1 /* $NetBSD: kern_clock.c,v 1.96 2005/12/11 12:24:29 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2000, 2004 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 * This code is derived from software contributed to The NetBSD Foundation 11 * by Charles M. Hannum. 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 NetBSD 24 * Foundation, Inc. and its contributors. 25 * 4. Neither the name of The NetBSD Foundation nor the names of its 26 * contributors may be used to endorse or promote products derived 27 * from this software without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 30 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 31 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 32 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 33 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 34 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 35 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 37 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 39 * POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 /*- 43 * Copyright (c) 1982, 1986, 1991, 1993 44 * The Regents of the University of California. All rights reserved. 45 * (c) UNIX System Laboratories, Inc. 46 * All or some portions of this file are derived from material licensed 47 * to the University of California by American Telephone and Telegraph 48 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 49 * the permission of UNIX System Laboratories, Inc. 50 * 51 * Redistribution and use in source and binary forms, with or without 52 * modification, are permitted provided that the following conditions 53 * are met: 54 * 1. Redistributions of source code must retain the above copyright 55 * notice, this list of conditions and the following disclaimer. 56 * 2. Redistributions in binary form must reproduce the above copyright 57 * notice, this list of conditions and the following disclaimer in the 58 * documentation and/or other materials provided with the distribution. 59 * 3. Neither the name of the University nor the names of its contributors 60 * may be used to endorse or promote products derived from this software 61 * without specific prior written permission. 62 * 63 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 64 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 65 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 66 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 67 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 68 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 69 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 70 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 71 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 72 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 73 * SUCH DAMAGE. 74 * 75 * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 76 */ 77 78 #include <sys/cdefs.h> 79 __KERNEL_RCSID(0, "$NetBSD: kern_clock.c,v 1.96 2005/12/11 12:24:29 christos Exp $"); 80 81 #include "opt_ntp.h" 82 #include "opt_multiprocessor.h" 83 #include "opt_perfctrs.h" 84 85 #include <sys/param.h> 86 #include <sys/systm.h> 87 #include <sys/callout.h> 88 #include <sys/kernel.h> 89 #include <sys/proc.h> 90 #include <sys/resourcevar.h> 91 #include <sys/signalvar.h> 92 #include <sys/sysctl.h> 93 #include <sys/timex.h> 94 #include <sys/sched.h> 95 #include <sys/time.h> 96 97 #include <machine/cpu.h> 98 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 99 #include <machine/intr.h> 100 #endif 101 102 #ifdef GPROF 103 #include <sys/gmon.h> 104 #endif 105 106 /* 107 * Clock handling routines. 108 * 109 * This code is written to operate with two timers that run independently of 110 * each other. The main clock, running hz times per second, is used to keep 111 * track of real time. The second timer handles kernel and user profiling, 112 * and does resource use estimation. If the second timer is programmable, 113 * it is randomized to avoid aliasing between the two clocks. For example, 114 * the randomization prevents an adversary from always giving up the CPU 115 * just before its quantum expires. Otherwise, it would never accumulate 116 * CPU ticks. The mean frequency of the second timer is stathz. 117 * 118 * If no second timer exists, stathz will be zero; in this case we drive 119 * profiling and statistics off the main clock. This WILL NOT be accurate; 120 * do not do it unless absolutely necessary. 121 * 122 * The statistics clock may (or may not) be run at a higher rate while 123 * profiling. This profile clock runs at profhz. We require that profhz 124 * be an integral multiple of stathz. 125 * 126 * If the statistics clock is running fast, it must be divided by the ratio 127 * profhz/stathz for statistics. (For profiling, every tick counts.) 128 */ 129 130 #ifdef NTP /* NTP phase-locked loop in kernel */ 131 /* 132 * Phase/frequency-lock loop (PLL/FLL) definitions 133 * 134 * The following variables are read and set by the ntp_adjtime() system 135 * call. 136 * 137 * time_state shows the state of the system clock, with values defined 138 * in the timex.h header file. 139 * 140 * time_status shows the status of the system clock, with bits defined 141 * in the timex.h header file. 142 * 143 * time_offset is used by the PLL/FLL to adjust the system time in small 144 * increments. 145 * 146 * time_constant determines the bandwidth or "stiffness" of the PLL. 147 * 148 * time_tolerance determines maximum frequency error or tolerance of the 149 * CPU clock oscillator and is a property of the architecture; however, 150 * in principle it could change as result of the presence of external 151 * discipline signals, for instance. 152 * 153 * time_precision is usually equal to the kernel tick variable; however, 154 * in cases where a precision clock counter or external clock is 155 * available, the resolution can be much less than this and depend on 156 * whether the external clock is working or not. 157 * 158 * time_maxerror is initialized by a ntp_adjtime() call and increased by 159 * the kernel once each second to reflect the maximum error bound 160 * growth. 161 * 162 * time_esterror is set and read by the ntp_adjtime() call, but 163 * otherwise not used by the kernel. 164 */ 165 int time_state = TIME_OK; /* clock state */ 166 int time_status = STA_UNSYNC; /* clock status bits */ 167 long time_offset = 0; /* time offset (us) */ 168 long time_constant = 0; /* pll time constant */ 169 long time_tolerance = MAXFREQ; /* frequency tolerance (scaled ppm) */ 170 long time_precision = 1; /* clock precision (us) */ 171 long time_maxerror = MAXPHASE; /* maximum error (us) */ 172 long time_esterror = MAXPHASE; /* estimated error (us) */ 173 174 /* 175 * The following variables establish the state of the PLL/FLL and the 176 * residual time and frequency offset of the local clock. The scale 177 * factors are defined in the timex.h header file. 178 * 179 * time_phase and time_freq are the phase increment and the frequency 180 * increment, respectively, of the kernel time variable. 181 * 182 * time_freq is set via ntp_adjtime() from a value stored in a file when 183 * the synchronization daemon is first started. Its value is retrieved 184 * via ntp_adjtime() and written to the file about once per hour by the 185 * daemon. 186 * 187 * time_adj is the adjustment added to the value of tick at each timer 188 * interrupt and is recomputed from time_phase and time_freq at each 189 * seconds rollover. 190 * 191 * time_reftime is the second's portion of the system time at the last 192 * call to ntp_adjtime(). It is used to adjust the time_freq variable 193 * and to increase the time_maxerror as the time since last update 194 * increases. 195 */ 196 long time_phase = 0; /* phase offset (scaled us) */ 197 long time_freq = 0; /* frequency offset (scaled ppm) */ 198 long time_adj = 0; /* tick adjust (scaled 1 / hz) */ 199 long time_reftime = 0; /* time at last adjustment (s) */ 200 201 #ifdef PPS_SYNC 202 /* 203 * The following variables are used only if the kernel PPS discipline 204 * code is configured (PPS_SYNC). The scale factors are defined in the 205 * timex.h header file. 206 * 207 * pps_time contains the time at each calibration interval, as read by 208 * microtime(). pps_count counts the seconds of the calibration 209 * interval, the duration of which is nominally pps_shift in powers of 210 * two. 211 * 212 * pps_offset is the time offset produced by the time median filter 213 * pps_tf[], while pps_jitter is the dispersion (jitter) measured by 214 * this filter. 215 * 216 * pps_freq is the frequency offset produced by the frequency median 217 * filter pps_ff[], while pps_stabil is the dispersion (wander) measured 218 * by this filter. 219 * 220 * pps_usec is latched from a high resolution counter or external clock 221 * at pps_time. Here we want the hardware counter contents only, not the 222 * contents plus the time_tv.usec as usual. 223 * 224 * pps_valid counts the number of seconds since the last PPS update. It 225 * is used as a watchdog timer to disable the PPS discipline should the 226 * PPS signal be lost. 227 * 228 * pps_glitch counts the number of seconds since the beginning of an 229 * offset burst more than tick/2 from current nominal offset. It is used 230 * mainly to suppress error bursts due to priority conflicts between the 231 * PPS interrupt and timer interrupt. 232 * 233 * pps_intcnt counts the calibration intervals for use in the interval- 234 * adaptation algorithm. It's just too complicated for words. 235 * 236 * pps_kc_hardpps_source contains an arbitrary value that uniquely 237 * identifies the currently bound source of the PPS signal, or NULL 238 * if no source is bound. 239 * 240 * pps_kc_hardpps_mode indicates which transitions, if any, of the PPS 241 * signal should be reported. 242 */ 243 struct timeval pps_time; /* kernel time at last interval */ 244 long pps_tf[] = {0, 0, 0}; /* pps time offset median filter (us) */ 245 long pps_offset = 0; /* pps time offset (us) */ 246 long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */ 247 long pps_ff[] = {0, 0, 0}; /* pps frequency offset median filter */ 248 long pps_freq = 0; /* frequency offset (scaled ppm) */ 249 long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */ 250 long pps_usec = 0; /* microsec counter at last interval */ 251 long pps_valid = PPS_VALID; /* pps signal watchdog counter */ 252 int pps_glitch = 0; /* pps signal glitch counter */ 253 int pps_count = 0; /* calibration interval counter (s) */ 254 int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */ 255 int pps_intcnt = 0; /* intervals at current duration */ 256 void *pps_kc_hardpps_source = NULL; /* current PPS supplier's identifier */ 257 int pps_kc_hardpps_mode = 0; /* interesting edges of PPS signal */ 258 259 /* 260 * PPS signal quality monitors 261 * 262 * pps_jitcnt counts the seconds that have been discarded because the 263 * jitter measured by the time median filter exceeds the limit MAXTIME 264 * (100 us). 265 * 266 * pps_calcnt counts the frequency calibration intervals, which are 267 * variable from 4 s to 256 s. 268 * 269 * pps_errcnt counts the calibration intervals which have been discarded 270 * because the wander exceeds the limit MAXFREQ (100 ppm) or where the 271 * calibration interval jitter exceeds two ticks. 272 * 273 * pps_stbcnt counts the calibration intervals that have been discarded 274 * because the frequency wander exceeds the limit MAXFREQ / 4 (25 us). 275 */ 276 long pps_jitcnt = 0; /* jitter limit exceeded */ 277 long pps_calcnt = 0; /* calibration intervals */ 278 long pps_errcnt = 0; /* calibration errors */ 279 long pps_stbcnt = 0; /* stability limit exceeded */ 280 #endif /* PPS_SYNC */ 281 282 #ifdef EXT_CLOCK 283 /* 284 * External clock definitions 285 * 286 * The following definitions and declarations are used only if an 287 * external clock is configured on the system. 288 */ 289 #define CLOCK_INTERVAL 30 /* CPU clock update interval (s) */ 290 291 /* 292 * The clock_count variable is set to CLOCK_INTERVAL at each PPS 293 * interrupt and decremented once each second. 294 */ 295 int clock_count = 0; /* CPU clock counter */ 296 297 #ifdef HIGHBALL 298 /* 299 * The clock_offset and clock_cpu variables are used by the HIGHBALL 300 * interface. The clock_offset variable defines the offset between 301 * system time and the HIGBALL counters. The clock_cpu variable contains 302 * the offset between the system clock and the HIGHBALL clock for use in 303 * disciplining the kernel time variable. 304 */ 305 extern struct timeval clock_offset; /* Highball clock offset */ 306 long clock_cpu = 0; /* CPU clock adjust */ 307 #endif /* HIGHBALL */ 308 #endif /* EXT_CLOCK */ 309 #endif /* NTP */ 310 311 312 /* 313 * Bump a timeval by a small number of usec's. 314 */ 315 #define BUMPTIME(t, usec) { \ 316 volatile struct timeval *tp = (t); \ 317 long us; \ 318 \ 319 tp->tv_usec = us = tp->tv_usec + (usec); \ 320 if (us >= 1000000) { \ 321 tp->tv_usec = us - 1000000; \ 322 tp->tv_sec++; \ 323 } \ 324 } 325 326 int stathz; 327 int profhz; 328 int profsrc; 329 int schedhz; 330 int profprocs; 331 int hardclock_ticks; 332 static int statscheddiv; /* stat => sched divider (used if schedhz == 0) */ 333 static int psdiv; /* prof => stat divider */ 334 int psratio; /* ratio: prof / stat */ 335 int tickfix, tickfixinterval; /* used if tick not really integral */ 336 #ifndef NTP 337 static int tickfixcnt; /* accumulated fractional error */ 338 #else 339 int fixtick; /* used by NTP for same */ 340 int shifthz; 341 #endif 342 343 /* 344 * We might want ldd to load the both words from time at once. 345 * To succeed we need to be quadword aligned. 346 * The sparc already does that, and that it has worked so far is a fluke. 347 */ 348 volatile struct timeval time __attribute__((__aligned__(__alignof__(quad_t)))); 349 volatile struct timeval mono_time; 350 351 void *softclock_si; 352 353 /* 354 * Initialize clock frequencies and start both clocks running. 355 */ 356 void 357 initclocks(void) 358 { 359 int i; 360 361 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 362 softclock_si = softintr_establish(IPL_SOFTCLOCK, softclock, NULL); 363 if (softclock_si == NULL) 364 panic("initclocks: unable to register softclock intr"); 365 #endif 366 367 /* 368 * Set divisors to 1 (normal case) and let the machine-specific 369 * code do its bit. 370 */ 371 psdiv = 1; 372 cpu_initclocks(); 373 374 /* 375 * Compute profhz/stathz/rrticks, and fix profhz if needed. 376 */ 377 i = stathz ? stathz : hz; 378 if (profhz == 0) 379 profhz = i; 380 psratio = profhz / i; 381 rrticks = hz / 10; 382 if (schedhz == 0) { 383 /* 16Hz is best */ 384 statscheddiv = i / 16; 385 if (statscheddiv <= 0) 386 panic("statscheddiv"); 387 } 388 389 #ifdef NTP 390 switch (hz) { 391 case 1: 392 shifthz = SHIFT_SCALE - 0; 393 break; 394 case 2: 395 shifthz = SHIFT_SCALE - 1; 396 break; 397 case 4: 398 shifthz = SHIFT_SCALE - 2; 399 break; 400 case 8: 401 shifthz = SHIFT_SCALE - 3; 402 break; 403 case 16: 404 shifthz = SHIFT_SCALE - 4; 405 break; 406 case 32: 407 shifthz = SHIFT_SCALE - 5; 408 break; 409 case 50: 410 case 60: 411 case 64: 412 shifthz = SHIFT_SCALE - 6; 413 break; 414 case 96: 415 case 100: 416 case 128: 417 shifthz = SHIFT_SCALE - 7; 418 break; 419 case 256: 420 shifthz = SHIFT_SCALE - 8; 421 break; 422 case 512: 423 shifthz = SHIFT_SCALE - 9; 424 break; 425 case 1000: 426 case 1024: 427 shifthz = SHIFT_SCALE - 10; 428 break; 429 case 1200: 430 case 2048: 431 shifthz = SHIFT_SCALE - 11; 432 break; 433 case 4096: 434 shifthz = SHIFT_SCALE - 12; 435 break; 436 case 8192: 437 shifthz = SHIFT_SCALE - 13; 438 break; 439 case 16384: 440 shifthz = SHIFT_SCALE - 14; 441 break; 442 case 32768: 443 shifthz = SHIFT_SCALE - 15; 444 break; 445 case 65536: 446 shifthz = SHIFT_SCALE - 16; 447 break; 448 default: 449 panic("weird hz"); 450 } 451 if (fixtick == 0) { 452 /* 453 * Give MD code a chance to set this to a better 454 * value; but, if it doesn't, we should. 455 */ 456 fixtick = (1000000 - (hz*tick)); 457 } 458 #endif 459 } 460 461 /* 462 * The real-time timer, interrupting hz times per second. 463 */ 464 void 465 hardclock(struct clockframe *frame) 466 { 467 struct lwp *l; 468 struct proc *p; 469 int delta; 470 extern int tickdelta; 471 extern long timedelta; 472 struct cpu_info *ci = curcpu(); 473 struct ptimer *pt; 474 #ifdef NTP 475 int time_update; 476 int ltemp; 477 #endif 478 479 l = curlwp; 480 if (l) { 481 p = l->l_proc; 482 /* 483 * Run current process's virtual and profile time, as needed. 484 */ 485 if (CLKF_USERMODE(frame) && p->p_timers && 486 (pt = LIST_FIRST(&p->p_timers->pts_virtual)) != NULL) 487 if (itimerdecr(pt, tick) == 0) 488 itimerfire(pt); 489 if (p->p_timers && 490 (pt = LIST_FIRST(&p->p_timers->pts_prof)) != NULL) 491 if (itimerdecr(pt, tick) == 0) 492 itimerfire(pt); 493 } 494 495 /* 496 * If no separate statistics clock is available, run it from here. 497 */ 498 if (stathz == 0) 499 statclock(frame); 500 if ((--ci->ci_schedstate.spc_rrticks) <= 0) 501 roundrobin(ci); 502 503 #if defined(MULTIPROCESSOR) 504 /* 505 * If we are not the primary CPU, we're not allowed to do 506 * any more work. 507 */ 508 if (CPU_IS_PRIMARY(ci) == 0) 509 return; 510 #endif 511 512 /* 513 * Increment the time-of-day. The increment is normally just 514 * ``tick''. If the machine is one which has a clock frequency 515 * such that ``hz'' would not divide the second evenly into 516 * milliseconds, a periodic adjustment must be applied. Finally, 517 * if we are still adjusting the time (see adjtime()), 518 * ``tickdelta'' may also be added in. 519 */ 520 hardclock_ticks++; 521 delta = tick; 522 523 #ifndef NTP 524 if (tickfix) { 525 tickfixcnt += tickfix; 526 if (tickfixcnt >= tickfixinterval) { 527 delta++; 528 tickfixcnt -= tickfixinterval; 529 } 530 } 531 #endif /* !NTP */ 532 /* Imprecise 4bsd adjtime() handling */ 533 if (timedelta != 0) { 534 delta += tickdelta; 535 timedelta -= tickdelta; 536 } 537 538 #ifdef notyet 539 microset(); 540 #endif 541 542 #ifndef NTP 543 BUMPTIME(&time, delta); /* XXX Now done using NTP code below */ 544 #endif 545 BUMPTIME(&mono_time, delta); 546 547 #ifdef NTP 548 time_update = delta; 549 550 /* 551 * Compute the phase adjustment. If the low-order bits 552 * (time_phase) of the update overflow, bump the high-order bits 553 * (time_update). 554 */ 555 time_phase += time_adj; 556 if (time_phase <= -FINEUSEC) { 557 ltemp = -time_phase >> SHIFT_SCALE; 558 time_phase += ltemp << SHIFT_SCALE; 559 time_update -= ltemp; 560 } else if (time_phase >= FINEUSEC) { 561 ltemp = time_phase >> SHIFT_SCALE; 562 time_phase -= ltemp << SHIFT_SCALE; 563 time_update += ltemp; 564 } 565 566 #ifdef HIGHBALL 567 /* 568 * If the HIGHBALL board is installed, we need to adjust the 569 * external clock offset in order to close the hardware feedback 570 * loop. This will adjust the external clock phase and frequency 571 * in small amounts. The additional phase noise and frequency 572 * wander this causes should be minimal. We also need to 573 * discipline the kernel time variable, since the PLL is used to 574 * discipline the external clock. If the Highball board is not 575 * present, we discipline kernel time with the PLL as usual. We 576 * assume that the external clock phase adjustment (time_update) 577 * and kernel phase adjustment (clock_cpu) are less than the 578 * value of tick. 579 */ 580 clock_offset.tv_usec += time_update; 581 if (clock_offset.tv_usec >= 1000000) { 582 clock_offset.tv_sec++; 583 clock_offset.tv_usec -= 1000000; 584 } 585 if (clock_offset.tv_usec < 0) { 586 clock_offset.tv_sec--; 587 clock_offset.tv_usec += 1000000; 588 } 589 time.tv_usec += clock_cpu; 590 clock_cpu = 0; 591 #else 592 time.tv_usec += time_update; 593 #endif /* HIGHBALL */ 594 595 /* 596 * On rollover of the second the phase adjustment to be used for 597 * the next second is calculated. Also, the maximum error is 598 * increased by the tolerance. If the PPS frequency discipline 599 * code is present, the phase is increased to compensate for the 600 * CPU clock oscillator frequency error. 601 * 602 * On a 32-bit machine and given parameters in the timex.h 603 * header file, the maximum phase adjustment is +-512 ms and 604 * maximum frequency offset is a tad less than) +-512 ppm. On a 605 * 64-bit machine, you shouldn't need to ask. 606 */ 607 if (time.tv_usec >= 1000000) { 608 time.tv_usec -= 1000000; 609 time.tv_sec++; 610 time_maxerror += time_tolerance >> SHIFT_USEC; 611 612 /* 613 * Leap second processing. If in leap-insert state at 614 * the end of the day, the system clock is set back one 615 * second; if in leap-delete state, the system clock is 616 * set ahead one second. The microtime() routine or 617 * external clock driver will insure that reported time 618 * is always monotonic. The ugly divides should be 619 * replaced. 620 */ 621 switch (time_state) { 622 case TIME_OK: 623 if (time_status & STA_INS) 624 time_state = TIME_INS; 625 else if (time_status & STA_DEL) 626 time_state = TIME_DEL; 627 break; 628 629 case TIME_INS: 630 if (time.tv_sec % 86400 == 0) { 631 time.tv_sec--; 632 time_state = TIME_OOP; 633 } 634 break; 635 636 case TIME_DEL: 637 if ((time.tv_sec + 1) % 86400 == 0) { 638 time.tv_sec++; 639 time_state = TIME_WAIT; 640 } 641 break; 642 643 case TIME_OOP: 644 time_state = TIME_WAIT; 645 break; 646 647 case TIME_WAIT: 648 if (!(time_status & (STA_INS | STA_DEL))) 649 time_state = TIME_OK; 650 break; 651 } 652 653 /* 654 * Compute the phase adjustment for the next second. In 655 * PLL mode, the offset is reduced by a fixed factor 656 * times the time constant. In FLL mode the offset is 657 * used directly. In either mode, the maximum phase 658 * adjustment for each second is clamped so as to spread 659 * the adjustment over not more than the number of 660 * seconds between updates. 661 */ 662 if (time_offset < 0) { 663 ltemp = -time_offset; 664 if (!(time_status & STA_FLL)) 665 ltemp >>= SHIFT_KG + time_constant; 666 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 667 ltemp = (MAXPHASE / MINSEC) << 668 SHIFT_UPDATE; 669 time_offset += ltemp; 670 time_adj = -ltemp << (shifthz - SHIFT_UPDATE); 671 } else if (time_offset > 0) { 672 ltemp = time_offset; 673 if (!(time_status & STA_FLL)) 674 ltemp >>= SHIFT_KG + time_constant; 675 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 676 ltemp = (MAXPHASE / MINSEC) << 677 SHIFT_UPDATE; 678 time_offset -= ltemp; 679 time_adj = ltemp << (shifthz - SHIFT_UPDATE); 680 } else 681 time_adj = 0; 682 683 /* 684 * Compute the frequency estimate and additional phase 685 * adjustment due to frequency error for the next 686 * second. When the PPS signal is engaged, gnaw on the 687 * watchdog counter and update the frequency computed by 688 * the pll and the PPS signal. 689 */ 690 #ifdef PPS_SYNC 691 pps_valid++; 692 if (pps_valid == PPS_VALID) { 693 pps_jitter = MAXTIME; 694 pps_stabil = MAXFREQ; 695 time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | 696 STA_PPSWANDER | STA_PPSERROR); 697 } 698 ltemp = time_freq + pps_freq; 699 #else 700 ltemp = time_freq; 701 #endif /* PPS_SYNC */ 702 703 if (ltemp < 0) 704 time_adj -= -ltemp >> (SHIFT_USEC - shifthz); 705 else 706 time_adj += ltemp >> (SHIFT_USEC - shifthz); 707 time_adj += (long)fixtick << shifthz; 708 709 /* 710 * When the CPU clock oscillator frequency is not a 711 * power of 2 in Hz, shifthz is only an approximate 712 * scale factor. 713 * 714 * To determine the adjustment, you can do the following: 715 * bc -q 716 * scale=24 717 * obase=2 718 * idealhz/realhz 719 * where `idealhz' is the next higher power of 2, and `realhz' 720 * is the actual value. You may need to factor this result 721 * into a sequence of 2 multipliers to get better precision. 722 * 723 * Likewise, the error can be calculated with (e.g. for 100Hz): 724 * bc -q 725 * scale=24 726 * ((1+2^-2+2^-5)*(1-2^-10)*realhz-idealhz)/idealhz 727 * (and then multiply by 1000000 to get ppm). 728 */ 729 switch (hz) { 730 case 60: 731 /* A factor of 1.000100010001 gives about 15ppm 732 error. */ 733 if (time_adj < 0) { 734 time_adj -= (-time_adj >> 4); 735 time_adj -= (-time_adj >> 8); 736 } else { 737 time_adj += (time_adj >> 4); 738 time_adj += (time_adj >> 8); 739 } 740 break; 741 742 case 96: 743 /* A factor of 1.0101010101 gives about 244ppm error. */ 744 if (time_adj < 0) { 745 time_adj -= (-time_adj >> 2); 746 time_adj -= (-time_adj >> 4) + (-time_adj >> 8); 747 } else { 748 time_adj += (time_adj >> 2); 749 time_adj += (time_adj >> 4) + (time_adj >> 8); 750 } 751 break; 752 753 case 50: 754 case 100: 755 /* A factor of 1.010001111010111 gives about 1ppm 756 error. */ 757 if (time_adj < 0) { 758 time_adj -= (-time_adj >> 2) + (-time_adj >> 5); 759 time_adj += (-time_adj >> 10); 760 } else { 761 time_adj += (time_adj >> 2) + (time_adj >> 5); 762 time_adj -= (time_adj >> 10); 763 } 764 break; 765 766 case 1000: 767 /* A factor of 1.000001100010100001 gives about 50ppm 768 error. */ 769 if (time_adj < 0) { 770 time_adj -= (-time_adj >> 6) + (-time_adj >> 11); 771 time_adj -= (-time_adj >> 7); 772 } else { 773 time_adj += (time_adj >> 6) + (time_adj >> 11); 774 time_adj += (time_adj >> 7); 775 } 776 break; 777 778 case 1200: 779 /* A factor of 1.1011010011100001 gives about 64ppm 780 error. */ 781 if (time_adj < 0) { 782 time_adj -= (-time_adj >> 1) + (-time_adj >> 6); 783 time_adj -= (-time_adj >> 3) + (-time_adj >> 10); 784 } else { 785 time_adj += (time_adj >> 1) + (time_adj >> 6); 786 time_adj += (time_adj >> 3) + (time_adj >> 10); 787 } 788 break; 789 } 790 791 #ifdef EXT_CLOCK 792 /* 793 * If an external clock is present, it is necessary to 794 * discipline the kernel time variable anyway, since not 795 * all system components use the microtime() interface. 796 * Here, the time offset between the external clock and 797 * kernel time variable is computed every so often. 798 */ 799 clock_count++; 800 if (clock_count > CLOCK_INTERVAL) { 801 clock_count = 0; 802 microtime(&clock_ext); 803 delta.tv_sec = clock_ext.tv_sec - time.tv_sec; 804 delta.tv_usec = clock_ext.tv_usec - 805 time.tv_usec; 806 if (delta.tv_usec < 0) 807 delta.tv_sec--; 808 if (delta.tv_usec >= 500000) { 809 delta.tv_usec -= 1000000; 810 delta.tv_sec++; 811 } 812 if (delta.tv_usec < -500000) { 813 delta.tv_usec += 1000000; 814 delta.tv_sec--; 815 } 816 if (delta.tv_sec > 0 || (delta.tv_sec == 0 && 817 delta.tv_usec > MAXPHASE) || 818 delta.tv_sec < -1 || (delta.tv_sec == -1 && 819 delta.tv_usec < -MAXPHASE)) { 820 time = clock_ext; 821 delta.tv_sec = 0; 822 delta.tv_usec = 0; 823 } 824 #ifdef HIGHBALL 825 clock_cpu = delta.tv_usec; 826 #else /* HIGHBALL */ 827 hardupdate(delta.tv_usec); 828 #endif /* HIGHBALL */ 829 } 830 #endif /* EXT_CLOCK */ 831 } 832 833 #endif /* NTP */ 834 835 /* 836 * Update real-time timeout queue. 837 * Process callouts at a very low CPU priority, so we don't keep the 838 * relatively high clock interrupt priority any longer than necessary. 839 */ 840 if (callout_hardclock()) { 841 if (CLKF_BASEPRI(frame)) { 842 /* 843 * Save the overhead of a software interrupt; 844 * it will happen as soon as we return, so do 845 * it now. 846 */ 847 spllowersoftclock(); 848 KERNEL_LOCK(LK_CANRECURSE|LK_EXCLUSIVE); 849 softclock(NULL); 850 KERNEL_UNLOCK(); 851 } else { 852 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 853 softintr_schedule(softclock_si); 854 #else 855 setsoftclock(); 856 #endif 857 } 858 } 859 } 860 861 /* 862 * Compute number of hz until specified time. Used to compute second 863 * argument to callout_reset() from an absolute time. 864 */ 865 int 866 hzto(struct timeval *tv) 867 { 868 unsigned long ticks; 869 long sec, usec; 870 int s; 871 872 /* 873 * If the number of usecs in the whole seconds part of the time 874 * difference fits in a long, then the total number of usecs will 875 * fit in an unsigned long. Compute the total and convert it to 876 * ticks, rounding up and adding 1 to allow for the current tick 877 * to expire. Rounding also depends on unsigned long arithmetic 878 * to avoid overflow. 879 * 880 * Otherwise, if the number of ticks in the whole seconds part of 881 * the time difference fits in a long, then convert the parts to 882 * ticks separately and add, using similar rounding methods and 883 * overflow avoidance. This method would work in the previous 884 * case, but it is slightly slower and assume that hz is integral. 885 * 886 * Otherwise, round the time difference down to the maximum 887 * representable value. 888 * 889 * If ints are 32-bit, then the maximum value for any timeout in 890 * 10ms ticks is 248 days. 891 */ 892 s = splclock(); 893 sec = tv->tv_sec - time.tv_sec; 894 usec = tv->tv_usec - time.tv_usec; 895 splx(s); 896 897 if (usec < 0) { 898 sec--; 899 usec += 1000000; 900 } 901 902 if (sec < 0 || (sec == 0 && usec <= 0)) { 903 /* 904 * Would expire now or in the past. Return 0 ticks. 905 * This is different from the legacy hzto() interface, 906 * and callers need to check for it. 907 */ 908 ticks = 0; 909 } else if (sec <= (LONG_MAX / 1000000)) 910 ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1)) 911 / tick) + 1; 912 else if (sec <= (LONG_MAX / hz)) 913 ticks = (sec * hz) + 914 (((unsigned long)usec + (tick - 1)) / tick) + 1; 915 else 916 ticks = LONG_MAX; 917 918 if (ticks > INT_MAX) 919 ticks = INT_MAX; 920 921 return ((int)ticks); 922 } 923 924 /* 925 * Start profiling on a process. 926 * 927 * Kernel profiling passes proc0 which never exits and hence 928 * keeps the profile clock running constantly. 929 */ 930 void 931 startprofclock(struct proc *p) 932 { 933 934 if ((p->p_flag & P_PROFIL) == 0) { 935 p->p_flag |= P_PROFIL; 936 /* 937 * This is only necessary if using the clock as the 938 * profiling source. 939 */ 940 if (++profprocs == 1 && stathz != 0) 941 psdiv = psratio; 942 } 943 } 944 945 /* 946 * Stop profiling on a process. 947 */ 948 void 949 stopprofclock(struct proc *p) 950 { 951 952 if (p->p_flag & P_PROFIL) { 953 p->p_flag &= ~P_PROFIL; 954 /* 955 * This is only necessary if using the clock as the 956 * profiling source. 957 */ 958 if (--profprocs == 0 && stathz != 0) 959 psdiv = 1; 960 } 961 } 962 963 #if defined(PERFCTRS) 964 /* 965 * Independent profiling "tick" in case we're using a separate 966 * clock or profiling event source. Currently, that's just 967 * performance counters--hence the wrapper. 968 */ 969 void 970 proftick(struct clockframe *frame) 971 { 972 #ifdef GPROF 973 struct gmonparam *g; 974 intptr_t i; 975 #endif 976 struct proc *p; 977 978 p = curproc; 979 if (CLKF_USERMODE(frame)) { 980 if (p->p_flag & P_PROFIL) 981 addupc_intr(p, CLKF_PC(frame)); 982 } else { 983 #ifdef GPROF 984 g = &_gmonparam; 985 if (g->state == GMON_PROF_ON) { 986 i = CLKF_PC(frame) - g->lowpc; 987 if (i < g->textsize) { 988 i /= HISTFRACTION * sizeof(*g->kcount); 989 g->kcount[i]++; 990 } 991 } 992 #endif 993 #ifdef PROC_PC 994 if (p && p->p_flag & P_PROFIL) 995 addupc_intr(p, PROC_PC(p)); 996 #endif 997 } 998 } 999 #endif 1000 1001 /* 1002 * Statistics clock. Grab profile sample, and if divider reaches 0, 1003 * do process and kernel statistics. 1004 */ 1005 void 1006 statclock(struct clockframe *frame) 1007 { 1008 #ifdef GPROF 1009 struct gmonparam *g; 1010 intptr_t i; 1011 #endif 1012 struct cpu_info *ci = curcpu(); 1013 struct schedstate_percpu *spc = &ci->ci_schedstate; 1014 struct lwp *l; 1015 struct proc *p; 1016 1017 /* 1018 * Notice changes in divisor frequency, and adjust clock 1019 * frequency accordingly. 1020 */ 1021 if (spc->spc_psdiv != psdiv) { 1022 spc->spc_psdiv = psdiv; 1023 spc->spc_pscnt = psdiv; 1024 if (psdiv == 1) { 1025 setstatclockrate(stathz); 1026 } else { 1027 setstatclockrate(profhz); 1028 } 1029 } 1030 l = curlwp; 1031 p = (l ? l->l_proc : 0); 1032 if (CLKF_USERMODE(frame)) { 1033 if (p->p_flag & P_PROFIL && profsrc == PROFSRC_CLOCK) 1034 addupc_intr(p, CLKF_PC(frame)); 1035 if (--spc->spc_pscnt > 0) 1036 return; 1037 /* 1038 * Came from user mode; CPU was in user state. 1039 * If this process is being profiled record the tick. 1040 */ 1041 p->p_uticks++; 1042 if (p->p_nice > NZERO) 1043 spc->spc_cp_time[CP_NICE]++; 1044 else 1045 spc->spc_cp_time[CP_USER]++; 1046 } else { 1047 #ifdef GPROF 1048 /* 1049 * Kernel statistics are just like addupc_intr, only easier. 1050 */ 1051 g = &_gmonparam; 1052 if (profsrc == PROFSRC_CLOCK && g->state == GMON_PROF_ON) { 1053 i = CLKF_PC(frame) - g->lowpc; 1054 if (i < g->textsize) { 1055 i /= HISTFRACTION * sizeof(*g->kcount); 1056 g->kcount[i]++; 1057 } 1058 } 1059 #endif 1060 #ifdef LWP_PC 1061 if (p && profsrc == PROFSRC_CLOCK && p->p_flag & P_PROFIL) 1062 addupc_intr(p, LWP_PC(l)); 1063 #endif 1064 if (--spc->spc_pscnt > 0) 1065 return; 1066 /* 1067 * Came from kernel mode, so we were: 1068 * - handling an interrupt, 1069 * - doing syscall or trap work on behalf of the current 1070 * user process, or 1071 * - spinning in the idle loop. 1072 * Whichever it is, charge the time as appropriate. 1073 * Note that we charge interrupts to the current process, 1074 * regardless of whether they are ``for'' that process, 1075 * so that we know how much of its real time was spent 1076 * in ``non-process'' (i.e., interrupt) work. 1077 */ 1078 if (CLKF_INTR(frame)) { 1079 if (p != NULL) 1080 p->p_iticks++; 1081 spc->spc_cp_time[CP_INTR]++; 1082 } else if (p != NULL) { 1083 p->p_sticks++; 1084 spc->spc_cp_time[CP_SYS]++; 1085 } else 1086 spc->spc_cp_time[CP_IDLE]++; 1087 } 1088 spc->spc_pscnt = psdiv; 1089 1090 if (l != NULL) { 1091 ++p->p_cpticks; 1092 /* 1093 * If no separate schedclock is provided, call it here 1094 * at about 16 Hz. 1095 */ 1096 if (schedhz == 0) 1097 if ((int)(--ci->ci_schedstate.spc_schedticks) <= 0) { 1098 schedclock(l); 1099 ci->ci_schedstate.spc_schedticks = statscheddiv; 1100 } 1101 } 1102 } 1103 1104 1105 #ifdef NTP /* NTP phase-locked loop in kernel */ 1106 1107 /* 1108 * hardupdate() - local clock update 1109 * 1110 * This routine is called by ntp_adjtime() to update the local clock 1111 * phase and frequency. The implementation is of an adaptive-parameter, 1112 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 1113 * time and frequency offset estimates for each call. If the kernel PPS 1114 * discipline code is configured (PPS_SYNC), the PPS signal itself 1115 * determines the new time offset, instead of the calling argument. 1116 * Presumably, calls to ntp_adjtime() occur only when the caller 1117 * believes the local clock is valid within some bound (+-128 ms with 1118 * NTP). If the caller's time is far different than the PPS time, an 1119 * argument will ensue, and it's not clear who will lose. 1120 * 1121 * For uncompensated quartz crystal oscillatores and nominal update 1122 * intervals less than 1024 s, operation should be in phase-lock mode 1123 * (STA_FLL = 0), where the loop is disciplined to phase. For update 1124 * intervals greater than thiss, operation should be in frequency-lock 1125 * mode (STA_FLL = 1), where the loop is disciplined to frequency. 1126 * 1127 * Note: splclock() is in effect. 1128 */ 1129 void 1130 hardupdate(long offset) 1131 { 1132 long ltemp, mtemp; 1133 1134 if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME)) 1135 return; 1136 ltemp = offset; 1137 #ifdef PPS_SYNC 1138 if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL) 1139 ltemp = pps_offset; 1140 #endif /* PPS_SYNC */ 1141 1142 /* 1143 * Scale the phase adjustment and clamp to the operating range. 1144 */ 1145 if (ltemp > MAXPHASE) 1146 time_offset = MAXPHASE << SHIFT_UPDATE; 1147 else if (ltemp < -MAXPHASE) 1148 time_offset = -(MAXPHASE << SHIFT_UPDATE); 1149 else 1150 time_offset = ltemp << SHIFT_UPDATE; 1151 1152 /* 1153 * Select whether the frequency is to be controlled and in which 1154 * mode (PLL or FLL). Clamp to the operating range. Ugly 1155 * multiply/divide should be replaced someday. 1156 */ 1157 if (time_status & STA_FREQHOLD || time_reftime == 0) 1158 time_reftime = time.tv_sec; 1159 mtemp = time.tv_sec - time_reftime; 1160 time_reftime = time.tv_sec; 1161 if (time_status & STA_FLL) { 1162 if (mtemp >= MINSEC) { 1163 ltemp = ((time_offset / mtemp) << (SHIFT_USEC - 1164 SHIFT_UPDATE)); 1165 if (ltemp < 0) 1166 time_freq -= -ltemp >> SHIFT_KH; 1167 else 1168 time_freq += ltemp >> SHIFT_KH; 1169 } 1170 } else { 1171 if (mtemp < MAXSEC) { 1172 ltemp *= mtemp; 1173 if (ltemp < 0) 1174 time_freq -= -ltemp >> (time_constant + 1175 time_constant + SHIFT_KF - 1176 SHIFT_USEC); 1177 else 1178 time_freq += ltemp >> (time_constant + 1179 time_constant + SHIFT_KF - 1180 SHIFT_USEC); 1181 } 1182 } 1183 if (time_freq > time_tolerance) 1184 time_freq = time_tolerance; 1185 else if (time_freq < -time_tolerance) 1186 time_freq = -time_tolerance; 1187 } 1188 1189 #ifdef PPS_SYNC 1190 /* 1191 * hardpps() - discipline CPU clock oscillator to external PPS signal 1192 * 1193 * This routine is called at each PPS interrupt in order to discipline 1194 * the CPU clock oscillator to the PPS signal. It measures the PPS phase 1195 * and leaves it in a handy spot for the hardclock() routine. It 1196 * integrates successive PPS phase differences and calculates the 1197 * frequency offset. This is used in hardclock() to discipline the CPU 1198 * clock oscillator so that intrinsic frequency error is cancelled out. 1199 * The code requires the caller to capture the time and hardware counter 1200 * value at the on-time PPS signal transition. 1201 * 1202 * Note that, on some Unix systems, this routine runs at an interrupt 1203 * priority level higher than the timer interrupt routine hardclock(). 1204 * Therefore, the variables used are distinct from the hardclock() 1205 * variables, except for certain exceptions: The PPS frequency pps_freq 1206 * and phase pps_offset variables are determined by this routine and 1207 * updated atomically. The time_tolerance variable can be considered a 1208 * constant, since it is infrequently changed, and then only when the 1209 * PPS signal is disabled. The watchdog counter pps_valid is updated 1210 * once per second by hardclock() and is atomically cleared in this 1211 * routine. 1212 */ 1213 void 1214 hardpps(struct timeval *tvp, /* time at PPS */ 1215 long usec /* hardware counter at PPS */) 1216 { 1217 long u_usec, v_usec, bigtick; 1218 long cal_sec, cal_usec; 1219 1220 /* 1221 * An occasional glitch can be produced when the PPS interrupt 1222 * occurs in the hardclock() routine before the time variable is 1223 * updated. Here the offset is discarded when the difference 1224 * between it and the last one is greater than tick/2, but not 1225 * if the interval since the first discard exceeds 30 s. 1226 */ 1227 time_status |= STA_PPSSIGNAL; 1228 time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); 1229 pps_valid = 0; 1230 u_usec = -tvp->tv_usec; 1231 if (u_usec < -500000) 1232 u_usec += 1000000; 1233 v_usec = pps_offset - u_usec; 1234 if (v_usec < 0) 1235 v_usec = -v_usec; 1236 if (v_usec > (tick >> 1)) { 1237 if (pps_glitch > MAXGLITCH) { 1238 pps_glitch = 0; 1239 pps_tf[2] = u_usec; 1240 pps_tf[1] = u_usec; 1241 } else { 1242 pps_glitch++; 1243 u_usec = pps_offset; 1244 } 1245 } else 1246 pps_glitch = 0; 1247 1248 /* 1249 * A three-stage median filter is used to help deglitch the pps 1250 * time. The median sample becomes the time offset estimate; the 1251 * difference between the other two samples becomes the time 1252 * dispersion (jitter) estimate. 1253 */ 1254 pps_tf[2] = pps_tf[1]; 1255 pps_tf[1] = pps_tf[0]; 1256 pps_tf[0] = u_usec; 1257 if (pps_tf[0] > pps_tf[1]) { 1258 if (pps_tf[1] > pps_tf[2]) { 1259 pps_offset = pps_tf[1]; /* 0 1 2 */ 1260 v_usec = pps_tf[0] - pps_tf[2]; 1261 } else if (pps_tf[2] > pps_tf[0]) { 1262 pps_offset = pps_tf[0]; /* 2 0 1 */ 1263 v_usec = pps_tf[2] - pps_tf[1]; 1264 } else { 1265 pps_offset = pps_tf[2]; /* 0 2 1 */ 1266 v_usec = pps_tf[0] - pps_tf[1]; 1267 } 1268 } else { 1269 if (pps_tf[1] < pps_tf[2]) { 1270 pps_offset = pps_tf[1]; /* 2 1 0 */ 1271 v_usec = pps_tf[2] - pps_tf[0]; 1272 } else if (pps_tf[2] < pps_tf[0]) { 1273 pps_offset = pps_tf[0]; /* 1 0 2 */ 1274 v_usec = pps_tf[1] - pps_tf[2]; 1275 } else { 1276 pps_offset = pps_tf[2]; /* 1 2 0 */ 1277 v_usec = pps_tf[1] - pps_tf[0]; 1278 } 1279 } 1280 if (v_usec > MAXTIME) 1281 pps_jitcnt++; 1282 v_usec = (v_usec << PPS_AVG) - pps_jitter; 1283 if (v_usec < 0) 1284 pps_jitter -= -v_usec >> PPS_AVG; 1285 else 1286 pps_jitter += v_usec >> PPS_AVG; 1287 if (pps_jitter > (MAXTIME >> 1)) 1288 time_status |= STA_PPSJITTER; 1289 1290 /* 1291 * During the calibration interval adjust the starting time when 1292 * the tick overflows. At the end of the interval compute the 1293 * duration of the interval and the difference of the hardware 1294 * counters at the beginning and end of the interval. This code 1295 * is deliciously complicated by the fact valid differences may 1296 * exceed the value of tick when using long calibration 1297 * intervals and small ticks. Note that the counter can be 1298 * greater than tick if caught at just the wrong instant, but 1299 * the values returned and used here are correct. 1300 */ 1301 bigtick = (long)tick << SHIFT_USEC; 1302 pps_usec -= pps_freq; 1303 if (pps_usec >= bigtick) 1304 pps_usec -= bigtick; 1305 if (pps_usec < 0) 1306 pps_usec += bigtick; 1307 pps_time.tv_sec++; 1308 pps_count++; 1309 if (pps_count < (1 << pps_shift)) 1310 return; 1311 pps_count = 0; 1312 pps_calcnt++; 1313 u_usec = usec << SHIFT_USEC; 1314 v_usec = pps_usec - u_usec; 1315 if (v_usec >= bigtick >> 1) 1316 v_usec -= bigtick; 1317 if (v_usec < -(bigtick >> 1)) 1318 v_usec += bigtick; 1319 if (v_usec < 0) 1320 v_usec = -(-v_usec >> pps_shift); 1321 else 1322 v_usec = v_usec >> pps_shift; 1323 pps_usec = u_usec; 1324 cal_sec = tvp->tv_sec; 1325 cal_usec = tvp->tv_usec; 1326 cal_sec -= pps_time.tv_sec; 1327 cal_usec -= pps_time.tv_usec; 1328 if (cal_usec < 0) { 1329 cal_usec += 1000000; 1330 cal_sec--; 1331 } 1332 pps_time = *tvp; 1333 1334 /* 1335 * Check for lost interrupts, noise, excessive jitter and 1336 * excessive frequency error. The number of timer ticks during 1337 * the interval may vary +-1 tick. Add to this a margin of one 1338 * tick for the PPS signal jitter and maximum frequency 1339 * deviation. If the limits are exceeded, the calibration 1340 * interval is reset to the minimum and we start over. 1341 */ 1342 u_usec = (long)tick << 1; 1343 if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec)) 1344 || (cal_sec == 0 && cal_usec < u_usec)) 1345 || v_usec > time_tolerance || v_usec < -time_tolerance) { 1346 pps_errcnt++; 1347 pps_shift = PPS_SHIFT; 1348 pps_intcnt = 0; 1349 time_status |= STA_PPSERROR; 1350 return; 1351 } 1352 1353 /* 1354 * A three-stage median filter is used to help deglitch the pps 1355 * frequency. The median sample becomes the frequency offset 1356 * estimate; the difference between the other two samples 1357 * becomes the frequency dispersion (stability) estimate. 1358 */ 1359 pps_ff[2] = pps_ff[1]; 1360 pps_ff[1] = pps_ff[0]; 1361 pps_ff[0] = v_usec; 1362 if (pps_ff[0] > pps_ff[1]) { 1363 if (pps_ff[1] > pps_ff[2]) { 1364 u_usec = pps_ff[1]; /* 0 1 2 */ 1365 v_usec = pps_ff[0] - pps_ff[2]; 1366 } else if (pps_ff[2] > pps_ff[0]) { 1367 u_usec = pps_ff[0]; /* 2 0 1 */ 1368 v_usec = pps_ff[2] - pps_ff[1]; 1369 } else { 1370 u_usec = pps_ff[2]; /* 0 2 1 */ 1371 v_usec = pps_ff[0] - pps_ff[1]; 1372 } 1373 } else { 1374 if (pps_ff[1] < pps_ff[2]) { 1375 u_usec = pps_ff[1]; /* 2 1 0 */ 1376 v_usec = pps_ff[2] - pps_ff[0]; 1377 } else if (pps_ff[2] < pps_ff[0]) { 1378 u_usec = pps_ff[0]; /* 1 0 2 */ 1379 v_usec = pps_ff[1] - pps_ff[2]; 1380 } else { 1381 u_usec = pps_ff[2]; /* 1 2 0 */ 1382 v_usec = pps_ff[1] - pps_ff[0]; 1383 } 1384 } 1385 1386 /* 1387 * Here the frequency dispersion (stability) is updated. If it 1388 * is less than one-fourth the maximum (MAXFREQ), the frequency 1389 * offset is updated as well, but clamped to the tolerance. It 1390 * will be processed later by the hardclock() routine. 1391 */ 1392 v_usec = (v_usec >> 1) - pps_stabil; 1393 if (v_usec < 0) 1394 pps_stabil -= -v_usec >> PPS_AVG; 1395 else 1396 pps_stabil += v_usec >> PPS_AVG; 1397 if (pps_stabil > MAXFREQ >> 2) { 1398 pps_stbcnt++; 1399 time_status |= STA_PPSWANDER; 1400 return; 1401 } 1402 if (time_status & STA_PPSFREQ) { 1403 if (u_usec < 0) { 1404 pps_freq -= -u_usec >> PPS_AVG; 1405 if (pps_freq < -time_tolerance) 1406 pps_freq = -time_tolerance; 1407 u_usec = -u_usec; 1408 } else { 1409 pps_freq += u_usec >> PPS_AVG; 1410 if (pps_freq > time_tolerance) 1411 pps_freq = time_tolerance; 1412 } 1413 } 1414 1415 /* 1416 * Here the calibration interval is adjusted. If the maximum 1417 * time difference is greater than tick / 4, reduce the interval 1418 * by half. If this is not the case for four consecutive 1419 * intervals, double the interval. 1420 */ 1421 if (u_usec << pps_shift > bigtick >> 2) { 1422 pps_intcnt = 0; 1423 if (pps_shift > PPS_SHIFT) 1424 pps_shift--; 1425 } else if (pps_intcnt >= 4) { 1426 pps_intcnt = 0; 1427 if (pps_shift < PPS_SHIFTMAX) 1428 pps_shift++; 1429 } else 1430 pps_intcnt++; 1431 } 1432 #endif /* PPS_SYNC */ 1433 #endif /* NTP */ 1434 1435 /* 1436 * XXX: Until all md code has it. 1437 */ 1438 struct timespec * 1439 nanotime(struct timespec *ts) 1440 { 1441 struct timeval tv; 1442 1443 microtime(&tv); 1444 TIMEVAL_TO_TIMESPEC(&tv, ts); 1445 return ts; 1446 } 1447