1 /* $OpenBSD: sched_bsd.c,v 1.73 2022/12/05 23:18:37 deraadt Exp $ */ 2 /* $NetBSD: kern_synch.c,v 1.37 1996/04/22 01:38:37 christos Exp $ */ 3 4 /*- 5 * Copyright (c) 1982, 1986, 1990, 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)kern_synch.c 8.6 (Berkeley) 1/21/94 38 */ 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/proc.h> 43 #include <sys/kernel.h> 44 #include <sys/malloc.h> 45 #include <sys/resourcevar.h> 46 #include <uvm/uvm_extern.h> 47 #include <sys/sched.h> 48 #include <sys/timeout.h> 49 #include <sys/smr.h> 50 #include <sys/tracepoint.h> 51 52 #ifdef KTRACE 53 #include <sys/ktrace.h> 54 #endif 55 56 57 int lbolt; /* once a second sleep address */ 58 int rrticks_init; /* # of hardclock ticks per roundrobin() */ 59 60 #ifdef MULTIPROCESSOR 61 struct __mp_lock sched_lock; 62 #endif 63 64 void schedcpu(void *); 65 uint32_t decay_aftersleep(uint32_t, uint32_t); 66 67 /* 68 * Force switch among equal priority processes every 100ms. 69 */ 70 void 71 roundrobin(struct cpu_info *ci) 72 { 73 struct schedstate_percpu *spc = &ci->ci_schedstate; 74 75 spc->spc_rrticks = rrticks_init; 76 77 if (ci->ci_curproc != NULL) { 78 if (spc->spc_schedflags & SPCF_SEENRR) { 79 /* 80 * The process has already been through a roundrobin 81 * without switching and may be hogging the CPU. 82 * Indicate that the process should yield. 83 */ 84 atomic_setbits_int(&spc->spc_schedflags, 85 SPCF_SHOULDYIELD); 86 } else { 87 atomic_setbits_int(&spc->spc_schedflags, 88 SPCF_SEENRR); 89 } 90 } 91 92 if (spc->spc_nrun) 93 need_resched(ci); 94 } 95 96 /* 97 * Constants for digital decay and forget: 98 * 90% of (p_estcpu) usage in 5 * loadav time 99 * 95% of (p_pctcpu) usage in 60 seconds (load insensitive) 100 * Note that, as ps(1) mentions, this can let percentages 101 * total over 100% (I've seen 137.9% for 3 processes). 102 * 103 * Note that hardclock updates p_estcpu and p_cpticks independently. 104 * 105 * We wish to decay away 90% of p_estcpu in (5 * loadavg) seconds. 106 * That is, the system wants to compute a value of decay such 107 * that the following for loop: 108 * for (i = 0; i < (5 * loadavg); i++) 109 * p_estcpu *= decay; 110 * will compute 111 * p_estcpu *= 0.1; 112 * for all values of loadavg: 113 * 114 * Mathematically this loop can be expressed by saying: 115 * decay ** (5 * loadavg) ~= .1 116 * 117 * The system computes decay as: 118 * decay = (2 * loadavg) / (2 * loadavg + 1) 119 * 120 * We wish to prove that the system's computation of decay 121 * will always fulfill the equation: 122 * decay ** (5 * loadavg) ~= .1 123 * 124 * If we compute b as: 125 * b = 2 * loadavg 126 * then 127 * decay = b / (b + 1) 128 * 129 * We now need to prove two things: 130 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1) 131 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg) 132 * 133 * Facts: 134 * For x close to zero, exp(x) =~ 1 + x, since 135 * exp(x) = 0! + x**1/1! + x**2/2! + ... . 136 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b. 137 * For x close to zero, ln(1+x) =~ x, since 138 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1 139 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1). 140 * ln(.1) =~ -2.30 141 * 142 * Proof of (1): 143 * Solve (factor)**(power) =~ .1 given power (5*loadav): 144 * solving for factor, 145 * ln(factor) =~ (-2.30/5*loadav), or 146 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) = 147 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED 148 * 149 * Proof of (2): 150 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)): 151 * solving for power, 152 * power*ln(b/(b+1)) =~ -2.30, or 153 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED 154 * 155 * Actual power values for the implemented algorithm are as follows: 156 * loadav: 1 2 3 4 157 * power: 5.68 10.32 14.94 19.55 158 */ 159 160 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */ 161 #define loadfactor(loadav) (2 * (loadav)) 162 #define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE)) 163 164 /* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ 165 fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 166 167 /* 168 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 169 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 170 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 171 * 172 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 173 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 174 * 175 * If you don't want to bother with the faster/more-accurate formula, you 176 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 177 * (more general) method of calculating the %age of CPU used by a process. 178 */ 179 #define CCPU_SHIFT 11 180 181 /* 182 * Recompute process priorities, every second. 183 */ 184 void 185 schedcpu(void *arg) 186 { 187 struct timeout *to = (struct timeout *)arg; 188 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 189 struct proc *p; 190 int s; 191 unsigned int newcpu; 192 int phz; 193 194 /* 195 * If we have a statistics clock, use that to calculate CPU 196 * time, otherwise revert to using the profiling clock (which, 197 * in turn, defaults to hz if there is no separate profiling 198 * clock available) 199 */ 200 phz = stathz ? stathz : profhz; 201 KASSERT(phz); 202 203 LIST_FOREACH(p, &allproc, p_list) { 204 /* 205 * Idle threads are never placed on the runqueue, 206 * therefore computing their priority is pointless. 207 */ 208 if (p->p_cpu != NULL && 209 p->p_cpu->ci_schedstate.spc_idleproc == p) 210 continue; 211 /* 212 * Increment sleep time (if sleeping). We ignore overflow. 213 */ 214 if (p->p_stat == SSLEEP || p->p_stat == SSTOP) 215 p->p_slptime++; 216 p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT; 217 /* 218 * If the process has slept the entire second, 219 * stop recalculating its priority until it wakes up. 220 */ 221 if (p->p_slptime > 1) 222 continue; 223 SCHED_LOCK(s); 224 /* 225 * p_pctcpu is only for diagnostic tools such as ps. 226 */ 227 #if (FSHIFT >= CCPU_SHIFT) 228 p->p_pctcpu += (phz == 100)? 229 ((fixpt_t) p->p_cpticks) << (FSHIFT - CCPU_SHIFT): 230 100 * (((fixpt_t) p->p_cpticks) 231 << (FSHIFT - CCPU_SHIFT)) / phz; 232 #else 233 p->p_pctcpu += ((FSCALE - ccpu) * 234 (p->p_cpticks * FSCALE / phz)) >> FSHIFT; 235 #endif 236 p->p_cpticks = 0; 237 newcpu = (u_int) decay_cpu(loadfac, p->p_estcpu); 238 setpriority(p, newcpu, p->p_p->ps_nice); 239 240 if (p->p_stat == SRUN && 241 (p->p_runpri / SCHED_PPQ) != (p->p_usrpri / SCHED_PPQ)) { 242 remrunqueue(p); 243 setrunqueue(p->p_cpu, p, p->p_usrpri); 244 } 245 SCHED_UNLOCK(s); 246 } 247 uvm_meter(); 248 wakeup(&lbolt); 249 timeout_add_sec(to, 1); 250 } 251 252 /* 253 * Recalculate the priority of a process after it has slept for a while. 254 * For all load averages >= 1 and max p_estcpu of 255, sleeping for at 255 * least six times the loadfactor will decay p_estcpu to zero. 256 */ 257 uint32_t 258 decay_aftersleep(uint32_t estcpu, uint32_t slptime) 259 { 260 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 261 uint32_t newcpu; 262 263 if (slptime > 5 * loadfac) 264 newcpu = 0; 265 else { 266 newcpu = estcpu; 267 slptime--; /* the first time was done in schedcpu */ 268 while (newcpu && --slptime) 269 newcpu = decay_cpu(loadfac, newcpu); 270 271 } 272 273 return (newcpu); 274 } 275 276 /* 277 * General yield call. Puts the current process back on its run queue and 278 * performs a voluntary context switch. 279 */ 280 void 281 yield(void) 282 { 283 struct proc *p = curproc; 284 int s; 285 286 SCHED_LOCK(s); 287 setrunqueue(p->p_cpu, p, p->p_usrpri); 288 p->p_ru.ru_nvcsw++; 289 mi_switch(); 290 SCHED_UNLOCK(s); 291 } 292 293 /* 294 * General preemption call. Puts the current process back on its run queue 295 * and performs an involuntary context switch. If a process is supplied, 296 * we switch to that process. Otherwise, we use the normal process selection 297 * criteria. 298 */ 299 void 300 preempt(void) 301 { 302 struct proc *p = curproc; 303 int s; 304 305 SCHED_LOCK(s); 306 setrunqueue(p->p_cpu, p, p->p_usrpri); 307 p->p_ru.ru_nivcsw++; 308 mi_switch(); 309 SCHED_UNLOCK(s); 310 } 311 312 void 313 mi_switch(void) 314 { 315 struct schedstate_percpu *spc = &curcpu()->ci_schedstate; 316 struct proc *p = curproc; 317 struct proc *nextproc; 318 struct process *pr = p->p_p; 319 struct timespec ts; 320 #ifdef MULTIPROCESSOR 321 int hold_count; 322 int sched_count; 323 #endif 324 325 assertwaitok(); 326 KASSERT(p->p_stat != SONPROC); 327 328 SCHED_ASSERT_LOCKED(); 329 330 #ifdef MULTIPROCESSOR 331 /* 332 * Release the kernel_lock, as we are about to yield the CPU. 333 */ 334 sched_count = __mp_release_all_but_one(&sched_lock); 335 if (_kernel_lock_held()) 336 hold_count = __mp_release_all(&kernel_lock); 337 else 338 hold_count = 0; 339 #endif 340 341 /* 342 * Compute the amount of time during which the current 343 * process was running, and add that to its total so far. 344 */ 345 nanouptime(&ts); 346 if (timespeccmp(&ts, &spc->spc_runtime, <)) { 347 #if 0 348 printf("uptime is not monotonic! " 349 "ts=%lld.%09lu, runtime=%lld.%09lu\n", 350 (long long)tv.tv_sec, tv.tv_nsec, 351 (long long)spc->spc_runtime.tv_sec, 352 spc->spc_runtime.tv_nsec); 353 #endif 354 } else { 355 timespecsub(&ts, &spc->spc_runtime, &ts); 356 timespecadd(&p->p_rtime, &ts, &p->p_rtime); 357 } 358 359 /* add the time counts for this thread to the process's total */ 360 tuagg_unlocked(pr, p); 361 362 /* 363 * Process is about to yield the CPU; clear the appropriate 364 * scheduling flags. 365 */ 366 atomic_clearbits_int(&spc->spc_schedflags, SPCF_SWITCHCLEAR); 367 368 nextproc = sched_chooseproc(); 369 370 if (p != nextproc) { 371 uvmexp.swtch++; 372 TRACEPOINT(sched, off__cpu, nextproc->p_tid + THREAD_PID_OFFSET, 373 nextproc->p_p->ps_pid); 374 cpu_switchto(p, nextproc); 375 TRACEPOINT(sched, on__cpu, NULL); 376 } else { 377 TRACEPOINT(sched, remain__cpu, NULL); 378 p->p_stat = SONPROC; 379 } 380 381 clear_resched(curcpu()); 382 383 SCHED_ASSERT_LOCKED(); 384 385 /* 386 * To preserve lock ordering, we need to release the sched lock 387 * and grab it after we grab the big lock. 388 * In the future, when the sched lock isn't recursive, we'll 389 * just release it here. 390 */ 391 #ifdef MULTIPROCESSOR 392 __mp_unlock(&sched_lock); 393 #endif 394 395 SCHED_ASSERT_UNLOCKED(); 396 397 smr_idle(); 398 399 /* 400 * We're running again; record our new start time. We might 401 * be running on a new CPU now, so don't use the cache'd 402 * schedstate_percpu pointer. 403 */ 404 KASSERT(p->p_cpu == curcpu()); 405 406 nanouptime(&p->p_cpu->ci_schedstate.spc_runtime); 407 408 #ifdef MULTIPROCESSOR 409 /* 410 * Reacquire the kernel_lock now. We do this after we've 411 * released the scheduler lock to avoid deadlock, and before 412 * we reacquire the interlock and the scheduler lock. 413 */ 414 if (hold_count) 415 __mp_acquire_count(&kernel_lock, hold_count); 416 __mp_acquire_count(&sched_lock, sched_count + 1); 417 #endif 418 } 419 420 /* 421 * Change process state to be runnable, 422 * placing it on the run queue. 423 */ 424 void 425 setrunnable(struct proc *p) 426 { 427 struct process *pr = p->p_p; 428 u_char prio; 429 430 SCHED_ASSERT_LOCKED(); 431 432 switch (p->p_stat) { 433 case 0: 434 case SRUN: 435 case SONPROC: 436 case SDEAD: 437 case SIDL: 438 default: 439 panic("setrunnable"); 440 case SSTOP: 441 /* 442 * If we're being traced (possibly because someone attached us 443 * while we were stopped), check for a signal from the debugger. 444 */ 445 if ((pr->ps_flags & PS_TRACED) != 0 && pr->ps_xsig != 0) 446 atomic_setbits_int(&p->p_siglist, sigmask(pr->ps_xsig)); 447 prio = p->p_usrpri; 448 unsleep(p); 449 break; 450 case SSLEEP: 451 prio = p->p_slppri; 452 unsleep(p); /* e.g. when sending signals */ 453 break; 454 } 455 setrunqueue(NULL, p, prio); 456 if (p->p_slptime > 1) { 457 uint32_t newcpu; 458 459 newcpu = decay_aftersleep(p->p_estcpu, p->p_slptime); 460 setpriority(p, newcpu, pr->ps_nice); 461 } 462 p->p_slptime = 0; 463 } 464 465 /* 466 * Compute the priority of a process. 467 */ 468 void 469 setpriority(struct proc *p, uint32_t newcpu, uint8_t nice) 470 { 471 unsigned int newprio; 472 473 newprio = min((PUSER + newcpu + NICE_WEIGHT * (nice - NZERO)), MAXPRI); 474 475 SCHED_ASSERT_LOCKED(); 476 p->p_estcpu = newcpu; 477 p->p_usrpri = newprio; 478 } 479 480 /* 481 * We adjust the priority of the current process. The priority of a process 482 * gets worse as it accumulates CPU time. The cpu usage estimator (p_estcpu) 483 * is increased here. The formula for computing priorities (in kern_synch.c) 484 * will compute a different value each time p_estcpu increases. This can 485 * cause a switch, but unless the priority crosses a PPQ boundary the actual 486 * queue will not change. The cpu usage estimator ramps up quite quickly 487 * when the process is running (linearly), and decays away exponentially, at 488 * a rate which is proportionally slower when the system is busy. The basic 489 * principle is that the system will 90% forget that the process used a lot 490 * of CPU time in 5 * loadav seconds. This causes the system to favor 491 * processes which haven't run much recently, and to round-robin among other 492 * processes. 493 */ 494 void 495 schedclock(struct proc *p) 496 { 497 struct cpu_info *ci = curcpu(); 498 struct schedstate_percpu *spc = &ci->ci_schedstate; 499 uint32_t newcpu; 500 int s; 501 502 if (p == spc->spc_idleproc || spc->spc_spinning) 503 return; 504 505 SCHED_LOCK(s); 506 newcpu = ESTCPULIM(p->p_estcpu + 1); 507 setpriority(p, newcpu, p->p_p->ps_nice); 508 SCHED_UNLOCK(s); 509 } 510 511 void (*cpu_setperf)(int); 512 513 #define PERFPOL_MANUAL 0 514 #define PERFPOL_AUTO 1 515 #define PERFPOL_HIGH 2 516 int perflevel = 100; 517 int perfpolicy = PERFPOL_AUTO; 518 519 #ifndef SMALL_KERNEL 520 /* 521 * The code below handles CPU throttling. 522 */ 523 #include <sys/sysctl.h> 524 525 void setperf_auto(void *); 526 struct timeout setperf_to = TIMEOUT_INITIALIZER(setperf_auto, NULL); 527 extern int hw_power; 528 529 void 530 setperf_auto(void *v) 531 { 532 static uint64_t *idleticks, *totalticks; 533 static int downbeats; 534 int i, j = 0; 535 int speedup = 0; 536 CPU_INFO_ITERATOR cii; 537 struct cpu_info *ci; 538 uint64_t idle, total, allidle = 0, alltotal = 0; 539 540 if (perfpolicy != PERFPOL_AUTO) 541 return; 542 543 if (cpu_setperf == NULL) 544 return; 545 546 if (hw_power) { 547 speedup = 1; 548 goto faster; 549 } 550 551 if (!idleticks) 552 if (!(idleticks = mallocarray(ncpusfound, sizeof(*idleticks), 553 M_DEVBUF, M_NOWAIT | M_ZERO))) 554 return; 555 if (!totalticks) 556 if (!(totalticks = mallocarray(ncpusfound, sizeof(*totalticks), 557 M_DEVBUF, M_NOWAIT | M_ZERO))) { 558 free(idleticks, M_DEVBUF, 559 sizeof(*idleticks) * ncpusfound); 560 return; 561 } 562 CPU_INFO_FOREACH(cii, ci) { 563 if (!cpu_is_online(ci)) 564 continue; 565 total = 0; 566 for (i = 0; i < CPUSTATES; i++) { 567 total += ci->ci_schedstate.spc_cp_time[i]; 568 } 569 total -= totalticks[j]; 570 idle = ci->ci_schedstate.spc_cp_time[CP_IDLE] - idleticks[j]; 571 if (idle < total / 3) 572 speedup = 1; 573 alltotal += total; 574 allidle += idle; 575 idleticks[j] += idle; 576 totalticks[j] += total; 577 j++; 578 } 579 if (allidle < alltotal / 2) 580 speedup = 1; 581 if (speedup && downbeats < 5) 582 downbeats++; 583 584 if (speedup && perflevel != 100) { 585 faster: 586 perflevel = 100; 587 cpu_setperf(perflevel); 588 } else if (!speedup && perflevel != 0 && --downbeats <= 0) { 589 perflevel = 0; 590 cpu_setperf(perflevel); 591 } 592 593 timeout_add_msec(&setperf_to, 100); 594 } 595 596 int 597 sysctl_hwsetperf(void *oldp, size_t *oldlenp, void *newp, size_t newlen) 598 { 599 int err; 600 601 if (!cpu_setperf) 602 return EOPNOTSUPP; 603 604 if (perfpolicy != PERFPOL_MANUAL) 605 return sysctl_rdint(oldp, oldlenp, newp, perflevel); 606 607 err = sysctl_int_bounded(oldp, oldlenp, newp, newlen, 608 &perflevel, 0, 100); 609 if (err) 610 return err; 611 612 if (newp != NULL) 613 cpu_setperf(perflevel); 614 615 return 0; 616 } 617 618 int 619 sysctl_hwperfpolicy(void *oldp, size_t *oldlenp, void *newp, size_t newlen) 620 { 621 char policy[32]; 622 int err; 623 624 if (!cpu_setperf) 625 return EOPNOTSUPP; 626 627 switch (perfpolicy) { 628 case PERFPOL_MANUAL: 629 strlcpy(policy, "manual", sizeof(policy)); 630 break; 631 case PERFPOL_AUTO: 632 strlcpy(policy, "auto", sizeof(policy)); 633 break; 634 case PERFPOL_HIGH: 635 strlcpy(policy, "high", sizeof(policy)); 636 break; 637 default: 638 strlcpy(policy, "unknown", sizeof(policy)); 639 break; 640 } 641 642 if (newp == NULL) 643 return sysctl_rdstring(oldp, oldlenp, newp, policy); 644 645 err = sysctl_string(oldp, oldlenp, newp, newlen, policy, sizeof(policy)); 646 if (err) 647 return err; 648 if (strcmp(policy, "manual") == 0) 649 perfpolicy = PERFPOL_MANUAL; 650 else if (strcmp(policy, "auto") == 0) 651 perfpolicy = PERFPOL_AUTO; 652 else if (strcmp(policy, "high") == 0) 653 perfpolicy = PERFPOL_HIGH; 654 else 655 return EINVAL; 656 657 if (perfpolicy == PERFPOL_AUTO) { 658 timeout_add_msec(&setperf_to, 200); 659 } else if (perfpolicy == PERFPOL_HIGH) { 660 perflevel = 100; 661 cpu_setperf(perflevel); 662 } 663 return 0; 664 } 665 #endif 666 667 void 668 scheduler_start(void) 669 { 670 static struct timeout schedcpu_to; 671 672 /* 673 * We avoid polluting the global namespace by keeping the scheduler 674 * timeouts static in this function. 675 * We setup the timeout here and kick schedcpu once to make it do 676 * its job. 677 */ 678 timeout_set(&schedcpu_to, schedcpu, &schedcpu_to); 679 680 rrticks_init = hz / 10; 681 schedcpu(&schedcpu_to); 682 683 #ifndef SMALL_KERNEL 684 if (perfpolicy == PERFPOL_AUTO) 685 timeout_add_msec(&setperf_to, 200); 686 #endif 687 } 688 689