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