1 /*- 2 * Copyright (c) 2002-2003, 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 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/kdb.h> 33 #include <sys/kernel.h> 34 #include <sys/ktr.h> 35 #include <sys/lock.h> 36 #include <sys/mutex.h> 37 #include <sys/proc.h> 38 #include <sys/resource.h> 39 #include <sys/resourcevar.h> 40 #include <sys/sched.h> 41 #include <sys/smp.h> 42 #include <sys/sx.h> 43 #include <sys/sysctl.h> 44 #include <sys/sysproto.h> 45 #include <sys/vmmeter.h> 46 #ifdef KTRACE 47 #include <sys/uio.h> 48 #include <sys/ktrace.h> 49 #endif 50 51 #include <machine/cpu.h> 52 #include <machine/smp.h> 53 54 #define KTR_ULE KTR_NFS 55 56 /* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ 57 /* XXX This is bogus compatability crap for ps */ 58 static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 59 SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 60 61 static void sched_setup(void *dummy); 62 SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL) 63 64 static SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); 65 66 SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ule", 0, 67 "Scheduler name"); 68 69 static int slice_min = 1; 70 SYSCTL_INT(_kern_sched, OID_AUTO, slice_min, CTLFLAG_RW, &slice_min, 0, ""); 71 72 static int slice_max = 10; 73 SYSCTL_INT(_kern_sched, OID_AUTO, slice_max, CTLFLAG_RW, &slice_max, 0, ""); 74 75 int realstathz; 76 int tickincr = 1; 77 78 /* 79 * These datastructures are allocated within their parent datastructure but 80 * are scheduler specific. 81 */ 82 83 struct ke_sched { 84 int ske_slice; 85 struct runq *ske_runq; 86 /* The following variables are only used for pctcpu calculation */ 87 int ske_ltick; /* Last tick that we were running on */ 88 int ske_ftick; /* First tick that we were running on */ 89 int ske_ticks; /* Tick count */ 90 /* CPU that we have affinity for. */ 91 u_char ske_cpu; 92 }; 93 #define ke_slice ke_sched->ske_slice 94 #define ke_runq ke_sched->ske_runq 95 #define ke_ltick ke_sched->ske_ltick 96 #define ke_ftick ke_sched->ske_ftick 97 #define ke_ticks ke_sched->ske_ticks 98 #define ke_cpu ke_sched->ske_cpu 99 #define ke_assign ke_procq.tqe_next 100 101 #define KEF_ASSIGNED KEF_SCHED0 /* KSE is being migrated. */ 102 #define KEF_BOUND KEF_SCHED1 /* KSE can not migrate. */ 103 #define KEF_XFERABLE KEF_SCHED2 /* KSE was added as transferable. */ 104 105 struct kg_sched { 106 int skg_slptime; /* Number of ticks we vol. slept */ 107 int skg_runtime; /* Number of ticks we were running */ 108 }; 109 #define kg_slptime kg_sched->skg_slptime 110 #define kg_runtime kg_sched->skg_runtime 111 112 struct td_sched { 113 int std_slptime; 114 }; 115 #define td_slptime td_sched->std_slptime 116 117 struct td_sched td_sched; 118 struct ke_sched ke_sched; 119 struct kg_sched kg_sched; 120 121 struct ke_sched *kse0_sched = &ke_sched; 122 struct kg_sched *ksegrp0_sched = &kg_sched; 123 struct p_sched *proc0_sched = NULL; 124 struct td_sched *thread0_sched = &td_sched; 125 126 /* 127 * The priority is primarily determined by the interactivity score. Thus, we 128 * give lower(better) priorities to kse groups that use less CPU. The nice 129 * value is then directly added to this to allow nice to have some effect 130 * on latency. 131 * 132 * PRI_RANGE: Total priority range for timeshare threads. 133 * PRI_NRESV: Number of nice values. 134 * PRI_BASE: The start of the dynamic range. 135 */ 136 #define SCHED_PRI_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1) 137 #define SCHED_PRI_NRESV ((PRIO_MAX - PRIO_MIN) + 1) 138 #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) 139 #define SCHED_PRI_BASE (PRI_MIN_TIMESHARE) 140 #define SCHED_PRI_INTERACT(score) \ 141 ((score) * SCHED_PRI_RANGE / SCHED_INTERACT_MAX) 142 143 /* 144 * These determine the interactivity of a process. 145 * 146 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 147 * before throttling back. 148 * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. 149 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 150 * INTERACT_THRESH: Threshhold for placement on the current runq. 151 */ 152 #define SCHED_SLP_RUN_MAX ((hz * 5) << 10) 153 #define SCHED_SLP_RUN_FORK ((hz / 2) << 10) 154 #define SCHED_INTERACT_MAX (100) 155 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 156 #define SCHED_INTERACT_THRESH (30) 157 158 /* 159 * These parameters and macros determine the size of the time slice that is 160 * granted to each thread. 161 * 162 * SLICE_MIN: Minimum time slice granted, in units of ticks. 163 * SLICE_MAX: Maximum time slice granted. 164 * SLICE_RANGE: Range of available time slices scaled by hz. 165 * SLICE_SCALE: The number slices granted per val in the range of [0, max]. 166 * SLICE_NICE: Determine the amount of slice granted to a scaled nice. 167 * SLICE_NTHRESH: The nice cutoff point for slice assignment. 168 */ 169 #define SCHED_SLICE_MIN (slice_min) 170 #define SCHED_SLICE_MAX (slice_max) 171 #define SCHED_SLICE_INTERACTIVE (slice_max) 172 #define SCHED_SLICE_NTHRESH (SCHED_PRI_NHALF - 1) 173 #define SCHED_SLICE_RANGE (SCHED_SLICE_MAX - SCHED_SLICE_MIN + 1) 174 #define SCHED_SLICE_SCALE(val, max) (((val) * SCHED_SLICE_RANGE) / (max)) 175 #define SCHED_SLICE_NICE(nice) \ 176 (SCHED_SLICE_MAX - SCHED_SLICE_SCALE((nice), SCHED_SLICE_NTHRESH)) 177 178 /* 179 * This macro determines whether or not the kse belongs on the current or 180 * next run queue. 181 */ 182 #define SCHED_INTERACTIVE(kg) \ 183 (sched_interact_score(kg) < SCHED_INTERACT_THRESH) 184 #define SCHED_CURR(kg, ke) \ 185 (ke->ke_thread->td_priority < kg->kg_user_pri || \ 186 SCHED_INTERACTIVE(kg)) 187 188 /* 189 * Cpu percentage computation macros and defines. 190 * 191 * SCHED_CPU_TIME: Number of seconds to average the cpu usage across. 192 * SCHED_CPU_TICKS: Number of hz ticks to average the cpu usage across. 193 */ 194 195 #define SCHED_CPU_TIME 10 196 #define SCHED_CPU_TICKS (hz * SCHED_CPU_TIME) 197 198 /* 199 * kseq - per processor runqs and statistics. 200 */ 201 struct kseq { 202 struct runq ksq_idle; /* Queue of IDLE threads. */ 203 struct runq ksq_timeshare[2]; /* Run queues for !IDLE. */ 204 struct runq *ksq_next; /* Next timeshare queue. */ 205 struct runq *ksq_curr; /* Current queue. */ 206 int ksq_load_timeshare; /* Load for timeshare. */ 207 int ksq_load; /* Aggregate load. */ 208 short ksq_nice[SCHED_PRI_NRESV]; /* KSEs in each nice bin. */ 209 short ksq_nicemin; /* Least nice. */ 210 #ifdef SMP 211 int ksq_transferable; 212 LIST_ENTRY(kseq) ksq_siblings; /* Next in kseq group. */ 213 struct kseq_group *ksq_group; /* Our processor group. */ 214 volatile struct kse *ksq_assigned; /* assigned by another CPU. */ 215 #else 216 int ksq_sysload; /* For loadavg, !ITHD load. */ 217 #endif 218 }; 219 220 #ifdef SMP 221 /* 222 * kseq groups are groups of processors which can cheaply share threads. When 223 * one processor in the group goes idle it will check the runqs of the other 224 * processors in its group prior to halting and waiting for an interrupt. 225 * These groups are suitable for SMT (Symetric Multi-Threading) and not NUMA. 226 * In a numa environment we'd want an idle bitmap per group and a two tiered 227 * load balancer. 228 */ 229 struct kseq_group { 230 int ksg_cpus; /* Count of CPUs in this kseq group. */ 231 cpumask_t ksg_cpumask; /* Mask of cpus in this group. */ 232 cpumask_t ksg_idlemask; /* Idle cpus in this group. */ 233 cpumask_t ksg_mask; /* Bit mask for first cpu. */ 234 int ksg_load; /* Total load of this group. */ 235 int ksg_transferable; /* Transferable load of this group. */ 236 LIST_HEAD(, kseq) ksg_members; /* Linked list of all members. */ 237 }; 238 #endif 239 240 /* 241 * One kse queue per processor. 242 */ 243 #ifdef SMP 244 static cpumask_t kseq_idle; 245 static int ksg_maxid; 246 static struct kseq kseq_cpu[MAXCPU]; 247 static struct kseq_group kseq_groups[MAXCPU]; 248 static int bal_tick; 249 static int gbal_tick; 250 251 #define KSEQ_SELF() (&kseq_cpu[PCPU_GET(cpuid)]) 252 #define KSEQ_CPU(x) (&kseq_cpu[(x)]) 253 #define KSEQ_ID(x) ((x) - kseq_cpu) 254 #define KSEQ_GROUP(x) (&kseq_groups[(x)]) 255 #else /* !SMP */ 256 static struct kseq kseq_cpu; 257 258 #define KSEQ_SELF() (&kseq_cpu) 259 #define KSEQ_CPU(x) (&kseq_cpu) 260 #endif 261 262 static void sched_add_internal(struct thread *td, int preemptive); 263 static void sched_slice(struct kse *ke); 264 static void sched_priority(struct ksegrp *kg); 265 static int sched_interact_score(struct ksegrp *kg); 266 static void sched_interact_update(struct ksegrp *kg); 267 static void sched_interact_fork(struct ksegrp *kg); 268 static void sched_pctcpu_update(struct kse *ke); 269 270 /* Operations on per processor queues */ 271 static struct kse * kseq_choose(struct kseq *kseq); 272 static void kseq_setup(struct kseq *kseq); 273 static void kseq_load_add(struct kseq *kseq, struct kse *ke); 274 static void kseq_load_rem(struct kseq *kseq, struct kse *ke); 275 static __inline void kseq_runq_add(struct kseq *kseq, struct kse *ke); 276 static __inline void kseq_runq_rem(struct kseq *kseq, struct kse *ke); 277 static void kseq_nice_add(struct kseq *kseq, int nice); 278 static void kseq_nice_rem(struct kseq *kseq, int nice); 279 void kseq_print(int cpu); 280 #ifdef SMP 281 static int kseq_transfer(struct kseq *ksq, struct kse *ke, int class); 282 static struct kse *runq_steal(struct runq *rq); 283 static void sched_balance(void); 284 static void sched_balance_groups(void); 285 static void sched_balance_group(struct kseq_group *ksg); 286 static void sched_balance_pair(struct kseq *high, struct kseq *low); 287 static void kseq_move(struct kseq *from, int cpu); 288 static int kseq_idled(struct kseq *kseq); 289 static void kseq_notify(struct kse *ke, int cpu); 290 static void kseq_assign(struct kseq *); 291 static struct kse *kseq_steal(struct kseq *kseq, int stealidle); 292 /* 293 * On P4 Xeons the round-robin interrupt delivery is broken. As a result of 294 * this, we can't pin interrupts to the cpu that they were delivered to, 295 * otherwise all ithreads only run on CPU 0. 296 */ 297 #ifdef __i386__ 298 #define KSE_CAN_MIGRATE(ke, class) \ 299 ((ke)->ke_thread->td_pinned == 0 && ((ke)->ke_flags & KEF_BOUND) == 0) 300 #else /* !__i386__ */ 301 #define KSE_CAN_MIGRATE(ke, class) \ 302 ((class) != PRI_ITHD && (ke)->ke_thread->td_pinned == 0 && \ 303 ((ke)->ke_flags & KEF_BOUND) == 0) 304 #endif /* !__i386__ */ 305 #endif 306 307 void 308 kseq_print(int cpu) 309 { 310 struct kseq *kseq; 311 int i; 312 313 kseq = KSEQ_CPU(cpu); 314 315 printf("kseq:\n"); 316 printf("\tload: %d\n", kseq->ksq_load); 317 printf("\tload TIMESHARE: %d\n", kseq->ksq_load_timeshare); 318 #ifdef SMP 319 printf("\tload transferable: %d\n", kseq->ksq_transferable); 320 #endif 321 printf("\tnicemin:\t%d\n", kseq->ksq_nicemin); 322 printf("\tnice counts:\n"); 323 for (i = 0; i < SCHED_PRI_NRESV; i++) 324 if (kseq->ksq_nice[i]) 325 printf("\t\t%d = %d\n", 326 i - SCHED_PRI_NHALF, kseq->ksq_nice[i]); 327 } 328 329 static __inline void 330 kseq_runq_add(struct kseq *kseq, struct kse *ke) 331 { 332 #ifdef SMP 333 if (KSE_CAN_MIGRATE(ke, PRI_BASE(ke->ke_ksegrp->kg_pri_class))) { 334 kseq->ksq_transferable++; 335 kseq->ksq_group->ksg_transferable++; 336 ke->ke_flags |= KEF_XFERABLE; 337 } 338 #endif 339 runq_add(ke->ke_runq, ke); 340 } 341 342 static __inline void 343 kseq_runq_rem(struct kseq *kseq, struct kse *ke) 344 { 345 #ifdef SMP 346 if (ke->ke_flags & KEF_XFERABLE) { 347 kseq->ksq_transferable--; 348 kseq->ksq_group->ksg_transferable--; 349 ke->ke_flags &= ~KEF_XFERABLE; 350 } 351 #endif 352 runq_remove(ke->ke_runq, ke); 353 } 354 355 static void 356 kseq_load_add(struct kseq *kseq, struct kse *ke) 357 { 358 int class; 359 mtx_assert(&sched_lock, MA_OWNED); 360 class = PRI_BASE(ke->ke_ksegrp->kg_pri_class); 361 if (class == PRI_TIMESHARE) 362 kseq->ksq_load_timeshare++; 363 kseq->ksq_load++; 364 if (class != PRI_ITHD && (ke->ke_proc->p_flag & P_NOLOAD) == 0) 365 #ifdef SMP 366 kseq->ksq_group->ksg_load++; 367 #else 368 kseq->ksq_sysload++; 369 #endif 370 if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) 371 CTR6(KTR_ULE, 372 "Add kse %p to %p (slice: %d, pri: %d, nice: %d(%d))", 373 ke, ke->ke_runq, ke->ke_slice, ke->ke_thread->td_priority, 374 ke->ke_proc->p_nice, kseq->ksq_nicemin); 375 if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) 376 kseq_nice_add(kseq, ke->ke_proc->p_nice); 377 } 378 379 static void 380 kseq_load_rem(struct kseq *kseq, struct kse *ke) 381 { 382 int class; 383 mtx_assert(&sched_lock, MA_OWNED); 384 class = PRI_BASE(ke->ke_ksegrp->kg_pri_class); 385 if (class == PRI_TIMESHARE) 386 kseq->ksq_load_timeshare--; 387 if (class != PRI_ITHD && (ke->ke_proc->p_flag & P_NOLOAD) == 0) 388 #ifdef SMP 389 kseq->ksq_group->ksg_load--; 390 #else 391 kseq->ksq_sysload--; 392 #endif 393 kseq->ksq_load--; 394 ke->ke_runq = NULL; 395 if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) 396 kseq_nice_rem(kseq, ke->ke_proc->p_nice); 397 } 398 399 static void 400 kseq_nice_add(struct kseq *kseq, int nice) 401 { 402 mtx_assert(&sched_lock, MA_OWNED); 403 /* Normalize to zero. */ 404 kseq->ksq_nice[nice + SCHED_PRI_NHALF]++; 405 if (nice < kseq->ksq_nicemin || kseq->ksq_load_timeshare == 1) 406 kseq->ksq_nicemin = nice; 407 } 408 409 static void 410 kseq_nice_rem(struct kseq *kseq, int nice) 411 { 412 int n; 413 414 mtx_assert(&sched_lock, MA_OWNED); 415 /* Normalize to zero. */ 416 n = nice + SCHED_PRI_NHALF; 417 kseq->ksq_nice[n]--; 418 KASSERT(kseq->ksq_nice[n] >= 0, ("Negative nice count.")); 419 420 /* 421 * If this wasn't the smallest nice value or there are more in 422 * this bucket we can just return. Otherwise we have to recalculate 423 * the smallest nice. 424 */ 425 if (nice != kseq->ksq_nicemin || 426 kseq->ksq_nice[n] != 0 || 427 kseq->ksq_load_timeshare == 0) 428 return; 429 430 for (; n < SCHED_PRI_NRESV; n++) 431 if (kseq->ksq_nice[n]) { 432 kseq->ksq_nicemin = n - SCHED_PRI_NHALF; 433 return; 434 } 435 } 436 437 #ifdef SMP 438 /* 439 * sched_balance is a simple CPU load balancing algorithm. It operates by 440 * finding the least loaded and most loaded cpu and equalizing their load 441 * by migrating some processes. 442 * 443 * Dealing only with two CPUs at a time has two advantages. Firstly, most 444 * installations will only have 2 cpus. Secondly, load balancing too much at 445 * once can have an unpleasant effect on the system. The scheduler rarely has 446 * enough information to make perfect decisions. So this algorithm chooses 447 * algorithm simplicity and more gradual effects on load in larger systems. 448 * 449 * It could be improved by considering the priorities and slices assigned to 450 * each task prior to balancing them. There are many pathological cases with 451 * any approach and so the semi random algorithm below may work as well as any. 452 * 453 */ 454 static void 455 sched_balance(void) 456 { 457 struct kseq_group *high; 458 struct kseq_group *low; 459 struct kseq_group *ksg; 460 int cnt; 461 int i; 462 463 if (smp_started == 0) 464 goto out; 465 low = high = NULL; 466 i = random() % (ksg_maxid + 1); 467 for (cnt = 0; cnt <= ksg_maxid; cnt++) { 468 ksg = KSEQ_GROUP(i); 469 /* 470 * Find the CPU with the highest load that has some 471 * threads to transfer. 472 */ 473 if ((high == NULL || ksg->ksg_load > high->ksg_load) 474 && ksg->ksg_transferable) 475 high = ksg; 476 if (low == NULL || ksg->ksg_load < low->ksg_load) 477 low = ksg; 478 if (++i > ksg_maxid) 479 i = 0; 480 } 481 if (low != NULL && high != NULL && high != low) 482 sched_balance_pair(LIST_FIRST(&high->ksg_members), 483 LIST_FIRST(&low->ksg_members)); 484 out: 485 bal_tick = ticks + (random() % (hz * 2)); 486 } 487 488 static void 489 sched_balance_groups(void) 490 { 491 int i; 492 493 mtx_assert(&sched_lock, MA_OWNED); 494 if (smp_started) 495 for (i = 0; i <= ksg_maxid; i++) 496 sched_balance_group(KSEQ_GROUP(i)); 497 gbal_tick = ticks + (random() % (hz * 2)); 498 } 499 500 static void 501 sched_balance_group(struct kseq_group *ksg) 502 { 503 struct kseq *kseq; 504 struct kseq *high; 505 struct kseq *low; 506 int load; 507 508 if (ksg->ksg_transferable == 0) 509 return; 510 low = NULL; 511 high = NULL; 512 LIST_FOREACH(kseq, &ksg->ksg_members, ksq_siblings) { 513 load = kseq->ksq_load; 514 if (high == NULL || load > high->ksq_load) 515 high = kseq; 516 if (low == NULL || load < low->ksq_load) 517 low = kseq; 518 } 519 if (high != NULL && low != NULL && high != low) 520 sched_balance_pair(high, low); 521 } 522 523 static void 524 sched_balance_pair(struct kseq *high, struct kseq *low) 525 { 526 int transferable; 527 int high_load; 528 int low_load; 529 int move; 530 int diff; 531 int i; 532 533 /* 534 * If we're transfering within a group we have to use this specific 535 * kseq's transferable count, otherwise we can steal from other members 536 * of the group. 537 */ 538 if (high->ksq_group == low->ksq_group) { 539 transferable = high->ksq_transferable; 540 high_load = high->ksq_load; 541 low_load = low->ksq_load; 542 } else { 543 transferable = high->ksq_group->ksg_transferable; 544 high_load = high->ksq_group->ksg_load; 545 low_load = low->ksq_group->ksg_load; 546 } 547 if (transferable == 0) 548 return; 549 /* 550 * Determine what the imbalance is and then adjust that to how many 551 * kses we actually have to give up (transferable). 552 */ 553 diff = high_load - low_load; 554 move = diff / 2; 555 if (diff & 0x1) 556 move++; 557 move = min(move, transferable); 558 for (i = 0; i < move; i++) 559 kseq_move(high, KSEQ_ID(low)); 560 return; 561 } 562 563 static void 564 kseq_move(struct kseq *from, int cpu) 565 { 566 struct kseq *kseq; 567 struct kseq *to; 568 struct kse *ke; 569 570 kseq = from; 571 to = KSEQ_CPU(cpu); 572 ke = kseq_steal(kseq, 1); 573 if (ke == NULL) { 574 struct kseq_group *ksg; 575 576 ksg = kseq->ksq_group; 577 LIST_FOREACH(kseq, &ksg->ksg_members, ksq_siblings) { 578 if (kseq == from || kseq->ksq_transferable == 0) 579 continue; 580 ke = kseq_steal(kseq, 1); 581 break; 582 } 583 if (ke == NULL) 584 panic("kseq_move: No KSEs available with a " 585 "transferable count of %d\n", 586 ksg->ksg_transferable); 587 } 588 if (kseq == to) 589 return; 590 ke->ke_state = KES_THREAD; 591 kseq_runq_rem(kseq, ke); 592 kseq_load_rem(kseq, ke); 593 kseq_notify(ke, cpu); 594 } 595 596 static int 597 kseq_idled(struct kseq *kseq) 598 { 599 struct kseq_group *ksg; 600 struct kseq *steal; 601 struct kse *ke; 602 603 ksg = kseq->ksq_group; 604 /* 605 * If we're in a cpu group, try and steal kses from another cpu in 606 * the group before idling. 607 */ 608 if (ksg->ksg_cpus > 1 && ksg->ksg_transferable) { 609 LIST_FOREACH(steal, &ksg->ksg_members, ksq_siblings) { 610 if (steal == kseq || steal->ksq_transferable == 0) 611 continue; 612 ke = kseq_steal(steal, 0); 613 if (ke == NULL) 614 continue; 615 ke->ke_state = KES_THREAD; 616 kseq_runq_rem(steal, ke); 617 kseq_load_rem(steal, ke); 618 ke->ke_cpu = PCPU_GET(cpuid); 619 sched_add_internal(ke->ke_thread, 0); 620 return (0); 621 } 622 } 623 /* 624 * We only set the idled bit when all of the cpus in the group are 625 * idle. Otherwise we could get into a situation where a KSE bounces 626 * back and forth between two idle cores on seperate physical CPUs. 627 */ 628 ksg->ksg_idlemask |= PCPU_GET(cpumask); 629 if (ksg->ksg_idlemask != ksg->ksg_cpumask) 630 return (1); 631 atomic_set_int(&kseq_idle, ksg->ksg_mask); 632 return (1); 633 } 634 635 static void 636 kseq_assign(struct kseq *kseq) 637 { 638 struct kse *nke; 639 struct kse *ke; 640 641 do { 642 *(volatile struct kse **)&ke = kseq->ksq_assigned; 643 } while(!atomic_cmpset_ptr(&kseq->ksq_assigned, ke, NULL)); 644 for (; ke != NULL; ke = nke) { 645 nke = ke->ke_assign; 646 ke->ke_flags &= ~KEF_ASSIGNED; 647 sched_add_internal(ke->ke_thread, 0); 648 } 649 } 650 651 static void 652 kseq_notify(struct kse *ke, int cpu) 653 { 654 struct kseq *kseq; 655 struct thread *td; 656 struct pcpu *pcpu; 657 int prio; 658 659 ke->ke_cpu = cpu; 660 ke->ke_flags |= KEF_ASSIGNED; 661 prio = ke->ke_thread->td_priority; 662 663 kseq = KSEQ_CPU(cpu); 664 665 /* 666 * Place a KSE on another cpu's queue and force a resched. 667 */ 668 do { 669 *(volatile struct kse **)&ke->ke_assign = kseq->ksq_assigned; 670 } while(!atomic_cmpset_ptr(&kseq->ksq_assigned, ke->ke_assign, ke)); 671 /* 672 * Without sched_lock we could lose a race where we set NEEDRESCHED 673 * on a thread that is switched out before the IPI is delivered. This 674 * would lead us to miss the resched. This will be a problem once 675 * sched_lock is pushed down. 676 */ 677 pcpu = pcpu_find(cpu); 678 td = pcpu->pc_curthread; 679 if (ke->ke_thread->td_priority < td->td_priority || 680 td == pcpu->pc_idlethread) { 681 td->td_flags |= TDF_NEEDRESCHED; 682 ipi_selected(1 << cpu, IPI_AST); 683 } 684 } 685 686 static struct kse * 687 runq_steal(struct runq *rq) 688 { 689 struct rqhead *rqh; 690 struct rqbits *rqb; 691 struct kse *ke; 692 int word; 693 int bit; 694 695 mtx_assert(&sched_lock, MA_OWNED); 696 rqb = &rq->rq_status; 697 for (word = 0; word < RQB_LEN; word++) { 698 if (rqb->rqb_bits[word] == 0) 699 continue; 700 for (bit = 0; bit < RQB_BPW; bit++) { 701 if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) 702 continue; 703 rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; 704 TAILQ_FOREACH(ke, rqh, ke_procq) { 705 if (KSE_CAN_MIGRATE(ke, 706 PRI_BASE(ke->ke_ksegrp->kg_pri_class))) 707 return (ke); 708 } 709 } 710 } 711 return (NULL); 712 } 713 714 static struct kse * 715 kseq_steal(struct kseq *kseq, int stealidle) 716 { 717 struct kse *ke; 718 719 /* 720 * Steal from next first to try to get a non-interactive task that 721 * may not have run for a while. 722 */ 723 if ((ke = runq_steal(kseq->ksq_next)) != NULL) 724 return (ke); 725 if ((ke = runq_steal(kseq->ksq_curr)) != NULL) 726 return (ke); 727 if (stealidle) 728 return (runq_steal(&kseq->ksq_idle)); 729 return (NULL); 730 } 731 732 int 733 kseq_transfer(struct kseq *kseq, struct kse *ke, int class) 734 { 735 struct kseq_group *ksg; 736 int cpu; 737 738 if (smp_started == 0) 739 return (0); 740 cpu = 0; 741 /* 742 * If our load exceeds a certain threshold we should attempt to 743 * reassign this thread. The first candidate is the cpu that 744 * originally ran the thread. If it is idle, assign it there, 745 * otherwise, pick an idle cpu. 746 * 747 * The threshold at which we start to reassign kses has a large impact 748 * on the overall performance of the system. Tuned too high and 749 * some CPUs may idle. Too low and there will be excess migration 750 * and context switches. 751 */ 752 ksg = kseq->ksq_group; 753 if (ksg->ksg_load > ksg->ksg_cpus && kseq_idle) { 754 ksg = KSEQ_CPU(ke->ke_cpu)->ksq_group; 755 if (kseq_idle & ksg->ksg_mask) { 756 cpu = ffs(ksg->ksg_idlemask); 757 if (cpu) 758 goto migrate; 759 } 760 /* 761 * Multiple cpus could find this bit simultaneously 762 * but the race shouldn't be terrible. 763 */ 764 cpu = ffs(kseq_idle); 765 if (cpu) 766 goto migrate; 767 } 768 /* 769 * If another cpu in this group has idled, assign a thread over 770 * to them after checking to see if there are idled groups. 771 */ 772 ksg = kseq->ksq_group; 773 if (ksg->ksg_idlemask) { 774 cpu = ffs(ksg->ksg_idlemask); 775 if (cpu) 776 goto migrate; 777 } 778 /* 779 * No new CPU was found. 780 */ 781 return (0); 782 migrate: 783 /* 784 * Now that we've found an idle CPU, migrate the thread. 785 */ 786 cpu--; 787 ke->ke_runq = NULL; 788 kseq_notify(ke, cpu); 789 790 return (1); 791 } 792 793 #endif /* SMP */ 794 795 /* 796 * Pick the highest priority task we have and return it. 797 */ 798 799 static struct kse * 800 kseq_choose(struct kseq *kseq) 801 { 802 struct kse *ke; 803 struct runq *swap; 804 805 mtx_assert(&sched_lock, MA_OWNED); 806 swap = NULL; 807 808 for (;;) { 809 ke = runq_choose(kseq->ksq_curr); 810 if (ke == NULL) { 811 /* 812 * We already swapped once and didn't get anywhere. 813 */ 814 if (swap) 815 break; 816 swap = kseq->ksq_curr; 817 kseq->ksq_curr = kseq->ksq_next; 818 kseq->ksq_next = swap; 819 continue; 820 } 821 /* 822 * If we encounter a slice of 0 the kse is in a 823 * TIMESHARE kse group and its nice was too far out 824 * of the range that receives slices. 825 */ 826 if (ke->ke_slice == 0) { 827 runq_remove(ke->ke_runq, ke); 828 sched_slice(ke); 829 ke->ke_runq = kseq->ksq_next; 830 runq_add(ke->ke_runq, ke); 831 continue; 832 } 833 return (ke); 834 } 835 836 return (runq_choose(&kseq->ksq_idle)); 837 } 838 839 static void 840 kseq_setup(struct kseq *kseq) 841 { 842 runq_init(&kseq->ksq_timeshare[0]); 843 runq_init(&kseq->ksq_timeshare[1]); 844 runq_init(&kseq->ksq_idle); 845 kseq->ksq_curr = &kseq->ksq_timeshare[0]; 846 kseq->ksq_next = &kseq->ksq_timeshare[1]; 847 kseq->ksq_load = 0; 848 kseq->ksq_load_timeshare = 0; 849 } 850 851 static void 852 sched_setup(void *dummy) 853 { 854 #ifdef SMP 855 int balance_groups; 856 int i; 857 #endif 858 859 slice_min = (hz/100); /* 10ms */ 860 slice_max = (hz/7); /* ~140ms */ 861 862 #ifdef SMP 863 balance_groups = 0; 864 /* 865 * Initialize the kseqs. 866 */ 867 for (i = 0; i < MAXCPU; i++) { 868 struct kseq *ksq; 869 870 ksq = &kseq_cpu[i]; 871 ksq->ksq_assigned = NULL; 872 kseq_setup(&kseq_cpu[i]); 873 } 874 if (smp_topology == NULL) { 875 struct kseq_group *ksg; 876 struct kseq *ksq; 877 878 for (i = 0; i < MAXCPU; i++) { 879 ksq = &kseq_cpu[i]; 880 ksg = &kseq_groups[i]; 881 /* 882 * Setup a kseq group with one member. 883 */ 884 ksq->ksq_transferable = 0; 885 ksq->ksq_group = ksg; 886 ksg->ksg_cpus = 1; 887 ksg->ksg_idlemask = 0; 888 ksg->ksg_cpumask = ksg->ksg_mask = 1 << i; 889 ksg->ksg_load = 0; 890 ksg->ksg_transferable = 0; 891 LIST_INIT(&ksg->ksg_members); 892 LIST_INSERT_HEAD(&ksg->ksg_members, ksq, ksq_siblings); 893 } 894 } else { 895 struct kseq_group *ksg; 896 struct cpu_group *cg; 897 int j; 898 899 for (i = 0; i < smp_topology->ct_count; i++) { 900 cg = &smp_topology->ct_group[i]; 901 ksg = &kseq_groups[i]; 902 /* 903 * Initialize the group. 904 */ 905 ksg->ksg_idlemask = 0; 906 ksg->ksg_load = 0; 907 ksg->ksg_transferable = 0; 908 ksg->ksg_cpus = cg->cg_count; 909 ksg->ksg_cpumask = cg->cg_mask; 910 LIST_INIT(&ksg->ksg_members); 911 /* 912 * Find all of the group members and add them. 913 */ 914 for (j = 0; j < MAXCPU; j++) { 915 if ((cg->cg_mask & (1 << j)) != 0) { 916 if (ksg->ksg_mask == 0) 917 ksg->ksg_mask = 1 << j; 918 kseq_cpu[j].ksq_transferable = 0; 919 kseq_cpu[j].ksq_group = ksg; 920 LIST_INSERT_HEAD(&ksg->ksg_members, 921 &kseq_cpu[j], ksq_siblings); 922 } 923 } 924 if (ksg->ksg_cpus > 1) 925 balance_groups = 1; 926 } 927 ksg_maxid = smp_topology->ct_count - 1; 928 } 929 /* 930 * Stagger the group and global load balancer so they do not 931 * interfere with each other. 932 */ 933 bal_tick = ticks + hz; 934 if (balance_groups) 935 gbal_tick = ticks + (hz / 2); 936 #else 937 kseq_setup(KSEQ_SELF()); 938 #endif 939 mtx_lock_spin(&sched_lock); 940 kseq_load_add(KSEQ_SELF(), &kse0); 941 mtx_unlock_spin(&sched_lock); 942 } 943 944 /* 945 * Scale the scheduling priority according to the "interactivity" of this 946 * process. 947 */ 948 static void 949 sched_priority(struct ksegrp *kg) 950 { 951 int pri; 952 953 if (kg->kg_pri_class != PRI_TIMESHARE) 954 return; 955 956 pri = SCHED_PRI_INTERACT(sched_interact_score(kg)); 957 pri += SCHED_PRI_BASE; 958 pri += kg->kg_proc->p_nice; 959 960 if (pri > PRI_MAX_TIMESHARE) 961 pri = PRI_MAX_TIMESHARE; 962 else if (pri < PRI_MIN_TIMESHARE) 963 pri = PRI_MIN_TIMESHARE; 964 965 kg->kg_user_pri = pri; 966 967 return; 968 } 969 970 /* 971 * Calculate a time slice based on the properties of the kseg and the runq 972 * that we're on. This is only for PRI_TIMESHARE ksegrps. 973 */ 974 static void 975 sched_slice(struct kse *ke) 976 { 977 struct kseq *kseq; 978 struct ksegrp *kg; 979 980 kg = ke->ke_ksegrp; 981 kseq = KSEQ_CPU(ke->ke_cpu); 982 983 /* 984 * Rationale: 985 * KSEs in interactive ksegs get a minimal slice so that we 986 * quickly notice if it abuses its advantage. 987 * 988 * KSEs in non-interactive ksegs are assigned a slice that is 989 * based on the ksegs nice value relative to the least nice kseg 990 * on the run queue for this cpu. 991 * 992 * If the KSE is less nice than all others it gets the maximum 993 * slice and other KSEs will adjust their slice relative to 994 * this when they first expire. 995 * 996 * There is 20 point window that starts relative to the least 997 * nice kse on the run queue. Slice size is determined by 998 * the kse distance from the last nice ksegrp. 999 * 1000 * If the kse is outside of the window it will get no slice 1001 * and will be reevaluated each time it is selected on the 1002 * run queue. The exception to this is nice 0 ksegs when 1003 * a nice -20 is running. They are always granted a minimum 1004 * slice. 1005 */ 1006 if (!SCHED_INTERACTIVE(kg)) { 1007 int nice; 1008 1009 nice = kg->kg_proc->p_nice + (0 - kseq->ksq_nicemin); 1010 if (kseq->ksq_load_timeshare == 0 || 1011 kg->kg_proc->p_nice < kseq->ksq_nicemin) 1012 ke->ke_slice = SCHED_SLICE_MAX; 1013 else if (nice <= SCHED_SLICE_NTHRESH) 1014 ke->ke_slice = SCHED_SLICE_NICE(nice); 1015 else if (kg->kg_proc->p_nice == 0) 1016 ke->ke_slice = SCHED_SLICE_MIN; 1017 else 1018 ke->ke_slice = 0; 1019 } else 1020 ke->ke_slice = SCHED_SLICE_INTERACTIVE; 1021 1022 CTR6(KTR_ULE, 1023 "Sliced %p(%d) (nice: %d, nicemin: %d, load: %d, interactive: %d)", 1024 ke, ke->ke_slice, kg->kg_proc->p_nice, kseq->ksq_nicemin, 1025 kseq->ksq_load_timeshare, SCHED_INTERACTIVE(kg)); 1026 1027 return; 1028 } 1029 1030 /* 1031 * This routine enforces a maximum limit on the amount of scheduling history 1032 * kept. It is called after either the slptime or runtime is adjusted. 1033 * This routine will not operate correctly when slp or run times have been 1034 * adjusted to more than double their maximum. 1035 */ 1036 static void 1037 sched_interact_update(struct ksegrp *kg) 1038 { 1039 int sum; 1040 1041 sum = kg->kg_runtime + kg->kg_slptime; 1042 if (sum < SCHED_SLP_RUN_MAX) 1043 return; 1044 /* 1045 * If we have exceeded by more than 1/5th then the algorithm below 1046 * will not bring us back into range. Dividing by two here forces 1047 * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] 1048 */ 1049 if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { 1050 kg->kg_runtime /= 2; 1051 kg->kg_slptime /= 2; 1052 return; 1053 } 1054 kg->kg_runtime = (kg->kg_runtime / 5) * 4; 1055 kg->kg_slptime = (kg->kg_slptime / 5) * 4; 1056 } 1057 1058 static void 1059 sched_interact_fork(struct ksegrp *kg) 1060 { 1061 int ratio; 1062 int sum; 1063 1064 sum = kg->kg_runtime + kg->kg_slptime; 1065 if (sum > SCHED_SLP_RUN_FORK) { 1066 ratio = sum / SCHED_SLP_RUN_FORK; 1067 kg->kg_runtime /= ratio; 1068 kg->kg_slptime /= ratio; 1069 } 1070 } 1071 1072 static int 1073 sched_interact_score(struct ksegrp *kg) 1074 { 1075 int div; 1076 1077 if (kg->kg_runtime > kg->kg_slptime) { 1078 div = max(1, kg->kg_runtime / SCHED_INTERACT_HALF); 1079 return (SCHED_INTERACT_HALF + 1080 (SCHED_INTERACT_HALF - (kg->kg_slptime / div))); 1081 } if (kg->kg_slptime > kg->kg_runtime) { 1082 div = max(1, kg->kg_slptime / SCHED_INTERACT_HALF); 1083 return (kg->kg_runtime / div); 1084 } 1085 1086 /* 1087 * This can happen if slptime and runtime are 0. 1088 */ 1089 return (0); 1090 1091 } 1092 1093 /* 1094 * This is only somewhat accurate since given many processes of the same 1095 * priority they will switch when their slices run out, which will be 1096 * at most SCHED_SLICE_MAX. 1097 */ 1098 int 1099 sched_rr_interval(void) 1100 { 1101 return (SCHED_SLICE_MAX); 1102 } 1103 1104 static void 1105 sched_pctcpu_update(struct kse *ke) 1106 { 1107 /* 1108 * Adjust counters and watermark for pctcpu calc. 1109 */ 1110 if (ke->ke_ltick > ticks - SCHED_CPU_TICKS) { 1111 /* 1112 * Shift the tick count out so that the divide doesn't 1113 * round away our results. 1114 */ 1115 ke->ke_ticks <<= 10; 1116 ke->ke_ticks = (ke->ke_ticks / (ticks - ke->ke_ftick)) * 1117 SCHED_CPU_TICKS; 1118 ke->ke_ticks >>= 10; 1119 } else 1120 ke->ke_ticks = 0; 1121 ke->ke_ltick = ticks; 1122 ke->ke_ftick = ke->ke_ltick - SCHED_CPU_TICKS; 1123 } 1124 1125 void 1126 sched_prio(struct thread *td, u_char prio) 1127 { 1128 struct kse *ke; 1129 1130 ke = td->td_kse; 1131 mtx_assert(&sched_lock, MA_OWNED); 1132 if (TD_ON_RUNQ(td)) { 1133 /* 1134 * If the priority has been elevated due to priority 1135 * propagation, we may have to move ourselves to a new 1136 * queue. We still call adjustrunqueue below in case kse 1137 * needs to fix things up. 1138 */ 1139 if (prio < td->td_priority && ke && 1140 (ke->ke_flags & KEF_ASSIGNED) == 0 && 1141 ke->ke_runq != KSEQ_CPU(ke->ke_cpu)->ksq_curr) { 1142 runq_remove(ke->ke_runq, ke); 1143 ke->ke_runq = KSEQ_CPU(ke->ke_cpu)->ksq_curr; 1144 runq_add(ke->ke_runq, ke); 1145 } 1146 adjustrunqueue(td, prio); 1147 } else 1148 td->td_priority = prio; 1149 } 1150 1151 void 1152 sched_switch(struct thread *td, struct thread *newtd) 1153 { 1154 struct kse *ke; 1155 1156 mtx_assert(&sched_lock, MA_OWNED); 1157 1158 ke = td->td_kse; 1159 1160 td->td_last_kse = ke; 1161 td->td_lastcpu = td->td_oncpu; 1162 td->td_oncpu = NOCPU; 1163 td->td_flags &= ~TDF_NEEDRESCHED; 1164 td->td_pflags &= ~TDP_OWEPREEMPT; 1165 1166 /* 1167 * If the KSE has been assigned it may be in the process of switching 1168 * to the new cpu. This is the case in sched_bind(). 1169 */ 1170 if ((ke->ke_flags & KEF_ASSIGNED) == 0) { 1171 if (td == PCPU_GET(idlethread)) { 1172 TD_SET_CAN_RUN(td); 1173 } else if (TD_IS_RUNNING(td)) { 1174 kseq_load_rem(KSEQ_CPU(ke->ke_cpu), ke); 1175 setrunqueue(td); 1176 } else { 1177 if (ke->ke_runq) { 1178 kseq_load_rem(KSEQ_CPU(ke->ke_cpu), ke); 1179 } else if ((td->td_flags & TDF_IDLETD) == 0) 1180 kdb_backtrace(); 1181 /* 1182 * We will not be on the run queue. So we must be 1183 * sleeping or similar. 1184 */ 1185 if (td->td_proc->p_flag & P_SA) 1186 kse_reassign(ke); 1187 } 1188 } 1189 if (newtd != NULL) { 1190 kseq_load_add(KSEQ_SELF(), newtd->td_kse); 1191 ke->ke_cpu = PCPU_GET(cpuid); 1192 ke->ke_runq = KSEQ_SELF()->ksq_curr; 1193 } else 1194 newtd = choosethread(); 1195 if (td != newtd) 1196 cpu_switch(td, newtd); 1197 sched_lock.mtx_lock = (uintptr_t)td; 1198 1199 td->td_oncpu = PCPU_GET(cpuid); 1200 } 1201 1202 void 1203 sched_nice(struct proc *p, int nice) 1204 { 1205 struct ksegrp *kg; 1206 struct kse *ke; 1207 struct thread *td; 1208 struct kseq *kseq; 1209 1210 PROC_LOCK_ASSERT(p, MA_OWNED); 1211 mtx_assert(&sched_lock, MA_OWNED); 1212 /* 1213 * We need to adjust the nice counts for running KSEs. 1214 */ 1215 FOREACH_KSEGRP_IN_PROC(p, kg) { 1216 if (kg->kg_pri_class == PRI_TIMESHARE) { 1217 FOREACH_KSE_IN_GROUP(kg, ke) { 1218 if (ke->ke_runq == NULL) 1219 continue; 1220 kseq = KSEQ_CPU(ke->ke_cpu); 1221 kseq_nice_rem(kseq, p->p_nice); 1222 kseq_nice_add(kseq, nice); 1223 } 1224 } 1225 } 1226 p->p_nice = nice; 1227 FOREACH_KSEGRP_IN_PROC(p, kg) { 1228 sched_priority(kg); 1229 FOREACH_THREAD_IN_GROUP(kg, td) 1230 td->td_flags |= TDF_NEEDRESCHED; 1231 } 1232 } 1233 1234 void 1235 sched_sleep(struct thread *td) 1236 { 1237 mtx_assert(&sched_lock, MA_OWNED); 1238 1239 td->td_slptime = ticks; 1240 td->td_base_pri = td->td_priority; 1241 1242 CTR2(KTR_ULE, "sleep kse %p (tick: %d)", 1243 td->td_kse, td->td_slptime); 1244 } 1245 1246 void 1247 sched_wakeup(struct thread *td) 1248 { 1249 mtx_assert(&sched_lock, MA_OWNED); 1250 1251 /* 1252 * Let the kseg know how long we slept for. This is because process 1253 * interactivity behavior is modeled in the kseg. 1254 */ 1255 if (td->td_slptime) { 1256 struct ksegrp *kg; 1257 int hzticks; 1258 1259 kg = td->td_ksegrp; 1260 hzticks = (ticks - td->td_slptime) << 10; 1261 if (hzticks >= SCHED_SLP_RUN_MAX) { 1262 kg->kg_slptime = SCHED_SLP_RUN_MAX; 1263 kg->kg_runtime = 1; 1264 } else { 1265 kg->kg_slptime += hzticks; 1266 sched_interact_update(kg); 1267 } 1268 sched_priority(kg); 1269 if (td->td_kse) 1270 sched_slice(td->td_kse); 1271 CTR2(KTR_ULE, "wakeup kse %p (%d ticks)", 1272 td->td_kse, hzticks); 1273 td->td_slptime = 0; 1274 } 1275 setrunqueue(td); 1276 } 1277 1278 /* 1279 * Penalize the parent for creating a new child and initialize the child's 1280 * priority. 1281 */ 1282 void 1283 sched_fork(struct thread *td, struct proc *p1) 1284 { 1285 1286 mtx_assert(&sched_lock, MA_OWNED); 1287 1288 p1->p_nice = td->td_proc->p_nice; 1289 sched_fork_ksegrp(td, FIRST_KSEGRP_IN_PROC(p1)); 1290 sched_fork_kse(td, FIRST_KSE_IN_PROC(p1)); 1291 sched_fork_thread(td, FIRST_THREAD_IN_PROC(p1)); 1292 } 1293 1294 void 1295 sched_fork_kse(struct thread *td, struct kse *child) 1296 { 1297 1298 struct kse *ke = td->td_kse; 1299 1300 child->ke_slice = 1; /* Attempt to quickly learn interactivity. */ 1301 child->ke_cpu = ke->ke_cpu; 1302 child->ke_runq = NULL; 1303 1304 /* Grab our parents cpu estimation information. */ 1305 child->ke_ticks = ke->ke_ticks; 1306 child->ke_ltick = ke->ke_ltick; 1307 child->ke_ftick = ke->ke_ftick; 1308 } 1309 1310 void 1311 sched_fork_ksegrp(struct thread *td, struct ksegrp *child) 1312 { 1313 struct ksegrp *kg = td->td_ksegrp; 1314 PROC_LOCK_ASSERT(child->kg_proc, MA_OWNED); 1315 1316 child->kg_slptime = kg->kg_slptime; 1317 child->kg_runtime = kg->kg_runtime; 1318 child->kg_user_pri = kg->kg_user_pri; 1319 sched_interact_fork(child); 1320 kg->kg_runtime += tickincr << 10; 1321 sched_interact_update(kg); 1322 1323 CTR6(KTR_ULE, "sched_fork_ksegrp: %d(%d, %d) - %d(%d, %d)", 1324 kg->kg_proc->p_pid, kg->kg_slptime, kg->kg_runtime, 1325 child->kg_proc->p_pid, child->kg_slptime, child->kg_runtime); 1326 } 1327 1328 void 1329 sched_fork_thread(struct thread *td, struct thread *child) 1330 { 1331 } 1332 1333 void 1334 sched_class(struct ksegrp *kg, int class) 1335 { 1336 struct kseq *kseq; 1337 struct kse *ke; 1338 int nclass; 1339 int oclass; 1340 1341 mtx_assert(&sched_lock, MA_OWNED); 1342 if (kg->kg_pri_class == class) 1343 return; 1344 1345 nclass = PRI_BASE(class); 1346 oclass = PRI_BASE(kg->kg_pri_class); 1347 FOREACH_KSE_IN_GROUP(kg, ke) { 1348 if (ke->ke_state != KES_ONRUNQ && 1349 ke->ke_state != KES_THREAD) 1350 continue; 1351 kseq = KSEQ_CPU(ke->ke_cpu); 1352 1353 #ifdef SMP 1354 /* 1355 * On SMP if we're on the RUNQ we must adjust the transferable 1356 * count because could be changing to or from an interrupt 1357 * class. 1358 */ 1359 if (ke->ke_state == KES_ONRUNQ) { 1360 if (KSE_CAN_MIGRATE(ke, oclass)) { 1361 kseq->ksq_transferable--; 1362 kseq->ksq_group->ksg_transferable--; 1363 } 1364 if (KSE_CAN_MIGRATE(ke, nclass)) { 1365 kseq->ksq_transferable++; 1366 kseq->ksq_group->ksg_transferable++; 1367 } 1368 } 1369 #endif 1370 if (oclass == PRI_TIMESHARE) { 1371 kseq->ksq_load_timeshare--; 1372 kseq_nice_rem(kseq, kg->kg_proc->p_nice); 1373 } 1374 if (nclass == PRI_TIMESHARE) { 1375 kseq->ksq_load_timeshare++; 1376 kseq_nice_add(kseq, kg->kg_proc->p_nice); 1377 } 1378 } 1379 1380 kg->kg_pri_class = class; 1381 } 1382 1383 /* 1384 * Return some of the child's priority and interactivity to the parent. 1385 */ 1386 void 1387 sched_exit(struct proc *p, struct thread *td) 1388 { 1389 mtx_assert(&sched_lock, MA_OWNED); 1390 sched_exit_kse(FIRST_KSE_IN_PROC(p), td); 1391 sched_exit_ksegrp(FIRST_KSEGRP_IN_PROC(p), td); 1392 } 1393 1394 void 1395 sched_exit_kse(struct kse *ke, struct thread *td) 1396 { 1397 kseq_load_rem(KSEQ_CPU(td->td_kse->ke_cpu), td->td_kse); 1398 } 1399 1400 void 1401 sched_exit_ksegrp(struct ksegrp *kg, struct thread *td) 1402 { 1403 /* kg->kg_slptime += td->td_ksegrp->kg_slptime; */ 1404 kg->kg_runtime += td->td_ksegrp->kg_runtime; 1405 sched_interact_update(kg); 1406 } 1407 1408 void 1409 sched_exit_thread(struct thread *td, struct thread *child) 1410 { 1411 } 1412 1413 void 1414 sched_clock(struct thread *td) 1415 { 1416 struct kseq *kseq; 1417 struct ksegrp *kg; 1418 struct kse *ke; 1419 1420 mtx_assert(&sched_lock, MA_OWNED); 1421 kseq = KSEQ_SELF(); 1422 #ifdef SMP 1423 if (ticks == bal_tick) 1424 sched_balance(); 1425 if (ticks == gbal_tick) 1426 sched_balance_groups(); 1427 /* 1428 * We could have been assigned a non real-time thread without an 1429 * IPI. 1430 */ 1431 if (kseq->ksq_assigned) 1432 kseq_assign(kseq); /* Potentially sets NEEDRESCHED */ 1433 #endif 1434 /* 1435 * sched_setup() apparently happens prior to stathz being set. We 1436 * need to resolve the timers earlier in the boot so we can avoid 1437 * calculating this here. 1438 */ 1439 if (realstathz == 0) { 1440 realstathz = stathz ? stathz : hz; 1441 tickincr = hz / realstathz; 1442 /* 1443 * XXX This does not work for values of stathz that are much 1444 * larger than hz. 1445 */ 1446 if (tickincr == 0) 1447 tickincr = 1; 1448 } 1449 1450 ke = td->td_kse; 1451 kg = ke->ke_ksegrp; 1452 1453 /* Adjust ticks for pctcpu */ 1454 ke->ke_ticks++; 1455 ke->ke_ltick = ticks; 1456 1457 /* Go up to one second beyond our max and then trim back down */ 1458 if (ke->ke_ftick + SCHED_CPU_TICKS + hz < ke->ke_ltick) 1459 sched_pctcpu_update(ke); 1460 1461 if (td->td_flags & TDF_IDLETD) 1462 return; 1463 1464 CTR4(KTR_ULE, "Tick kse %p (slice: %d, slptime: %d, runtime: %d)", 1465 ke, ke->ke_slice, kg->kg_slptime >> 10, kg->kg_runtime >> 10); 1466 /* 1467 * We only do slicing code for TIMESHARE ksegrps. 1468 */ 1469 if (kg->kg_pri_class != PRI_TIMESHARE) 1470 return; 1471 /* 1472 * We used a tick charge it to the ksegrp so that we can compute our 1473 * interactivity. 1474 */ 1475 kg->kg_runtime += tickincr << 10; 1476 sched_interact_update(kg); 1477 1478 /* 1479 * We used up one time slice. 1480 */ 1481 if (--ke->ke_slice > 0) 1482 return; 1483 /* 1484 * We're out of time, recompute priorities and requeue. 1485 */ 1486 kseq_load_rem(kseq, ke); 1487 sched_priority(kg); 1488 sched_slice(ke); 1489 if (SCHED_CURR(kg, ke)) 1490 ke->ke_runq = kseq->ksq_curr; 1491 else 1492 ke->ke_runq = kseq->ksq_next; 1493 kseq_load_add(kseq, ke); 1494 td->td_flags |= TDF_NEEDRESCHED; 1495 } 1496 1497 int 1498 sched_runnable(void) 1499 { 1500 struct kseq *kseq; 1501 int load; 1502 1503 load = 1; 1504 1505 kseq = KSEQ_SELF(); 1506 #ifdef SMP 1507 if (kseq->ksq_assigned) { 1508 mtx_lock_spin(&sched_lock); 1509 kseq_assign(kseq); 1510 mtx_unlock_spin(&sched_lock); 1511 } 1512 #endif 1513 if ((curthread->td_flags & TDF_IDLETD) != 0) { 1514 if (kseq->ksq_load > 0) 1515 goto out; 1516 } else 1517 if (kseq->ksq_load - 1 > 0) 1518 goto out; 1519 load = 0; 1520 out: 1521 return (load); 1522 } 1523 1524 void 1525 sched_userret(struct thread *td) 1526 { 1527 struct ksegrp *kg; 1528 1529 kg = td->td_ksegrp; 1530 1531 if (td->td_priority != kg->kg_user_pri) { 1532 mtx_lock_spin(&sched_lock); 1533 td->td_priority = kg->kg_user_pri; 1534 mtx_unlock_spin(&sched_lock); 1535 } 1536 } 1537 1538 struct kse * 1539 sched_choose(void) 1540 { 1541 struct kseq *kseq; 1542 struct kse *ke; 1543 1544 mtx_assert(&sched_lock, MA_OWNED); 1545 kseq = KSEQ_SELF(); 1546 #ifdef SMP 1547 restart: 1548 if (kseq->ksq_assigned) 1549 kseq_assign(kseq); 1550 #endif 1551 ke = kseq_choose(kseq); 1552 if (ke) { 1553 #ifdef SMP 1554 if (ke->ke_ksegrp->kg_pri_class == PRI_IDLE) 1555 if (kseq_idled(kseq) == 0) 1556 goto restart; 1557 #endif 1558 kseq_runq_rem(kseq, ke); 1559 ke->ke_state = KES_THREAD; 1560 1561 if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) { 1562 CTR4(KTR_ULE, "Run kse %p from %p (slice: %d, pri: %d)", 1563 ke, ke->ke_runq, ke->ke_slice, 1564 ke->ke_thread->td_priority); 1565 } 1566 return (ke); 1567 } 1568 #ifdef SMP 1569 if (kseq_idled(kseq) == 0) 1570 goto restart; 1571 #endif 1572 return (NULL); 1573 } 1574 1575 void 1576 sched_add(struct thread *td) 1577 { 1578 1579 sched_add_internal(td, 1); 1580 } 1581 1582 static void 1583 sched_add_internal(struct thread *td, int preemptive) 1584 { 1585 struct kseq *kseq; 1586 struct ksegrp *kg; 1587 struct kse *ke; 1588 #ifdef SMP 1589 int canmigrate; 1590 #endif 1591 int class; 1592 1593 mtx_assert(&sched_lock, MA_OWNED); 1594 ke = td->td_kse; 1595 kg = td->td_ksegrp; 1596 if (ke->ke_flags & KEF_ASSIGNED) 1597 return; 1598 kseq = KSEQ_SELF(); 1599 KASSERT((ke->ke_thread != NULL), 1600 ("sched_add: No thread on KSE")); 1601 KASSERT((ke->ke_thread->td_kse != NULL), 1602 ("sched_add: No KSE on thread")); 1603 KASSERT(ke->ke_state != KES_ONRUNQ, 1604 ("sched_add: kse %p (%s) already in run queue", ke, 1605 ke->ke_proc->p_comm)); 1606 KASSERT(ke->ke_proc->p_sflag & PS_INMEM, 1607 ("sched_add: process swapped out")); 1608 KASSERT(ke->ke_runq == NULL, 1609 ("sched_add: KSE %p is still assigned to a run queue", ke)); 1610 1611 class = PRI_BASE(kg->kg_pri_class); 1612 switch (class) { 1613 case PRI_ITHD: 1614 case PRI_REALTIME: 1615 ke->ke_runq = kseq->ksq_curr; 1616 ke->ke_slice = SCHED_SLICE_MAX; 1617 ke->ke_cpu = PCPU_GET(cpuid); 1618 break; 1619 case PRI_TIMESHARE: 1620 if (SCHED_CURR(kg, ke)) 1621 ke->ke_runq = kseq->ksq_curr; 1622 else 1623 ke->ke_runq = kseq->ksq_next; 1624 break; 1625 case PRI_IDLE: 1626 /* 1627 * This is for priority prop. 1628 */ 1629 if (ke->ke_thread->td_priority < PRI_MIN_IDLE) 1630 ke->ke_runq = kseq->ksq_curr; 1631 else 1632 ke->ke_runq = &kseq->ksq_idle; 1633 ke->ke_slice = SCHED_SLICE_MIN; 1634 break; 1635 default: 1636 panic("Unknown pri class."); 1637 break; 1638 } 1639 #ifdef SMP 1640 /* 1641 * Don't migrate running threads here. Force the long term balancer 1642 * to do it. 1643 */ 1644 canmigrate = KSE_CAN_MIGRATE(ke, class); 1645 if (TD_IS_RUNNING(td)) 1646 canmigrate = 0; 1647 1648 /* 1649 * If this thread is pinned or bound, notify the target cpu. 1650 */ 1651 if (!canmigrate && ke->ke_cpu != PCPU_GET(cpuid) ) { 1652 ke->ke_runq = NULL; 1653 kseq_notify(ke, ke->ke_cpu); 1654 return; 1655 } 1656 /* 1657 * If we had been idle, clear our bit in the group and potentially 1658 * the global bitmap. If not, see if we should transfer this thread. 1659 */ 1660 if ((class == PRI_TIMESHARE || class == PRI_REALTIME) && 1661 (kseq->ksq_group->ksg_idlemask & PCPU_GET(cpumask)) != 0) { 1662 /* 1663 * Check to see if our group is unidling, and if so, remove it 1664 * from the global idle mask. 1665 */ 1666 if (kseq->ksq_group->ksg_idlemask == 1667 kseq->ksq_group->ksg_cpumask) 1668 atomic_clear_int(&kseq_idle, kseq->ksq_group->ksg_mask); 1669 /* 1670 * Now remove ourselves from the group specific idle mask. 1671 */ 1672 kseq->ksq_group->ksg_idlemask &= ~PCPU_GET(cpumask); 1673 } else if (kseq->ksq_load > 1 && canmigrate) 1674 if (kseq_transfer(kseq, ke, class)) 1675 return; 1676 ke->ke_cpu = PCPU_GET(cpuid); 1677 #endif 1678 /* 1679 * XXX With preemption this is not necessary. 1680 */ 1681 if (td->td_priority < curthread->td_priority) 1682 curthread->td_flags |= TDF_NEEDRESCHED; 1683 if (preemptive && maybe_preempt(td)) 1684 return; 1685 ke->ke_ksegrp->kg_runq_kses++; 1686 ke->ke_state = KES_ONRUNQ; 1687 1688 kseq_runq_add(kseq, ke); 1689 kseq_load_add(kseq, ke); 1690 } 1691 1692 void 1693 sched_rem(struct thread *td) 1694 { 1695 struct kseq *kseq; 1696 struct kse *ke; 1697 1698 ke = td->td_kse; 1699 /* 1700 * It is safe to just return here because sched_rem() is only ever 1701 * used in places where we're immediately going to add the 1702 * kse back on again. In that case it'll be added with the correct 1703 * thread and priority when the caller drops the sched_lock. 1704 */ 1705 if (ke->ke_flags & KEF_ASSIGNED) 1706 return; 1707 mtx_assert(&sched_lock, MA_OWNED); 1708 KASSERT((ke->ke_state == KES_ONRUNQ), 1709 ("sched_rem: KSE not on run queue")); 1710 1711 ke->ke_state = KES_THREAD; 1712 ke->ke_ksegrp->kg_runq_kses--; 1713 kseq = KSEQ_CPU(ke->ke_cpu); 1714 kseq_runq_rem(kseq, ke); 1715 kseq_load_rem(kseq, ke); 1716 } 1717 1718 fixpt_t 1719 sched_pctcpu(struct thread *td) 1720 { 1721 fixpt_t pctcpu; 1722 struct kse *ke; 1723 1724 pctcpu = 0; 1725 ke = td->td_kse; 1726 if (ke == NULL) 1727 return (0); 1728 1729 mtx_lock_spin(&sched_lock); 1730 if (ke->ke_ticks) { 1731 int rtick; 1732 1733 /* 1734 * Don't update more frequently than twice a second. Allowing 1735 * this causes the cpu usage to decay away too quickly due to 1736 * rounding errors. 1737 */ 1738 if (ke->ke_ftick + SCHED_CPU_TICKS < ke->ke_ltick || 1739 ke->ke_ltick < (ticks - (hz / 2))) 1740 sched_pctcpu_update(ke); 1741 /* How many rtick per second ? */ 1742 rtick = min(ke->ke_ticks / SCHED_CPU_TIME, SCHED_CPU_TICKS); 1743 pctcpu = (FSCALE * ((FSCALE * rtick)/realstathz)) >> FSHIFT; 1744 } 1745 1746 ke->ke_proc->p_swtime = ke->ke_ltick - ke->ke_ftick; 1747 mtx_unlock_spin(&sched_lock); 1748 1749 return (pctcpu); 1750 } 1751 1752 void 1753 sched_bind(struct thread *td, int cpu) 1754 { 1755 struct kse *ke; 1756 1757 mtx_assert(&sched_lock, MA_OWNED); 1758 ke = td->td_kse; 1759 ke->ke_flags |= KEF_BOUND; 1760 #ifdef SMP 1761 if (PCPU_GET(cpuid) == cpu) 1762 return; 1763 /* sched_rem without the runq_remove */ 1764 ke->ke_state = KES_THREAD; 1765 ke->ke_ksegrp->kg_runq_kses--; 1766 kseq_load_rem(KSEQ_CPU(ke->ke_cpu), ke); 1767 kseq_notify(ke, cpu); 1768 /* When we return from mi_switch we'll be on the correct cpu. */ 1769 mi_switch(SW_VOL, NULL); 1770 #endif 1771 } 1772 1773 void 1774 sched_unbind(struct thread *td) 1775 { 1776 mtx_assert(&sched_lock, MA_OWNED); 1777 td->td_kse->ke_flags &= ~KEF_BOUND; 1778 } 1779 1780 int 1781 sched_load(void) 1782 { 1783 #ifdef SMP 1784 int total; 1785 int i; 1786 1787 total = 0; 1788 for (i = 0; i <= ksg_maxid; i++) 1789 total += KSEQ_GROUP(i)->ksg_load; 1790 return (total); 1791 #else 1792 return (KSEQ_SELF()->ksq_sysload); 1793 #endif 1794 } 1795 1796 int 1797 sched_sizeof_kse(void) 1798 { 1799 return (sizeof(struct kse) + sizeof(struct ke_sched)); 1800 } 1801 1802 int 1803 sched_sizeof_ksegrp(void) 1804 { 1805 return (sizeof(struct ksegrp) + sizeof(struct kg_sched)); 1806 } 1807 1808 int 1809 sched_sizeof_proc(void) 1810 { 1811 return (sizeof(struct proc)); 1812 } 1813 1814 int 1815 sched_sizeof_thread(void) 1816 { 1817 return (sizeof(struct thread) + sizeof(struct td_sched)); 1818 } 1819