sched_ule.c revision 116377
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: head/sys/kern/sched_ule.c 116377 2003-06-15 04:14:25Z jeff $"); 29 30#include <sys/param.h> 31#include <sys/systm.h> 32#include <sys/kernel.h> 33#include <sys/ktr.h> 34#include <sys/lock.h> 35#include <sys/mutex.h> 36#include <sys/proc.h> 37#include <sys/resource.h> 38#include <sys/sched.h> 39#include <sys/smp.h> 40#include <sys/sx.h> 41#include <sys/sysctl.h> 42#include <sys/sysproto.h> 43#include <sys/vmmeter.h> 44#ifdef DDB 45#include <ddb/ddb.h> 46#endif 47#ifdef KTRACE 48#include <sys/uio.h> 49#include <sys/ktrace.h> 50#endif 51 52#include <machine/cpu.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 */ 58static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 59SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 60 61static void sched_setup(void *dummy); 62SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL) 63 64static SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "SCHED"); 65 66static int sched_strict; 67SYSCTL_INT(_kern_sched, OID_AUTO, strict, CTLFLAG_RD, &sched_strict, 0, ""); 68 69static int slice_min = 1; 70SYSCTL_INT(_kern_sched, OID_AUTO, slice_min, CTLFLAG_RW, &slice_min, 0, ""); 71 72static int slice_max = 10; 73SYSCTL_INT(_kern_sched, OID_AUTO, slice_max, CTLFLAG_RW, &slice_max, 0, ""); 74 75int realstathz; 76int tickincr = 1; 77 78#ifdef SMP 79/* Callout to handle load balancing SMP systems. */ 80static struct callout kseq_lb_callout; 81#endif 82 83/* 84 * These datastructures are allocated within their parent datastructure but 85 * are scheduler specific. 86 */ 87 88struct ke_sched { 89 int ske_slice; 90 struct runq *ske_runq; 91 /* The following variables are only used for pctcpu calculation */ 92 int ske_ltick; /* Last tick that we were running on */ 93 int ske_ftick; /* First tick that we were running on */ 94 int ske_ticks; /* Tick count */ 95 /* CPU that we have affinity for. */ 96 u_char ske_cpu; 97}; 98#define ke_slice ke_sched->ske_slice 99#define ke_runq ke_sched->ske_runq 100#define ke_ltick ke_sched->ske_ltick 101#define ke_ftick ke_sched->ske_ftick 102#define ke_ticks ke_sched->ske_ticks 103#define ke_cpu ke_sched->ske_cpu 104 105struct 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 112struct td_sched { 113 int std_slptime; 114}; 115#define td_slptime td_sched->std_slptime 116 117struct td_sched td_sched; 118struct ke_sched ke_sched; 119struct kg_sched kg_sched; 120 121struct ke_sched *kse0_sched = &ke_sched; 122struct kg_sched *ksegrp0_sched = &kg_sched; 123struct p_sched *proc0_sched = NULL; 124struct td_sched *thread0_sched = &td_sched; 125 126/* 127 * This priority range has 20 priorities on either end that are reachable 128 * only through nice values. 129 * 130 * PRI_RANGE: Total priority range for timeshare threads. 131 * PRI_NRESV: Reserved priorities for nice. 132 * PRI_BASE: The start of the dynamic range. 133 * DYN_RANGE: Number of priorities that are available int the dynamic 134 * priority range. 135 */ 136#define SCHED_PRI_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1) 137#define SCHED_PRI_NRESV PRIO_TOTAL 138#define SCHED_PRI_NHALF (PRIO_TOTAL / 2) 139#define SCHED_PRI_NTHRESH (SCHED_PRI_NHALF - 1) 140#define SCHED_PRI_BASE ((SCHED_PRI_NRESV / 2) + PRI_MIN_TIMESHARE) 141#define SCHED_DYN_RANGE (SCHED_PRI_RANGE - SCHED_PRI_NRESV) 142#define SCHED_PRI_INTERACT(score) \ 143 ((score) * SCHED_DYN_RANGE / SCHED_INTERACT_MAX) 144 145/* 146 * These determine the interactivity of a process. 147 * 148 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 149 * before throttling back. 150 * SLP_RUN_THROTTLE: Divisor for reducing slp/run time. 151 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 152 * INTERACT_THRESH: Threshhold for placement on the current runq. 153 */ 154#define SCHED_SLP_RUN_MAX ((hz / 4) << 10) 155#define SCHED_SLP_RUN_THROTTLE (2) 156#define SCHED_INTERACT_MAX (100) 157#define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 158#define SCHED_INTERACT_THRESH (20) 159 160/* 161 * These parameters and macros determine the size of the time slice that is 162 * granted to each thread. 163 * 164 * SLICE_MIN: Minimum time slice granted, in units of ticks. 165 * SLICE_MAX: Maximum time slice granted. 166 * SLICE_RANGE: Range of available time slices scaled by hz. 167 * SLICE_SCALE: The number slices granted per val in the range of [0, max]. 168 * SLICE_NICE: Determine the amount of slice granted to a scaled nice. 169 */ 170#define SCHED_SLICE_MIN (slice_min) 171#define SCHED_SLICE_MAX (slice_max) 172#define SCHED_SLICE_RANGE (SCHED_SLICE_MAX - SCHED_SLICE_MIN + 1) 173#define SCHED_SLICE_SCALE(val, max) (((val) * SCHED_SLICE_RANGE) / (max)) 174#define SCHED_SLICE_NICE(nice) \ 175 (SCHED_SLICE_MAX - SCHED_SLICE_SCALE((nice), SCHED_PRI_NTHRESH)) 176 177/* 178 * This macro determines whether or not the kse belongs on the current or 179 * next run queue. 180 * 181 * XXX nice value should effect how interactive a kg is. 182 */ 183#define SCHED_INTERACTIVE(kg) \ 184 (sched_interact_score(kg) < SCHED_INTERACT_THRESH) 185#define SCHED_CURR(kg, ke) \ 186 (ke->ke_thread->td_priority < PRI_MIN_TIMESHARE || 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 */ 201 202#define KSEQ_NCLASS (PRI_IDLE + 1) /* Number of run classes. */ 203 204struct kseq { 205 struct runq ksq_idle; /* Queue of IDLE threads. */ 206 struct runq ksq_timeshare[2]; /* Run queues for !IDLE. */ 207 struct runq *ksq_next; /* Next timeshare queue. */ 208 struct runq *ksq_curr; /* Current queue. */ 209 int ksq_loads[KSEQ_NCLASS]; /* Load for each class */ 210 int ksq_load; /* Aggregate load. */ 211 short ksq_nice[PRIO_TOTAL + 1]; /* KSEs in each nice bin. */ 212 short ksq_nicemin; /* Least nice. */ 213#ifdef SMP 214 unsigned int ksq_rslices; /* Slices on run queue */ 215#endif 216}; 217 218/* 219 * One kse queue per processor. 220 */ 221#ifdef SMP 222struct kseq kseq_cpu[MAXCPU]; 223#define KSEQ_SELF() (&kseq_cpu[PCPU_GET(cpuid)]) 224#define KSEQ_CPU(x) (&kseq_cpu[(x)]) 225#else 226struct kseq kseq_cpu; 227#define KSEQ_SELF() (&kseq_cpu) 228#define KSEQ_CPU(x) (&kseq_cpu) 229#endif 230 231static void sched_slice(struct kse *ke); 232static void sched_priority(struct ksegrp *kg); 233static int sched_interact_score(struct ksegrp *kg); 234void sched_pctcpu_update(struct kse *ke); 235int sched_pickcpu(void); 236 237/* Operations on per processor queues */ 238static struct kse * kseq_choose(struct kseq *kseq); 239static void kseq_setup(struct kseq *kseq); 240static void kseq_add(struct kseq *kseq, struct kse *ke); 241static void kseq_rem(struct kseq *kseq, struct kse *ke); 242static void kseq_nice_add(struct kseq *kseq, int nice); 243static void kseq_nice_rem(struct kseq *kseq, int nice); 244void kseq_print(int cpu); 245#ifdef SMP 246struct kseq * kseq_load_highest(void); 247void kseq_balance(void *arg); 248void kseq_move(struct kseq *from, int cpu); 249#endif 250 251void 252kseq_print(int cpu) 253{ 254 struct kseq *kseq; 255 int i; 256 257 kseq = KSEQ_CPU(cpu); 258 259 printf("kseq:\n"); 260 printf("\tload: %d\n", kseq->ksq_load); 261 printf("\tload ITHD: %d\n", kseq->ksq_loads[PRI_ITHD]); 262 printf("\tload REALTIME: %d\n", kseq->ksq_loads[PRI_REALTIME]); 263 printf("\tload TIMESHARE: %d\n", kseq->ksq_loads[PRI_TIMESHARE]); 264 printf("\tload IDLE: %d\n", kseq->ksq_loads[PRI_IDLE]); 265 printf("\tnicemin:\t%d\n", kseq->ksq_nicemin); 266 printf("\tnice counts:\n"); 267 for (i = 0; i < PRIO_TOTAL + 1; i++) 268 if (kseq->ksq_nice[i]) 269 printf("\t\t%d = %d\n", 270 i - SCHED_PRI_NHALF, kseq->ksq_nice[i]); 271} 272 273static void 274kseq_add(struct kseq *kseq, struct kse *ke) 275{ 276 mtx_assert(&sched_lock, MA_OWNED); 277 kseq->ksq_loads[PRI_BASE(ke->ke_ksegrp->kg_pri_class)]++; 278 kseq->ksq_load++; 279 if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) 280 CTR6(KTR_ULE, "Add kse %p to %p (slice: %d, pri: %d, nice: %d(%d))", 281 ke, ke->ke_runq, ke->ke_slice, ke->ke_thread->td_priority, 282 ke->ke_ksegrp->kg_nice, kseq->ksq_nicemin); 283 if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) 284 kseq_nice_add(kseq, ke->ke_ksegrp->kg_nice); 285#ifdef SMP 286 kseq->ksq_rslices += ke->ke_slice; 287#endif 288} 289 290static void 291kseq_rem(struct kseq *kseq, struct kse *ke) 292{ 293 mtx_assert(&sched_lock, MA_OWNED); 294 kseq->ksq_loads[PRI_BASE(ke->ke_ksegrp->kg_pri_class)]--; 295 kseq->ksq_load--; 296 ke->ke_runq = NULL; 297 if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) 298 kseq_nice_rem(kseq, ke->ke_ksegrp->kg_nice); 299#ifdef SMP 300 kseq->ksq_rslices -= ke->ke_slice; 301#endif 302} 303 304static void 305kseq_nice_add(struct kseq *kseq, int nice) 306{ 307 mtx_assert(&sched_lock, MA_OWNED); 308 /* Normalize to zero. */ 309 kseq->ksq_nice[nice + SCHED_PRI_NHALF]++; 310 if (nice < kseq->ksq_nicemin || kseq->ksq_loads[PRI_TIMESHARE] == 1) 311 kseq->ksq_nicemin = nice; 312} 313 314static void 315kseq_nice_rem(struct kseq *kseq, int nice) 316{ 317 int n; 318 319 mtx_assert(&sched_lock, MA_OWNED); 320 /* Normalize to zero. */ 321 n = nice + SCHED_PRI_NHALF; 322 kseq->ksq_nice[n]--; 323 KASSERT(kseq->ksq_nice[n] >= 0, ("Negative nice count.")); 324 325 /* 326 * If this wasn't the smallest nice value or there are more in 327 * this bucket we can just return. Otherwise we have to recalculate 328 * the smallest nice. 329 */ 330 if (nice != kseq->ksq_nicemin || 331 kseq->ksq_nice[n] != 0 || 332 kseq->ksq_loads[PRI_TIMESHARE] == 0) 333 return; 334 335 for (; n < SCHED_PRI_NRESV + 1; n++) 336 if (kseq->ksq_nice[n]) { 337 kseq->ksq_nicemin = n - SCHED_PRI_NHALF; 338 return; 339 } 340} 341 342#ifdef SMP 343/* 344 * kseq_balance is a simple CPU load balancing algorithm. It operates by 345 * finding the least loaded and most loaded cpu and equalizing their load 346 * by migrating some processes. 347 * 348 * Dealing only with two CPUs at a time has two advantages. Firstly, most 349 * installations will only have 2 cpus. Secondly, load balancing too much at 350 * once can have an unpleasant effect on the system. The scheduler rarely has 351 * enough information to make perfect decisions. So this algorithm chooses 352 * algorithm simplicity and more gradual effects on load in larger systems. 353 * 354 * It could be improved by considering the priorities and slices assigned to 355 * each task prior to balancing them. There are many pathological cases with 356 * any approach and so the semi random algorithm below may work as well as any. 357 * 358 */ 359void 360kseq_balance(void *arg) 361{ 362 struct kseq *kseq; 363 int high_load; 364 int low_load; 365 int high_cpu; 366 int low_cpu; 367 int move; 368 int diff; 369 int i; 370 371 high_cpu = 0; 372 low_cpu = 0; 373 high_load = 0; 374 low_load = -1; 375 376 mtx_lock_spin(&sched_lock); 377 for (i = 0; i < mp_maxid; i++) { 378 if (CPU_ABSENT(i)) 379 continue; 380 kseq = KSEQ_CPU(i); 381 if (kseq->ksq_load > high_load) { 382 high_load = kseq->ksq_load; 383 high_cpu = i; 384 } 385 if (low_load == -1 || kseq->ksq_load < low_load) { 386 low_load = kseq->ksq_load; 387 low_cpu = i; 388 } 389 } 390 391 /* 392 * Nothing to do. 393 */ 394 if (high_load < 2 || low_load == high_load) 395 goto out; 396 397 diff = high_load - low_load; 398 move = diff / 2; 399 if (diff & 0x1) 400 move++; 401 402 for (i = 0; i < move; i++) 403 kseq_move(KSEQ_CPU(high_cpu), low_cpu); 404 405out: 406 mtx_unlock_spin(&sched_lock); 407 callout_reset(&kseq_lb_callout, hz, kseq_balance, NULL); 408 409 return; 410} 411 412struct kseq * 413kseq_load_highest(void) 414{ 415 struct kseq *kseq; 416 int load; 417 int cpu; 418 int i; 419 420 mtx_assert(&sched_lock, MA_OWNED); 421 cpu = 0; 422 load = 0; 423 424 for (i = 0; i < mp_maxid; i++) { 425 if (CPU_ABSENT(i)) 426 continue; 427 kseq = KSEQ_CPU(i); 428 if (kseq->ksq_load > load) { 429 load = kseq->ksq_load; 430 cpu = i; 431 } 432 } 433 if (load > 1) 434 return (KSEQ_CPU(cpu)); 435 436 return (NULL); 437} 438 439void 440kseq_move(struct kseq *from, int cpu) 441{ 442 struct kse *ke; 443 444 ke = kseq_choose(from); 445 runq_remove(ke->ke_runq, ke); 446 ke->ke_state = KES_THREAD; 447 kseq_rem(from, ke); 448 449 ke->ke_cpu = cpu; 450 sched_add(ke); 451} 452#endif 453 454struct kse * 455kseq_choose(struct kseq *kseq) 456{ 457 struct kse *ke; 458 struct runq *swap; 459 460 mtx_assert(&sched_lock, MA_OWNED); 461 swap = NULL; 462 463 for (;;) { 464 ke = runq_choose(kseq->ksq_curr); 465 if (ke == NULL) { 466 /* 467 * We already swaped once and didn't get anywhere. 468 */ 469 if (swap) 470 break; 471 swap = kseq->ksq_curr; 472 kseq->ksq_curr = kseq->ksq_next; 473 kseq->ksq_next = swap; 474 continue; 475 } 476 /* 477 * If we encounter a slice of 0 the kse is in a 478 * TIMESHARE kse group and its nice was too far out 479 * of the range that receives slices. 480 */ 481 if (ke->ke_slice == 0) { 482 runq_remove(ke->ke_runq, ke); 483 sched_slice(ke); 484 ke->ke_runq = kseq->ksq_next; 485 runq_add(ke->ke_runq, ke); 486 continue; 487 } 488 return (ke); 489 } 490 491 return (runq_choose(&kseq->ksq_idle)); 492} 493 494static void 495kseq_setup(struct kseq *kseq) 496{ 497 runq_init(&kseq->ksq_timeshare[0]); 498 runq_init(&kseq->ksq_timeshare[1]); 499 runq_init(&kseq->ksq_idle); 500 501 kseq->ksq_curr = &kseq->ksq_timeshare[0]; 502 kseq->ksq_next = &kseq->ksq_timeshare[1]; 503 504 kseq->ksq_loads[PRI_ITHD] = 0; 505 kseq->ksq_loads[PRI_REALTIME] = 0; 506 kseq->ksq_loads[PRI_TIMESHARE] = 0; 507 kseq->ksq_loads[PRI_IDLE] = 0; 508 kseq->ksq_load = 0; 509#ifdef SMP 510 kseq->ksq_rslices = 0; 511#endif 512} 513 514static void 515sched_setup(void *dummy) 516{ 517 int i; 518 519 slice_min = (hz/100); 520 slice_max = (hz/10); 521 522 mtx_lock_spin(&sched_lock); 523 /* init kseqs */ 524 for (i = 0; i < MAXCPU; i++) 525 kseq_setup(KSEQ_CPU(i)); 526 527 kseq_add(KSEQ_SELF(), &kse0); 528 mtx_unlock_spin(&sched_lock); 529#ifdef SMP 530 callout_init(&kseq_lb_callout, 1); 531 kseq_balance(NULL); 532#endif 533} 534 535/* 536 * Scale the scheduling priority according to the "interactivity" of this 537 * process. 538 */ 539static void 540sched_priority(struct ksegrp *kg) 541{ 542 int pri; 543 544 if (kg->kg_pri_class != PRI_TIMESHARE) 545 return; 546 547 pri = SCHED_PRI_INTERACT(sched_interact_score(kg)); 548 pri += SCHED_PRI_BASE; 549 pri += kg->kg_nice; 550 551 if (pri > PRI_MAX_TIMESHARE) 552 pri = PRI_MAX_TIMESHARE; 553 else if (pri < PRI_MIN_TIMESHARE) 554 pri = PRI_MIN_TIMESHARE; 555 556 kg->kg_user_pri = pri; 557 558 return; 559} 560 561/* 562 * Calculate a time slice based on the properties of the kseg and the runq 563 * that we're on. This is only for PRI_TIMESHARE ksegrps. 564 */ 565static void 566sched_slice(struct kse *ke) 567{ 568 struct kseq *kseq; 569 struct ksegrp *kg; 570 571 kg = ke->ke_ksegrp; 572 kseq = KSEQ_CPU(ke->ke_cpu); 573 574 /* 575 * Rationale: 576 * KSEs in interactive ksegs get the minimum slice so that we 577 * quickly notice if it abuses its advantage. 578 * 579 * KSEs in non-interactive ksegs are assigned a slice that is 580 * based on the ksegs nice value relative to the least nice kseg 581 * on the run queue for this cpu. 582 * 583 * If the KSE is less nice than all others it gets the maximum 584 * slice and other KSEs will adjust their slice relative to 585 * this when they first expire. 586 * 587 * There is 20 point window that starts relative to the least 588 * nice kse on the run queue. Slice size is determined by 589 * the kse distance from the last nice ksegrp. 590 * 591 * If you are outside of the window you will get no slice and 592 * you will be reevaluated each time you are selected on the 593 * run queue. 594 * 595 */ 596 597 if (!SCHED_INTERACTIVE(kg)) { 598 int nice; 599 600 nice = kg->kg_nice + (0 - kseq->ksq_nicemin); 601 if (kseq->ksq_loads[PRI_TIMESHARE] == 0 || 602 kg->kg_nice < kseq->ksq_nicemin) 603 ke->ke_slice = SCHED_SLICE_MAX; 604 else if (nice <= SCHED_PRI_NTHRESH) 605 ke->ke_slice = SCHED_SLICE_NICE(nice); 606 else 607 ke->ke_slice = 0; 608 } else 609 ke->ke_slice = SCHED_SLICE_MIN; 610 611 CTR6(KTR_ULE, 612 "Sliced %p(%d) (nice: %d, nicemin: %d, load: %d, interactive: %d)", 613 ke, ke->ke_slice, kg->kg_nice, kseq->ksq_nicemin, 614 kseq->ksq_loads[PRI_TIMESHARE], SCHED_INTERACTIVE(kg)); 615 616 /* 617 * Check to see if we need to scale back the slp and run time 618 * in the kg. This will cause us to forget old interactivity 619 * while maintaining the current ratio. 620 */ 621 if ((kg->kg_runtime + kg->kg_slptime) > SCHED_SLP_RUN_MAX) { 622 kg->kg_runtime /= SCHED_SLP_RUN_THROTTLE; 623 kg->kg_slptime /= SCHED_SLP_RUN_THROTTLE; 624 } 625 CTR4(KTR_ULE, "Slp vs Run(2) %p (Slp %d, Run %d, Score %d)", 626 ke, kg->kg_slptime >> 10, kg->kg_runtime >> 10, 627 sched_interact_score(kg)); 628 629 return; 630} 631 632static int 633sched_interact_score(struct ksegrp *kg) 634{ 635 int div; 636 637 if (kg->kg_runtime > kg->kg_slptime) { 638 div = max(1, kg->kg_runtime / SCHED_INTERACT_HALF); 639 return (SCHED_INTERACT_HALF + 640 (SCHED_INTERACT_HALF - (kg->kg_slptime / div))); 641 } if (kg->kg_slptime > kg->kg_runtime) { 642 div = max(1, kg->kg_slptime / SCHED_INTERACT_HALF); 643 return (kg->kg_runtime / div); 644 } 645 646 /* 647 * This can happen if slptime and runtime are 0. 648 */ 649 return (0); 650 651} 652 653/* 654 * This is only somewhat accurate since given many processes of the same 655 * priority they will switch when their slices run out, which will be 656 * at most SCHED_SLICE_MAX. 657 */ 658int 659sched_rr_interval(void) 660{ 661 return (SCHED_SLICE_MAX); 662} 663 664void 665sched_pctcpu_update(struct kse *ke) 666{ 667 /* 668 * Adjust counters and watermark for pctcpu calc. 669 */ 670 671 /* 672 * Shift the tick count out so that the divide doesn't round away 673 * our results. 674 */ 675 ke->ke_ticks <<= 10; 676 ke->ke_ticks = (ke->ke_ticks / (ke->ke_ltick - ke->ke_ftick)) * 677 SCHED_CPU_TICKS; 678 ke->ke_ticks >>= 10; 679 ke->ke_ltick = ticks; 680 ke->ke_ftick = ke->ke_ltick - SCHED_CPU_TICKS; 681} 682 683#ifdef SMP 684/* XXX Should be changed to kseq_load_lowest() */ 685int 686sched_pickcpu(void) 687{ 688 struct kseq *kseq; 689 int load; 690 int cpu; 691 int i; 692 693 mtx_assert(&sched_lock, MA_OWNED); 694 if (!smp_started) 695 return (0); 696 697 load = 0; 698 cpu = 0; 699 700 for (i = 0; i < mp_maxid; i++) { 701 if (CPU_ABSENT(i)) 702 continue; 703 kseq = KSEQ_CPU(i); 704 if (kseq->ksq_load < load) { 705 cpu = i; 706 load = kseq->ksq_load; 707 } 708 } 709 710 CTR1(KTR_RUNQ, "sched_pickcpu: %d", cpu); 711 return (cpu); 712} 713#else 714int 715sched_pickcpu(void) 716{ 717 return (0); 718} 719#endif 720 721void 722sched_prio(struct thread *td, u_char prio) 723{ 724 struct kse *ke; 725 struct runq *rq; 726 727 mtx_assert(&sched_lock, MA_OWNED); 728 ke = td->td_kse; 729 td->td_priority = prio; 730 731 if (TD_ON_RUNQ(td)) { 732 rq = ke->ke_runq; 733 734 runq_remove(rq, ke); 735 runq_add(rq, ke); 736 } 737} 738 739void 740sched_switchout(struct thread *td) 741{ 742 struct kse *ke; 743 744 mtx_assert(&sched_lock, MA_OWNED); 745 746 ke = td->td_kse; 747 748 td->td_last_kse = ke; 749 td->td_lastcpu = td->td_oncpu; 750 td->td_oncpu = NOCPU; 751 td->td_flags &= ~TDF_NEEDRESCHED; 752 753 if (TD_IS_RUNNING(td)) { 754 /* 755 * This queue is always correct except for idle threads which 756 * have a higher priority due to priority propagation. 757 */ 758 if (ke->ke_ksegrp->kg_pri_class == PRI_IDLE && 759 ke->ke_thread->td_priority > PRI_MIN_IDLE) 760 ke->ke_runq = KSEQ_SELF()->ksq_curr; 761 runq_add(ke->ke_runq, ke); 762 /* setrunqueue(td); */ 763 return; 764 } 765 if (ke->ke_runq) 766 kseq_rem(KSEQ_CPU(ke->ke_cpu), ke); 767 /* 768 * We will not be on the run queue. So we must be 769 * sleeping or similar. 770 */ 771 if (td->td_proc->p_flag & P_SA) 772 kse_reassign(ke); 773} 774 775void 776sched_switchin(struct thread *td) 777{ 778 /* struct kse *ke = td->td_kse; */ 779 mtx_assert(&sched_lock, MA_OWNED); 780 781 td->td_oncpu = PCPU_GET(cpuid); 782} 783 784void 785sched_nice(struct ksegrp *kg, int nice) 786{ 787 struct kse *ke; 788 struct thread *td; 789 struct kseq *kseq; 790 791 PROC_LOCK_ASSERT(kg->kg_proc, MA_OWNED); 792 mtx_assert(&sched_lock, MA_OWNED); 793 /* 794 * We need to adjust the nice counts for running KSEs. 795 */ 796 if (kg->kg_pri_class == PRI_TIMESHARE) 797 FOREACH_KSE_IN_GROUP(kg, ke) { 798 if (ke->ke_state != KES_ONRUNQ && 799 ke->ke_state != KES_THREAD) 800 continue; 801 kseq = KSEQ_CPU(ke->ke_cpu); 802 kseq_nice_rem(kseq, kg->kg_nice); 803 kseq_nice_add(kseq, nice); 804 } 805 kg->kg_nice = nice; 806 sched_priority(kg); 807 FOREACH_THREAD_IN_GROUP(kg, td) 808 td->td_flags |= TDF_NEEDRESCHED; 809} 810 811void 812sched_sleep(struct thread *td, u_char prio) 813{ 814 mtx_assert(&sched_lock, MA_OWNED); 815 816 td->td_slptime = ticks; 817 td->td_priority = prio; 818 819 CTR2(KTR_ULE, "sleep kse %p (tick: %d)", 820 td->td_kse, td->td_slptime); 821} 822 823void 824sched_wakeup(struct thread *td) 825{ 826 mtx_assert(&sched_lock, MA_OWNED); 827 828 /* 829 * Let the kseg know how long we slept for. This is because process 830 * interactivity behavior is modeled in the kseg. 831 */ 832 if (td->td_slptime) { 833 struct ksegrp *kg; 834 int hzticks; 835 836 kg = td->td_ksegrp; 837 hzticks = ticks - td->td_slptime; 838 kg->kg_slptime += hzticks << 10; 839 sched_priority(kg); 840 CTR2(KTR_ULE, "wakeup kse %p (%d ticks)", 841 td->td_kse, hzticks); 842 td->td_slptime = 0; 843 } 844 setrunqueue(td); 845 if (td->td_priority < curthread->td_priority) 846 curthread->td_flags |= TDF_NEEDRESCHED; 847} 848 849/* 850 * Penalize the parent for creating a new child and initialize the child's 851 * priority. 852 */ 853void 854sched_fork(struct proc *p, struct proc *p1) 855{ 856 857 mtx_assert(&sched_lock, MA_OWNED); 858 859 sched_fork_ksegrp(FIRST_KSEGRP_IN_PROC(p), FIRST_KSEGRP_IN_PROC(p1)); 860 sched_fork_kse(FIRST_KSE_IN_PROC(p), FIRST_KSE_IN_PROC(p1)); 861 sched_fork_thread(FIRST_THREAD_IN_PROC(p), FIRST_THREAD_IN_PROC(p1)); 862} 863 864void 865sched_fork_kse(struct kse *ke, struct kse *child) 866{ 867 868 child->ke_slice = 1; /* Attempt to quickly learn interactivity. */ 869 child->ke_cpu = ke->ke_cpu; /* sched_pickcpu(); */ 870 child->ke_runq = NULL; 871 872 /* 873 * Claim that we've been running for one second for statistical 874 * purposes. 875 */ 876 child->ke_ticks = 0; 877 child->ke_ltick = ticks; 878 child->ke_ftick = ticks - hz; 879} 880 881void 882sched_fork_ksegrp(struct ksegrp *kg, struct ksegrp *child) 883{ 884 885 PROC_LOCK_ASSERT(child->kg_proc, MA_OWNED); 886 /* XXX Need something better here */ 887 888#if 1 889 child->kg_slptime = kg->kg_slptime; 890 child->kg_runtime = kg->kg_runtime; 891#else 892 if (kg->kg_slptime > kg->kg_runtime) { 893 child->kg_slptime = SCHED_DYN_RANGE; 894 child->kg_runtime = kg->kg_slptime / SCHED_DYN_RANGE; 895 } else { 896 child->kg_runtime = SCHED_DYN_RANGE; 897 child->kg_slptime = kg->kg_runtime / SCHED_DYN_RANGE; 898 } 899#endif 900 901 child->kg_user_pri = kg->kg_user_pri; 902 child->kg_nice = kg->kg_nice; 903} 904 905void 906sched_fork_thread(struct thread *td, struct thread *child) 907{ 908} 909 910void 911sched_class(struct ksegrp *kg, int class) 912{ 913 struct kseq *kseq; 914 struct kse *ke; 915 916 mtx_assert(&sched_lock, MA_OWNED); 917 if (kg->kg_pri_class == class) 918 return; 919 920 FOREACH_KSE_IN_GROUP(kg, ke) { 921 if (ke->ke_state != KES_ONRUNQ && 922 ke->ke_state != KES_THREAD) 923 continue; 924 kseq = KSEQ_CPU(ke->ke_cpu); 925 926 kseq->ksq_loads[PRI_BASE(kg->kg_pri_class)]--; 927 kseq->ksq_loads[PRI_BASE(class)]++; 928 929 if (kg->kg_pri_class == PRI_TIMESHARE) 930 kseq_nice_rem(kseq, kg->kg_nice); 931 else if (class == PRI_TIMESHARE) 932 kseq_nice_add(kseq, kg->kg_nice); 933 } 934 935 kg->kg_pri_class = class; 936} 937 938/* 939 * Return some of the child's priority and interactivity to the parent. 940 */ 941void 942sched_exit(struct proc *p, struct proc *child) 943{ 944 /* XXX Need something better here */ 945 mtx_assert(&sched_lock, MA_OWNED); 946 sched_exit_kse(FIRST_KSE_IN_PROC(p), FIRST_KSE_IN_PROC(child)); 947 sched_exit_ksegrp(FIRST_KSEGRP_IN_PROC(p), FIRST_KSEGRP_IN_PROC(child)); 948} 949 950void 951sched_exit_kse(struct kse *ke, struct kse *child) 952{ 953 kseq_rem(KSEQ_CPU(child->ke_cpu), child); 954} 955 956void 957sched_exit_ksegrp(struct ksegrp *kg, struct ksegrp *child) 958{ 959 kg->kg_slptime += child->kg_slptime; 960 kg->kg_runtime += child->kg_runtime; 961 if ((kg->kg_runtime + kg->kg_slptime) > SCHED_SLP_RUN_MAX) { 962 kg->kg_runtime /= SCHED_SLP_RUN_THROTTLE; 963 kg->kg_slptime /= SCHED_SLP_RUN_THROTTLE; 964 } 965} 966 967void 968sched_exit_thread(struct thread *td, struct thread *child) 969{ 970} 971 972void 973sched_clock(struct kse *ke) 974{ 975 struct kseq *kseq; 976 struct ksegrp *kg; 977 struct thread *td; 978#if 0 979 struct kse *nke; 980#endif 981 982 /* 983 * sched_setup() apparently happens prior to stathz being set. We 984 * need to resolve the timers earlier in the boot so we can avoid 985 * calculating this here. 986 */ 987 if (realstathz == 0) { 988 realstathz = stathz ? stathz : hz; 989 tickincr = hz / realstathz; 990 /* 991 * XXX This does not work for values of stathz that are much 992 * larger than hz. 993 */ 994 if (tickincr == 0) 995 tickincr = 1; 996 } 997 998 td = ke->ke_thread; 999 kg = ke->ke_ksegrp; 1000 1001 mtx_assert(&sched_lock, MA_OWNED); 1002 KASSERT((td != NULL), ("schedclock: null thread pointer")); 1003 1004 /* Adjust ticks for pctcpu */ 1005 ke->ke_ticks++; 1006 ke->ke_ltick = ticks; 1007 1008 /* Go up to one second beyond our max and then trim back down */ 1009 if (ke->ke_ftick + SCHED_CPU_TICKS + hz < ke->ke_ltick) 1010 sched_pctcpu_update(ke); 1011 1012 if (td->td_flags & TDF_IDLETD) 1013 return; 1014 1015 CTR4(KTR_ULE, "Tick kse %p (slice: %d, slptime: %d, runtime: %d)", 1016 ke, ke->ke_slice, kg->kg_slptime >> 10, kg->kg_runtime >> 10); 1017 1018 /* 1019 * We only do slicing code for TIMESHARE ksegrps. 1020 */ 1021 if (kg->kg_pri_class != PRI_TIMESHARE) 1022 return; 1023 /* 1024 * Check for a higher priority task on the run queue. This can happen 1025 * on SMP if another processor woke up a process on our runq. 1026 */ 1027 kseq = KSEQ_SELF(); 1028#if 0 1029 if (kseq->ksq_load > 1 && (nke = kseq_choose(kseq)) != NULL) { 1030 if (sched_strict && 1031 nke->ke_thread->td_priority < td->td_priority) 1032 td->td_flags |= TDF_NEEDRESCHED; 1033 else if (nke->ke_thread->td_priority < 1034 td->td_priority SCHED_PRIO_SLOP) 1035 1036 if (nke->ke_thread->td_priority < td->td_priority) 1037 td->td_flags |= TDF_NEEDRESCHED; 1038 } 1039#endif 1040 /* 1041 * We used a tick charge it to the ksegrp so that we can compute our 1042 * interactivity. 1043 */ 1044 kg->kg_runtime += tickincr << 10; 1045 1046 /* 1047 * We used up one time slice. 1048 */ 1049 ke->ke_slice--; 1050#ifdef SMP 1051 kseq->ksq_rslices--; 1052#endif 1053 1054 if (ke->ke_slice > 0) 1055 return; 1056 /* 1057 * We're out of time, recompute priorities and requeue. 1058 */ 1059 kseq_rem(kseq, ke); 1060 sched_priority(kg); 1061 sched_slice(ke); 1062 if (SCHED_CURR(kg, ke)) 1063 ke->ke_runq = kseq->ksq_curr; 1064 else 1065 ke->ke_runq = kseq->ksq_next; 1066 kseq_add(kseq, ke); 1067 td->td_flags |= TDF_NEEDRESCHED; 1068} 1069 1070int 1071sched_runnable(void) 1072{ 1073 struct kseq *kseq; 1074 int load; 1075 1076 load = 1; 1077 1078 mtx_lock_spin(&sched_lock); 1079 kseq = KSEQ_SELF(); 1080 1081 if (kseq->ksq_load) 1082 goto out; 1083#ifdef SMP 1084 /* 1085 * For SMP we may steal other processor's KSEs. Just search until we 1086 * verify that at least on other cpu has a runnable task. 1087 */ 1088 if (smp_started) { 1089 int i; 1090 1091 for (i = 0; i < mp_maxid; i++) { 1092 if (CPU_ABSENT(i)) 1093 continue; 1094 kseq = KSEQ_CPU(i); 1095 if (kseq->ksq_load > 1) 1096 goto out; 1097 } 1098 } 1099#endif 1100 load = 0; 1101out: 1102 mtx_unlock_spin(&sched_lock); 1103 return (load); 1104} 1105 1106void 1107sched_userret(struct thread *td) 1108{ 1109 struct ksegrp *kg; 1110 struct kseq *kseq; 1111 struct kse *ke; 1112 1113 kg = td->td_ksegrp; 1114 1115 if (td->td_priority != kg->kg_user_pri) { 1116 mtx_lock_spin(&sched_lock); 1117 td->td_priority = kg->kg_user_pri; 1118 kseq = KSEQ_SELF(); 1119 if (td->td_ksegrp->kg_pri_class == PRI_TIMESHARE && 1120 kseq->ksq_load > 1 && 1121 (ke = kseq_choose(kseq)) != NULL && 1122 ke->ke_thread->td_priority < td->td_priority) 1123 curthread->td_flags |= TDF_NEEDRESCHED; 1124 mtx_unlock_spin(&sched_lock); 1125 } 1126} 1127 1128struct kse * 1129sched_choose(void) 1130{ 1131 struct kseq *kseq; 1132 struct kse *ke; 1133 1134 mtx_assert(&sched_lock, MA_OWNED); 1135#ifdef SMP 1136retry: 1137#endif 1138 kseq = KSEQ_SELF(); 1139 ke = kseq_choose(kseq); 1140 if (ke) { 1141 runq_remove(ke->ke_runq, ke); 1142 ke->ke_state = KES_THREAD; 1143 1144 if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) { 1145 CTR4(KTR_ULE, "Run kse %p from %p (slice: %d, pri: %d)", 1146 ke, ke->ke_runq, ke->ke_slice, 1147 ke->ke_thread->td_priority); 1148 } 1149 return (ke); 1150 } 1151 1152#ifdef SMP 1153 if (smp_started) { 1154 /* 1155 * Find the cpu with the highest load and steal one proc. 1156 */ 1157 if ((kseq = kseq_load_highest()) == NULL) 1158 return (NULL); 1159 1160 /* 1161 * Remove this kse from this kseq and runq and then requeue 1162 * on the current processor. Then we will dequeue it 1163 * normally above. 1164 */ 1165 kseq_move(kseq, PCPU_GET(cpuid)); 1166 goto retry; 1167 } 1168#endif 1169 1170 return (NULL); 1171} 1172 1173void 1174sched_add(struct kse *ke) 1175{ 1176 struct kseq *kseq; 1177 struct ksegrp *kg; 1178 1179 mtx_assert(&sched_lock, MA_OWNED); 1180 KASSERT((ke->ke_thread != NULL), ("sched_add: No thread on KSE")); 1181 KASSERT((ke->ke_thread->td_kse != NULL), 1182 ("sched_add: No KSE on thread")); 1183 KASSERT(ke->ke_state != KES_ONRUNQ, 1184 ("sched_add: kse %p (%s) already in run queue", ke, 1185 ke->ke_proc->p_comm)); 1186 KASSERT(ke->ke_proc->p_sflag & PS_INMEM, 1187 ("sched_add: process swapped out")); 1188 KASSERT(ke->ke_runq == NULL, 1189 ("sched_add: KSE %p is still assigned to a run queue", ke)); 1190 1191 kg = ke->ke_ksegrp; 1192 1193 switch (PRI_BASE(kg->kg_pri_class)) { 1194 case PRI_ITHD: 1195 case PRI_REALTIME: 1196 kseq = KSEQ_SELF(); 1197 ke->ke_runq = kseq->ksq_curr; 1198 ke->ke_slice = SCHED_SLICE_MAX; 1199 ke->ke_cpu = PCPU_GET(cpuid); 1200 break; 1201 case PRI_TIMESHARE: 1202 kseq = KSEQ_CPU(ke->ke_cpu); 1203 if (SCHED_CURR(kg, ke)) 1204 ke->ke_runq = kseq->ksq_curr; 1205 else 1206 ke->ke_runq = kseq->ksq_next; 1207 break; 1208 case PRI_IDLE: 1209 kseq = KSEQ_CPU(ke->ke_cpu); 1210 /* 1211 * This is for priority prop. 1212 */ 1213 if (ke->ke_thread->td_priority > PRI_MIN_IDLE) 1214 ke->ke_runq = kseq->ksq_curr; 1215 else 1216 ke->ke_runq = &kseq->ksq_idle; 1217 ke->ke_slice = SCHED_SLICE_MIN; 1218 break; 1219 default: 1220 panic("Unknown pri class.\n"); 1221 break; 1222 } 1223 1224 ke->ke_ksegrp->kg_runq_kses++; 1225 ke->ke_state = KES_ONRUNQ; 1226 1227 runq_add(ke->ke_runq, ke); 1228 kseq_add(kseq, ke); 1229} 1230 1231void 1232sched_rem(struct kse *ke) 1233{ 1234 struct kseq *kseq; 1235 1236 mtx_assert(&sched_lock, MA_OWNED); 1237 KASSERT((ke->ke_state == KES_ONRUNQ), ("KSE not on run queue")); 1238 1239 ke->ke_state = KES_THREAD; 1240 ke->ke_ksegrp->kg_runq_kses--; 1241 kseq = KSEQ_CPU(ke->ke_cpu); 1242 runq_remove(ke->ke_runq, ke); 1243 kseq_rem(kseq, ke); 1244} 1245 1246fixpt_t 1247sched_pctcpu(struct kse *ke) 1248{ 1249 fixpt_t pctcpu; 1250 1251 pctcpu = 0; 1252 1253 mtx_lock_spin(&sched_lock); 1254 if (ke->ke_ticks) { 1255 int rtick; 1256 1257 /* Update to account for time potentially spent sleeping */ 1258 ke->ke_ltick = ticks; 1259 /* 1260 * Don't update more frequently than twice a second. Allowing 1261 * this causes the cpu usage to decay away too quickly due to 1262 * rounding errors. 1263 */ 1264 if (ke->ke_ltick < (ticks - (hz / 2))) 1265 sched_pctcpu_update(ke); 1266 1267 /* How many rtick per second ? */ 1268 rtick = min(ke->ke_ticks / SCHED_CPU_TIME, SCHED_CPU_TICKS); 1269 pctcpu = (FSCALE * ((FSCALE * rtick)/realstathz)) >> FSHIFT; 1270 } 1271 1272 ke->ke_proc->p_swtime = ke->ke_ltick - ke->ke_ftick; 1273 mtx_unlock_spin(&sched_lock); 1274 1275 return (pctcpu); 1276} 1277 1278int 1279sched_sizeof_kse(void) 1280{ 1281 return (sizeof(struct kse) + sizeof(struct ke_sched)); 1282} 1283 1284int 1285sched_sizeof_ksegrp(void) 1286{ 1287 return (sizeof(struct ksegrp) + sizeof(struct kg_sched)); 1288} 1289 1290int 1291sched_sizeof_proc(void) 1292{ 1293 return (sizeof(struct proc)); 1294} 1295 1296int 1297sched_sizeof_thread(void) 1298{ 1299 return (sizeof(struct thread) + sizeof(struct td_sched)); 1300} 1301