1 /* $OpenBSD: kern_clock.c,v 1.27 2000/08/23 20:36:18 art Exp $ */ 2 /* $NetBSD: kern_clock.c,v 1.34 1996/06/09 04:51:03 briggs Exp $ */ 3 4 /*- 5 * Copyright (c) 1982, 1986, 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. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/dkstat.h> 47 #include <sys/timeout.h> 48 #include <sys/kernel.h> 49 #include <sys/proc.h> 50 #include <sys/resourcevar.h> 51 #include <sys/signalvar.h> 52 #include <vm/vm.h> 53 #include <sys/sysctl.h> 54 #include <sys/timex.h> 55 #include <sys/sched.h> 56 57 #include <machine/cpu.h> 58 #include <machine/limits.h> 59 60 #ifdef GPROF 61 #include <sys/gmon.h> 62 #endif 63 64 /* 65 * Clock handling routines. 66 * 67 * This code is written to operate with two timers that run independently of 68 * each other. The main clock, running hz times per second, is used to keep 69 * track of real time. The second timer handles kernel and user profiling, 70 * and does resource use estimation. If the second timer is programmable, 71 * it is randomized to avoid aliasing between the two clocks. For example, 72 * the randomization prevents an adversary from always giving up the cpu 73 * just before its quantum expires. Otherwise, it would never accumulate 74 * cpu ticks. The mean frequency of the second timer is stathz. 75 * 76 * If no second timer exists, stathz will be zero; in this case we drive 77 * profiling and statistics off the main clock. This WILL NOT be accurate; 78 * do not do it unless absolutely necessary. 79 * 80 * The statistics clock may (or may not) be run at a higher rate while 81 * profiling. This profile clock runs at profhz. We require that profhz 82 * be an integral multiple of stathz. 83 * 84 * If the statistics clock is running fast, it must be divided by the ratio 85 * profhz/stathz for statistics. (For profiling, every tick counts.) 86 */ 87 88 /* 89 * TODO: 90 * allocate more timeout table slots when table overflows. 91 */ 92 93 94 #ifdef NTP /* NTP phase-locked loop in kernel */ 95 /* 96 * Phase/frequency-lock loop (PLL/FLL) definitions 97 * 98 * The following variables are read and set by the ntp_adjtime() system 99 * call. 100 * 101 * time_state shows the state of the system clock, with values defined 102 * in the timex.h header file. 103 * 104 * time_status shows the status of the system clock, with bits defined 105 * in the timex.h header file. 106 * 107 * time_offset is used by the PLL/FLL to adjust the system time in small 108 * increments. 109 * 110 * time_constant determines the bandwidth or "stiffness" of the PLL. 111 * 112 * time_tolerance determines maximum frequency error or tolerance of the 113 * CPU clock oscillator and is a property of the architecture; however, 114 * in principle it could change as result of the presence of external 115 * discipline signals, for instance. 116 * 117 * time_precision is usually equal to the kernel tick variable; however, 118 * in cases where a precision clock counter or external clock is 119 * available, the resolution can be much less than this and depend on 120 * whether the external clock is working or not. 121 * 122 * time_maxerror is initialized by a ntp_adjtime() call and increased by 123 * the kernel once each second to reflect the maximum error bound 124 * growth. 125 * 126 * time_esterror is set and read by the ntp_adjtime() call, but 127 * otherwise not used by the kernel. 128 */ 129 int time_state = TIME_OK; /* clock state */ 130 int time_status = STA_UNSYNC; /* clock status bits */ 131 long time_offset = 0; /* time offset (us) */ 132 long time_constant = 0; /* pll time constant */ 133 long time_tolerance = MAXFREQ; /* frequency tolerance (scaled ppm) */ 134 long time_precision; /* clock precision (us) */ 135 long time_maxerror = MAXPHASE; /* maximum error (us) */ 136 long time_esterror = MAXPHASE; /* estimated error (us) */ 137 138 /* 139 * The following variables establish the state of the PLL/FLL and the 140 * residual time and frequency offset of the local clock. The scale 141 * factors are defined in the timex.h header file. 142 * 143 * time_phase and time_freq are the phase increment and the frequency 144 * increment, respectively, of the kernel time variable. 145 * 146 * time_freq is set via ntp_adjtime() from a value stored in a file when 147 * the synchronization daemon is first started. Its value is retrieved 148 * via ntp_adjtime() and written to the file about once per hour by the 149 * daemon. 150 * 151 * time_adj is the adjustment added to the value of tick at each timer 152 * interrupt and is recomputed from time_phase and time_freq at each 153 * seconds rollover. 154 * 155 * time_reftime is the second's portion of the system time at the last 156 * call to ntp_adjtime(). It is used to adjust the time_freq variable 157 * and to increase the time_maxerror as the time since last update 158 * increases. 159 */ 160 long time_phase = 0; /* phase offset (scaled us) */ 161 long time_freq = 0; /* frequency offset (scaled ppm) */ 162 long time_adj = 0; /* tick adjust (scaled 1 / hz) */ 163 long time_reftime = 0; /* time at last adjustment (s) */ 164 165 #ifdef PPS_SYNC 166 /* 167 * The following variables are used only if the kernel PPS discipline 168 * code is configured (PPS_SYNC). The scale factors are defined in the 169 * timex.h header file. 170 * 171 * pps_time contains the time at each calibration interval, as read by 172 * microtime(). pps_count counts the seconds of the calibration 173 * interval, the duration of which is nominally pps_shift in powers of 174 * two. 175 * 176 * pps_offset is the time offset produced by the time median filter 177 * pps_tf[], while pps_jitter is the dispersion (jitter) measured by 178 * this filter. 179 * 180 * pps_freq is the frequency offset produced by the frequency median 181 * filter pps_ff[], while pps_stabil is the dispersion (wander) measured 182 * by this filter. 183 * 184 * pps_usec is latched from a high resolution counter or external clock 185 * at pps_time. Here we want the hardware counter contents only, not the 186 * contents plus the time_tv.usec as usual. 187 * 188 * pps_valid counts the number of seconds since the last PPS update. It 189 * is used as a watchdog timer to disable the PPS discipline should the 190 * PPS signal be lost. 191 * 192 * pps_glitch counts the number of seconds since the beginning of an 193 * offset burst more than tick/2 from current nominal offset. It is used 194 * mainly to suppress error bursts due to priority conflicts between the 195 * PPS interrupt and timer interrupt. 196 * 197 * pps_intcnt counts the calibration intervals for use in the interval- 198 * adaptation algorithm. It's just too complicated for words. 199 */ 200 struct timeval pps_time; /* kernel time at last interval */ 201 long pps_tf[] = {0, 0, 0}; /* pps time offset median filter (us) */ 202 long pps_offset = 0; /* pps time offset (us) */ 203 long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */ 204 long pps_ff[] = {0, 0, 0}; /* pps frequency offset median filter */ 205 long pps_freq = 0; /* frequency offset (scaled ppm) */ 206 long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */ 207 long pps_usec = 0; /* microsec counter at last interval */ 208 long pps_valid = PPS_VALID; /* pps signal watchdog counter */ 209 int pps_glitch = 0; /* pps signal glitch counter */ 210 int pps_count = 0; /* calibration interval counter (s) */ 211 int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */ 212 int pps_intcnt = 0; /* intervals at current duration */ 213 214 /* 215 * PPS signal quality monitors 216 * 217 * pps_jitcnt counts the seconds that have been discarded because the 218 * jitter measured by the time median filter exceeds the limit MAXTIME 219 * (100 us). 220 * 221 * pps_calcnt counts the frequency calibration intervals, which are 222 * variable from 4 s to 256 s. 223 * 224 * pps_errcnt counts the calibration intervals which have been discarded 225 * because the wander exceeds the limit MAXFREQ (100 ppm) or where the 226 * calibration interval jitter exceeds two ticks. 227 * 228 * pps_stbcnt counts the calibration intervals that have been discarded 229 * because the frequency wander exceeds the limit MAXFREQ / 4 (25 us). 230 */ 231 long pps_jitcnt = 0; /* jitter limit exceeded */ 232 long pps_calcnt = 0; /* calibration intervals */ 233 long pps_errcnt = 0; /* calibration errors */ 234 long pps_stbcnt = 0; /* stability limit exceeded */ 235 #endif /* PPS_SYNC */ 236 237 #ifdef EXT_CLOCK 238 /* 239 * External clock definitions 240 * 241 * The following definitions and declarations are used only if an 242 * external clock is configured on the system. 243 */ 244 #define CLOCK_INTERVAL 30 /* CPU clock update interval (s) */ 245 246 /* 247 * The clock_count variable is set to CLOCK_INTERVAL at each PPS 248 * interrupt and decremented once each second. 249 */ 250 int clock_count = 0; /* CPU clock counter */ 251 252 #ifdef HIGHBALL 253 /* 254 * The clock_offset and clock_cpu variables are used by the HIGHBALL 255 * interface. The clock_offset variable defines the offset between 256 * system time and the HIGBALL counters. The clock_cpu variable contains 257 * the offset between the system clock and the HIGHBALL clock for use in 258 * disciplining the kernel time variable. 259 */ 260 extern struct timeval clock_offset; /* Highball clock offset */ 261 long clock_cpu = 0; /* CPU clock adjust */ 262 #endif /* HIGHBALL */ 263 #endif /* EXT_CLOCK */ 264 #endif /* NTP */ 265 266 267 /* 268 * Bump a timeval by a small number of usec's. 269 */ 270 #define BUMPTIME(t, usec) { \ 271 register volatile struct timeval *tp = (t); \ 272 register long us; \ 273 \ 274 tp->tv_usec = us = tp->tv_usec + (usec); \ 275 if (us >= 1000000) { \ 276 tp->tv_usec = us - 1000000; \ 277 tp->tv_sec++; \ 278 } \ 279 } 280 281 int stathz; 282 int schedhz; 283 int profhz; 284 int profprocs; 285 int ticks; 286 static int psdiv, pscnt; /* prof => stat divider */ 287 int psratio; /* ratio: prof / stat */ 288 int tickfix, tickfixinterval; /* used if tick not really integral */ 289 #ifndef NTP 290 static int tickfixcnt; /* accumulated fractional error */ 291 #else 292 int fixtick; /* used by NTP for same */ 293 int shifthz; 294 #endif 295 296 volatile struct timeval time; 297 volatile struct timeval mono_time; 298 299 /* 300 * Initialize clock frequencies and start both clocks running. 301 */ 302 void 303 initclocks() 304 { 305 register int i; 306 307 /* 308 * Set divisors to 1 (normal case) and let the machine-specific 309 * code do its bit. 310 */ 311 psdiv = pscnt = 1; 312 cpu_initclocks(); 313 314 /* 315 * Compute profhz/stathz, and fix profhz if needed. 316 */ 317 i = stathz ? stathz : hz; 318 if (profhz == 0) 319 profhz = i; 320 psratio = profhz / i; 321 322 #ifdef NTP 323 if (time_precision == 0) 324 time_precision = tick; 325 326 switch (hz) { 327 case 60: 328 case 64: 329 shifthz = SHIFT_SCALE - 6; 330 break; 331 case 96: 332 case 100: 333 case 128: 334 shifthz = SHIFT_SCALE - 7; 335 break; 336 case 256: 337 shifthz = SHIFT_SCALE - 8; 338 break; 339 case 1024: 340 shifthz = SHIFT_SCALE - 10; 341 break; 342 default: 343 panic("weird hz"); 344 } 345 #endif 346 } 347 348 /* 349 * The real-time timer, interrupting hz times per second. 350 */ 351 void 352 hardclock(frame) 353 register struct clockframe *frame; 354 { 355 register struct proc *p; 356 register int delta; 357 extern int tickdelta; 358 extern long timedelta; 359 #ifdef NTP 360 register int time_update; 361 struct timeval newtime; 362 register int ltemp; 363 #endif 364 365 p = curproc; 366 if (p) { 367 register struct pstats *pstats; 368 369 /* 370 * Run current process's virtual and profile time, as needed. 371 */ 372 pstats = p->p_stats; 373 if (CLKF_USERMODE(frame) && 374 timerisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) && 375 itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) 376 psignal(p, SIGVTALRM); 377 if (timerisset(&pstats->p_timer[ITIMER_PROF].it_value) && 378 itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) 379 psignal(p, SIGPROF); 380 } 381 382 /* 383 * If no separate statistics clock is available, run it from here. 384 */ 385 if (stathz == 0) 386 statclock(frame); 387 388 /* 389 * Increment the time-of-day. The increment is normally just 390 * ``tick''. If the machine is one which has a clock frequency 391 * such that ``hz'' would not divide the second evenly into 392 * milliseconds, a periodic adjustment must be applied. Finally, 393 * if we are still adjusting the time (see adjtime()), 394 * ``tickdelta'' may also be added in. 395 */ 396 ticks++; 397 delta = tick; 398 399 #ifndef NTP 400 if (tickfix) { 401 tickfixcnt += tickfix; 402 if (tickfixcnt >= tickfixinterval) { 403 delta++; 404 tickfixcnt -= tickfixinterval; 405 } 406 } 407 #else 408 newtime = time; 409 #endif /* !NTP */ 410 /* Imprecise 4bsd adjtime() handling */ 411 if (timedelta != 0) { 412 delta += tickdelta; 413 timedelta -= tickdelta; 414 } 415 416 #ifdef notyet 417 microset(); 418 #endif 419 420 #ifndef NTP 421 BUMPTIME(&time, delta); /* XXX Now done using NTP code below */ 422 #endif 423 BUMPTIME(&mono_time, delta); 424 425 #ifdef NTP 426 time_update = delta; 427 428 /* 429 * Compute the phase adjustment. If the low-order bits 430 * (time_phase) of the update overflow, bump the high-order bits 431 * (time_update). 432 */ 433 time_phase += time_adj; 434 if (time_phase <= -FINEUSEC) { 435 ltemp = -time_phase >> SHIFT_SCALE; 436 time_phase += ltemp << SHIFT_SCALE; 437 time_update -= ltemp; 438 } else if (time_phase >= FINEUSEC) { 439 ltemp = time_phase >> SHIFT_SCALE; 440 time_phase -= ltemp << SHIFT_SCALE; 441 time_update += ltemp; 442 } 443 444 #ifdef HIGHBALL 445 /* 446 * If the HIGHBALL board is installed, we need to adjust the 447 * external clock offset in order to close the hardware feedback 448 * loop. This will adjust the external clock phase and frequency 449 * in small amounts. The additional phase noise and frequency 450 * wander this causes should be minimal. We also need to 451 * discipline the kernel time variable, since the PLL is used to 452 * discipline the external clock. If the Highball board is not 453 * present, we discipline kernel time with the PLL as usual. We 454 * assume that the external clock phase adjustment (time_update) 455 * and kernel phase adjustment (clock_cpu) are less than the 456 * value of tick. 457 */ 458 clock_offset.tv_usec += time_update; 459 if (clock_offset.tv_usec >= 1000000) { 460 clock_offset.tv_sec++; 461 clock_offset.tv_usec -= 1000000; 462 } 463 if (clock_offset.tv_usec < 0) { 464 clock_offset.tv_sec--; 465 clock_offset.tv_usec += 1000000; 466 } 467 newtime.tv_usec += clock_cpu; 468 clock_cpu = 0; 469 #else 470 newtime.tv_usec += time_update; 471 #endif /* HIGHBALL */ 472 473 /* 474 * On rollover of the second the phase adjustment to be used for 475 * the next second is calculated. Also, the maximum error is 476 * increased by the tolerance. If the PPS frequency discipline 477 * code is present, the phase is increased to compensate for the 478 * CPU clock oscillator frequency error. 479 * 480 * On a 32-bit machine and given parameters in the timex.h 481 * header file, the maximum phase adjustment is +-512 ms and 482 * maximum frequency offset is a tad less than) +-512 ppm. On a 483 * 64-bit machine, you shouldn't need to ask. 484 */ 485 if (newtime.tv_usec >= 1000000) { 486 newtime.tv_usec -= 1000000; 487 newtime.tv_sec++; 488 time_maxerror += time_tolerance >> SHIFT_USEC; 489 490 /* 491 * Leap second processing. If in leap-insert state at 492 * the end of the day, the system clock is set back one 493 * second; if in leap-delete state, the system clock is 494 * set ahead one second. The microtime() routine or 495 * external clock driver will insure that reported time 496 * is always monotonic. The ugly divides should be 497 * replaced. 498 */ 499 switch (time_state) { 500 case TIME_OK: 501 if (time_status & STA_INS) 502 time_state = TIME_INS; 503 else if (time_status & STA_DEL) 504 time_state = TIME_DEL; 505 break; 506 507 case TIME_INS: 508 if (newtime.tv_sec % 86400 == 0) { 509 newtime.tv_sec--; 510 time_state = TIME_OOP; 511 } 512 break; 513 514 case TIME_DEL: 515 if ((newtime.tv_sec + 1) % 86400 == 0) { 516 newtime.tv_sec++; 517 time_state = TIME_WAIT; 518 } 519 break; 520 521 case TIME_OOP: 522 time_state = TIME_WAIT; 523 break; 524 525 case TIME_WAIT: 526 if (!(time_status & (STA_INS | STA_DEL))) 527 time_state = TIME_OK; 528 break; 529 } 530 531 /* 532 * Compute the phase adjustment for the next second. In 533 * PLL mode, the offset is reduced by a fixed factor 534 * times the time constant. In FLL mode the offset is 535 * used directly. In either mode, the maximum phase 536 * adjustment for each second is clamped so as to spread 537 * the adjustment over not more than the number of 538 * seconds between updates. 539 */ 540 if (time_offset < 0) { 541 ltemp = -time_offset; 542 if (!(time_status & STA_FLL)) 543 ltemp >>= SHIFT_KG + time_constant; 544 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 545 ltemp = (MAXPHASE / MINSEC) << 546 SHIFT_UPDATE; 547 time_offset += ltemp; 548 time_adj = -ltemp << (shifthz - SHIFT_UPDATE); 549 } else if (time_offset > 0) { 550 ltemp = time_offset; 551 if (!(time_status & STA_FLL)) 552 ltemp >>= SHIFT_KG + time_constant; 553 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 554 ltemp = (MAXPHASE / MINSEC) << 555 SHIFT_UPDATE; 556 time_offset -= ltemp; 557 time_adj = ltemp << (shifthz - SHIFT_UPDATE); 558 } else 559 time_adj = 0; 560 561 /* 562 * Compute the frequency estimate and additional phase 563 * adjustment due to frequency error for the next 564 * second. When the PPS signal is engaged, gnaw on the 565 * watchdog counter and update the frequency computed by 566 * the pll and the PPS signal. 567 */ 568 #ifdef PPS_SYNC 569 pps_valid++; 570 if (pps_valid >= PPS_VALID) { 571 pps_valid = PPS_VALID; /* Avoid possible overflow */ 572 pps_jitter = MAXTIME; 573 pps_stabil = MAXFREQ; 574 time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | 575 STA_PPSWANDER | STA_PPSERROR); 576 } 577 ltemp = time_freq + pps_freq; 578 #else 579 ltemp = time_freq; 580 #endif /* PPS_SYNC */ 581 582 if (ltemp < 0) 583 time_adj -= -ltemp >> (SHIFT_USEC - shifthz); 584 else 585 time_adj += ltemp >> (SHIFT_USEC - shifthz); 586 time_adj += (long)fixtick << shifthz; 587 588 /* 589 * When the CPU clock oscillator frequency is not a 590 * power of 2 in Hz, shifthz is only an approximate 591 * scale factor. 592 */ 593 switch (hz) { 594 case 96: 595 case 100: 596 /* 597 * In the following code the overall gain is increased 598 * by a factor of 1.25, which results in a residual 599 * error less than 3 percent. 600 */ 601 if (time_adj < 0) 602 time_adj -= -time_adj >> 2; 603 else 604 time_adj += time_adj >> 2; 605 break; 606 case 60: 607 /* 608 * 60 Hz m68k and vaxes have a PLL gain factor of of 609 * 60/64 (15/16) of what it should be. In the following code 610 * the overall gain is increased by a factor of 1.0625, 611 * (17/16) which results in a residual error of just less 612 * than 0.4 percent. 613 */ 614 if (time_adj < 0) 615 time_adj -= -time_adj >> 4; 616 else 617 time_adj += time_adj >> 4; 618 break; 619 } 620 621 #ifdef EXT_CLOCK 622 /* 623 * If an external clock is present, it is necessary to 624 * discipline the kernel time variable anyway, since not 625 * all system components use the microtime() interface. 626 * Here, the time offset between the external clock and 627 * kernel time variable is computed every so often. 628 */ 629 clock_count++; 630 if (clock_count > CLOCK_INTERVAL) { 631 clock_count = 0; 632 microtime(&clock_ext); 633 delta.tv_sec = clock_ext.tv_sec - newtime.tv_sec; 634 delta.tv_usec = clock_ext.tv_usec - newtime.tv_usec; 635 if (delta.tv_usec < 0) 636 delta.tv_sec--; 637 if (delta.tv_usec >= 500000) { 638 delta.tv_usec -= 1000000; 639 delta.tv_sec++; 640 } 641 if (delta.tv_usec < -500000) { 642 delta.tv_usec += 1000000; 643 delta.tv_sec--; 644 } 645 if (delta.tv_sec > 0 || (delta.tv_sec == 0 && 646 delta.tv_usec > MAXPHASE) || 647 delta.tv_sec < -1 || (delta.tv_sec == -1 && 648 delta.tv_usec < -MAXPHASE)) { 649 newtime = clock_ext; 650 delta.tv_sec = 0; 651 delta.tv_usec = 0; 652 } 653 #ifdef HIGHBALL 654 clock_cpu = delta.tv_usec; 655 #else /* HIGHBALL */ 656 hardupdate(delta.tv_usec); 657 #endif /* HIGHBALL */ 658 } 659 #endif /* EXT_CLOCK */ 660 } 661 662 #ifdef CPU_CLOCKUPDATE 663 CPU_CLOCKUPDATE(&time, &newtime); 664 #else 665 time = newtime; 666 #endif 667 668 #endif /* NTP */ 669 670 /* 671 * Update real-time timeout queue. 672 * Process callouts at a very low cpu priority, so we don't keep the 673 * relatively high clock interrupt priority any longer than necessary. 674 */ 675 if (timeout_hardclock_update()) { 676 if (CLKF_BASEPRI(frame)) { 677 /* 678 * Save the overhead of a software interrupt; 679 * it will happen as soon as we return, so do it now. 680 */ 681 (void)spllowersoftclock(); 682 softclock(); 683 } else 684 setsoftclock(); 685 } 686 } 687 688 /* 689 * Compute number of hz until specified time. Used to 690 * compute the second argument to timeout_add() from an absolute time. 691 */ 692 int 693 hzto(tv) 694 struct timeval *tv; 695 { 696 unsigned long ticks; 697 long sec, usec; 698 int s; 699 700 /* 701 * If the number of usecs in the whole seconds part of the time 702 * difference fits in a long, then the total number of usecs will 703 * fit in an unsigned long. Compute the total and convert it to 704 * ticks, rounding up and adding 1 to allow for the current tick 705 * to expire. Rounding also depends on unsigned long arithmetic 706 * to avoid overflow. 707 * 708 * Otherwise, if the number of ticks in the whole seconds part of 709 * the time difference fits in a long, then convert the parts to 710 * ticks separately and add, using similar rounding methods and 711 * overflow avoidance. This method would work in the previous 712 * case but it is slightly slower and assumes that hz is integral. 713 * 714 * Otherwise, round the time difference down to the maximum 715 * representable value. 716 * 717 * If ints have 32 bits, then the maximum value for any timeout in 718 * 10ms ticks is 248 days. 719 */ 720 s = splhigh(); 721 sec = tv->tv_sec - time.tv_sec; 722 usec = tv->tv_usec - time.tv_usec; 723 splx(s); 724 if (usec < 0) { 725 sec--; 726 usec += 1000000; 727 } 728 if (sec < 0 || (sec == 0 && usec <= 0)) { 729 ticks = 0; 730 } else if (sec <= LONG_MAX / 1000000) 731 ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1)) 732 / tick + 1; 733 else if (sec <= LONG_MAX / hz) 734 ticks = sec * hz 735 + ((unsigned long)usec + (tick - 1)) / tick + 1; 736 else 737 ticks = LONG_MAX; 738 if (ticks > INT_MAX) 739 ticks = INT_MAX; 740 return ((int)ticks); 741 } 742 743 /* 744 * Start profiling on a process. 745 * 746 * Kernel profiling passes proc0 which never exits and hence 747 * keeps the profile clock running constantly. 748 */ 749 void 750 startprofclock(p) 751 register struct proc *p; 752 { 753 int s; 754 755 if ((p->p_flag & P_PROFIL) == 0) { 756 p->p_flag |= P_PROFIL; 757 if (++profprocs == 1 && stathz != 0) { 758 s = splstatclock(); 759 psdiv = pscnt = psratio; 760 setstatclockrate(profhz); 761 splx(s); 762 } 763 } 764 } 765 766 /* 767 * Stop profiling on a process. 768 */ 769 void 770 stopprofclock(p) 771 register struct proc *p; 772 { 773 int s; 774 775 if (p->p_flag & P_PROFIL) { 776 p->p_flag &= ~P_PROFIL; 777 if (--profprocs == 0 && stathz != 0) { 778 s = splstatclock(); 779 psdiv = pscnt = 1; 780 setstatclockrate(stathz); 781 splx(s); 782 } 783 } 784 } 785 786 /* 787 * Statistics clock. Grab profile sample, and if divider reaches 0, 788 * do process and kernel statistics. 789 */ 790 void 791 statclock(frame) 792 register struct clockframe *frame; 793 { 794 #ifdef GPROF 795 register struct gmonparam *g; 796 register int i; 797 #endif 798 static int schedclk; 799 register struct proc *p; 800 801 if (CLKF_USERMODE(frame)) { 802 p = curproc; 803 if (p->p_flag & P_PROFIL) 804 addupc_intr(p, CLKF_PC(frame), 1); 805 if (--pscnt > 0) 806 return; 807 /* 808 * Came from user mode; CPU was in user state. 809 * If this process is being profiled record the tick. 810 */ 811 p->p_uticks++; 812 if (p->p_nice > NZERO) 813 cp_time[CP_NICE]++; 814 else 815 cp_time[CP_USER]++; 816 } else { 817 #ifdef GPROF 818 /* 819 * Kernel statistics are just like addupc_intr, only easier. 820 */ 821 g = &_gmonparam; 822 if (g->state == GMON_PROF_ON) { 823 i = CLKF_PC(frame) - g->lowpc; 824 if (i < g->textsize) { 825 i /= HISTFRACTION * sizeof(*g->kcount); 826 g->kcount[i]++; 827 } 828 } 829 #endif 830 if (--pscnt > 0) 831 return; 832 /* 833 * Came from kernel mode, so we were: 834 * - handling an interrupt, 835 * - doing syscall or trap work on behalf of the current 836 * user process, or 837 * - spinning in the idle loop. 838 * Whichever it is, charge the time as appropriate. 839 * Note that we charge interrupts to the current process, 840 * regardless of whether they are ``for'' that process, 841 * so that we know how much of its real time was spent 842 * in ``non-process'' (i.e., interrupt) work. 843 */ 844 p = curproc; 845 if (CLKF_INTR(frame)) { 846 if (p != NULL) 847 p->p_iticks++; 848 cp_time[CP_INTR]++; 849 } else if (p != NULL) { 850 p->p_sticks++; 851 cp_time[CP_SYS]++; 852 } else 853 cp_time[CP_IDLE]++; 854 } 855 pscnt = psdiv; 856 857 if (p != NULL) { 858 p->p_cpticks++; 859 /* 860 * If no schedclock is provided, call it here at ~~12-25 Hz; 861 * ~~16 Hz is best 862 */ 863 if (schedhz == 0) 864 if ((++schedclk & 3) == 0) 865 schedclock(p); 866 } 867 } 868 869 870 #ifdef NTP /* NTP phase-locked loop in kernel */ 871 872 /* 873 * hardupdate() - local clock update 874 * 875 * This routine is called by ntp_adjtime() to update the local clock 876 * phase and frequency. The implementation is of an adaptive-parameter, 877 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 878 * time and frequency offset estimates for each call. If the kernel PPS 879 * discipline code is configured (PPS_SYNC), the PPS signal itself 880 * determines the new time offset, instead of the calling argument. 881 * Presumably, calls to ntp_adjtime() occur only when the caller 882 * believes the local clock is valid within some bound (+-128 ms with 883 * NTP). If the caller's time is far different than the PPS time, an 884 * argument will ensue, and it's not clear who will lose. 885 * 886 * For uncompensated quartz crystal oscillatores and nominal update 887 * intervals less than 1024 s, operation should be in phase-lock mode 888 * (STA_FLL = 0), where the loop is disciplined to phase. For update 889 * intervals greater than thiss, operation should be in frequency-lock 890 * mode (STA_FLL = 1), where the loop is disciplined to frequency. 891 * 892 * Note: splclock() is in effect. 893 */ 894 void 895 hardupdate(offset) 896 long offset; 897 { 898 long ltemp, mtemp; 899 900 if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME)) 901 return; 902 ltemp = offset; 903 #ifdef PPS_SYNC 904 if ((time_status & STA_PPSTIME) && (time_status & STA_PPSSIGNAL)) 905 ltemp = pps_offset; 906 #endif /* PPS_SYNC */ 907 908 /* 909 * Scale the phase adjustment and clamp to the operating range. 910 */ 911 if (ltemp > MAXPHASE) 912 time_offset = MAXPHASE << SHIFT_UPDATE; 913 else if (ltemp < -MAXPHASE) 914 time_offset = -(MAXPHASE << SHIFT_UPDATE); 915 else 916 time_offset = ltemp << SHIFT_UPDATE; 917 918 /* 919 * Select whether the frequency is to be controlled and in which 920 * mode (PLL or FLL). Clamp to the operating range. Ugly 921 * multiply/divide should be replaced someday. 922 */ 923 if (time_status & STA_FREQHOLD || time_reftime == 0) 924 time_reftime = time.tv_sec; 925 mtemp = time.tv_sec - time_reftime; 926 time_reftime = time.tv_sec; 927 if (time_status & STA_FLL) { 928 if (mtemp >= MINSEC) { 929 ltemp = ((time_offset / mtemp) << (SHIFT_USEC - 930 SHIFT_UPDATE)); 931 if (ltemp < 0) 932 time_freq -= -ltemp >> SHIFT_KH; 933 else 934 time_freq += ltemp >> SHIFT_KH; 935 } 936 } else { 937 if (mtemp < MAXSEC) { 938 ltemp *= mtemp; 939 if (ltemp < 0) 940 time_freq -= -ltemp >> (time_constant + 941 time_constant + SHIFT_KF - 942 SHIFT_USEC); 943 else 944 time_freq += ltemp >> (time_constant + 945 time_constant + SHIFT_KF - 946 SHIFT_USEC); 947 } 948 } 949 if (time_freq > time_tolerance) 950 time_freq = time_tolerance; 951 else if (time_freq < -time_tolerance) 952 time_freq = -time_tolerance; 953 } 954 955 #ifdef PPS_SYNC 956 /* 957 * hardpps() - discipline CPU clock oscillator to external PPS signal 958 * 959 * This routine is called at each PPS interrupt in order to discipline 960 * the CPU clock oscillator to the PPS signal. It measures the PPS phase 961 * and leaves it in a handy spot for the hardclock() routine. It 962 * integrates successive PPS phase differences and calculates the 963 * frequency offset. This is used in hardclock() to discipline the CPU 964 * clock oscillator so that intrinsic frequency error is cancelled out. 965 * The code requires the caller to capture the time and hardware counter 966 * value at the on-time PPS signal transition. 967 * 968 * Note that, on some Unix systems, this routine runs at an interrupt 969 * priority level higher than the timer interrupt routine hardclock(). 970 * Therefore, the variables used are distinct from the hardclock() 971 * variables, except for certain exceptions: The PPS frequency pps_freq 972 * and phase pps_offset variables are determined by this routine and 973 * updated atomically. The time_tolerance variable can be considered a 974 * constant, since it is infrequently changed, and then only when the 975 * PPS signal is disabled. The watchdog counter pps_valid is updated 976 * once per second by hardclock() and is atomically cleared in this 977 * routine. 978 */ 979 void 980 hardpps(tvp, usec) 981 struct timeval *tvp; /* time at PPS */ 982 long usec; /* hardware counter at PPS */ 983 { 984 long u_usec, v_usec, bigtick; 985 long cal_sec, cal_usec; 986 987 /* 988 * An occasional glitch can be produced when the PPS interrupt 989 * occurs in the hardclock() routine before the time variable is 990 * updated. Here the offset is discarded when the difference 991 * between it and the last one is greater than tick/2, but not 992 * if the interval since the first discard exceeds 30 s. 993 */ 994 time_status |= STA_PPSSIGNAL; 995 time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); 996 pps_valid = 0; 997 u_usec = -tvp->tv_usec; 998 if (u_usec < -500000) 999 u_usec += 1000000; 1000 v_usec = pps_offset - u_usec; 1001 if (v_usec < 0) 1002 v_usec = -v_usec; 1003 if (v_usec > (tick >> 1)) { 1004 if (pps_glitch > MAXGLITCH) { 1005 pps_glitch = 0; 1006 pps_tf[2] = u_usec; 1007 pps_tf[1] = u_usec; 1008 } else { 1009 pps_glitch++; 1010 u_usec = pps_offset; 1011 } 1012 } else 1013 pps_glitch = 0; 1014 1015 /* 1016 * A three-stage median filter is used to help deglitch the pps 1017 * time. The median sample becomes the time offset estimate; the 1018 * difference between the other two samples becomes the time 1019 * dispersion (jitter) estimate. 1020 */ 1021 pps_tf[2] = pps_tf[1]; 1022 pps_tf[1] = pps_tf[0]; 1023 pps_tf[0] = u_usec; 1024 if (pps_tf[0] > pps_tf[1]) { 1025 if (pps_tf[1] > pps_tf[2]) { 1026 pps_offset = pps_tf[1]; /* 0 1 2 */ 1027 v_usec = pps_tf[0] - pps_tf[2]; 1028 } else if (pps_tf[2] > pps_tf[0]) { 1029 pps_offset = pps_tf[0]; /* 2 0 1 */ 1030 v_usec = pps_tf[2] - pps_tf[1]; 1031 } else { 1032 pps_offset = pps_tf[2]; /* 0 2 1 */ 1033 v_usec = pps_tf[0] - pps_tf[1]; 1034 } 1035 } else { 1036 if (pps_tf[1] < pps_tf[2]) { 1037 pps_offset = pps_tf[1]; /* 2 1 0 */ 1038 v_usec = pps_tf[2] - pps_tf[0]; 1039 } else if (pps_tf[2] < pps_tf[0]) { 1040 pps_offset = pps_tf[0]; /* 1 0 2 */ 1041 v_usec = pps_tf[1] - pps_tf[2]; 1042 } else { 1043 pps_offset = pps_tf[2]; /* 1 2 0 */ 1044 v_usec = pps_tf[1] - pps_tf[0]; 1045 } 1046 } 1047 if (v_usec > MAXTIME) 1048 pps_jitcnt++; 1049 v_usec = (v_usec << PPS_AVG) - pps_jitter; 1050 if (v_usec < 0) 1051 pps_jitter -= -v_usec >> PPS_AVG; 1052 else 1053 pps_jitter += v_usec >> PPS_AVG; 1054 if (pps_jitter > (MAXTIME >> 1)) 1055 time_status |= STA_PPSJITTER; 1056 1057 /* 1058 * During the calibration interval adjust the starting time when 1059 * the tick overflows. At the end of the interval compute the 1060 * duration of the interval and the difference of the hardware 1061 * counters at the beginning and end of the interval. This code 1062 * is deliciously complicated by the fact valid differences may 1063 * exceed the value of tick when using long calibration 1064 * intervals and small ticks. Note that the counter can be 1065 * greater than tick if caught at just the wrong instant, but 1066 * the values returned and used here are correct. 1067 */ 1068 bigtick = (long)tick << SHIFT_USEC; 1069 pps_usec -= pps_freq; 1070 if (pps_usec >= bigtick) 1071 pps_usec -= bigtick; 1072 if (pps_usec < 0) 1073 pps_usec += bigtick; 1074 pps_time.tv_sec++; 1075 pps_count++; 1076 if (pps_count < (1 << pps_shift)) 1077 return; 1078 pps_count = 0; 1079 pps_calcnt++; 1080 u_usec = usec << SHIFT_USEC; 1081 v_usec = pps_usec - u_usec; 1082 if (v_usec >= bigtick >> 1) 1083 v_usec -= bigtick; 1084 if (v_usec < -(bigtick >> 1)) 1085 v_usec += bigtick; 1086 if (v_usec < 0) 1087 v_usec = -(-v_usec >> pps_shift); 1088 else 1089 v_usec = v_usec >> pps_shift; 1090 pps_usec = u_usec; 1091 cal_sec = tvp->tv_sec; 1092 cal_usec = tvp->tv_usec; 1093 cal_sec -= pps_time.tv_sec; 1094 cal_usec -= pps_time.tv_usec; 1095 if (cal_usec < 0) { 1096 cal_usec += 1000000; 1097 cal_sec--; 1098 } 1099 pps_time = *tvp; 1100 1101 /* 1102 * Check for lost interrupts, noise, excessive jitter and 1103 * excessive frequency error. The number of timer ticks during 1104 * the interval may vary +-1 tick. Add to this a margin of one 1105 * tick for the PPS signal jitter and maximum frequency 1106 * deviation. If the limits are exceeded, the calibration 1107 * interval is reset to the minimum and we start over. 1108 */ 1109 u_usec = (long)tick << 1; 1110 if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec)) 1111 || (cal_sec == 0 && cal_usec < u_usec)) 1112 || v_usec > time_tolerance || v_usec < -time_tolerance) { 1113 pps_errcnt++; 1114 pps_shift = PPS_SHIFT; 1115 pps_intcnt = 0; 1116 time_status |= STA_PPSERROR; 1117 return; 1118 } 1119 1120 /* 1121 * A three-stage median filter is used to help deglitch the pps 1122 * frequency. The median sample becomes the frequency offset 1123 * estimate; the difference between the other two samples 1124 * becomes the frequency dispersion (stability) estimate. 1125 */ 1126 pps_ff[2] = pps_ff[1]; 1127 pps_ff[1] = pps_ff[0]; 1128 pps_ff[0] = v_usec; 1129 if (pps_ff[0] > pps_ff[1]) { 1130 if (pps_ff[1] > pps_ff[2]) { 1131 u_usec = pps_ff[1]; /* 0 1 2 */ 1132 v_usec = pps_ff[0] - pps_ff[2]; 1133 } else if (pps_ff[2] > pps_ff[0]) { 1134 u_usec = pps_ff[0]; /* 2 0 1 */ 1135 v_usec = pps_ff[2] - pps_ff[1]; 1136 } else { 1137 u_usec = pps_ff[2]; /* 0 2 1 */ 1138 v_usec = pps_ff[0] - pps_ff[1]; 1139 } 1140 } else { 1141 if (pps_ff[1] < pps_ff[2]) { 1142 u_usec = pps_ff[1]; /* 2 1 0 */ 1143 v_usec = pps_ff[2] - pps_ff[0]; 1144 } else if (pps_ff[2] < pps_ff[0]) { 1145 u_usec = pps_ff[0]; /* 1 0 2 */ 1146 v_usec = pps_ff[1] - pps_ff[2]; 1147 } else { 1148 u_usec = pps_ff[2]; /* 1 2 0 */ 1149 v_usec = pps_ff[1] - pps_ff[0]; 1150 } 1151 } 1152 1153 /* 1154 * Here the frequency dispersion (stability) is updated. If it 1155 * is less than one-fourth the maximum (MAXFREQ), the frequency 1156 * offset is updated as well, but clamped to the tolerance. It 1157 * will be processed later by the hardclock() routine. 1158 */ 1159 v_usec = (v_usec >> 1) - pps_stabil; 1160 if (v_usec < 0) 1161 pps_stabil -= -v_usec >> PPS_AVG; 1162 else 1163 pps_stabil += v_usec >> PPS_AVG; 1164 if (pps_stabil > MAXFREQ >> 2) { 1165 pps_stbcnt++; 1166 time_status |= STA_PPSWANDER; 1167 return; 1168 } 1169 if (time_status & STA_PPSFREQ) { 1170 if (u_usec < 0) { 1171 pps_freq -= -u_usec >> PPS_AVG; 1172 if (pps_freq < -time_tolerance) 1173 pps_freq = -time_tolerance; 1174 u_usec = -u_usec; 1175 } else { 1176 pps_freq += u_usec >> PPS_AVG; 1177 if (pps_freq > time_tolerance) 1178 pps_freq = time_tolerance; 1179 } 1180 } 1181 1182 /* 1183 * Here the calibration interval is adjusted. If the maximum 1184 * time difference is greater than tick / 4, reduce the interval 1185 * by half. If this is not the case for four consecutive 1186 * intervals, double the interval. 1187 */ 1188 if (u_usec << pps_shift > bigtick >> 2) { 1189 pps_intcnt = 0; 1190 if (pps_shift > PPS_SHIFT) 1191 pps_shift--; 1192 } else if (pps_intcnt >= 4) { 1193 pps_intcnt = 0; 1194 if (pps_shift < PPS_SHIFTMAX) 1195 pps_shift++; 1196 } else 1197 pps_intcnt++; 1198 } 1199 #endif /* PPS_SYNC */ 1200 #endif /* NTP */ 1201 1202 1203 /* 1204 * Return information about system clocks. 1205 */ 1206 int 1207 sysctl_clockrate(where, sizep) 1208 register char *where; 1209 size_t *sizep; 1210 { 1211 struct clockinfo clkinfo; 1212 1213 /* 1214 * Construct clockinfo structure. 1215 */ 1216 clkinfo.tick = tick; 1217 clkinfo.tickadj = tickadj; 1218 clkinfo.hz = hz; 1219 clkinfo.profhz = profhz; 1220 clkinfo.stathz = stathz ? stathz : hz; 1221 return (sysctl_rdstruct(where, sizep, NULL, &clkinfo, sizeof(clkinfo))); 1222 } 1223