1 /* $NetBSD: kern_clock.c,v 1.114 2007/11/06 00:42:40 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2000, 2004, 2006, 2007 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 1.114 2007/11/06 00:42:40 ad 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 #include <sys/timetc.h> 97 #include <sys/cpu.h> 98 99 #ifdef GPROF 100 #include <sys/gmon.h> 101 #endif 102 103 /* 104 * Clock handling routines. 105 * 106 * This code is written to operate with two timers that run independently of 107 * each other. The main clock, running hz times per second, is used to keep 108 * track of real time. The second timer handles kernel and user profiling, 109 * and does resource use estimation. If the second timer is programmable, 110 * it is randomized to avoid aliasing between the two clocks. For example, 111 * the randomization prevents an adversary from always giving up the CPU 112 * just before its quantum expires. Otherwise, it would never accumulate 113 * CPU ticks. The mean frequency of the second timer is stathz. 114 * 115 * If no second timer exists, stathz will be zero; in this case we drive 116 * profiling and statistics off the main clock. This WILL NOT be accurate; 117 * do not do it unless absolutely necessary. 118 * 119 * The statistics clock may (or may not) be run at a higher rate while 120 * profiling. This profile clock runs at profhz. We require that profhz 121 * be an integral multiple of stathz. 122 * 123 * If the statistics clock is running fast, it must be divided by the ratio 124 * profhz/stathz for statistics. (For profiling, every tick counts.) 125 */ 126 127 #ifndef __HAVE_TIMECOUNTER 128 #ifdef NTP /* NTP phase-locked loop in kernel */ 129 /* 130 * Phase/frequency-lock loop (PLL/FLL) definitions 131 * 132 * The following variables are read and set by the ntp_adjtime() system 133 * call. 134 * 135 * time_state shows the state of the system clock, with values defined 136 * in the timex.h header file. 137 * 138 * time_status shows the status of the system clock, with bits defined 139 * in the timex.h header file. 140 * 141 * time_offset is used by the PLL/FLL to adjust the system time in small 142 * increments. 143 * 144 * time_constant determines the bandwidth or "stiffness" of the PLL. 145 * 146 * time_tolerance determines maximum frequency error or tolerance of the 147 * CPU clock oscillator and is a property of the architecture; however, 148 * in principle it could change as result of the presence of external 149 * discipline signals, for instance. 150 * 151 * time_precision is usually equal to the kernel tick variable; however, 152 * in cases where a precision clock counter or external clock is 153 * available, the resolution can be much less than this and depend on 154 * whether the external clock is working or not. 155 * 156 * time_maxerror is initialized by a ntp_adjtime() call and increased by 157 * the kernel once each second to reflect the maximum error bound 158 * growth. 159 * 160 * time_esterror is set and read by the ntp_adjtime() call, but 161 * otherwise not used by the kernel. 162 */ 163 int time_state = TIME_OK; /* clock state */ 164 int time_status = STA_UNSYNC; /* clock status bits */ 165 long time_offset = 0; /* time offset (us) */ 166 long time_constant = 0; /* pll time constant */ 167 long time_tolerance = MAXFREQ; /* frequency tolerance (scaled ppm) */ 168 long time_precision = 1; /* clock precision (us) */ 169 long time_maxerror = MAXPHASE; /* maximum error (us) */ 170 long time_esterror = MAXPHASE; /* estimated error (us) */ 171 172 /* 173 * The following variables establish the state of the PLL/FLL and the 174 * residual time and frequency offset of the local clock. The scale 175 * factors are defined in the timex.h header file. 176 * 177 * time_phase and time_freq are the phase increment and the frequency 178 * increment, respectively, of the kernel time variable. 179 * 180 * time_freq is set via ntp_adjtime() from a value stored in a file when 181 * the synchronization daemon is first started. Its value is retrieved 182 * via ntp_adjtime() and written to the file about once per hour by the 183 * daemon. 184 * 185 * time_adj is the adjustment added to the value of tick at each timer 186 * interrupt and is recomputed from time_phase and time_freq at each 187 * seconds rollover. 188 * 189 * time_reftime is the second's portion of the system time at the last 190 * call to ntp_adjtime(). It is used to adjust the time_freq variable 191 * and to increase the time_maxerror as the time since last update 192 * increases. 193 */ 194 long time_phase = 0; /* phase offset (scaled us) */ 195 long time_freq = 0; /* frequency offset (scaled ppm) */ 196 long time_adj = 0; /* tick adjust (scaled 1 / hz) */ 197 long time_reftime = 0; /* time at last adjustment (s) */ 198 199 #ifdef PPS_SYNC 200 /* 201 * The following variables are used only if the kernel PPS discipline 202 * code is configured (PPS_SYNC). The scale factors are defined in the 203 * timex.h header file. 204 * 205 * pps_time contains the time at each calibration interval, as read by 206 * microtime(). pps_count counts the seconds of the calibration 207 * interval, the duration of which is nominally pps_shift in powers of 208 * two. 209 * 210 * pps_offset is the time offset produced by the time median filter 211 * pps_tf[], while pps_jitter is the dispersion (jitter) measured by 212 * this filter. 213 * 214 * pps_freq is the frequency offset produced by the frequency median 215 * filter pps_ff[], while pps_stabil is the dispersion (wander) measured 216 * by this filter. 217 * 218 * pps_usec is latched from a high resolution counter or external clock 219 * at pps_time. Here we want the hardware counter contents only, not the 220 * contents plus the time_tv.usec as usual. 221 * 222 * pps_valid counts the number of seconds since the last PPS update. It 223 * is used as a watchdog timer to disable the PPS discipline should the 224 * PPS signal be lost. 225 * 226 * pps_glitch counts the number of seconds since the beginning of an 227 * offset burst more than tick/2 from current nominal offset. It is used 228 * mainly to suppress error bursts due to priority conflicts between the 229 * PPS interrupt and timer interrupt. 230 * 231 * pps_intcnt counts the calibration intervals for use in the interval- 232 * adaptation algorithm. It's just too complicated for words. 233 * 234 * pps_kc_hardpps_source contains an arbitrary value that uniquely 235 * identifies the currently bound source of the PPS signal, or NULL 236 * if no source is bound. 237 * 238 * pps_kc_hardpps_mode indicates which transitions, if any, of the PPS 239 * signal should be reported. 240 */ 241 struct timeval pps_time; /* kernel time at last interval */ 242 long pps_tf[] = {0, 0, 0}; /* pps time offset median filter (us) */ 243 long pps_offset = 0; /* pps time offset (us) */ 244 long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */ 245 long pps_ff[] = {0, 0, 0}; /* pps frequency offset median filter */ 246 long pps_freq = 0; /* frequency offset (scaled ppm) */ 247 long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */ 248 long pps_usec = 0; /* microsec counter at last interval */ 249 long pps_valid = PPS_VALID; /* pps signal watchdog counter */ 250 int pps_glitch = 0; /* pps signal glitch counter */ 251 int pps_count = 0; /* calibration interval counter (s) */ 252 int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */ 253 int pps_intcnt = 0; /* intervals at current duration */ 254 void *pps_kc_hardpps_source = NULL; /* current PPS supplier's identifier */ 255 int pps_kc_hardpps_mode = 0; /* interesting edges of PPS signal */ 256 257 /* 258 * PPS signal quality monitors 259 * 260 * pps_jitcnt counts the seconds that have been discarded because the 261 * jitter measured by the time median filter exceeds the limit MAXTIME 262 * (100 us). 263 * 264 * pps_calcnt counts the frequency calibration intervals, which are 265 * variable from 4 s to 256 s. 266 * 267 * pps_errcnt counts the calibration intervals which have been discarded 268 * because the wander exceeds the limit MAXFREQ (100 ppm) or where the 269 * calibration interval jitter exceeds two ticks. 270 * 271 * pps_stbcnt counts the calibration intervals that have been discarded 272 * because the frequency wander exceeds the limit MAXFREQ / 4 (25 us). 273 */ 274 long pps_jitcnt = 0; /* jitter limit exceeded */ 275 long pps_calcnt = 0; /* calibration intervals */ 276 long pps_errcnt = 0; /* calibration errors */ 277 long pps_stbcnt = 0; /* stability limit exceeded */ 278 #endif /* PPS_SYNC */ 279 280 #ifdef EXT_CLOCK 281 /* 282 * External clock definitions 283 * 284 * The following definitions and declarations are used only if an 285 * external clock is configured on the system. 286 */ 287 #define CLOCK_INTERVAL 30 /* CPU clock update interval (s) */ 288 289 /* 290 * The clock_count variable is set to CLOCK_INTERVAL at each PPS 291 * interrupt and decremented once each second. 292 */ 293 int clock_count = 0; /* CPU clock counter */ 294 295 #endif /* EXT_CLOCK */ 296 #endif /* NTP */ 297 298 /* 299 * Bump a timeval by a small number of usec's. 300 */ 301 #define BUMPTIME(t, usec) { \ 302 volatile struct timeval *tp = (t); \ 303 long us; \ 304 \ 305 tp->tv_usec = us = tp->tv_usec + (usec); \ 306 if (us >= 1000000) { \ 307 tp->tv_usec = us - 1000000; \ 308 tp->tv_sec++; \ 309 } \ 310 } 311 #endif /* !__HAVE_TIMECOUNTER */ 312 313 int stathz; 314 int profhz; 315 int profsrc; 316 int schedhz; 317 int profprocs; 318 int hardclock_ticks; 319 static int hardscheddiv; /* hard => sched divider (used if schedhz == 0) */ 320 static int psdiv; /* prof => stat divider */ 321 int psratio; /* ratio: prof / stat */ 322 #ifndef __HAVE_TIMECOUNTER 323 int tickfix, tickfixinterval; /* used if tick not really integral */ 324 #ifndef NTP 325 static int tickfixcnt; /* accumulated fractional error */ 326 #else 327 int fixtick; /* used by NTP for same */ 328 int shifthz; 329 #endif 330 331 /* 332 * We might want ldd to load the both words from time at once. 333 * To succeed we need to be quadword aligned. 334 * The sparc already does that, and that it has worked so far is a fluke. 335 */ 336 volatile struct timeval time __attribute__((__aligned__(__alignof__(quad_t)))); 337 volatile struct timeval mono_time; 338 #endif /* !__HAVE_TIMECOUNTER */ 339 340 #ifdef __HAVE_TIMECOUNTER 341 static u_int get_intr_timecount(struct timecounter *); 342 343 static struct timecounter intr_timecounter = { 344 get_intr_timecount, /* get_timecount */ 345 0, /* no poll_pps */ 346 ~0u, /* counter_mask */ 347 0, /* frequency */ 348 "clockinterrupt", /* name */ 349 0, /* quality - minimum implementation level for a clock */ 350 NULL, /* prev */ 351 NULL, /* next */ 352 }; 353 354 static u_int 355 get_intr_timecount(struct timecounter *tc) 356 { 357 358 return (u_int)hardclock_ticks; 359 } 360 #endif 361 362 /* 363 * Initialize clock frequencies and start both clocks running. 364 */ 365 void 366 initclocks(void) 367 { 368 int i; 369 370 /* 371 * Set divisors to 1 (normal case) and let the machine-specific 372 * code do its bit. 373 */ 374 psdiv = 1; 375 #ifdef __HAVE_TIMECOUNTER 376 /* 377 * provide minimum default time counter 378 * will only run at interrupt resolution 379 */ 380 intr_timecounter.tc_frequency = hz; 381 tc_init(&intr_timecounter); 382 #endif 383 cpu_initclocks(); 384 385 /* 386 * Compute profhz and stathz, fix profhz if needed. 387 */ 388 i = stathz ? stathz : hz; 389 if (profhz == 0) 390 profhz = i; 391 psratio = profhz / i; 392 if (schedhz == 0) { 393 /* 16Hz is best */ 394 hardscheddiv = hz / 16; 395 if (hardscheddiv <= 0) 396 panic("hardscheddiv"); 397 } 398 399 #ifndef __HAVE_TIMECOUNTER 400 #ifdef NTP 401 switch (hz) { 402 case 1: 403 shifthz = SHIFT_SCALE - 0; 404 break; 405 case 2: 406 shifthz = SHIFT_SCALE - 1; 407 break; 408 case 4: 409 shifthz = SHIFT_SCALE - 2; 410 break; 411 case 8: 412 shifthz = SHIFT_SCALE - 3; 413 break; 414 case 16: 415 shifthz = SHIFT_SCALE - 4; 416 break; 417 case 32: 418 shifthz = SHIFT_SCALE - 5; 419 break; 420 case 50: 421 case 60: 422 case 64: 423 shifthz = SHIFT_SCALE - 6; 424 break; 425 case 96: 426 case 100: 427 case 128: 428 shifthz = SHIFT_SCALE - 7; 429 break; 430 case 256: 431 shifthz = SHIFT_SCALE - 8; 432 break; 433 case 512: 434 shifthz = SHIFT_SCALE - 9; 435 break; 436 case 1000: 437 case 1024: 438 shifthz = SHIFT_SCALE - 10; 439 break; 440 case 1200: 441 case 2048: 442 shifthz = SHIFT_SCALE - 11; 443 break; 444 case 4096: 445 shifthz = SHIFT_SCALE - 12; 446 break; 447 case 8192: 448 shifthz = SHIFT_SCALE - 13; 449 break; 450 case 16384: 451 shifthz = SHIFT_SCALE - 14; 452 break; 453 case 32768: 454 shifthz = SHIFT_SCALE - 15; 455 break; 456 case 65536: 457 shifthz = SHIFT_SCALE - 16; 458 break; 459 default: 460 panic("weird hz"); 461 } 462 if (fixtick == 0) { 463 /* 464 * Give MD code a chance to set this to a better 465 * value; but, if it doesn't, we should. 466 */ 467 fixtick = (1000000 - (hz*tick)); 468 } 469 #endif /* NTP */ 470 #endif /* !__HAVE_TIMECOUNTER */ 471 } 472 473 /* 474 * The real-time timer, interrupting hz times per second. 475 */ 476 void 477 hardclock(struct clockframe *frame) 478 { 479 struct lwp *l; 480 struct proc *p; 481 struct cpu_info *ci = curcpu(); 482 struct ptimer *pt; 483 #ifndef __HAVE_TIMECOUNTER 484 int delta; 485 extern int tickdelta; 486 extern long timedelta; 487 #ifdef NTP 488 int time_update; 489 int ltemp; 490 #endif /* NTP */ 491 #endif /* __HAVE_TIMECOUNTER */ 492 493 l = ci->ci_data.cpu_onproc; 494 if (!CURCPU_IDLE_P()) { 495 p = l->l_proc; 496 /* 497 * Run current process's virtual and profile time, as needed. 498 */ 499 if (CLKF_USERMODE(frame) && p->p_timers && 500 (pt = LIST_FIRST(&p->p_timers->pts_virtual)) != NULL) 501 if (itimerdecr(pt, tick) == 0) 502 itimerfire(pt); 503 if (p->p_timers && 504 (pt = LIST_FIRST(&p->p_timers->pts_prof)) != NULL) 505 if (itimerdecr(pt, tick) == 0) 506 itimerfire(pt); 507 } 508 509 /* 510 * If no separate statistics clock is available, run it from here. 511 */ 512 if (stathz == 0) 513 statclock(frame); 514 /* 515 * If no separate schedclock is provided, call it here 516 * at about 16 Hz. 517 */ 518 if (schedhz == 0) { 519 if ((int)(--ci->ci_schedstate.spc_schedticks) <= 0) { 520 schedclock(l); 521 ci->ci_schedstate.spc_schedticks = hardscheddiv; 522 } 523 } 524 if ((--ci->ci_schedstate.spc_ticks) <= 0) 525 sched_tick(ci); 526 527 #if defined(MULTIPROCESSOR) 528 /* 529 * If we are not the primary CPU, we're not allowed to do 530 * any more work. 531 */ 532 if (CPU_IS_PRIMARY(ci) == 0) 533 return; 534 #endif 535 536 hardclock_ticks++; 537 538 #ifdef __HAVE_TIMECOUNTER 539 tc_ticktock(); 540 #else /* __HAVE_TIMECOUNTER */ 541 /* 542 * Increment the time-of-day. The increment is normally just 543 * ``tick''. If the machine is one which has a clock frequency 544 * such that ``hz'' would not divide the second evenly into 545 * milliseconds, a periodic adjustment must be applied. Finally, 546 * if we are still adjusting the time (see adjtime()), 547 * ``tickdelta'' may also be added in. 548 */ 549 delta = tick; 550 551 #ifndef NTP 552 if (tickfix) { 553 tickfixcnt += tickfix; 554 if (tickfixcnt >= tickfixinterval) { 555 delta++; 556 tickfixcnt -= tickfixinterval; 557 } 558 } 559 #endif /* !NTP */ 560 /* Imprecise 4bsd adjtime() handling */ 561 if (timedelta != 0) { 562 delta += tickdelta; 563 timedelta -= tickdelta; 564 } 565 566 #ifdef notyet 567 microset(); 568 #endif 569 570 #ifndef NTP 571 BUMPTIME(&time, delta); /* XXX Now done using NTP code below */ 572 #endif 573 BUMPTIME(&mono_time, delta); 574 575 #ifdef NTP 576 time_update = delta; 577 578 /* 579 * Compute the phase adjustment. If the low-order bits 580 * (time_phase) of the update overflow, bump the high-order bits 581 * (time_update). 582 */ 583 time_phase += time_adj; 584 if (time_phase <= -FINEUSEC) { 585 ltemp = -time_phase >> SHIFT_SCALE; 586 time_phase += ltemp << SHIFT_SCALE; 587 time_update -= ltemp; 588 } else if (time_phase >= FINEUSEC) { 589 ltemp = time_phase >> SHIFT_SCALE; 590 time_phase -= ltemp << SHIFT_SCALE; 591 time_update += ltemp; 592 } 593 time.tv_usec += time_update; 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 hardupdate(delta.tv_usec); 825 } 826 #endif /* EXT_CLOCK */ 827 } 828 829 #endif /* NTP */ 830 #endif /* !__HAVE_TIMECOUNTER */ 831 832 /* 833 * Update real-time timeout queue. Callouts are processed at a 834 * very low CPU priority, so we don't keep the relatively high 835 * clock interrupt priority any longer than necessary. 836 */ 837 callout_hardclock(); 838 } 839 840 /* 841 * Start profiling on a process. 842 * 843 * Kernel profiling passes proc0 which never exits and hence 844 * keeps the profile clock running constantly. 845 */ 846 void 847 startprofclock(struct proc *p) 848 { 849 850 KASSERT(mutex_owned(&p->p_stmutex)); 851 852 if ((p->p_stflag & PST_PROFIL) == 0) { 853 p->p_stflag |= PST_PROFIL; 854 /* 855 * This is only necessary if using the clock as the 856 * profiling source. 857 */ 858 if (++profprocs == 1 && stathz != 0) 859 psdiv = psratio; 860 } 861 } 862 863 /* 864 * Stop profiling on a process. 865 */ 866 void 867 stopprofclock(struct proc *p) 868 { 869 870 KASSERT(mutex_owned(&p->p_stmutex)); 871 872 if (p->p_stflag & PST_PROFIL) { 873 p->p_stflag &= ~PST_PROFIL; 874 /* 875 * This is only necessary if using the clock as the 876 * profiling source. 877 */ 878 if (--profprocs == 0 && stathz != 0) 879 psdiv = 1; 880 } 881 } 882 883 #if defined(PERFCTRS) 884 /* 885 * Independent profiling "tick" in case we're using a separate 886 * clock or profiling event source. Currently, that's just 887 * performance counters--hence the wrapper. 888 */ 889 void 890 proftick(struct clockframe *frame) 891 { 892 #ifdef GPROF 893 struct gmonparam *g; 894 intptr_t i; 895 #endif 896 struct lwp *l; 897 struct proc *p; 898 899 l = curcpu()->ci_data.cpu_onproc; 900 p = (l ? l->l_proc : NULL); 901 if (CLKF_USERMODE(frame)) { 902 mutex_spin_enter(&p->p_stmutex); 903 if (p->p_stflag & PST_PROFIL) 904 addupc_intr(l, CLKF_PC(frame)); 905 mutex_spin_exit(&p->p_stmutex); 906 } else { 907 #ifdef GPROF 908 g = &_gmonparam; 909 if (g->state == GMON_PROF_ON) { 910 i = CLKF_PC(frame) - g->lowpc; 911 if (i < g->textsize) { 912 i /= HISTFRACTION * sizeof(*g->kcount); 913 g->kcount[i]++; 914 } 915 } 916 #endif 917 #ifdef LWP_PC 918 if (p != NULL && (p->p_stflag & PST_PROFIL) != 0) 919 addupc_intr(l, LWP_PC(l)); 920 #endif 921 } 922 } 923 #endif 924 925 void 926 schedclock(struct lwp *l) 927 { 928 929 if ((l->l_flag & LW_IDLE) != 0) 930 return; 931 932 sched_schedclock(l); 933 } 934 935 /* 936 * Statistics clock. Grab profile sample, and if divider reaches 0, 937 * do process and kernel statistics. 938 */ 939 void 940 statclock(struct clockframe *frame) 941 { 942 #ifdef GPROF 943 struct gmonparam *g; 944 intptr_t i; 945 #endif 946 struct cpu_info *ci = curcpu(); 947 struct schedstate_percpu *spc = &ci->ci_schedstate; 948 struct proc *p; 949 struct lwp *l; 950 951 /* 952 * Notice changes in divisor frequency, and adjust clock 953 * frequency accordingly. 954 */ 955 if (spc->spc_psdiv != psdiv) { 956 spc->spc_psdiv = psdiv; 957 spc->spc_pscnt = psdiv; 958 if (psdiv == 1) { 959 setstatclockrate(stathz); 960 } else { 961 setstatclockrate(profhz); 962 } 963 } 964 l = ci->ci_data.cpu_onproc; 965 if ((l->l_flag & LW_IDLE) != 0) { 966 /* 967 * don't account idle lwps as swapper. 968 */ 969 p = NULL; 970 } else { 971 p = l->l_proc; 972 mutex_spin_enter(&p->p_stmutex); 973 } 974 975 if (CLKF_USERMODE(frame)) { 976 if ((p->p_stflag & PST_PROFIL) && profsrc == PROFSRC_CLOCK) 977 addupc_intr(l, CLKF_PC(frame)); 978 if (--spc->spc_pscnt > 0) { 979 mutex_spin_exit(&p->p_stmutex); 980 return; 981 } 982 983 /* 984 * Came from user mode; CPU was in user state. 985 * If this process is being profiled record the tick. 986 */ 987 p->p_uticks++; 988 if (p->p_nice > NZERO) 989 spc->spc_cp_time[CP_NICE]++; 990 else 991 spc->spc_cp_time[CP_USER]++; 992 } else { 993 #ifdef GPROF 994 /* 995 * Kernel statistics are just like addupc_intr, only easier. 996 */ 997 g = &_gmonparam; 998 if (profsrc == PROFSRC_CLOCK && g->state == GMON_PROF_ON) { 999 i = CLKF_PC(frame) - g->lowpc; 1000 if (i < g->textsize) { 1001 i /= HISTFRACTION * sizeof(*g->kcount); 1002 g->kcount[i]++; 1003 } 1004 } 1005 #endif 1006 #ifdef LWP_PC 1007 if (p != NULL && profsrc == PROFSRC_CLOCK && 1008 (p->p_stflag & PST_PROFIL)) { 1009 addupc_intr(l, LWP_PC(l)); 1010 } 1011 #endif 1012 if (--spc->spc_pscnt > 0) { 1013 if (p != NULL) 1014 mutex_spin_exit(&p->p_stmutex); 1015 return; 1016 } 1017 /* 1018 * Came from kernel mode, so we were: 1019 * - handling an interrupt, 1020 * - doing syscall or trap work on behalf of the current 1021 * user process, or 1022 * - spinning in the idle loop. 1023 * Whichever it is, charge the time as appropriate. 1024 * Note that we charge interrupts to the current process, 1025 * regardless of whether they are ``for'' that process, 1026 * so that we know how much of its real time was spent 1027 * in ``non-process'' (i.e., interrupt) work. 1028 */ 1029 if (CLKF_INTR(frame) || (curlwp->l_pflag & LP_INTR) != 0) { 1030 if (p != NULL) { 1031 p->p_iticks++; 1032 } 1033 spc->spc_cp_time[CP_INTR]++; 1034 } else if (p != NULL) { 1035 p->p_sticks++; 1036 spc->spc_cp_time[CP_SYS]++; 1037 } else { 1038 spc->spc_cp_time[CP_IDLE]++; 1039 } 1040 } 1041 spc->spc_pscnt = psdiv; 1042 1043 if (p != NULL) { 1044 ++l->l_cpticks; 1045 mutex_spin_exit(&p->p_stmutex); 1046 } 1047 } 1048 1049 #ifndef __HAVE_TIMECOUNTER 1050 #ifdef NTP /* NTP phase-locked loop in kernel */ 1051 /* 1052 * hardupdate() - local clock update 1053 * 1054 * This routine is called by ntp_adjtime() to update the local clock 1055 * phase and frequency. The implementation is of an adaptive-parameter, 1056 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 1057 * time and frequency offset estimates for each call. If the kernel PPS 1058 * discipline code is configured (PPS_SYNC), the PPS signal itself 1059 * determines the new time offset, instead of the calling argument. 1060 * Presumably, calls to ntp_adjtime() occur only when the caller 1061 * believes the local clock is valid within some bound (+-128 ms with 1062 * NTP). If the caller's time is far different than the PPS time, an 1063 * argument will ensue, and it's not clear who will lose. 1064 * 1065 * For uncompensated quartz crystal oscillatores and nominal update 1066 * intervals less than 1024 s, operation should be in phase-lock mode 1067 * (STA_FLL = 0), where the loop is disciplined to phase. For update 1068 * intervals greater than thiss, operation should be in frequency-lock 1069 * mode (STA_FLL = 1), where the loop is disciplined to frequency. 1070 * 1071 * Note: splclock() is in effect. 1072 */ 1073 void 1074 hardupdate(long offset) 1075 { 1076 long ltemp, mtemp; 1077 1078 if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME)) 1079 return; 1080 ltemp = offset; 1081 #ifdef PPS_SYNC 1082 if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL) 1083 ltemp = pps_offset; 1084 #endif /* PPS_SYNC */ 1085 1086 /* 1087 * Scale the phase adjustment and clamp to the operating range. 1088 */ 1089 if (ltemp > MAXPHASE) 1090 time_offset = MAXPHASE << SHIFT_UPDATE; 1091 else if (ltemp < -MAXPHASE) 1092 time_offset = -(MAXPHASE << SHIFT_UPDATE); 1093 else 1094 time_offset = ltemp << SHIFT_UPDATE; 1095 1096 /* 1097 * Select whether the frequency is to be controlled and in which 1098 * mode (PLL or FLL). Clamp to the operating range. Ugly 1099 * multiply/divide should be replaced someday. 1100 */ 1101 if (time_status & STA_FREQHOLD || time_reftime == 0) 1102 time_reftime = time.tv_sec; 1103 mtemp = time.tv_sec - time_reftime; 1104 time_reftime = time.tv_sec; 1105 if (time_status & STA_FLL) { 1106 if (mtemp >= MINSEC) { 1107 ltemp = ((time_offset / mtemp) << (SHIFT_USEC - 1108 SHIFT_UPDATE)); 1109 if (ltemp < 0) 1110 time_freq -= -ltemp >> SHIFT_KH; 1111 else 1112 time_freq += ltemp >> SHIFT_KH; 1113 } 1114 } else { 1115 if (mtemp < MAXSEC) { 1116 ltemp *= mtemp; 1117 if (ltemp < 0) 1118 time_freq -= -ltemp >> (time_constant + 1119 time_constant + SHIFT_KF - 1120 SHIFT_USEC); 1121 else 1122 time_freq += ltemp >> (time_constant + 1123 time_constant + SHIFT_KF - 1124 SHIFT_USEC); 1125 } 1126 } 1127 if (time_freq > time_tolerance) 1128 time_freq = time_tolerance; 1129 else if (time_freq < -time_tolerance) 1130 time_freq = -time_tolerance; 1131 } 1132 1133 #ifdef PPS_SYNC 1134 /* 1135 * hardpps() - discipline CPU clock oscillator to external PPS signal 1136 * 1137 * This routine is called at each PPS interrupt in order to discipline 1138 * the CPU clock oscillator to the PPS signal. It measures the PPS phase 1139 * and leaves it in a handy spot for the hardclock() routine. It 1140 * integrates successive PPS phase differences and calculates the 1141 * frequency offset. This is used in hardclock() to discipline the CPU 1142 * clock oscillator so that intrinsic frequency error is cancelled out. 1143 * The code requires the caller to capture the time and hardware counter 1144 * value at the on-time PPS signal transition. 1145 * 1146 * Note that, on some Unix systems, this routine runs at an interrupt 1147 * priority level higher than the timer interrupt routine hardclock(). 1148 * Therefore, the variables used are distinct from the hardclock() 1149 * variables, except for certain exceptions: The PPS frequency pps_freq 1150 * and phase pps_offset variables are determined by this routine and 1151 * updated atomically. The time_tolerance variable can be considered a 1152 * constant, since it is infrequently changed, and then only when the 1153 * PPS signal is disabled. The watchdog counter pps_valid is updated 1154 * once per second by hardclock() and is atomically cleared in this 1155 * routine. 1156 */ 1157 void 1158 hardpps(struct timeval *tvp, /* time at PPS */ 1159 long usec /* hardware counter at PPS */) 1160 { 1161 long u_usec, v_usec, bigtick; 1162 long cal_sec, cal_usec; 1163 1164 /* 1165 * An occasional glitch can be produced when the PPS interrupt 1166 * occurs in the hardclock() routine before the time variable is 1167 * updated. Here the offset is discarded when the difference 1168 * between it and the last one is greater than tick/2, but not 1169 * if the interval since the first discard exceeds 30 s. 1170 */ 1171 time_status |= STA_PPSSIGNAL; 1172 time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); 1173 pps_valid = 0; 1174 u_usec = -tvp->tv_usec; 1175 if (u_usec < -500000) 1176 u_usec += 1000000; 1177 v_usec = pps_offset - u_usec; 1178 if (v_usec < 0) 1179 v_usec = -v_usec; 1180 if (v_usec > (tick >> 1)) { 1181 if (pps_glitch > MAXGLITCH) { 1182 pps_glitch = 0; 1183 pps_tf[2] = u_usec; 1184 pps_tf[1] = u_usec; 1185 } else { 1186 pps_glitch++; 1187 u_usec = pps_offset; 1188 } 1189 } else 1190 pps_glitch = 0; 1191 1192 /* 1193 * A three-stage median filter is used to help deglitch the pps 1194 * time. The median sample becomes the time offset estimate; the 1195 * difference between the other two samples becomes the time 1196 * dispersion (jitter) estimate. 1197 */ 1198 pps_tf[2] = pps_tf[1]; 1199 pps_tf[1] = pps_tf[0]; 1200 pps_tf[0] = u_usec; 1201 if (pps_tf[0] > pps_tf[1]) { 1202 if (pps_tf[1] > pps_tf[2]) { 1203 pps_offset = pps_tf[1]; /* 0 1 2 */ 1204 v_usec = pps_tf[0] - pps_tf[2]; 1205 } else if (pps_tf[2] > pps_tf[0]) { 1206 pps_offset = pps_tf[0]; /* 2 0 1 */ 1207 v_usec = pps_tf[2] - pps_tf[1]; 1208 } else { 1209 pps_offset = pps_tf[2]; /* 0 2 1 */ 1210 v_usec = pps_tf[0] - pps_tf[1]; 1211 } 1212 } else { 1213 if (pps_tf[1] < pps_tf[2]) { 1214 pps_offset = pps_tf[1]; /* 2 1 0 */ 1215 v_usec = pps_tf[2] - pps_tf[0]; 1216 } else if (pps_tf[2] < pps_tf[0]) { 1217 pps_offset = pps_tf[0]; /* 1 0 2 */ 1218 v_usec = pps_tf[1] - pps_tf[2]; 1219 } else { 1220 pps_offset = pps_tf[2]; /* 1 2 0 */ 1221 v_usec = pps_tf[1] - pps_tf[0]; 1222 } 1223 } 1224 if (v_usec > MAXTIME) 1225 pps_jitcnt++; 1226 v_usec = (v_usec << PPS_AVG) - pps_jitter; 1227 if (v_usec < 0) 1228 pps_jitter -= -v_usec >> PPS_AVG; 1229 else 1230 pps_jitter += v_usec >> PPS_AVG; 1231 if (pps_jitter > (MAXTIME >> 1)) 1232 time_status |= STA_PPSJITTER; 1233 1234 /* 1235 * During the calibration interval adjust the starting time when 1236 * the tick overflows. At the end of the interval compute the 1237 * duration of the interval and the difference of the hardware 1238 * counters at the beginning and end of the interval. This code 1239 * is deliciously complicated by the fact valid differences may 1240 * exceed the value of tick when using long calibration 1241 * intervals and small ticks. Note that the counter can be 1242 * greater than tick if caught at just the wrong instant, but 1243 * the values returned and used here are correct. 1244 */ 1245 bigtick = (long)tick << SHIFT_USEC; 1246 pps_usec -= pps_freq; 1247 if (pps_usec >= bigtick) 1248 pps_usec -= bigtick; 1249 if (pps_usec < 0) 1250 pps_usec += bigtick; 1251 pps_time.tv_sec++; 1252 pps_count++; 1253 if (pps_count < (1 << pps_shift)) 1254 return; 1255 pps_count = 0; 1256 pps_calcnt++; 1257 u_usec = usec << SHIFT_USEC; 1258 v_usec = pps_usec - u_usec; 1259 if (v_usec >= bigtick >> 1) 1260 v_usec -= bigtick; 1261 if (v_usec < -(bigtick >> 1)) 1262 v_usec += bigtick; 1263 if (v_usec < 0) 1264 v_usec = -(-v_usec >> pps_shift); 1265 else 1266 v_usec = v_usec >> pps_shift; 1267 pps_usec = u_usec; 1268 cal_sec = tvp->tv_sec; 1269 cal_usec = tvp->tv_usec; 1270 cal_sec -= pps_time.tv_sec; 1271 cal_usec -= pps_time.tv_usec; 1272 if (cal_usec < 0) { 1273 cal_usec += 1000000; 1274 cal_sec--; 1275 } 1276 pps_time = *tvp; 1277 1278 /* 1279 * Check for lost interrupts, noise, excessive jitter and 1280 * excessive frequency error. The number of timer ticks during 1281 * the interval may vary +-1 tick. Add to this a margin of one 1282 * tick for the PPS signal jitter and maximum frequency 1283 * deviation. If the limits are exceeded, the calibration 1284 * interval is reset to the minimum and we start over. 1285 */ 1286 u_usec = (long)tick << 1; 1287 if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec)) 1288 || (cal_sec == 0 && cal_usec < u_usec)) 1289 || v_usec > time_tolerance || v_usec < -time_tolerance) { 1290 pps_errcnt++; 1291 pps_shift = PPS_SHIFT; 1292 pps_intcnt = 0; 1293 time_status |= STA_PPSERROR; 1294 return; 1295 } 1296 1297 /* 1298 * A three-stage median filter is used to help deglitch the pps 1299 * frequency. The median sample becomes the frequency offset 1300 * estimate; the difference between the other two samples 1301 * becomes the frequency dispersion (stability) estimate. 1302 */ 1303 pps_ff[2] = pps_ff[1]; 1304 pps_ff[1] = pps_ff[0]; 1305 pps_ff[0] = v_usec; 1306 if (pps_ff[0] > pps_ff[1]) { 1307 if (pps_ff[1] > pps_ff[2]) { 1308 u_usec = pps_ff[1]; /* 0 1 2 */ 1309 v_usec = pps_ff[0] - pps_ff[2]; 1310 } else if (pps_ff[2] > pps_ff[0]) { 1311 u_usec = pps_ff[0]; /* 2 0 1 */ 1312 v_usec = pps_ff[2] - pps_ff[1]; 1313 } else { 1314 u_usec = pps_ff[2]; /* 0 2 1 */ 1315 v_usec = pps_ff[0] - pps_ff[1]; 1316 } 1317 } else { 1318 if (pps_ff[1] < pps_ff[2]) { 1319 u_usec = pps_ff[1]; /* 2 1 0 */ 1320 v_usec = pps_ff[2] - pps_ff[0]; 1321 } else if (pps_ff[2] < pps_ff[0]) { 1322 u_usec = pps_ff[0]; /* 1 0 2 */ 1323 v_usec = pps_ff[1] - pps_ff[2]; 1324 } else { 1325 u_usec = pps_ff[2]; /* 1 2 0 */ 1326 v_usec = pps_ff[1] - pps_ff[0]; 1327 } 1328 } 1329 1330 /* 1331 * Here the frequency dispersion (stability) is updated. If it 1332 * is less than one-fourth the maximum (MAXFREQ), the frequency 1333 * offset is updated as well, but clamped to the tolerance. It 1334 * will be processed later by the hardclock() routine. 1335 */ 1336 v_usec = (v_usec >> 1) - pps_stabil; 1337 if (v_usec < 0) 1338 pps_stabil -= -v_usec >> PPS_AVG; 1339 else 1340 pps_stabil += v_usec >> PPS_AVG; 1341 if (pps_stabil > MAXFREQ >> 2) { 1342 pps_stbcnt++; 1343 time_status |= STA_PPSWANDER; 1344 return; 1345 } 1346 if (time_status & STA_PPSFREQ) { 1347 if (u_usec < 0) { 1348 pps_freq -= -u_usec >> PPS_AVG; 1349 if (pps_freq < -time_tolerance) 1350 pps_freq = -time_tolerance; 1351 u_usec = -u_usec; 1352 } else { 1353 pps_freq += u_usec >> PPS_AVG; 1354 if (pps_freq > time_tolerance) 1355 pps_freq = time_tolerance; 1356 } 1357 } 1358 1359 /* 1360 * Here the calibration interval is adjusted. If the maximum 1361 * time difference is greater than tick / 4, reduce the interval 1362 * by half. If this is not the case for four consecutive 1363 * intervals, double the interval. 1364 */ 1365 if (u_usec << pps_shift > bigtick >> 2) { 1366 pps_intcnt = 0; 1367 if (pps_shift > PPS_SHIFT) 1368 pps_shift--; 1369 } else if (pps_intcnt >= 4) { 1370 pps_intcnt = 0; 1371 if (pps_shift < PPS_SHIFTMAX) 1372 pps_shift++; 1373 } else 1374 pps_intcnt++; 1375 } 1376 #endif /* PPS_SYNC */ 1377 #endif /* NTP */ 1378 1379 /* timecounter compat functions */ 1380 void 1381 nanotime(struct timespec *ts) 1382 { 1383 struct timeval tv; 1384 1385 microtime(&tv); 1386 TIMEVAL_TO_TIMESPEC(&tv, ts); 1387 } 1388 1389 void 1390 getbinuptime(struct bintime *bt) 1391 { 1392 struct timeval tv; 1393 1394 microtime(&tv); 1395 timeval2bintime(&tv, bt); 1396 } 1397 1398 void 1399 nanouptime(struct timespec *tsp) 1400 { 1401 int s; 1402 1403 s = splclock(); 1404 TIMEVAL_TO_TIMESPEC(&mono_time, tsp); 1405 splx(s); 1406 } 1407 1408 void 1409 getnanouptime(struct timespec *tsp) 1410 { 1411 int s; 1412 1413 s = splclock(); 1414 TIMEVAL_TO_TIMESPEC(&mono_time, tsp); 1415 splx(s); 1416 } 1417 1418 void 1419 getmicrouptime(struct timeval *tvp) 1420 { 1421 int s; 1422 1423 s = splclock(); 1424 *tvp = mono_time; 1425 splx(s); 1426 } 1427 1428 void 1429 getnanotime(struct timespec *tsp) 1430 { 1431 int s; 1432 1433 s = splclock(); 1434 TIMEVAL_TO_TIMESPEC(&time, tsp); 1435 splx(s); 1436 } 1437 1438 void 1439 getmicrotime(struct timeval *tvp) 1440 { 1441 int s; 1442 1443 s = splclock(); 1444 *tvp = time; 1445 splx(s); 1446 } 1447 1448 u_int64_t 1449 tc_getfrequency(void) 1450 { 1451 return hz; 1452 } 1453 #endif /* !__HAVE_TIMECOUNTER */ 1454