1 /*- 2 * Copyright (c) 2002-2007, Jeffrey Roberson <jeff@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 /* 28 * This file implements the ULE scheduler. ULE supports independent CPU 29 * run queues and fine grain locking. It has superior interactive 30 * performance under load even on uni-processor systems. 31 * 32 * etymology: 33 * ULE is the last three letters in schedule. It owes its name to a 34 * generic user created for a scheduling system by Paul Mikesell at 35 * Isilon Systems and a general lack of creativity on the part of the author. 36 */ 37 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include "opt_hwpmc_hooks.h" 42 #include "opt_kdtrace.h" 43 #include "opt_sched.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/kdb.h> 48 #include <sys/kernel.h> 49 #include <sys/ktr.h> 50 #include <sys/lock.h> 51 #include <sys/mutex.h> 52 #include <sys/proc.h> 53 #include <sys/resource.h> 54 #include <sys/resourcevar.h> 55 #include <sys/sched.h> 56 #include <sys/smp.h> 57 #include <sys/sx.h> 58 #include <sys/sysctl.h> 59 #include <sys/sysproto.h> 60 #include <sys/turnstile.h> 61 #include <sys/umtx.h> 62 #include <sys/vmmeter.h> 63 #include <sys/cpuset.h> 64 #include <sys/sbuf.h> 65 #ifdef KTRACE 66 #include <sys/uio.h> 67 #include <sys/ktrace.h> 68 #endif 69 70 #ifdef HWPMC_HOOKS 71 #include <sys/pmckern.h> 72 #endif 73 74 #ifdef KDTRACE_HOOKS 75 #include <sys/dtrace_bsd.h> 76 int dtrace_vtime_active; 77 dtrace_vtime_switch_func_t dtrace_vtime_switch_func; 78 #endif 79 80 #include <machine/cpu.h> 81 #include <machine/smp.h> 82 83 #if defined(__sparc64__) || defined(__mips__) 84 #error "This architecture is not currently compatible with ULE" 85 #endif 86 87 #define KTR_ULE 0 88 89 #define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX))) 90 #define TDQ_NAME_LEN (sizeof("sched lock ") + sizeof(__XSTRING(MAXCPU))) 91 #define TDQ_LOADNAME_LEN (PCPU_NAME_LEN + sizeof(" load")) 92 93 /* 94 * Thread scheduler specific section. All fields are protected 95 * by the thread lock. 96 */ 97 struct td_sched { 98 struct runq *ts_runq; /* Run-queue we're queued on. */ 99 short ts_flags; /* TSF_* flags. */ 100 u_char ts_cpu; /* CPU that we have affinity for. */ 101 int ts_rltick; /* Real last tick, for affinity. */ 102 int ts_slice; /* Ticks of slice remaining. */ 103 u_int ts_slptime; /* Number of ticks we vol. slept */ 104 u_int ts_runtime; /* Number of ticks we were running */ 105 int ts_ltick; /* Last tick that we were running on */ 106 int ts_incrtick; /* Last tick that we incremented on */ 107 int ts_ftick; /* First tick that we were running on */ 108 int ts_ticks; /* Tick count */ 109 #ifdef KTR 110 char ts_name[TS_NAME_LEN]; 111 #endif 112 }; 113 /* flags kept in ts_flags */ 114 #define TSF_BOUND 0x0001 /* Thread can not migrate. */ 115 #define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */ 116 117 static struct td_sched td_sched0; 118 119 #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0) 120 #define THREAD_CAN_SCHED(td, cpu) \ 121 CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask) 122 123 /* 124 * Cpu percentage computation macros and defines. 125 * 126 * SCHED_TICK_SECS: Number of seconds to average the cpu usage across. 127 * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across. 128 * SCHED_TICK_MAX: Maximum number of ticks before scaling back. 129 * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results. 130 * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count. 131 * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks. 132 */ 133 #define SCHED_TICK_SECS 10 134 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS) 135 #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz) 136 #define SCHED_TICK_SHIFT 10 137 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT) 138 #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz)) 139 140 /* 141 * These macros determine priorities for non-interactive threads. They are 142 * assigned a priority based on their recent cpu utilization as expressed 143 * by the ratio of ticks to the tick total. NHALF priorities at the start 144 * and end of the MIN to MAX timeshare range are only reachable with negative 145 * or positive nice respectively. 146 * 147 * PRI_RANGE: Priority range for utilization dependent priorities. 148 * PRI_NRESV: Number of nice values. 149 * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total. 150 * PRI_NICE: Determines the part of the priority inherited from nice. 151 */ 152 #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN) 153 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) 154 #define SCHED_PRI_MIN (PRI_MIN_TIMESHARE + SCHED_PRI_NHALF) 155 #define SCHED_PRI_MAX (PRI_MAX_TIMESHARE - SCHED_PRI_NHALF) 156 #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN) 157 #define SCHED_PRI_TICKS(ts) \ 158 (SCHED_TICK_HZ((ts)) / \ 159 (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE)) 160 #define SCHED_PRI_NICE(nice) (nice) 161 162 /* 163 * These determine the interactivity of a process. Interactivity differs from 164 * cpu utilization in that it expresses the voluntary time slept vs time ran 165 * while cpu utilization includes all time not running. This more accurately 166 * models the intent of the thread. 167 * 168 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 169 * before throttling back. 170 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. 171 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 172 * INTERACT_THRESH: Threshhold for placement on the current runq. 173 */ 174 #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT) 175 #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT) 176 #define SCHED_INTERACT_MAX (100) 177 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 178 #define SCHED_INTERACT_THRESH (30) 179 180 /* 181 * tickincr: Converts a stathz tick into a hz domain scaled by 182 * the shift factor. Without the shift the error rate 183 * due to rounding would be unacceptably high. 184 * realstathz: stathz is sometimes 0 and run off of hz. 185 * sched_slice: Runtime of each thread before rescheduling. 186 * preempt_thresh: Priority threshold for preemption and remote IPIs. 187 */ 188 static int sched_interact = SCHED_INTERACT_THRESH; 189 static int realstathz; 190 static int tickincr; 191 static int sched_slice = 1; 192 #ifdef PREEMPTION 193 #ifdef FULL_PREEMPTION 194 static int preempt_thresh = PRI_MAX_IDLE; 195 #else 196 static int preempt_thresh = PRI_MIN_KERN; 197 #endif 198 #else 199 static int preempt_thresh = 0; 200 #endif 201 static int static_boost = PRI_MIN_TIMESHARE; 202 static int sched_idlespins = 10000; 203 static int sched_idlespinthresh = 4; 204 205 /* 206 * tdq - per processor runqs and statistics. All fields are protected by the 207 * tdq_lock. The load and lowpri may be accessed without to avoid excess 208 * locking in sched_pickcpu(); 209 */ 210 struct tdq { 211 /* Ordered to improve efficiency of cpu_search() and switch(). */ 212 struct mtx tdq_lock; /* run queue lock. */ 213 struct cpu_group *tdq_cg; /* Pointer to cpu topology. */ 214 volatile int tdq_load; /* Aggregate load. */ 215 int tdq_sysload; /* For loadavg, !ITHD load. */ 216 int tdq_transferable; /* Transferable thread count. */ 217 short tdq_switchcnt; /* Switches this tick. */ 218 short tdq_oldswitchcnt; /* Switches last tick. */ 219 u_char tdq_lowpri; /* Lowest priority thread. */ 220 u_char tdq_ipipending; /* IPI pending. */ 221 u_char tdq_idx; /* Current insert index. */ 222 u_char tdq_ridx; /* Current removal index. */ 223 struct runq tdq_realtime; /* real-time run queue. */ 224 struct runq tdq_timeshare; /* timeshare run queue. */ 225 struct runq tdq_idle; /* Queue of IDLE threads. */ 226 char tdq_name[TDQ_NAME_LEN]; 227 #ifdef KTR 228 char tdq_loadname[TDQ_LOADNAME_LEN]; 229 #endif 230 } __aligned(64); 231 232 /* Idle thread states and config. */ 233 #define TDQ_RUNNING 1 234 #define TDQ_IDLE 2 235 236 #ifdef SMP 237 struct cpu_group *cpu_top; /* CPU topology */ 238 239 #define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000)) 240 #define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity)) 241 242 /* 243 * Run-time tunables. 244 */ 245 static int rebalance = 1; 246 static int balance_interval = 128; /* Default set in sched_initticks(). */ 247 static int affinity; 248 static int steal_htt = 1; 249 static int steal_idle = 1; 250 static int steal_thresh = 2; 251 252 /* 253 * One thread queue per processor. 254 */ 255 static struct tdq tdq_cpu[MAXCPU]; 256 static struct tdq *balance_tdq; 257 static int balance_ticks; 258 259 #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)]) 260 #define TDQ_CPU(x) (&tdq_cpu[(x)]) 261 #define TDQ_ID(x) ((int)((x) - tdq_cpu)) 262 #else /* !SMP */ 263 static struct tdq tdq_cpu; 264 265 #define TDQ_ID(x) (0) 266 #define TDQ_SELF() (&tdq_cpu) 267 #define TDQ_CPU(x) (&tdq_cpu) 268 #endif 269 270 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type)) 271 #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t))) 272 #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f)) 273 #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t))) 274 #define TDQ_LOCKPTR(t) (&(t)->tdq_lock) 275 276 static void sched_priority(struct thread *); 277 static void sched_thread_priority(struct thread *, u_char); 278 static int sched_interact_score(struct thread *); 279 static void sched_interact_update(struct thread *); 280 static void sched_interact_fork(struct thread *); 281 static void sched_pctcpu_update(struct td_sched *); 282 283 /* Operations on per processor queues */ 284 static struct thread *tdq_choose(struct tdq *); 285 static void tdq_setup(struct tdq *); 286 static void tdq_load_add(struct tdq *, struct thread *); 287 static void tdq_load_rem(struct tdq *, struct thread *); 288 static __inline void tdq_runq_add(struct tdq *, struct thread *, int); 289 static __inline void tdq_runq_rem(struct tdq *, struct thread *); 290 static inline int sched_shouldpreempt(int, int, int); 291 void tdq_print(int cpu); 292 static void runq_print(struct runq *rq); 293 static void tdq_add(struct tdq *, struct thread *, int); 294 #ifdef SMP 295 static int tdq_move(struct tdq *, struct tdq *); 296 static int tdq_idled(struct tdq *); 297 static void tdq_notify(struct tdq *, struct thread *); 298 static struct thread *tdq_steal(struct tdq *, int); 299 static struct thread *runq_steal(struct runq *, int); 300 static int sched_pickcpu(struct thread *, int); 301 static void sched_balance(void); 302 static int sched_balance_pair(struct tdq *, struct tdq *); 303 static inline struct tdq *sched_setcpu(struct thread *, int, int); 304 static inline struct mtx *thread_block_switch(struct thread *); 305 static inline void thread_unblock_switch(struct thread *, struct mtx *); 306 static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int); 307 static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS); 308 static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, 309 struct cpu_group *cg, int indent); 310 #endif 311 312 static void sched_setup(void *dummy); 313 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL); 314 315 static void sched_initticks(void *dummy); 316 SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, 317 NULL); 318 319 /* 320 * Print the threads waiting on a run-queue. 321 */ 322 static void 323 runq_print(struct runq *rq) 324 { 325 struct rqhead *rqh; 326 struct thread *td; 327 int pri; 328 int j; 329 int i; 330 331 for (i = 0; i < RQB_LEN; i++) { 332 printf("\t\trunq bits %d 0x%zx\n", 333 i, rq->rq_status.rqb_bits[i]); 334 for (j = 0; j < RQB_BPW; j++) 335 if (rq->rq_status.rqb_bits[i] & (1ul << j)) { 336 pri = j + (i << RQB_L2BPW); 337 rqh = &rq->rq_queues[pri]; 338 TAILQ_FOREACH(td, rqh, td_runq) { 339 printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n", 340 td, td->td_name, td->td_priority, 341 td->td_rqindex, pri); 342 } 343 } 344 } 345 } 346 347 /* 348 * Print the status of a per-cpu thread queue. Should be a ddb show cmd. 349 */ 350 void 351 tdq_print(int cpu) 352 { 353 struct tdq *tdq; 354 355 tdq = TDQ_CPU(cpu); 356 357 printf("tdq %d:\n", TDQ_ID(tdq)); 358 printf("\tlock %p\n", TDQ_LOCKPTR(tdq)); 359 printf("\tLock name: %s\n", tdq->tdq_name); 360 printf("\tload: %d\n", tdq->tdq_load); 361 printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt); 362 printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt); 363 printf("\ttimeshare idx: %d\n", tdq->tdq_idx); 364 printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx); 365 printf("\tload transferable: %d\n", tdq->tdq_transferable); 366 printf("\tlowest priority: %d\n", tdq->tdq_lowpri); 367 printf("\trealtime runq:\n"); 368 runq_print(&tdq->tdq_realtime); 369 printf("\ttimeshare runq:\n"); 370 runq_print(&tdq->tdq_timeshare); 371 printf("\tidle runq:\n"); 372 runq_print(&tdq->tdq_idle); 373 } 374 375 static inline int 376 sched_shouldpreempt(int pri, int cpri, int remote) 377 { 378 /* 379 * If the new priority is not better than the current priority there is 380 * nothing to do. 381 */ 382 if (pri >= cpri) 383 return (0); 384 /* 385 * Always preempt idle. 386 */ 387 if (cpri >= PRI_MIN_IDLE) 388 return (1); 389 /* 390 * If preemption is disabled don't preempt others. 391 */ 392 if (preempt_thresh == 0) 393 return (0); 394 /* 395 * Preempt if we exceed the threshold. 396 */ 397 if (pri <= preempt_thresh) 398 return (1); 399 /* 400 * If we're realtime or better and there is timeshare or worse running 401 * preempt only remote processors. 402 */ 403 if (remote && pri <= PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME) 404 return (1); 405 return (0); 406 } 407 408 #define TS_RQ_PPQ (((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS) 409 /* 410 * Add a thread to the actual run-queue. Keeps transferable counts up to 411 * date with what is actually on the run-queue. Selects the correct 412 * queue position for timeshare threads. 413 */ 414 static __inline void 415 tdq_runq_add(struct tdq *tdq, struct thread *td, int flags) 416 { 417 struct td_sched *ts; 418 u_char pri; 419 420 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 421 THREAD_LOCK_ASSERT(td, MA_OWNED); 422 423 pri = td->td_priority; 424 ts = td->td_sched; 425 TD_SET_RUNQ(td); 426 if (THREAD_CAN_MIGRATE(td)) { 427 tdq->tdq_transferable++; 428 ts->ts_flags |= TSF_XFERABLE; 429 } 430 if (pri <= PRI_MAX_REALTIME) { 431 ts->ts_runq = &tdq->tdq_realtime; 432 } else if (pri <= PRI_MAX_TIMESHARE) { 433 ts->ts_runq = &tdq->tdq_timeshare; 434 KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE, 435 ("Invalid priority %d on timeshare runq", pri)); 436 /* 437 * This queue contains only priorities between MIN and MAX 438 * realtime. Use the whole queue to represent these values. 439 */ 440 if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) { 441 pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ; 442 pri = (pri + tdq->tdq_idx) % RQ_NQS; 443 /* 444 * This effectively shortens the queue by one so we 445 * can have a one slot difference between idx and 446 * ridx while we wait for threads to drain. 447 */ 448 if (tdq->tdq_ridx != tdq->tdq_idx && 449 pri == tdq->tdq_ridx) 450 pri = (unsigned char)(pri - 1) % RQ_NQS; 451 } else 452 pri = tdq->tdq_ridx; 453 runq_add_pri(ts->ts_runq, td, pri, flags); 454 return; 455 } else 456 ts->ts_runq = &tdq->tdq_idle; 457 runq_add(ts->ts_runq, td, flags); 458 } 459 460 /* 461 * Remove a thread from a run-queue. This typically happens when a thread 462 * is selected to run. Running threads are not on the queue and the 463 * transferable count does not reflect them. 464 */ 465 static __inline void 466 tdq_runq_rem(struct tdq *tdq, struct thread *td) 467 { 468 struct td_sched *ts; 469 470 ts = td->td_sched; 471 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 472 KASSERT(ts->ts_runq != NULL, 473 ("tdq_runq_remove: thread %p null ts_runq", td)); 474 if (ts->ts_flags & TSF_XFERABLE) { 475 tdq->tdq_transferable--; 476 ts->ts_flags &= ~TSF_XFERABLE; 477 } 478 if (ts->ts_runq == &tdq->tdq_timeshare) { 479 if (tdq->tdq_idx != tdq->tdq_ridx) 480 runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx); 481 else 482 runq_remove_idx(ts->ts_runq, td, NULL); 483 } else 484 runq_remove(ts->ts_runq, td); 485 } 486 487 /* 488 * Load is maintained for all threads RUNNING and ON_RUNQ. Add the load 489 * for this thread to the referenced thread queue. 490 */ 491 static void 492 tdq_load_add(struct tdq *tdq, struct thread *td) 493 { 494 495 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 496 THREAD_LOCK_ASSERT(td, MA_OWNED); 497 498 tdq->tdq_load++; 499 if ((td->td_flags & TDF_NOLOAD) == 0) 500 tdq->tdq_sysload++; 501 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load); 502 } 503 504 /* 505 * Remove the load from a thread that is transitioning to a sleep state or 506 * exiting. 507 */ 508 static void 509 tdq_load_rem(struct tdq *tdq, struct thread *td) 510 { 511 512 THREAD_LOCK_ASSERT(td, MA_OWNED); 513 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 514 KASSERT(tdq->tdq_load != 0, 515 ("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq))); 516 517 tdq->tdq_load--; 518 if ((td->td_flags & TDF_NOLOAD) == 0) 519 tdq->tdq_sysload--; 520 KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load); 521 } 522 523 /* 524 * Set lowpri to its exact value by searching the run-queue and 525 * evaluating curthread. curthread may be passed as an optimization. 526 */ 527 static void 528 tdq_setlowpri(struct tdq *tdq, struct thread *ctd) 529 { 530 struct thread *td; 531 532 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 533 if (ctd == NULL) 534 ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread; 535 td = tdq_choose(tdq); 536 if (td == NULL || td->td_priority > ctd->td_priority) 537 tdq->tdq_lowpri = ctd->td_priority; 538 else 539 tdq->tdq_lowpri = td->td_priority; 540 } 541 542 #ifdef SMP 543 struct cpu_search { 544 cpuset_t cs_mask; 545 u_int cs_load; 546 u_int cs_cpu; 547 int cs_limit; /* Min priority for low min load for high. */ 548 }; 549 550 #define CPU_SEARCH_LOWEST 0x1 551 #define CPU_SEARCH_HIGHEST 0x2 552 #define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST) 553 554 #define CPUSET_FOREACH(cpu, mask) \ 555 for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++) \ 556 if ((mask) & 1 << (cpu)) 557 558 static __inline int cpu_search(struct cpu_group *cg, struct cpu_search *low, 559 struct cpu_search *high, const int match); 560 int cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low); 561 int cpu_search_highest(struct cpu_group *cg, struct cpu_search *high); 562 int cpu_search_both(struct cpu_group *cg, struct cpu_search *low, 563 struct cpu_search *high); 564 565 /* 566 * This routine compares according to the match argument and should be 567 * reduced in actual instantiations via constant propagation and dead code 568 * elimination. 569 */ 570 static __inline int 571 cpu_compare(int cpu, struct cpu_search *low, struct cpu_search *high, 572 const int match) 573 { 574 struct tdq *tdq; 575 576 tdq = TDQ_CPU(cpu); 577 if (match & CPU_SEARCH_LOWEST) 578 if (CPU_ISSET(cpu, &low->cs_mask) && 579 tdq->tdq_load < low->cs_load && 580 tdq->tdq_lowpri > low->cs_limit) { 581 low->cs_cpu = cpu; 582 low->cs_load = tdq->tdq_load; 583 } 584 if (match & CPU_SEARCH_HIGHEST) 585 if (CPU_ISSET(cpu, &high->cs_mask) && 586 tdq->tdq_load >= high->cs_limit && 587 tdq->tdq_load > high->cs_load && 588 tdq->tdq_transferable) { 589 high->cs_cpu = cpu; 590 high->cs_load = tdq->tdq_load; 591 } 592 return (tdq->tdq_load); 593 } 594 595 /* 596 * Search the tree of cpu_groups for the lowest or highest loaded cpu 597 * according to the match argument. This routine actually compares the 598 * load on all paths through the tree and finds the least loaded cpu on 599 * the least loaded path, which may differ from the least loaded cpu in 600 * the system. This balances work among caches and busses. 601 * 602 * This inline is instantiated in three forms below using constants for the 603 * match argument. It is reduced to the minimum set for each case. It is 604 * also recursive to the depth of the tree. 605 */ 606 static __inline int 607 cpu_search(struct cpu_group *cg, struct cpu_search *low, 608 struct cpu_search *high, const int match) 609 { 610 int total; 611 612 total = 0; 613 if (cg->cg_children) { 614 struct cpu_search lgroup; 615 struct cpu_search hgroup; 616 struct cpu_group *child; 617 u_int lload; 618 int hload; 619 int load; 620 int i; 621 622 lload = -1; 623 hload = -1; 624 for (i = 0; i < cg->cg_children; i++) { 625 child = &cg->cg_child[i]; 626 if (match & CPU_SEARCH_LOWEST) { 627 lgroup = *low; 628 lgroup.cs_load = -1; 629 } 630 if (match & CPU_SEARCH_HIGHEST) { 631 hgroup = *high; 632 lgroup.cs_load = 0; 633 } 634 switch (match) { 635 case CPU_SEARCH_LOWEST: 636 load = cpu_search_lowest(child, &lgroup); 637 break; 638 case CPU_SEARCH_HIGHEST: 639 load = cpu_search_highest(child, &hgroup); 640 break; 641 case CPU_SEARCH_BOTH: 642 load = cpu_search_both(child, &lgroup, &hgroup); 643 break; 644 } 645 total += load; 646 if (match & CPU_SEARCH_LOWEST) 647 if (load < lload || low->cs_cpu == -1) { 648 *low = lgroup; 649 lload = load; 650 } 651 if (match & CPU_SEARCH_HIGHEST) 652 if (load > hload || high->cs_cpu == -1) { 653 hload = load; 654 *high = hgroup; 655 } 656 } 657 } else { 658 int cpu; 659 660 CPUSET_FOREACH(cpu, cg->cg_mask) 661 total += cpu_compare(cpu, low, high, match); 662 } 663 return (total); 664 } 665 666 /* 667 * cpu_search instantiations must pass constants to maintain the inline 668 * optimization. 669 */ 670 int 671 cpu_search_lowest(struct cpu_group *cg, struct cpu_search *low) 672 { 673 return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST); 674 } 675 676 int 677 cpu_search_highest(struct cpu_group *cg, struct cpu_search *high) 678 { 679 return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST); 680 } 681 682 int 683 cpu_search_both(struct cpu_group *cg, struct cpu_search *low, 684 struct cpu_search *high) 685 { 686 return cpu_search(cg, low, high, CPU_SEARCH_BOTH); 687 } 688 689 /* 690 * Find the cpu with the least load via the least loaded path that has a 691 * lowpri greater than pri pri. A pri of -1 indicates any priority is 692 * acceptable. 693 */ 694 static inline int 695 sched_lowest(struct cpu_group *cg, cpuset_t mask, int pri) 696 { 697 struct cpu_search low; 698 699 low.cs_cpu = -1; 700 low.cs_load = -1; 701 low.cs_mask = mask; 702 low.cs_limit = pri; 703 cpu_search_lowest(cg, &low); 704 return low.cs_cpu; 705 } 706 707 /* 708 * Find the cpu with the highest load via the highest loaded path. 709 */ 710 static inline int 711 sched_highest(struct cpu_group *cg, cpuset_t mask, int minload) 712 { 713 struct cpu_search high; 714 715 high.cs_cpu = -1; 716 high.cs_load = 0; 717 high.cs_mask = mask; 718 high.cs_limit = minload; 719 cpu_search_highest(cg, &high); 720 return high.cs_cpu; 721 } 722 723 /* 724 * Simultaneously find the highest and lowest loaded cpu reachable via 725 * cg. 726 */ 727 static inline void 728 sched_both(struct cpu_group *cg, cpuset_t mask, int *lowcpu, int *highcpu) 729 { 730 struct cpu_search high; 731 struct cpu_search low; 732 733 low.cs_cpu = -1; 734 low.cs_limit = -1; 735 low.cs_load = -1; 736 low.cs_mask = mask; 737 high.cs_load = 0; 738 high.cs_cpu = -1; 739 high.cs_limit = -1; 740 high.cs_mask = mask; 741 cpu_search_both(cg, &low, &high); 742 *lowcpu = low.cs_cpu; 743 *highcpu = high.cs_cpu; 744 return; 745 } 746 747 static void 748 sched_balance_group(struct cpu_group *cg) 749 { 750 cpuset_t mask; 751 int high; 752 int low; 753 int i; 754 755 CPU_FILL(&mask); 756 for (;;) { 757 sched_both(cg, mask, &low, &high); 758 if (low == high || low == -1 || high == -1) 759 break; 760 if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low))) 761 break; 762 /* 763 * If we failed to move any threads determine which cpu 764 * to kick out of the set and try again. 765 */ 766 if (TDQ_CPU(high)->tdq_transferable == 0) 767 CPU_CLR(high, &mask); 768 else 769 CPU_CLR(low, &mask); 770 } 771 772 for (i = 0; i < cg->cg_children; i++) 773 sched_balance_group(&cg->cg_child[i]); 774 } 775 776 static void 777 sched_balance(void) 778 { 779 struct tdq *tdq; 780 781 /* 782 * Select a random time between .5 * balance_interval and 783 * 1.5 * balance_interval. 784 */ 785 balance_ticks = max(balance_interval / 2, 1); 786 balance_ticks += random() % balance_interval; 787 if (smp_started == 0 || rebalance == 0) 788 return; 789 tdq = TDQ_SELF(); 790 TDQ_UNLOCK(tdq); 791 sched_balance_group(cpu_top); 792 TDQ_LOCK(tdq); 793 } 794 795 /* 796 * Lock two thread queues using their address to maintain lock order. 797 */ 798 static void 799 tdq_lock_pair(struct tdq *one, struct tdq *two) 800 { 801 if (one < two) { 802 TDQ_LOCK(one); 803 TDQ_LOCK_FLAGS(two, MTX_DUPOK); 804 } else { 805 TDQ_LOCK(two); 806 TDQ_LOCK_FLAGS(one, MTX_DUPOK); 807 } 808 } 809 810 /* 811 * Unlock two thread queues. Order is not important here. 812 */ 813 static void 814 tdq_unlock_pair(struct tdq *one, struct tdq *two) 815 { 816 TDQ_UNLOCK(one); 817 TDQ_UNLOCK(two); 818 } 819 820 /* 821 * Transfer load between two imbalanced thread queues. 822 */ 823 static int 824 sched_balance_pair(struct tdq *high, struct tdq *low) 825 { 826 int transferable; 827 int high_load; 828 int low_load; 829 int moved; 830 int move; 831 int diff; 832 int i; 833 834 tdq_lock_pair(high, low); 835 transferable = high->tdq_transferable; 836 high_load = high->tdq_load; 837 low_load = low->tdq_load; 838 moved = 0; 839 /* 840 * Determine what the imbalance is and then adjust that to how many 841 * threads we actually have to give up (transferable). 842 */ 843 if (transferable != 0) { 844 diff = high_load - low_load; 845 move = diff / 2; 846 if (diff & 0x1) 847 move++; 848 move = min(move, transferable); 849 for (i = 0; i < move; i++) 850 moved += tdq_move(high, low); 851 /* 852 * IPI the target cpu to force it to reschedule with the new 853 * workload. 854 */ 855 ipi_selected(1 << TDQ_ID(low), IPI_PREEMPT); 856 } 857 tdq_unlock_pair(high, low); 858 return (moved); 859 } 860 861 /* 862 * Move a thread from one thread queue to another. 863 */ 864 static int 865 tdq_move(struct tdq *from, struct tdq *to) 866 { 867 struct td_sched *ts; 868 struct thread *td; 869 struct tdq *tdq; 870 int cpu; 871 872 TDQ_LOCK_ASSERT(from, MA_OWNED); 873 TDQ_LOCK_ASSERT(to, MA_OWNED); 874 875 tdq = from; 876 cpu = TDQ_ID(to); 877 td = tdq_steal(tdq, cpu); 878 if (td == NULL) 879 return (0); 880 ts = td->td_sched; 881 /* 882 * Although the run queue is locked the thread may be blocked. Lock 883 * it to clear this and acquire the run-queue lock. 884 */ 885 thread_lock(td); 886 /* Drop recursive lock on from acquired via thread_lock(). */ 887 TDQ_UNLOCK(from); 888 sched_rem(td); 889 ts->ts_cpu = cpu; 890 td->td_lock = TDQ_LOCKPTR(to); 891 tdq_add(to, td, SRQ_YIELDING); 892 return (1); 893 } 894 895 /* 896 * This tdq has idled. Try to steal a thread from another cpu and switch 897 * to it. 898 */ 899 static int 900 tdq_idled(struct tdq *tdq) 901 { 902 struct cpu_group *cg; 903 struct tdq *steal; 904 cpuset_t mask; 905 int thresh; 906 int cpu; 907 908 if (smp_started == 0 || steal_idle == 0) 909 return (1); 910 CPU_FILL(&mask); 911 CPU_CLR(PCPU_GET(cpuid), &mask); 912 /* We don't want to be preempted while we're iterating. */ 913 spinlock_enter(); 914 for (cg = tdq->tdq_cg; cg != NULL; ) { 915 if ((cg->cg_flags & CG_FLAG_THREAD) == 0) 916 thresh = steal_thresh; 917 else 918 thresh = 1; 919 cpu = sched_highest(cg, mask, thresh); 920 if (cpu == -1) { 921 cg = cg->cg_parent; 922 continue; 923 } 924 steal = TDQ_CPU(cpu); 925 CPU_CLR(cpu, &mask); 926 tdq_lock_pair(tdq, steal); 927 if (steal->tdq_load < thresh || steal->tdq_transferable == 0) { 928 tdq_unlock_pair(tdq, steal); 929 continue; 930 } 931 /* 932 * If a thread was added while interrupts were disabled don't 933 * steal one here. If we fail to acquire one due to affinity 934 * restrictions loop again with this cpu removed from the 935 * set. 936 */ 937 if (tdq->tdq_load == 0 && tdq_move(steal, tdq) == 0) { 938 tdq_unlock_pair(tdq, steal); 939 continue; 940 } 941 spinlock_exit(); 942 TDQ_UNLOCK(steal); 943 mi_switch(SW_VOL | SWT_IDLE, NULL); 944 thread_unlock(curthread); 945 946 return (0); 947 } 948 spinlock_exit(); 949 return (1); 950 } 951 952 /* 953 * Notify a remote cpu of new work. Sends an IPI if criteria are met. 954 */ 955 static void 956 tdq_notify(struct tdq *tdq, struct thread *td) 957 { 958 struct thread *ctd; 959 int pri; 960 int cpu; 961 962 if (tdq->tdq_ipipending) 963 return; 964 cpu = td->td_sched->ts_cpu; 965 pri = td->td_priority; 966 ctd = pcpu_find(cpu)->pc_curthread; 967 if (!sched_shouldpreempt(pri, ctd->td_priority, 1)) 968 return; 969 if (TD_IS_IDLETHREAD(ctd)) { 970 /* 971 * If the MD code has an idle wakeup routine try that before 972 * falling back to IPI. 973 */ 974 if (cpu_idle_wakeup(cpu)) 975 return; 976 } 977 tdq->tdq_ipipending = 1; 978 ipi_selected(1 << cpu, IPI_PREEMPT); 979 } 980 981 /* 982 * Steals load from a timeshare queue. Honors the rotating queue head 983 * index. 984 */ 985 static struct thread * 986 runq_steal_from(struct runq *rq, int cpu, u_char start) 987 { 988 struct rqbits *rqb; 989 struct rqhead *rqh; 990 struct thread *td; 991 int first; 992 int bit; 993 int pri; 994 int i; 995 996 rqb = &rq->rq_status; 997 bit = start & (RQB_BPW -1); 998 pri = 0; 999 first = 0; 1000 again: 1001 for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) { 1002 if (rqb->rqb_bits[i] == 0) 1003 continue; 1004 if (bit != 0) { 1005 for (pri = bit; pri < RQB_BPW; pri++) 1006 if (rqb->rqb_bits[i] & (1ul << pri)) 1007 break; 1008 if (pri >= RQB_BPW) 1009 continue; 1010 } else 1011 pri = RQB_FFS(rqb->rqb_bits[i]); 1012 pri += (i << RQB_L2BPW); 1013 rqh = &rq->rq_queues[pri]; 1014 TAILQ_FOREACH(td, rqh, td_runq) { 1015 if (first && THREAD_CAN_MIGRATE(td) && 1016 THREAD_CAN_SCHED(td, cpu)) 1017 return (td); 1018 first = 1; 1019 } 1020 } 1021 if (start != 0) { 1022 start = 0; 1023 goto again; 1024 } 1025 1026 return (NULL); 1027 } 1028 1029 /* 1030 * Steals load from a standard linear queue. 1031 */ 1032 static struct thread * 1033 runq_steal(struct runq *rq, int cpu) 1034 { 1035 struct rqhead *rqh; 1036 struct rqbits *rqb; 1037 struct thread *td; 1038 int word; 1039 int bit; 1040 1041 rqb = &rq->rq_status; 1042 for (word = 0; word < RQB_LEN; word++) { 1043 if (rqb->rqb_bits[word] == 0) 1044 continue; 1045 for (bit = 0; bit < RQB_BPW; bit++) { 1046 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) 1047 continue; 1048 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; 1049 TAILQ_FOREACH(td, rqh, td_runq) 1050 if (THREAD_CAN_MIGRATE(td) && 1051 THREAD_CAN_SCHED(td, cpu)) 1052 return (td); 1053 } 1054 } 1055 return (NULL); 1056 } 1057 1058 /* 1059 * Attempt to steal a thread in priority order from a thread queue. 1060 */ 1061 static struct thread * 1062 tdq_steal(struct tdq *tdq, int cpu) 1063 { 1064 struct thread *td; 1065 1066 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1067 if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL) 1068 return (td); 1069 if ((td = runq_steal_from(&tdq->tdq_timeshare, 1070 cpu, tdq->tdq_ridx)) != NULL) 1071 return (td); 1072 return (runq_steal(&tdq->tdq_idle, cpu)); 1073 } 1074 1075 /* 1076 * Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the 1077 * current lock and returns with the assigned queue locked. 1078 */ 1079 static inline struct tdq * 1080 sched_setcpu(struct thread *td, int cpu, int flags) 1081 { 1082 1083 struct tdq *tdq; 1084 1085 THREAD_LOCK_ASSERT(td, MA_OWNED); 1086 tdq = TDQ_CPU(cpu); 1087 td->td_sched->ts_cpu = cpu; 1088 /* 1089 * If the lock matches just return the queue. 1090 */ 1091 if (td->td_lock == TDQ_LOCKPTR(tdq)) 1092 return (tdq); 1093 #ifdef notyet 1094 /* 1095 * If the thread isn't running its lockptr is a 1096 * turnstile or a sleepqueue. We can just lock_set without 1097 * blocking. 1098 */ 1099 if (TD_CAN_RUN(td)) { 1100 TDQ_LOCK(tdq); 1101 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 1102 return (tdq); 1103 } 1104 #endif 1105 /* 1106 * The hard case, migration, we need to block the thread first to 1107 * prevent order reversals with other cpus locks. 1108 */ 1109 thread_lock_block(td); 1110 TDQ_LOCK(tdq); 1111 thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); 1112 return (tdq); 1113 } 1114 1115 SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding"); 1116 SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity"); 1117 SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity"); 1118 SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load"); 1119 SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu"); 1120 SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration"); 1121 1122 static int 1123 sched_pickcpu(struct thread *td, int flags) 1124 { 1125 struct cpu_group *cg; 1126 struct td_sched *ts; 1127 struct tdq *tdq; 1128 cpuset_t mask; 1129 int self; 1130 int pri; 1131 int cpu; 1132 1133 self = PCPU_GET(cpuid); 1134 ts = td->td_sched; 1135 if (smp_started == 0) 1136 return (self); 1137 /* 1138 * Don't migrate a running thread from sched_switch(). 1139 */ 1140 if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td)) 1141 return (ts->ts_cpu); 1142 /* 1143 * Prefer to run interrupt threads on the processors that generate 1144 * the interrupt. 1145 */ 1146 if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) && 1147 curthread->td_intr_nesting_level && ts->ts_cpu != self) { 1148 SCHED_STAT_INC(pickcpu_intrbind); 1149 ts->ts_cpu = self; 1150 } 1151 /* 1152 * If the thread can run on the last cpu and the affinity has not 1153 * expired or it is idle run it there. 1154 */ 1155 pri = td->td_priority; 1156 tdq = TDQ_CPU(ts->ts_cpu); 1157 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) { 1158 if (tdq->tdq_lowpri > PRI_MIN_IDLE) { 1159 SCHED_STAT_INC(pickcpu_idle_affinity); 1160 return (ts->ts_cpu); 1161 } 1162 if (SCHED_AFFINITY(ts, CG_SHARE_L2) && tdq->tdq_lowpri > pri) { 1163 SCHED_STAT_INC(pickcpu_affinity); 1164 return (ts->ts_cpu); 1165 } 1166 } 1167 /* 1168 * Search for the highest level in the tree that still has affinity. 1169 */ 1170 cg = NULL; 1171 for (cg = tdq->tdq_cg; cg != NULL; cg = cg->cg_parent) 1172 if (SCHED_AFFINITY(ts, cg->cg_level)) 1173 break; 1174 cpu = -1; 1175 mask = td->td_cpuset->cs_mask; 1176 if (cg) 1177 cpu = sched_lowest(cg, mask, pri); 1178 if (cpu == -1) 1179 cpu = sched_lowest(cpu_top, mask, -1); 1180 /* 1181 * Compare the lowest loaded cpu to current cpu. 1182 */ 1183 if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri && 1184 TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE) { 1185 SCHED_STAT_INC(pickcpu_local); 1186 cpu = self; 1187 } else 1188 SCHED_STAT_INC(pickcpu_lowest); 1189 if (cpu != ts->ts_cpu) 1190 SCHED_STAT_INC(pickcpu_migration); 1191 KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu.")); 1192 return (cpu); 1193 } 1194 #endif 1195 1196 /* 1197 * Pick the highest priority task we have and return it. 1198 */ 1199 static struct thread * 1200 tdq_choose(struct tdq *tdq) 1201 { 1202 struct thread *td; 1203 1204 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 1205 td = runq_choose(&tdq->tdq_realtime); 1206 if (td != NULL) 1207 return (td); 1208 td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); 1209 if (td != NULL) { 1210 KASSERT(td->td_priority >= PRI_MIN_TIMESHARE, 1211 ("tdq_choose: Invalid priority on timeshare queue %d", 1212 td->td_priority)); 1213 return (td); 1214 } 1215 td = runq_choose(&tdq->tdq_idle); 1216 if (td != NULL) { 1217 KASSERT(td->td_priority >= PRI_MIN_IDLE, 1218 ("tdq_choose: Invalid priority on idle queue %d", 1219 td->td_priority)); 1220 return (td); 1221 } 1222 1223 return (NULL); 1224 } 1225 1226 /* 1227 * Initialize a thread queue. 1228 */ 1229 static void 1230 tdq_setup(struct tdq *tdq) 1231 { 1232 1233 if (bootverbose) 1234 printf("ULE: setup cpu %d\n", TDQ_ID(tdq)); 1235 runq_init(&tdq->tdq_realtime); 1236 runq_init(&tdq->tdq_timeshare); 1237 runq_init(&tdq->tdq_idle); 1238 snprintf(tdq->tdq_name, sizeof(tdq->tdq_name), 1239 "sched lock %d", (int)TDQ_ID(tdq)); 1240 mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock", 1241 MTX_SPIN | MTX_RECURSE); 1242 #ifdef KTR 1243 snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname), 1244 "CPU %d load", (int)TDQ_ID(tdq)); 1245 #endif 1246 } 1247 1248 #ifdef SMP 1249 static void 1250 sched_setup_smp(void) 1251 { 1252 struct tdq *tdq; 1253 int i; 1254 1255 cpu_top = smp_topo(); 1256 for (i = 0; i < MAXCPU; i++) { 1257 if (CPU_ABSENT(i)) 1258 continue; 1259 tdq = TDQ_CPU(i); 1260 tdq_setup(tdq); 1261 tdq->tdq_cg = smp_topo_find(cpu_top, i); 1262 if (tdq->tdq_cg == NULL) 1263 panic("Can't find cpu group for %d\n", i); 1264 } 1265 balance_tdq = TDQ_SELF(); 1266 sched_balance(); 1267 } 1268 #endif 1269 1270 /* 1271 * Setup the thread queues and initialize the topology based on MD 1272 * information. 1273 */ 1274 static void 1275 sched_setup(void *dummy) 1276 { 1277 struct tdq *tdq; 1278 1279 tdq = TDQ_SELF(); 1280 #ifdef SMP 1281 sched_setup_smp(); 1282 #else 1283 tdq_setup(tdq); 1284 #endif 1285 /* 1286 * To avoid divide-by-zero, we set realstathz a dummy value 1287 * in case which sched_clock() called before sched_initticks(). 1288 */ 1289 realstathz = hz; 1290 sched_slice = (realstathz/10); /* ~100ms */ 1291 tickincr = 1 << SCHED_TICK_SHIFT; 1292 1293 /* Add thread0's load since it's running. */ 1294 TDQ_LOCK(tdq); 1295 thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1296 tdq_load_add(tdq, &thread0); 1297 tdq->tdq_lowpri = thread0.td_priority; 1298 TDQ_UNLOCK(tdq); 1299 } 1300 1301 /* 1302 * This routine determines the tickincr after stathz and hz are setup. 1303 */ 1304 /* ARGSUSED */ 1305 static void 1306 sched_initticks(void *dummy) 1307 { 1308 int incr; 1309 1310 realstathz = stathz ? stathz : hz; 1311 sched_slice = (realstathz/10); /* ~100ms */ 1312 1313 /* 1314 * tickincr is shifted out by 10 to avoid rounding errors due to 1315 * hz not being evenly divisible by stathz on all platforms. 1316 */ 1317 incr = (hz << SCHED_TICK_SHIFT) / realstathz; 1318 /* 1319 * This does not work for values of stathz that are more than 1320 * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen. 1321 */ 1322 if (incr == 0) 1323 incr = 1; 1324 tickincr = incr; 1325 #ifdef SMP 1326 /* 1327 * Set the default balance interval now that we know 1328 * what realstathz is. 1329 */ 1330 balance_interval = realstathz; 1331 /* 1332 * Set steal thresh to roughly log2(mp_ncpu) but no greater than 4. 1333 * This prevents excess thrashing on large machines and excess idle 1334 * on smaller machines. 1335 */ 1336 steal_thresh = min(fls(mp_ncpus) - 1, 3); 1337 affinity = SCHED_AFFINITY_DEFAULT; 1338 #endif 1339 } 1340 1341 1342 /* 1343 * This is the core of the interactivity algorithm. Determines a score based 1344 * on past behavior. It is the ratio of sleep time to run time scaled to 1345 * a [0, 100] integer. This is the voluntary sleep time of a process, which 1346 * differs from the cpu usage because it does not account for time spent 1347 * waiting on a run-queue. Would be prettier if we had floating point. 1348 */ 1349 static int 1350 sched_interact_score(struct thread *td) 1351 { 1352 struct td_sched *ts; 1353 int div; 1354 1355 ts = td->td_sched; 1356 /* 1357 * The score is only needed if this is likely to be an interactive 1358 * task. Don't go through the expense of computing it if there's 1359 * no chance. 1360 */ 1361 if (sched_interact <= SCHED_INTERACT_HALF && 1362 ts->ts_runtime >= ts->ts_slptime) 1363 return (SCHED_INTERACT_HALF); 1364 1365 if (ts->ts_runtime > ts->ts_slptime) { 1366 div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF); 1367 return (SCHED_INTERACT_HALF + 1368 (SCHED_INTERACT_HALF - (ts->ts_slptime / div))); 1369 } 1370 if (ts->ts_slptime > ts->ts_runtime) { 1371 div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF); 1372 return (ts->ts_runtime / div); 1373 } 1374 /* runtime == slptime */ 1375 if (ts->ts_runtime) 1376 return (SCHED_INTERACT_HALF); 1377 1378 /* 1379 * This can happen if slptime and runtime are 0. 1380 */ 1381 return (0); 1382 1383 } 1384 1385 /* 1386 * Scale the scheduling priority according to the "interactivity" of this 1387 * process. 1388 */ 1389 static void 1390 sched_priority(struct thread *td) 1391 { 1392 int score; 1393 int pri; 1394 1395 if (td->td_pri_class != PRI_TIMESHARE) 1396 return; 1397 /* 1398 * If the score is interactive we place the thread in the realtime 1399 * queue with a priority that is less than kernel and interrupt 1400 * priorities. These threads are not subject to nice restrictions. 1401 * 1402 * Scores greater than this are placed on the normal timeshare queue 1403 * where the priority is partially decided by the most recent cpu 1404 * utilization and the rest is decided by nice value. 1405 * 1406 * The nice value of the process has a linear effect on the calculated 1407 * score. Negative nice values make it easier for a thread to be 1408 * considered interactive. 1409 */ 1410 score = imax(0, sched_interact_score(td) + td->td_proc->p_nice); 1411 if (score < sched_interact) { 1412 pri = PRI_MIN_REALTIME; 1413 pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME) / sched_interact) 1414 * score; 1415 KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME, 1416 ("sched_priority: invalid interactive priority %d score %d", 1417 pri, score)); 1418 } else { 1419 pri = SCHED_PRI_MIN; 1420 if (td->td_sched->ts_ticks) 1421 pri += SCHED_PRI_TICKS(td->td_sched); 1422 pri += SCHED_PRI_NICE(td->td_proc->p_nice); 1423 KASSERT(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE, 1424 ("sched_priority: invalid priority %d: nice %d, " 1425 "ticks %d ftick %d ltick %d tick pri %d", 1426 pri, td->td_proc->p_nice, td->td_sched->ts_ticks, 1427 td->td_sched->ts_ftick, td->td_sched->ts_ltick, 1428 SCHED_PRI_TICKS(td->td_sched))); 1429 } 1430 sched_user_prio(td, pri); 1431 1432 return; 1433 } 1434 1435 /* 1436 * This routine enforces a maximum limit on the amount of scheduling history 1437 * kept. It is called after either the slptime or runtime is adjusted. This 1438 * function is ugly due to integer math. 1439 */ 1440 static void 1441 sched_interact_update(struct thread *td) 1442 { 1443 struct td_sched *ts; 1444 u_int sum; 1445 1446 ts = td->td_sched; 1447 sum = ts->ts_runtime + ts->ts_slptime; 1448 if (sum < SCHED_SLP_RUN_MAX) 1449 return; 1450 /* 1451 * This only happens from two places: 1452 * 1) We have added an unusual amount of run time from fork_exit. 1453 * 2) We have added an unusual amount of sleep time from sched_sleep(). 1454 */ 1455 if (sum > SCHED_SLP_RUN_MAX * 2) { 1456 if (ts->ts_runtime > ts->ts_slptime) { 1457 ts->ts_runtime = SCHED_SLP_RUN_MAX; 1458 ts->ts_slptime = 1; 1459 } else { 1460 ts->ts_slptime = SCHED_SLP_RUN_MAX; 1461 ts->ts_runtime = 1; 1462 } 1463 return; 1464 } 1465 /* 1466 * If we have exceeded by more than 1/5th then the algorithm below 1467 * will not bring us back into range. Dividing by two here forces 1468 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] 1469 */ 1470 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { 1471 ts->ts_runtime /= 2; 1472 ts->ts_slptime /= 2; 1473 return; 1474 } 1475 ts->ts_runtime = (ts->ts_runtime / 5) * 4; 1476 ts->ts_slptime = (ts->ts_slptime / 5) * 4; 1477 } 1478 1479 /* 1480 * Scale back the interactivity history when a child thread is created. The 1481 * history is inherited from the parent but the thread may behave totally 1482 * differently. For example, a shell spawning a compiler process. We want 1483 * to learn that the compiler is behaving badly very quickly. 1484 */ 1485 static void 1486 sched_interact_fork(struct thread *td) 1487 { 1488 int ratio; 1489 int sum; 1490 1491 sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime; 1492 if (sum > SCHED_SLP_RUN_FORK) { 1493 ratio = sum / SCHED_SLP_RUN_FORK; 1494 td->td_sched->ts_runtime /= ratio; 1495 td->td_sched->ts_slptime /= ratio; 1496 } 1497 } 1498 1499 /* 1500 * Called from proc0_init() to setup the scheduler fields. 1501 */ 1502 void 1503 schedinit(void) 1504 { 1505 1506 /* 1507 * Set up the scheduler specific parts of proc0. 1508 */ 1509 proc0.p_sched = NULL; /* XXX */ 1510 thread0.td_sched = &td_sched0; 1511 td_sched0.ts_ltick = ticks; 1512 td_sched0.ts_ftick = ticks; 1513 td_sched0.ts_slice = sched_slice; 1514 } 1515 1516 /* 1517 * This is only somewhat accurate since given many processes of the same 1518 * priority they will switch when their slices run out, which will be 1519 * at most sched_slice stathz ticks. 1520 */ 1521 int 1522 sched_rr_interval(void) 1523 { 1524 1525 /* Convert sched_slice to hz */ 1526 return (hz/(realstathz/sched_slice)); 1527 } 1528 1529 /* 1530 * Update the percent cpu tracking information when it is requested or 1531 * the total history exceeds the maximum. We keep a sliding history of 1532 * tick counts that slowly decays. This is less precise than the 4BSD 1533 * mechanism since it happens with less regular and frequent events. 1534 */ 1535 static void 1536 sched_pctcpu_update(struct td_sched *ts) 1537 { 1538 1539 if (ts->ts_ticks == 0) 1540 return; 1541 if (ticks - (hz / 10) < ts->ts_ltick && 1542 SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX) 1543 return; 1544 /* 1545 * Adjust counters and watermark for pctcpu calc. 1546 */ 1547 if (ts->ts_ltick > ticks - SCHED_TICK_TARG) 1548 ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) * 1549 SCHED_TICK_TARG; 1550 else 1551 ts->ts_ticks = 0; 1552 ts->ts_ltick = ticks; 1553 ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG; 1554 } 1555 1556 /* 1557 * Adjust the priority of a thread. Move it to the appropriate run-queue 1558 * if necessary. This is the back-end for several priority related 1559 * functions. 1560 */ 1561 static void 1562 sched_thread_priority(struct thread *td, u_char prio) 1563 { 1564 struct td_sched *ts; 1565 struct tdq *tdq; 1566 int oldpri; 1567 1568 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio", 1569 "prio:%d", td->td_priority, "new prio:%d", prio, 1570 KTR_ATTR_LINKED, sched_tdname(curthread)); 1571 if (td != curthread && prio > td->td_priority) { 1572 KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread), 1573 "lend prio", "prio:%d", td->td_priority, "new prio:%d", 1574 prio, KTR_ATTR_LINKED, sched_tdname(td)); 1575 } 1576 ts = td->td_sched; 1577 THREAD_LOCK_ASSERT(td, MA_OWNED); 1578 if (td->td_priority == prio) 1579 return; 1580 /* 1581 * If the priority has been elevated due to priority 1582 * propagation, we may have to move ourselves to a new 1583 * queue. This could be optimized to not re-add in some 1584 * cases. 1585 */ 1586 if (TD_ON_RUNQ(td) && prio < td->td_priority) { 1587 sched_rem(td); 1588 td->td_priority = prio; 1589 sched_add(td, SRQ_BORROWING); 1590 return; 1591 } 1592 /* 1593 * If the thread is currently running we may have to adjust the lowpri 1594 * information so other cpus are aware of our current priority. 1595 */ 1596 if (TD_IS_RUNNING(td)) { 1597 tdq = TDQ_CPU(ts->ts_cpu); 1598 oldpri = td->td_priority; 1599 td->td_priority = prio; 1600 if (prio < tdq->tdq_lowpri) 1601 tdq->tdq_lowpri = prio; 1602 else if (tdq->tdq_lowpri == oldpri) 1603 tdq_setlowpri(tdq, td); 1604 return; 1605 } 1606 td->td_priority = prio; 1607 } 1608 1609 /* 1610 * Update a thread's priority when it is lent another thread's 1611 * priority. 1612 */ 1613 void 1614 sched_lend_prio(struct thread *td, u_char prio) 1615 { 1616 1617 td->td_flags |= TDF_BORROWING; 1618 sched_thread_priority(td, prio); 1619 } 1620 1621 /* 1622 * Restore a thread's priority when priority propagation is 1623 * over. The prio argument is the minimum priority the thread 1624 * needs to have to satisfy other possible priority lending 1625 * requests. If the thread's regular priority is less 1626 * important than prio, the thread will keep a priority boost 1627 * of prio. 1628 */ 1629 void 1630 sched_unlend_prio(struct thread *td, u_char prio) 1631 { 1632 u_char base_pri; 1633 1634 if (td->td_base_pri >= PRI_MIN_TIMESHARE && 1635 td->td_base_pri <= PRI_MAX_TIMESHARE) 1636 base_pri = td->td_user_pri; 1637 else 1638 base_pri = td->td_base_pri; 1639 if (prio >= base_pri) { 1640 td->td_flags &= ~TDF_BORROWING; 1641 sched_thread_priority(td, base_pri); 1642 } else 1643 sched_lend_prio(td, prio); 1644 } 1645 1646 /* 1647 * Standard entry for setting the priority to an absolute value. 1648 */ 1649 void 1650 sched_prio(struct thread *td, u_char prio) 1651 { 1652 u_char oldprio; 1653 1654 /* First, update the base priority. */ 1655 td->td_base_pri = prio; 1656 1657 /* 1658 * If the thread is borrowing another thread's priority, don't 1659 * ever lower the priority. 1660 */ 1661 if (td->td_flags & TDF_BORROWING && td->td_priority < prio) 1662 return; 1663 1664 /* Change the real priority. */ 1665 oldprio = td->td_priority; 1666 sched_thread_priority(td, prio); 1667 1668 /* 1669 * If the thread is on a turnstile, then let the turnstile update 1670 * its state. 1671 */ 1672 if (TD_ON_LOCK(td) && oldprio != prio) 1673 turnstile_adjust(td, oldprio); 1674 } 1675 1676 /* 1677 * Set the base user priority, does not effect current running priority. 1678 */ 1679 void 1680 sched_user_prio(struct thread *td, u_char prio) 1681 { 1682 u_char oldprio; 1683 1684 td->td_base_user_pri = prio; 1685 if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio) 1686 return; 1687 oldprio = td->td_user_pri; 1688 td->td_user_pri = prio; 1689 } 1690 1691 void 1692 sched_lend_user_prio(struct thread *td, u_char prio) 1693 { 1694 u_char oldprio; 1695 1696 THREAD_LOCK_ASSERT(td, MA_OWNED); 1697 td->td_flags |= TDF_UBORROWING; 1698 oldprio = td->td_user_pri; 1699 td->td_user_pri = prio; 1700 } 1701 1702 void 1703 sched_unlend_user_prio(struct thread *td, u_char prio) 1704 { 1705 u_char base_pri; 1706 1707 THREAD_LOCK_ASSERT(td, MA_OWNED); 1708 base_pri = td->td_base_user_pri; 1709 if (prio >= base_pri) { 1710 td->td_flags &= ~TDF_UBORROWING; 1711 sched_user_prio(td, base_pri); 1712 } else { 1713 sched_lend_user_prio(td, prio); 1714 } 1715 } 1716 1717 /* 1718 * Block a thread for switching. Similar to thread_block() but does not 1719 * bump the spin count. 1720 */ 1721 static inline struct mtx * 1722 thread_block_switch(struct thread *td) 1723 { 1724 struct mtx *lock; 1725 1726 THREAD_LOCK_ASSERT(td, MA_OWNED); 1727 lock = td->td_lock; 1728 td->td_lock = &blocked_lock; 1729 mtx_unlock_spin(lock); 1730 1731 return (lock); 1732 } 1733 1734 /* 1735 * Handle migration from sched_switch(). This happens only for 1736 * cpu binding. 1737 */ 1738 static struct mtx * 1739 sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) 1740 { 1741 struct tdq *tdn; 1742 1743 tdn = TDQ_CPU(td->td_sched->ts_cpu); 1744 #ifdef SMP 1745 tdq_load_rem(tdq, td); 1746 /* 1747 * Do the lock dance required to avoid LOR. We grab an extra 1748 * spinlock nesting to prevent preemption while we're 1749 * not holding either run-queue lock. 1750 */ 1751 spinlock_enter(); 1752 thread_block_switch(td); /* This releases the lock on tdq. */ 1753 1754 /* 1755 * Acquire both run-queue locks before placing the thread on the new 1756 * run-queue to avoid deadlocks created by placing a thread with a 1757 * blocked lock on the run-queue of a remote processor. The deadlock 1758 * occurs when a third processor attempts to lock the two queues in 1759 * question while the target processor is spinning with its own 1760 * run-queue lock held while waiting for the blocked lock to clear. 1761 */ 1762 tdq_lock_pair(tdn, tdq); 1763 tdq_add(tdn, td, flags); 1764 tdq_notify(tdn, td); 1765 TDQ_UNLOCK(tdn); 1766 spinlock_exit(); 1767 #endif 1768 return (TDQ_LOCKPTR(tdn)); 1769 } 1770 1771 /* 1772 * Release a thread that was blocked with thread_block_switch(). 1773 */ 1774 static inline void 1775 thread_unblock_switch(struct thread *td, struct mtx *mtx) 1776 { 1777 atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock, 1778 (uintptr_t)mtx); 1779 } 1780 1781 /* 1782 * Switch threads. This function has to handle threads coming in while 1783 * blocked for some reason, running, or idle. It also must deal with 1784 * migrating a thread from one queue to another as running threads may 1785 * be assigned elsewhere via binding. 1786 */ 1787 void 1788 sched_switch(struct thread *td, struct thread *newtd, int flags) 1789 { 1790 struct tdq *tdq; 1791 struct td_sched *ts; 1792 struct mtx *mtx; 1793 int srqflag; 1794 int cpuid; 1795 1796 THREAD_LOCK_ASSERT(td, MA_OWNED); 1797 KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument")); 1798 1799 cpuid = PCPU_GET(cpuid); 1800 tdq = TDQ_CPU(cpuid); 1801 ts = td->td_sched; 1802 mtx = td->td_lock; 1803 ts->ts_rltick = ticks; 1804 td->td_lastcpu = td->td_oncpu; 1805 td->td_oncpu = NOCPU; 1806 td->td_flags &= ~TDF_NEEDRESCHED; 1807 td->td_owepreempt = 0; 1808 tdq->tdq_switchcnt++; 1809 /* 1810 * The lock pointer in an idle thread should never change. Reset it 1811 * to CAN_RUN as well. 1812 */ 1813 if (TD_IS_IDLETHREAD(td)) { 1814 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1815 TD_SET_CAN_RUN(td); 1816 } else if (TD_IS_RUNNING(td)) { 1817 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1818 srqflag = (flags & SW_PREEMPT) ? 1819 SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : 1820 SRQ_OURSELF|SRQ_YIELDING; 1821 if (ts->ts_cpu == cpuid) 1822 tdq_runq_add(tdq, td, srqflag); 1823 else 1824 mtx = sched_switch_migrate(tdq, td, srqflag); 1825 } else { 1826 /* This thread must be going to sleep. */ 1827 TDQ_LOCK(tdq); 1828 mtx = thread_block_switch(td); 1829 tdq_load_rem(tdq, td); 1830 } 1831 /* 1832 * We enter here with the thread blocked and assigned to the 1833 * appropriate cpu run-queue or sleep-queue and with the current 1834 * thread-queue locked. 1835 */ 1836 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 1837 newtd = choosethread(); 1838 /* 1839 * Call the MD code to switch contexts if necessary. 1840 */ 1841 if (td != newtd) { 1842 #ifdef HWPMC_HOOKS 1843 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1844 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); 1845 #endif 1846 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 1847 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 1848 1849 #ifdef KDTRACE_HOOKS 1850 /* 1851 * If DTrace has set the active vtime enum to anything 1852 * other than INACTIVE (0), then it should have set the 1853 * function to call. 1854 */ 1855 if (dtrace_vtime_active) 1856 (*dtrace_vtime_switch_func)(newtd); 1857 #endif 1858 1859 cpu_switch(td, newtd, mtx); 1860 /* 1861 * We may return from cpu_switch on a different cpu. However, 1862 * we always return with td_lock pointing to the current cpu's 1863 * run queue lock. 1864 */ 1865 cpuid = PCPU_GET(cpuid); 1866 tdq = TDQ_CPU(cpuid); 1867 lock_profile_obtain_lock_success( 1868 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 1869 #ifdef HWPMC_HOOKS 1870 if (PMC_PROC_IS_USING_PMCS(td->td_proc)) 1871 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); 1872 #endif 1873 } else 1874 thread_unblock_switch(td, mtx); 1875 /* 1876 * Assert that all went well and return. 1877 */ 1878 TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED); 1879 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 1880 td->td_oncpu = cpuid; 1881 } 1882 1883 /* 1884 * Adjust thread priorities as a result of a nice request. 1885 */ 1886 void 1887 sched_nice(struct proc *p, int nice) 1888 { 1889 struct thread *td; 1890 1891 PROC_LOCK_ASSERT(p, MA_OWNED); 1892 1893 p->p_nice = nice; 1894 FOREACH_THREAD_IN_PROC(p, td) { 1895 thread_lock(td); 1896 sched_priority(td); 1897 sched_prio(td, td->td_base_user_pri); 1898 thread_unlock(td); 1899 } 1900 } 1901 1902 /* 1903 * Record the sleep time for the interactivity scorer. 1904 */ 1905 void 1906 sched_sleep(struct thread *td, int prio) 1907 { 1908 1909 THREAD_LOCK_ASSERT(td, MA_OWNED); 1910 1911 td->td_slptick = ticks; 1912 if (TD_IS_SUSPENDED(td) || prio <= PSOCK) 1913 td->td_flags |= TDF_CANSWAP; 1914 if (static_boost == 1 && prio) 1915 sched_prio(td, prio); 1916 else if (static_boost && td->td_priority > static_boost) 1917 sched_prio(td, static_boost); 1918 } 1919 1920 /* 1921 * Schedule a thread to resume execution and record how long it voluntarily 1922 * slept. We also update the pctcpu, interactivity, and priority. 1923 */ 1924 void 1925 sched_wakeup(struct thread *td) 1926 { 1927 struct td_sched *ts; 1928 int slptick; 1929 1930 THREAD_LOCK_ASSERT(td, MA_OWNED); 1931 ts = td->td_sched; 1932 td->td_flags &= ~TDF_CANSWAP; 1933 /* 1934 * If we slept for more than a tick update our interactivity and 1935 * priority. 1936 */ 1937 slptick = td->td_slptick; 1938 td->td_slptick = 0; 1939 if (slptick && slptick != ticks) { 1940 u_int hzticks; 1941 1942 hzticks = (ticks - slptick) << SCHED_TICK_SHIFT; 1943 ts->ts_slptime += hzticks; 1944 sched_interact_update(td); 1945 sched_pctcpu_update(ts); 1946 } 1947 /* Reset the slice value after we sleep. */ 1948 ts->ts_slice = sched_slice; 1949 sched_add(td, SRQ_BORING); 1950 } 1951 1952 /* 1953 * Penalize the parent for creating a new child and initialize the child's 1954 * priority. 1955 */ 1956 void 1957 sched_fork(struct thread *td, struct thread *child) 1958 { 1959 THREAD_LOCK_ASSERT(td, MA_OWNED); 1960 sched_fork_thread(td, child); 1961 /* 1962 * Penalize the parent and child for forking. 1963 */ 1964 sched_interact_fork(child); 1965 sched_priority(child); 1966 td->td_sched->ts_runtime += tickincr; 1967 sched_interact_update(td); 1968 sched_priority(td); 1969 } 1970 1971 /* 1972 * Fork a new thread, may be within the same process. 1973 */ 1974 void 1975 sched_fork_thread(struct thread *td, struct thread *child) 1976 { 1977 struct td_sched *ts; 1978 struct td_sched *ts2; 1979 1980 THREAD_LOCK_ASSERT(td, MA_OWNED); 1981 /* 1982 * Initialize child. 1983 */ 1984 ts = td->td_sched; 1985 ts2 = child->td_sched; 1986 child->td_lock = TDQ_LOCKPTR(TDQ_SELF()); 1987 child->td_cpuset = cpuset_ref(td->td_cpuset); 1988 ts2->ts_cpu = ts->ts_cpu; 1989 ts2->ts_flags = 0; 1990 /* 1991 * Grab our parents cpu estimation information and priority. 1992 */ 1993 ts2->ts_ticks = ts->ts_ticks; 1994 ts2->ts_ltick = ts->ts_ltick; 1995 ts2->ts_incrtick = ts->ts_incrtick; 1996 ts2->ts_ftick = ts->ts_ftick; 1997 child->td_user_pri = td->td_user_pri; 1998 child->td_base_user_pri = td->td_base_user_pri; 1999 /* 2000 * And update interactivity score. 2001 */ 2002 ts2->ts_slptime = ts->ts_slptime; 2003 ts2->ts_runtime = ts->ts_runtime; 2004 ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */ 2005 #ifdef KTR 2006 bzero(ts2->ts_name, sizeof(ts2->ts_name)); 2007 #endif 2008 } 2009 2010 /* 2011 * Adjust the priority class of a thread. 2012 */ 2013 void 2014 sched_class(struct thread *td, int class) 2015 { 2016 2017 THREAD_LOCK_ASSERT(td, MA_OWNED); 2018 if (td->td_pri_class == class) 2019 return; 2020 td->td_pri_class = class; 2021 } 2022 2023 /* 2024 * Return some of the child's priority and interactivity to the parent. 2025 */ 2026 void 2027 sched_exit(struct proc *p, struct thread *child) 2028 { 2029 struct thread *td; 2030 2031 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit", 2032 "prio:td", child->td_priority); 2033 PROC_LOCK_ASSERT(p, MA_OWNED); 2034 td = FIRST_THREAD_IN_PROC(p); 2035 sched_exit_thread(td, child); 2036 } 2037 2038 /* 2039 * Penalize another thread for the time spent on this one. This helps to 2040 * worsen the priority and interactivity of processes which schedule batch 2041 * jobs such as make. This has little effect on the make process itself but 2042 * causes new processes spawned by it to receive worse scores immediately. 2043 */ 2044 void 2045 sched_exit_thread(struct thread *td, struct thread *child) 2046 { 2047 2048 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit", 2049 "prio:td", child->td_priority); 2050 /* 2051 * Give the child's runtime to the parent without returning the 2052 * sleep time as a penalty to the parent. This causes shells that 2053 * launch expensive things to mark their children as expensive. 2054 */ 2055 thread_lock(td); 2056 td->td_sched->ts_runtime += child->td_sched->ts_runtime; 2057 sched_interact_update(td); 2058 sched_priority(td); 2059 thread_unlock(td); 2060 } 2061 2062 void 2063 sched_preempt(struct thread *td) 2064 { 2065 struct tdq *tdq; 2066 2067 thread_lock(td); 2068 tdq = TDQ_SELF(); 2069 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2070 tdq->tdq_ipipending = 0; 2071 if (td->td_priority > tdq->tdq_lowpri) { 2072 int flags; 2073 2074 flags = SW_INVOL | SW_PREEMPT; 2075 if (td->td_critnest > 1) 2076 td->td_owepreempt = 1; 2077 else if (TD_IS_IDLETHREAD(td)) 2078 mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL); 2079 else 2080 mi_switch(flags | SWT_REMOTEPREEMPT, NULL); 2081 } 2082 thread_unlock(td); 2083 } 2084 2085 /* 2086 * Fix priorities on return to user-space. Priorities may be elevated due 2087 * to static priorities in msleep() or similar. 2088 */ 2089 void 2090 sched_userret(struct thread *td) 2091 { 2092 /* 2093 * XXX we cheat slightly on the locking here to avoid locking in 2094 * the usual case. Setting td_priority here is essentially an 2095 * incomplete workaround for not setting it properly elsewhere. 2096 * Now that some interrupt handlers are threads, not setting it 2097 * properly elsewhere can clobber it in the window between setting 2098 * it here and returning to user mode, so don't waste time setting 2099 * it perfectly here. 2100 */ 2101 KASSERT((td->td_flags & TDF_BORROWING) == 0, 2102 ("thread with borrowed priority returning to userland")); 2103 if (td->td_priority != td->td_user_pri) { 2104 thread_lock(td); 2105 td->td_priority = td->td_user_pri; 2106 td->td_base_pri = td->td_user_pri; 2107 tdq_setlowpri(TDQ_SELF(), td); 2108 thread_unlock(td); 2109 } 2110 } 2111 2112 /* 2113 * Handle a stathz tick. This is really only relevant for timeshare 2114 * threads. 2115 */ 2116 void 2117 sched_clock(struct thread *td) 2118 { 2119 struct tdq *tdq; 2120 struct td_sched *ts; 2121 2122 THREAD_LOCK_ASSERT(td, MA_OWNED); 2123 tdq = TDQ_SELF(); 2124 #ifdef SMP 2125 /* 2126 * We run the long term load balancer infrequently on the first cpu. 2127 */ 2128 if (balance_tdq == tdq) { 2129 if (balance_ticks && --balance_ticks == 0) 2130 sched_balance(); 2131 } 2132 #endif 2133 /* 2134 * Save the old switch count so we have a record of the last ticks 2135 * activity. Initialize the new switch count based on our load. 2136 * If there is some activity seed it to reflect that. 2137 */ 2138 tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt; 2139 tdq->tdq_switchcnt = tdq->tdq_load; 2140 /* 2141 * Advance the insert index once for each tick to ensure that all 2142 * threads get a chance to run. 2143 */ 2144 if (tdq->tdq_idx == tdq->tdq_ridx) { 2145 tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; 2146 if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) 2147 tdq->tdq_ridx = tdq->tdq_idx; 2148 } 2149 ts = td->td_sched; 2150 if (td->td_pri_class & PRI_FIFO_BIT) 2151 return; 2152 if (td->td_pri_class == PRI_TIMESHARE) { 2153 /* 2154 * We used a tick; charge it to the thread so 2155 * that we can compute our interactivity. 2156 */ 2157 td->td_sched->ts_runtime += tickincr; 2158 sched_interact_update(td); 2159 sched_priority(td); 2160 } 2161 /* 2162 * We used up one time slice. 2163 */ 2164 if (--ts->ts_slice > 0) 2165 return; 2166 /* 2167 * We're out of time, force a requeue at userret(). 2168 */ 2169 ts->ts_slice = sched_slice; 2170 td->td_flags |= TDF_NEEDRESCHED; 2171 } 2172 2173 /* 2174 * Called once per hz tick. Used for cpu utilization information. This 2175 * is easier than trying to scale based on stathz. 2176 */ 2177 void 2178 sched_tick(void) 2179 { 2180 struct td_sched *ts; 2181 2182 ts = curthread->td_sched; 2183 /* 2184 * Ticks is updated asynchronously on a single cpu. Check here to 2185 * avoid incrementing ts_ticks multiple times in a single tick. 2186 */ 2187 if (ts->ts_incrtick == ticks) 2188 return; 2189 /* Adjust ticks for pctcpu */ 2190 ts->ts_ticks += 1 << SCHED_TICK_SHIFT; 2191 ts->ts_ltick = ticks; 2192 ts->ts_incrtick = ticks; 2193 /* 2194 * Update if we've exceeded our desired tick threshhold by over one 2195 * second. 2196 */ 2197 if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick) 2198 sched_pctcpu_update(ts); 2199 } 2200 2201 /* 2202 * Return whether the current CPU has runnable tasks. Used for in-kernel 2203 * cooperative idle threads. 2204 */ 2205 int 2206 sched_runnable(void) 2207 { 2208 struct tdq *tdq; 2209 int load; 2210 2211 load = 1; 2212 2213 tdq = TDQ_SELF(); 2214 if ((curthread->td_flags & TDF_IDLETD) != 0) { 2215 if (tdq->tdq_load > 0) 2216 goto out; 2217 } else 2218 if (tdq->tdq_load - 1 > 0) 2219 goto out; 2220 load = 0; 2221 out: 2222 return (load); 2223 } 2224 2225 /* 2226 * Choose the highest priority thread to run. The thread is removed from 2227 * the run-queue while running however the load remains. For SMP we set 2228 * the tdq in the global idle bitmask if it idles here. 2229 */ 2230 struct thread * 2231 sched_choose(void) 2232 { 2233 struct thread *td; 2234 struct tdq *tdq; 2235 2236 tdq = TDQ_SELF(); 2237 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2238 td = tdq_choose(tdq); 2239 if (td) { 2240 td->td_sched->ts_ltick = ticks; 2241 tdq_runq_rem(tdq, td); 2242 tdq->tdq_lowpri = td->td_priority; 2243 return (td); 2244 } 2245 tdq->tdq_lowpri = PRI_MAX_IDLE; 2246 return (PCPU_GET(idlethread)); 2247 } 2248 2249 /* 2250 * Set owepreempt if necessary. Preemption never happens directly in ULE, 2251 * we always request it once we exit a critical section. 2252 */ 2253 static inline void 2254 sched_setpreempt(struct thread *td) 2255 { 2256 struct thread *ctd; 2257 int cpri; 2258 int pri; 2259 2260 THREAD_LOCK_ASSERT(curthread, MA_OWNED); 2261 2262 ctd = curthread; 2263 pri = td->td_priority; 2264 cpri = ctd->td_priority; 2265 if (pri < cpri) 2266 ctd->td_flags |= TDF_NEEDRESCHED; 2267 if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) 2268 return; 2269 if (!sched_shouldpreempt(pri, cpri, 0)) 2270 return; 2271 ctd->td_owepreempt = 1; 2272 } 2273 2274 /* 2275 * Add a thread to a thread queue. Select the appropriate runq and add the 2276 * thread to it. This is the internal function called when the tdq is 2277 * predetermined. 2278 */ 2279 void 2280 tdq_add(struct tdq *tdq, struct thread *td, int flags) 2281 { 2282 2283 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2284 KASSERT((td->td_inhibitors == 0), 2285 ("sched_add: trying to run inhibited thread")); 2286 KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), 2287 ("sched_add: bad thread state")); 2288 KASSERT(td->td_flags & TDF_INMEM, 2289 ("sched_add: thread swapped out")); 2290 2291 if (td->td_priority < tdq->tdq_lowpri) 2292 tdq->tdq_lowpri = td->td_priority; 2293 tdq_runq_add(tdq, td, flags); 2294 tdq_load_add(tdq, td); 2295 } 2296 2297 /* 2298 * Select the target thread queue and add a thread to it. Request 2299 * preemption or IPI a remote processor if required. 2300 */ 2301 void 2302 sched_add(struct thread *td, int flags) 2303 { 2304 struct tdq *tdq; 2305 #ifdef SMP 2306 int cpu; 2307 #endif 2308 2309 KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", 2310 "prio:%d", td->td_priority, KTR_ATTR_LINKED, 2311 sched_tdname(curthread)); 2312 KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup", 2313 KTR_ATTR_LINKED, sched_tdname(td)); 2314 THREAD_LOCK_ASSERT(td, MA_OWNED); 2315 /* 2316 * Recalculate the priority before we select the target cpu or 2317 * run-queue. 2318 */ 2319 if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) 2320 sched_priority(td); 2321 #ifdef SMP 2322 /* 2323 * Pick the destination cpu and if it isn't ours transfer to the 2324 * target cpu. 2325 */ 2326 cpu = sched_pickcpu(td, flags); 2327 tdq = sched_setcpu(td, cpu, flags); 2328 tdq_add(tdq, td, flags); 2329 if (cpu != PCPU_GET(cpuid)) { 2330 tdq_notify(tdq, td); 2331 return; 2332 } 2333 #else 2334 tdq = TDQ_SELF(); 2335 TDQ_LOCK(tdq); 2336 /* 2337 * Now that the thread is moving to the run-queue, set the lock 2338 * to the scheduler's lock. 2339 */ 2340 thread_lock_set(td, TDQ_LOCKPTR(tdq)); 2341 tdq_add(tdq, td, flags); 2342 #endif 2343 if (!(flags & SRQ_YIELDING)) 2344 sched_setpreempt(td); 2345 } 2346 2347 /* 2348 * Remove a thread from a run-queue without running it. This is used 2349 * when we're stealing a thread from a remote queue. Otherwise all threads 2350 * exit by calling sched_exit_thread() and sched_throw() themselves. 2351 */ 2352 void 2353 sched_rem(struct thread *td) 2354 { 2355 struct tdq *tdq; 2356 2357 KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem", 2358 "prio:%d", td->td_priority); 2359 tdq = TDQ_CPU(td->td_sched->ts_cpu); 2360 TDQ_LOCK_ASSERT(tdq, MA_OWNED); 2361 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2362 KASSERT(TD_ON_RUNQ(td), 2363 ("sched_rem: thread not on run queue")); 2364 tdq_runq_rem(tdq, td); 2365 tdq_load_rem(tdq, td); 2366 TD_SET_CAN_RUN(td); 2367 if (td->td_priority == tdq->tdq_lowpri) 2368 tdq_setlowpri(tdq, NULL); 2369 } 2370 2371 /* 2372 * Fetch cpu utilization information. Updates on demand. 2373 */ 2374 fixpt_t 2375 sched_pctcpu(struct thread *td) 2376 { 2377 fixpt_t pctcpu; 2378 struct td_sched *ts; 2379 2380 pctcpu = 0; 2381 ts = td->td_sched; 2382 if (ts == NULL) 2383 return (0); 2384 2385 thread_lock(td); 2386 if (ts->ts_ticks) { 2387 int rtick; 2388 2389 sched_pctcpu_update(ts); 2390 /* How many rtick per second ? */ 2391 rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); 2392 pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; 2393 } 2394 thread_unlock(td); 2395 2396 return (pctcpu); 2397 } 2398 2399 /* 2400 * Enforce affinity settings for a thread. Called after adjustments to 2401 * cpumask. 2402 */ 2403 void 2404 sched_affinity(struct thread *td) 2405 { 2406 #ifdef SMP 2407 struct td_sched *ts; 2408 int cpu; 2409 2410 THREAD_LOCK_ASSERT(td, MA_OWNED); 2411 ts = td->td_sched; 2412 if (THREAD_CAN_SCHED(td, ts->ts_cpu)) 2413 return; 2414 if (TD_ON_RUNQ(td)) { 2415 sched_rem(td); 2416 sched_add(td, SRQ_BORING); 2417 return; 2418 } 2419 if (!TD_IS_RUNNING(td)) 2420 return; 2421 td->td_flags |= TDF_NEEDRESCHED; 2422 if (!THREAD_CAN_MIGRATE(td)) 2423 return; 2424 /* 2425 * Assign the new cpu and force a switch before returning to 2426 * userspace. If the target thread is not running locally send 2427 * an ipi to force the issue. 2428 */ 2429 cpu = ts->ts_cpu; 2430 ts->ts_cpu = sched_pickcpu(td, 0); 2431 if (cpu != PCPU_GET(cpuid)) 2432 ipi_selected(1 << cpu, IPI_PREEMPT); 2433 #endif 2434 } 2435 2436 /* 2437 * Bind a thread to a target cpu. 2438 */ 2439 void 2440 sched_bind(struct thread *td, int cpu) 2441 { 2442 struct td_sched *ts; 2443 2444 THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED); 2445 ts = td->td_sched; 2446 if (ts->ts_flags & TSF_BOUND) 2447 sched_unbind(td); 2448 ts->ts_flags |= TSF_BOUND; 2449 sched_pin(); 2450 if (PCPU_GET(cpuid) == cpu) 2451 return; 2452 ts->ts_cpu = cpu; 2453 /* When we return from mi_switch we'll be on the correct cpu. */ 2454 mi_switch(SW_VOL, NULL); 2455 } 2456 2457 /* 2458 * Release a bound thread. 2459 */ 2460 void 2461 sched_unbind(struct thread *td) 2462 { 2463 struct td_sched *ts; 2464 2465 THREAD_LOCK_ASSERT(td, MA_OWNED); 2466 ts = td->td_sched; 2467 if ((ts->ts_flags & TSF_BOUND) == 0) 2468 return; 2469 ts->ts_flags &= ~TSF_BOUND; 2470 sched_unpin(); 2471 } 2472 2473 int 2474 sched_is_bound(struct thread *td) 2475 { 2476 THREAD_LOCK_ASSERT(td, MA_OWNED); 2477 return (td->td_sched->ts_flags & TSF_BOUND); 2478 } 2479 2480 /* 2481 * Basic yield call. 2482 */ 2483 void 2484 sched_relinquish(struct thread *td) 2485 { 2486 thread_lock(td); 2487 mi_switch(SW_VOL | SWT_RELINQUISH, NULL); 2488 thread_unlock(td); 2489 } 2490 2491 /* 2492 * Return the total system load. 2493 */ 2494 int 2495 sched_load(void) 2496 { 2497 #ifdef SMP 2498 int total; 2499 int i; 2500 2501 total = 0; 2502 for (i = 0; i <= mp_maxid; i++) 2503 total += TDQ_CPU(i)->tdq_sysload; 2504 return (total); 2505 #else 2506 return (TDQ_SELF()->tdq_sysload); 2507 #endif 2508 } 2509 2510 int 2511 sched_sizeof_proc(void) 2512 { 2513 return (sizeof(struct proc)); 2514 } 2515 2516 int 2517 sched_sizeof_thread(void) 2518 { 2519 return (sizeof(struct thread) + sizeof(struct td_sched)); 2520 } 2521 2522 #ifdef SMP 2523 #define TDQ_IDLESPIN(tdq) \ 2524 ((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0) 2525 #else 2526 #define TDQ_IDLESPIN(tdq) 1 2527 #endif 2528 2529 /* 2530 * The actual idle process. 2531 */ 2532 void 2533 sched_idletd(void *dummy) 2534 { 2535 struct thread *td; 2536 struct tdq *tdq; 2537 int switchcnt; 2538 int i; 2539 2540 mtx_assert(&Giant, MA_NOTOWNED); 2541 td = curthread; 2542 tdq = TDQ_SELF(); 2543 for (;;) { 2544 #ifdef SMP 2545 if (tdq_idled(tdq) == 0) 2546 continue; 2547 #endif 2548 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2549 /* 2550 * If we're switching very frequently, spin while checking 2551 * for load rather than entering a low power state that 2552 * may require an IPI. However, don't do any busy 2553 * loops while on SMT machines as this simply steals 2554 * cycles from cores doing useful work. 2555 */ 2556 if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) { 2557 for (i = 0; i < sched_idlespins; i++) { 2558 if (tdq->tdq_load) 2559 break; 2560 cpu_spinwait(); 2561 } 2562 } 2563 switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt; 2564 if (tdq->tdq_load == 0) 2565 cpu_idle(switchcnt > 1); 2566 if (tdq->tdq_load) { 2567 thread_lock(td); 2568 mi_switch(SW_VOL | SWT_IDLE, NULL); 2569 thread_unlock(td); 2570 } 2571 } 2572 } 2573 2574 /* 2575 * A CPU is entering for the first time or a thread is exiting. 2576 */ 2577 void 2578 sched_throw(struct thread *td) 2579 { 2580 struct thread *newtd; 2581 struct tdq *tdq; 2582 2583 tdq = TDQ_SELF(); 2584 if (td == NULL) { 2585 /* Correct spinlock nesting and acquire the correct lock. */ 2586 TDQ_LOCK(tdq); 2587 spinlock_exit(); 2588 } else { 2589 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2590 tdq_load_rem(tdq, td); 2591 lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object); 2592 } 2593 KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); 2594 newtd = choosethread(); 2595 TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd; 2596 PCPU_SET(switchtime, cpu_ticks()); 2597 PCPU_SET(switchticks, ticks); 2598 cpu_throw(td, newtd); /* doesn't return */ 2599 } 2600 2601 /* 2602 * This is called from fork_exit(). Just acquire the correct locks and 2603 * let fork do the rest of the work. 2604 */ 2605 void 2606 sched_fork_exit(struct thread *td) 2607 { 2608 struct td_sched *ts; 2609 struct tdq *tdq; 2610 int cpuid; 2611 2612 /* 2613 * Finish setting up thread glue so that it begins execution in a 2614 * non-nested critical section with the scheduler lock held. 2615 */ 2616 cpuid = PCPU_GET(cpuid); 2617 tdq = TDQ_CPU(cpuid); 2618 ts = td->td_sched; 2619 if (TD_IS_IDLETHREAD(td)) 2620 td->td_lock = TDQ_LOCKPTR(tdq); 2621 MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); 2622 td->td_oncpu = cpuid; 2623 TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); 2624 lock_profile_obtain_lock_success( 2625 &TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__); 2626 } 2627 2628 /* 2629 * Create on first use to catch odd startup conditons. 2630 */ 2631 char * 2632 sched_tdname(struct thread *td) 2633 { 2634 #ifdef KTR 2635 struct td_sched *ts; 2636 2637 ts = td->td_sched; 2638 if (ts->ts_name[0] == '\0') 2639 snprintf(ts->ts_name, sizeof(ts->ts_name), 2640 "%s tid %d", td->td_name, td->td_tid); 2641 return (ts->ts_name); 2642 #else 2643 return (td->td_name); 2644 #endif 2645 } 2646 2647 #ifdef SMP 2648 2649 /* 2650 * Build the CPU topology dump string. Is recursively called to collect 2651 * the topology tree. 2652 */ 2653 static int 2654 sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg, 2655 int indent) 2656 { 2657 int i, first; 2658 2659 sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent, 2660 "", indent, cg->cg_level); 2661 sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"0x%x\">", indent, "", 2662 cg->cg_count, cg->cg_mask); 2663 first = TRUE; 2664 for (i = 0; i < MAXCPU; i++) { 2665 if ((cg->cg_mask & (1 << i)) != 0) { 2666 if (!first) 2667 sbuf_printf(sb, ", "); 2668 else 2669 first = FALSE; 2670 sbuf_printf(sb, "%d", i); 2671 } 2672 } 2673 sbuf_printf(sb, "</cpu>\n"); 2674 2675 sbuf_printf(sb, "%*s <flags>", indent, ""); 2676 if (cg->cg_flags != 0) { 2677 if ((cg->cg_flags & CG_FLAG_HTT) != 0) 2678 sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>\n"); 2679 if ((cg->cg_flags & CG_FLAG_SMT) != 0) 2680 sbuf_printf(sb, "<flag name=\"THREAD\">SMT group</flag>\n"); 2681 } 2682 sbuf_printf(sb, "</flags>\n"); 2683 2684 if (cg->cg_children > 0) { 2685 sbuf_printf(sb, "%*s <children>\n", indent, ""); 2686 for (i = 0; i < cg->cg_children; i++) 2687 sysctl_kern_sched_topology_spec_internal(sb, 2688 &cg->cg_child[i], indent+2); 2689 sbuf_printf(sb, "%*s </children>\n", indent, ""); 2690 } 2691 sbuf_printf(sb, "%*s</group>\n", indent, ""); 2692 return (0); 2693 } 2694 2695 /* 2696 * Sysctl handler for retrieving topology dump. It's a wrapper for 2697 * the recursive sysctl_kern_smp_topology_spec_internal(). 2698 */ 2699 static int 2700 sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS) 2701 { 2702 struct sbuf *topo; 2703 int err; 2704 2705 KASSERT(cpu_top != NULL, ("cpu_top isn't initialized")); 2706 2707 topo = sbuf_new(NULL, NULL, 500, SBUF_AUTOEXTEND); 2708 if (topo == NULL) 2709 return (ENOMEM); 2710 2711 sbuf_printf(topo, "<groups>\n"); 2712 err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1); 2713 sbuf_printf(topo, "</groups>\n"); 2714 2715 if (err == 0) { 2716 sbuf_finish(topo); 2717 err = SYSCTL_OUT(req, sbuf_data(topo), sbuf_len(topo)); 2718 } 2719 sbuf_delete(topo); 2720 return (err); 2721 } 2722 #endif 2723 2724 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); 2725 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0, 2726 "Scheduler name"); 2727 SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, 2728 "Slice size for timeshare threads"); 2729 SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, 2730 "Interactivity score threshold"); 2731 SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh, 2732 0,"Min priority for preemption, lower priorities have greater precedence"); 2733 SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 2734 0,"Controls whether static kernel priorities are assigned to sleeping threads."); 2735 SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 2736 0,"Number of times idle will spin waiting for new work."); 2737 SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW, &sched_idlespinthresh, 2738 0,"Threshold before we will permit idle spinning."); 2739 #ifdef SMP 2740 SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0, 2741 "Number of hz ticks to keep thread affinity for"); 2742 SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, 2743 "Enables the long-term load balancer"); 2744 SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW, 2745 &balance_interval, 0, 2746 "Average frequency in stathz ticks to run the long-term balancer"); 2747 SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0, 2748 "Steals work from another hyper-threaded core on idle"); 2749 SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0, 2750 "Attempts to steal work from other cores before idling"); 2751 SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0, 2752 "Minimum load on remote cpu before we'll steal"); 2753 2754 /* Retrieve SMP topology */ 2755 SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING | 2756 CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A", 2757 "XML dump of detected CPU topology"); 2758 #endif 2759 2760 /* ps compat. All cpu percentages from ULE are weighted. */ 2761 static int ccpu = 0; 2762 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 2763