1 /* $OpenBSD: sched_bsd.c,v 1.47 2017/12/04 09:38:20 mpi 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 51 #ifdef KTRACE 52 #include <sys/ktrace.h> 53 #endif 54 55 56 int lbolt; /* once a second sleep address */ 57 int rrticks_init; /* # of hardclock ticks per roundrobin() */ 58 59 #ifdef MULTIPROCESSOR 60 struct __mp_lock sched_lock; 61 #endif 62 63 void schedcpu(void *); 64 void updatepri(struct proc *); 65 66 void 67 scheduler_start(void) 68 { 69 static struct timeout schedcpu_to; 70 71 /* 72 * We avoid polluting the global namespace by keeping the scheduler 73 * timeouts static in this function. 74 * We setup the timeout here and kick schedcpu once to make it do 75 * its job. 76 */ 77 timeout_set(&schedcpu_to, schedcpu, &schedcpu_to); 78 79 rrticks_init = hz / 10; 80 schedcpu(&schedcpu_to); 81 } 82 83 /* 84 * Force switch among equal priority processes every 100ms. 85 */ 86 void 87 roundrobin(struct cpu_info *ci) 88 { 89 struct schedstate_percpu *spc = &ci->ci_schedstate; 90 91 spc->spc_rrticks = rrticks_init; 92 93 if (ci->ci_curproc != NULL) { 94 if (spc->spc_schedflags & SPCF_SEENRR) { 95 /* 96 * The process has already been through a roundrobin 97 * without switching and may be hogging the CPU. 98 * Indicate that the process should yield. 99 */ 100 atomic_setbits_int(&spc->spc_schedflags, 101 SPCF_SHOULDYIELD); 102 } else { 103 atomic_setbits_int(&spc->spc_schedflags, 104 SPCF_SEENRR); 105 } 106 } 107 108 if (spc->spc_nrun) 109 need_resched(ci); 110 } 111 112 /* 113 * Constants for digital decay and forget: 114 * 90% of (p_estcpu) usage in 5 * loadav time 115 * 95% of (p_pctcpu) usage in 60 seconds (load insensitive) 116 * Note that, as ps(1) mentions, this can let percentages 117 * total over 100% (I've seen 137.9% for 3 processes). 118 * 119 * Note that hardclock updates p_estcpu and p_cpticks independently. 120 * 121 * We wish to decay away 90% of p_estcpu in (5 * loadavg) seconds. 122 * That is, the system wants to compute a value of decay such 123 * that the following for loop: 124 * for (i = 0; i < (5 * loadavg); i++) 125 * p_estcpu *= decay; 126 * will compute 127 * p_estcpu *= 0.1; 128 * for all values of loadavg: 129 * 130 * Mathematically this loop can be expressed by saying: 131 * decay ** (5 * loadavg) ~= .1 132 * 133 * The system computes decay as: 134 * decay = (2 * loadavg) / (2 * loadavg + 1) 135 * 136 * We wish to prove that the system's computation of decay 137 * will always fulfill the equation: 138 * decay ** (5 * loadavg) ~= .1 139 * 140 * If we compute b as: 141 * b = 2 * loadavg 142 * then 143 * decay = b / (b + 1) 144 * 145 * We now need to prove two things: 146 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1) 147 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg) 148 * 149 * Facts: 150 * For x close to zero, exp(x) =~ 1 + x, since 151 * exp(x) = 0! + x**1/1! + x**2/2! + ... . 152 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b. 153 * For x close to zero, ln(1+x) =~ x, since 154 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1 155 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1). 156 * ln(.1) =~ -2.30 157 * 158 * Proof of (1): 159 * Solve (factor)**(power) =~ .1 given power (5*loadav): 160 * solving for factor, 161 * ln(factor) =~ (-2.30/5*loadav), or 162 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) = 163 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED 164 * 165 * Proof of (2): 166 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)): 167 * solving for power, 168 * power*ln(b/(b+1)) =~ -2.30, or 169 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED 170 * 171 * Actual power values for the implemented algorithm are as follows: 172 * loadav: 1 2 3 4 173 * power: 5.68 10.32 14.94 19.55 174 */ 175 176 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */ 177 #define loadfactor(loadav) (2 * (loadav)) 178 #define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE)) 179 180 /* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ 181 fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 182 183 /* 184 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 185 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 186 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 187 * 188 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 189 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 190 * 191 * If you don't want to bother with the faster/more-accurate formula, you 192 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 193 * (more general) method of calculating the %age of CPU used by a process. 194 */ 195 #define CCPU_SHIFT 11 196 197 /* 198 * Recompute process priorities, every second. 199 */ 200 void 201 schedcpu(void *arg) 202 { 203 struct timeout *to = (struct timeout *)arg; 204 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 205 struct proc *p; 206 int s; 207 unsigned int newcpu; 208 int phz; 209 210 /* 211 * If we have a statistics clock, use that to calculate CPU 212 * time, otherwise revert to using the profiling clock (which, 213 * in turn, defaults to hz if there is no separate profiling 214 * clock available) 215 */ 216 phz = stathz ? stathz : profhz; 217 KASSERT(phz); 218 219 LIST_FOREACH(p, &allproc, p_list) { 220 /* 221 * Increment sleep time (if sleeping). We ignore overflow. 222 */ 223 if (p->p_stat == SSLEEP || p->p_stat == SSTOP) 224 p->p_slptime++; 225 p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT; 226 /* 227 * If the process has slept the entire second, 228 * stop recalculating its priority until it wakes up. 229 */ 230 if (p->p_slptime > 1) 231 continue; 232 SCHED_LOCK(s); 233 /* 234 * p_pctcpu is only for diagnostic tools such as ps. 235 */ 236 #if (FSHIFT >= CCPU_SHIFT) 237 p->p_pctcpu += (phz == 100)? 238 ((fixpt_t) p->p_cpticks) << (FSHIFT - CCPU_SHIFT): 239 100 * (((fixpt_t) p->p_cpticks) 240 << (FSHIFT - CCPU_SHIFT)) / phz; 241 #else 242 p->p_pctcpu += ((FSCALE - ccpu) * 243 (p->p_cpticks * FSCALE / phz)) >> FSHIFT; 244 #endif 245 p->p_cpticks = 0; 246 newcpu = (u_int) decay_cpu(loadfac, p->p_estcpu); 247 p->p_estcpu = newcpu; 248 resetpriority(p); 249 if (p->p_priority >= PUSER) { 250 if (p->p_stat == SRUN && 251 (p->p_priority / SCHED_PPQ) != 252 (p->p_usrpri / SCHED_PPQ)) { 253 remrunqueue(p); 254 p->p_priority = p->p_usrpri; 255 setrunqueue(p); 256 } else 257 p->p_priority = p->p_usrpri; 258 } 259 SCHED_UNLOCK(s); 260 } 261 uvm_meter(); 262 wakeup(&lbolt); 263 timeout_add_sec(to, 1); 264 } 265 266 /* 267 * Recalculate the priority of a process after it has slept for a while. 268 * For all load averages >= 1 and max p_estcpu of 255, sleeping for at 269 * least six times the loadfactor will decay p_estcpu to zero. 270 */ 271 void 272 updatepri(struct proc *p) 273 { 274 unsigned int newcpu = p->p_estcpu; 275 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 276 277 SCHED_ASSERT_LOCKED(); 278 279 if (p->p_slptime > 5 * loadfac) 280 p->p_estcpu = 0; 281 else { 282 p->p_slptime--; /* the first time was done in schedcpu */ 283 while (newcpu && --p->p_slptime) 284 newcpu = (int) decay_cpu(loadfac, newcpu); 285 p->p_estcpu = newcpu; 286 } 287 resetpriority(p); 288 } 289 290 /* 291 * General yield call. Puts the current process back on its run queue and 292 * performs a voluntary context switch. 293 */ 294 void 295 yield(void) 296 { 297 struct proc *p = curproc; 298 int s; 299 300 NET_ASSERT_UNLOCKED(); 301 302 SCHED_LOCK(s); 303 p->p_priority = p->p_usrpri; 304 p->p_stat = SRUN; 305 setrunqueue(p); 306 p->p_ru.ru_nvcsw++; 307 mi_switch(); 308 SCHED_UNLOCK(s); 309 } 310 311 /* 312 * General preemption call. Puts the current process back on its run queue 313 * and performs an involuntary context switch. If a process is supplied, 314 * we switch to that process. Otherwise, we use the normal process selection 315 * criteria. 316 */ 317 void 318 preempt(void) 319 { 320 struct proc *p = curproc; 321 int s; 322 323 SCHED_LOCK(s); 324 p->p_priority = p->p_usrpri; 325 p->p_stat = SRUN; 326 setrunqueue(p); 327 p->p_ru.ru_nivcsw++; 328 mi_switch(); 329 SCHED_UNLOCK(s); 330 } 331 332 void 333 mi_switch(void) 334 { 335 struct schedstate_percpu *spc = &curcpu()->ci_schedstate; 336 struct proc *p = curproc; 337 struct proc *nextproc; 338 struct process *pr = p->p_p; 339 struct rlimit *rlim; 340 rlim_t secs; 341 struct timespec ts; 342 #ifdef MULTIPROCESSOR 343 int hold_count; 344 int sched_count; 345 #endif 346 347 assertwaitok(); 348 KASSERT(p->p_stat != SONPROC); 349 350 SCHED_ASSERT_LOCKED(); 351 352 #ifdef MULTIPROCESSOR 353 /* 354 * Release the kernel_lock, as we are about to yield the CPU. 355 */ 356 sched_count = __mp_release_all_but_one(&sched_lock); 357 if (_kernel_lock_held()) 358 hold_count = __mp_release_all(&kernel_lock); 359 else 360 hold_count = 0; 361 #endif 362 363 /* 364 * Compute the amount of time during which the current 365 * process was running, and add that to its total so far. 366 */ 367 nanouptime(&ts); 368 if (timespeccmp(&ts, &spc->spc_runtime, <)) { 369 #if 0 370 printf("uptime is not monotonic! " 371 "ts=%lld.%09lu, runtime=%lld.%09lu\n", 372 (long long)tv.tv_sec, tv.tv_nsec, 373 (long long)spc->spc_runtime.tv_sec, 374 spc->spc_runtime.tv_nsec); 375 #endif 376 } else { 377 timespecsub(&ts, &spc->spc_runtime, &ts); 378 timespecadd(&p->p_rtime, &ts, &p->p_rtime); 379 } 380 381 /* add the time counts for this thread to the process's total */ 382 tuagg_unlocked(pr, p); 383 384 /* 385 * Check if the process exceeds its cpu resource allocation. 386 * If over max, kill it. 387 */ 388 rlim = &pr->ps_limit->pl_rlimit[RLIMIT_CPU]; 389 secs = pr->ps_tu.tu_runtime.tv_sec; 390 if (secs >= rlim->rlim_cur) { 391 if (secs >= rlim->rlim_max) { 392 psignal(p, SIGKILL); 393 } else { 394 psignal(p, SIGXCPU); 395 if (rlim->rlim_cur < rlim->rlim_max) 396 rlim->rlim_cur += 5; 397 } 398 } 399 400 /* 401 * Process is about to yield the CPU; clear the appropriate 402 * scheduling flags. 403 */ 404 atomic_clearbits_int(&spc->spc_schedflags, SPCF_SWITCHCLEAR); 405 406 nextproc = sched_chooseproc(); 407 408 if (p != nextproc) { 409 uvmexp.swtch++; 410 cpu_switchto(p, nextproc); 411 } else { 412 p->p_stat = SONPROC; 413 } 414 415 clear_resched(curcpu()); 416 417 SCHED_ASSERT_LOCKED(); 418 419 /* 420 * To preserve lock ordering, we need to release the sched lock 421 * and grab it after we grab the big lock. 422 * In the future, when the sched lock isn't recursive, we'll 423 * just release it here. 424 */ 425 #ifdef MULTIPROCESSOR 426 __mp_unlock(&sched_lock); 427 #endif 428 429 SCHED_ASSERT_UNLOCKED(); 430 431 /* 432 * We're running again; record our new start time. We might 433 * be running on a new CPU now, so don't use the cache'd 434 * schedstate_percpu pointer. 435 */ 436 KASSERT(p->p_cpu == curcpu()); 437 438 nanouptime(&p->p_cpu->ci_schedstate.spc_runtime); 439 440 #ifdef MULTIPROCESSOR 441 /* 442 * Reacquire the kernel_lock now. We do this after we've 443 * released the scheduler lock to avoid deadlock, and before 444 * we reacquire the interlock and the scheduler lock. 445 */ 446 if (hold_count) 447 __mp_acquire_count(&kernel_lock, hold_count); 448 __mp_acquire_count(&sched_lock, sched_count + 1); 449 #endif 450 } 451 452 static __inline void 453 resched_proc(struct proc *p, u_char pri) 454 { 455 struct cpu_info *ci; 456 457 /* 458 * XXXSMP 459 * This does not handle the case where its last 460 * CPU is running a higher-priority process, but every 461 * other CPU is running a lower-priority process. There 462 * are ways to handle this situation, but they're not 463 * currently very pretty, and we also need to weigh the 464 * cost of moving a process from one CPU to another. 465 * 466 * XXXSMP 467 * There is also the issue of locking the other CPU's 468 * sched state, which we currently do not do. 469 */ 470 ci = (p->p_cpu != NULL) ? p->p_cpu : curcpu(); 471 if (pri < ci->ci_schedstate.spc_curpriority) 472 need_resched(ci); 473 } 474 475 /* 476 * Change process state to be runnable, 477 * placing it on the run queue if it is in memory, 478 * and awakening the swapper if it isn't in memory. 479 */ 480 void 481 setrunnable(struct proc *p) 482 { 483 SCHED_ASSERT_LOCKED(); 484 485 switch (p->p_stat) { 486 case 0: 487 case SRUN: 488 case SONPROC: 489 case SDEAD: 490 case SIDL: 491 default: 492 panic("setrunnable"); 493 case SSTOP: 494 /* 495 * If we're being traced (possibly because someone attached us 496 * while we were stopped), check for a signal from the debugger. 497 */ 498 if ((p->p_p->ps_flags & PS_TRACED) != 0 && p->p_xstat != 0) 499 atomic_setbits_int(&p->p_siglist, sigmask(p->p_xstat)); 500 case SSLEEP: 501 unsleep(p); /* e.g. when sending signals */ 502 break; 503 } 504 p->p_stat = SRUN; 505 p->p_cpu = sched_choosecpu(p); 506 setrunqueue(p); 507 if (p->p_slptime > 1) 508 updatepri(p); 509 p->p_slptime = 0; 510 resched_proc(p, p->p_priority); 511 } 512 513 /* 514 * Compute the priority of a process when running in user mode. 515 * Arrange to reschedule if the resulting priority is better 516 * than that of the current process. 517 */ 518 void 519 resetpriority(struct proc *p) 520 { 521 unsigned int newpriority; 522 523 SCHED_ASSERT_LOCKED(); 524 525 newpriority = PUSER + p->p_estcpu + 526 NICE_WEIGHT * (p->p_p->ps_nice - NZERO); 527 newpriority = min(newpriority, MAXPRI); 528 p->p_usrpri = newpriority; 529 resched_proc(p, p->p_usrpri); 530 } 531 532 /* 533 * We adjust the priority of the current process. The priority of a process 534 * gets worse as it accumulates CPU time. The cpu usage estimator (p_estcpu) 535 * is increased here. The formula for computing priorities (in kern_synch.c) 536 * will compute a different value each time p_estcpu increases. This can 537 * cause a switch, but unless the priority crosses a PPQ boundary the actual 538 * queue will not change. The cpu usage estimator ramps up quite quickly 539 * when the process is running (linearly), and decays away exponentially, at 540 * a rate which is proportionally slower when the system is busy. The basic 541 * principle is that the system will 90% forget that the process used a lot 542 * of CPU time in 5 * loadav seconds. This causes the system to favor 543 * processes which haven't run much recently, and to round-robin among other 544 * processes. 545 */ 546 void 547 schedclock(struct proc *p) 548 { 549 int s; 550 551 SCHED_LOCK(s); 552 p->p_estcpu = ESTCPULIM(p->p_estcpu + 1); 553 resetpriority(p); 554 if (p->p_priority >= PUSER) 555 p->p_priority = p->p_usrpri; 556 SCHED_UNLOCK(s); 557 } 558 559 void (*cpu_setperf)(int); 560 561 #define PERFPOL_MANUAL 0 562 #define PERFPOL_AUTO 1 563 #define PERFPOL_HIGH 2 564 int perflevel = 100; 565 int perfpolicy = PERFPOL_MANUAL; 566 567 #ifndef SMALL_KERNEL 568 /* 569 * The code below handles CPU throttling. 570 */ 571 #include <sys/sysctl.h> 572 573 void setperf_auto(void *); 574 struct timeout setperf_to = TIMEOUT_INITIALIZER(setperf_auto, NULL); 575 576 void 577 setperf_auto(void *v) 578 { 579 static uint64_t *idleticks, *totalticks; 580 static int downbeats; 581 582 int i, j; 583 int speedup; 584 CPU_INFO_ITERATOR cii; 585 struct cpu_info *ci; 586 uint64_t idle, total, allidle, alltotal; 587 588 if (perfpolicy != PERFPOL_AUTO) 589 return; 590 591 if (!idleticks) 592 if (!(idleticks = mallocarray(ncpusfound, sizeof(*idleticks), 593 M_DEVBUF, M_NOWAIT | M_ZERO))) 594 return; 595 if (!totalticks) 596 if (!(totalticks = mallocarray(ncpusfound, sizeof(*totalticks), 597 M_DEVBUF, M_NOWAIT | M_ZERO))) { 598 free(idleticks, M_DEVBUF, 599 sizeof(*idleticks) * ncpusfound); 600 return; 601 } 602 603 alltotal = allidle = 0; 604 j = 0; 605 speedup = 0; 606 CPU_INFO_FOREACH(cii, ci) { 607 total = 0; 608 for (i = 0; i < CPUSTATES; i++) { 609 total += ci->ci_schedstate.spc_cp_time[i]; 610 } 611 total -= totalticks[j]; 612 idle = ci->ci_schedstate.spc_cp_time[CP_IDLE] - idleticks[j]; 613 if (idle < total / 3) 614 speedup = 1; 615 alltotal += total; 616 allidle += idle; 617 idleticks[j] += idle; 618 totalticks[j] += total; 619 j++; 620 } 621 if (allidle < alltotal / 2) 622 speedup = 1; 623 if (speedup) 624 downbeats = 5; 625 626 if (speedup && perflevel != 100) { 627 perflevel = 100; 628 cpu_setperf(perflevel); 629 } else if (!speedup && perflevel != 0 && --downbeats <= 0) { 630 perflevel = 0; 631 cpu_setperf(perflevel); 632 } 633 634 timeout_add_msec(&setperf_to, 100); 635 } 636 637 int 638 sysctl_hwsetperf(void *oldp, size_t *oldlenp, void *newp, size_t newlen) 639 { 640 int err, newperf; 641 642 if (!cpu_setperf) 643 return EOPNOTSUPP; 644 645 if (perfpolicy != PERFPOL_MANUAL) 646 return sysctl_rdint(oldp, oldlenp, newp, perflevel); 647 648 newperf = perflevel; 649 err = sysctl_int(oldp, oldlenp, newp, newlen, &newperf); 650 if (err) 651 return err; 652 if (newperf > 100) 653 newperf = 100; 654 if (newperf < 0) 655 newperf = 0; 656 perflevel = newperf; 657 cpu_setperf(perflevel); 658 659 return 0; 660 } 661 662 int 663 sysctl_hwperfpolicy(void *oldp, size_t *oldlenp, void *newp, size_t newlen) 664 { 665 char policy[32]; 666 int err; 667 668 if (!cpu_setperf) 669 return EOPNOTSUPP; 670 671 switch (perfpolicy) { 672 case PERFPOL_MANUAL: 673 strlcpy(policy, "manual", sizeof(policy)); 674 break; 675 case PERFPOL_AUTO: 676 strlcpy(policy, "auto", sizeof(policy)); 677 break; 678 case PERFPOL_HIGH: 679 strlcpy(policy, "high", sizeof(policy)); 680 break; 681 default: 682 strlcpy(policy, "unknown", sizeof(policy)); 683 break; 684 } 685 686 if (newp == NULL) 687 return sysctl_rdstring(oldp, oldlenp, newp, policy); 688 689 err = sysctl_string(oldp, oldlenp, newp, newlen, policy, sizeof(policy)); 690 if (err) 691 return err; 692 if (strcmp(policy, "manual") == 0) 693 perfpolicy = PERFPOL_MANUAL; 694 else if (strcmp(policy, "auto") == 0) 695 perfpolicy = PERFPOL_AUTO; 696 else if (strcmp(policy, "high") == 0) 697 perfpolicy = PERFPOL_HIGH; 698 else 699 return EINVAL; 700 701 if (perfpolicy == PERFPOL_AUTO) { 702 timeout_add_msec(&setperf_to, 200); 703 } else if (perfpolicy == PERFPOL_HIGH) { 704 perflevel = 100; 705 cpu_setperf(perflevel); 706 } 707 return 0; 708 } 709 #endif 710