1 /* $OpenBSD: sched_bsd.c,v 1.50 2019/02/26 14:24:21 visa 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/signalvar.h> 46 #include <sys/resourcevar.h> 47 #include <uvm/uvm_extern.h> 48 #include <sys/sched.h> 49 #include <sys/timeout.h> 50 #include <sys/smr.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 void updatepri(struct proc *); 66 67 void 68 scheduler_start(void) 69 { 70 static struct timeout schedcpu_to; 71 72 /* 73 * We avoid polluting the global namespace by keeping the scheduler 74 * timeouts static in this function. 75 * We setup the timeout here and kick schedcpu once to make it do 76 * its job. 77 */ 78 timeout_set(&schedcpu_to, schedcpu, &schedcpu_to); 79 80 rrticks_init = hz / 10; 81 schedcpu(&schedcpu_to); 82 } 83 84 /* 85 * Force switch among equal priority processes every 100ms. 86 */ 87 void 88 roundrobin(struct cpu_info *ci) 89 { 90 struct schedstate_percpu *spc = &ci->ci_schedstate; 91 92 spc->spc_rrticks = rrticks_init; 93 94 if (ci->ci_curproc != NULL) { 95 if (spc->spc_schedflags & SPCF_SEENRR) { 96 /* 97 * The process has already been through a roundrobin 98 * without switching and may be hogging the CPU. 99 * Indicate that the process should yield. 100 */ 101 atomic_setbits_int(&spc->spc_schedflags, 102 SPCF_SHOULDYIELD); 103 } else { 104 atomic_setbits_int(&spc->spc_schedflags, 105 SPCF_SEENRR); 106 } 107 } 108 109 if (spc->spc_nrun) 110 need_resched(ci); 111 } 112 113 /* 114 * Constants for digital decay and forget: 115 * 90% of (p_estcpu) usage in 5 * loadav time 116 * 95% of (p_pctcpu) usage in 60 seconds (load insensitive) 117 * Note that, as ps(1) mentions, this can let percentages 118 * total over 100% (I've seen 137.9% for 3 processes). 119 * 120 * Note that hardclock updates p_estcpu and p_cpticks independently. 121 * 122 * We wish to decay away 90% of p_estcpu in (5 * loadavg) seconds. 123 * That is, the system wants to compute a value of decay such 124 * that the following for loop: 125 * for (i = 0; i < (5 * loadavg); i++) 126 * p_estcpu *= decay; 127 * will compute 128 * p_estcpu *= 0.1; 129 * for all values of loadavg: 130 * 131 * Mathematically this loop can be expressed by saying: 132 * decay ** (5 * loadavg) ~= .1 133 * 134 * The system computes decay as: 135 * decay = (2 * loadavg) / (2 * loadavg + 1) 136 * 137 * We wish to prove that the system's computation of decay 138 * will always fulfill the equation: 139 * decay ** (5 * loadavg) ~= .1 140 * 141 * If we compute b as: 142 * b = 2 * loadavg 143 * then 144 * decay = b / (b + 1) 145 * 146 * We now need to prove two things: 147 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1) 148 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg) 149 * 150 * Facts: 151 * For x close to zero, exp(x) =~ 1 + x, since 152 * exp(x) = 0! + x**1/1! + x**2/2! + ... . 153 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b. 154 * For x close to zero, ln(1+x) =~ x, since 155 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1 156 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1). 157 * ln(.1) =~ -2.30 158 * 159 * Proof of (1): 160 * Solve (factor)**(power) =~ .1 given power (5*loadav): 161 * solving for factor, 162 * ln(factor) =~ (-2.30/5*loadav), or 163 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) = 164 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED 165 * 166 * Proof of (2): 167 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)): 168 * solving for power, 169 * power*ln(b/(b+1)) =~ -2.30, or 170 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED 171 * 172 * Actual power values for the implemented algorithm are as follows: 173 * loadav: 1 2 3 4 174 * power: 5.68 10.32 14.94 19.55 175 */ 176 177 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */ 178 #define loadfactor(loadav) (2 * (loadav)) 179 #define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE)) 180 181 /* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ 182 fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 183 184 /* 185 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 186 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 187 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 188 * 189 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 190 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 191 * 192 * If you don't want to bother with the faster/more-accurate formula, you 193 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 194 * (more general) method of calculating the %age of CPU used by a process. 195 */ 196 #define CCPU_SHIFT 11 197 198 /* 199 * Recompute process priorities, every second. 200 */ 201 void 202 schedcpu(void *arg) 203 { 204 struct timeout *to = (struct timeout *)arg; 205 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 206 struct proc *p; 207 int s; 208 unsigned int newcpu; 209 int phz; 210 211 /* 212 * If we have a statistics clock, use that to calculate CPU 213 * time, otherwise revert to using the profiling clock (which, 214 * in turn, defaults to hz if there is no separate profiling 215 * clock available) 216 */ 217 phz = stathz ? stathz : profhz; 218 KASSERT(phz); 219 220 LIST_FOREACH(p, &allproc, p_list) { 221 /* 222 * Idle threads are never placed on the runqueue, 223 * therefore computing their priority is pointless. 224 */ 225 if (p->p_cpu != NULL && 226 p->p_cpu->ci_schedstate.spc_idleproc == p) 227 continue; 228 /* 229 * Increment sleep time (if sleeping). We ignore overflow. 230 */ 231 if (p->p_stat == SSLEEP || p->p_stat == SSTOP) 232 p->p_slptime++; 233 p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT; 234 /* 235 * If the process has slept the entire second, 236 * stop recalculating its priority until it wakes up. 237 */ 238 if (p->p_slptime > 1) 239 continue; 240 SCHED_LOCK(s); 241 /* 242 * p_pctcpu is only for diagnostic tools such as ps. 243 */ 244 #if (FSHIFT >= CCPU_SHIFT) 245 p->p_pctcpu += (phz == 100)? 246 ((fixpt_t) p->p_cpticks) << (FSHIFT - CCPU_SHIFT): 247 100 * (((fixpt_t) p->p_cpticks) 248 << (FSHIFT - CCPU_SHIFT)) / phz; 249 #else 250 p->p_pctcpu += ((FSCALE - ccpu) * 251 (p->p_cpticks * FSCALE / phz)) >> FSHIFT; 252 #endif 253 p->p_cpticks = 0; 254 newcpu = (u_int) decay_cpu(loadfac, p->p_estcpu); 255 p->p_estcpu = newcpu; 256 resetpriority(p); 257 if (p->p_priority >= PUSER) { 258 if (p->p_stat == SRUN && 259 (p->p_priority / SCHED_PPQ) != 260 (p->p_usrpri / SCHED_PPQ)) { 261 remrunqueue(p); 262 p->p_priority = p->p_usrpri; 263 setrunqueue(p); 264 } else 265 p->p_priority = p->p_usrpri; 266 } 267 SCHED_UNLOCK(s); 268 } 269 uvm_meter(); 270 wakeup(&lbolt); 271 timeout_add_sec(to, 1); 272 } 273 274 /* 275 * Recalculate the priority of a process after it has slept for a while. 276 * For all load averages >= 1 and max p_estcpu of 255, sleeping for at 277 * least six times the loadfactor will decay p_estcpu to zero. 278 */ 279 void 280 updatepri(struct proc *p) 281 { 282 unsigned int newcpu = p->p_estcpu; 283 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 284 285 SCHED_ASSERT_LOCKED(); 286 287 if (p->p_slptime > 5 * loadfac) 288 p->p_estcpu = 0; 289 else { 290 p->p_slptime--; /* the first time was done in schedcpu */ 291 while (newcpu && --p->p_slptime) 292 newcpu = (int) decay_cpu(loadfac, newcpu); 293 p->p_estcpu = newcpu; 294 } 295 resetpriority(p); 296 } 297 298 /* 299 * General yield call. Puts the current process back on its run queue and 300 * performs a voluntary context switch. 301 */ 302 void 303 yield(void) 304 { 305 struct proc *p = curproc; 306 int s; 307 308 NET_ASSERT_UNLOCKED(); 309 310 SCHED_LOCK(s); 311 p->p_priority = p->p_usrpri; 312 p->p_stat = SRUN; 313 setrunqueue(p); 314 p->p_ru.ru_nvcsw++; 315 mi_switch(); 316 SCHED_UNLOCK(s); 317 } 318 319 /* 320 * General preemption call. Puts the current process back on its run queue 321 * and performs an involuntary context switch. If a process is supplied, 322 * we switch to that process. Otherwise, we use the normal process selection 323 * criteria. 324 */ 325 void 326 preempt(void) 327 { 328 struct proc *p = curproc; 329 int s; 330 331 SCHED_LOCK(s); 332 p->p_priority = p->p_usrpri; 333 p->p_stat = SRUN; 334 setrunqueue(p); 335 p->p_ru.ru_nivcsw++; 336 mi_switch(); 337 SCHED_UNLOCK(s); 338 } 339 340 void 341 mi_switch(void) 342 { 343 struct schedstate_percpu *spc = &curcpu()->ci_schedstate; 344 struct proc *p = curproc; 345 struct proc *nextproc; 346 struct process *pr = p->p_p; 347 struct timespec ts; 348 #ifdef MULTIPROCESSOR 349 int hold_count; 350 int sched_count; 351 #endif 352 353 assertwaitok(); 354 KASSERT(p->p_stat != SONPROC); 355 356 SCHED_ASSERT_LOCKED(); 357 358 #ifdef MULTIPROCESSOR 359 /* 360 * Release the kernel_lock, as we are about to yield the CPU. 361 */ 362 sched_count = __mp_release_all_but_one(&sched_lock); 363 if (_kernel_lock_held()) 364 hold_count = __mp_release_all(&kernel_lock); 365 else 366 hold_count = 0; 367 #endif 368 369 /* 370 * Compute the amount of time during which the current 371 * process was running, and add that to its total so far. 372 */ 373 nanouptime(&ts); 374 if (timespeccmp(&ts, &spc->spc_runtime, <)) { 375 #if 0 376 printf("uptime is not monotonic! " 377 "ts=%lld.%09lu, runtime=%lld.%09lu\n", 378 (long long)tv.tv_sec, tv.tv_nsec, 379 (long long)spc->spc_runtime.tv_sec, 380 spc->spc_runtime.tv_nsec); 381 #endif 382 } else { 383 timespecsub(&ts, &spc->spc_runtime, &ts); 384 timespecadd(&p->p_rtime, &ts, &p->p_rtime); 385 } 386 387 /* add the time counts for this thread to the process's total */ 388 tuagg_unlocked(pr, p); 389 390 /* 391 * Process is about to yield the CPU; clear the appropriate 392 * scheduling flags. 393 */ 394 atomic_clearbits_int(&spc->spc_schedflags, SPCF_SWITCHCLEAR); 395 396 nextproc = sched_chooseproc(); 397 398 if (p != nextproc) { 399 uvmexp.swtch++; 400 cpu_switchto(p, nextproc); 401 } else { 402 p->p_stat = SONPROC; 403 } 404 405 clear_resched(curcpu()); 406 407 SCHED_ASSERT_LOCKED(); 408 409 /* 410 * To preserve lock ordering, we need to release the sched lock 411 * and grab it after we grab the big lock. 412 * In the future, when the sched lock isn't recursive, we'll 413 * just release it here. 414 */ 415 #ifdef MULTIPROCESSOR 416 __mp_unlock(&sched_lock); 417 #endif 418 419 SCHED_ASSERT_UNLOCKED(); 420 421 smr_idle(); 422 423 /* 424 * We're running again; record our new start time. We might 425 * be running on a new CPU now, so don't use the cache'd 426 * schedstate_percpu pointer. 427 */ 428 KASSERT(p->p_cpu == curcpu()); 429 430 nanouptime(&p->p_cpu->ci_schedstate.spc_runtime); 431 432 #ifdef MULTIPROCESSOR 433 /* 434 * Reacquire the kernel_lock now. We do this after we've 435 * released the scheduler lock to avoid deadlock, and before 436 * we reacquire the interlock and the scheduler lock. 437 */ 438 if (hold_count) 439 __mp_acquire_count(&kernel_lock, hold_count); 440 __mp_acquire_count(&sched_lock, sched_count + 1); 441 #endif 442 } 443 444 static __inline void 445 resched_proc(struct proc *p, u_char pri) 446 { 447 struct cpu_info *ci; 448 449 /* 450 * XXXSMP 451 * This does not handle the case where its last 452 * CPU is running a higher-priority process, but every 453 * other CPU is running a lower-priority process. There 454 * are ways to handle this situation, but they're not 455 * currently very pretty, and we also need to weigh the 456 * cost of moving a process from one CPU to another. 457 * 458 * XXXSMP 459 * There is also the issue of locking the other CPU's 460 * sched state, which we currently do not do. 461 */ 462 ci = (p->p_cpu != NULL) ? p->p_cpu : curcpu(); 463 if (pri < ci->ci_schedstate.spc_curpriority) 464 need_resched(ci); 465 } 466 467 /* 468 * Change process state to be runnable, 469 * placing it on the run queue if it is in memory, 470 * and awakening the swapper if it isn't in memory. 471 */ 472 void 473 setrunnable(struct proc *p) 474 { 475 SCHED_ASSERT_LOCKED(); 476 477 switch (p->p_stat) { 478 case 0: 479 case SRUN: 480 case SONPROC: 481 case SDEAD: 482 case SIDL: 483 default: 484 panic("setrunnable"); 485 case SSTOP: 486 /* 487 * If we're being traced (possibly because someone attached us 488 * while we were stopped), check for a signal from the debugger. 489 */ 490 if ((p->p_p->ps_flags & PS_TRACED) != 0 && p->p_xstat != 0) 491 atomic_setbits_int(&p->p_siglist, sigmask(p->p_xstat)); 492 case SSLEEP: 493 unsleep(p); /* e.g. when sending signals */ 494 break; 495 } 496 p->p_stat = SRUN; 497 p->p_cpu = sched_choosecpu(p); 498 setrunqueue(p); 499 if (p->p_slptime > 1) 500 updatepri(p); 501 p->p_slptime = 0; 502 resched_proc(p, p->p_priority); 503 } 504 505 /* 506 * Compute the priority of a process when running in user mode. 507 * Arrange to reschedule if the resulting priority is better 508 * than that of the current process. 509 */ 510 void 511 resetpriority(struct proc *p) 512 { 513 unsigned int newpriority; 514 515 SCHED_ASSERT_LOCKED(); 516 517 newpriority = PUSER + p->p_estcpu + 518 NICE_WEIGHT * (p->p_p->ps_nice - NZERO); 519 newpriority = min(newpriority, MAXPRI); 520 p->p_usrpri = newpriority; 521 resched_proc(p, p->p_usrpri); 522 } 523 524 /* 525 * We adjust the priority of the current process. The priority of a process 526 * gets worse as it accumulates CPU time. The cpu usage estimator (p_estcpu) 527 * is increased here. The formula for computing priorities (in kern_synch.c) 528 * will compute a different value each time p_estcpu increases. This can 529 * cause a switch, but unless the priority crosses a PPQ boundary the actual 530 * queue will not change. The cpu usage estimator ramps up quite quickly 531 * when the process is running (linearly), and decays away exponentially, at 532 * a rate which is proportionally slower when the system is busy. The basic 533 * principle is that the system will 90% forget that the process used a lot 534 * of CPU time in 5 * loadav seconds. This causes the system to favor 535 * processes which haven't run much recently, and to round-robin among other 536 * processes. 537 */ 538 void 539 schedclock(struct proc *p) 540 { 541 struct cpu_info *ci = curcpu(); 542 struct schedstate_percpu *spc = &ci->ci_schedstate; 543 int s; 544 545 if (p == spc->spc_idleproc) 546 return; 547 548 SCHED_LOCK(s); 549 p->p_estcpu = ESTCPULIM(p->p_estcpu + 1); 550 resetpriority(p); 551 if (p->p_priority >= PUSER) 552 p->p_priority = p->p_usrpri; 553 SCHED_UNLOCK(s); 554 } 555 556 void (*cpu_setperf)(int); 557 558 #define PERFPOL_MANUAL 0 559 #define PERFPOL_AUTO 1 560 #define PERFPOL_HIGH 2 561 int perflevel = 100; 562 int perfpolicy = PERFPOL_MANUAL; 563 564 #ifndef SMALL_KERNEL 565 /* 566 * The code below handles CPU throttling. 567 */ 568 #include <sys/sysctl.h> 569 570 void setperf_auto(void *); 571 struct timeout setperf_to = TIMEOUT_INITIALIZER(setperf_auto, NULL); 572 573 void 574 setperf_auto(void *v) 575 { 576 static uint64_t *idleticks, *totalticks; 577 static int downbeats; 578 579 int i, j; 580 int speedup; 581 CPU_INFO_ITERATOR cii; 582 struct cpu_info *ci; 583 uint64_t idle, total, allidle, alltotal; 584 585 if (perfpolicy != PERFPOL_AUTO) 586 return; 587 588 if (!idleticks) 589 if (!(idleticks = mallocarray(ncpusfound, sizeof(*idleticks), 590 M_DEVBUF, M_NOWAIT | M_ZERO))) 591 return; 592 if (!totalticks) 593 if (!(totalticks = mallocarray(ncpusfound, sizeof(*totalticks), 594 M_DEVBUF, M_NOWAIT | M_ZERO))) { 595 free(idleticks, M_DEVBUF, 596 sizeof(*idleticks) * ncpusfound); 597 return; 598 } 599 600 alltotal = allidle = 0; 601 j = 0; 602 speedup = 0; 603 CPU_INFO_FOREACH(cii, ci) { 604 total = 0; 605 for (i = 0; i < CPUSTATES; i++) { 606 total += ci->ci_schedstate.spc_cp_time[i]; 607 } 608 total -= totalticks[j]; 609 idle = ci->ci_schedstate.spc_cp_time[CP_IDLE] - idleticks[j]; 610 if (idle < total / 3) 611 speedup = 1; 612 alltotal += total; 613 allidle += idle; 614 idleticks[j] += idle; 615 totalticks[j] += total; 616 j++; 617 } 618 if (allidle < alltotal / 2) 619 speedup = 1; 620 if (speedup) 621 downbeats = 5; 622 623 if (speedup && perflevel != 100) { 624 perflevel = 100; 625 cpu_setperf(perflevel); 626 } else if (!speedup && perflevel != 0 && --downbeats <= 0) { 627 perflevel = 0; 628 cpu_setperf(perflevel); 629 } 630 631 timeout_add_msec(&setperf_to, 100); 632 } 633 634 int 635 sysctl_hwsetperf(void *oldp, size_t *oldlenp, void *newp, size_t newlen) 636 { 637 int err, newperf; 638 639 if (!cpu_setperf) 640 return EOPNOTSUPP; 641 642 if (perfpolicy != PERFPOL_MANUAL) 643 return sysctl_rdint(oldp, oldlenp, newp, perflevel); 644 645 newperf = perflevel; 646 err = sysctl_int(oldp, oldlenp, newp, newlen, &newperf); 647 if (err) 648 return err; 649 if (newperf > 100) 650 newperf = 100; 651 if (newperf < 0) 652 newperf = 0; 653 perflevel = newperf; 654 cpu_setperf(perflevel); 655 656 return 0; 657 } 658 659 int 660 sysctl_hwperfpolicy(void *oldp, size_t *oldlenp, void *newp, size_t newlen) 661 { 662 char policy[32]; 663 int err; 664 665 if (!cpu_setperf) 666 return EOPNOTSUPP; 667 668 switch (perfpolicy) { 669 case PERFPOL_MANUAL: 670 strlcpy(policy, "manual", sizeof(policy)); 671 break; 672 case PERFPOL_AUTO: 673 strlcpy(policy, "auto", sizeof(policy)); 674 break; 675 case PERFPOL_HIGH: 676 strlcpy(policy, "high", sizeof(policy)); 677 break; 678 default: 679 strlcpy(policy, "unknown", sizeof(policy)); 680 break; 681 } 682 683 if (newp == NULL) 684 return sysctl_rdstring(oldp, oldlenp, newp, policy); 685 686 err = sysctl_string(oldp, oldlenp, newp, newlen, policy, sizeof(policy)); 687 if (err) 688 return err; 689 if (strcmp(policy, "manual") == 0) 690 perfpolicy = PERFPOL_MANUAL; 691 else if (strcmp(policy, "auto") == 0) 692 perfpolicy = PERFPOL_AUTO; 693 else if (strcmp(policy, "high") == 0) 694 perfpolicy = PERFPOL_HIGH; 695 else 696 return EINVAL; 697 698 if (perfpolicy == PERFPOL_AUTO) { 699 timeout_add_msec(&setperf_to, 200); 700 } else if (perfpolicy == PERFPOL_HIGH) { 701 perflevel = 100; 702 cpu_setperf(perflevel); 703 } 704 return 0; 705 } 706 #endif 707