 264 #endif 265 266 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type)) 267 #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t))) 268 #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f)) 269 #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t))) 270 #define TDQ_LOCKPTR(t) (&(t)->tdq_lock) 271 272 static void sched_priority(struct thread *); 273 static void sched_thread_priority(struct thread *, u_char); 274 static int sched_interact_score(struct thread *); 275 static void sched_interact_update(struct thread *); 276 static void sched_interact_fork(struct thread *); 277 static void sched_pctcpu_update(struct td_sched *); 278 279 /* Operations on per processor queues */ 280 static struct thread *tdq_choose(struct tdq *); 281 static void tdq_setup(struct tdq *); 282 static void tdq_load_add(struct tdq *, struct thread *); 283 static void tdq_load_rem(struct tdq *, struct thread *); 284 static __inline void tdq_runq_add(struct tdq *, struct thread *, int); 285 static __inline void tdq_runq_rem(struct tdq *, struct thread *); 286 static inline int sched_shouldpreempt(int, int, int); 287 void tdq_print(int cpu); 288 static void runq_print(struct runq *rq); 289 static void tdq_add(struct tdq *, struct thread *, int); 290 #ifdef SMP 291 static int tdq_move(struct tdq *, struct tdq *); 292 static int tdq_idled(struct tdq *); 293 static void tdq_notify(struct tdq *, struct thread *); 294 static struct thread *tdq_steal(struct tdq *, int); 295 static struct thread *runq_steal(struct runq *, int); 296 static int sched_pickcpu(struct thread *, int); 297 static void sched_balance(void); 298 static int sched_balance_pair(struct tdq *, struct tdq *); 299 static inline struct tdq *sched_setcpu(struct thread *, int, int); 300 static inline void thread_unblock_switch(struct thread *, struct mtx *); 301 static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int); 302 static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS); 303 static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, 304 struct cpu_group *cg, int indent); 305 #endif 306 307 static void sched_setup(void *dummy); 308 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL); 309 310 static void sched_initticks(void *dummy); 311 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, 312 NULL); 313 314 /* 315 * Print the threads waiting on a run-queue. 316 */ 317 static void 318 runq_print(struct runq *rq) 319 { 320 struct rqhead *rqh; 321 struct thread *td; 322 int pri; 323 int j; 324 int i; 325 326 for (i = 0; i < RQB_LEN; i++) { 327 printf("\t\trunq bits %d 0x%zx\n", 328 i, rq->rq_status.rqb_bits[i]); 329 for (j = 0; j < RQB_BPW; j++) 330 if (rq->rq_status.rqb_bits[i] & (1ul << j)) { 331 pri = j + (i << RQB_L2BPW); 332 rqh = &rq->rq_queues[pri]; 333 TAILQ_FOREACH(td, rqh, td_runq) { 334 printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n", 335 td, td->td_name, td->td_priority, 336 td->td_rqindex, pri); 337 } 338 } 339 } 340 } 341 342 /* 343 * Print the status of a per-cpu thread queue. Should be a ddb show cmd. 344 */ 345 void 346 tdq_print(int cpu) 347 { 348 struct tdq *tdq; 349 350 tdq = TDQ_CPU(cpu); 351 352 printf("tdq %d:\n", TDQ_ID(tdq)); 353 printf("\tlock %p\n", TDQ_LOCKPTR(tdq)); 354 printf("\tLock name: %s\n", tdq->tdq_name); 355 printf("\tload: %d\n", tdq->tdq_load); 356 printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt); 357 printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt); 358 printf("\ttimeshare idx: %d\n", tdq->tdq_idx); 359 printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx); 360 printf("\tload transferable: %d\n", tdq->tdq_transferable); 361 printf("\tlowest priority: %d\n", tdq->tdq_lowpri); 362 printf("\trealtime runq:\n"); 363 runq_print(&tdq->tdq_realtime); 364 printf("\ttimeshare runq:\n"); 365 runq_print(&tdq->tdq_timeshare); 366 printf("\tidle runq:\n"); 367 runq_print(&tdq->tdq_idle); 368 } 369 370 static inline int 371 sched_shouldpreempt(int pri, int cpri, int remote) 372 { 373 /* 374 * If the new priority is not better than the current priority there is 375 * nothing to do. 376 */ 377 if (pri >= cpri) 378 return (0); 379 /* 380 * Always preempt idle. 381 */ 382 if (cpri >= PRI_MIN_IDLE) 383 return (1); 384 /* 385 * If preemption is disabled don't preempt others. 386 */ 387 if (preempt_thresh == 0) 388 return (0); 389 /* 390 * Preempt if we exceed the threshold. 391 */ 392 if (pri <= preempt_thresh) 393 return (1); 394 /* 395 * If we're realtime or better and there is timeshare or worse running 396 * preempt only remote processors. 397 */ 398 if (remote && pri <= PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME) 399 return (1); 400 return (0); 401 } 402 403 #define TS_RQ_PPQ (((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS) 404 /* 405 * Add a thread to the actual run-queue. Keeps transferable counts up to 406 * date with what is actually on the run-queue. Selects the correct 407 * queue position for timeshare threads. 408 */ 409 static __inline void 410 tdq_runq_add(struct tdq *tdq, struct thread *td, int flags) 411 { 412 struct td_sched *ts; 413 u_char pri; 414 415 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 416 THREAD_LOCK_ASSERT(td, MA_OWNED); 417 418 pri = td->td_priority; 419 ts = td->td_sched; 420 TD_SET_RUNQ(td); 421 if (THREAD_CAN_MIGRATE(td)) { 422 tdq->tdq_transferable++; 423 ts->ts_flags |= TSF_XFERABLE; 424 } 425 if (pri <= PRI_MAX_REALTIME) { 426 ts->ts_runq = &tdq->tdq_realtime; 427 } else if (pri <= PRI_MAX_TIMESHARE) { 428 ts->ts_runq = &tdq->tdq_timeshare; 429 KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE, 430 ("Invalid priority %d on timeshare runq", pri)); 431 /* 432 * This queue contains only priorities between MIN and MAX 433 * realtime. Use the whole queue to represent these values. 434 */ 435 if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) { 436 pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ; 437 pri = (pri + tdq->tdq_idx) % RQ_NQS; 438 /* 439 * This effectively shortens the queue by one so we 440 * can have a one slot difference between idx and 441 * ridx while we wait for threads to drain. 442 */ 443 if (tdq->tdq_ridx != tdq->tdq_idx && 444 pri == tdq->tdq_ridx) 445 pri = (unsigned char)(pri - 1) % RQ_NQS; 446 } else 447 pri = tdq->tdq_ridx; 448 runq_add_pri(ts->ts_runq, td, pri, flags); 449 return; 450 } else 451 ts->ts_runq = &tdq->tdq_idle; 452 runq_add(ts->ts_runq, td, flags); 453 } 454 455 /* 456 * Remove a thread from a run-queue. This typically happens when a thread 457 * is selected to run. Running threads are not on the queue and the 458 * transferable count does not reflect them. 459 */ 460 static __inline void 461 tdq_runq_rem(struct tdq *tdq, struct thread *td) 462 { 463 struct td_sched *ts; 464 465 ts = td->td_sched; 466 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 467 KASSERT(ts->ts_runq != NULL, 468 ("tdq_runq_remove: thread %p null ts_runq", td)); 469 if (ts->ts_flags & TSF_XFERABLE) { 470 tdq->tdq_transferable--; 471 ts->ts_flags &= ~TSF_XFERABLE; 472 } 473 if (ts->ts_runq == &tdq->tdq_timeshare) { 474 if (tdq->tdq_idx != tdq->tdq_ridx) 475 runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx); 476 else 477 runq_remove_idx(ts->ts_runq, td, NULL); 478 } else 479 runq_remove(ts->ts_runq, td); 480 } 481 482 /* 483 * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load 484 * for this thread to the referenced thread queue. 485 */ 486 static void 487 tdq_load_add(struct tdq *tdq, struct thread *td) 488 { 489 490 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 491 THREAD_LOCK_ASSERT(td, MA_OWNED); 492 493 tdq->tdq_load++; 494 if ((td->td_flags & TDF_NOLOAD) == 0) 495 tdq->tdq_sysload++; 496 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load); 497 } 498 499 /* 500 * Remove the load from a thread that is transitioning to a sleep state or 501 * exiting. 502 */ 503 static void 504 tdq_load_rem(struct tdq *tdq, struct thread *td) 505 { 506 507 THREAD_LOCK_ASSERT(td, MA_OWNED); 508 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 509 KASSERT(tdq->tdq_load != 0, 510 ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq))); 511 512 tdq->tdq_load--; 513 if ((td->td_flags & TDF_NOLOAD) == 0) 514 tdq->tdq_sysload--; 515 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load); 516 } 517 518 /* 519 * Set lowpri to its exact value by searching the run-queue and 520 * evaluating curthread. curthread may be passed as an optimization. 521 */ 522 static void 523 tdq_setlowpri(struct tdq *tdq, struct thread *ctd) 524 { 525 struct thread *td; 526 527 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 528 if (ctd == NULL) 529 ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread; 530 td = tdq_choose(tdq); 531 if (td == NULL || td->td_priority > ctd->td_priority) 532 tdq->tdq_lowpri = ctd->td_priority; 533 else 534 tdq->tdq_lowpri = td->td_priority; 535 } 536 537 #ifdef SMP 538 struct cpu_search { 539 cpuset_t cs_mask; 540 u_int cs_load; 541 u_int cs_cpu; 542 int cs_limit; /* Min priority for low min load for high. */ 543 }; 544 545 #define CPU_SEARCH_LOWEST 0x1 546 #define CPU_SEARCH_HIGHEST 0x2 547 #define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST) 548 549 #define CPUSET_FOREACH(cpu, mask) \ 550 for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++) \ 551 if ((mask) & 1 << (cpu)) 552 553 static __inline int cpu_search(struct cpu_group *cg, struct cpu_search *low, 554 struct cpu_search *high, const int match); 555 int cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low); 556 int cpu_search_highest(struct cpu_group *cg, struct cpu_search *high); 557 int cpu_search_both(struct cpu_group *cg, struct cpu_search *low, 558 struct cpu_search *high); 559 560 /* 561 * This routine compares according to the match argument and should be 562 * reduced in actual instantiations via constant propagation and dead code 563 * elimination. 564 */ 565 static __inline int 566 cpu_compare(int cpu, struct cpu_search *low, struct cpu_search *high, 567 const int match) 568 { 569 struct tdq *tdq; 570 571 tdq = TDQ_CPU(cpu); 572 if (match & CPU_SEARCH_LOWEST) 573 if (CPU_ISSET(cpu, &low->cs_mask) && 574 tdq->tdq_load < low->cs_load && 575 tdq->tdq_lowpri > low->cs_limit) { 576 low->cs_cpu = cpu; 577 low->cs_load = tdq->tdq_load; 578 } 579 if (match & CPU_SEARCH_HIGHEST) 580 if (CPU_ISSET(cpu, &high->cs_mask) && 581 tdq->tdq_load >= high->cs_limit && 582 tdq->tdq_load > high->cs_load && 583 tdq->tdq_transferable) { 584 high->cs_cpu = cpu; 585 high->cs_load = tdq->tdq_load; 586 } 587 return (tdq->tdq_load); 588 } 589 590 /* 591 * Search the tree of cpu_groups for the lowest or highest loaded cpu 592 * according to the match argument. This routine actually compares the 593 * load on all paths through the tree and finds the least loaded cpu on 594 * the least loaded path, which may differ from the least loaded cpu in 595 * the system. This balances work among caches and busses. 596 * 597 * This inline is instantiated in three forms below using constants for the 598 * match argument. It is reduced to the minimum set for each case. It is 599 * also recursive to the depth of the tree. 600 */ 601 static __inline int 602 cpu_search(struct cpu_group *cg, struct cpu_search *low, 603 struct cpu_search *high, const int match) 604 { 605 int total; 606 607 total = 0; 608 if (cg->cg_children) { 609 struct cpu_search lgroup; 610 struct cpu_search hgroup; 611 struct cpu_group *child; 612 u_int lload; 613 int hload; 614 int load; 615 int i; 616 617 lload = -1; 618 hload = -1; 619 for (i = 0; i < cg->cg_children; i++) { 620 child = &cg->cg_child[i]; 621 if (match & CPU_SEARCH_LOWEST) { 622 lgroup = *low; 623 lgroup.cs_load = -1; 624 } 625 if (match & CPU_SEARCH_HIGHEST) { 626 hgroup = *high; 627 lgroup.cs_load = 0; 628 } 629 switch (match) { 630 case CPU_SEARCH_LOWEST: 631 load = cpu_search_lowest(child, &lgroup); 632 break; 633 case CPU_SEARCH_HIGHEST: 634 load = cpu_search_highest(child, &hgroup); 635 break; 636 case CPU_SEARCH_BOTH: 637 load = cpu_search_both(child, &lgroup, &hgroup); 638 break; 639 } 640 total += load; 641 if (match & CPU_SEARCH_LOWEST) 642 if (load < lload || low->cs_cpu == -1) { 643 *low = lgroup; 644 lload = load; 645 } 646 if (match & CPU_SEARCH_HIGHEST) 647 if (load > hload || high->cs_cpu == -1) { 648 hload = load; 649 *high = hgroup; 650 } 651 } 652 } else { 653 int cpu; 654 655 CPUSET_FOREACH(cpu, cg->cg_mask) 656 total += cpu_compare(cpu, low, high, match); 657 } 658 return (total); 659 } 660 661 /* 662 * cpu_search instantiations must pass constants to maintain the inline 663 * optimization. 664 */ 665 int 666 cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low) 667 { 668 return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST); 669 } 670 671 int 672 cpu_search_highest(struct cpu_group *cg, struct cpu_search *high) 673 { 674 return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST); 675 } 676 677 int 678 cpu_search_both(struct cpu_group *cg, struct cpu_search *low, 679 struct cpu_search *high) 680 { 681 return cpu_search(cg, low, high, CPU_SEARCH_BOTH); 682 } 683 684 /* 685 * Find the cpu with the least load via the least loaded path that has a 686 * lowpri greater than pri pri. A pri of -1 indicates any priority is 687 * acceptable. 688 */ 689 static inline int 690 sched_lowest(struct cpu_group *cg, cpuset_t mask, int pri) 691 { 692 struct cpu_search low; 693 694 low.cs_cpu = -1; 695 low.cs_load = -1; 696 low.cs_mask = mask; 697 low.cs_limit = pri; 698 cpu_search_lowest(cg, &low); 699 return low.cs_cpu; 700 } 701 702 /* 703 * Find the cpu with the highest load via the highest loaded path. 704 */ 705 static inline int 706 sched_highest(struct cpu_group *cg, cpuset_t mask, int minload) 707 { 708 struct cpu_search high; 709 710 high.cs_cpu = -1; 711 high.cs_load = 0; 712 high.cs_mask = mask; 713 high.cs_limit = minload; 714 cpu_search_highest(cg, &high); 715 return high.cs_cpu; 716 } 717 718 /* 719 * Simultaneously find the highest and lowest loaded cpu reachable via 720 * cg. 721 */ 722 static inline void 723 sched_both(struct cpu_group *cg, cpuset_t mask, int *lowcpu, int *highcpu) 724 { 725 struct cpu_search high; 726 struct cpu_search low; 727 728 low.cs_cpu = -1; 729 low.cs_limit = -1; 730 low.cs_load = -1; 731 low.cs_mask = mask; 732 high.cs_load = 0; 733 high.cs_cpu = -1; 734 high.cs_limit = -1; 735 high.cs_mask = mask; 736 cpu_search_both(cg, &low, &high); 737 *lowcpu = low.cs_cpu; 738 *highcpu = high.cs_cpu; 739 return; 740 } 741 742 static void 743 sched_balance_group(struct cpu_group *cg) 744 { 745 cpuset_t mask; 746 int high; 747 int low; 748 int i; 749 750 CPU_FILL(&mask); 751 for (;;) { 752 sched_both(cg, mask, &low, &high); 753 if (low == high || low == -1 || high == -1) 754 break; 755 if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low))) 756 break; 757 /* 758 * If we failed to move any threads determine which cpu 759 * to kick out of the set and try again. 760 */ 761 if (TDQ_CPU(high)->tdq_transferable == 0) 762 CPU_CLR(high, &mask); 763 else 764 CPU_CLR(low, &mask); 765 } 766 767 for (i = 0; i < cg->cg_children; i++) 768 sched_balance_group(&cg->cg_child[i]); 769 } 770 771 static void 772 sched_balance(void) 773 { 774 struct tdq *tdq; 775 776 /* 777 * Select a random time between .5 * balance_interval and 778 * 1.5 * balance_interval. 779 */ 780 balance_ticks = max(balance_interval / 2, 1); 781 balance_ticks += random() % balance_interval; 782 if (smp_started == 0 || rebalance == 0) 783 return; 784 tdq = TDQ_SELF(); 785 TDQ_UNLOCK(tdq); 786 sched_balance_group(cpu_top); 787 TDQ_LOCK(tdq); 788 } 789 790 /* 791 * Lock two thread queues using their address to maintain lock order. 792 */ 793 static void 794 tdq_lock_pair(struct tdq *one, struct tdq *two) 795 { 796 if (one < two) { 797 TDQ_LOCK(one); 798 TDQ_LOCK_FLAGS(two, MTX_DUPOK); 799 } else { 800 TDQ_LOCK(two); 801 TDQ_LOCK_FLAGS(one, MTX_DUPOK); 802 } 803 } 804 805 /* 806 * Unlock two thread queues. Order is not important here. 807 */ 808 static void 809 tdq_unlock_pair(struct tdq *one, struct tdq *two) 810 { 811 TDQ_UNLOCK(one); 812 TDQ_UNLOCK(two); 813 } 814 815 /* 816 * Transfer load between two imbalanced thread queues. 817 */ 818 static int 819 sched_balance_pair(struct tdq *high, struct tdq *low) 820 { 821 int transferable; 822 int high_load; 823 int low_load; 824 int moved; 825 int move; 826 int diff; 827 int i; 828 829 tdq_lock_pair(high, low); 830 transferable = high->tdq_transferable; 831 high_load = high->tdq_load; 832 low_load = low->tdq_load; 833 moved = 0; 834 /* 835 * Determine what the imbalance is and then adjust that to how many 836 * threads we actually have to give up (transferable). 837 */ 838 if (transferable != 0) { 839 diff = high_load - low_load; 840 move = diff / 2; 841 if (diff & 0x1) 842 move++; 843 move = min(move, transferable); 844 for (i = 0; i < move; i++) 845 moved += tdq_move(high, low); 846 /* 847 * IPI the target cpu to force it to reschedule with the new 848 * workload. 849 */ 850 ipi_cpu(TDQ_ID(low), IPI_PREEMPT); 851 } 852 tdq_unlock_pair(high, low); 853 return (moved); 854 } 855 856 /* 857 * Move a thread from one thread queue to another. 858 */ 859 static int 860 tdq_move(struct tdq *from, struct tdq *to) 861 { 862 struct td_sched *ts; 863 struct thread *td; 864 struct tdq *tdq; 865 int cpu; 866 867 TDQ_LOCK_ASSERT(from, MA_OWNED); 868 TDQ_LOCK_ASSERT(to, MA_OWNED); 869 870 tdq = from; 871 cpu = TDQ_ID(to); 872 td = tdq_steal(tdq, cpu); 873 if (td == NULL) 874 return (0); 875 ts = td->td_sched; 876 /* 877 * Although the run queue is locked the thread may be blocked. Lock 878 * it to clear this and acquire the run-queue lock. 879 */ 880 thread_lock(td); 881 /* Drop recursive lock on from acquired via thread_lock(). */ 882 TDQ_UNLOCK(from); 883 sched_rem(td); 884 ts->ts_cpu = cpu; 885 td->td_lock = TDQ_LOCKPTR(to); 886 tdq_add(to, td, SRQ_YIELDING); 887 return (1); 888 } 889 890 /* 891 * This tdq has idled. Try to steal a thread from another cpu and switch 892 * to it. 893 */ 894 static int 895 tdq_idled(struct tdq *tdq) 896 { 897 struct cpu_group *cg; 898 struct tdq *steal; 899 cpuset_t mask; 900 int thresh; 901 int cpu; 902 903 if (smp_started == 0 || steal_idle == 0) 904 return (1); 905 CPU_FILL(&mask); 906 CPU_CLR(PCPU_GET(cpuid), &mask); 907 /* We don't want to be preempted while we're iterating. */ 908 spinlock_enter(); 909 for (cg = tdq->tdq_cg; cg != NULL; ) { 910 if ((cg->cg_flags & CG_FLAG_THREAD) == 0) 911 thresh = steal_thresh; 912 else 913 thresh = 1; 914 cpu = sched_highest(cg, mask, thresh); 915 if (cpu == -1) { 916 cg = cg->cg_parent; 917 continue; 918 } 919 steal = TDQ_CPU(cpu); 920 CPU_CLR(cpu, &mask); 921 tdq_lock_pair(tdq, steal); 922 if (steal->tdq_load < thresh || steal->tdq_transferable == 0) { 923 tdq_unlock_pair(tdq, steal); 924 continue; 925 } 926 /* 927 * If a thread was added while interrupts were disabled don't 928 * steal one here. If we fail to acquire one due to affinity 929 * restrictions loop again with this cpu removed from the 930 * set. 931 */ 932 if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) { 933 tdq_unlock_pair(tdq, steal); 934 continue; 935 } 936 spinlock_exit(); 937 TDQ_UNLOCK(steal); 938 mi_switch(SW_VOL | SWT_IDLE, NULL); 939 thread_unlock(curthread); 940 941 return (0); 942 } 943 spinlock_exit(); 944 return (1); 945 } 946 947 /* 948 * Notify a remote cpu of new work. Sends an IPI if criteria are met. 949 */ 950 static void 951 tdq_notify(struct tdq *tdq, struct thread *td) 952 { 953 struct thread *ctd; 954 int pri; 955 int cpu; 956 957 if (tdq->tdq_ipipending) 958 return; 959 cpu = td->td_sched->ts_cpu; 960 pri = td->td_priority; 961 ctd = pcpu_find(cpu)->pc_curthread; 962 if (!sched_shouldpreempt(pri, ctd->td_priority, 1)) 963 return; 964 if (TD_IS_IDLETHREAD(ctd)) { 965 /* 966 * If the MD code has an idle wakeup routine try that before 967 * falling back to IPI. 968 */ 969 if (cpu_idle_wakeup(cpu)) 970 return; 971 } 972 tdq->tdq_ipipending = 1; 973 ipi_cpu(cpu, IPI_PREEMPT); 974 } 975 976 /* 977 * Steals load from a timeshare queue. Honors the rotating queue head 978 * index. 979 */ 980 static struct thread * 981 runq_steal_from(struct runq *rq, int cpu, u_char start) 982 { 983 struct rqbits *rqb; 984 struct rqhead *rqh; 985 struct thread *td; 986 int first; 987 int bit; 988 int pri; 989 int i; 990 991 rqb = &rq->rq_status; 992 bit = start & (RQB_BPW -1); 993 pri = 0; 994 first = 0; 995 again: 996 for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) { 997 if (rqb->rqb_bits[i] == 0) 998 continue; 999 if (bit != 0) { 1000 for (pri = bit; pri < RQB_BPW; pri++) 1001 if (rqb->rqb_bits[i] & (1ul << pri)) 1002 break; 1003 if (pri >= RQB_BPW) 1004 continue; 1005 } else 1006 pri = RQB_FFS(rqb->rqb_bits[i]); 1007 pri += (i << RQB_L2BPW); 1008 rqh = &rq->rq_queues[pri]; 1009 TAILQ_FOREACH(td, rqh, td_runq) { 1010 if (first && THREAD_CAN_MIGRATE(td) && 1011 THREAD_CAN_SCHED(td, cpu)) 1012 return (td); 1013 first = 1; 1014 } 1015 } 1016 if (start != 0) { 1017 start = 0; 1018 goto again; 1019 } 1020 1021 return (NULL); 1022 } 1023 1024 /* 1025 * Steals load from a standard linear queue. 1026 */ 1027 static struct thread * 1028 runq_steal(struct runq *rq, int cpu) 1029 { 1030 struct rqhead *rqh; 1031 struct rqbits *rqb; 1032 struct thread *td; 1033 int word; 1034 int bit; 1035 1036 rqb = &rq->rq_status; 1037 for (word = 0; word < RQB_LEN; word++) { 1038 if (rqb->rqb_bits[word] == 0) 1039 continue; 1040 for (bit = 0; bit < RQB_BPW; bit++) { 1041 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) 1042 continue; 1043 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; 1044 TAILQ_FOREACH(td, rqh, td_runq) 1045 if (THREAD_CAN_MIGRATE(td) && 1046 THREAD_CAN_SCHED(td, cpu)) 1047 return (td); 1048 } 1049 } 1050 return (NULL); 1051 } 1052 1053 /* 1054 * Attempt to steal a thread in priority order from a thread queue. 1055 */ 1056 static struct thread * 1057 tdq_steal(struct tdq *tdq, int cpu) 1058 { 1059 struct thread *td; 1060 1061 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1062 if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL) 1063 return (td); 1064 if ((td = runq_steal_from(&tdq->tdq_timeshare, 1065 cpu, tdq->tdq_ridx)) != NULL) 1066 return (td); 1067 return (runq_steal(&tdq->tdq_idle, cpu)); 1068 } 1069 1070 /* 1071 * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the 1072 * current lock and returns with the assigned queue locked. 1073 */ 1074 static inline struct tdq * 1075 sched_setcpu(struct thread *td, int cpu, int flags) 1076 { 1077 1078 struct tdq *tdq; 1079 1080 THREAD_LOCK_ASSERT(td, MA_OWNED); 1081 tdq = TDQ_CPU(cpu); 1082 td->td_sched->ts_cpu = cpu; 1083 /* 1084 * If the lock matches just return the queue. 1085 */ 1086 if (td->td_lock == TDQ_LOCKPTR(tdq)) 1087 return (tdq); 1088 #ifdef notyet 1089 /* 1090 * If the thread isn't running its lockptr is a 1091 * turnstile or a sleepqueue. We can just lock_set without 1092 * blocking. 1093 */ 1094 if (TD_CAN_RUN(td)) { 1095 TDQ_LOCK(tdq); 1096 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 1097 return (tdq); 1098 } 1099 #endif 1100 /* 1101 * The hard case, migration, we need to block the thread first to 1102 * prevent order reversals with other cpus locks. 1103 */ 1104 spinlock_enter(); 1105 thread_lock_block(td); 1106 TDQ_LOCK(tdq); 1107 thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); 1108 spinlock_exit(); 1109 return (tdq); 1110 } 1111 1112 SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding"); 1113 SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity"); 1114 SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity"); 1115 SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load"); 1116 SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu"); 1117 SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration"); 1118 1119 static int 1120 sched_pickcpu(struct thread *td, int flags) 1121 { 1122 struct cpu_group *cg; 1123 struct td_sched *ts; 1124 struct tdq *tdq; 1125 cpuset_t mask; 1126 int self; 1127 int pri; 1128 int cpu; 1129 1130 self = PCPU_GET(cpuid); 1131 ts = td->td_sched; 1132 if (smp_started == 0) 1133 return (self); 1134 /* 1135 * Don't migrate a running thread from sched_switch(). 1136 */ 1137 if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td)) 1138 return (ts->ts_cpu); 1139 /* 1140 * Prefer to run interrupt threads on the processors that generate 1141 * the interrupt. 1142 */ 1143 if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) && 1144 curthread->td_intr_nesting_level && ts->ts_cpu != self) { 1145 SCHED_STAT_INC(pickcpu_intrbind); 1146 ts->ts_cpu = self; 1147 } 1148 /* 1149 * If the thread can run on the last cpu and the affinity has not 1150 * expired or it is idle run it there. 1151 */ 1152 pri = td->td_priority; 1153 tdq = TDQ_CPU(ts->ts_cpu); 1154 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) { 1155 if (tdq->tdq_lowpri > PRI_MIN_IDLE) { 1156 SCHED_STAT_INC(pickcpu_idle_affinity); 1157 return (ts->ts_cpu); 1158 } 1159 if (SCHED_AFFINITY(ts, CG_SHARE_L2) && tdq->tdq_lowpri > pri) { 1160 SCHED_STAT_INC(pickcpu_affinity); 1161 return (ts->ts_cpu); 1162 } 1163 } 1164 /* 1165 * Search for the highest level in the tree that still has affinity. 1166 */ 1167 cg = NULL; 1168 for (cg = tdq->tdq_cg; cg != NULL; cg = cg->cg_parent) 1169 if (SCHED_AFFINITY(ts, cg->cg_level)) 1170 break; 1171 cpu = -1; 1172 mask = td->td_cpuset->cs_mask; 1173 if (cg) 1174 cpu = sched_lowest(cg, mask, pri); 1175 if (cpu == -1) 1176 cpu = sched_lowest(cpu_top, mask, -1); 1177 /* 1178 * Compare the lowest loaded cpu to current cpu. 1179 */ 1180 if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri && 1181 TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE) { 1182 SCHED_STAT_INC(pickcpu_local); 1183 cpu = self; 1184 } else 1185 SCHED_STAT_INC(pickcpu_lowest); 1186 if (cpu != ts->ts_cpu) 1187 SCHED_STAT_INC(pickcpu_migration); 1188 KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu.")); 1189 return (cpu); 1190 } 1191 #endif 1192 1193 /* 1194 * Pick the highest priority task we have and return it. 1195 */ 1196 static struct thread * 1197 tdq_choose(struct tdq *tdq) 1198 { 1199 struct thread *td; 1200 1201 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1202 td = runq_choose(&tdq->tdq_realtime); 1203 if (td != NULL) 1204 return (td); 1205 td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); 1206 if (td != NULL) { 1207 KASSERT(td->td_priority >= PRI_MIN_TIMESHARE, 1208 ("tdq_choose: Invalid priority on timeshare queue %d", 1209 td->td_priority)); 1210 return (td); 1211 } 1212 td = runq_choose(&tdq->tdq_idle); 1213 if (td != NULL) { 1214 KASSERT(td->td_priority >= PRI_MIN_IDLE, 1215 ("tdq_choose: Invalid priority on idle queue %d", 1216 td->td_priority)); 1217 return (td); 1218 } 1219 1220 return (NULL); 1221 } 1222 1223 /* 1224 * Initialize a thread queue. 1225 */ 1226 static void 1227 tdq_setup(struct tdq *tdq) 1228 { 1229 1230 if (bootverbose) 1231 printf("ULE: setup cpu %d\n", TDQ_ID(tdq)); 1232 runq_init(&tdq->tdq_realtime); 1233 runq_init(&tdq->tdq_timeshare); 1234 runq_init(&tdq->tdq_idle); 1235 snprintf(tdq->tdq_name, sizeof(tdq->tdq_name), 1236 "sched lock %d", (int)TDQ_ID(tdq)); 1237 mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock", 1238 MTX_SPIN | MTX_RECURSE); 1239 #ifdef KTR 1240 snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname), 1241 "CPU %d load", (int)TDQ_ID(tdq)); 1242 #endif 1243 } 1244 1245 #ifdef SMP 1246 static void 1247 sched_setup_smp(void) 1248 { 1249 struct tdq *tdq; 1250 int i; 1251 1252 cpu_top = smp_topo(); 1253 CPU_FOREACH(i) { 1254 tdq = TDQ_CPU(i); 1255 tdq_setup(tdq); 1256 tdq->tdq_cg = smp_topo_find(cpu_top, i); 1257 if (tdq->tdq_cg == NULL) 1258 panic("Can't find cpu group for %d\n", i); 1259 } 1260 balance_tdq = TDQ_SELF(); 1261 sched_balance(); 1262 } 1263 #endif 1264 1265 /* 1266 * Setup the thread queues and initialize the topology based on MD 1267 * information. 1268 */ 1269 static void 1270 sched_setup(void *dummy) 1271 { 1272 struct tdq *tdq; 1273 1274 tdq = TDQ_SELF(); 1275 #ifdef SMP 1276 sched_setup_smp(); 1277 #else 1278 tdq_setup(tdq); 1279 #endif 1280 /* 1281 * To avoid divide-by-zero, we set realstathz a dummy value 1282 * in case which sched_clock() called before sched_initticks(). 1283 */ 1284 realstathz = hz; 1285 sched_slice = (realstathz/10); /* ~100ms */ 1286 tickincr = 1 << SCHED_TICK_SHIFT; 1287 1288 /* Add thread0's load since it's running. */ 1289 TDQ_LOCK(tdq); 1290 thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1291 tdq_load_add(tdq, &thread0); 1292 tdq->tdq_lowpri = thread0.td_priority; 1293 TDQ_UNLOCK(tdq); 1294 } 1295 1296 /* 1297 * This routine determines the tickincr after stathz and hz are setup. 1298 */ 1299 /* ARGSUSED */ 1300 static void 1301 sched_initticks(void *dummy) 1302 { 1303 int incr; 1304 1305 realstathz = stathz ? stathz : hz; 1306 sched_slice = (realstathz/10); /* ~100ms */ 1307 1308 /* 1309 * tickincr is shifted out by 10 to avoid rounding errors due to 1310 * hz not being evenly divisible by stathz on all platforms. 1311 */ 1312 incr = (hz << SCHED_TICK_SHIFT) / realstathz; 1313 /* 1314 * This does not work for values of stathz that are more than 1315 * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen. 1316 */ 1317 if (incr == 0) 1318 incr = 1; 1319 tickincr = incr; 1320 #ifdef SMP 1321 /* 1322 * Set the default balance interval now that we know 1323 * what realstathz is. 1324 */ 1325 balance_interval = realstathz; 1326 /* 1327 * Set steal thresh to roughly log2(mp_ncpu) but no greater than 4. 1328 * This prevents excess thrashing on large machines and excess idle 1329 * on smaller machines. 1330 */ 1331 steal_thresh = min(fls(mp_ncpus) - 1, 3); 1332 affinity = SCHED_AFFINITY_DEFAULT; 1333 #endif 1334 } 1335 1336 1337 /* 1338 * This is the core of the interactivity algorithm. Determines a score based 1339 * on past behavior. It is the ratio of sleep time to run time scaled to 1340 * a [0, 100] integer. This is the voluntary sleep time of a process, which 1341 * differs from the cpu usage because it does not account for time spent 1342 * waiting on a run-queue. Would be prettier if we had floating point. 1343 */ 1344 static int 1345 sched_interact_score(struct thread *td) 1346 { 1347 struct td_sched *ts; 1348 int div; 1349 1350 ts = td->td_sched; 1351 /* 1352 * The score is only needed if this is likely to be an interactive 1353 * task. Don't go through the expense of computing it if there's 1354 * no chance. 1355 */ 1356 if (sched_interact <= SCHED_INTERACT_HALF && 1357 ts->ts_runtime >= ts->ts_slptime) 1358 return (SCHED_INTERACT_HALF); 1359 1360 if (ts->ts_runtime > ts->ts_slptime) { 1361 div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF); 1362 return (SCHED_INTERACT_HALF + 1363 (SCHED_INTERACT_HALF - (ts->ts_slptime / div))); 1364 } 1365 if (ts->ts_slptime > ts->ts_runtime) { 1366 div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF); 1367 return (ts->ts_runtime / div); 1368 } 1369 /* runtime == slptime */ 1370 if (ts->ts_runtime) 1371 return (SCHED_INTERACT_HALF); 1372 1373 /* 1374 * This can happen if slptime and runtime are 0. 1375 */ 1376 return (0); 1377 1378 } 1379 1380 /* 1381 * Scale the scheduling priority according to the "interactivity" of this 1382 * process. 1383 */ 1384 static void 1385 sched_priority(struct thread *td) 1386 { 1387 int score; 1388 int pri; 1389 1390 if (td->td_pri_class != PRI_TIMESHARE) 1391 return; 1392 /* 1393 * If the score is interactive we place the thread in the realtime 1394 * queue with a priority that is less than kernel and interrupt 1395 * priorities. These threads are not subject to nice restrictions. 1396 * 1397 * Scores greater than this are placed on the normal timeshare queue 1398 * where the priority is partially decided by the most recent cpu 1399 * utilization and the rest is decided by nice value. 1400 * 1401 * The nice value of the process has a linear effect on the calculated 1402 * score. Negative nice values make it easier for a thread to be 1403 * considered interactive. 1404 */ 1405 score = imax(0, sched_interact_score(td) + td->td_proc->p_nice); 1406 if (score < sched_interact) { 1407 pri = PRI_MIN_REALTIME; 1408 pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME) / sched_interact) 1409 * score; 1410 KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME, 1411 ("sched_priority: invalid interactive priority %d score %d", 1412 pri, score)); 1413 } else { 1414 pri = SCHED_PRI_MIN; 1415 if (td->td_sched->ts_ticks) 1416 pri += SCHED_PRI_TICKS(td->td_sched); 1417 pri += SCHED_PRI_NICE(td->td_proc->p_nice); 1418 KASSERT(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE, 1419 ("sched_priority: invalid priority %d: nice %d, " 1420 "ticks %d ftick %d ltick %d tick pri %d", 1421 pri, td->td_proc->p_nice, td->td_sched->ts_ticks, 1422 td->td_sched->ts_ftick, td->td_sched->ts_ltick, 1423 SCHED_PRI_TICKS(td->td_sched))); 1424 } 1425 sched_user_prio(td, pri); 1426 1427 return; 1428 } 1429 1430 /* 1431 * This routine enforces a maximum limit on the amount of scheduling history 1432 * kept. It is called after either the slptime or runtime is adjusted. This 1433 * function is ugly due to integer math. 1434 */ 1435 static void 1436 sched_interact_update(struct thread *td) 1437 { 1438 struct td_sched *ts; 1439 u_int sum; 1440 1441 ts = td->td_sched; 1442 sum = ts->ts_runtime + ts->ts_slptime; 1443 if (sum < SCHED_SLP_RUN_MAX) 1444 return; 1445 /* 1446 * This only happens from two places: 1447 * 1) We have added an unusual amount of run time from fork_exit. 1448 * 2) We have added an unusual amount of sleep time from sched_sleep(). 1449 */ 1450 if (sum > SCHED_SLP_RUN_MAX * 2) { 1451 if (ts->ts_runtime > ts->ts_slptime) { 1452 ts->ts_runtime = SCHED_SLP_RUN_MAX; 1453 ts->ts_slptime = 1; 1454 } else { 1455 ts->ts_slptime = SCHED_SLP_RUN_MAX; 1456 ts->ts_runtime = 1; 1457 } 1458 return; 1459 } 1460 /* 1461 * If we have exceeded by more than 1/5th then the algorithm below 1462 * will not bring us back into range. Dividing by two here forces 1463 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] 1464 */ 1465 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { 1466 ts->ts_runtime /= 2; 1467 ts->ts_slptime /= 2; 1468 return; 1469 } 1470 ts->ts_runtime = (ts->ts_runtime / 5) * 4; 1471 ts->ts_slptime = (ts->ts_slptime / 5) * 4; 1472 } 1473 1474 /* 1475 * Scale back the interactivity history when a child thread is created. The 1476 * history is inherited from the parent but the thread may behave totally 1477 * differently. For example, a shell spawning a compiler process. We want 1478 * to learn that the compiler is behaving badly very quickly. 1479 */ 1480 static void 1481 sched_interact_fork(struct thread *td) 1482 { 1483 int ratio; 1484 int sum; 1485 1486 sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime; 1487 if (sum > SCHED_SLP_RUN_FORK) { 1488 ratio = sum / SCHED_SLP_RUN_FORK; 1489 td->td_sched->ts_runtime /= ratio; 1490 td->td_sched->ts_slptime /= ratio; 1491 } 1492 } 1493 1494 /* 1495 * Called from proc0_init() to setup the scheduler fields. 1496 */ 1497 void 1498 schedinit(void) 1499 { 1500 1501 /* 1502 * Set up the scheduler specific parts of proc0. 1503 */ 1504 proc0.p_sched = NULL; /* XXX */ 1505 thread0.td_sched = &td_sched0; 1506 td_sched0.ts_ltick = ticks; 1507 td_sched0.ts_ftick = ticks; 1508 td_sched0.ts_slice = sched_slice; 1509 } 1510 1511 /* 1512 * This is only somewhat accurate since given many processes of the same 1513 * priority they will switch when their slices run out, which will be 1514 * at most sched_slice stathz ticks. 1515 */ 1516 int 1517 sched_rr_interval(void) 1518 { 1519 1520 /* Convert sched_slice to hz */ 1521 return (hz/(realstathz/sched_slice)); 1522 } 1523 1524 /* 1525 * Update the percent cpu tracking information when it is requested or 1526 * the total history exceeds the maximum. We keep a sliding history of 1527 * tick counts that slowly decays. This is less precise than the 4BSD 1528 * mechanism since it happens with less regular and frequent events. 1529 */ 1530 static void 1531 sched_pctcpu_update(struct td_sched *ts) 1532 { 1533 1534 if (ts->ts_ticks == 0) 1535 return; 1536 if (ticks - (hz / 10) < ts->ts_ltick && 1537 SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX) 1538 return; 1539 /* 1540 * Adjust counters and watermark for pctcpu calc. 1541 */ 1542 if (ts->ts_ltick > ticks - SCHED_TICK_TARG) 1543 ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) * 1544 SCHED_TICK_TARG; 1545 else 1546 ts->ts_ticks = 0; 1547 ts->ts_ltick = ticks; 1548 ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG; 1549 } 1550 1551 /* 1552 * Adjust the priority of a thread. Move it to the appropriate run-queue 1553 * if necessary. This is the back-end for several priority related 1554 * functions. 1555 */ 1556 static void 1557 sched_thread_priority(struct thread *td, u_char prio) 1558 { 1559 struct td_sched *ts; 1560 struct tdq *tdq; 1561 int oldpri; 1562 1563 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio", 1564 "prio:%d", td->td_priority, "new prio:%d", prio, 1565 KTR_ATTR_LINKED, sched_tdname(curthread)); 1566 if (td != curthread && prio > td->td_priority) { 1567 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread), 1568 "lend prio", "prio:%d", td->td_priority, "new prio:%d", 1569 prio, KTR_ATTR_LINKED, sched_tdname(td)); 1570 } 1571 ts = td->td_sched; 1572 THREAD_LOCK_ASSERT(td, MA_OWNED); 1573 if (td->td_priority == prio) 1574 return; 1575 /* 1576 * If the priority has been elevated due to priority 1577 * propagation, we may have to move ourselves to a new 1578 * queue. This could be optimized to not re-add in some 1579 * cases. 1580 */ 1581 if (TD_ON_RUNQ(td) && prio < td->td_priority) { 1582 sched_rem(td); 1583 td->td_priority = prio; 1584 sched_add(td, SRQ_BORROWING); 1585 return; 1586 } 1587 /* 1588 * If the thread is currently running we may have to adjust the lowpri 1589 * information so other cpus are aware of our current priority. 1590 */ 1591 if (TD_IS_RUNNING(td)) { 1592 tdq = TDQ_CPU(ts->ts_cpu); 1593 oldpri = td->td_priority; 1594 td->td_priority = prio; 1595 if (prio < tdq->tdq_lowpri) 1596 tdq->tdq_lowpri = prio; 1597 else if (tdq->tdq_lowpri == oldpri) 1598 tdq_setlowpri(tdq, td); 1599 return; 1600 } 1601 td->td_priority = prio; 1602 } 1603 1604 /* 1605 * Update a thread's priority when it is lent another thread's 1606 * priority. 1607 */ 1608 void 1609 sched_lend_prio(struct thread *td, u_char prio) 1610 { 1611 1612 td->td_flags |= TDF_BORROWING; 1613 sched_thread_priority(td, prio); 1614 } 1615 1616 /* 1617 * Restore a thread's priority when priority propagation is 1618 * over. The prio argument is the minimum priority the thread 1619 * needs to have to satisfy other possible priority lending 1620 * requests. If the thread's regular priority is less 1621 * important than prio, the thread will keep a priority boost 1622 * of prio. 1623 */ 1624 void 1625 sched_unlend_prio(struct thread *td, u_char prio) 1626 { 1627 u_char base_pri; 1628 1629 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 1630 td->td_base_pri <= PRI_MAX_TIMESHARE) 1631 base_pri = td->td_user_pri; 1632 else 1633 base_pri = td->td_base_pri; 1634 if (prio >= base_pri) { 1635 td->td_flags &= ~TDF_BORROWING; 1636 sched_thread_priority(td, base_pri); 1637 } else 1638 sched_lend_prio(td, prio); 1639 } 1640 1641 /* 1642 * Standard entry for setting the priority to an absolute value. 1643 */ 1644 void 1645 sched_prio(struct thread *td, u_char prio) 1646 { 1647 u_char oldprio; 1648 1649 /* First, update the base priority. */ 1650 td->td_base_pri = prio; 1651 1652 /* 1653 * If the thread is borrowing another thread's priority, don't 1654 * ever lower the priority. 1655 */ 1656 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 1657 return; 1658 1659 /* Change the real priority. */ 1660 oldprio = td->td_priority; 1661 sched_thread_priority(td, prio); 1662 1663 /* 1664 * If the thread is on a turnstile, then let the turnstile update 1665 * its state. 1666 */ 1667 if (TD_ON_LOCK(td) && oldprio != prio) 1668 turnstile_adjust(td, oldprio); 1669 } 1670 1671 /* 1672 * Set the base user priority, does not effect current running priority. 1673 */ 1674 void 1675 sched_user_prio(struct thread *td, u_char prio) 1676 { 1677 u_char oldprio; 1678 1679 td->td_base_user_pri = prio; 1680 if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio) 1681 return; 1682 oldprio = td->td_user_pri; 1683 td->td_user_pri = prio; 1684 } 1685 1686 void 1687 sched_lend_user_prio(struct thread *td, u_char prio) 1688 { 1689 u_char oldprio; 1690 1691 THREAD_LOCK_ASSERT(td, MA_OWNED); 1692 td->td_flags |= TDF_UBORROWING; 1693 oldprio = td->td_user_pri; 1694 td->td_user_pri = prio; 1695 } 1696 1697 void 1698 sched_unlend_user_prio(struct thread *td, u_char prio) 1699 { 1700 u_char base_pri; 1701 1702 THREAD_LOCK_ASSERT(td, MA_OWNED); 1703 base_pri = td->td_base_user_pri; 1704 if (prio >= base_pri) { 1705 td->td_flags &= ~TDF_UBORROWING; 1706 sched_user_prio(td, base_pri); 1707 } else { 1708 sched_lend_user_prio(td, prio); 1709 } 1710 } 1711 1712 /* 1713 * Handle migration from sched_switch(). This happens only for 1714 * cpu binding. 1715 */ 1716 static struct mtx * 1717 sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) 1718 { 1719 struct tdq *tdn; 1720 1721 tdn = TDQ_CPU(td->td_sched->ts_cpu); 1722 #ifdef SMP 1723 tdq_load_rem(tdq, td); 1724 /* 1725 * Do the lock dance required to avoid LOR. We grab an extra 1726 * spinlock nesting to prevent preemption while we're 1727 * not holding either run-queue lock. 1728 */ 1729 spinlock_enter(); 1730 thread_lock_block(td); /* This releases the lock on tdq. */ 1731 1732 /* 1733 * Acquire both run-queue locks before placing the thread on the new 1734 * run-queue to avoid deadlocks created by placing a thread with a 1735 * blocked lock on the run-queue of a remote processor. The deadlock 1736 * occurs when a third processor attempts to lock the two queues in 1737 * question while the target processor is spinning with its own 1738 * run-queue lock held while waiting for the blocked lock to clear. 1739 */ 1740 tdq_lock_pair(tdn, tdq); 1741 tdq_add(tdn, td, flags); 1742 tdq_notify(tdn, td); 1743 TDQ_UNLOCK(tdn); 1744 spinlock_exit(); 1745 #endif 1746 return (TDQ_LOCKPTR(tdn)); 1747 } 1748 1749 /* 1750 * Variadic version of thread_lock_unblock() that does not assume td_lock 1751 * is blocked. 1752 */ 1753 static inline void 1754 thread_unblock_switch(struct thread *td, struct mtx *mtx) 1755 { 1756 atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock, 1757 (uintptr_t)mtx); 1758 } 1759 1760 /* 1761 * Switch threads. This function has to handle threads coming in while 1762 * blocked for some reason, running, or idle. It also must deal with 1763 * migrating a thread from one queue to another as running threads may 1764 * be assigned elsewhere via binding. 1765 */ 1766 void 1767 sched_switch(struct thread *td, struct thread *newtd, int flags) 1768 { 1769 struct tdq *tdq; 1770 struct td_sched *ts; 1771 struct mtx *mtx; 1772 int srqflag; 1773 int cpuid; 1774 1775 THREAD_LOCK_ASSERT(td, MA_OWNED); 1776 KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument")); 1777 1778 cpuid = PCPU_GET(cpuid); 1779 tdq = TDQ_CPU(cpuid); 1780 ts = td->td_sched; 1781 mtx = td->td_lock; 1782 ts->ts_rltick = ticks; 1783 td->td_lastcpu = td->td_oncpu; 1784 td->td_oncpu = NOCPU; 1785 td->td_flags &= ~TDF_NEEDRESCHED; 1786 td->td_owepreempt = 0; 1787 tdq->tdq_switchcnt++; 1788 /* 1789 * The lock pointer in an idle thread should never change. Reset it 1790 * to CAN_RUN as well. 1791 */ 1792 if (TD_IS_IDLETHREAD(td)) { 1793 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1794 TD_SET_CAN_RUN(td); 1795 } else if (TD_IS_RUNNING(td)) { 1796 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1797 srqflag = (flags & SW_PREEMPT) ? 1798 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1799 SRQ_OURSELF|SRQ_YIELDING; 1800 if (ts->ts_cpu == cpuid) 1801 tdq_runq_add(tdq, td, srqflag); 1802 else 1803 mtx = sched_switch_migrate(tdq, td, srqflag); 1804 } else { 1805 /* This thread must be going to sleep. */ 1806 TDQ_LOCK(tdq); 1807 mtx = thread_lock_block(td); 1808 tdq_load_rem(tdq, td); 1809 } 1810 /* 1811 * We enter here with the thread blocked and assigned to the 1812 * appropriate cpu run-queue or sleep-queue and with the current 1813 * thread-queue locked. 1814 */ 1815 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 1816 newtd = choosethread(); 1817 /* 1818 * Call the MD code to switch contexts if necessary. 1819 */ 1820 if (td != newtd) { 1821 #ifdef HWPMC_HOOKS 1822 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1823 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1824 #endif 1825 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 1826 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 1827 1828 #ifdef KDTRACE_HOOKS 1829 /* 1830 * If DTrace has set the active vtime enum to anything 1831 * other than INACTIVE (0), then it should have set the 1832 * function to call. 1833 */ 1834 if (dtrace_vtime_active) 1835 (*dtrace_vtime_switch_func)(newtd); 1836 #endif 1837 1838 cpu_switch(td, newtd, mtx); 1839 /* 1840 * We may return from cpu_switch on a different cpu. However, 1841 * we always return with td_lock pointing to the current cpu's 1842 * run queue lock. 1843 */ 1844 cpuid = PCPU_GET(cpuid); 1845 tdq = TDQ_CPU(cpuid); 1846 lock_profile_obtain_lock_success( 1847 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 1848 #ifdef HWPMC_HOOKS 1849 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1850 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1851 #endif 1852 } else 1853 thread_unblock_switch(td, mtx); 1854 /* 1855 * Assert that all went well and return. 1856 */ 1857 TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED); 1858 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1859 td->td_oncpu = cpuid; 1860 } 1861 1862 /* 1863 * Adjust thread priorities as a result of a nice request. 1864 */ 1865 void 1866 sched_nice(struct proc *p, int nice) 1867 { 1868 struct thread *td; 1869 1870 PROC_LOCK_ASSERT(p, MA_OWNED); 1871 1872 p->p_nice = nice; 1873 FOREACH_THREAD_IN_PROC(p, td) { 1874 thread_lock(td); 1875 sched_priority(td); 1876 sched_prio(td, td->td_base_user_pri); 1877 thread_unlock(td); 1878 } 1879 } 1880 1881 /* 1882 * Record the sleep time for the interactivity scorer. 1883 */ 1884 void 1885 sched_sleep(struct thread *td, int prio) 1886 { 1887 1888 THREAD_LOCK_ASSERT(td, MA_OWNED); 1889 1890 td->td_slptick = ticks; 1891 if (TD_IS_SUSPENDED(td) || prio >= PSOCK) 1892 td->td_flags |= TDF_CANSWAP; 1893 if (static_boost == 1 && prio) 1894 sched_prio(td, prio); 1895 else if (static_boost && td->td_priority > static_boost) 1896 sched_prio(td, static_boost); 1897 } 1898 1899 /* 1900 * Schedule a thread to resume execution and record how long it voluntarily 1901 * slept. We also update the pctcpu, interactivity, and priority. 1902 */ 1903 void 1904 sched_wakeup(struct thread *td) 1905 { 1906 struct td_sched *ts; 1907 int slptick; 1908 1909 THREAD_LOCK_ASSERT(td, MA_OWNED); 1910 ts = td->td_sched; 1911 td->td_flags &= ~TDF_CANSWAP; 1912 /* 1913 * If we slept for more than a tick update our interactivity and 1914 * priority. 1915 */ 1916 slptick = td->td_slptick; 1917 td->td_slptick = 0; 1918 if (slptick && slptick != ticks) { 1919 u_int hzticks; 1920 1921 hzticks = (ticks - slptick) << SCHED_TICK_SHIFT; 1922 ts->ts_slptime += hzticks; 1923 sched_interact_update(td); 1924 sched_pctcpu_update(ts); 1925 } 1926 /* Reset the slice value after we sleep. */ 1927 ts->ts_slice = sched_slice; 1928 sched_add(td, SRQ_BORING); 1929 } 1930 1931 /* 1932 * Penalize the parent for creating a new child and initialize the child's 1933 * priority. 1934 */ 1935 void 1936 sched_fork(struct thread *td, struct thread *child) 1937 { 1938 THREAD_LOCK_ASSERT(td, MA_OWNED); 1939 sched_fork_thread(td, child); 1940 /* 1941 * Penalize the parent and child for forking. 1942 */ 1943 sched_interact_fork(child); 1944 sched_priority(child); 1945 td->td_sched->ts_runtime += tickincr; 1946 sched_interact_update(td); 1947 sched_priority(td); 1948 } 1949 1950 /* 1951 * Fork a new thread, may be within the same process. 1952 */ 1953 void 1954 sched_fork_thread(struct thread *td, struct thread *child) 1955 { 1956 struct td_sched *ts; 1957 struct td_sched *ts2; 1958 1959 THREAD_LOCK_ASSERT(td, MA_OWNED); 1960 /* 1961 * Initialize child. 1962 */ 1963 ts = td->td_sched; 1964 ts2 = child->td_sched; 1965 child->td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1966 child->td_cpuset = cpuset_ref(td->td_cpuset); 1967 ts2->ts_cpu = ts->ts_cpu; 1968 ts2->ts_flags = 0; 1969 /* 1970 * Grab our parents cpu estimation information and priority. 1971 */ 1972 ts2->ts_ticks = ts->ts_ticks; 1973 ts2->ts_ltick = ts->ts_ltick; 1974 ts2->ts_incrtick = ts->ts_incrtick; 1975 ts2->ts_ftick = ts->ts_ftick; 1976 child->td_user_pri = td->td_user_pri; 1977 child->td_base_user_pri = td->td_base_user_pri; 1978 /* 1979 * And update interactivity score. 1980 */ 1981 ts2->ts_slptime = ts->ts_slptime; 1982 ts2->ts_runtime = ts->ts_runtime; 1983 ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */ 1984 #ifdef KTR 1985 bzero(ts2->ts_name, sizeof(ts2->ts_name)); 1986 #endif 1987 } 1988 1989 /* 1990 * Adjust the priority class of a thread. 1991 */ 1992 void 1993 sched_class(struct thread *td, int class) 1994 { 1995 1996 THREAD_LOCK_ASSERT(td, MA_OWNED); 1997 if (td->td_pri_class == class) 1998 return; 1999 td->td_pri_class = class; 2000 } 2001 2002 /* 2003 * Return some of the child's priority and interactivity to the parent. 2004 */ 2005 void 2006 sched_exit(struct proc *p, struct thread *child) 2007 { 2008 struct thread *td; 2009 2010 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit", 2011 "prio:td", child->td_priority); 2012 PROC_LOCK_ASSERT(p, MA_OWNED); 2013 td = FIRST_THREAD_IN_PROC(p); 2014 sched_exit_thread(td, child); 2015 } 2016 2017 /* 2018 * Penalize another thread for the time spent on this one. This helps to 2019 * worsen the priority and interactivity of processes which schedule batch 2020 * jobs such as make. This has little effect on the make process itself but 2021 * causes new processes spawned by it to receive worse scores immediately. 2022 */ 2023 void 2024 sched_exit_thread(struct thread *td, struct thread *child) 2025 { 2026 2027 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit", 2028 "prio:td", child->td_priority); 2029 /* 2030 * Give the child's runtime to the parent without returning the 2031 * sleep time as a penalty to the parent. This causes shells that 2032 * launch expensive things to mark their children as expensive. 2033 */ 2034 thread_lock(td); 2035 td->td_sched->ts_runtime += child->td_sched->ts_runtime; 2036 sched_interact_update(td); 2037 sched_priority(td); 2038 thread_unlock(td); 2039 } 2040 2041 void 2042 sched_preempt(struct thread *td) 2043 { 2044 struct tdq *tdq; 2045 2046 thread_lock(td); 2047 tdq = TDQ_SELF(); 2048 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2049 tdq->tdq_ipipending = 0; 2050 if (td->td_priority > tdq->tdq_lowpri) { 2051 int flags; 2052 2053 flags = SW_INVOL | SW_PREEMPT; 2054 if (td->td_critnest > 1) 2055 td->td_owepreempt = 1; 2056 else if (TD_IS_IDLETHREAD(td)) 2057 mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL); 2058 else 2059 mi_switch(flags | SWT_REMOTEPREEMPT, NULL); 2060 } 2061 thread_unlock(td); 2062 } 2063 2064 /* 2065 * Fix priorities on return to user-space. Priorities may be elevated due 2066 * to static priorities in msleep() or similar. 2067 */ 2068 void 2069 sched_userret(struct thread *td) 2070 { 2071 /* 2072 * XXX we cheat slightly on the locking here to avoid locking in 2073 * the usual case. Setting td_priority here is essentially an 2074 * incomplete workaround for not setting it properly elsewhere. 2075 * Now that some interrupt handlers are threads, not setting it 2076 * properly elsewhere can clobber it in the window between setting 2077 * it here and returning to user mode, so don't waste time setting 2078 * it perfectly here. 2079 */ 2080 KASSERT((td->td_flags & TDF_BORROWING) == 0, 2081 ("thread with borrowed priority returning to userland")); 2082 if (td->td_priority != td->td_user_pri) { 2083 thread_lock(td); 2084 td->td_priority = td->td_user_pri; 2085 td->td_base_pri = td->td_user_pri; 2086 tdq_setlowpri(TDQ_SELF(), td); 2087 thread_unlock(td); 2088 } 2089 } 2090 2091 /* 2092 * Handle a stathz tick. This is really only relevant for timeshare 2093 * threads. 2094 */ 2095 void 2096 sched_clock(struct thread *td) 2097 { 2098 struct tdq *tdq; 2099 struct td_sched *ts; 2100 2101 THREAD_LOCK_ASSERT(td, MA_OWNED); 2102 tdq = TDQ_SELF(); 2103 #ifdef SMP 2104 /* 2105 * We run the long term load balancer infrequently on the first cpu. 2106 */ 2107 if (balance_tdq == tdq) { 2108 if (balance_ticks && --balance_ticks == 0) 2109 sched_balance(); 2110 } 2111 #endif 2112 /* 2113 * Save the old switch count so we have a record of the last ticks 2114 * activity. Initialize the new switch count based on our load. 2115 * If there is some activity seed it to reflect that. 2116 */ 2117 tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt; 2118 tdq->tdq_switchcnt = tdq->tdq_load; 2119 /* 2120 * Advance the insert index once for each tick to ensure that all 2121 * threads get a chance to run. 2122 */ 2123 if (tdq->tdq_idx == tdq->tdq_ridx) { 2124 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; 2125 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) 2126 tdq->tdq_ridx = tdq->tdq_idx; 2127 } 2128 ts = td->td_sched; 2129 if (td->td_pri_class & PRI_FIFO_BIT) 2130 return; 2131 if (td->td_pri_class == PRI_TIMESHARE) { 2132 /* 2133 * We used a tick; charge it to the thread so 2134 * that we can compute our interactivity. 2135 */ 2136 td->td_sched->ts_runtime += tickincr; 2137 sched_interact_update(td); 2138 sched_priority(td); 2139 } 2140 /* 2141 * We used up one time slice. 2142 */ 2143 if (--ts->ts_slice > 0) 2144 return; 2145 /* 2146 * We're out of time, force a requeue at userret(). 2147 */ 2148 ts->ts_slice = sched_slice; 2149 td->td_flags |= TDF_NEEDRESCHED; 2150 } 2151 2152 /* 2153 * Called once per hz tick. Used for cpu utilization information. This 2154 * is easier than trying to scale based on stathz. 2155 */ 2156 void 2157 sched_tick(void) 2158 { 2159 struct td_sched *ts; 2160 2161 ts = curthread->td_sched; 2162 /* 2163 * Ticks is updated asynchronously on a single cpu. Check here to 2164 * avoid incrementing ts_ticks multiple times in a single tick. 2165 */ 2166 if (ts->ts_incrtick == ticks) 2167 return; 2168 /* Adjust ticks for pctcpu */ 2169 ts->ts_ticks += 1 << SCHED_TICK_SHIFT; 2170 ts->ts_ltick = ticks; 2171 ts->ts_incrtick = ticks; 2172 /* 2173 * Update if we've exceeded our desired tick threshhold by over one 2174 * second. 2175 */ 2176 if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick) 2177 sched_pctcpu_update(ts); 2178 } 2179 2180 /* 2181 * Return whether the current CPU has runnable tasks. Used for in-kernel 2182 * cooperative idle threads. 2183 */ 2184 int 2185 sched_runnable(void) 2186 { 2187 struct tdq *tdq; 2188 int load; 2189 2190 load = 1; 2191 2192 tdq = TDQ_SELF(); 2193 if ((curthread->td_flags & TDF_IDLETD) != 0) { 2194 if (tdq->tdq_load > 0) 2195 goto out; 2196 } else 2197 if (tdq->tdq_load - 1 > 0) 2198 goto out; 2199 load = 0; 2200 out: 2201 return (load); 2202 } 2203 2204 /* 2205 * Choose the highest priority thread to run. The thread is removed from 2206 * the run-queue while running however the load remains. For SMP we set 2207 * the tdq in the global idle bitmask if it idles here. 2208 */ 2209 struct thread * 2210 sched_choose(void) 2211 { 2212 struct thread *td; 2213 struct tdq *tdq; 2214 2215 tdq = TDQ_SELF(); 2216 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2217 td = tdq_choose(tdq); 2218 if (td) { 2219 td->td_sched->ts_ltick = ticks; 2220 tdq_runq_rem(tdq, td); 2221 tdq->tdq_lowpri = td->td_priority; 2222 return (td); 2223 } 2224 tdq->tdq_lowpri = PRI_MAX_IDLE; 2225 return (PCPU_GET(idlethread)); 2226 } 2227 2228 /* 2229 * Set owepreempt if necessary. Preemption never happens directly in ULE, 2230 * we always request it once we exit a critical section. 2231 */ 2232 static inline void 2233 sched_setpreempt(struct thread *td) 2234 { 2235 struct thread *ctd; 2236 int cpri; 2237 int pri; 2238 2239 THREAD_LOCK_ASSERT(curthread, MA_OWNED); 2240 2241 ctd = curthread; 2242 pri = td->td_priority; 2243 cpri = ctd->td_priority; 2244 if (pri < cpri) 2245 ctd->td_flags |= TDF_NEEDRESCHED; 2246 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) 2247 return; 2248 if (!sched_shouldpreempt(pri, cpri, 0)) 2249 return; 2250 ctd->td_owepreempt = 1; 2251 } 2252 2253 /* 2254 * Add a thread to a thread queue. Select the appropriate runq and add the 2255 * thread to it. This is the internal function called when the tdq is 2256 * predetermined. 2257 */ 2258 void 2259 tdq_add(struct tdq *tdq, struct thread *td, int flags) 2260 { 2261 2262 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2263 KASSERT((td->td_inhibitors == 0), 2264 ("sched_add: trying to run inhibited thread")); 2265 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 2266 ("sched_add: bad thread state")); 2267 KASSERT(td->td_flags & TDF_INMEM, 2268 ("sched_add: thread swapped out")); 2269 2270 if (td->td_priority < tdq->tdq_lowpri) 2271 tdq->tdq_lowpri = td->td_priority; 2272 tdq_runq_add(tdq, td, flags); 2273 tdq_load_add(tdq, td); 2274 } 2275 2276 /* 2277 * Select the target thread queue and add a thread to it. Request 2278 * preemption or IPI a remote processor if required. 2279 */ 2280 void 2281 sched_add(struct thread *td, int flags) 2282 { 2283 struct tdq *tdq; 2284 #ifdef SMP 2285 int cpu; 2286 #endif 2287 2288 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", 2289 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 2290 sched_tdname(curthread)); 2291 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup", 2292 KTR_ATTR_LINKED, sched_tdname(td)); 2293 THREAD_LOCK_ASSERT(td, MA_OWNED); 2294 /* 2295 * Recalculate the priority before we select the target cpu or 2296 * run-queue. 2297 */ 2298 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 2299 sched_priority(td); 2300 #ifdef SMP 2301 /* 2302 * Pick the destination cpu and if it isn't ours transfer to the 2303 * target cpu. 2304 */ 2305 cpu = sched_pickcpu(td, flags); 2306 tdq = sched_setcpu(td, cpu, flags); 2307 tdq_add(tdq, td, flags); 2308 if (cpu != PCPU_GET(cpuid)) { 2309 tdq_notify(tdq, td); 2310 return; 2311 } 2312 #else 2313 tdq = TDQ_SELF(); 2314 TDQ_LOCK(tdq); 2315 /* 2316 * Now that the thread is moving to the run-queue, set the lock 2317 * to the scheduler's lock. 2318 */ 2319 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 2320 tdq_add(tdq, td, flags); 2321 #endif 2322 if (!(flags & SRQ_YIELDING)) 2323 sched_setpreempt(td); 2324 } 2325 2326 /* 2327 * Remove a thread from a run-queue without running it. This is used 2328 * when we're stealing a thread from a remote queue. Otherwise all threads 2329 * exit by calling sched_exit_thread() and sched_throw() themselves. 2330 */ 2331 void 2332 sched_rem(struct thread *td) 2333 { 2334 struct tdq *tdq; 2335 2336 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem", 2337 "prio:%d", td->td_priority); 2338 tdq = TDQ_CPU(td->td_sched->ts_cpu); 2339 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2340 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2341 KASSERT(TD_ON_RUNQ(td), 2342 ("sched_rem: thread not on run queue")); 2343 tdq_runq_rem(tdq, td); 2344 tdq_load_rem(tdq, td); 2345 TD_SET_CAN_RUN(td); 2346 if (td->td_priority == tdq->tdq_lowpri) 2347 tdq_setlowpri(tdq, NULL); 2348 } 2349 2350 /* 2351 * Fetch cpu utilization information. Updates on demand. 2352 */ 2353 fixpt_t 2354 sched_pctcpu(struct thread *td) 2355 { 2356 fixpt_t pctcpu; 2357 struct td_sched *ts; 2358 2359 pctcpu = 0; 2360 ts = td->td_sched; 2361 if (ts == NULL) 2362 return (0); 2363 2364 THREAD_LOCK_ASSERT(td, MA_OWNED); 2365 if (ts->ts_ticks) { 2366 int rtick; 2367 2368 sched_pctcpu_update(ts); 2369 /* How many rtick per second ? */ 2370 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); 2371 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; 2372 } 2373 2374 return (pctcpu); 2375 } 2376 2377 /* 2378 * Enforce affinity settings for a thread. Called after adjustments to 2379 * cpumask. 2380 */ 2381 void 2382 sched_affinity(struct thread *td) 2383 { 2384 #ifdef SMP 2385 struct td_sched *ts; 2386 int cpu; 2387 2388 THREAD_LOCK_ASSERT(td, MA_OWNED); 2389 ts = td->td_sched; 2390 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) 2391 return; 2392 if (TD_ON_RUNQ(td)) { 2393 sched_rem(td); 2394 sched_add(td, SRQ_BORING); 2395 return; 2396 } 2397 if (!TD_IS_RUNNING(td)) 2398 return; 2399 td->td_flags |= TDF_NEEDRESCHED; 2400 if (!THREAD_CAN_MIGRATE(td)) 2401 return; 2402 /* 2403 * Assign the new cpu and force a switch before returning to 2404 * userspace. If the target thread is not running locally send 2405 * an ipi to force the issue. 2406 */ 2407 cpu = ts->ts_cpu; 2408 ts->ts_cpu = sched_pickcpu(td, 0); 2409 if (cpu != PCPU_GET(cpuid)) 2410 ipi_cpu(cpu, IPI_PREEMPT); 2411 #endif 2412 } 2413 2414 /* 2415 * Bind a thread to a target cpu. 2416 */ 2417 void 2418 sched_bind(struct thread *td, int cpu) 2419 { 2420 struct td_sched *ts; 2421 2422 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 2423 KASSERT(td == curthread, ("sched_bind: can only bind curthread")); 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 KASSERT(td == curthread, ("sched_unbind: can only bind curthread")); 2446 ts = td->td_sched; 2447 if ((ts->ts_flags & TSF_BOUND) == 0) 2448 return; 2449 ts->ts_flags &= ~TSF_BOUND; 2450 sched_unpin(); 2451 } 2452 2453 int 2454 sched_is_bound(struct thread *td) 2455 { 2456 THREAD_LOCK_ASSERT(td, MA_OWNED); 2457 return (td->td_sched->ts_flags & TSF_BOUND); 2458 } 2459 2460 /* 2461 * Basic yield call. 2462 */ 2463 void 2464 sched_relinquish(struct thread *td) 2465 { 2466 thread_lock(td); 2467 mi_switch(SW_VOL | SWT_RELINQUISH, NULL); 2468 thread_unlock(td); 2469 } 2470 2471 /* 2472 * Return the total system load. 2473 */ 2474 int 2475 sched_load(void) 2476 { 2477 #ifdef SMP 2478 int total; 2479 int i; 2480 2481 total = 0; 2482 CPU_FOREACH(i) 2483 total += TDQ_CPU(i)->tdq_sysload; 2484 return (total); 2485 #else 2486 return (TDQ_SELF()->tdq_sysload); 2487 #endif 2488 } 2489 2490 int 2491 sched_sizeof_proc(void) 2492 { 2493 return (sizeof(struct proc)); 2494 } 2495 2496 int 2497 sched_sizeof_thread(void) 2498 { 2499 return (sizeof(struct thread) + sizeof(struct td_sched)); 2500 } 2501 2502 #ifdef SMP 2503 #define TDQ_IDLESPIN(tdq) \ 2504 ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0) 2505 #else 2506 #define TDQ_IDLESPIN(tdq) 1 2507 #endif 2508 2509 /* 2510 * The actual idle process. 2511 */ 2512 void 2513 sched_idletd(void *dummy) 2514 { 2515 struct thread *td; 2516 struct tdq *tdq; 2517 int switchcnt; 2518 int i; 2519 2520 mtx_assert(&Giant, MA_NOTOWNED); 2521 td = curthread; 2522 tdq = TDQ_SELF(); 2523 for (;;) { 2524 #ifdef SMP 2525 if (tdq_idled(tdq) == 0) 2526 continue; 2527 #endif 2528 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2529 /* 2530 * If we're switching very frequently, spin while checking 2531 * for load rather than entering a low power state that 2532 * may require an IPI. However, don't do any busy 2533 * loops while on SMT machines as this simply steals 2534 * cycles from cores doing useful work. 2535 */ 2536 if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) { 2537 for (i = 0; i < sched_idlespins; i++) { 2538 if (tdq->tdq_load) 2539 break; 2540 cpu_spinwait(); 2541 } 2542 } 2543 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2544 if (tdq->tdq_load == 0) 2545 cpu_idle(switchcnt > 1); 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 /* 2609 * Create on first use to catch odd startup conditons. 2610 */ 2611 char * 2612 sched_tdname(struct thread *td) 2613 { 2614 #ifdef KTR 2615 struct td_sched *ts; 2616 2617 ts = td->td_sched; 2618 if (ts->ts_name[0] == '\0') 2619 snprintf(ts->ts_name, sizeof(ts->ts_name), 2620 "%s tid %d", td->td_name, td->td_tid); 2621 return (ts->ts_name); 2622 #else 2623 return (td->td_name); 2624 #endif 2625 } 2626 2627 #ifdef SMP 2628 2629 /* 2630 * Build the CPU topology dump string. Is recursively called to collect 2631 * the topology tree. 2632 */ 2633 static int 2634 sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg, 2635 int indent) 2636 { 2637 int i, first; 2638 2639 sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent, 2640 "", indent, cg->cg_level); 2641 sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"0x%x\">", indent, "", 2642 cg->cg_count, cg->cg_mask); 2643 first = TRUE; 2644 for (i = 0; i < MAXCPU; i++) { 2645 if ((cg->cg_mask & (1 << i)) != 0) { 2646 if (!first) 2647 sbuf_printf(sb, ", "); 2648 else 2649 first = FALSE; 2650 sbuf_printf(sb, "%d", i); 2651 } 2652 } 2653 sbuf_printf(sb, "</cpu>\n"); 2654 2655 if (cg->cg_flags != 0) { 2656 sbuf_printf(sb, "%*s <flags>", indent, ""); 2657 if ((cg->cg_flags & CG_FLAG_HTT) != 0) 2658 sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>"); 2659 if ((cg->cg_flags & CG_FLAG_THREAD) != 0) 2660 sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>"); 2661 if ((cg->cg_flags & CG_FLAG_SMT) != 0) 2662 sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>"); 2663 sbuf_printf(sb, "</flags>\n"); 2664 } 2665 2666 if (cg->cg_children > 0) { 2667 sbuf_printf(sb, "%*s <children>\n", indent, ""); 2668 for (i = 0; i < cg->cg_children; i++) 2669 sysctl_kern_sched_topology_spec_internal(sb, 2670 &cg->cg_child[i], indent+2); 2671 sbuf_printf(sb, "%*s </children>\n", indent, ""); 2672 } 2673 sbuf_printf(sb, "%*s</group>\n", indent, ""); 2674 return (0); 2675 } 2676 2677 /* 2678 * Sysctl handler for retrieving topology dump. It's a wrapper for 2679 * the recursive sysctl_kern_smp_topology_spec_internal(). 2680 */ 2681 static int 2682 sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS) 2683 { 2684 struct sbuf *topo; 2685 int err; 2686 2687 KASSERT(cpu_top != NULL, ("cpu_top isn't initialized")); 2688 2689 topo = sbuf_new(NULL, NULL, 500, SBUF_AUTOEXTEND); 2690 if (topo == NULL) 2691 return (ENOMEM); 2692 2693 sbuf_printf(topo, "<groups>\n"); 2694 err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1); 2695 sbuf_printf(topo, "</groups>\n"); 2696 2697 if (err == 0) { 2698 sbuf_finish(topo); 2699 err = SYSCTL_OUT(req, sbuf_data(topo), sbuf_len(topo)); 2700 } 2701 sbuf_delete(topo); 2702 return (err); 2703 } 2704 #endif 2705 2706 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); 2707 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0, 2708 "Scheduler name"); 2709 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 2710 "Slice size for timeshare threads"); 2711 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, 2712 "Interactivity score threshold"); 2713 SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh, 2714 0,"Min priority for preemption, lower priorities have greater precedence"); 2715 SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 2716 0,"Controls whether static kernel priorities are assigned to sleeping threads."); 2717 SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 2718 0,"Number of times idle will spin waiting for new work."); 2719 SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW, &sched_idlespinthresh, 2720 0,"Threshold before we will permit idle spinning."); 2721 #ifdef SMP 2722 SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0, 2723 "Number of hz ticks to keep thread affinity for"); 2724 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, 2725 "Enables the long-term load balancer"); 2726 SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW, 2727 &balance_interval, 0, 2728 "Average frequency in stathz ticks to run the long-term balancer"); 2729 SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0, 2730 "Steals work from another hyper-threaded core on idle"); 2731 SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0, 2732 "Attempts to steal work from other cores before idling"); 2733 SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0, 2734 "Minimum load on remote cpu before we'll steal"); 2735 2736 /* Retrieve SMP topology */ 2737 SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING | 2738 CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A", 2739 "XML dump of detected CPU topology"); 2740 #endif 2741 2742 /* ps compat. All cpu percentages from ULE are weighted. */ 2743 static int ccpu = 0; 2744 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 2745