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/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 */ 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, "SCHED"); 65 66 static int sched_strict; 67 SYSCTL_INT(_kern_sched, OID_AUTO, strict, CTLFLAG_RD, &sched_strict, 0, ""); 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 #ifdef SMP 79 /* Callout to handle load balancing SMP systems. */ 80 static 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 88 struct 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 104 105 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_TOTAL 138 #define SCHED_PRI_NHALF (PRIO_TOTAL / 2) 139 #define SCHED_PRI_NTHRESH (SCHED_PRI_NHALF - 1) 140 #define SCHED_PRI_BASE (PRI_MIN_TIMESHARE) 141 #define SCHED_PRI_INTERACT(score) \ 142 ((score) * SCHED_PRI_RANGE / SCHED_INTERACT_MAX) 143 144 /* 145 * These determine the interactivity of a process. 146 * 147 * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate 148 * before throttling back. 149 * SLP_RUN_THROTTLE: Divisor for reducing slp/run time. 150 * INTERACT_MAX: Maximum interactivity value. Smaller is better. 151 * INTERACT_THRESH: Threshhold for placement on the current runq. 152 */ 153 #define SCHED_SLP_RUN_MAX ((hz * 2) << 10) 154 #define SCHED_SLP_RUN_THROTTLE (2) 155 #define SCHED_INTERACT_MAX (100) 156 #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) 157 #define SCHED_INTERACT_THRESH (20) 158 159 /* 160 * These parameters and macros determine the size of the time slice that is 161 * granted to each thread. 162 * 163 * SLICE_MIN: Minimum time slice granted, in units of ticks. 164 * SLICE_MAX: Maximum time slice granted. 165 * SLICE_RANGE: Range of available time slices scaled by hz. 166 * SLICE_SCALE: The number slices granted per val in the range of [0, max]. 167 * SLICE_NICE: Determine the amount of slice granted to a scaled nice. 168 */ 169 #define SCHED_SLICE_MIN (slice_min) 170 #define SCHED_SLICE_MAX (slice_max) 171 #define SCHED_SLICE_RANGE (SCHED_SLICE_MAX - SCHED_SLICE_MIN + 1) 172 #define SCHED_SLICE_SCALE(val, max) (((val) * SCHED_SLICE_RANGE) / (max)) 173 #define SCHED_SLICE_NICE(nice) \ 174 (SCHED_SLICE_MAX - SCHED_SLICE_SCALE((nice), SCHED_PRI_NTHRESH)) 175 176 /* 177 * This macro determines whether or not the kse belongs on the current or 178 * next run queue. 179 * 180 * XXX nice value should effect how interactive a kg is. 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 < PRI_MIN_TIMESHARE || SCHED_INTERACTIVE(kg)) 186 187 /* 188 * Cpu percentage computation macros and defines. 189 * 190 * SCHED_CPU_TIME: Number of seconds to average the cpu usage across. 191 * SCHED_CPU_TICKS: Number of hz ticks to average the cpu usage across. 192 */ 193 194 #define SCHED_CPU_TIME 10 195 #define SCHED_CPU_TICKS (hz * SCHED_CPU_TIME) 196 197 /* 198 * kseq - per processor runqs and statistics. 199 */ 200 201 #define KSEQ_NCLASS (PRI_IDLE + 1) /* Number of run classes. */ 202 203 struct kseq { 204 struct runq ksq_idle; /* Queue of IDLE threads. */ 205 struct runq ksq_timeshare[2]; /* Run queues for !IDLE. */ 206 struct runq *ksq_next; /* Next timeshare queue. */ 207 struct runq *ksq_curr; /* Current queue. */ 208 int ksq_loads[KSEQ_NCLASS]; /* Load for each class */ 209 int ksq_load; /* Aggregate load. */ 210 short ksq_nice[PRIO_TOTAL + 1]; /* KSEs in each nice bin. */ 211 short ksq_nicemin; /* Least nice. */ 212 #ifdef SMP 213 unsigned int ksq_rslices; /* Slices on run queue */ 214 #endif 215 }; 216 217 /* 218 * One kse queue per processor. 219 */ 220 #ifdef SMP 221 struct kseq kseq_cpu[MAXCPU]; 222 #define KSEQ_SELF() (&kseq_cpu[PCPU_GET(cpuid)]) 223 #define KSEQ_CPU(x) (&kseq_cpu[(x)]) 224 #else 225 struct kseq kseq_cpu; 226 #define KSEQ_SELF() (&kseq_cpu) 227 #define KSEQ_CPU(x) (&kseq_cpu) 228 #endif 229 230 static void sched_slice(struct kse *ke); 231 static void sched_priority(struct ksegrp *kg); 232 static int sched_interact_score(struct ksegrp *kg); 233 static void sched_interact_update(struct ksegrp *kg); 234 void sched_pctcpu_update(struct kse *ke); 235 int sched_pickcpu(void); 236 237 /* Operations on per processor queues */ 238 static struct kse * kseq_choose(struct kseq *kseq); 239 static void kseq_setup(struct kseq *kseq); 240 static void kseq_add(struct kseq *kseq, struct kse *ke); 241 static void kseq_rem(struct kseq *kseq, struct kse *ke); 242 static void kseq_nice_add(struct kseq *kseq, int nice); 243 static void kseq_nice_rem(struct kseq *kseq, int nice); 244 void kseq_print(int cpu); 245 #ifdef SMP 246 struct kseq * kseq_load_highest(void); 247 void kseq_balance(void *arg); 248 void kseq_move(struct kseq *from, int cpu); 249 #endif 250 251 void 252 kseq_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 } 272 273 static void 274 kseq_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 } 289 290 static void 291 kseq_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 } 303 304 static void 305 kseq_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 } 313 314 static void 315 kseq_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 */ 359 void 360 kseq_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); 404 405 out: 406 mtx_unlock_spin(&sched_lock); 407 callout_reset(&kseq_lb_callout, hz, kseq_balance, NULL); 408 409 return; 410 } 411 412 struct kseq * 413 kseq_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 } 438 439 void 440 kseq_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 453 454 struct kse * 455 kseq_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 } 493 494 static void 495 kseq_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 } 513 514 static void 515 sched_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 */ 539 static void 540 sched_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 */ 565 static void 566 sched_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 sched_interact_update(kg); 622 623 return; 624 } 625 626 static void 627 sched_interact_update(struct ksegrp *kg) 628 { 629 /* XXX Fixme, use a linear algorithm and not a while loop. */ 630 while ((kg->kg_runtime + kg->kg_slptime) > SCHED_SLP_RUN_MAX) { 631 kg->kg_runtime = (kg->kg_runtime / 5) * 4; 632 kg->kg_slptime = (kg->kg_slptime / 5) * 4; 633 } 634 } 635 636 static int 637 sched_interact_score(struct ksegrp *kg) 638 { 639 int div; 640 641 if (kg->kg_runtime > kg->kg_slptime) { 642 div = max(1, kg->kg_runtime / SCHED_INTERACT_HALF); 643 return (SCHED_INTERACT_HALF + 644 (SCHED_INTERACT_HALF - (kg->kg_slptime / div))); 645 } if (kg->kg_slptime > kg->kg_runtime) { 646 div = max(1, kg->kg_slptime / SCHED_INTERACT_HALF); 647 return (kg->kg_runtime / div); 648 } 649 650 /* 651 * This can happen if slptime and runtime are 0. 652 */ 653 return (0); 654 655 } 656 657 /* 658 * This is only somewhat accurate since given many processes of the same 659 * priority they will switch when their slices run out, which will be 660 * at most SCHED_SLICE_MAX. 661 */ 662 int 663 sched_rr_interval(void) 664 { 665 return (SCHED_SLICE_MAX); 666 } 667 668 void 669 sched_pctcpu_update(struct kse *ke) 670 { 671 /* 672 * Adjust counters and watermark for pctcpu calc. 673 */ 674 675 /* 676 * Shift the tick count out so that the divide doesn't round away 677 * our results. 678 */ 679 ke->ke_ticks <<= 10; 680 ke->ke_ticks = (ke->ke_ticks / (ke->ke_ltick - ke->ke_ftick)) * 681 SCHED_CPU_TICKS; 682 ke->ke_ticks >>= 10; 683 ke->ke_ltick = ticks; 684 ke->ke_ftick = ke->ke_ltick - SCHED_CPU_TICKS; 685 } 686 687 #ifdef SMP 688 /* XXX Should be changed to kseq_load_lowest() */ 689 int 690 sched_pickcpu(void) 691 { 692 struct kseq *kseq; 693 int load; 694 int cpu; 695 int i; 696 697 mtx_assert(&sched_lock, MA_OWNED); 698 if (!smp_started) 699 return (0); 700 701 load = 0; 702 cpu = 0; 703 704 for (i = 0; i < mp_maxid; i++) { 705 if (CPU_ABSENT(i)) 706 continue; 707 kseq = KSEQ_CPU(i); 708 if (kseq->ksq_load < load) { 709 cpu = i; 710 load = kseq->ksq_load; 711 } 712 } 713 714 CTR1(KTR_RUNQ, "sched_pickcpu: %d", cpu); 715 return (cpu); 716 } 717 #else 718 int 719 sched_pickcpu(void) 720 { 721 return (0); 722 } 723 #endif 724 725 void 726 sched_prio(struct thread *td, u_char prio) 727 { 728 struct kse *ke; 729 struct runq *rq; 730 731 mtx_assert(&sched_lock, MA_OWNED); 732 ke = td->td_kse; 733 td->td_priority = prio; 734 735 if (TD_ON_RUNQ(td)) { 736 rq = ke->ke_runq; 737 738 runq_remove(rq, ke); 739 runq_add(rq, ke); 740 } 741 } 742 743 void 744 sched_switchout(struct thread *td) 745 { 746 struct kse *ke; 747 748 mtx_assert(&sched_lock, MA_OWNED); 749 750 ke = td->td_kse; 751 752 td->td_last_kse = ke; 753 td->td_lastcpu = td->td_oncpu; 754 td->td_oncpu = NOCPU; 755 td->td_flags &= ~TDF_NEEDRESCHED; 756 757 if (TD_IS_RUNNING(td)) { 758 /* 759 * This queue is always correct except for idle threads which 760 * have a higher priority due to priority propagation. 761 */ 762 if (ke->ke_ksegrp->kg_pri_class == PRI_IDLE && 763 ke->ke_thread->td_priority > PRI_MIN_IDLE) 764 ke->ke_runq = KSEQ_SELF()->ksq_curr; 765 runq_add(ke->ke_runq, ke); 766 /* setrunqueue(td); */ 767 return; 768 } 769 if (ke->ke_runq) 770 kseq_rem(KSEQ_CPU(ke->ke_cpu), ke); 771 /* 772 * We will not be on the run queue. So we must be 773 * sleeping or similar. 774 */ 775 if (td->td_proc->p_flag & P_SA) 776 kse_reassign(ke); 777 } 778 779 void 780 sched_switchin(struct thread *td) 781 { 782 /* struct kse *ke = td->td_kse; */ 783 mtx_assert(&sched_lock, MA_OWNED); 784 785 td->td_oncpu = PCPU_GET(cpuid); 786 } 787 788 void 789 sched_nice(struct ksegrp *kg, int nice) 790 { 791 struct kse *ke; 792 struct thread *td; 793 struct kseq *kseq; 794 795 PROC_LOCK_ASSERT(kg->kg_proc, MA_OWNED); 796 mtx_assert(&sched_lock, MA_OWNED); 797 /* 798 * We need to adjust the nice counts for running KSEs. 799 */ 800 if (kg->kg_pri_class == PRI_TIMESHARE) 801 FOREACH_KSE_IN_GROUP(kg, ke) { 802 if (ke->ke_runq == NULL) 803 continue; 804 kseq = KSEQ_CPU(ke->ke_cpu); 805 kseq_nice_rem(kseq, kg->kg_nice); 806 kseq_nice_add(kseq, nice); 807 } 808 kg->kg_nice = nice; 809 sched_priority(kg); 810 FOREACH_THREAD_IN_GROUP(kg, td) 811 td->td_flags |= TDF_NEEDRESCHED; 812 } 813 814 void 815 sched_sleep(struct thread *td, u_char prio) 816 { 817 mtx_assert(&sched_lock, MA_OWNED); 818 819 td->td_slptime = ticks; 820 td->td_priority = prio; 821 822 CTR2(KTR_ULE, "sleep kse %p (tick: %d)", 823 td->td_kse, td->td_slptime); 824 } 825 826 void 827 sched_wakeup(struct thread *td) 828 { 829 mtx_assert(&sched_lock, MA_OWNED); 830 831 /* 832 * Let the kseg know how long we slept for. This is because process 833 * interactivity behavior is modeled in the kseg. 834 */ 835 if (td->td_slptime) { 836 struct ksegrp *kg; 837 int hzticks; 838 839 kg = td->td_ksegrp; 840 hzticks = ticks - td->td_slptime; 841 kg->kg_slptime += hzticks << 10; 842 sched_interact_update(kg); 843 sched_priority(kg); 844 if (td->td_kse) 845 sched_slice(td->td_kse); 846 CTR2(KTR_ULE, "wakeup kse %p (%d ticks)", 847 td->td_kse, hzticks); 848 td->td_slptime = 0; 849 } 850 setrunqueue(td); 851 if (td->td_priority < curthread->td_priority) 852 curthread->td_flags |= TDF_NEEDRESCHED; 853 } 854 855 /* 856 * Penalize the parent for creating a new child and initialize the child's 857 * priority. 858 */ 859 void 860 sched_fork(struct proc *p, struct proc *p1) 861 { 862 863 mtx_assert(&sched_lock, MA_OWNED); 864 865 sched_fork_ksegrp(FIRST_KSEGRP_IN_PROC(p), FIRST_KSEGRP_IN_PROC(p1)); 866 sched_fork_kse(FIRST_KSE_IN_PROC(p), FIRST_KSE_IN_PROC(p1)); 867 sched_fork_thread(FIRST_THREAD_IN_PROC(p), FIRST_THREAD_IN_PROC(p1)); 868 } 869 870 void 871 sched_fork_kse(struct kse *ke, struct kse *child) 872 { 873 874 child->ke_slice = 1; /* Attempt to quickly learn interactivity. */ 875 child->ke_cpu = ke->ke_cpu; /* sched_pickcpu(); */ 876 child->ke_runq = NULL; 877 878 /* 879 * Claim that we've been running for one second for statistical 880 * purposes. 881 */ 882 child->ke_ticks = 0; 883 child->ke_ltick = ticks; 884 child->ke_ftick = ticks - hz; 885 } 886 887 void 888 sched_fork_ksegrp(struct ksegrp *kg, struct ksegrp *child) 889 { 890 891 PROC_LOCK_ASSERT(child->kg_proc, MA_OWNED); 892 /* XXX Need something better here */ 893 894 child->kg_slptime = kg->kg_slptime; 895 child->kg_runtime = kg->kg_runtime; 896 kg->kg_runtime += tickincr << 10; 897 sched_interact_update(kg); 898 899 child->kg_user_pri = kg->kg_user_pri; 900 child->kg_nice = kg->kg_nice; 901 } 902 903 void 904 sched_fork_thread(struct thread *td, struct thread *child) 905 { 906 } 907 908 void 909 sched_class(struct ksegrp *kg, int class) 910 { 911 struct kseq *kseq; 912 struct kse *ke; 913 914 mtx_assert(&sched_lock, MA_OWNED); 915 if (kg->kg_pri_class == class) 916 return; 917 918 FOREACH_KSE_IN_GROUP(kg, ke) { 919 if (ke->ke_state != KES_ONRUNQ && 920 ke->ke_state != KES_THREAD) 921 continue; 922 kseq = KSEQ_CPU(ke->ke_cpu); 923 924 kseq->ksq_loads[PRI_BASE(kg->kg_pri_class)]--; 925 kseq->ksq_loads[PRI_BASE(class)]++; 926 927 if (kg->kg_pri_class == PRI_TIMESHARE) 928 kseq_nice_rem(kseq, kg->kg_nice); 929 else if (class == PRI_TIMESHARE) 930 kseq_nice_add(kseq, kg->kg_nice); 931 } 932 933 kg->kg_pri_class = class; 934 } 935 936 /* 937 * Return some of the child's priority and interactivity to the parent. 938 */ 939 void 940 sched_exit(struct proc *p, struct proc *child) 941 { 942 /* XXX Need something better here */ 943 mtx_assert(&sched_lock, MA_OWNED); 944 sched_exit_kse(FIRST_KSE_IN_PROC(p), FIRST_KSE_IN_PROC(child)); 945 sched_exit_ksegrp(FIRST_KSEGRP_IN_PROC(p), FIRST_KSEGRP_IN_PROC(child)); 946 } 947 948 void 949 sched_exit_kse(struct kse *ke, struct kse *child) 950 { 951 kseq_rem(KSEQ_CPU(child->ke_cpu), child); 952 } 953 954 void 955 sched_exit_ksegrp(struct ksegrp *kg, struct ksegrp *child) 956 { 957 /* kg->kg_slptime += child->kg_slptime; */ 958 kg->kg_runtime += child->kg_runtime; 959 sched_interact_update(kg); 960 } 961 962 void 963 sched_exit_thread(struct thread *td, struct thread *child) 964 { 965 } 966 967 void 968 sched_clock(struct kse *ke) 969 { 970 struct kseq *kseq; 971 struct ksegrp *kg; 972 struct thread *td; 973 #if 0 974 struct kse *nke; 975 #endif 976 977 /* 978 * sched_setup() apparently happens prior to stathz being set. We 979 * need to resolve the timers earlier in the boot so we can avoid 980 * calculating this here. 981 */ 982 if (realstathz == 0) { 983 realstathz = stathz ? stathz : hz; 984 tickincr = hz / realstathz; 985 /* 986 * XXX This does not work for values of stathz that are much 987 * larger than hz. 988 */ 989 if (tickincr == 0) 990 tickincr = 1; 991 } 992 993 td = ke->ke_thread; 994 kg = ke->ke_ksegrp; 995 996 mtx_assert(&sched_lock, MA_OWNED); 997 KASSERT((td != NULL), ("schedclock: null thread pointer")); 998 999 /* Adjust ticks for pctcpu */ 1000 ke->ke_ticks++; 1001 ke->ke_ltick = ticks; 1002 1003 /* Go up to one second beyond our max and then trim back down */ 1004 if (ke->ke_ftick + SCHED_CPU_TICKS + hz < ke->ke_ltick) 1005 sched_pctcpu_update(ke); 1006 1007 if (td->td_flags & TDF_IDLETD) 1008 return; 1009 1010 CTR4(KTR_ULE, "Tick kse %p (slice: %d, slptime: %d, runtime: %d)", 1011 ke, ke->ke_slice, kg->kg_slptime >> 10, kg->kg_runtime >> 10); 1012 1013 /* 1014 * We only do slicing code for TIMESHARE ksegrps. 1015 */ 1016 if (kg->kg_pri_class != PRI_TIMESHARE) 1017 return; 1018 /* 1019 * Check for a higher priority task on the run queue. This can happen 1020 * on SMP if another processor woke up a process on our runq. 1021 */ 1022 kseq = KSEQ_SELF(); 1023 #if 0 1024 if (kseq->ksq_load > 1 && (nke = kseq_choose(kseq)) != NULL) { 1025 if (sched_strict && 1026 nke->ke_thread->td_priority < td->td_priority) 1027 td->td_flags |= TDF_NEEDRESCHED; 1028 else if (nke->ke_thread->td_priority < 1029 td->td_priority SCHED_PRIO_SLOP) 1030 1031 if (nke->ke_thread->td_priority < td->td_priority) 1032 td->td_flags |= TDF_NEEDRESCHED; 1033 } 1034 #endif 1035 /* 1036 * We used a tick charge it to the ksegrp so that we can compute our 1037 * interactivity. 1038 */ 1039 kg->kg_runtime += tickincr << 10; 1040 sched_interact_update(kg); 1041 1042 /* 1043 * We used up one time slice. 1044 */ 1045 ke->ke_slice--; 1046 #ifdef SMP 1047 kseq->ksq_rslices--; 1048 #endif 1049 1050 if (ke->ke_slice > 0) 1051 return; 1052 /* 1053 * We're out of time, recompute priorities and requeue. 1054 */ 1055 kseq_rem(kseq, ke); 1056 sched_priority(kg); 1057 sched_slice(ke); 1058 if (SCHED_CURR(kg, ke)) 1059 ke->ke_runq = kseq->ksq_curr; 1060 else 1061 ke->ke_runq = kseq->ksq_next; 1062 kseq_add(kseq, ke); 1063 td->td_flags |= TDF_NEEDRESCHED; 1064 } 1065 1066 int 1067 sched_runnable(void) 1068 { 1069 struct kseq *kseq; 1070 int load; 1071 1072 load = 1; 1073 1074 mtx_lock_spin(&sched_lock); 1075 kseq = KSEQ_SELF(); 1076 1077 if (kseq->ksq_load) 1078 goto out; 1079 #ifdef SMP 1080 /* 1081 * For SMP we may steal other processor's KSEs. Just search until we 1082 * verify that at least on other cpu has a runnable task. 1083 */ 1084 if (smp_started) { 1085 int i; 1086 1087 for (i = 0; i < mp_maxid; i++) { 1088 if (CPU_ABSENT(i)) 1089 continue; 1090 kseq = KSEQ_CPU(i); 1091 if (kseq->ksq_load > 1) 1092 goto out; 1093 } 1094 } 1095 #endif 1096 load = 0; 1097 out: 1098 mtx_unlock_spin(&sched_lock); 1099 return (load); 1100 } 1101 1102 void 1103 sched_userret(struct thread *td) 1104 { 1105 struct ksegrp *kg; 1106 struct kseq *kseq; 1107 struct kse *ke; 1108 1109 kg = td->td_ksegrp; 1110 1111 if (td->td_priority != kg->kg_user_pri) { 1112 mtx_lock_spin(&sched_lock); 1113 td->td_priority = kg->kg_user_pri; 1114 kseq = KSEQ_SELF(); 1115 if (td->td_ksegrp->kg_pri_class == PRI_TIMESHARE && 1116 kseq->ksq_load > 1 && 1117 (ke = kseq_choose(kseq)) != NULL && 1118 ke->ke_thread->td_priority < td->td_priority) 1119 curthread->td_flags |= TDF_NEEDRESCHED; 1120 mtx_unlock_spin(&sched_lock); 1121 } 1122 } 1123 1124 struct kse * 1125 sched_choose(void) 1126 { 1127 struct kseq *kseq; 1128 struct kse *ke; 1129 1130 mtx_assert(&sched_lock, MA_OWNED); 1131 #ifdef SMP 1132 retry: 1133 #endif 1134 kseq = KSEQ_SELF(); 1135 ke = kseq_choose(kseq); 1136 if (ke) { 1137 runq_remove(ke->ke_runq, ke); 1138 ke->ke_state = KES_THREAD; 1139 1140 if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) { 1141 CTR4(KTR_ULE, "Run kse %p from %p (slice: %d, pri: %d)", 1142 ke, ke->ke_runq, ke->ke_slice, 1143 ke->ke_thread->td_priority); 1144 } 1145 return (ke); 1146 } 1147 1148 #ifdef SMP 1149 if (smp_started) { 1150 /* 1151 * Find the cpu with the highest load and steal one proc. 1152 */ 1153 if ((kseq = kseq_load_highest()) == NULL) 1154 return (NULL); 1155 1156 /* 1157 * Remove this kse from this kseq and runq and then requeue 1158 * on the current processor. Then we will dequeue it 1159 * normally above. 1160 */ 1161 kseq_move(kseq, PCPU_GET(cpuid)); 1162 goto retry; 1163 } 1164 #endif 1165 1166 return (NULL); 1167 } 1168 1169 void 1170 sched_add(struct kse *ke) 1171 { 1172 struct kseq *kseq; 1173 struct ksegrp *kg; 1174 1175 mtx_assert(&sched_lock, MA_OWNED); 1176 KASSERT((ke->ke_thread != NULL), ("sched_add: No thread on KSE")); 1177 KASSERT((ke->ke_thread->td_kse != NULL), 1178 ("sched_add: No KSE on thread")); 1179 KASSERT(ke->ke_state != KES_ONRUNQ, 1180 ("sched_add: kse %p (%s) already in run queue", ke, 1181 ke->ke_proc->p_comm)); 1182 KASSERT(ke->ke_proc->p_sflag & PS_INMEM, 1183 ("sched_add: process swapped out")); 1184 KASSERT(ke->ke_runq == NULL, 1185 ("sched_add: KSE %p is still assigned to a run queue", ke)); 1186 1187 kg = ke->ke_ksegrp; 1188 1189 switch (PRI_BASE(kg->kg_pri_class)) { 1190 case PRI_ITHD: 1191 case PRI_REALTIME: 1192 kseq = KSEQ_SELF(); 1193 ke->ke_runq = kseq->ksq_curr; 1194 ke->ke_slice = SCHED_SLICE_MAX; 1195 ke->ke_cpu = PCPU_GET(cpuid); 1196 break; 1197 case PRI_TIMESHARE: 1198 kseq = KSEQ_CPU(ke->ke_cpu); 1199 if (SCHED_CURR(kg, ke)) 1200 ke->ke_runq = kseq->ksq_curr; 1201 else 1202 ke->ke_runq = kseq->ksq_next; 1203 break; 1204 case PRI_IDLE: 1205 kseq = KSEQ_CPU(ke->ke_cpu); 1206 /* 1207 * This is for priority prop. 1208 */ 1209 if (ke->ke_thread->td_priority > PRI_MIN_IDLE) 1210 ke->ke_runq = kseq->ksq_curr; 1211 else 1212 ke->ke_runq = &kseq->ksq_idle; 1213 ke->ke_slice = SCHED_SLICE_MIN; 1214 break; 1215 default: 1216 panic("Unknown pri class.\n"); 1217 break; 1218 } 1219 1220 ke->ke_ksegrp->kg_runq_kses++; 1221 ke->ke_state = KES_ONRUNQ; 1222 1223 runq_add(ke->ke_runq, ke); 1224 kseq_add(kseq, ke); 1225 } 1226 1227 void 1228 sched_rem(struct kse *ke) 1229 { 1230 struct kseq *kseq; 1231 1232 mtx_assert(&sched_lock, MA_OWNED); 1233 KASSERT((ke->ke_state == KES_ONRUNQ), ("KSE not on run queue")); 1234 1235 ke->ke_state = KES_THREAD; 1236 ke->ke_ksegrp->kg_runq_kses--; 1237 kseq = KSEQ_CPU(ke->ke_cpu); 1238 runq_remove(ke->ke_runq, ke); 1239 kseq_rem(kseq, ke); 1240 } 1241 1242 fixpt_t 1243 sched_pctcpu(struct kse *ke) 1244 { 1245 fixpt_t pctcpu; 1246 1247 pctcpu = 0; 1248 1249 mtx_lock_spin(&sched_lock); 1250 if (ke->ke_ticks) { 1251 int rtick; 1252 1253 /* 1254 * Don't update more frequently than twice a second. Allowing 1255 * this causes the cpu usage to decay away too quickly due to 1256 * rounding errors. 1257 */ 1258 if (ke->ke_ltick < (ticks - (hz / 2))) 1259 sched_pctcpu_update(ke); 1260 1261 /* How many rtick per second ? */ 1262 rtick = min(ke->ke_ticks / SCHED_CPU_TIME, SCHED_CPU_TICKS); 1263 pctcpu = (FSCALE * ((FSCALE * rtick)/realstathz)) >> FSHIFT; 1264 } 1265 1266 ke->ke_proc->p_swtime = ke->ke_ltick - ke->ke_ftick; 1267 mtx_unlock_spin(&sched_lock); 1268 1269 return (pctcpu); 1270 } 1271 1272 int 1273 sched_sizeof_kse(void) 1274 { 1275 return (sizeof(struct kse) + sizeof(struct ke_sched)); 1276 } 1277 1278 int 1279 sched_sizeof_ksegrp(void) 1280 { 1281 return (sizeof(struct ksegrp) + sizeof(struct kg_sched)); 1282 } 1283 1284 int 1285 sched_sizeof_proc(void) 1286 { 1287 return (sizeof(struct proc)); 1288 } 1289 1290 int 1291 sched_sizeof_thread(void) 1292 { 1293 return (sizeof(struct thread) + sizeof(struct td_sched)); 1294 } 1295