1 /* $OpenBSD: kern_clock.c,v 1.25 2000/07/06 15:33:31 ho 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, needsoft; 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 /* 366 * Update real-time timeout queue. 367 */ 368 needsoft = timeout_hardclock_update(); 369 370 p = curproc; 371 if (p) { 372 register struct pstats *pstats; 373 374 /* 375 * Run current process's virtual and profile time, as needed. 376 */ 377 pstats = p->p_stats; 378 if (CLKF_USERMODE(frame) && 379 timerisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) && 380 itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) 381 psignal(p, SIGVTALRM); 382 if (timerisset(&pstats->p_timer[ITIMER_PROF].it_value) && 383 itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) 384 psignal(p, SIGPROF); 385 } 386 387 /* 388 * If no separate statistics clock is available, run it from here. 389 */ 390 if (stathz == 0) 391 statclock(frame); 392 393 /* 394 * Increment the time-of-day. The increment is normally just 395 * ``tick''. If the machine is one which has a clock frequency 396 * such that ``hz'' would not divide the second evenly into 397 * milliseconds, a periodic adjustment must be applied. Finally, 398 * if we are still adjusting the time (see adjtime()), 399 * ``tickdelta'' may also be added in. 400 */ 401 ticks++; 402 delta = tick; 403 404 #ifndef NTP 405 if (tickfix) { 406 tickfixcnt += tickfix; 407 if (tickfixcnt >= tickfixinterval) { 408 delta++; 409 tickfixcnt -= tickfixinterval; 410 } 411 } 412 #else 413 newtime = time; 414 #endif /* !NTP */ 415 /* Imprecise 4bsd adjtime() handling */ 416 if (timedelta != 0) { 417 delta += tickdelta; 418 timedelta -= tickdelta; 419 } 420 421 #ifdef notyet 422 microset(); 423 #endif 424 425 #ifndef NTP 426 BUMPTIME(&time, delta); /* XXX Now done using NTP code below */ 427 #endif 428 BUMPTIME(&mono_time, delta); 429 430 #ifdef NTP 431 time_update = delta; 432 433 /* 434 * Compute the phase adjustment. If the low-order bits 435 * (time_phase) of the update overflow, bump the high-order bits 436 * (time_update). 437 */ 438 time_phase += time_adj; 439 if (time_phase <= -FINEUSEC) { 440 ltemp = -time_phase >> SHIFT_SCALE; 441 time_phase += ltemp << SHIFT_SCALE; 442 time_update -= ltemp; 443 } else if (time_phase >= FINEUSEC) { 444 ltemp = time_phase >> SHIFT_SCALE; 445 time_phase -= ltemp << SHIFT_SCALE; 446 time_update += ltemp; 447 } 448 449 #ifdef HIGHBALL 450 /* 451 * If the HIGHBALL board is installed, we need to adjust the 452 * external clock offset in order to close the hardware feedback 453 * loop. This will adjust the external clock phase and frequency 454 * in small amounts. The additional phase noise and frequency 455 * wander this causes should be minimal. We also need to 456 * discipline the kernel time variable, since the PLL is used to 457 * discipline the external clock. If the Highball board is not 458 * present, we discipline kernel time with the PLL as usual. We 459 * assume that the external clock phase adjustment (time_update) 460 * and kernel phase adjustment (clock_cpu) are less than the 461 * value of tick. 462 */ 463 clock_offset.tv_usec += time_update; 464 if (clock_offset.tv_usec >= 1000000) { 465 clock_offset.tv_sec++; 466 clock_offset.tv_usec -= 1000000; 467 } 468 if (clock_offset.tv_usec < 0) { 469 clock_offset.tv_sec--; 470 clock_offset.tv_usec += 1000000; 471 } 472 newtime.tv_usec += clock_cpu; 473 clock_cpu = 0; 474 #else 475 newtime.tv_usec += time_update; 476 #endif /* HIGHBALL */ 477 478 /* 479 * On rollover of the second the phase adjustment to be used for 480 * the next second is calculated. Also, the maximum error is 481 * increased by the tolerance. If the PPS frequency discipline 482 * code is present, the phase is increased to compensate for the 483 * CPU clock oscillator frequency error. 484 * 485 * On a 32-bit machine and given parameters in the timex.h 486 * header file, the maximum phase adjustment is +-512 ms and 487 * maximum frequency offset is a tad less than) +-512 ppm. On a 488 * 64-bit machine, you shouldn't need to ask. 489 */ 490 if (newtime.tv_usec >= 1000000) { 491 newtime.tv_usec -= 1000000; 492 newtime.tv_sec++; 493 time_maxerror += time_tolerance >> SHIFT_USEC; 494 495 /* 496 * Leap second processing. If in leap-insert state at 497 * the end of the day, the system clock is set back one 498 * second; if in leap-delete state, the system clock is 499 * set ahead one second. The microtime() routine or 500 * external clock driver will insure that reported time 501 * is always monotonic. The ugly divides should be 502 * replaced. 503 */ 504 switch (time_state) { 505 case TIME_OK: 506 if (time_status & STA_INS) 507 time_state = TIME_INS; 508 else if (time_status & STA_DEL) 509 time_state = TIME_DEL; 510 break; 511 512 case TIME_INS: 513 if (newtime.tv_sec % 86400 == 0) { 514 newtime.tv_sec--; 515 time_state = TIME_OOP; 516 } 517 break; 518 519 case TIME_DEL: 520 if ((newtime.tv_sec + 1) % 86400 == 0) { 521 newtime.tv_sec++; 522 time_state = TIME_WAIT; 523 } 524 break; 525 526 case TIME_OOP: 527 time_state = TIME_WAIT; 528 break; 529 530 case TIME_WAIT: 531 if (!(time_status & (STA_INS | STA_DEL))) 532 time_state = TIME_OK; 533 break; 534 } 535 536 /* 537 * Compute the phase adjustment for the next second. In 538 * PLL mode, the offset is reduced by a fixed factor 539 * times the time constant. In FLL mode the offset is 540 * used directly. In either mode, the maximum phase 541 * adjustment for each second is clamped so as to spread 542 * the adjustment over not more than the number of 543 * seconds between updates. 544 */ 545 if (time_offset < 0) { 546 ltemp = -time_offset; 547 if (!(time_status & STA_FLL)) 548 ltemp >>= SHIFT_KG + time_constant; 549 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 550 ltemp = (MAXPHASE / MINSEC) << 551 SHIFT_UPDATE; 552 time_offset += ltemp; 553 time_adj = -ltemp << (shifthz - SHIFT_UPDATE); 554 } else if (time_offset > 0) { 555 ltemp = time_offset; 556 if (!(time_status & STA_FLL)) 557 ltemp >>= SHIFT_KG + time_constant; 558 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 559 ltemp = (MAXPHASE / MINSEC) << 560 SHIFT_UPDATE; 561 time_offset -= ltemp; 562 time_adj = ltemp << (shifthz - SHIFT_UPDATE); 563 } else 564 time_adj = 0; 565 566 /* 567 * Compute the frequency estimate and additional phase 568 * adjustment due to frequency error for the next 569 * second. When the PPS signal is engaged, gnaw on the 570 * watchdog counter and update the frequency computed by 571 * the pll and the PPS signal. 572 */ 573 #ifdef PPS_SYNC 574 pps_valid++; 575 if (pps_valid >= PPS_VALID) { 576 pps_valid = PPS_VALID; /* Avoid possible overflow */ 577 pps_jitter = MAXTIME; 578 pps_stabil = MAXFREQ; 579 time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | 580 STA_PPSWANDER | STA_PPSERROR); 581 } 582 ltemp = time_freq + pps_freq; 583 #else 584 ltemp = time_freq; 585 #endif /* PPS_SYNC */ 586 587 if (ltemp < 0) 588 time_adj -= -ltemp >> (SHIFT_USEC - shifthz); 589 else 590 time_adj += ltemp >> (SHIFT_USEC - shifthz); 591 time_adj += (long)fixtick << shifthz; 592 593 /* 594 * When the CPU clock oscillator frequency is not a 595 * power of 2 in Hz, shifthz is only an approximate 596 * scale factor. 597 */ 598 switch (hz) { 599 case 96: 600 case 100: 601 /* 602 * In the following code the overall gain is increased 603 * by a factor of 1.25, which results in a residual 604 * error less than 3 percent. 605 */ 606 if (time_adj < 0) 607 time_adj -= -time_adj >> 2; 608 else 609 time_adj += time_adj >> 2; 610 break; 611 case 60: 612 /* 613 * 60 Hz m68k and vaxes have a PLL gain factor of of 614 * 60/64 (15/16) of what it should be. In the following code 615 * the overall gain is increased by a factor of 1.0625, 616 * (17/16) which results in a residual error of just less 617 * than 0.4 percent. 618 */ 619 if (time_adj < 0) 620 time_adj -= -time_adj >> 4; 621 else 622 time_adj += time_adj >> 4; 623 break; 624 } 625 626 #ifdef EXT_CLOCK 627 /* 628 * If an external clock is present, it is necessary to 629 * discipline the kernel time variable anyway, since not 630 * all system components use the microtime() interface. 631 * Here, the time offset between the external clock and 632 * kernel time variable is computed every so often. 633 */ 634 clock_count++; 635 if (clock_count > CLOCK_INTERVAL) { 636 clock_count = 0; 637 microtime(&clock_ext); 638 delta.tv_sec = clock_ext.tv_sec - newtime.tv_sec; 639 delta.tv_usec = clock_ext.tv_usec - newtime.tv_usec; 640 if (delta.tv_usec < 0) 641 delta.tv_sec--; 642 if (delta.tv_usec >= 500000) { 643 delta.tv_usec -= 1000000; 644 delta.tv_sec++; 645 } 646 if (delta.tv_usec < -500000) { 647 delta.tv_usec += 1000000; 648 delta.tv_sec--; 649 } 650 if (delta.tv_sec > 0 || (delta.tv_sec == 0 && 651 delta.tv_usec > MAXPHASE) || 652 delta.tv_sec < -1 || (delta.tv_sec == -1 && 653 delta.tv_usec < -MAXPHASE)) { 654 newtime = clock_ext; 655 delta.tv_sec = 0; 656 delta.tv_usec = 0; 657 } 658 #ifdef HIGHBALL 659 clock_cpu = delta.tv_usec; 660 #else /* HIGHBALL */ 661 hardupdate(delta.tv_usec); 662 #endif /* HIGHBALL */ 663 } 664 #endif /* EXT_CLOCK */ 665 } 666 667 #ifdef CPU_CLOCKUPDATE 668 CPU_CLOCKUPDATE(&time, &newtime); 669 #else 670 time = newtime; 671 #endif 672 673 #endif /* NTP */ 674 675 /* 676 * Process callouts at a very low cpu priority, so we don't keep the 677 * relatively high clock interrupt priority any longer than necessary. 678 */ 679 if (needsoft) { 680 if (CLKF_BASEPRI(frame)) { 681 /* 682 * Save the overhead of a software interrupt; 683 * it will happen as soon as we return, so do it now. 684 */ 685 (void)spllowersoftclock(); 686 softclock(); 687 } else 688 setsoftclock(); 689 } 690 } 691 692 /* 693 * Compute number of hz until specified time. Used to 694 * compute the second argument to timeout_add() from an absolute time. 695 */ 696 int 697 hzto(tv) 698 struct timeval *tv; 699 { 700 register unsigned long ticks; 701 register long sec, usec; 702 int s; 703 704 /* 705 * If the number of usecs in the whole seconds part of the time 706 * difference fits in a long, then the total number of usecs will 707 * fit in an unsigned long. Compute the total and convert it to 708 * ticks, rounding up and adding 1 to allow for the current tick 709 * to expire. Rounding also depends on unsigned long arithmetic 710 * to avoid overflow. 711 * 712 * Otherwise, if the number of ticks in the whole seconds part of 713 * the time difference fits in a long, then convert the parts to 714 * ticks separately and add, using similar rounding methods and 715 * overflow avoidance. This method would work in the previous 716 * case but it is slightly slower and assumes that hz is integral. 717 * 718 * Otherwise, round the time difference down to the maximum 719 * representable value. 720 * 721 * If ints have 32 bits, then the maximum value for any timeout in 722 * 10ms ticks is 248 days. 723 */ 724 s = splhigh(); 725 sec = tv->tv_sec - time.tv_sec; 726 usec = tv->tv_usec - time.tv_usec; 727 splx(s); 728 if (usec < 0) { 729 sec--; 730 usec += 1000000; 731 } 732 if (sec < 0) { 733 ticks = 1; 734 } else if (sec <= LONG_MAX / 1000000) 735 ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1)) 736 / tick + 1; 737 else if (sec <= LONG_MAX / hz) 738 ticks = sec * hz 739 + ((unsigned long)usec + (tick - 1)) / tick + 1; 740 else 741 ticks = LONG_MAX; 742 if (ticks > INT_MAX) 743 ticks = INT_MAX; 744 return ((int)ticks); 745 } 746 747 /* 748 * Start profiling on a process. 749 * 750 * Kernel profiling passes proc0 which never exits and hence 751 * keeps the profile clock running constantly. 752 */ 753 void 754 startprofclock(p) 755 register struct proc *p; 756 { 757 int s; 758 759 if ((p->p_flag & P_PROFIL) == 0) { 760 p->p_flag |= P_PROFIL; 761 if (++profprocs == 1 && stathz != 0) { 762 s = splstatclock(); 763 psdiv = pscnt = psratio; 764 setstatclockrate(profhz); 765 splx(s); 766 } 767 } 768 } 769 770 /* 771 * Stop profiling on a process. 772 */ 773 void 774 stopprofclock(p) 775 register struct proc *p; 776 { 777 int s; 778 779 if (p->p_flag & P_PROFIL) { 780 p->p_flag &= ~P_PROFIL; 781 if (--profprocs == 0 && stathz != 0) { 782 s = splstatclock(); 783 psdiv = pscnt = 1; 784 setstatclockrate(stathz); 785 splx(s); 786 } 787 } 788 } 789 790 /* 791 * Statistics clock. Grab profile sample, and if divider reaches 0, 792 * do process and kernel statistics. 793 */ 794 void 795 statclock(frame) 796 register struct clockframe *frame; 797 { 798 #ifdef GPROF 799 register struct gmonparam *g; 800 register int i; 801 #endif 802 static int schedclk; 803 register struct proc *p; 804 805 if (CLKF_USERMODE(frame)) { 806 p = curproc; 807 if (p->p_flag & P_PROFIL) 808 addupc_intr(p, CLKF_PC(frame), 1); 809 if (--pscnt > 0) 810 return; 811 /* 812 * Came from user mode; CPU was in user state. 813 * If this process is being profiled record the tick. 814 */ 815 p->p_uticks++; 816 if (p->p_nice > NZERO) 817 cp_time[CP_NICE]++; 818 else 819 cp_time[CP_USER]++; 820 } else { 821 #ifdef GPROF 822 /* 823 * Kernel statistics are just like addupc_intr, only easier. 824 */ 825 g = &_gmonparam; 826 if (g->state == GMON_PROF_ON) { 827 i = CLKF_PC(frame) - g->lowpc; 828 if (i < g->textsize) { 829 i /= HISTFRACTION * sizeof(*g->kcount); 830 g->kcount[i]++; 831 } 832 } 833 #endif 834 if (--pscnt > 0) 835 return; 836 /* 837 * Came from kernel mode, so we were: 838 * - handling an interrupt, 839 * - doing syscall or trap work on behalf of the current 840 * user process, or 841 * - spinning in the idle loop. 842 * Whichever it is, charge the time as appropriate. 843 * Note that we charge interrupts to the current process, 844 * regardless of whether they are ``for'' that process, 845 * so that we know how much of its real time was spent 846 * in ``non-process'' (i.e., interrupt) work. 847 */ 848 p = curproc; 849 if (CLKF_INTR(frame)) { 850 if (p != NULL) 851 p->p_iticks++; 852 cp_time[CP_INTR]++; 853 } else if (p != NULL) { 854 p->p_sticks++; 855 cp_time[CP_SYS]++; 856 } else 857 cp_time[CP_IDLE]++; 858 } 859 pscnt = psdiv; 860 861 if (p != NULL) { 862 p->p_cpticks++; 863 /* 864 * If no schedclock is provided, call it here at ~~12-25 Hz; 865 * ~~16 Hz is best 866 */ 867 if (schedhz == 0) 868 if ((++schedclk & 3) == 0) 869 schedclock(p); 870 } 871 } 872 873 874 #ifdef NTP /* NTP phase-locked loop in kernel */ 875 876 /* 877 * hardupdate() - local clock update 878 * 879 * This routine is called by ntp_adjtime() to update the local clock 880 * phase and frequency. The implementation is of an adaptive-parameter, 881 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 882 * time and frequency offset estimates for each call. If the kernel PPS 883 * discipline code is configured (PPS_SYNC), the PPS signal itself 884 * determines the new time offset, instead of the calling argument. 885 * Presumably, calls to ntp_adjtime() occur only when the caller 886 * believes the local clock is valid within some bound (+-128 ms with 887 * NTP). If the caller's time is far different than the PPS time, an 888 * argument will ensue, and it's not clear who will lose. 889 * 890 * For uncompensated quartz crystal oscillatores and nominal update 891 * intervals less than 1024 s, operation should be in phase-lock mode 892 * (STA_FLL = 0), where the loop is disciplined to phase. For update 893 * intervals greater than thiss, operation should be in frequency-lock 894 * mode (STA_FLL = 1), where the loop is disciplined to frequency. 895 * 896 * Note: splclock() is in effect. 897 */ 898 void 899 hardupdate(offset) 900 long offset; 901 { 902 long ltemp, mtemp; 903 904 if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME)) 905 return; 906 ltemp = offset; 907 #ifdef PPS_SYNC 908 if ((time_status & STA_PPSTIME) && (time_status & STA_PPSSIGNAL)) 909 ltemp = pps_offset; 910 #endif /* PPS_SYNC */ 911 912 /* 913 * Scale the phase adjustment and clamp to the operating range. 914 */ 915 if (ltemp > MAXPHASE) 916 time_offset = MAXPHASE << SHIFT_UPDATE; 917 else if (ltemp < -MAXPHASE) 918 time_offset = -(MAXPHASE << SHIFT_UPDATE); 919 else 920 time_offset = ltemp << SHIFT_UPDATE; 921 922 /* 923 * Select whether the frequency is to be controlled and in which 924 * mode (PLL or FLL). Clamp to the operating range. Ugly 925 * multiply/divide should be replaced someday. 926 */ 927 if (time_status & STA_FREQHOLD || time_reftime == 0) 928 time_reftime = time.tv_sec; 929 mtemp = time.tv_sec - time_reftime; 930 time_reftime = time.tv_sec; 931 if (time_status & STA_FLL) { 932 if (mtemp >= MINSEC) { 933 ltemp = ((time_offset / mtemp) << (SHIFT_USEC - 934 SHIFT_UPDATE)); 935 if (ltemp < 0) 936 time_freq -= -ltemp >> SHIFT_KH; 937 else 938 time_freq += ltemp >> SHIFT_KH; 939 } 940 } else { 941 if (mtemp < MAXSEC) { 942 ltemp *= mtemp; 943 if (ltemp < 0) 944 time_freq -= -ltemp >> (time_constant + 945 time_constant + SHIFT_KF - 946 SHIFT_USEC); 947 else 948 time_freq += ltemp >> (time_constant + 949 time_constant + SHIFT_KF - 950 SHIFT_USEC); 951 } 952 } 953 if (time_freq > time_tolerance) 954 time_freq = time_tolerance; 955 else if (time_freq < -time_tolerance) 956 time_freq = -time_tolerance; 957 } 958 959 #ifdef PPS_SYNC 960 /* 961 * hardpps() - discipline CPU clock oscillator to external PPS signal 962 * 963 * This routine is called at each PPS interrupt in order to discipline 964 * the CPU clock oscillator to the PPS signal. It measures the PPS phase 965 * and leaves it in a handy spot for the hardclock() routine. It 966 * integrates successive PPS phase differences and calculates the 967 * frequency offset. This is used in hardclock() to discipline the CPU 968 * clock oscillator so that intrinsic frequency error is cancelled out. 969 * The code requires the caller to capture the time and hardware counter 970 * value at the on-time PPS signal transition. 971 * 972 * Note that, on some Unix systems, this routine runs at an interrupt 973 * priority level higher than the timer interrupt routine hardclock(). 974 * Therefore, the variables used are distinct from the hardclock() 975 * variables, except for certain exceptions: The PPS frequency pps_freq 976 * and phase pps_offset variables are determined by this routine and 977 * updated atomically. The time_tolerance variable can be considered a 978 * constant, since it is infrequently changed, and then only when the 979 * PPS signal is disabled. The watchdog counter pps_valid is updated 980 * once per second by hardclock() and is atomically cleared in this 981 * routine. 982 */ 983 void 984 hardpps(tvp, usec) 985 struct timeval *tvp; /* time at PPS */ 986 long usec; /* hardware counter at PPS */ 987 { 988 long u_usec, v_usec, bigtick; 989 long cal_sec, cal_usec; 990 991 /* 992 * An occasional glitch can be produced when the PPS interrupt 993 * occurs in the hardclock() routine before the time variable is 994 * updated. Here the offset is discarded when the difference 995 * between it and the last one is greater than tick/2, but not 996 * if the interval since the first discard exceeds 30 s. 997 */ 998 time_status |= STA_PPSSIGNAL; 999 time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); 1000 pps_valid = 0; 1001 u_usec = -tvp->tv_usec; 1002 if (u_usec < -500000) 1003 u_usec += 1000000; 1004 v_usec = pps_offset - u_usec; 1005 if (v_usec < 0) 1006 v_usec = -v_usec; 1007 if (v_usec > (tick >> 1)) { 1008 if (pps_glitch > MAXGLITCH) { 1009 pps_glitch = 0; 1010 pps_tf[2] = u_usec; 1011 pps_tf[1] = u_usec; 1012 } else { 1013 pps_glitch++; 1014 u_usec = pps_offset; 1015 } 1016 } else 1017 pps_glitch = 0; 1018 1019 /* 1020 * A three-stage median filter is used to help deglitch the pps 1021 * time. The median sample becomes the time offset estimate; the 1022 * difference between the other two samples becomes the time 1023 * dispersion (jitter) estimate. 1024 */ 1025 pps_tf[2] = pps_tf[1]; 1026 pps_tf[1] = pps_tf[0]; 1027 pps_tf[0] = u_usec; 1028 if (pps_tf[0] > pps_tf[1]) { 1029 if (pps_tf[1] > pps_tf[2]) { 1030 pps_offset = pps_tf[1]; /* 0 1 2 */ 1031 v_usec = pps_tf[0] - pps_tf[2]; 1032 } else if (pps_tf[2] > pps_tf[0]) { 1033 pps_offset = pps_tf[0]; /* 2 0 1 */ 1034 v_usec = pps_tf[2] - pps_tf[1]; 1035 } else { 1036 pps_offset = pps_tf[2]; /* 0 2 1 */ 1037 v_usec = pps_tf[0] - pps_tf[1]; 1038 } 1039 } else { 1040 if (pps_tf[1] < pps_tf[2]) { 1041 pps_offset = pps_tf[1]; /* 2 1 0 */ 1042 v_usec = pps_tf[2] - pps_tf[0]; 1043 } else if (pps_tf[2] < pps_tf[0]) { 1044 pps_offset = pps_tf[0]; /* 1 0 2 */ 1045 v_usec = pps_tf[1] - pps_tf[2]; 1046 } else { 1047 pps_offset = pps_tf[2]; /* 1 2 0 */ 1048 v_usec = pps_tf[1] - pps_tf[0]; 1049 } 1050 } 1051 if (v_usec > MAXTIME) 1052 pps_jitcnt++; 1053 v_usec = (v_usec << PPS_AVG) - pps_jitter; 1054 if (v_usec < 0) 1055 pps_jitter -= -v_usec >> PPS_AVG; 1056 else 1057 pps_jitter += v_usec >> PPS_AVG; 1058 if (pps_jitter > (MAXTIME >> 1)) 1059 time_status |= STA_PPSJITTER; 1060 1061 /* 1062 * During the calibration interval adjust the starting time when 1063 * the tick overflows. At the end of the interval compute the 1064 * duration of the interval and the difference of the hardware 1065 * counters at the beginning and end of the interval. This code 1066 * is deliciously complicated by the fact valid differences may 1067 * exceed the value of tick when using long calibration 1068 * intervals and small ticks. Note that the counter can be 1069 * greater than tick if caught at just the wrong instant, but 1070 * the values returned and used here are correct. 1071 */ 1072 bigtick = (long)tick << SHIFT_USEC; 1073 pps_usec -= pps_freq; 1074 if (pps_usec >= bigtick) 1075 pps_usec -= bigtick; 1076 if (pps_usec < 0) 1077 pps_usec += bigtick; 1078 pps_time.tv_sec++; 1079 pps_count++; 1080 if (pps_count < (1 << pps_shift)) 1081 return; 1082 pps_count = 0; 1083 pps_calcnt++; 1084 u_usec = usec << SHIFT_USEC; 1085 v_usec = pps_usec - u_usec; 1086 if (v_usec >= bigtick >> 1) 1087 v_usec -= bigtick; 1088 if (v_usec < -(bigtick >> 1)) 1089 v_usec += bigtick; 1090 if (v_usec < 0) 1091 v_usec = -(-v_usec >> pps_shift); 1092 else 1093 v_usec = v_usec >> pps_shift; 1094 pps_usec = u_usec; 1095 cal_sec = tvp->tv_sec; 1096 cal_usec = tvp->tv_usec; 1097 cal_sec -= pps_time.tv_sec; 1098 cal_usec -= pps_time.tv_usec; 1099 if (cal_usec < 0) { 1100 cal_usec += 1000000; 1101 cal_sec--; 1102 } 1103 pps_time = *tvp; 1104 1105 /* 1106 * Check for lost interrupts, noise, excessive jitter and 1107 * excessive frequency error. The number of timer ticks during 1108 * the interval may vary +-1 tick. Add to this a margin of one 1109 * tick for the PPS signal jitter and maximum frequency 1110 * deviation. If the limits are exceeded, the calibration 1111 * interval is reset to the minimum and we start over. 1112 */ 1113 u_usec = (long)tick << 1; 1114 if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec)) 1115 || (cal_sec == 0 && cal_usec < u_usec)) 1116 || v_usec > time_tolerance || v_usec < -time_tolerance) { 1117 pps_errcnt++; 1118 pps_shift = PPS_SHIFT; 1119 pps_intcnt = 0; 1120 time_status |= STA_PPSERROR; 1121 return; 1122 } 1123 1124 /* 1125 * A three-stage median filter is used to help deglitch the pps 1126 * frequency. The median sample becomes the frequency offset 1127 * estimate; the difference between the other two samples 1128 * becomes the frequency dispersion (stability) estimate. 1129 */ 1130 pps_ff[2] = pps_ff[1]; 1131 pps_ff[1] = pps_ff[0]; 1132 pps_ff[0] = v_usec; 1133 if (pps_ff[0] > pps_ff[1]) { 1134 if (pps_ff[1] > pps_ff[2]) { 1135 u_usec = pps_ff[1]; /* 0 1 2 */ 1136 v_usec = pps_ff[0] - pps_ff[2]; 1137 } else if (pps_ff[2] > pps_ff[0]) { 1138 u_usec = pps_ff[0]; /* 2 0 1 */ 1139 v_usec = pps_ff[2] - pps_ff[1]; 1140 } else { 1141 u_usec = pps_ff[2]; /* 0 2 1 */ 1142 v_usec = pps_ff[0] - pps_ff[1]; 1143 } 1144 } else { 1145 if (pps_ff[1] < pps_ff[2]) { 1146 u_usec = pps_ff[1]; /* 2 1 0 */ 1147 v_usec = pps_ff[2] - pps_ff[0]; 1148 } else if (pps_ff[2] < pps_ff[0]) { 1149 u_usec = pps_ff[0]; /* 1 0 2 */ 1150 v_usec = pps_ff[1] - pps_ff[2]; 1151 } else { 1152 u_usec = pps_ff[2]; /* 1 2 0 */ 1153 v_usec = pps_ff[1] - pps_ff[0]; 1154 } 1155 } 1156 1157 /* 1158 * Here the frequency dispersion (stability) is updated. If it 1159 * is less than one-fourth the maximum (MAXFREQ), the frequency 1160 * offset is updated as well, but clamped to the tolerance. It 1161 * will be processed later by the hardclock() routine. 1162 */ 1163 v_usec = (v_usec >> 1) - pps_stabil; 1164 if (v_usec < 0) 1165 pps_stabil -= -v_usec >> PPS_AVG; 1166 else 1167 pps_stabil += v_usec >> PPS_AVG; 1168 if (pps_stabil > MAXFREQ >> 2) { 1169 pps_stbcnt++; 1170 time_status |= STA_PPSWANDER; 1171 return; 1172 } 1173 if (time_status & STA_PPSFREQ) { 1174 if (u_usec < 0) { 1175 pps_freq -= -u_usec >> PPS_AVG; 1176 if (pps_freq < -time_tolerance) 1177 pps_freq = -time_tolerance; 1178 u_usec = -u_usec; 1179 } else { 1180 pps_freq += u_usec >> PPS_AVG; 1181 if (pps_freq > time_tolerance) 1182 pps_freq = time_tolerance; 1183 } 1184 } 1185 1186 /* 1187 * Here the calibration interval is adjusted. If the maximum 1188 * time difference is greater than tick / 4, reduce the interval 1189 * by half. If this is not the case for four consecutive 1190 * intervals, double the interval. 1191 */ 1192 if (u_usec << pps_shift > bigtick >> 2) { 1193 pps_intcnt = 0; 1194 if (pps_shift > PPS_SHIFT) 1195 pps_shift--; 1196 } else if (pps_intcnt >= 4) { 1197 pps_intcnt = 0; 1198 if (pps_shift < PPS_SHIFTMAX) 1199 pps_shift++; 1200 } else 1201 pps_intcnt++; 1202 } 1203 #endif /* PPS_SYNC */ 1204 #endif /* NTP */ 1205 1206 1207 /* 1208 * Return information about system clocks. 1209 */ 1210 int 1211 sysctl_clockrate(where, sizep) 1212 register char *where; 1213 size_t *sizep; 1214 { 1215 struct clockinfo clkinfo; 1216 1217 /* 1218 * Construct clockinfo structure. 1219 */ 1220 clkinfo.tick = tick; 1221 clkinfo.tickadj = tickadj; 1222 clkinfo.hz = hz; 1223 clkinfo.profhz = profhz; 1224 clkinfo.stathz = stathz ? stathz : hz; 1225 return (sysctl_rdstruct(where, sizep, NULL, &clkinfo, sizeof(clkinfo))); 1226 } 1227