1 /* $OpenBSD: sched_bsd.c,v 1.65 2020/12/10 04:26:50 gnezdo 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 #include <sys/tracepoint.h> 52 53 #ifdef KTRACE 54 #include <sys/ktrace.h> 55 #endif 56 57 58 int lbolt; /* once a second sleep address */ 59 int rrticks_init; /* # of hardclock ticks per roundrobin() */ 60 61 #ifdef MULTIPROCESSOR 62 struct __mp_lock sched_lock; 63 #endif 64 65 void schedcpu(void *); 66 uint32_t decay_aftersleep(uint32_t, uint32_t); 67 68 void 69 scheduler_start(void) 70 { 71 static struct timeout schedcpu_to; 72 73 /* 74 * We avoid polluting the global namespace by keeping the scheduler 75 * timeouts static in this function. 76 * We setup the timeout here and kick schedcpu once to make it do 77 * its job. 78 */ 79 timeout_set(&schedcpu_to, schedcpu, &schedcpu_to); 80 81 rrticks_init = hz / 10; 82 schedcpu(&schedcpu_to); 83 } 84 85 /* 86 * Force switch among equal priority processes every 100ms. 87 */ 88 void 89 roundrobin(struct cpu_info *ci) 90 { 91 struct schedstate_percpu *spc = &ci->ci_schedstate; 92 93 spc->spc_rrticks = rrticks_init; 94 95 if (ci->ci_curproc != NULL) { 96 if (spc->spc_schedflags & SPCF_SEENRR) { 97 /* 98 * The process has already been through a roundrobin 99 * without switching and may be hogging the CPU. 100 * Indicate that the process should yield. 101 */ 102 atomic_setbits_int(&spc->spc_schedflags, 103 SPCF_SHOULDYIELD); 104 } else { 105 atomic_setbits_int(&spc->spc_schedflags, 106 SPCF_SEENRR); 107 } 108 } 109 110 if (spc->spc_nrun) 111 need_resched(ci); 112 } 113 114 /* 115 * Constants for digital decay and forget: 116 * 90% of (p_estcpu) usage in 5 * loadav time 117 * 95% of (p_pctcpu) usage in 60 seconds (load insensitive) 118 * Note that, as ps(1) mentions, this can let percentages 119 * total over 100% (I've seen 137.9% for 3 processes). 120 * 121 * Note that hardclock updates p_estcpu and p_cpticks independently. 122 * 123 * We wish to decay away 90% of p_estcpu in (5 * loadavg) seconds. 124 * That is, the system wants to compute a value of decay such 125 * that the following for loop: 126 * for (i = 0; i < (5 * loadavg); i++) 127 * p_estcpu *= decay; 128 * will compute 129 * p_estcpu *= 0.1; 130 * for all values of loadavg: 131 * 132 * Mathematically this loop can be expressed by saying: 133 * decay ** (5 * loadavg) ~= .1 134 * 135 * The system computes decay as: 136 * decay = (2 * loadavg) / (2 * loadavg + 1) 137 * 138 * We wish to prove that the system's computation of decay 139 * will always fulfill the equation: 140 * decay ** (5 * loadavg) ~= .1 141 * 142 * If we compute b as: 143 * b = 2 * loadavg 144 * then 145 * decay = b / (b + 1) 146 * 147 * We now need to prove two things: 148 * 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1) 149 * 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg) 150 * 151 * Facts: 152 * For x close to zero, exp(x) =~ 1 + x, since 153 * exp(x) = 0! + x**1/1! + x**2/2! + ... . 154 * therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b. 155 * For x close to zero, ln(1+x) =~ x, since 156 * ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1 157 * therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1). 158 * ln(.1) =~ -2.30 159 * 160 * Proof of (1): 161 * Solve (factor)**(power) =~ .1 given power (5*loadav): 162 * solving for factor, 163 * ln(factor) =~ (-2.30/5*loadav), or 164 * factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) = 165 * exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED 166 * 167 * Proof of (2): 168 * Solve (factor)**(power) =~ .1 given factor == (b/(b+1)): 169 * solving for power, 170 * power*ln(b/(b+1)) =~ -2.30, or 171 * power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED 172 * 173 * Actual power values for the implemented algorithm are as follows: 174 * loadav: 1 2 3 4 175 * power: 5.68 10.32 14.94 19.55 176 */ 177 178 /* calculations for digital decay to forget 90% of usage in 5*loadav sec */ 179 #define loadfactor(loadav) (2 * (loadav)) 180 #define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE)) 181 182 /* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ 183 fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ 184 185 /* 186 * If `ccpu' is not equal to `exp(-1/20)' and you still want to use the 187 * faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below 188 * and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT). 189 * 190 * To estimate CCPU_SHIFT for exp(-1/20), the following formula was used: 191 * 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits). 192 * 193 * If you don't want to bother with the faster/more-accurate formula, you 194 * can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate 195 * (more general) method of calculating the %age of CPU used by a process. 196 */ 197 #define CCPU_SHIFT 11 198 199 /* 200 * Recompute process priorities, every second. 201 */ 202 void 203 schedcpu(void *arg) 204 { 205 struct timeout *to = (struct timeout *)arg; 206 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 207 struct proc *p; 208 int s; 209 unsigned int newcpu; 210 int phz; 211 212 /* 213 * If we have a statistics clock, use that to calculate CPU 214 * time, otherwise revert to using the profiling clock (which, 215 * in turn, defaults to hz if there is no separate profiling 216 * clock available) 217 */ 218 phz = stathz ? stathz : profhz; 219 KASSERT(phz); 220 221 LIST_FOREACH(p, &allproc, p_list) { 222 /* 223 * Idle threads are never placed on the runqueue, 224 * therefore computing their priority is pointless. 225 */ 226 if (p->p_cpu != NULL && 227 p->p_cpu->ci_schedstate.spc_idleproc == p) 228 continue; 229 /* 230 * Increment sleep time (if sleeping). We ignore overflow. 231 */ 232 if (p->p_stat == SSLEEP || p->p_stat == SSTOP) 233 p->p_slptime++; 234 p->p_pctcpu = (p->p_pctcpu * ccpu) >> FSHIFT; 235 /* 236 * If the process has slept the entire second, 237 * stop recalculating its priority until it wakes up. 238 */ 239 if (p->p_slptime > 1) 240 continue; 241 SCHED_LOCK(s); 242 /* 243 * p_pctcpu is only for diagnostic tools such as ps. 244 */ 245 #if (FSHIFT >= CCPU_SHIFT) 246 p->p_pctcpu += (phz == 100)? 247 ((fixpt_t) p->p_cpticks) << (FSHIFT - CCPU_SHIFT): 248 100 * (((fixpt_t) p->p_cpticks) 249 << (FSHIFT - CCPU_SHIFT)) / phz; 250 #else 251 p->p_pctcpu += ((FSCALE - ccpu) * 252 (p->p_cpticks * FSCALE / phz)) >> FSHIFT; 253 #endif 254 p->p_cpticks = 0; 255 newcpu = (u_int) decay_cpu(loadfac, p->p_estcpu); 256 setpriority(p, newcpu, p->p_p->ps_nice); 257 258 if (p->p_stat == SRUN && 259 (p->p_runpri / SCHED_PPQ) != (p->p_usrpri / SCHED_PPQ)) { 260 remrunqueue(p); 261 setrunqueue(p->p_cpu, p, p->p_usrpri); 262 } 263 SCHED_UNLOCK(s); 264 } 265 uvm_meter(); 266 wakeup(&lbolt); 267 timeout_add_sec(to, 1); 268 } 269 270 /* 271 * Recalculate the priority of a process after it has slept for a while. 272 * For all load averages >= 1 and max p_estcpu of 255, sleeping for at 273 * least six times the loadfactor will decay p_estcpu to zero. 274 */ 275 uint32_t 276 decay_aftersleep(uint32_t estcpu, uint32_t slptime) 277 { 278 fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); 279 uint32_t newcpu; 280 281 if (slptime > 5 * loadfac) 282 newcpu = 0; 283 else { 284 newcpu = estcpu; 285 slptime--; /* the first time was done in schedcpu */ 286 while (newcpu && --slptime) 287 newcpu = decay_cpu(loadfac, newcpu); 288 289 } 290 291 return (newcpu); 292 } 293 294 /* 295 * General yield call. Puts the current process back on its run queue and 296 * performs a voluntary context switch. 297 */ 298 void 299 yield(void) 300 { 301 struct proc *p = curproc; 302 int s; 303 304 SCHED_LOCK(s); 305 setrunqueue(p->p_cpu, p, p->p_usrpri); 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 setrunqueue(p->p_cpu, p, p->p_usrpri); 325 p->p_ru.ru_nivcsw++; 326 mi_switch(); 327 SCHED_UNLOCK(s); 328 } 329 330 void 331 mi_switch(void) 332 { 333 struct schedstate_percpu *spc = &curcpu()->ci_schedstate; 334 struct proc *p = curproc; 335 struct proc *nextproc; 336 struct process *pr = p->p_p; 337 struct timespec ts; 338 #ifdef MULTIPROCESSOR 339 int hold_count; 340 int sched_count; 341 #endif 342 343 assertwaitok(); 344 KASSERT(p->p_stat != SONPROC); 345 346 SCHED_ASSERT_LOCKED(); 347 348 #ifdef MULTIPROCESSOR 349 /* 350 * Release the kernel_lock, as we are about to yield the CPU. 351 */ 352 sched_count = __mp_release_all_but_one(&sched_lock); 353 if (_kernel_lock_held()) 354 hold_count = __mp_release_all(&kernel_lock); 355 else 356 hold_count = 0; 357 #endif 358 359 /* 360 * Compute the amount of time during which the current 361 * process was running, and add that to its total so far. 362 */ 363 nanouptime(&ts); 364 if (timespeccmp(&ts, &spc->spc_runtime, <)) { 365 #if 0 366 printf("uptime is not monotonic! " 367 "ts=%lld.%09lu, runtime=%lld.%09lu\n", 368 (long long)tv.tv_sec, tv.tv_nsec, 369 (long long)spc->spc_runtime.tv_sec, 370 spc->spc_runtime.tv_nsec); 371 #endif 372 } else { 373 timespecsub(&ts, &spc->spc_runtime, &ts); 374 timespecadd(&p->p_rtime, &ts, &p->p_rtime); 375 } 376 377 /* add the time counts for this thread to the process's total */ 378 tuagg_unlocked(pr, p); 379 380 /* 381 * Process is about to yield the CPU; clear the appropriate 382 * scheduling flags. 383 */ 384 atomic_clearbits_int(&spc->spc_schedflags, SPCF_SWITCHCLEAR); 385 386 nextproc = sched_chooseproc(); 387 388 if (p != nextproc) { 389 uvmexp.swtch++; 390 TRACEPOINT(sched, off__cpu, nextproc->p_tid, 391 nextproc->p_p->ps_pid); 392 cpu_switchto(p, nextproc); 393 TRACEPOINT(sched, on__cpu, NULL); 394 } else { 395 TRACEPOINT(sched, remain__cpu, NULL); 396 p->p_stat = SONPROC; 397 } 398 399 clear_resched(curcpu()); 400 401 SCHED_ASSERT_LOCKED(); 402 403 /* 404 * To preserve lock ordering, we need to release the sched lock 405 * and grab it after we grab the big lock. 406 * In the future, when the sched lock isn't recursive, we'll 407 * just release it here. 408 */ 409 #ifdef MULTIPROCESSOR 410 __mp_unlock(&sched_lock); 411 #endif 412 413 SCHED_ASSERT_UNLOCKED(); 414 415 smr_idle(); 416 417 /* 418 * We're running again; record our new start time. We might 419 * be running on a new CPU now, so don't use the cache'd 420 * schedstate_percpu pointer. 421 */ 422 KASSERT(p->p_cpu == curcpu()); 423 424 nanouptime(&p->p_cpu->ci_schedstate.spc_runtime); 425 426 #ifdef MULTIPROCESSOR 427 /* 428 * Reacquire the kernel_lock now. We do this after we've 429 * released the scheduler lock to avoid deadlock, and before 430 * we reacquire the interlock and the scheduler lock. 431 */ 432 if (hold_count) 433 __mp_acquire_count(&kernel_lock, hold_count); 434 __mp_acquire_count(&sched_lock, sched_count + 1); 435 #endif 436 } 437 438 /* 439 * Change process state to be runnable, 440 * placing it on the run queue. 441 */ 442 void 443 setrunnable(struct proc *p) 444 { 445 struct process *pr = p->p_p; 446 u_char prio; 447 448 SCHED_ASSERT_LOCKED(); 449 450 switch (p->p_stat) { 451 case 0: 452 case SRUN: 453 case SONPROC: 454 case SDEAD: 455 case SIDL: 456 default: 457 panic("setrunnable"); 458 case SSTOP: 459 /* 460 * If we're being traced (possibly because someone attached us 461 * while we were stopped), check for a signal from the debugger. 462 */ 463 if ((pr->ps_flags & PS_TRACED) != 0 && pr->ps_xsig != 0) 464 atomic_setbits_int(&p->p_siglist, sigmask(pr->ps_xsig)); 465 prio = p->p_usrpri; 466 unsleep(p); 467 break; 468 case SSLEEP: 469 prio = p->p_slppri; 470 unsleep(p); /* e.g. when sending signals */ 471 break; 472 } 473 setrunqueue(NULL, p, prio); 474 if (p->p_slptime > 1) { 475 uint32_t newcpu; 476 477 newcpu = decay_aftersleep(p->p_estcpu, p->p_slptime); 478 setpriority(p, newcpu, pr->ps_nice); 479 } 480 p->p_slptime = 0; 481 } 482 483 /* 484 * Compute the priority of a process. 485 */ 486 void 487 setpriority(struct proc *p, uint32_t newcpu, uint8_t nice) 488 { 489 unsigned int newprio; 490 491 newprio = min((PUSER + newcpu + NICE_WEIGHT * (nice - NZERO)), MAXPRI); 492 493 SCHED_ASSERT_LOCKED(); 494 p->p_estcpu = newcpu; 495 p->p_usrpri = newprio; 496 } 497 498 /* 499 * We adjust the priority of the current process. The priority of a process 500 * gets worse as it accumulates CPU time. The cpu usage estimator (p_estcpu) 501 * is increased here. The formula for computing priorities (in kern_synch.c) 502 * will compute a different value each time p_estcpu increases. This can 503 * cause a switch, but unless the priority crosses a PPQ boundary the actual 504 * queue will not change. The cpu usage estimator ramps up quite quickly 505 * when the process is running (linearly), and decays away exponentially, at 506 * a rate which is proportionally slower when the system is busy. The basic 507 * principle is that the system will 90% forget that the process used a lot 508 * of CPU time in 5 * loadav seconds. This causes the system to favor 509 * processes which haven't run much recently, and to round-robin among other 510 * processes. 511 */ 512 void 513 schedclock(struct proc *p) 514 { 515 struct cpu_info *ci = curcpu(); 516 struct schedstate_percpu *spc = &ci->ci_schedstate; 517 uint32_t newcpu; 518 int s; 519 520 if (p == spc->spc_idleproc || spc->spc_spinning) 521 return; 522 523 SCHED_LOCK(s); 524 newcpu = ESTCPULIM(p->p_estcpu + 1); 525 setpriority(p, newcpu, p->p_p->ps_nice); 526 SCHED_UNLOCK(s); 527 } 528 529 void (*cpu_setperf)(int); 530 531 #define PERFPOL_MANUAL 0 532 #define PERFPOL_AUTO 1 533 #define PERFPOL_HIGH 2 534 int perflevel = 100; 535 int perfpolicy = PERFPOL_MANUAL; 536 537 #ifndef SMALL_KERNEL 538 /* 539 * The code below handles CPU throttling. 540 */ 541 #include <sys/sysctl.h> 542 543 void setperf_auto(void *); 544 struct timeout setperf_to = TIMEOUT_INITIALIZER(setperf_auto, NULL); 545 546 void 547 setperf_auto(void *v) 548 { 549 static uint64_t *idleticks, *totalticks; 550 static int downbeats; 551 552 int i, j; 553 int speedup; 554 CPU_INFO_ITERATOR cii; 555 struct cpu_info *ci; 556 uint64_t idle, total, allidle, alltotal; 557 558 if (perfpolicy != PERFPOL_AUTO) 559 return; 560 561 if (!idleticks) 562 if (!(idleticks = mallocarray(ncpusfound, sizeof(*idleticks), 563 M_DEVBUF, M_NOWAIT | M_ZERO))) 564 return; 565 if (!totalticks) 566 if (!(totalticks = mallocarray(ncpusfound, sizeof(*totalticks), 567 M_DEVBUF, M_NOWAIT | M_ZERO))) { 568 free(idleticks, M_DEVBUF, 569 sizeof(*idleticks) * ncpusfound); 570 return; 571 } 572 573 alltotal = allidle = 0; 574 j = 0; 575 speedup = 0; 576 CPU_INFO_FOREACH(cii, ci) { 577 if (!cpu_is_online(ci)) 578 continue; 579 total = 0; 580 for (i = 0; i < CPUSTATES; i++) { 581 total += ci->ci_schedstate.spc_cp_time[i]; 582 } 583 total -= totalticks[j]; 584 idle = ci->ci_schedstate.spc_cp_time[CP_IDLE] - idleticks[j]; 585 if (idle < total / 3) 586 speedup = 1; 587 alltotal += total; 588 allidle += idle; 589 idleticks[j] += idle; 590 totalticks[j] += total; 591 j++; 592 } 593 if (allidle < alltotal / 2) 594 speedup = 1; 595 if (speedup) 596 downbeats = 5; 597 598 if (speedup && perflevel != 100) { 599 perflevel = 100; 600 cpu_setperf(perflevel); 601 } else if (!speedup && perflevel != 0 && --downbeats <= 0) { 602 perflevel = 0; 603 cpu_setperf(perflevel); 604 } 605 606 timeout_add_msec(&setperf_to, 100); 607 } 608 609 int 610 sysctl_hwsetperf(void *oldp, size_t *oldlenp, void *newp, size_t newlen) 611 { 612 int err; 613 614 if (!cpu_setperf) 615 return EOPNOTSUPP; 616 617 if (perfpolicy != PERFPOL_MANUAL) 618 return sysctl_rdint(oldp, oldlenp, newp, perflevel); 619 620 err = sysctl_int_bounded(oldp, oldlenp, newp, newlen, 621 &perflevel, 0, 100); 622 if (err) 623 return err; 624 cpu_setperf(perflevel); 625 return 0; 626 } 627 628 int 629 sysctl_hwperfpolicy(void *oldp, size_t *oldlenp, void *newp, size_t newlen) 630 { 631 char policy[32]; 632 int err; 633 634 if (!cpu_setperf) 635 return EOPNOTSUPP; 636 637 switch (perfpolicy) { 638 case PERFPOL_MANUAL: 639 strlcpy(policy, "manual", sizeof(policy)); 640 break; 641 case PERFPOL_AUTO: 642 strlcpy(policy, "auto", sizeof(policy)); 643 break; 644 case PERFPOL_HIGH: 645 strlcpy(policy, "high", sizeof(policy)); 646 break; 647 default: 648 strlcpy(policy, "unknown", sizeof(policy)); 649 break; 650 } 651 652 if (newp == NULL) 653 return sysctl_rdstring(oldp, oldlenp, newp, policy); 654 655 err = sysctl_string(oldp, oldlenp, newp, newlen, policy, sizeof(policy)); 656 if (err) 657 return err; 658 if (strcmp(policy, "manual") == 0) 659 perfpolicy = PERFPOL_MANUAL; 660 else if (strcmp(policy, "auto") == 0) 661 perfpolicy = PERFPOL_AUTO; 662 else if (strcmp(policy, "high") == 0) 663 perfpolicy = PERFPOL_HIGH; 664 else 665 return EINVAL; 666 667 if (perfpolicy == PERFPOL_AUTO) { 668 timeout_add_msec(&setperf_to, 200); 669 } else if (perfpolicy == PERFPOL_HIGH) { 670 perflevel = 100; 671 cpu_setperf(perflevel); 672 } 673 return 0; 674 } 675 #endif 676