1 /* $NetBSD: kern_clock.c,v 1.104 2006/11/01 10:17:58 yamt 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 1.104 2006/11/01 10:17:58 yamt 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 #ifdef __HAVE_TIMECOUNTER 97 #include <sys/timetc.h> 98 #endif 99 100 #include <machine/cpu.h> 101 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 102 #include <machine/intr.h> 103 #endif 104 105 #ifdef GPROF 106 #include <sys/gmon.h> 107 #endif 108 109 /* 110 * Clock handling routines. 111 * 112 * This code is written to operate with two timers that run independently of 113 * each other. The main clock, running hz times per second, is used to keep 114 * track of real time. The second timer handles kernel and user profiling, 115 * and does resource use estimation. If the second timer is programmable, 116 * it is randomized to avoid aliasing between the two clocks. For example, 117 * the randomization prevents an adversary from always giving up the CPU 118 * just before its quantum expires. Otherwise, it would never accumulate 119 * CPU ticks. The mean frequency of the second timer is stathz. 120 * 121 * If no second timer exists, stathz will be zero; in this case we drive 122 * profiling and statistics off the main clock. This WILL NOT be accurate; 123 * do not do it unless absolutely necessary. 124 * 125 * The statistics clock may (or may not) be run at a higher rate while 126 * profiling. This profile clock runs at profhz. We require that profhz 127 * be an integral multiple of stathz. 128 * 129 * If the statistics clock is running fast, it must be divided by the ratio 130 * profhz/stathz for statistics. (For profiling, every tick counts.) 131 */ 132 133 #ifndef __HAVE_TIMECOUNTER 134 #ifdef NTP /* NTP phase-locked loop in kernel */ 135 /* 136 * Phase/frequency-lock loop (PLL/FLL) definitions 137 * 138 * The following variables are read and set by the ntp_adjtime() system 139 * call. 140 * 141 * time_state shows the state of the system clock, with values defined 142 * in the timex.h header file. 143 * 144 * time_status shows the status of the system clock, with bits defined 145 * in the timex.h header file. 146 * 147 * time_offset is used by the PLL/FLL to adjust the system time in small 148 * increments. 149 * 150 * time_constant determines the bandwidth or "stiffness" of the PLL. 151 * 152 * time_tolerance determines maximum frequency error or tolerance of the 153 * CPU clock oscillator and is a property of the architecture; however, 154 * in principle it could change as result of the presence of external 155 * discipline signals, for instance. 156 * 157 * time_precision is usually equal to the kernel tick variable; however, 158 * in cases where a precision clock counter or external clock is 159 * available, the resolution can be much less than this and depend on 160 * whether the external clock is working or not. 161 * 162 * time_maxerror is initialized by a ntp_adjtime() call and increased by 163 * the kernel once each second to reflect the maximum error bound 164 * growth. 165 * 166 * time_esterror is set and read by the ntp_adjtime() call, but 167 * otherwise not used by the kernel. 168 */ 169 int time_state = TIME_OK; /* clock state */ 170 int time_status = STA_UNSYNC; /* clock status bits */ 171 long time_offset = 0; /* time offset (us) */ 172 long time_constant = 0; /* pll time constant */ 173 long time_tolerance = MAXFREQ; /* frequency tolerance (scaled ppm) */ 174 long time_precision = 1; /* clock precision (us) */ 175 long time_maxerror = MAXPHASE; /* maximum error (us) */ 176 long time_esterror = MAXPHASE; /* estimated error (us) */ 177 178 /* 179 * The following variables establish the state of the PLL/FLL and the 180 * residual time and frequency offset of the local clock. The scale 181 * factors are defined in the timex.h header file. 182 * 183 * time_phase and time_freq are the phase increment and the frequency 184 * increment, respectively, of the kernel time variable. 185 * 186 * time_freq is set via ntp_adjtime() from a value stored in a file when 187 * the synchronization daemon is first started. Its value is retrieved 188 * via ntp_adjtime() and written to the file about once per hour by the 189 * daemon. 190 * 191 * time_adj is the adjustment added to the value of tick at each timer 192 * interrupt and is recomputed from time_phase and time_freq at each 193 * seconds rollover. 194 * 195 * time_reftime is the second's portion of the system time at the last 196 * call to ntp_adjtime(). It is used to adjust the time_freq variable 197 * and to increase the time_maxerror as the time since last update 198 * increases. 199 */ 200 long time_phase = 0; /* phase offset (scaled us) */ 201 long time_freq = 0; /* frequency offset (scaled ppm) */ 202 long time_adj = 0; /* tick adjust (scaled 1 / hz) */ 203 long time_reftime = 0; /* time at last adjustment (s) */ 204 205 #ifdef PPS_SYNC 206 /* 207 * The following variables are used only if the kernel PPS discipline 208 * code is configured (PPS_SYNC). The scale factors are defined in the 209 * timex.h header file. 210 * 211 * pps_time contains the time at each calibration interval, as read by 212 * microtime(). pps_count counts the seconds of the calibration 213 * interval, the duration of which is nominally pps_shift in powers of 214 * two. 215 * 216 * pps_offset is the time offset produced by the time median filter 217 * pps_tf[], while pps_jitter is the dispersion (jitter) measured by 218 * this filter. 219 * 220 * pps_freq is the frequency offset produced by the frequency median 221 * filter pps_ff[], while pps_stabil is the dispersion (wander) measured 222 * by this filter. 223 * 224 * pps_usec is latched from a high resolution counter or external clock 225 * at pps_time. Here we want the hardware counter contents only, not the 226 * contents plus the time_tv.usec as usual. 227 * 228 * pps_valid counts the number of seconds since the last PPS update. It 229 * is used as a watchdog timer to disable the PPS discipline should the 230 * PPS signal be lost. 231 * 232 * pps_glitch counts the number of seconds since the beginning of an 233 * offset burst more than tick/2 from current nominal offset. It is used 234 * mainly to suppress error bursts due to priority conflicts between the 235 * PPS interrupt and timer interrupt. 236 * 237 * pps_intcnt counts the calibration intervals for use in the interval- 238 * adaptation algorithm. It's just too complicated for words. 239 * 240 * pps_kc_hardpps_source contains an arbitrary value that uniquely 241 * identifies the currently bound source of the PPS signal, or NULL 242 * if no source is bound. 243 * 244 * pps_kc_hardpps_mode indicates which transitions, if any, of the PPS 245 * signal should be reported. 246 */ 247 struct timeval pps_time; /* kernel time at last interval */ 248 long pps_tf[] = {0, 0, 0}; /* pps time offset median filter (us) */ 249 long pps_offset = 0; /* pps time offset (us) */ 250 long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */ 251 long pps_ff[] = {0, 0, 0}; /* pps frequency offset median filter */ 252 long pps_freq = 0; /* frequency offset (scaled ppm) */ 253 long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */ 254 long pps_usec = 0; /* microsec counter at last interval */ 255 long pps_valid = PPS_VALID; /* pps signal watchdog counter */ 256 int pps_glitch = 0; /* pps signal glitch counter */ 257 int pps_count = 0; /* calibration interval counter (s) */ 258 int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */ 259 int pps_intcnt = 0; /* intervals at current duration */ 260 void *pps_kc_hardpps_source = NULL; /* current PPS supplier's identifier */ 261 int pps_kc_hardpps_mode = 0; /* interesting edges of PPS signal */ 262 263 /* 264 * PPS signal quality monitors 265 * 266 * pps_jitcnt counts the seconds that have been discarded because the 267 * jitter measured by the time median filter exceeds the limit MAXTIME 268 * (100 us). 269 * 270 * pps_calcnt counts the frequency calibration intervals, which are 271 * variable from 4 s to 256 s. 272 * 273 * pps_errcnt counts the calibration intervals which have been discarded 274 * because the wander exceeds the limit MAXFREQ (100 ppm) or where the 275 * calibration interval jitter exceeds two ticks. 276 * 277 * pps_stbcnt counts the calibration intervals that have been discarded 278 * because the frequency wander exceeds the limit MAXFREQ / 4 (25 us). 279 */ 280 long pps_jitcnt = 0; /* jitter limit exceeded */ 281 long pps_calcnt = 0; /* calibration intervals */ 282 long pps_errcnt = 0; /* calibration errors */ 283 long pps_stbcnt = 0; /* stability limit exceeded */ 284 #endif /* PPS_SYNC */ 285 286 #ifdef EXT_CLOCK 287 /* 288 * External clock definitions 289 * 290 * The following definitions and declarations are used only if an 291 * external clock is configured on the system. 292 */ 293 #define CLOCK_INTERVAL 30 /* CPU clock update interval (s) */ 294 295 /* 296 * The clock_count variable is set to CLOCK_INTERVAL at each PPS 297 * interrupt and decremented once each second. 298 */ 299 int clock_count = 0; /* CPU clock counter */ 300 301 #ifdef HIGHBALL 302 /* 303 * The clock_offset and clock_cpu variables are used by the HIGHBALL 304 * interface. The clock_offset variable defines the offset between 305 * system time and the HIGBALL counters. The clock_cpu variable contains 306 * the offset between the system clock and the HIGHBALL clock for use in 307 * disciplining the kernel time variable. 308 */ 309 extern struct timeval clock_offset; /* Highball clock offset */ 310 long clock_cpu = 0; /* CPU clock adjust */ 311 #endif /* HIGHBALL */ 312 #endif /* EXT_CLOCK */ 313 #endif /* NTP */ 314 315 /* 316 * Bump a timeval by a small number of usec's. 317 */ 318 #define BUMPTIME(t, usec) { \ 319 volatile struct timeval *tp = (t); \ 320 long us; \ 321 \ 322 tp->tv_usec = us = tp->tv_usec + (usec); \ 323 if (us >= 1000000) { \ 324 tp->tv_usec = us - 1000000; \ 325 tp->tv_sec++; \ 326 } \ 327 } 328 #endif /* !__HAVE_TIMECOUNTER */ 329 330 int stathz; 331 int profhz; 332 int profsrc; 333 int schedhz; 334 int profprocs; 335 int hardclock_ticks; 336 static int statscheddiv; /* stat => sched divider (used if schedhz == 0) */ 337 static int psdiv; /* prof => stat divider */ 338 int psratio; /* ratio: prof / stat */ 339 #ifndef __HAVE_TIMECOUNTER 340 int tickfix, tickfixinterval; /* used if tick not really integral */ 341 #ifndef NTP 342 static int tickfixcnt; /* accumulated fractional error */ 343 #else 344 int fixtick; /* used by NTP for same */ 345 int shifthz; 346 #endif 347 348 /* 349 * We might want ldd to load the both words from time at once. 350 * To succeed we need to be quadword aligned. 351 * The sparc already does that, and that it has worked so far is a fluke. 352 */ 353 volatile struct timeval time __attribute__((__aligned__(__alignof__(quad_t)))); 354 volatile struct timeval mono_time; 355 #endif /* !__HAVE_TIMECOUNTER */ 356 357 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 358 void *softclock_si; 359 #endif 360 361 #ifdef __HAVE_TIMECOUNTER 362 static u_int get_intr_timecount(struct timecounter *); 363 364 static struct timecounter intr_timecounter = { 365 get_intr_timecount, /* get_timecount */ 366 0, /* no poll_pps */ 367 ~0u, /* counter_mask */ 368 0, /* frequency */ 369 "clockinterrupt", /* name */ 370 0, /* quality - minimum implementation level for a clock */ 371 NULL, /* prev */ 372 NULL, /* next */ 373 }; 374 375 static u_int 376 get_intr_timecount(struct timecounter *tc) 377 { 378 379 return (u_int)hardclock_ticks; 380 } 381 #endif 382 383 /* 384 * Initialize clock frequencies and start both clocks running. 385 */ 386 void 387 initclocks(void) 388 { 389 int i; 390 391 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 392 softclock_si = softintr_establish(IPL_SOFTCLOCK, softclock, NULL); 393 if (softclock_si == NULL) 394 panic("initclocks: unable to register softclock intr"); 395 #endif 396 397 /* 398 * Set divisors to 1 (normal case) and let the machine-specific 399 * code do its bit. 400 */ 401 psdiv = 1; 402 #ifdef __HAVE_TIMECOUNTER 403 /* 404 * provide minimum default time counter 405 * will only run at interrupt resolution 406 */ 407 intr_timecounter.tc_frequency = hz; 408 tc_init(&intr_timecounter); 409 #endif 410 cpu_initclocks(); 411 412 /* 413 * Compute profhz/stathz/rrticks, and fix profhz if needed. 414 */ 415 i = stathz ? stathz : hz; 416 if (profhz == 0) 417 profhz = i; 418 psratio = profhz / i; 419 rrticks = hz / 10; 420 if (schedhz == 0) { 421 /* 16Hz is best */ 422 statscheddiv = i / 16; 423 if (statscheddiv <= 0) 424 panic("statscheddiv"); 425 } 426 427 #ifndef __HAVE_TIMECOUNTER 428 #ifdef NTP 429 switch (hz) { 430 case 1: 431 shifthz = SHIFT_SCALE - 0; 432 break; 433 case 2: 434 shifthz = SHIFT_SCALE - 1; 435 break; 436 case 4: 437 shifthz = SHIFT_SCALE - 2; 438 break; 439 case 8: 440 shifthz = SHIFT_SCALE - 3; 441 break; 442 case 16: 443 shifthz = SHIFT_SCALE - 4; 444 break; 445 case 32: 446 shifthz = SHIFT_SCALE - 5; 447 break; 448 case 50: 449 case 60: 450 case 64: 451 shifthz = SHIFT_SCALE - 6; 452 break; 453 case 96: 454 case 100: 455 case 128: 456 shifthz = SHIFT_SCALE - 7; 457 break; 458 case 256: 459 shifthz = SHIFT_SCALE - 8; 460 break; 461 case 512: 462 shifthz = SHIFT_SCALE - 9; 463 break; 464 case 1000: 465 case 1024: 466 shifthz = SHIFT_SCALE - 10; 467 break; 468 case 1200: 469 case 2048: 470 shifthz = SHIFT_SCALE - 11; 471 break; 472 case 4096: 473 shifthz = SHIFT_SCALE - 12; 474 break; 475 case 8192: 476 shifthz = SHIFT_SCALE - 13; 477 break; 478 case 16384: 479 shifthz = SHIFT_SCALE - 14; 480 break; 481 case 32768: 482 shifthz = SHIFT_SCALE - 15; 483 break; 484 case 65536: 485 shifthz = SHIFT_SCALE - 16; 486 break; 487 default: 488 panic("weird hz"); 489 } 490 if (fixtick == 0) { 491 /* 492 * Give MD code a chance to set this to a better 493 * value; but, if it doesn't, we should. 494 */ 495 fixtick = (1000000 - (hz*tick)); 496 } 497 #endif /* NTP */ 498 #endif /* !__HAVE_TIMECOUNTER */ 499 } 500 501 /* 502 * The real-time timer, interrupting hz times per second. 503 */ 504 void 505 hardclock(struct clockframe *frame) 506 { 507 struct lwp *l; 508 struct proc *p; 509 struct cpu_info *ci = curcpu(); 510 struct ptimer *pt; 511 #ifndef __HAVE_TIMECOUNTER 512 int delta; 513 extern int tickdelta; 514 extern long timedelta; 515 #ifdef NTP 516 int time_update; 517 int ltemp; 518 #endif /* NTP */ 519 #endif /* __HAVE_TIMECOUNTER */ 520 521 l = curlwp; 522 if (l) { 523 p = l->l_proc; 524 /* 525 * Run current process's virtual and profile time, as needed. 526 */ 527 if (CLKF_USERMODE(frame) && p->p_timers && 528 (pt = LIST_FIRST(&p->p_timers->pts_virtual)) != NULL) 529 if (itimerdecr(pt, tick) == 0) 530 itimerfire(pt); 531 if (p->p_timers && 532 (pt = LIST_FIRST(&p->p_timers->pts_prof)) != NULL) 533 if (itimerdecr(pt, tick) == 0) 534 itimerfire(pt); 535 } 536 537 /* 538 * If no separate statistics clock is available, run it from here. 539 */ 540 if (stathz == 0) 541 statclock(frame); 542 if ((--ci->ci_schedstate.spc_rrticks) <= 0) 543 roundrobin(ci); 544 545 #if defined(MULTIPROCESSOR) 546 /* 547 * If we are not the primary CPU, we're not allowed to do 548 * any more work. 549 */ 550 if (CPU_IS_PRIMARY(ci) == 0) 551 return; 552 #endif 553 554 hardclock_ticks++; 555 556 #ifdef __HAVE_TIMECOUNTER 557 tc_ticktock(); 558 #else /* __HAVE_TIMECOUNTER */ 559 /* 560 * Increment the time-of-day. The increment is normally just 561 * ``tick''. If the machine is one which has a clock frequency 562 * such that ``hz'' would not divide the second evenly into 563 * milliseconds, a periodic adjustment must be applied. Finally, 564 * if we are still adjusting the time (see adjtime()), 565 * ``tickdelta'' may also be added in. 566 */ 567 delta = tick; 568 569 #ifndef NTP 570 if (tickfix) { 571 tickfixcnt += tickfix; 572 if (tickfixcnt >= tickfixinterval) { 573 delta++; 574 tickfixcnt -= tickfixinterval; 575 } 576 } 577 #endif /* !NTP */ 578 /* Imprecise 4bsd adjtime() handling */ 579 if (timedelta != 0) { 580 delta += tickdelta; 581 timedelta -= tickdelta; 582 } 583 584 #ifdef notyet 585 microset(); 586 #endif 587 588 #ifndef NTP 589 BUMPTIME(&time, delta); /* XXX Now done using NTP code below */ 590 #endif 591 BUMPTIME(&mono_time, delta); 592 593 #ifdef NTP 594 time_update = delta; 595 596 /* 597 * Compute the phase adjustment. If the low-order bits 598 * (time_phase) of the update overflow, bump the high-order bits 599 * (time_update). 600 */ 601 time_phase += time_adj; 602 if (time_phase <= -FINEUSEC) { 603 ltemp = -time_phase >> SHIFT_SCALE; 604 time_phase += ltemp << SHIFT_SCALE; 605 time_update -= ltemp; 606 } else if (time_phase >= FINEUSEC) { 607 ltemp = time_phase >> SHIFT_SCALE; 608 time_phase -= ltemp << SHIFT_SCALE; 609 time_update += ltemp; 610 } 611 612 #ifdef HIGHBALL 613 /* 614 * If the HIGHBALL board is installed, we need to adjust the 615 * external clock offset in order to close the hardware feedback 616 * loop. This will adjust the external clock phase and frequency 617 * in small amounts. The additional phase noise and frequency 618 * wander this causes should be minimal. We also need to 619 * discipline the kernel time variable, since the PLL is used to 620 * discipline the external clock. If the Highball board is not 621 * present, we discipline kernel time with the PLL as usual. We 622 * assume that the external clock phase adjustment (time_update) 623 * and kernel phase adjustment (clock_cpu) are less than the 624 * value of tick. 625 */ 626 clock_offset.tv_usec += time_update; 627 if (clock_offset.tv_usec >= 1000000) { 628 clock_offset.tv_sec++; 629 clock_offset.tv_usec -= 1000000; 630 } 631 if (clock_offset.tv_usec < 0) { 632 clock_offset.tv_sec--; 633 clock_offset.tv_usec += 1000000; 634 } 635 time.tv_usec += clock_cpu; 636 clock_cpu = 0; 637 #else 638 time.tv_usec += time_update; 639 #endif /* HIGHBALL */ 640 641 /* 642 * On rollover of the second the phase adjustment to be used for 643 * the next second is calculated. Also, the maximum error is 644 * increased by the tolerance. If the PPS frequency discipline 645 * code is present, the phase is increased to compensate for the 646 * CPU clock oscillator frequency error. 647 * 648 * On a 32-bit machine and given parameters in the timex.h 649 * header file, the maximum phase adjustment is +-512 ms and 650 * maximum frequency offset is a tad less than) +-512 ppm. On a 651 * 64-bit machine, you shouldn't need to ask. 652 */ 653 if (time.tv_usec >= 1000000) { 654 time.tv_usec -= 1000000; 655 time.tv_sec++; 656 time_maxerror += time_tolerance >> SHIFT_USEC; 657 658 /* 659 * Leap second processing. If in leap-insert state at 660 * the end of the day, the system clock is set back one 661 * second; if in leap-delete state, the system clock is 662 * set ahead one second. The microtime() routine or 663 * external clock driver will insure that reported time 664 * is always monotonic. The ugly divides should be 665 * replaced. 666 */ 667 switch (time_state) { 668 case TIME_OK: 669 if (time_status & STA_INS) 670 time_state = TIME_INS; 671 else if (time_status & STA_DEL) 672 time_state = TIME_DEL; 673 break; 674 675 case TIME_INS: 676 if (time.tv_sec % 86400 == 0) { 677 time.tv_sec--; 678 time_state = TIME_OOP; 679 } 680 break; 681 682 case TIME_DEL: 683 if ((time.tv_sec + 1) % 86400 == 0) { 684 time.tv_sec++; 685 time_state = TIME_WAIT; 686 } 687 break; 688 689 case TIME_OOP: 690 time_state = TIME_WAIT; 691 break; 692 693 case TIME_WAIT: 694 if (!(time_status & (STA_INS | STA_DEL))) 695 time_state = TIME_OK; 696 break; 697 } 698 699 /* 700 * Compute the phase adjustment for the next second. In 701 * PLL mode, the offset is reduced by a fixed factor 702 * times the time constant. In FLL mode the offset is 703 * used directly. In either mode, the maximum phase 704 * adjustment for each second is clamped so as to spread 705 * the adjustment over not more than the number of 706 * seconds between updates. 707 */ 708 if (time_offset < 0) { 709 ltemp = -time_offset; 710 if (!(time_status & STA_FLL)) 711 ltemp >>= SHIFT_KG + time_constant; 712 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 713 ltemp = (MAXPHASE / MINSEC) << 714 SHIFT_UPDATE; 715 time_offset += ltemp; 716 time_adj = -ltemp << (shifthz - SHIFT_UPDATE); 717 } else if (time_offset > 0) { 718 ltemp = time_offset; 719 if (!(time_status & STA_FLL)) 720 ltemp >>= SHIFT_KG + time_constant; 721 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 722 ltemp = (MAXPHASE / MINSEC) << 723 SHIFT_UPDATE; 724 time_offset -= ltemp; 725 time_adj = ltemp << (shifthz - SHIFT_UPDATE); 726 } else 727 time_adj = 0; 728 729 /* 730 * Compute the frequency estimate and additional phase 731 * adjustment due to frequency error for the next 732 * second. When the PPS signal is engaged, gnaw on the 733 * watchdog counter and update the frequency computed by 734 * the pll and the PPS signal. 735 */ 736 #ifdef PPS_SYNC 737 pps_valid++; 738 if (pps_valid == PPS_VALID) { 739 pps_jitter = MAXTIME; 740 pps_stabil = MAXFREQ; 741 time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | 742 STA_PPSWANDER | STA_PPSERROR); 743 } 744 ltemp = time_freq + pps_freq; 745 #else 746 ltemp = time_freq; 747 #endif /* PPS_SYNC */ 748 749 if (ltemp < 0) 750 time_adj -= -ltemp >> (SHIFT_USEC - shifthz); 751 else 752 time_adj += ltemp >> (SHIFT_USEC - shifthz); 753 time_adj += (long)fixtick << shifthz; 754 755 /* 756 * When the CPU clock oscillator frequency is not a 757 * power of 2 in Hz, shifthz is only an approximate 758 * scale factor. 759 * 760 * To determine the adjustment, you can do the following: 761 * bc -q 762 * scale=24 763 * obase=2 764 * idealhz/realhz 765 * where `idealhz' is the next higher power of 2, and `realhz' 766 * is the actual value. You may need to factor this result 767 * into a sequence of 2 multipliers to get better precision. 768 * 769 * Likewise, the error can be calculated with (e.g. for 100Hz): 770 * bc -q 771 * scale=24 772 * ((1+2^-2+2^-5)*(1-2^-10)*realhz-idealhz)/idealhz 773 * (and then multiply by 1000000 to get ppm). 774 */ 775 switch (hz) { 776 case 60: 777 /* A factor of 1.000100010001 gives about 15ppm 778 error. */ 779 if (time_adj < 0) { 780 time_adj -= (-time_adj >> 4); 781 time_adj -= (-time_adj >> 8); 782 } else { 783 time_adj += (time_adj >> 4); 784 time_adj += (time_adj >> 8); 785 } 786 break; 787 788 case 96: 789 /* A factor of 1.0101010101 gives about 244ppm error. */ 790 if (time_adj < 0) { 791 time_adj -= (-time_adj >> 2); 792 time_adj -= (-time_adj >> 4) + (-time_adj >> 8); 793 } else { 794 time_adj += (time_adj >> 2); 795 time_adj += (time_adj >> 4) + (time_adj >> 8); 796 } 797 break; 798 799 case 50: 800 case 100: 801 /* A factor of 1.010001111010111 gives about 1ppm 802 error. */ 803 if (time_adj < 0) { 804 time_adj -= (-time_adj >> 2) + (-time_adj >> 5); 805 time_adj += (-time_adj >> 10); 806 } else { 807 time_adj += (time_adj >> 2) + (time_adj >> 5); 808 time_adj -= (time_adj >> 10); 809 } 810 break; 811 812 case 1000: 813 /* A factor of 1.000001100010100001 gives about 50ppm 814 error. */ 815 if (time_adj < 0) { 816 time_adj -= (-time_adj >> 6) + (-time_adj >> 11); 817 time_adj -= (-time_adj >> 7); 818 } else { 819 time_adj += (time_adj >> 6) + (time_adj >> 11); 820 time_adj += (time_adj >> 7); 821 } 822 break; 823 824 case 1200: 825 /* A factor of 1.1011010011100001 gives about 64ppm 826 error. */ 827 if (time_adj < 0) { 828 time_adj -= (-time_adj >> 1) + (-time_adj >> 6); 829 time_adj -= (-time_adj >> 3) + (-time_adj >> 10); 830 } else { 831 time_adj += (time_adj >> 1) + (time_adj >> 6); 832 time_adj += (time_adj >> 3) + (time_adj >> 10); 833 } 834 break; 835 } 836 837 #ifdef EXT_CLOCK 838 /* 839 * If an external clock is present, it is necessary to 840 * discipline the kernel time variable anyway, since not 841 * all system components use the microtime() interface. 842 * Here, the time offset between the external clock and 843 * kernel time variable is computed every so often. 844 */ 845 clock_count++; 846 if (clock_count > CLOCK_INTERVAL) { 847 clock_count = 0; 848 microtime(&clock_ext); 849 delta.tv_sec = clock_ext.tv_sec - time.tv_sec; 850 delta.tv_usec = clock_ext.tv_usec - 851 time.tv_usec; 852 if (delta.tv_usec < 0) 853 delta.tv_sec--; 854 if (delta.tv_usec >= 500000) { 855 delta.tv_usec -= 1000000; 856 delta.tv_sec++; 857 } 858 if (delta.tv_usec < -500000) { 859 delta.tv_usec += 1000000; 860 delta.tv_sec--; 861 } 862 if (delta.tv_sec > 0 || (delta.tv_sec == 0 && 863 delta.tv_usec > MAXPHASE) || 864 delta.tv_sec < -1 || (delta.tv_sec == -1 && 865 delta.tv_usec < -MAXPHASE)) { 866 time = clock_ext; 867 delta.tv_sec = 0; 868 delta.tv_usec = 0; 869 } 870 #ifdef HIGHBALL 871 clock_cpu = delta.tv_usec; 872 #else /* HIGHBALL */ 873 hardupdate(delta.tv_usec); 874 #endif /* HIGHBALL */ 875 } 876 #endif /* EXT_CLOCK */ 877 } 878 879 #endif /* NTP */ 880 #endif /* !__HAVE_TIMECOUNTER */ 881 882 /* 883 * Update real-time timeout queue. 884 * Process callouts at a very low CPU priority, so we don't keep the 885 * relatively high clock interrupt priority any longer than necessary. 886 */ 887 if (callout_hardclock()) { 888 if (CLKF_BASEPRI(frame)) { 889 /* 890 * Save the overhead of a software interrupt; 891 * it will happen as soon as we return, so do 892 * it now. 893 */ 894 spllowersoftclock(); 895 KERNEL_LOCK(LK_CANRECURSE|LK_EXCLUSIVE); 896 softclock(NULL); 897 KERNEL_UNLOCK(); 898 } else { 899 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 900 softintr_schedule(softclock_si); 901 #else 902 setsoftclock(); 903 #endif 904 } 905 } 906 } 907 908 #ifdef __HAVE_TIMECOUNTER 909 /* 910 * Compute number of hz until specified time. Used to compute second 911 * argument to callout_reset() from an absolute time. 912 */ 913 int 914 hzto(struct timeval *tvp) 915 { 916 struct timeval now, tv; 917 918 tv = *tvp; /* Don't modify original tvp. */ 919 getmicrotime(&now); 920 timersub(&tv, &now, &tv); 921 return tvtohz(&tv); 922 } 923 #endif /* __HAVE_TIMECOUNTER */ 924 925 /* 926 * Compute number of ticks in the specified amount of time. 927 */ 928 int 929 tvtohz(struct timeval *tv) 930 { 931 unsigned long ticks; 932 long sec, usec; 933 934 /* 935 * If the number of usecs in the whole seconds part of the time 936 * difference fits in a long, then the total number of usecs will 937 * fit in an unsigned long. Compute the total and convert it to 938 * ticks, rounding up and adding 1 to allow for the current tick 939 * to expire. Rounding also depends on unsigned long arithmetic 940 * to avoid overflow. 941 * 942 * Otherwise, if the number of ticks in the whole seconds part of 943 * the time difference fits in a long, then convert the parts to 944 * ticks separately and add, using similar rounding methods and 945 * overflow avoidance. This method would work in the previous 946 * case, but it is slightly slower and assumes that hz is integral. 947 * 948 * Otherwise, round the time difference down to the maximum 949 * representable value. 950 * 951 * If ints are 32-bit, then the maximum value for any timeout in 952 * 10ms ticks is 248 days. 953 */ 954 sec = tv->tv_sec; 955 usec = tv->tv_usec; 956 957 if (usec < 0) { 958 sec--; 959 usec += 1000000; 960 } 961 962 if (sec < 0 || (sec == 0 && usec <= 0)) { 963 /* 964 * Would expire now or in the past. Return 0 ticks. 965 * This is different from the legacy hzto() interface, 966 * and callers need to check for it. 967 */ 968 ticks = 0; 969 } else if (sec <= (LONG_MAX / 1000000)) 970 ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1)) 971 / tick) + 1; 972 else if (sec <= (LONG_MAX / hz)) 973 ticks = (sec * hz) + 974 (((unsigned long)usec + (tick - 1)) / tick) + 1; 975 else 976 ticks = LONG_MAX; 977 978 if (ticks > INT_MAX) 979 ticks = INT_MAX; 980 981 return ((int)ticks); 982 } 983 984 #ifndef __HAVE_TIMECOUNTER 985 /* 986 * Compute number of hz until specified time. Used to compute second 987 * argument to callout_reset() from an absolute time. 988 */ 989 int 990 hzto(struct timeval *tv) 991 { 992 unsigned long ticks; 993 long sec, usec; 994 int s; 995 996 /* 997 * If the number of usecs in the whole seconds part of the time 998 * difference fits in a long, then the total number of usecs will 999 * fit in an unsigned long. Compute the total and convert it to 1000 * ticks, rounding up and adding 1 to allow for the current tick 1001 * to expire. Rounding also depends on unsigned long arithmetic 1002 * to avoid overflow. 1003 * 1004 * Otherwise, if the number of ticks in the whole seconds part of 1005 * the time difference fits in a long, then convert the parts to 1006 * ticks separately and add, using similar rounding methods and 1007 * overflow avoidance. This method would work in the previous 1008 * case, but it is slightly slower and assume that hz is integral. 1009 * 1010 * Otherwise, round the time difference down to the maximum 1011 * representable value. 1012 * 1013 * If ints are 32-bit, then the maximum value for any timeout in 1014 * 10ms ticks is 248 days. 1015 */ 1016 s = splclock(); 1017 sec = tv->tv_sec - time.tv_sec; 1018 usec = tv->tv_usec - time.tv_usec; 1019 splx(s); 1020 1021 if (usec < 0) { 1022 sec--; 1023 usec += 1000000; 1024 } 1025 1026 if (sec < 0 || (sec == 0 && usec <= 0)) { 1027 /* 1028 * Would expire now or in the past. Return 0 ticks. 1029 * This is different from the legacy hzto() interface, 1030 * and callers need to check for it. 1031 */ 1032 ticks = 0; 1033 } else if (sec <= (LONG_MAX / 1000000)) 1034 ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1)) 1035 / tick) + 1; 1036 else if (sec <= (LONG_MAX / hz)) 1037 ticks = (sec * hz) + 1038 (((unsigned long)usec + (tick - 1)) / tick) + 1; 1039 else 1040 ticks = LONG_MAX; 1041 1042 if (ticks > INT_MAX) 1043 ticks = INT_MAX; 1044 1045 return ((int)ticks); 1046 } 1047 #endif /* !__HAVE_TIMECOUNTER */ 1048 1049 /* 1050 * Compute number of ticks in the specified amount of time. 1051 */ 1052 int 1053 tstohz(struct timespec *ts) 1054 { 1055 struct timeval tv; 1056 1057 /* 1058 * usec has great enough resolution for hz, so convert to a 1059 * timeval and use tvtohz() above. 1060 */ 1061 TIMESPEC_TO_TIMEVAL(&tv, ts); 1062 return tvtohz(&tv); 1063 } 1064 1065 /* 1066 * Start profiling on a process. 1067 * 1068 * Kernel profiling passes proc0 which never exits and hence 1069 * keeps the profile clock running constantly. 1070 */ 1071 void 1072 startprofclock(struct proc *p) 1073 { 1074 1075 if ((p->p_flag & P_PROFIL) == 0) { 1076 p->p_flag |= P_PROFIL; 1077 /* 1078 * This is only necessary if using the clock as the 1079 * profiling source. 1080 */ 1081 if (++profprocs == 1 && stathz != 0) 1082 psdiv = psratio; 1083 } 1084 } 1085 1086 /* 1087 * Stop profiling on a process. 1088 */ 1089 void 1090 stopprofclock(struct proc *p) 1091 { 1092 1093 if (p->p_flag & P_PROFIL) { 1094 p->p_flag &= ~P_PROFIL; 1095 /* 1096 * This is only necessary if using the clock as the 1097 * profiling source. 1098 */ 1099 if (--profprocs == 0 && stathz != 0) 1100 psdiv = 1; 1101 } 1102 } 1103 1104 #if defined(PERFCTRS) 1105 /* 1106 * Independent profiling "tick" in case we're using a separate 1107 * clock or profiling event source. Currently, that's just 1108 * performance counters--hence the wrapper. 1109 */ 1110 void 1111 proftick(struct clockframe *frame) 1112 { 1113 #ifdef GPROF 1114 struct gmonparam *g; 1115 intptr_t i; 1116 #endif 1117 struct proc *p; 1118 1119 p = curproc; 1120 if (CLKF_USERMODE(frame)) { 1121 if (p->p_flag & P_PROFIL) 1122 addupc_intr(p, CLKF_PC(frame)); 1123 } else { 1124 #ifdef GPROF 1125 g = &_gmonparam; 1126 if (g->state == GMON_PROF_ON) { 1127 i = CLKF_PC(frame) - g->lowpc; 1128 if (i < g->textsize) { 1129 i /= HISTFRACTION * sizeof(*g->kcount); 1130 g->kcount[i]++; 1131 } 1132 } 1133 #endif 1134 #ifdef PROC_PC 1135 if (p && (p->p_flag & P_PROFIL)) 1136 addupc_intr(p, PROC_PC(p)); 1137 #endif 1138 } 1139 } 1140 #endif 1141 1142 /* 1143 * Statistics clock. Grab profile sample, and if divider reaches 0, 1144 * do process and kernel statistics. 1145 */ 1146 void 1147 statclock(struct clockframe *frame) 1148 { 1149 #ifdef GPROF 1150 struct gmonparam *g; 1151 intptr_t i; 1152 #endif 1153 struct cpu_info *ci = curcpu(); 1154 struct schedstate_percpu *spc = &ci->ci_schedstate; 1155 struct proc *p; 1156 struct lwp *l; 1157 1158 /* 1159 * Notice changes in divisor frequency, and adjust clock 1160 * frequency accordingly. 1161 */ 1162 if (spc->spc_psdiv != psdiv) { 1163 spc->spc_psdiv = psdiv; 1164 spc->spc_pscnt = psdiv; 1165 if (psdiv == 1) { 1166 setstatclockrate(stathz); 1167 } else { 1168 setstatclockrate(profhz); 1169 } 1170 } 1171 l = curlwp; 1172 p = (l ? l->l_proc : NULL); 1173 if (CLKF_USERMODE(frame)) { 1174 KASSERT(p != NULL); 1175 1176 if ((p->p_flag & P_PROFIL) && profsrc == PROFSRC_CLOCK) 1177 addupc_intr(p, CLKF_PC(frame)); 1178 if (--spc->spc_pscnt > 0) 1179 return; 1180 /* 1181 * Came from user mode; CPU was in user state. 1182 * If this process is being profiled record the tick. 1183 */ 1184 p->p_uticks++; 1185 if (p->p_nice > NZERO) 1186 spc->spc_cp_time[CP_NICE]++; 1187 else 1188 spc->spc_cp_time[CP_USER]++; 1189 } else { 1190 #ifdef GPROF 1191 /* 1192 * Kernel statistics are just like addupc_intr, only easier. 1193 */ 1194 g = &_gmonparam; 1195 if (profsrc == PROFSRC_CLOCK && g->state == GMON_PROF_ON) { 1196 i = CLKF_PC(frame) - g->lowpc; 1197 if (i < g->textsize) { 1198 i /= HISTFRACTION * sizeof(*g->kcount); 1199 g->kcount[i]++; 1200 } 1201 } 1202 #endif 1203 #ifdef LWP_PC 1204 if (p && profsrc == PROFSRC_CLOCK && (p->p_flag & P_PROFIL)) 1205 addupc_intr(p, LWP_PC(l)); 1206 #endif 1207 if (--spc->spc_pscnt > 0) 1208 return; 1209 /* 1210 * Came from kernel mode, so we were: 1211 * - handling an interrupt, 1212 * - doing syscall or trap work on behalf of the current 1213 * user process, or 1214 * - spinning in the idle loop. 1215 * Whichever it is, charge the time as appropriate. 1216 * Note that we charge interrupts to the current process, 1217 * regardless of whether they are ``for'' that process, 1218 * so that we know how much of its real time was spent 1219 * in ``non-process'' (i.e., interrupt) work. 1220 */ 1221 if (CLKF_INTR(frame)) { 1222 if (p != NULL) 1223 p->p_iticks++; 1224 spc->spc_cp_time[CP_INTR]++; 1225 } else if (p != NULL) { 1226 p->p_sticks++; 1227 spc->spc_cp_time[CP_SYS]++; 1228 } else 1229 spc->spc_cp_time[CP_IDLE]++; 1230 } 1231 spc->spc_pscnt = psdiv; 1232 1233 if (p != NULL) { 1234 ++p->p_cpticks; 1235 /* 1236 * If no separate schedclock is provided, call it here 1237 * at about 16 Hz. 1238 */ 1239 if (schedhz == 0) 1240 if ((int)(--ci->ci_schedstate.spc_schedticks) <= 0) { 1241 schedclock(l); 1242 ci->ci_schedstate.spc_schedticks = statscheddiv; 1243 } 1244 } 1245 } 1246 1247 #ifndef __HAVE_TIMECOUNTER 1248 #ifdef NTP /* NTP phase-locked loop in kernel */ 1249 /* 1250 * hardupdate() - local clock update 1251 * 1252 * This routine is called by ntp_adjtime() to update the local clock 1253 * phase and frequency. The implementation is of an adaptive-parameter, 1254 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 1255 * time and frequency offset estimates for each call. If the kernel PPS 1256 * discipline code is configured (PPS_SYNC), the PPS signal itself 1257 * determines the new time offset, instead of the calling argument. 1258 * Presumably, calls to ntp_adjtime() occur only when the caller 1259 * believes the local clock is valid within some bound (+-128 ms with 1260 * NTP). If the caller's time is far different than the PPS time, an 1261 * argument will ensue, and it's not clear who will lose. 1262 * 1263 * For uncompensated quartz crystal oscillatores and nominal update 1264 * intervals less than 1024 s, operation should be in phase-lock mode 1265 * (STA_FLL = 0), where the loop is disciplined to phase. For update 1266 * intervals greater than thiss, operation should be in frequency-lock 1267 * mode (STA_FLL = 1), where the loop is disciplined to frequency. 1268 * 1269 * Note: splclock() is in effect. 1270 */ 1271 void 1272 hardupdate(long offset) 1273 { 1274 long ltemp, mtemp; 1275 1276 if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME)) 1277 return; 1278 ltemp = offset; 1279 #ifdef PPS_SYNC 1280 if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL) 1281 ltemp = pps_offset; 1282 #endif /* PPS_SYNC */ 1283 1284 /* 1285 * Scale the phase adjustment and clamp to the operating range. 1286 */ 1287 if (ltemp > MAXPHASE) 1288 time_offset = MAXPHASE << SHIFT_UPDATE; 1289 else if (ltemp < -MAXPHASE) 1290 time_offset = -(MAXPHASE << SHIFT_UPDATE); 1291 else 1292 time_offset = ltemp << SHIFT_UPDATE; 1293 1294 /* 1295 * Select whether the frequency is to be controlled and in which 1296 * mode (PLL or FLL). Clamp to the operating range. Ugly 1297 * multiply/divide should be replaced someday. 1298 */ 1299 if (time_status & STA_FREQHOLD || time_reftime == 0) 1300 time_reftime = time.tv_sec; 1301 mtemp = time.tv_sec - time_reftime; 1302 time_reftime = time.tv_sec; 1303 if (time_status & STA_FLL) { 1304 if (mtemp >= MINSEC) { 1305 ltemp = ((time_offset / mtemp) << (SHIFT_USEC - 1306 SHIFT_UPDATE)); 1307 if (ltemp < 0) 1308 time_freq -= -ltemp >> SHIFT_KH; 1309 else 1310 time_freq += ltemp >> SHIFT_KH; 1311 } 1312 } else { 1313 if (mtemp < MAXSEC) { 1314 ltemp *= mtemp; 1315 if (ltemp < 0) 1316 time_freq -= -ltemp >> (time_constant + 1317 time_constant + SHIFT_KF - 1318 SHIFT_USEC); 1319 else 1320 time_freq += ltemp >> (time_constant + 1321 time_constant + SHIFT_KF - 1322 SHIFT_USEC); 1323 } 1324 } 1325 if (time_freq > time_tolerance) 1326 time_freq = time_tolerance; 1327 else if (time_freq < -time_tolerance) 1328 time_freq = -time_tolerance; 1329 } 1330 1331 #ifdef PPS_SYNC 1332 /* 1333 * hardpps() - discipline CPU clock oscillator to external PPS signal 1334 * 1335 * This routine is called at each PPS interrupt in order to discipline 1336 * the CPU clock oscillator to the PPS signal. It measures the PPS phase 1337 * and leaves it in a handy spot for the hardclock() routine. It 1338 * integrates successive PPS phase differences and calculates the 1339 * frequency offset. This is used in hardclock() to discipline the CPU 1340 * clock oscillator so that intrinsic frequency error is cancelled out. 1341 * The code requires the caller to capture the time and hardware counter 1342 * value at the on-time PPS signal transition. 1343 * 1344 * Note that, on some Unix systems, this routine runs at an interrupt 1345 * priority level higher than the timer interrupt routine hardclock(). 1346 * Therefore, the variables used are distinct from the hardclock() 1347 * variables, except for certain exceptions: The PPS frequency pps_freq 1348 * and phase pps_offset variables are determined by this routine and 1349 * updated atomically. The time_tolerance variable can be considered a 1350 * constant, since it is infrequently changed, and then only when the 1351 * PPS signal is disabled. The watchdog counter pps_valid is updated 1352 * once per second by hardclock() and is atomically cleared in this 1353 * routine. 1354 */ 1355 void 1356 hardpps(struct timeval *tvp, /* time at PPS */ 1357 long usec /* hardware counter at PPS */) 1358 { 1359 long u_usec, v_usec, bigtick; 1360 long cal_sec, cal_usec; 1361 1362 /* 1363 * An occasional glitch can be produced when the PPS interrupt 1364 * occurs in the hardclock() routine before the time variable is 1365 * updated. Here the offset is discarded when the difference 1366 * between it and the last one is greater than tick/2, but not 1367 * if the interval since the first discard exceeds 30 s. 1368 */ 1369 time_status |= STA_PPSSIGNAL; 1370 time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); 1371 pps_valid = 0; 1372 u_usec = -tvp->tv_usec; 1373 if (u_usec < -500000) 1374 u_usec += 1000000; 1375 v_usec = pps_offset - u_usec; 1376 if (v_usec < 0) 1377 v_usec = -v_usec; 1378 if (v_usec > (tick >> 1)) { 1379 if (pps_glitch > MAXGLITCH) { 1380 pps_glitch = 0; 1381 pps_tf[2] = u_usec; 1382 pps_tf[1] = u_usec; 1383 } else { 1384 pps_glitch++; 1385 u_usec = pps_offset; 1386 } 1387 } else 1388 pps_glitch = 0; 1389 1390 /* 1391 * A three-stage median filter is used to help deglitch the pps 1392 * time. The median sample becomes the time offset estimate; the 1393 * difference between the other two samples becomes the time 1394 * dispersion (jitter) estimate. 1395 */ 1396 pps_tf[2] = pps_tf[1]; 1397 pps_tf[1] = pps_tf[0]; 1398 pps_tf[0] = u_usec; 1399 if (pps_tf[0] > pps_tf[1]) { 1400 if (pps_tf[1] > pps_tf[2]) { 1401 pps_offset = pps_tf[1]; /* 0 1 2 */ 1402 v_usec = pps_tf[0] - pps_tf[2]; 1403 } else if (pps_tf[2] > pps_tf[0]) { 1404 pps_offset = pps_tf[0]; /* 2 0 1 */ 1405 v_usec = pps_tf[2] - pps_tf[1]; 1406 } else { 1407 pps_offset = pps_tf[2]; /* 0 2 1 */ 1408 v_usec = pps_tf[0] - pps_tf[1]; 1409 } 1410 } else { 1411 if (pps_tf[1] < pps_tf[2]) { 1412 pps_offset = pps_tf[1]; /* 2 1 0 */ 1413 v_usec = pps_tf[2] - pps_tf[0]; 1414 } else if (pps_tf[2] < pps_tf[0]) { 1415 pps_offset = pps_tf[0]; /* 1 0 2 */ 1416 v_usec = pps_tf[1] - pps_tf[2]; 1417 } else { 1418 pps_offset = pps_tf[2]; /* 1 2 0 */ 1419 v_usec = pps_tf[1] - pps_tf[0]; 1420 } 1421 } 1422 if (v_usec > MAXTIME) 1423 pps_jitcnt++; 1424 v_usec = (v_usec << PPS_AVG) - pps_jitter; 1425 if (v_usec < 0) 1426 pps_jitter -= -v_usec >> PPS_AVG; 1427 else 1428 pps_jitter += v_usec >> PPS_AVG; 1429 if (pps_jitter > (MAXTIME >> 1)) 1430 time_status |= STA_PPSJITTER; 1431 1432 /* 1433 * During the calibration interval adjust the starting time when 1434 * the tick overflows. At the end of the interval compute the 1435 * duration of the interval and the difference of the hardware 1436 * counters at the beginning and end of the interval. This code 1437 * is deliciously complicated by the fact valid differences may 1438 * exceed the value of tick when using long calibration 1439 * intervals and small ticks. Note that the counter can be 1440 * greater than tick if caught at just the wrong instant, but 1441 * the values returned and used here are correct. 1442 */ 1443 bigtick = (long)tick << SHIFT_USEC; 1444 pps_usec -= pps_freq; 1445 if (pps_usec >= bigtick) 1446 pps_usec -= bigtick; 1447 if (pps_usec < 0) 1448 pps_usec += bigtick; 1449 pps_time.tv_sec++; 1450 pps_count++; 1451 if (pps_count < (1 << pps_shift)) 1452 return; 1453 pps_count = 0; 1454 pps_calcnt++; 1455 u_usec = usec << SHIFT_USEC; 1456 v_usec = pps_usec - u_usec; 1457 if (v_usec >= bigtick >> 1) 1458 v_usec -= bigtick; 1459 if (v_usec < -(bigtick >> 1)) 1460 v_usec += bigtick; 1461 if (v_usec < 0) 1462 v_usec = -(-v_usec >> pps_shift); 1463 else 1464 v_usec = v_usec >> pps_shift; 1465 pps_usec = u_usec; 1466 cal_sec = tvp->tv_sec; 1467 cal_usec = tvp->tv_usec; 1468 cal_sec -= pps_time.tv_sec; 1469 cal_usec -= pps_time.tv_usec; 1470 if (cal_usec < 0) { 1471 cal_usec += 1000000; 1472 cal_sec--; 1473 } 1474 pps_time = *tvp; 1475 1476 /* 1477 * Check for lost interrupts, noise, excessive jitter and 1478 * excessive frequency error. The number of timer ticks during 1479 * the interval may vary +-1 tick. Add to this a margin of one 1480 * tick for the PPS signal jitter and maximum frequency 1481 * deviation. If the limits are exceeded, the calibration 1482 * interval is reset to the minimum and we start over. 1483 */ 1484 u_usec = (long)tick << 1; 1485 if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec)) 1486 || (cal_sec == 0 && cal_usec < u_usec)) 1487 || v_usec > time_tolerance || v_usec < -time_tolerance) { 1488 pps_errcnt++; 1489 pps_shift = PPS_SHIFT; 1490 pps_intcnt = 0; 1491 time_status |= STA_PPSERROR; 1492 return; 1493 } 1494 1495 /* 1496 * A three-stage median filter is used to help deglitch the pps 1497 * frequency. The median sample becomes the frequency offset 1498 * estimate; the difference between the other two samples 1499 * becomes the frequency dispersion (stability) estimate. 1500 */ 1501 pps_ff[2] = pps_ff[1]; 1502 pps_ff[1] = pps_ff[0]; 1503 pps_ff[0] = v_usec; 1504 if (pps_ff[0] > pps_ff[1]) { 1505 if (pps_ff[1] > pps_ff[2]) { 1506 u_usec = pps_ff[1]; /* 0 1 2 */ 1507 v_usec = pps_ff[0] - pps_ff[2]; 1508 } else if (pps_ff[2] > pps_ff[0]) { 1509 u_usec = pps_ff[0]; /* 2 0 1 */ 1510 v_usec = pps_ff[2] - pps_ff[1]; 1511 } else { 1512 u_usec = pps_ff[2]; /* 0 2 1 */ 1513 v_usec = pps_ff[0] - pps_ff[1]; 1514 } 1515 } else { 1516 if (pps_ff[1] < pps_ff[2]) { 1517 u_usec = pps_ff[1]; /* 2 1 0 */ 1518 v_usec = pps_ff[2] - pps_ff[0]; 1519 } else if (pps_ff[2] < pps_ff[0]) { 1520 u_usec = pps_ff[0]; /* 1 0 2 */ 1521 v_usec = pps_ff[1] - pps_ff[2]; 1522 } else { 1523 u_usec = pps_ff[2]; /* 1 2 0 */ 1524 v_usec = pps_ff[1] - pps_ff[0]; 1525 } 1526 } 1527 1528 /* 1529 * Here the frequency dispersion (stability) is updated. If it 1530 * is less than one-fourth the maximum (MAXFREQ), the frequency 1531 * offset is updated as well, but clamped to the tolerance. It 1532 * will be processed later by the hardclock() routine. 1533 */ 1534 v_usec = (v_usec >> 1) - pps_stabil; 1535 if (v_usec < 0) 1536 pps_stabil -= -v_usec >> PPS_AVG; 1537 else 1538 pps_stabil += v_usec >> PPS_AVG; 1539 if (pps_stabil > MAXFREQ >> 2) { 1540 pps_stbcnt++; 1541 time_status |= STA_PPSWANDER; 1542 return; 1543 } 1544 if (time_status & STA_PPSFREQ) { 1545 if (u_usec < 0) { 1546 pps_freq -= -u_usec >> PPS_AVG; 1547 if (pps_freq < -time_tolerance) 1548 pps_freq = -time_tolerance; 1549 u_usec = -u_usec; 1550 } else { 1551 pps_freq += u_usec >> PPS_AVG; 1552 if (pps_freq > time_tolerance) 1553 pps_freq = time_tolerance; 1554 } 1555 } 1556 1557 /* 1558 * Here the calibration interval is adjusted. If the maximum 1559 * time difference is greater than tick / 4, reduce the interval 1560 * by half. If this is not the case for four consecutive 1561 * intervals, double the interval. 1562 */ 1563 if (u_usec << pps_shift > bigtick >> 2) { 1564 pps_intcnt = 0; 1565 if (pps_shift > PPS_SHIFT) 1566 pps_shift--; 1567 } else if (pps_intcnt >= 4) { 1568 pps_intcnt = 0; 1569 if (pps_shift < PPS_SHIFTMAX) 1570 pps_shift++; 1571 } else 1572 pps_intcnt++; 1573 } 1574 #endif /* PPS_SYNC */ 1575 #endif /* NTP */ 1576 1577 /* timecounter compat functions */ 1578 void 1579 nanotime(struct timespec *ts) 1580 { 1581 struct timeval tv; 1582 1583 microtime(&tv); 1584 TIMEVAL_TO_TIMESPEC(&tv, ts); 1585 } 1586 1587 void 1588 getbinuptime(struct bintime *bt) 1589 { 1590 struct timeval tv; 1591 1592 microtime(&tv); 1593 timeval2bintime(&tv, bt); 1594 } 1595 1596 void 1597 nanouptime(struct timespec *tsp) 1598 { 1599 int s; 1600 1601 s = splclock(); 1602 TIMEVAL_TO_TIMESPEC(&mono_time, tsp); 1603 splx(s); 1604 } 1605 1606 void 1607 getnanouptime(struct timespec *tsp) 1608 { 1609 int s; 1610 1611 s = splclock(); 1612 TIMEVAL_TO_TIMESPEC(&mono_time, tsp); 1613 splx(s); 1614 } 1615 1616 void 1617 getmicrouptime(struct timeval *tvp) 1618 { 1619 int s; 1620 1621 s = splclock(); 1622 *tvp = mono_time; 1623 splx(s); 1624 } 1625 1626 void 1627 getnanotime(struct timespec *tsp) 1628 { 1629 int s; 1630 1631 s = splclock(); 1632 TIMEVAL_TO_TIMESPEC(&time, tsp); 1633 splx(s); 1634 } 1635 1636 void 1637 getmicrotime(struct timeval *tvp) 1638 { 1639 int s; 1640 1641 s = splclock(); 1642 *tvp = time; 1643 splx(s); 1644 } 1645 #endif /* !__HAVE_TIMECOUNTER */ 1646