| 1 | /* $NetBSD: sched_4bsd.c,v 1.30 2014/06/24 10:08:45 maxv Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 1999, 2000, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, |
| 9 | * NASA Ames Research Center, by Charles M. Hannum, Andrew Doran, and |
| 10 | * Daniel Sieger. |
| 11 | * |
| 12 | * Redistribution and use in source and binary forms, with or without |
| 13 | * modification, are permitted provided that the following conditions |
| 14 | * are met: |
| 15 | * 1. Redistributions of source code must retain the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer. |
| 17 | * 2. Redistributions in binary form must reproduce the above copyright |
| 18 | * notice, this list of conditions and the following disclaimer in the |
| 19 | * documentation and/or other materials provided with the distribution. |
| 20 | * |
| 21 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 22 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 23 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 24 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 25 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 26 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 27 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 28 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 29 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 30 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 31 | * POSSIBILITY OF SUCH DAMAGE. |
| 32 | */ |
| 33 | |
| 34 | /*- |
| 35 | * Copyright (c) 1982, 1986, 1990, 1991, 1993 |
| 36 | * The Regents of the University of California. All rights reserved. |
| 37 | * (c) UNIX System Laboratories, Inc. |
| 38 | * All or some portions of this file are derived from material licensed |
| 39 | * to the University of California by American Telephone and Telegraph |
| 40 | * Co. or Unix System Laboratories, Inc. and are reproduced herein with |
| 41 | * the permission of UNIX System Laboratories, Inc. |
| 42 | * |
| 43 | * Redistribution and use in source and binary forms, with or without |
| 44 | * modification, are permitted provided that the following conditions |
| 45 | * are met: |
| 46 | * 1. Redistributions of source code must retain the above copyright |
| 47 | * notice, this list of conditions and the following disclaimer. |
| 48 | * 2. Redistributions in binary form must reproduce the above copyright |
| 49 | * notice, this list of conditions and the following disclaimer in the |
| 50 | * documentation and/or other materials provided with the distribution. |
| 51 | * 3. Neither the name of the University nor the names of its contributors |
| 52 | * may be used to endorse or promote products derived from this software |
| 53 | * without specific prior written permission. |
| 54 | * |
| 55 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 56 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 57 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 58 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 59 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 60 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 61 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 62 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 63 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 64 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 65 | * SUCH DAMAGE. |
| 66 | * |
| 67 | * @(#)kern_synch.c 8.9 (Berkeley) 5/19/95 |
| 68 | */ |
| 69 | |
| 70 | #include <sys/cdefs.h> |
| 71 | __KERNEL_RCSID(0, "$NetBSD: sched_4bsd.c,v 1.30 2014/06/24 10:08:45 maxv Exp $" ); |
| 72 | |
| 73 | #include "opt_ddb.h" |
| 74 | #include "opt_lockdebug.h" |
| 75 | #include "opt_perfctrs.h" |
| 76 | |
| 77 | #include <sys/param.h> |
| 78 | #include <sys/systm.h> |
| 79 | #include <sys/callout.h> |
| 80 | #include <sys/cpu.h> |
| 81 | #include <sys/proc.h> |
| 82 | #include <sys/kernel.h> |
| 83 | #include <sys/signalvar.h> |
| 84 | #include <sys/resourcevar.h> |
| 85 | #include <sys/sched.h> |
| 86 | #include <sys/sysctl.h> |
| 87 | #include <sys/kauth.h> |
| 88 | #include <sys/lockdebug.h> |
| 89 | #include <sys/kmem.h> |
| 90 | #include <sys/intr.h> |
| 91 | |
| 92 | static void updatepri(struct lwp *); |
| 93 | static void resetpriority(struct lwp *); |
| 94 | |
| 95 | extern unsigned int sched_pstats_ticks; /* defined in kern_synch.c */ |
| 96 | |
| 97 | /* Number of hardclock ticks per sched_tick() */ |
| 98 | static int rrticks; |
| 99 | |
| 100 | /* |
| 101 | * Force switch among equal priority processes every 100ms. |
| 102 | * Called from hardclock every hz/10 == rrticks hardclock ticks. |
| 103 | * |
| 104 | * There's no need to lock anywhere in this routine, as it's |
| 105 | * CPU-local and runs at IPL_SCHED (called from clock interrupt). |
| 106 | */ |
| 107 | /* ARGSUSED */ |
| 108 | void |
| 109 | sched_tick(struct cpu_info *ci) |
| 110 | { |
| 111 | struct schedstate_percpu *spc = &ci->ci_schedstate; |
| 112 | lwp_t *l; |
| 113 | |
| 114 | spc->spc_ticks = rrticks; |
| 115 | |
| 116 | if (CURCPU_IDLE_P()) { |
| 117 | cpu_need_resched(ci, 0); |
| 118 | return; |
| 119 | } |
| 120 | l = ci->ci_data.cpu_onproc; |
| 121 | if (l == NULL) { |
| 122 | return; |
| 123 | } |
| 124 | switch (l->l_class) { |
| 125 | case SCHED_FIFO: |
| 126 | /* No timeslicing for FIFO jobs. */ |
| 127 | break; |
| 128 | case SCHED_RR: |
| 129 | /* Force it into mi_switch() to look for other jobs to run. */ |
| 130 | cpu_need_resched(ci, RESCHED_KPREEMPT); |
| 131 | break; |
| 132 | default: |
| 133 | if (spc->spc_flags & SPCF_SHOULDYIELD) { |
| 134 | /* |
| 135 | * Process is stuck in kernel somewhere, probably |
| 136 | * due to buggy or inefficient code. Force a |
| 137 | * kernel preemption. |
| 138 | */ |
| 139 | cpu_need_resched(ci, RESCHED_KPREEMPT); |
| 140 | } else if (spc->spc_flags & SPCF_SEENRR) { |
| 141 | /* |
| 142 | * The process has already been through a roundrobin |
| 143 | * without switching and may be hogging the CPU. |
| 144 | * Indicate that the process should yield. |
| 145 | */ |
| 146 | spc->spc_flags |= SPCF_SHOULDYIELD; |
| 147 | cpu_need_resched(ci, 0); |
| 148 | } else { |
| 149 | spc->spc_flags |= SPCF_SEENRR; |
| 150 | } |
| 151 | break; |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | /* |
| 156 | * Why PRIO_MAX - 2? From setpriority(2): |
| 157 | * |
| 158 | * prio is a value in the range -20 to 20. The default priority is |
| 159 | * 0; lower priorities cause more favorable scheduling. A value of |
| 160 | * 19 or 20 will schedule a process only when nothing at priority <= |
| 161 | * 0 is runnable. |
| 162 | * |
| 163 | * This gives estcpu influence over 18 priority levels, and leaves nice |
| 164 | * with 40 levels. One way to think about it is that nice has 20 levels |
| 165 | * either side of estcpu's 18. |
| 166 | */ |
| 167 | #define ESTCPU_SHIFT 11 |
| 168 | #define ESTCPU_MAX ((PRIO_MAX - 2) << ESTCPU_SHIFT) |
| 169 | #define ESTCPU_ACCUM (1 << (ESTCPU_SHIFT - 1)) |
| 170 | #define ESTCPULIM(e) min((e), ESTCPU_MAX) |
| 171 | |
| 172 | /* |
| 173 | * Constants for digital decay and forget: |
| 174 | * 90% of (l_estcpu) usage in 5 * loadav time |
| 175 | * 95% of (l_pctcpu) usage in 60 seconds (load insensitive) |
| 176 | * Note that, as ps(1) mentions, this can let percentages |
| 177 | * total over 100% (I've seen 137.9% for 3 processes). |
| 178 | * |
| 179 | * Note that hardclock updates l_estcpu and l_cpticks independently. |
| 180 | * |
| 181 | * We wish to decay away 90% of l_estcpu in (5 * loadavg) seconds. |
| 182 | * That is, the system wants to compute a value of decay such |
| 183 | * that the following for loop: |
| 184 | * for (i = 0; i < (5 * loadavg); i++) |
| 185 | * l_estcpu *= decay; |
| 186 | * will compute |
| 187 | * l_estcpu *= 0.1; |
| 188 | * for all values of loadavg: |
| 189 | * |
| 190 | * Mathematically this loop can be expressed by saying: |
| 191 | * decay ** (5 * loadavg) ~= .1 |
| 192 | * |
| 193 | * The system computes decay as: |
| 194 | * decay = (2 * loadavg) / (2 * loadavg + 1) |
| 195 | * |
| 196 | * We wish to prove that the system's computation of decay |
| 197 | * will always fulfill the equation: |
| 198 | * decay ** (5 * loadavg) ~= .1 |
| 199 | * |
| 200 | * If we compute b as: |
| 201 | * b = 2 * loadavg |
| 202 | * then |
| 203 | * decay = b / (b + 1) |
| 204 | * |
| 205 | * We now need to prove two things: |
| 206 | * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1) |
| 207 | * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg) |
| 208 | * |
| 209 | * Facts: |
| 210 | * For x close to zero, exp(x) =~ 1 + x, since |
| 211 | * exp(x) = 0! + x**1/1! + x**2/2! + ... . |
| 212 | * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b. |
| 213 | * For x close to zero, ln(1+x) =~ x, since |
| 214 | * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1 |
| 215 | * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1). |
| 216 | * ln(.1) =~ -2.30 |
| 217 | * |
| 218 | * Proof of (1): |
| 219 | * Solve (factor)**(power) =~ .1 given power (5*loadav): |
| 220 | * solving for factor, |
| 221 | * ln(factor) =~ (-2.30/5*loadav), or |
| 222 | * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) = |
| 223 | * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED |
| 224 | * |
| 225 | * Proof of (2): |
| 226 | * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)): |
| 227 | * solving for power, |
| 228 | * power*ln(b/(b+1)) =~ -2.30, or |
| 229 | * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED |
| 230 | * |
| 231 | * Actual power values for the implemented algorithm are as follows: |
| 232 | * loadav: 1 2 3 4 |
| 233 | * power: 5.68 10.32 14.94 19.55 |
| 234 | */ |
| 235 | |
| 236 | /* calculations for digital decay to forget 90% of usage in 5*loadav sec */ |
| 237 | #define loadfactor(loadav) (2 * (loadav) / ncpu) |
| 238 | |
| 239 | static fixpt_t |
| 240 | decay_cpu(fixpt_t loadfac, fixpt_t estcpu) |
| 241 | { |
| 242 | |
| 243 | if (estcpu == 0) { |
| 244 | return 0; |
| 245 | } |
| 246 | |
| 247 | #if !defined(_LP64) |
| 248 | /* avoid 64bit arithmetics. */ |
| 249 | #define FIXPT_MAX ((fixpt_t)((UINTMAX_C(1) << sizeof(fixpt_t) * CHAR_BIT) - 1)) |
| 250 | if (__predict_true(loadfac <= FIXPT_MAX / ESTCPU_MAX)) { |
| 251 | return estcpu * loadfac / (loadfac + FSCALE); |
| 252 | } |
| 253 | #endif /* !defined(_LP64) */ |
| 254 | |
| 255 | return (uint64_t)estcpu * loadfac / (loadfac + FSCALE); |
| 256 | } |
| 257 | |
| 258 | /* |
| 259 | * For all load averages >= 1 and max l_estcpu of (255 << ESTCPU_SHIFT), |
| 260 | * sleeping for at least seven times the loadfactor will decay l_estcpu to |
| 261 | * less than (1 << ESTCPU_SHIFT). |
| 262 | * |
| 263 | * note that our ESTCPU_MAX is actually much smaller than (255 << ESTCPU_SHIFT). |
| 264 | */ |
| 265 | static fixpt_t |
| 266 | decay_cpu_batch(fixpt_t loadfac, fixpt_t estcpu, unsigned int n) |
| 267 | { |
| 268 | |
| 269 | if ((n << FSHIFT) >= 7 * loadfac) { |
| 270 | return 0; |
| 271 | } |
| 272 | |
| 273 | while (estcpu != 0 && n > 1) { |
| 274 | estcpu = decay_cpu(loadfac, estcpu); |
| 275 | n--; |
| 276 | } |
| 277 | |
| 278 | return estcpu; |
| 279 | } |
| 280 | |
| 281 | /* |
| 282 | * sched_pstats_hook: |
| 283 | * |
| 284 | * Periodically called from sched_pstats(); used to recalculate priorities. |
| 285 | */ |
| 286 | void |
| 287 | sched_pstats_hook(struct lwp *l, int batch) |
| 288 | { |
| 289 | fixpt_t loadfac; |
| 290 | |
| 291 | /* |
| 292 | * If the LWP has slept an entire second, stop recalculating |
| 293 | * its priority until it wakes up. |
| 294 | */ |
| 295 | KASSERT(lwp_locked(l, NULL)); |
| 296 | if (l->l_stat == LSSLEEP || l->l_stat == LSSTOP || |
| 297 | l->l_stat == LSSUSPENDED) { |
| 298 | if (l->l_slptime > 1) { |
| 299 | return; |
| 300 | } |
| 301 | } |
| 302 | loadfac = 2 * (averunnable.ldavg[0]); |
| 303 | l->l_estcpu = decay_cpu(loadfac, l->l_estcpu); |
| 304 | resetpriority(l); |
| 305 | } |
| 306 | |
| 307 | /* |
| 308 | * Recalculate the priority of a process after it has slept for a while. |
| 309 | */ |
| 310 | static void |
| 311 | updatepri(struct lwp *l) |
| 312 | { |
| 313 | fixpt_t loadfac; |
| 314 | |
| 315 | KASSERT(lwp_locked(l, NULL)); |
| 316 | KASSERT(l->l_slptime > 1); |
| 317 | |
| 318 | loadfac = loadfactor(averunnable.ldavg[0]); |
| 319 | |
| 320 | l->l_slptime--; /* the first time was done in sched_pstats */ |
| 321 | l->l_estcpu = decay_cpu_batch(loadfac, l->l_estcpu, l->l_slptime); |
| 322 | resetpriority(l); |
| 323 | } |
| 324 | |
| 325 | void |
| 326 | sched_rqinit(void) |
| 327 | { |
| 328 | |
| 329 | } |
| 330 | |
| 331 | void |
| 332 | sched_setrunnable(struct lwp *l) |
| 333 | { |
| 334 | |
| 335 | if (l->l_slptime > 1) |
| 336 | updatepri(l); |
| 337 | } |
| 338 | |
| 339 | void |
| 340 | sched_nice(struct proc *p, int n) |
| 341 | { |
| 342 | struct lwp *l; |
| 343 | |
| 344 | KASSERT(mutex_owned(p->p_lock)); |
| 345 | |
| 346 | p->p_nice = n; |
| 347 | LIST_FOREACH(l, &p->p_lwps, l_sibling) { |
| 348 | lwp_lock(l); |
| 349 | resetpriority(l); |
| 350 | lwp_unlock(l); |
| 351 | } |
| 352 | } |
| 353 | |
| 354 | /* |
| 355 | * Recompute the priority of an LWP. Arrange to reschedule if |
| 356 | * the resulting priority is better than that of the current LWP. |
| 357 | */ |
| 358 | static void |
| 359 | resetpriority(struct lwp *l) |
| 360 | { |
| 361 | pri_t pri; |
| 362 | struct proc *p = l->l_proc; |
| 363 | |
| 364 | KASSERT(lwp_locked(l, NULL)); |
| 365 | |
| 366 | if (l->l_class != SCHED_OTHER) |
| 367 | return; |
| 368 | |
| 369 | /* See comments above ESTCPU_SHIFT definition. */ |
| 370 | pri = (PRI_KERNEL - 1) - (l->l_estcpu >> ESTCPU_SHIFT) - p->p_nice; |
| 371 | pri = imax(pri, 0); |
| 372 | if (pri != l->l_priority) |
| 373 | lwp_changepri(l, pri); |
| 374 | } |
| 375 | |
| 376 | /* |
| 377 | * We adjust the priority of the current LWP. The priority of a LWP |
| 378 | * gets worse as it accumulates CPU time. The CPU usage estimator (l_estcpu) |
| 379 | * is increased here. The formula for computing priorities will compute a |
| 380 | * different value each time l_estcpu increases. This can cause a switch, |
| 381 | * but unless the priority crosses a PPQ boundary the actual queue will not |
| 382 | * change. The CPU usage estimator ramps up quite quickly when the process |
| 383 | * is running (linearly), and decays away exponentially, at a rate which is |
| 384 | * proportionally slower when the system is busy. The basic principle is |
| 385 | * that the system will 90% forget that the process used a lot of CPU time |
| 386 | * in 5 * loadav seconds. This causes the system to favor processes which |
| 387 | * haven't run much recently, and to round-robin among other processes. |
| 388 | */ |
| 389 | |
| 390 | void |
| 391 | sched_schedclock(struct lwp *l) |
| 392 | { |
| 393 | |
| 394 | if (l->l_class != SCHED_OTHER) |
| 395 | return; |
| 396 | |
| 397 | KASSERT(!CURCPU_IDLE_P()); |
| 398 | l->l_estcpu = ESTCPULIM(l->l_estcpu + ESTCPU_ACCUM); |
| 399 | lwp_lock(l); |
| 400 | resetpriority(l); |
| 401 | lwp_unlock(l); |
| 402 | } |
| 403 | |
| 404 | /* |
| 405 | * sched_proc_fork: |
| 406 | * |
| 407 | * Inherit the parent's scheduler history. |
| 408 | */ |
| 409 | void |
| 410 | sched_proc_fork(struct proc *parent, struct proc *child) |
| 411 | { |
| 412 | lwp_t *pl; |
| 413 | |
| 414 | KASSERT(mutex_owned(parent->p_lock)); |
| 415 | |
| 416 | pl = LIST_FIRST(&parent->p_lwps); |
| 417 | child->p_estcpu_inherited = pl->l_estcpu; |
| 418 | child->p_forktime = sched_pstats_ticks; |
| 419 | } |
| 420 | |
| 421 | /* |
| 422 | * sched_proc_exit: |
| 423 | * |
| 424 | * Chargeback parents for the sins of their children. |
| 425 | */ |
| 426 | void |
| 427 | sched_proc_exit(struct proc *parent, struct proc *child) |
| 428 | { |
| 429 | fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); |
| 430 | fixpt_t estcpu; |
| 431 | lwp_t *pl, *cl; |
| 432 | |
| 433 | /* XXX Only if parent != init?? */ |
| 434 | |
| 435 | mutex_enter(parent->p_lock); |
| 436 | pl = LIST_FIRST(&parent->p_lwps); |
| 437 | cl = LIST_FIRST(&child->p_lwps); |
| 438 | estcpu = decay_cpu_batch(loadfac, child->p_estcpu_inherited, |
| 439 | sched_pstats_ticks - child->p_forktime); |
| 440 | if (cl->l_estcpu > estcpu) { |
| 441 | lwp_lock(pl); |
| 442 | pl->l_estcpu = ESTCPULIM(pl->l_estcpu + cl->l_estcpu - estcpu); |
| 443 | lwp_unlock(pl); |
| 444 | } |
| 445 | mutex_exit(parent->p_lock); |
| 446 | } |
| 447 | |
| 448 | void |
| 449 | sched_wakeup(struct lwp *l) |
| 450 | { |
| 451 | |
| 452 | } |
| 453 | |
| 454 | void |
| 455 | sched_slept(struct lwp *l) |
| 456 | { |
| 457 | |
| 458 | } |
| 459 | |
| 460 | void |
| 461 | sched_lwp_fork(struct lwp *l1, struct lwp *l2) |
| 462 | { |
| 463 | |
| 464 | l2->l_estcpu = l1->l_estcpu; |
| 465 | } |
| 466 | |
| 467 | void |
| 468 | sched_lwp_collect(struct lwp *t) |
| 469 | { |
| 470 | lwp_t *l; |
| 471 | |
| 472 | /* Absorb estcpu value of collected LWP. */ |
| 473 | l = curlwp; |
| 474 | lwp_lock(l); |
| 475 | l->l_estcpu += t->l_estcpu; |
| 476 | lwp_unlock(l); |
| 477 | } |
| 478 | |
| 479 | void |
| 480 | sched_oncpu(lwp_t *l) |
| 481 | { |
| 482 | |
| 483 | } |
| 484 | |
| 485 | void |
| 486 | sched_newts(lwp_t *l) |
| 487 | { |
| 488 | |
| 489 | } |
| 490 | |
| 491 | /* |
| 492 | * Sysctl nodes and initialization. |
| 493 | */ |
| 494 | |
| 495 | static int |
| 496 | sysctl_sched_rtts(SYSCTLFN_ARGS) |
| 497 | { |
| 498 | struct sysctlnode node; |
| 499 | int rttsms = hztoms(rrticks); |
| 500 | |
| 501 | node = *rnode; |
| 502 | node.sysctl_data = &rttsms; |
| 503 | return sysctl_lookup(SYSCTLFN_CALL(&node)); |
| 504 | } |
| 505 | |
| 506 | SYSCTL_SETUP(sysctl_sched_4bsd_setup, "sysctl sched setup" ) |
| 507 | { |
| 508 | const struct sysctlnode *node = NULL; |
| 509 | |
| 510 | sysctl_createv(clog, 0, NULL, &node, |
| 511 | CTLFLAG_PERMANENT, |
| 512 | CTLTYPE_NODE, "sched" , |
| 513 | SYSCTL_DESCR("Scheduler options" ), |
| 514 | NULL, 0, NULL, 0, |
| 515 | CTL_KERN, CTL_CREATE, CTL_EOL); |
| 516 | |
| 517 | if (node == NULL) |
| 518 | return; |
| 519 | |
| 520 | rrticks = hz / 10; |
| 521 | |
| 522 | sysctl_createv(NULL, 0, &node, NULL, |
| 523 | CTLFLAG_PERMANENT, |
| 524 | CTLTYPE_STRING, "name" , NULL, |
| 525 | NULL, 0, __UNCONST("4.4BSD" ), 0, |
| 526 | CTL_CREATE, CTL_EOL); |
| 527 | sysctl_createv(NULL, 0, &node, NULL, |
| 528 | CTLFLAG_PERMANENT, |
| 529 | CTLTYPE_INT, "rtts" , |
| 530 | SYSCTL_DESCR("Round-robin time quantum (in milliseconds)" ), |
| 531 | sysctl_sched_rtts, 0, NULL, 0, |
| 532 | CTL_CREATE, CTL_EOL); |
| 533 | } |
| 534 | |