1 /* $NetBSD: kern_clock.c,v 1.78 2001/11/12 15:25:06 lukem Exp $ */ 2 3 /*- 4 * Copyright (c) 2000 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. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /*- 41 * Copyright (c) 1982, 1986, 1991, 1993 42 * The Regents of the University of California. All rights reserved. 43 * (c) UNIX System Laboratories, Inc. 44 * All or some portions of this file are derived from material licensed 45 * to the University of California by American Telephone and Telegraph 46 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 47 * the permission of UNIX System Laboratories, Inc. 48 * 49 * Redistribution and use in source and binary forms, with or without 50 * modification, are permitted provided that the following conditions 51 * are met: 52 * 1. Redistributions of source code must retain the above copyright 53 * notice, this list of conditions and the following disclaimer. 54 * 2. Redistributions in binary form must reproduce the above copyright 55 * notice, this list of conditions and the following disclaimer in the 56 * documentation and/or other materials provided with the distribution. 57 * 3. All advertising materials mentioning features or use of this software 58 * must display the following acknowledgement: 59 * This product includes software developed by the University of 60 * California, Berkeley and its contributors. 61 * 4. Neither the name of the University nor the names of its contributors 62 * may be used to endorse or promote products derived from this software 63 * without specific prior written permission. 64 * 65 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 66 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 67 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 68 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 69 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 70 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 71 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 72 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 73 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 74 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 75 * SUCH DAMAGE. 76 * 77 * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 78 */ 79 80 #include <sys/cdefs.h> 81 __KERNEL_RCSID(0, "$NetBSD: kern_clock.c,v 1.78 2001/11/12 15:25:06 lukem Exp $"); 82 83 #include "opt_callout.h" 84 #include "opt_ntp.h" 85 86 #include <sys/param.h> 87 #include <sys/systm.h> 88 #include <sys/dkstat.h> 89 #include <sys/callout.h> 90 #include <sys/kernel.h> 91 #include <sys/proc.h> 92 #include <sys/resourcevar.h> 93 #include <sys/signalvar.h> 94 #include <uvm/uvm_extern.h> 95 #include <sys/sysctl.h> 96 #include <sys/timex.h> 97 #include <sys/sched.h> 98 #ifdef CALLWHEEL_STATS 99 #include <sys/device.h> 100 #endif 101 102 #include <machine/cpu.h> 103 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 104 #include <machine/intr.h> 105 #endif 106 107 #ifdef GPROF 108 #include <sys/gmon.h> 109 #endif 110 111 /* 112 * Clock handling routines. 113 * 114 * This code is written to operate with two timers that run independently of 115 * each other. The main clock, running hz times per second, is used to keep 116 * track of real time. The second timer handles kernel and user profiling, 117 * and does resource use estimation. If the second timer is programmable, 118 * it is randomized to avoid aliasing between the two clocks. For example, 119 * the randomization prevents an adversary from always giving up the cpu 120 * just before its quantum expires. Otherwise, it would never accumulate 121 * cpu ticks. The mean frequency of the second timer is stathz. 122 * 123 * If no second timer exists, stathz will be zero; in this case we drive 124 * profiling and statistics off the main clock. This WILL NOT be accurate; 125 * do not do it unless absolutely necessary. 126 * 127 * The statistics clock may (or may not) be run at a higher rate while 128 * profiling. This profile clock runs at profhz. We require that profhz 129 * be an integral multiple of stathz. 130 * 131 * If the statistics clock is running fast, it must be divided by the ratio 132 * profhz/stathz for statistics. (For profiling, every tick counts.) 133 */ 134 135 #ifdef NTP /* NTP phase-locked loop in kernel */ 136 /* 137 * Phase/frequency-lock loop (PLL/FLL) definitions 138 * 139 * The following variables are read and set by the ntp_adjtime() system 140 * call. 141 * 142 * time_state shows the state of the system clock, with values defined 143 * in the timex.h header file. 144 * 145 * time_status shows the status of the system clock, with bits defined 146 * in the timex.h header file. 147 * 148 * time_offset is used by the PLL/FLL to adjust the system time in small 149 * increments. 150 * 151 * time_constant determines the bandwidth or "stiffness" of the PLL. 152 * 153 * time_tolerance determines maximum frequency error or tolerance of the 154 * CPU clock oscillator and is a property of the architecture; however, 155 * in principle it could change as result of the presence of external 156 * discipline signals, for instance. 157 * 158 * time_precision is usually equal to the kernel tick variable; however, 159 * in cases where a precision clock counter or external clock is 160 * available, the resolution can be much less than this and depend on 161 * whether the external clock is working or not. 162 * 163 * time_maxerror is initialized by a ntp_adjtime() call and increased by 164 * the kernel once each second to reflect the maximum error bound 165 * growth. 166 * 167 * time_esterror is set and read by the ntp_adjtime() call, but 168 * otherwise not used by the kernel. 169 */ 170 int time_state = TIME_OK; /* clock state */ 171 int time_status = STA_UNSYNC; /* clock status bits */ 172 long time_offset = 0; /* time offset (us) */ 173 long time_constant = 0; /* pll time constant */ 174 long time_tolerance = MAXFREQ; /* frequency tolerance (scaled ppm) */ 175 long time_precision = 1; /* clock precision (us) */ 176 long time_maxerror = MAXPHASE; /* maximum error (us) */ 177 long time_esterror = MAXPHASE; /* estimated error (us) */ 178 179 /* 180 * The following variables establish the state of the PLL/FLL and the 181 * residual time and frequency offset of the local clock. The scale 182 * factors are defined in the timex.h header file. 183 * 184 * time_phase and time_freq are the phase increment and the frequency 185 * increment, respectively, of the kernel time variable. 186 * 187 * time_freq is set via ntp_adjtime() from a value stored in a file when 188 * the synchronization daemon is first started. Its value is retrieved 189 * via ntp_adjtime() and written to the file about once per hour by the 190 * daemon. 191 * 192 * time_adj is the adjustment added to the value of tick at each timer 193 * interrupt and is recomputed from time_phase and time_freq at each 194 * seconds rollover. 195 * 196 * time_reftime is the second's portion of the system time at the last 197 * call to ntp_adjtime(). It is used to adjust the time_freq variable 198 * and to increase the time_maxerror as the time since last update 199 * increases. 200 */ 201 long time_phase = 0; /* phase offset (scaled us) */ 202 long time_freq = 0; /* frequency offset (scaled ppm) */ 203 long time_adj = 0; /* tick adjust (scaled 1 / hz) */ 204 long time_reftime = 0; /* time at last adjustment (s) */ 205 206 #ifdef PPS_SYNC 207 /* 208 * The following variables are used only if the kernel PPS discipline 209 * code is configured (PPS_SYNC). The scale factors are defined in the 210 * timex.h header file. 211 * 212 * pps_time contains the time at each calibration interval, as read by 213 * microtime(). pps_count counts the seconds of the calibration 214 * interval, the duration of which is nominally pps_shift in powers of 215 * two. 216 * 217 * pps_offset is the time offset produced by the time median filter 218 * pps_tf[], while pps_jitter is the dispersion (jitter) measured by 219 * this filter. 220 * 221 * pps_freq is the frequency offset produced by the frequency median 222 * filter pps_ff[], while pps_stabil is the dispersion (wander) measured 223 * by this filter. 224 * 225 * pps_usec is latched from a high resolution counter or external clock 226 * at pps_time. Here we want the hardware counter contents only, not the 227 * contents plus the time_tv.usec as usual. 228 * 229 * pps_valid counts the number of seconds since the last PPS update. It 230 * is used as a watchdog timer to disable the PPS discipline should the 231 * PPS signal be lost. 232 * 233 * pps_glitch counts the number of seconds since the beginning of an 234 * offset burst more than tick/2 from current nominal offset. It is used 235 * mainly to suppress error bursts due to priority conflicts between the 236 * PPS interrupt and timer interrupt. 237 * 238 * pps_intcnt counts the calibration intervals for use in the interval- 239 * adaptation algorithm. It's just too complicated for words. 240 */ 241 struct timeval pps_time; /* kernel time at last interval */ 242 long pps_tf[] = {0, 0, 0}; /* pps time offset median filter (us) */ 243 long pps_offset = 0; /* pps time offset (us) */ 244 long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */ 245 long pps_ff[] = {0, 0, 0}; /* pps frequency offset median filter */ 246 long pps_freq = 0; /* frequency offset (scaled ppm) */ 247 long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */ 248 long pps_usec = 0; /* microsec counter at last interval */ 249 long pps_valid = PPS_VALID; /* pps signal watchdog counter */ 250 int pps_glitch = 0; /* pps signal glitch counter */ 251 int pps_count = 0; /* calibration interval counter (s) */ 252 int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */ 253 int pps_intcnt = 0; /* intervals at current duration */ 254 255 /* 256 * PPS signal quality monitors 257 * 258 * pps_jitcnt counts the seconds that have been discarded because the 259 * jitter measured by the time median filter exceeds the limit MAXTIME 260 * (100 us). 261 * 262 * pps_calcnt counts the frequency calibration intervals, which are 263 * variable from 4 s to 256 s. 264 * 265 * pps_errcnt counts the calibration intervals which have been discarded 266 * because the wander exceeds the limit MAXFREQ (100 ppm) or where the 267 * calibration interval jitter exceeds two ticks. 268 * 269 * pps_stbcnt counts the calibration intervals that have been discarded 270 * because the frequency wander exceeds the limit MAXFREQ / 4 (25 us). 271 */ 272 long pps_jitcnt = 0; /* jitter limit exceeded */ 273 long pps_calcnt = 0; /* calibration intervals */ 274 long pps_errcnt = 0; /* calibration errors */ 275 long pps_stbcnt = 0; /* stability limit exceeded */ 276 #endif /* PPS_SYNC */ 277 278 #ifdef EXT_CLOCK 279 /* 280 * External clock definitions 281 * 282 * The following definitions and declarations are used only if an 283 * external clock is configured on the system. 284 */ 285 #define CLOCK_INTERVAL 30 /* CPU clock update interval (s) */ 286 287 /* 288 * The clock_count variable is set to CLOCK_INTERVAL at each PPS 289 * interrupt and decremented once each second. 290 */ 291 int clock_count = 0; /* CPU clock counter */ 292 293 #ifdef HIGHBALL 294 /* 295 * The clock_offset and clock_cpu variables are used by the HIGHBALL 296 * interface. The clock_offset variable defines the offset between 297 * system time and the HIGBALL counters. The clock_cpu variable contains 298 * the offset between the system clock and the HIGHBALL clock for use in 299 * disciplining the kernel time variable. 300 */ 301 extern struct timeval clock_offset; /* Highball clock offset */ 302 long clock_cpu = 0; /* CPU clock adjust */ 303 #endif /* HIGHBALL */ 304 #endif /* EXT_CLOCK */ 305 #endif /* NTP */ 306 307 308 /* 309 * Bump a timeval by a small number of usec's. 310 */ 311 #define BUMPTIME(t, usec) { \ 312 volatile struct timeval *tp = (t); \ 313 long us; \ 314 \ 315 tp->tv_usec = us = tp->tv_usec + (usec); \ 316 if (us >= 1000000) { \ 317 tp->tv_usec = us - 1000000; \ 318 tp->tv_sec++; \ 319 } \ 320 } 321 322 int stathz; 323 int profhz; 324 int schedhz; 325 int profprocs; 326 int softclock_running; /* 1 => softclock() is running */ 327 static int psdiv; /* prof => stat divider */ 328 int psratio; /* ratio: prof / stat */ 329 int tickfix, tickfixinterval; /* used if tick not really integral */ 330 #ifndef NTP 331 static int tickfixcnt; /* accumulated fractional error */ 332 #else 333 int fixtick; /* used by NTP for same */ 334 int shifthz; 335 #endif 336 337 /* 338 * We might want ldd to load the both words from time at once. 339 * To succeed we need to be quadword aligned. 340 * The sparc already does that, and that it has worked so far is a fluke. 341 */ 342 volatile struct timeval time __attribute__((__aligned__(__alignof__(quad_t)))); 343 volatile struct timeval mono_time; 344 345 /* 346 * The callout mechanism is based on the work of Adam M. Costello and 347 * George Varghese, published in a technical report entitled "Redesigning 348 * the BSD Callout and Timer Facilities", and Justin Gibbs's subsequent 349 * integration into FreeBSD, modified for NetBSD by Jason R. Thorpe. 350 * 351 * The original work on the data structures used in this implementation 352 * was published by G. Varghese and A. Lauck in the paper "Hashed and 353 * Hierarchical Timing Wheels: Data Structures for the Efficient 354 * Implementation of a Timer Facility" in the Proceedings of the 11th 355 * ACM Annual Symposium on Operating System Principles, Austin, Texas, 356 * November 1987. 357 */ 358 struct callout_queue *callwheel; 359 int callwheelsize, callwheelbits, callwheelmask; 360 361 static struct callout *nextsoftcheck; /* next callout to be checked */ 362 363 #ifdef CALLWHEEL_STATS 364 int *callwheel_sizes; /* per-bucket length count */ 365 struct evcnt callwheel_collisions; /* number of hash collisions */ 366 struct evcnt callwheel_maxlength; /* length of the longest hash chain */ 367 struct evcnt callwheel_count; /* # callouts currently */ 368 struct evcnt callwheel_established; /* # callouts established */ 369 struct evcnt callwheel_fired; /* # callouts that fired */ 370 struct evcnt callwheel_disestablished; /* # callouts disestablished */ 371 struct evcnt callwheel_changed; /* # callouts changed */ 372 struct evcnt callwheel_softclocks; /* # times softclock() called */ 373 struct evcnt callwheel_softchecks; /* # checks per softclock() */ 374 struct evcnt callwheel_softempty; /* # empty buckets seen */ 375 struct evcnt callwheel_hintworked; /* # times hint saved scan */ 376 #endif /* CALLWHEEL_STATS */ 377 378 /* 379 * This value indicates the number of consecutive callouts that 380 * will be checked before we allow interrupts to have a chance 381 * again. 382 */ 383 #ifndef MAX_SOFTCLOCK_STEPS 384 #define MAX_SOFTCLOCK_STEPS 100 385 #endif 386 387 struct simplelock callwheel_slock; 388 389 #define CALLWHEEL_LOCK(s) \ 390 do { \ 391 s = splclock(); \ 392 simple_lock(&callwheel_slock); \ 393 } while (0) 394 395 #define CALLWHEEL_UNLOCK(s) \ 396 do { \ 397 simple_unlock(&callwheel_slock); \ 398 splx(s); \ 399 } while (0) 400 401 static void callout_stop_locked(struct callout *); 402 403 /* 404 * These are both protected by callwheel_lock. 405 * XXX SHOULD BE STATIC!! 406 */ 407 u_int64_t hardclock_ticks, softclock_ticks; 408 409 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 410 void softclock(void *); 411 void *softclock_si; 412 #endif 413 414 /* 415 * Initialize clock frequencies and start both clocks running. 416 */ 417 void 418 initclocks(void) 419 { 420 int i; 421 422 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 423 softclock_si = softintr_establish(IPL_SOFTCLOCK, softclock, NULL); 424 if (softclock_si == NULL) 425 panic("initclocks: unable to register softclock intr"); 426 #endif 427 428 /* 429 * Set divisors to 1 (normal case) and let the machine-specific 430 * code do its bit. 431 */ 432 psdiv = 1; 433 cpu_initclocks(); 434 435 /* 436 * Compute profhz/stathz/rrticks, and fix profhz if needed. 437 */ 438 i = stathz ? stathz : hz; 439 if (profhz == 0) 440 profhz = i; 441 psratio = profhz / i; 442 rrticks = hz / 10; 443 444 #ifdef NTP 445 switch (hz) { 446 case 1: 447 shifthz = SHIFT_SCALE - 0; 448 break; 449 case 2: 450 shifthz = SHIFT_SCALE - 1; 451 break; 452 case 4: 453 shifthz = SHIFT_SCALE - 2; 454 break; 455 case 8: 456 shifthz = SHIFT_SCALE - 3; 457 break; 458 case 16: 459 shifthz = SHIFT_SCALE - 4; 460 break; 461 case 32: 462 shifthz = SHIFT_SCALE - 5; 463 break; 464 case 60: 465 case 64: 466 shifthz = SHIFT_SCALE - 6; 467 break; 468 case 96: 469 case 100: 470 case 128: 471 shifthz = SHIFT_SCALE - 7; 472 break; 473 case 256: 474 shifthz = SHIFT_SCALE - 8; 475 break; 476 case 512: 477 shifthz = SHIFT_SCALE - 9; 478 break; 479 case 1000: 480 case 1024: 481 shifthz = SHIFT_SCALE - 10; 482 break; 483 case 1200: 484 case 2048: 485 shifthz = SHIFT_SCALE - 11; 486 break; 487 case 4096: 488 shifthz = SHIFT_SCALE - 12; 489 break; 490 case 8192: 491 shifthz = SHIFT_SCALE - 13; 492 break; 493 case 16384: 494 shifthz = SHIFT_SCALE - 14; 495 break; 496 case 32768: 497 shifthz = SHIFT_SCALE - 15; 498 break; 499 case 65536: 500 shifthz = SHIFT_SCALE - 16; 501 break; 502 default: 503 panic("weird hz"); 504 } 505 if (fixtick == 0) { 506 /* 507 * Give MD code a chance to set this to a better 508 * value; but, if it doesn't, we should. 509 */ 510 fixtick = (1000000 - (hz*tick)); 511 } 512 #endif 513 } 514 515 /* 516 * The real-time timer, interrupting hz times per second. 517 */ 518 void 519 hardclock(struct clockframe *frame) 520 { 521 struct proc *p; 522 int delta; 523 extern int tickdelta; 524 extern long timedelta; 525 struct cpu_info *ci = curcpu(); 526 #ifdef NTP 527 int time_update; 528 int ltemp; 529 #endif 530 531 p = curproc; 532 if (p) { 533 struct pstats *pstats; 534 535 /* 536 * Run current process's virtual and profile time, as needed. 537 */ 538 pstats = p->p_stats; 539 if (CLKF_USERMODE(frame) && 540 timerisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) && 541 itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) 542 psignal(p, SIGVTALRM); 543 if (timerisset(&pstats->p_timer[ITIMER_PROF].it_value) && 544 itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) 545 psignal(p, SIGPROF); 546 } 547 548 /* 549 * If no separate statistics clock is available, run it from here. 550 */ 551 if (stathz == 0) 552 statclock(frame); 553 if ((--ci->ci_schedstate.spc_rrticks) <= 0) 554 roundrobin(ci); 555 556 #if defined(MULTIPROCESSOR) 557 /* 558 * If we are not the primary CPU, we're not allowed to do 559 * any more work. 560 */ 561 if (CPU_IS_PRIMARY(ci) == 0) 562 return; 563 #endif 564 565 /* 566 * Increment the time-of-day. The increment is normally just 567 * ``tick''. If the machine is one which has a clock frequency 568 * such that ``hz'' would not divide the second evenly into 569 * milliseconds, a periodic adjustment must be applied. Finally, 570 * if we are still adjusting the time (see adjtime()), 571 * ``tickdelta'' may also be added in. 572 */ 573 delta = tick; 574 575 #ifndef NTP 576 if (tickfix) { 577 tickfixcnt += tickfix; 578 if (tickfixcnt >= tickfixinterval) { 579 delta++; 580 tickfixcnt -= tickfixinterval; 581 } 582 } 583 #endif /* !NTP */ 584 /* Imprecise 4bsd adjtime() handling */ 585 if (timedelta != 0) { 586 delta += tickdelta; 587 timedelta -= tickdelta; 588 } 589 590 #ifdef notyet 591 microset(); 592 #endif 593 594 #ifndef NTP 595 BUMPTIME(&time, delta); /* XXX Now done using NTP code below */ 596 #endif 597 BUMPTIME(&mono_time, delta); 598 599 #ifdef NTP 600 time_update = delta; 601 602 /* 603 * Compute the phase adjustment. If the low-order bits 604 * (time_phase) of the update overflow, bump the high-order bits 605 * (time_update). 606 */ 607 time_phase += time_adj; 608 if (time_phase <= -FINEUSEC) { 609 ltemp = -time_phase >> SHIFT_SCALE; 610 time_phase += ltemp << SHIFT_SCALE; 611 time_update -= ltemp; 612 } else if (time_phase >= FINEUSEC) { 613 ltemp = time_phase >> SHIFT_SCALE; 614 time_phase -= ltemp << SHIFT_SCALE; 615 time_update += ltemp; 616 } 617 618 #ifdef HIGHBALL 619 /* 620 * If the HIGHBALL board is installed, we need to adjust the 621 * external clock offset in order to close the hardware feedback 622 * loop. This will adjust the external clock phase and frequency 623 * in small amounts. The additional phase noise and frequency 624 * wander this causes should be minimal. We also need to 625 * discipline the kernel time variable, since the PLL is used to 626 * discipline the external clock. If the Highball board is not 627 * present, we discipline kernel time with the PLL as usual. We 628 * assume that the external clock phase adjustment (time_update) 629 * and kernel phase adjustment (clock_cpu) are less than the 630 * value of tick. 631 */ 632 clock_offset.tv_usec += time_update; 633 if (clock_offset.tv_usec >= 1000000) { 634 clock_offset.tv_sec++; 635 clock_offset.tv_usec -= 1000000; 636 } 637 if (clock_offset.tv_usec < 0) { 638 clock_offset.tv_sec--; 639 clock_offset.tv_usec += 1000000; 640 } 641 time.tv_usec += clock_cpu; 642 clock_cpu = 0; 643 #else 644 time.tv_usec += time_update; 645 #endif /* HIGHBALL */ 646 647 /* 648 * On rollover of the second the phase adjustment to be used for 649 * the next second is calculated. Also, the maximum error is 650 * increased by the tolerance. If the PPS frequency discipline 651 * code is present, the phase is increased to compensate for the 652 * CPU clock oscillator frequency error. 653 * 654 * On a 32-bit machine and given parameters in the timex.h 655 * header file, the maximum phase adjustment is +-512 ms and 656 * maximum frequency offset is a tad less than) +-512 ppm. On a 657 * 64-bit machine, you shouldn't need to ask. 658 */ 659 if (time.tv_usec >= 1000000) { 660 time.tv_usec -= 1000000; 661 time.tv_sec++; 662 time_maxerror += time_tolerance >> SHIFT_USEC; 663 664 /* 665 * Leap second processing. If in leap-insert state at 666 * the end of the day, the system clock is set back one 667 * second; if in leap-delete state, the system clock is 668 * set ahead one second. The microtime() routine or 669 * external clock driver will insure that reported time 670 * is always monotonic. The ugly divides should be 671 * replaced. 672 */ 673 switch (time_state) { 674 case TIME_OK: 675 if (time_status & STA_INS) 676 time_state = TIME_INS; 677 else if (time_status & STA_DEL) 678 time_state = TIME_DEL; 679 break; 680 681 case TIME_INS: 682 if (time.tv_sec % 86400 == 0) { 683 time.tv_sec--; 684 time_state = TIME_OOP; 685 } 686 break; 687 688 case TIME_DEL: 689 if ((time.tv_sec + 1) % 86400 == 0) { 690 time.tv_sec++; 691 time_state = TIME_WAIT; 692 } 693 break; 694 695 case TIME_OOP: 696 time_state = TIME_WAIT; 697 break; 698 699 case TIME_WAIT: 700 if (!(time_status & (STA_INS | STA_DEL))) 701 time_state = TIME_OK; 702 break; 703 } 704 705 /* 706 * Compute the phase adjustment for the next second. In 707 * PLL mode, the offset is reduced by a fixed factor 708 * times the time constant. In FLL mode the offset is 709 * used directly. In either mode, the maximum phase 710 * adjustment for each second is clamped so as to spread 711 * the adjustment over not more than the number of 712 * seconds between updates. 713 */ 714 if (time_offset < 0) { 715 ltemp = -time_offset; 716 if (!(time_status & STA_FLL)) 717 ltemp >>= SHIFT_KG + time_constant; 718 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 719 ltemp = (MAXPHASE / MINSEC) << 720 SHIFT_UPDATE; 721 time_offset += ltemp; 722 time_adj = -ltemp << (shifthz - SHIFT_UPDATE); 723 } else if (time_offset > 0) { 724 ltemp = time_offset; 725 if (!(time_status & STA_FLL)) 726 ltemp >>= SHIFT_KG + time_constant; 727 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 728 ltemp = (MAXPHASE / MINSEC) << 729 SHIFT_UPDATE; 730 time_offset -= ltemp; 731 time_adj = ltemp << (shifthz - SHIFT_UPDATE); 732 } else 733 time_adj = 0; 734 735 /* 736 * Compute the frequency estimate and additional phase 737 * adjustment due to frequency error for the next 738 * second. When the PPS signal is engaged, gnaw on the 739 * watchdog counter and update the frequency computed by 740 * the pll and the PPS signal. 741 */ 742 #ifdef PPS_SYNC 743 pps_valid++; 744 if (pps_valid == PPS_VALID) { 745 pps_jitter = MAXTIME; 746 pps_stabil = MAXFREQ; 747 time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | 748 STA_PPSWANDER | STA_PPSERROR); 749 } 750 ltemp = time_freq + pps_freq; 751 #else 752 ltemp = time_freq; 753 #endif /* PPS_SYNC */ 754 755 if (ltemp < 0) 756 time_adj -= -ltemp >> (SHIFT_USEC - shifthz); 757 else 758 time_adj += ltemp >> (SHIFT_USEC - shifthz); 759 time_adj += (long)fixtick << shifthz; 760 761 /* 762 * When the CPU clock oscillator frequency is not a 763 * power of 2 in Hz, shifthz is only an approximate 764 * scale factor. 765 * 766 * To determine the adjustment, you can do the following: 767 * bc -q 768 * scale=24 769 * obase=2 770 * idealhz/realhz 771 * where `idealhz' is the next higher power of 2, and `realhz' 772 * is the actual value. You may need to factor this result 773 * into a sequence of 2 multipliers to get better precision. 774 * 775 * Likewise, the error can be calculated with (e.g. for 100Hz): 776 * bc -q 777 * scale=24 778 * ((1+2^-2+2^-5)*(1-2^-10)*realhz-idealhz)/idealhz 779 * (and then multiply by 1000000 to get ppm). 780 */ 781 switch (hz) { 782 case 60: 783 /* A factor of 1.000100010001 gives about 15ppm 784 error. */ 785 if (time_adj < 0) { 786 time_adj -= (-time_adj >> 4); 787 time_adj -= (-time_adj >> 8); 788 } else { 789 time_adj += (time_adj >> 4); 790 time_adj += (time_adj >> 8); 791 } 792 break; 793 794 case 96: 795 /* A factor of 1.0101010101 gives about 244ppm error. */ 796 if (time_adj < 0) { 797 time_adj -= (-time_adj >> 2); 798 time_adj -= (-time_adj >> 4) + (-time_adj >> 8); 799 } else { 800 time_adj += (time_adj >> 2); 801 time_adj += (time_adj >> 4) + (time_adj >> 8); 802 } 803 break; 804 805 case 100: 806 /* A factor of 1.010001111010111 gives about 1ppm 807 error. */ 808 if (time_adj < 0) { 809 time_adj -= (-time_adj >> 2) + (-time_adj >> 5); 810 time_adj += (-time_adj >> 10); 811 } else { 812 time_adj += (time_adj >> 2) + (time_adj >> 5); 813 time_adj -= (time_adj >> 10); 814 } 815 break; 816 817 case 1000: 818 /* A factor of 1.000001100010100001 gives about 50ppm 819 error. */ 820 if (time_adj < 0) { 821 time_adj -= (-time_adj >> 6) + (-time_adj >> 11); 822 time_adj -= (-time_adj >> 7); 823 } else { 824 time_adj += (time_adj >> 6) + (time_adj >> 11); 825 time_adj += (time_adj >> 7); 826 } 827 break; 828 829 case 1200: 830 /* A factor of 1.1011010011100001 gives about 64ppm 831 error. */ 832 if (time_adj < 0) { 833 time_adj -= (-time_adj >> 1) + (-time_adj >> 6); 834 time_adj -= (-time_adj >> 3) + (-time_adj >> 10); 835 } else { 836 time_adj += (time_adj >> 1) + (time_adj >> 6); 837 time_adj += (time_adj >> 3) + (time_adj >> 10); 838 } 839 break; 840 } 841 842 #ifdef EXT_CLOCK 843 /* 844 * If an external clock is present, it is necessary to 845 * discipline the kernel time variable anyway, since not 846 * all system components use the microtime() interface. 847 * Here, the time offset between the external clock and 848 * kernel time variable is computed every so often. 849 */ 850 clock_count++; 851 if (clock_count > CLOCK_INTERVAL) { 852 clock_count = 0; 853 microtime(&clock_ext); 854 delta.tv_sec = clock_ext.tv_sec - time.tv_sec; 855 delta.tv_usec = clock_ext.tv_usec - 856 time.tv_usec; 857 if (delta.tv_usec < 0) 858 delta.tv_sec--; 859 if (delta.tv_usec >= 500000) { 860 delta.tv_usec -= 1000000; 861 delta.tv_sec++; 862 } 863 if (delta.tv_usec < -500000) { 864 delta.tv_usec += 1000000; 865 delta.tv_sec--; 866 } 867 if (delta.tv_sec > 0 || (delta.tv_sec == 0 && 868 delta.tv_usec > MAXPHASE) || 869 delta.tv_sec < -1 || (delta.tv_sec == -1 && 870 delta.tv_usec < -MAXPHASE)) { 871 time = clock_ext; 872 delta.tv_sec = 0; 873 delta.tv_usec = 0; 874 } 875 #ifdef HIGHBALL 876 clock_cpu = delta.tv_usec; 877 #else /* HIGHBALL */ 878 hardupdate(delta.tv_usec); 879 #endif /* HIGHBALL */ 880 } 881 #endif /* EXT_CLOCK */ 882 } 883 884 #endif /* NTP */ 885 886 /* 887 * Process callouts at a very low cpu priority, so we don't keep the 888 * relatively high clock interrupt priority any longer than necessary. 889 */ 890 simple_lock(&callwheel_slock); /* already at splclock() */ 891 hardclock_ticks++; 892 if (! TAILQ_EMPTY(&callwheel[hardclock_ticks & callwheelmask].cq_q)) { 893 simple_unlock(&callwheel_slock); 894 if (CLKF_BASEPRI(frame)) { 895 /* 896 * Save the overhead of a software interrupt; 897 * it will happen as soon as we return, so do 898 * it now. 899 * 900 * NOTE: If we're at ``base priority'', softclock() 901 * was not already running. 902 */ 903 spllowersoftclock(); 904 KERNEL_LOCK(LK_CANRECURSE|LK_EXCLUSIVE); 905 softclock(NULL); 906 KERNEL_UNLOCK(); 907 } else { 908 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 909 softintr_schedule(softclock_si); 910 #else 911 setsoftclock(); 912 #endif 913 } 914 return; 915 } else if (softclock_running == 0 && 916 (softclock_ticks + 1) == hardclock_ticks) { 917 softclock_ticks++; 918 } 919 simple_unlock(&callwheel_slock); 920 } 921 922 /* 923 * Software (low priority) clock interrupt. 924 * Run periodic events from timeout queue. 925 */ 926 /*ARGSUSED*/ 927 void 928 softclock(void *v) 929 { 930 struct callout_queue *bucket; 931 struct callout *c; 932 void (*func)(void *); 933 void *arg; 934 int s, idx; 935 int steps = 0; 936 937 CALLWHEEL_LOCK(s); 938 939 softclock_running = 1; 940 941 #ifdef CALLWHEEL_STATS 942 callwheel_softclocks.ev_count++; 943 #endif 944 945 while (softclock_ticks != hardclock_ticks) { 946 softclock_ticks++; 947 idx = (int)(softclock_ticks & callwheelmask); 948 bucket = &callwheel[idx]; 949 c = TAILQ_FIRST(&bucket->cq_q); 950 if (c == NULL) { 951 #ifdef CALLWHEEL_STATS 952 callwheel_softempty.ev_count++; 953 #endif 954 continue; 955 } 956 if (softclock_ticks < bucket->cq_hint) { 957 #ifdef CALLWHEEL_STATS 958 callwheel_hintworked.ev_count++; 959 #endif 960 continue; 961 } 962 bucket->cq_hint = UQUAD_MAX; 963 while (c != NULL) { 964 #ifdef CALLWHEEL_STATS 965 callwheel_softchecks.ev_count++; 966 #endif 967 if (c->c_time != softclock_ticks) { 968 if (c->c_time < bucket->cq_hint) 969 bucket->cq_hint = c->c_time; 970 c = TAILQ_NEXT(c, c_link); 971 if (++steps >= MAX_SOFTCLOCK_STEPS) { 972 nextsoftcheck = c; 973 /* Give interrupts a chance. */ 974 CALLWHEEL_UNLOCK(s); 975 CALLWHEEL_LOCK(s); 976 c = nextsoftcheck; 977 steps = 0; 978 } 979 } else { 980 nextsoftcheck = TAILQ_NEXT(c, c_link); 981 TAILQ_REMOVE(&bucket->cq_q, c, c_link); 982 #ifdef CALLWHEEL_STATS 983 callwheel_sizes[idx]--; 984 callwheel_fired.ev_count++; 985 callwheel_count.ev_count--; 986 #endif 987 func = c->c_func; 988 arg = c->c_arg; 989 c->c_func = NULL; 990 c->c_flags &= ~CALLOUT_PENDING; 991 CALLWHEEL_UNLOCK(s); 992 (*func)(arg); 993 CALLWHEEL_LOCK(s); 994 steps = 0; 995 c = nextsoftcheck; 996 } 997 } 998 if (TAILQ_EMPTY(&bucket->cq_q)) 999 bucket->cq_hint = UQUAD_MAX; 1000 } 1001 nextsoftcheck = NULL; 1002 softclock_running = 0; 1003 CALLWHEEL_UNLOCK(s); 1004 } 1005 1006 /* 1007 * callout_setsize: 1008 * 1009 * Determine how many callwheels are necessary and 1010 * set hash mask. Called from allocsys(). 1011 */ 1012 void 1013 callout_setsize(void) 1014 { 1015 1016 for (callwheelsize = 1; callwheelsize < ncallout; callwheelsize <<= 1) 1017 /* loop */ ; 1018 callwheelmask = callwheelsize - 1; 1019 } 1020 1021 /* 1022 * callout_startup: 1023 * 1024 * Initialize the callwheel buckets. 1025 */ 1026 void 1027 callout_startup(void) 1028 { 1029 int i; 1030 1031 for (i = 0; i < callwheelsize; i++) { 1032 callwheel[i].cq_hint = UQUAD_MAX; 1033 TAILQ_INIT(&callwheel[i].cq_q); 1034 } 1035 1036 simple_lock_init(&callwheel_slock); 1037 1038 #ifdef CALLWHEEL_STATS 1039 evcnt_attach_dynamic(&callwheel_collisions, EVCNT_TYPE_MISC, 1040 NULL, "callwheel", "collisions"); 1041 evcnt_attach_dynamic(&callwheel_maxlength, EVCNT_TYPE_MISC, 1042 NULL, "callwheel", "maxlength"); 1043 evcnt_attach_dynamic(&callwheel_count, EVCNT_TYPE_MISC, 1044 NULL, "callwheel", "count"); 1045 evcnt_attach_dynamic(&callwheel_established, EVCNT_TYPE_MISC, 1046 NULL, "callwheel", "established"); 1047 evcnt_attach_dynamic(&callwheel_fired, EVCNT_TYPE_MISC, 1048 NULL, "callwheel", "fired"); 1049 evcnt_attach_dynamic(&callwheel_disestablished, EVCNT_TYPE_MISC, 1050 NULL, "callwheel", "disestablished"); 1051 evcnt_attach_dynamic(&callwheel_changed, EVCNT_TYPE_MISC, 1052 NULL, "callwheel", "changed"); 1053 evcnt_attach_dynamic(&callwheel_softclocks, EVCNT_TYPE_MISC, 1054 NULL, "callwheel", "softclocks"); 1055 evcnt_attach_dynamic(&callwheel_softempty, EVCNT_TYPE_MISC, 1056 NULL, "callwheel", "softempty"); 1057 evcnt_attach_dynamic(&callwheel_hintworked, EVCNT_TYPE_MISC, 1058 NULL, "callwheel", "hintworked"); 1059 #endif /* CALLWHEEL_STATS */ 1060 } 1061 1062 /* 1063 * callout_init: 1064 * 1065 * Initialize a callout structure so that it can be used 1066 * by callout_reset() and callout_stop(). 1067 */ 1068 void 1069 callout_init(struct callout *c) 1070 { 1071 1072 memset(c, 0, sizeof(*c)); 1073 } 1074 1075 /* 1076 * callout_reset: 1077 * 1078 * Establish or change a timeout. 1079 */ 1080 void 1081 callout_reset(struct callout *c, int ticks, void (*func)(void *), void *arg) 1082 { 1083 struct callout_queue *bucket; 1084 int s; 1085 1086 if (ticks <= 0) 1087 ticks = 1; 1088 1089 CALLWHEEL_LOCK(s); 1090 1091 /* 1092 * If this callout's timer is already running, cancel it 1093 * before we modify it. 1094 */ 1095 if (c->c_flags & CALLOUT_PENDING) { 1096 callout_stop_locked(c); /* Already locked */ 1097 #ifdef CALLWHEEL_STATS 1098 callwheel_changed.ev_count++; 1099 #endif 1100 } 1101 1102 c->c_arg = arg; 1103 c->c_func = func; 1104 c->c_flags = CALLOUT_ACTIVE | CALLOUT_PENDING; 1105 c->c_time = hardclock_ticks + ticks; 1106 1107 bucket = &callwheel[c->c_time & callwheelmask]; 1108 1109 #ifdef CALLWHEEL_STATS 1110 if (! TAILQ_EMPTY(&bucket->cq_q)) 1111 callwheel_collisions.ev_count++; 1112 #endif 1113 1114 TAILQ_INSERT_TAIL(&bucket->cq_q, c, c_link); 1115 if (c->c_time < bucket->cq_hint) 1116 bucket->cq_hint = c->c_time; 1117 1118 #ifdef CALLWHEEL_STATS 1119 callwheel_count.ev_count++; 1120 callwheel_established.ev_count++; 1121 if (++callwheel_sizes[c->c_time & callwheelmask] > 1122 callwheel_maxlength.ev_count) 1123 callwheel_maxlength.ev_count = 1124 callwheel_sizes[c->c_time & callwheelmask]; 1125 #endif 1126 1127 CALLWHEEL_UNLOCK(s); 1128 } 1129 1130 /* 1131 * callout_stop_locked: 1132 * 1133 * Disestablish a timeout. Callwheel is locked. 1134 */ 1135 static void 1136 callout_stop_locked(struct callout *c) 1137 { 1138 struct callout_queue *bucket; 1139 1140 /* 1141 * Don't attempt to delete a callout that's not on the queue. 1142 */ 1143 if ((c->c_flags & CALLOUT_PENDING) == 0) { 1144 c->c_flags &= ~CALLOUT_ACTIVE; 1145 return; 1146 } 1147 1148 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 1149 1150 if (nextsoftcheck == c) 1151 nextsoftcheck = TAILQ_NEXT(c, c_link); 1152 1153 bucket = &callwheel[c->c_time & callwheelmask]; 1154 TAILQ_REMOVE(&bucket->cq_q, c, c_link); 1155 if (TAILQ_EMPTY(&bucket->cq_q)) 1156 bucket->cq_hint = UQUAD_MAX; 1157 #ifdef CALLWHEEL_STATS 1158 callwheel_count.ev_count--; 1159 callwheel_disestablished.ev_count++; 1160 callwheel_sizes[c->c_time & callwheelmask]--; 1161 #endif 1162 1163 c->c_func = NULL; 1164 } 1165 1166 /* 1167 * callout_stop: 1168 * 1169 * Disestablish a timeout. Callwheel is unlocked. This is 1170 * the standard entry point. 1171 */ 1172 void 1173 callout_stop(struct callout *c) 1174 { 1175 int s; 1176 1177 CALLWHEEL_LOCK(s); 1178 callout_stop_locked(c); 1179 CALLWHEEL_UNLOCK(s); 1180 } 1181 1182 #ifdef CALLWHEEL_STATS 1183 /* 1184 * callout_showstats: 1185 * 1186 * Display callout statistics. Call it from DDB. 1187 */ 1188 void 1189 callout_showstats(void) 1190 { 1191 u_int64_t curticks; 1192 int s; 1193 1194 s = splclock(); 1195 curticks = softclock_ticks; 1196 splx(s); 1197 1198 printf("Callwheel statistics:\n"); 1199 printf("\tCallouts currently queued: %llu\n", 1200 (long long) callwheel_count.ev_count); 1201 printf("\tCallouts established: %llu\n", 1202 (long long) callwheel_established.ev_count); 1203 printf("\tCallouts disestablished: %llu\n", 1204 (long long) callwheel_disestablished.ev_count); 1205 if (callwheel_changed.ev_count != 0) 1206 printf("\t\tOf those, %llu were changes\n", 1207 (long long) callwheel_changed.ev_count); 1208 printf("\tCallouts that fired: %llu\n", 1209 (long long) callwheel_fired.ev_count); 1210 printf("\tNumber of buckets: %d\n", callwheelsize); 1211 printf("\tNumber of hash collisions: %llu\n", 1212 (long long) callwheel_collisions.ev_count); 1213 printf("\tMaximum hash chain length: %llu\n", 1214 (long long) callwheel_maxlength.ev_count); 1215 printf("\tSoftclocks: %llu, Softchecks: %llu\n", 1216 (long long) callwheel_softclocks.ev_count, 1217 (long long) callwheel_softchecks.ev_count); 1218 printf("\t\tEmpty buckets seen: %llu\n", 1219 (long long) callwheel_softempty.ev_count); 1220 printf("\t\tTimes hint saved scan: %llu\n", 1221 (long long) callwheel_hintworked.ev_count); 1222 } 1223 #endif 1224 1225 /* 1226 * Compute number of hz until specified time. Used to compute second 1227 * argument to callout_reset() from an absolute time. 1228 */ 1229 int 1230 hzto(struct timeval *tv) 1231 { 1232 unsigned long ticks; 1233 long sec, usec; 1234 int s; 1235 1236 /* 1237 * If the number of usecs in the whole seconds part of the time 1238 * difference fits in a long, then the total number of usecs will 1239 * fit in an unsigned long. Compute the total and convert it to 1240 * ticks, rounding up and adding 1 to allow for the current tick 1241 * to expire. Rounding also depends on unsigned long arithmetic 1242 * to avoid overflow. 1243 * 1244 * Otherwise, if the number of ticks in the whole seconds part of 1245 * the time difference fits in a long, then convert the parts to 1246 * ticks separately and add, using similar rounding methods and 1247 * overflow avoidance. This method would work in the previous 1248 * case, but it is slightly slower and assume that hz is integral. 1249 * 1250 * Otherwise, round the time difference down to the maximum 1251 * representable value. 1252 * 1253 * If ints are 32-bit, then the maximum value for any timeout in 1254 * 10ms ticks is 248 days. 1255 */ 1256 s = splclock(); 1257 sec = tv->tv_sec - time.tv_sec; 1258 usec = tv->tv_usec - time.tv_usec; 1259 splx(s); 1260 1261 if (usec < 0) { 1262 sec--; 1263 usec += 1000000; 1264 } 1265 1266 if (sec < 0 || (sec == 0 && usec <= 0)) { 1267 /* 1268 * Would expire now or in the past. Return 0 ticks. 1269 * This is different from the legacy hzto() interface, 1270 * and callers need to check for it. 1271 */ 1272 ticks = 0; 1273 } else if (sec <= (LONG_MAX / 1000000)) 1274 ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1)) 1275 / tick) + 1; 1276 else if (sec <= (LONG_MAX / hz)) 1277 ticks = (sec * hz) + 1278 (((unsigned long)usec + (tick - 1)) / tick) + 1; 1279 else 1280 ticks = LONG_MAX; 1281 1282 if (ticks > INT_MAX) 1283 ticks = INT_MAX; 1284 1285 return ((int)ticks); 1286 } 1287 1288 /* 1289 * Start profiling on a process. 1290 * 1291 * Kernel profiling passes proc0 which never exits and hence 1292 * keeps the profile clock running constantly. 1293 */ 1294 void 1295 startprofclock(struct proc *p) 1296 { 1297 1298 if ((p->p_flag & P_PROFIL) == 0) { 1299 p->p_flag |= P_PROFIL; 1300 if (++profprocs == 1 && stathz != 0) 1301 psdiv = psratio; 1302 } 1303 } 1304 1305 /* 1306 * Stop profiling on a process. 1307 */ 1308 void 1309 stopprofclock(struct proc *p) 1310 { 1311 1312 if (p->p_flag & P_PROFIL) { 1313 p->p_flag &= ~P_PROFIL; 1314 if (--profprocs == 0 && stathz != 0) 1315 psdiv = 1; 1316 } 1317 } 1318 1319 /* 1320 * Statistics clock. Grab profile sample, and if divider reaches 0, 1321 * do process and kernel statistics. 1322 */ 1323 void 1324 statclock(struct clockframe *frame) 1325 { 1326 #ifdef GPROF 1327 struct gmonparam *g; 1328 intptr_t i; 1329 #endif 1330 struct cpu_info *ci = curcpu(); 1331 struct schedstate_percpu *spc = &ci->ci_schedstate; 1332 struct proc *p; 1333 1334 /* 1335 * Notice changes in divisor frequency, and adjust clock 1336 * frequency accordingly. 1337 */ 1338 if (spc->spc_psdiv != psdiv) { 1339 spc->spc_psdiv = psdiv; 1340 spc->spc_pscnt = psdiv; 1341 if (psdiv == 1) { 1342 setstatclockrate(stathz); 1343 } else { 1344 setstatclockrate(profhz); 1345 } 1346 } 1347 p = curproc; 1348 if (CLKF_USERMODE(frame)) { 1349 if (p->p_flag & P_PROFIL) 1350 addupc_intr(p, CLKF_PC(frame)); 1351 if (--spc->spc_pscnt > 0) 1352 return; 1353 /* 1354 * Came from user mode; CPU was in user state. 1355 * If this process is being profiled record the tick. 1356 */ 1357 p->p_uticks++; 1358 if (p->p_nice > NZERO) 1359 spc->spc_cp_time[CP_NICE]++; 1360 else 1361 spc->spc_cp_time[CP_USER]++; 1362 } else { 1363 #ifdef GPROF 1364 /* 1365 * Kernel statistics are just like addupc_intr, only easier. 1366 */ 1367 g = &_gmonparam; 1368 if (g->state == GMON_PROF_ON) { 1369 i = CLKF_PC(frame) - g->lowpc; 1370 if (i < g->textsize) { 1371 i /= HISTFRACTION * sizeof(*g->kcount); 1372 g->kcount[i]++; 1373 } 1374 } 1375 #endif 1376 #ifdef PROC_PC 1377 if (p && p->p_flag & P_PROFIL) 1378 addupc_intr(p, PROC_PC(p)); 1379 #endif 1380 if (--spc->spc_pscnt > 0) 1381 return; 1382 /* 1383 * Came from kernel mode, so we were: 1384 * - handling an interrupt, 1385 * - doing syscall or trap work on behalf of the current 1386 * user process, or 1387 * - spinning in the idle loop. 1388 * Whichever it is, charge the time as appropriate. 1389 * Note that we charge interrupts to the current process, 1390 * regardless of whether they are ``for'' that process, 1391 * so that we know how much of its real time was spent 1392 * in ``non-process'' (i.e., interrupt) work. 1393 */ 1394 if (CLKF_INTR(frame)) { 1395 if (p != NULL) 1396 p->p_iticks++; 1397 spc->spc_cp_time[CP_INTR]++; 1398 } else if (p != NULL) { 1399 p->p_sticks++; 1400 spc->spc_cp_time[CP_SYS]++; 1401 } else 1402 spc->spc_cp_time[CP_IDLE]++; 1403 } 1404 spc->spc_pscnt = psdiv; 1405 1406 if (p != NULL) { 1407 ++p->p_cpticks; 1408 /* 1409 * If no separate schedclock is provided, call it here 1410 * at ~~12-25 Hz, ~~16 Hz is best 1411 */ 1412 if (schedhz == 0) 1413 if ((++ci->ci_schedstate.spc_schedticks & 3) == 0) 1414 schedclock(p); 1415 } 1416 } 1417 1418 1419 #ifdef NTP /* NTP phase-locked loop in kernel */ 1420 1421 /* 1422 * hardupdate() - local clock update 1423 * 1424 * This routine is called by ntp_adjtime() to update the local clock 1425 * phase and frequency. The implementation is of an adaptive-parameter, 1426 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 1427 * time and frequency offset estimates for each call. If the kernel PPS 1428 * discipline code is configured (PPS_SYNC), the PPS signal itself 1429 * determines the new time offset, instead of the calling argument. 1430 * Presumably, calls to ntp_adjtime() occur only when the caller 1431 * believes the local clock is valid within some bound (+-128 ms with 1432 * NTP). If the caller's time is far different than the PPS time, an 1433 * argument will ensue, and it's not clear who will lose. 1434 * 1435 * For uncompensated quartz crystal oscillatores and nominal update 1436 * intervals less than 1024 s, operation should be in phase-lock mode 1437 * (STA_FLL = 0), where the loop is disciplined to phase. For update 1438 * intervals greater than thiss, operation should be in frequency-lock 1439 * mode (STA_FLL = 1), where the loop is disciplined to frequency. 1440 * 1441 * Note: splclock() is in effect. 1442 */ 1443 void 1444 hardupdate(long offset) 1445 { 1446 long ltemp, mtemp; 1447 1448 if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME)) 1449 return; 1450 ltemp = offset; 1451 #ifdef PPS_SYNC 1452 if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL) 1453 ltemp = pps_offset; 1454 #endif /* PPS_SYNC */ 1455 1456 /* 1457 * Scale the phase adjustment and clamp to the operating range. 1458 */ 1459 if (ltemp > MAXPHASE) 1460 time_offset = MAXPHASE << SHIFT_UPDATE; 1461 else if (ltemp < -MAXPHASE) 1462 time_offset = -(MAXPHASE << SHIFT_UPDATE); 1463 else 1464 time_offset = ltemp << SHIFT_UPDATE; 1465 1466 /* 1467 * Select whether the frequency is to be controlled and in which 1468 * mode (PLL or FLL). Clamp to the operating range. Ugly 1469 * multiply/divide should be replaced someday. 1470 */ 1471 if (time_status & STA_FREQHOLD || time_reftime == 0) 1472 time_reftime = time.tv_sec; 1473 mtemp = time.tv_sec - time_reftime; 1474 time_reftime = time.tv_sec; 1475 if (time_status & STA_FLL) { 1476 if (mtemp >= MINSEC) { 1477 ltemp = ((time_offset / mtemp) << (SHIFT_USEC - 1478 SHIFT_UPDATE)); 1479 if (ltemp < 0) 1480 time_freq -= -ltemp >> SHIFT_KH; 1481 else 1482 time_freq += ltemp >> SHIFT_KH; 1483 } 1484 } else { 1485 if (mtemp < MAXSEC) { 1486 ltemp *= mtemp; 1487 if (ltemp < 0) 1488 time_freq -= -ltemp >> (time_constant + 1489 time_constant + SHIFT_KF - 1490 SHIFT_USEC); 1491 else 1492 time_freq += ltemp >> (time_constant + 1493 time_constant + SHIFT_KF - 1494 SHIFT_USEC); 1495 } 1496 } 1497 if (time_freq > time_tolerance) 1498 time_freq = time_tolerance; 1499 else if (time_freq < -time_tolerance) 1500 time_freq = -time_tolerance; 1501 } 1502 1503 #ifdef PPS_SYNC 1504 /* 1505 * hardpps() - discipline CPU clock oscillator to external PPS signal 1506 * 1507 * This routine is called at each PPS interrupt in order to discipline 1508 * the CPU clock oscillator to the PPS signal. It measures the PPS phase 1509 * and leaves it in a handy spot for the hardclock() routine. It 1510 * integrates successive PPS phase differences and calculates the 1511 * frequency offset. This is used in hardclock() to discipline the CPU 1512 * clock oscillator so that intrinsic frequency error is cancelled out. 1513 * The code requires the caller to capture the time and hardware counter 1514 * value at the on-time PPS signal transition. 1515 * 1516 * Note that, on some Unix systems, this routine runs at an interrupt 1517 * priority level higher than the timer interrupt routine hardclock(). 1518 * Therefore, the variables used are distinct from the hardclock() 1519 * variables, except for certain exceptions: The PPS frequency pps_freq 1520 * and phase pps_offset variables are determined by this routine and 1521 * updated atomically. The time_tolerance variable can be considered a 1522 * constant, since it is infrequently changed, and then only when the 1523 * PPS signal is disabled. The watchdog counter pps_valid is updated 1524 * once per second by hardclock() and is atomically cleared in this 1525 * routine. 1526 */ 1527 void 1528 hardpps(struct timeval *tvp, /* time at PPS */ 1529 long usec /* hardware counter at PPS */) 1530 { 1531 long u_usec, v_usec, bigtick; 1532 long cal_sec, cal_usec; 1533 1534 /* 1535 * An occasional glitch can be produced when the PPS interrupt 1536 * occurs in the hardclock() routine before the time variable is 1537 * updated. Here the offset is discarded when the difference 1538 * between it and the last one is greater than tick/2, but not 1539 * if the interval since the first discard exceeds 30 s. 1540 */ 1541 time_status |= STA_PPSSIGNAL; 1542 time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); 1543 pps_valid = 0; 1544 u_usec = -tvp->tv_usec; 1545 if (u_usec < -500000) 1546 u_usec += 1000000; 1547 v_usec = pps_offset - u_usec; 1548 if (v_usec < 0) 1549 v_usec = -v_usec; 1550 if (v_usec > (tick >> 1)) { 1551 if (pps_glitch > MAXGLITCH) { 1552 pps_glitch = 0; 1553 pps_tf[2] = u_usec; 1554 pps_tf[1] = u_usec; 1555 } else { 1556 pps_glitch++; 1557 u_usec = pps_offset; 1558 } 1559 } else 1560 pps_glitch = 0; 1561 1562 /* 1563 * A three-stage median filter is used to help deglitch the pps 1564 * time. The median sample becomes the time offset estimate; the 1565 * difference between the other two samples becomes the time 1566 * dispersion (jitter) estimate. 1567 */ 1568 pps_tf[2] = pps_tf[1]; 1569 pps_tf[1] = pps_tf[0]; 1570 pps_tf[0] = u_usec; 1571 if (pps_tf[0] > pps_tf[1]) { 1572 if (pps_tf[1] > pps_tf[2]) { 1573 pps_offset = pps_tf[1]; /* 0 1 2 */ 1574 v_usec = pps_tf[0] - pps_tf[2]; 1575 } else if (pps_tf[2] > pps_tf[0]) { 1576 pps_offset = pps_tf[0]; /* 2 0 1 */ 1577 v_usec = pps_tf[2] - pps_tf[1]; 1578 } else { 1579 pps_offset = pps_tf[2]; /* 0 2 1 */ 1580 v_usec = pps_tf[0] - pps_tf[1]; 1581 } 1582 } else { 1583 if (pps_tf[1] < pps_tf[2]) { 1584 pps_offset = pps_tf[1]; /* 2 1 0 */ 1585 v_usec = pps_tf[2] - pps_tf[0]; 1586 } else if (pps_tf[2] < pps_tf[0]) { 1587 pps_offset = pps_tf[0]; /* 1 0 2 */ 1588 v_usec = pps_tf[1] - pps_tf[2]; 1589 } else { 1590 pps_offset = pps_tf[2]; /* 1 2 0 */ 1591 v_usec = pps_tf[1] - pps_tf[0]; 1592 } 1593 } 1594 if (v_usec > MAXTIME) 1595 pps_jitcnt++; 1596 v_usec = (v_usec << PPS_AVG) - pps_jitter; 1597 if (v_usec < 0) 1598 pps_jitter -= -v_usec >> PPS_AVG; 1599 else 1600 pps_jitter += v_usec >> PPS_AVG; 1601 if (pps_jitter > (MAXTIME >> 1)) 1602 time_status |= STA_PPSJITTER; 1603 1604 /* 1605 * During the calibration interval adjust the starting time when 1606 * the tick overflows. At the end of the interval compute the 1607 * duration of the interval and the difference of the hardware 1608 * counters at the beginning and end of the interval. This code 1609 * is deliciously complicated by the fact valid differences may 1610 * exceed the value of tick when using long calibration 1611 * intervals and small ticks. Note that the counter can be 1612 * greater than tick if caught at just the wrong instant, but 1613 * the values returned and used here are correct. 1614 */ 1615 bigtick = (long)tick << SHIFT_USEC; 1616 pps_usec -= pps_freq; 1617 if (pps_usec >= bigtick) 1618 pps_usec -= bigtick; 1619 if (pps_usec < 0) 1620 pps_usec += bigtick; 1621 pps_time.tv_sec++; 1622 pps_count++; 1623 if (pps_count < (1 << pps_shift)) 1624 return; 1625 pps_count = 0; 1626 pps_calcnt++; 1627 u_usec = usec << SHIFT_USEC; 1628 v_usec = pps_usec - u_usec; 1629 if (v_usec >= bigtick >> 1) 1630 v_usec -= bigtick; 1631 if (v_usec < -(bigtick >> 1)) 1632 v_usec += bigtick; 1633 if (v_usec < 0) 1634 v_usec = -(-v_usec >> pps_shift); 1635 else 1636 v_usec = v_usec >> pps_shift; 1637 pps_usec = u_usec; 1638 cal_sec = tvp->tv_sec; 1639 cal_usec = tvp->tv_usec; 1640 cal_sec -= pps_time.tv_sec; 1641 cal_usec -= pps_time.tv_usec; 1642 if (cal_usec < 0) { 1643 cal_usec += 1000000; 1644 cal_sec--; 1645 } 1646 pps_time = *tvp; 1647 1648 /* 1649 * Check for lost interrupts, noise, excessive jitter and 1650 * excessive frequency error. The number of timer ticks during 1651 * the interval may vary +-1 tick. Add to this a margin of one 1652 * tick for the PPS signal jitter and maximum frequency 1653 * deviation. If the limits are exceeded, the calibration 1654 * interval is reset to the minimum and we start over. 1655 */ 1656 u_usec = (long)tick << 1; 1657 if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec)) 1658 || (cal_sec == 0 && cal_usec < u_usec)) 1659 || v_usec > time_tolerance || v_usec < -time_tolerance) { 1660 pps_errcnt++; 1661 pps_shift = PPS_SHIFT; 1662 pps_intcnt = 0; 1663 time_status |= STA_PPSERROR; 1664 return; 1665 } 1666 1667 /* 1668 * A three-stage median filter is used to help deglitch the pps 1669 * frequency. The median sample becomes the frequency offset 1670 * estimate; the difference between the other two samples 1671 * becomes the frequency dispersion (stability) estimate. 1672 */ 1673 pps_ff[2] = pps_ff[1]; 1674 pps_ff[1] = pps_ff[0]; 1675 pps_ff[0] = v_usec; 1676 if (pps_ff[0] > pps_ff[1]) { 1677 if (pps_ff[1] > pps_ff[2]) { 1678 u_usec = pps_ff[1]; /* 0 1 2 */ 1679 v_usec = pps_ff[0] - pps_ff[2]; 1680 } else if (pps_ff[2] > pps_ff[0]) { 1681 u_usec = pps_ff[0]; /* 2 0 1 */ 1682 v_usec = pps_ff[2] - pps_ff[1]; 1683 } else { 1684 u_usec = pps_ff[2]; /* 0 2 1 */ 1685 v_usec = pps_ff[0] - pps_ff[1]; 1686 } 1687 } else { 1688 if (pps_ff[1] < pps_ff[2]) { 1689 u_usec = pps_ff[1]; /* 2 1 0 */ 1690 v_usec = pps_ff[2] - pps_ff[0]; 1691 } else if (pps_ff[2] < pps_ff[0]) { 1692 u_usec = pps_ff[0]; /* 1 0 2 */ 1693 v_usec = pps_ff[1] - pps_ff[2]; 1694 } else { 1695 u_usec = pps_ff[2]; /* 1 2 0 */ 1696 v_usec = pps_ff[1] - pps_ff[0]; 1697 } 1698 } 1699 1700 /* 1701 * Here the frequency dispersion (stability) is updated. If it 1702 * is less than one-fourth the maximum (MAXFREQ), the frequency 1703 * offset is updated as well, but clamped to the tolerance. It 1704 * will be processed later by the hardclock() routine. 1705 */ 1706 v_usec = (v_usec >> 1) - pps_stabil; 1707 if (v_usec < 0) 1708 pps_stabil -= -v_usec >> PPS_AVG; 1709 else 1710 pps_stabil += v_usec >> PPS_AVG; 1711 if (pps_stabil > MAXFREQ >> 2) { 1712 pps_stbcnt++; 1713 time_status |= STA_PPSWANDER; 1714 return; 1715 } 1716 if (time_status & STA_PPSFREQ) { 1717 if (u_usec < 0) { 1718 pps_freq -= -u_usec >> PPS_AVG; 1719 if (pps_freq < -time_tolerance) 1720 pps_freq = -time_tolerance; 1721 u_usec = -u_usec; 1722 } else { 1723 pps_freq += u_usec >> PPS_AVG; 1724 if (pps_freq > time_tolerance) 1725 pps_freq = time_tolerance; 1726 } 1727 } 1728 1729 /* 1730 * Here the calibration interval is adjusted. If the maximum 1731 * time difference is greater than tick / 4, reduce the interval 1732 * by half. If this is not the case for four consecutive 1733 * intervals, double the interval. 1734 */ 1735 if (u_usec << pps_shift > bigtick >> 2) { 1736 pps_intcnt = 0; 1737 if (pps_shift > PPS_SHIFT) 1738 pps_shift--; 1739 } else if (pps_intcnt >= 4) { 1740 pps_intcnt = 0; 1741 if (pps_shift < PPS_SHIFTMAX) 1742 pps_shift++; 1743 } else 1744 pps_intcnt++; 1745 } 1746 #endif /* PPS_SYNC */ 1747 #endif /* NTP */ 1748 1749 /* 1750 * Return information about system clocks. 1751 */ 1752 int 1753 sysctl_clockrate(void *where, size_t *sizep) 1754 { 1755 struct clockinfo clkinfo; 1756 1757 /* 1758 * Construct clockinfo structure. 1759 */ 1760 clkinfo.tick = tick; 1761 clkinfo.tickadj = tickadj; 1762 clkinfo.hz = hz; 1763 clkinfo.profhz = profhz; 1764 clkinfo.stathz = stathz ? stathz : hz; 1765 return (sysctl_rdstruct(where, sizep, NULL, &clkinfo, sizeof(clkinfo))); 1766 } 1767