1 /* $NetBSD: kern_clock.c,v 1.101 2006/06/09 22:47:56 kardel 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 1.101 2006/06/09 22:47:56 kardel 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 }; 372 373 static u_int 374 get_intr_timecount(struct timecounter *tc) 375 { 376 return (u_int)hardclock_ticks; 377 } 378 #endif 379 380 /* 381 * Initialize clock frequencies and start both clocks running. 382 */ 383 void 384 initclocks(void) 385 { 386 int i; 387 388 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 389 softclock_si = softintr_establish(IPL_SOFTCLOCK, softclock, NULL); 390 if (softclock_si == NULL) 391 panic("initclocks: unable to register softclock intr"); 392 #endif 393 394 /* 395 * Set divisors to 1 (normal case) and let the machine-specific 396 * code do its bit. 397 */ 398 psdiv = 1; 399 #ifdef __HAVE_TIMECOUNTER 400 /* 401 * provide minimum default time counter 402 * will only run at interrupt resolution 403 */ 404 intr_timecounter.tc_frequency = hz; 405 tc_init(&intr_timecounter); 406 #endif 407 cpu_initclocks(); 408 409 /* 410 * Compute profhz/stathz/rrticks, and fix profhz if needed. 411 */ 412 i = stathz ? stathz : hz; 413 if (profhz == 0) 414 profhz = i; 415 psratio = profhz / i; 416 rrticks = hz / 10; 417 if (schedhz == 0) { 418 /* 16Hz is best */ 419 statscheddiv = i / 16; 420 if (statscheddiv <= 0) 421 panic("statscheddiv"); 422 } 423 424 #ifndef __HAVE_TIMECOUNTER 425 #ifdef NTP 426 switch (hz) { 427 case 1: 428 shifthz = SHIFT_SCALE - 0; 429 break; 430 case 2: 431 shifthz = SHIFT_SCALE - 1; 432 break; 433 case 4: 434 shifthz = SHIFT_SCALE - 2; 435 break; 436 case 8: 437 shifthz = SHIFT_SCALE - 3; 438 break; 439 case 16: 440 shifthz = SHIFT_SCALE - 4; 441 break; 442 case 32: 443 shifthz = SHIFT_SCALE - 5; 444 break; 445 case 50: 446 case 60: 447 case 64: 448 shifthz = SHIFT_SCALE - 6; 449 break; 450 case 96: 451 case 100: 452 case 128: 453 shifthz = SHIFT_SCALE - 7; 454 break; 455 case 256: 456 shifthz = SHIFT_SCALE - 8; 457 break; 458 case 512: 459 shifthz = SHIFT_SCALE - 9; 460 break; 461 case 1000: 462 case 1024: 463 shifthz = SHIFT_SCALE - 10; 464 break; 465 case 1200: 466 case 2048: 467 shifthz = SHIFT_SCALE - 11; 468 break; 469 case 4096: 470 shifthz = SHIFT_SCALE - 12; 471 break; 472 case 8192: 473 shifthz = SHIFT_SCALE - 13; 474 break; 475 case 16384: 476 shifthz = SHIFT_SCALE - 14; 477 break; 478 case 32768: 479 shifthz = SHIFT_SCALE - 15; 480 break; 481 case 65536: 482 shifthz = SHIFT_SCALE - 16; 483 break; 484 default: 485 panic("weird hz"); 486 } 487 if (fixtick == 0) { 488 /* 489 * Give MD code a chance to set this to a better 490 * value; but, if it doesn't, we should. 491 */ 492 fixtick = (1000000 - (hz*tick)); 493 } 494 #endif /* NTP */ 495 #endif /* !__HAVE_TIMECOUNTER */ 496 } 497 498 /* 499 * The real-time timer, interrupting hz times per second. 500 */ 501 void 502 hardclock(struct clockframe *frame) 503 { 504 struct lwp *l; 505 struct proc *p; 506 struct cpu_info *ci = curcpu(); 507 struct ptimer *pt; 508 #ifndef __HAVE_TIMECOUNTER 509 int delta; 510 extern int tickdelta; 511 extern long timedelta; 512 #ifdef NTP 513 int time_update; 514 int ltemp; 515 #endif /* NTP */ 516 #endif /* __HAVE_TIMECOUNTER */ 517 518 l = curlwp; 519 if (l) { 520 p = l->l_proc; 521 /* 522 * Run current process's virtual and profile time, as needed. 523 */ 524 if (CLKF_USERMODE(frame) && p->p_timers && 525 (pt = LIST_FIRST(&p->p_timers->pts_virtual)) != NULL) 526 if (itimerdecr(pt, tick) == 0) 527 itimerfire(pt); 528 if (p->p_timers && 529 (pt = LIST_FIRST(&p->p_timers->pts_prof)) != NULL) 530 if (itimerdecr(pt, tick) == 0) 531 itimerfire(pt); 532 } 533 534 /* 535 * If no separate statistics clock is available, run it from here. 536 */ 537 if (stathz == 0) 538 statclock(frame); 539 if ((--ci->ci_schedstate.spc_rrticks) <= 0) 540 roundrobin(ci); 541 542 #if defined(MULTIPROCESSOR) 543 /* 544 * If we are not the primary CPU, we're not allowed to do 545 * any more work. 546 */ 547 if (CPU_IS_PRIMARY(ci) == 0) 548 return; 549 #endif 550 551 hardclock_ticks++; 552 553 #ifdef __HAVE_TIMECOUNTER 554 tc_ticktock(); 555 #else /* __HAVE_TIMECOUNTER */ 556 /* 557 * Increment the time-of-day. The increment is normally just 558 * ``tick''. If the machine is one which has a clock frequency 559 * such that ``hz'' would not divide the second evenly into 560 * milliseconds, a periodic adjustment must be applied. Finally, 561 * if we are still adjusting the time (see adjtime()), 562 * ``tickdelta'' may also be added in. 563 */ 564 delta = tick; 565 566 #ifndef NTP 567 if (tickfix) { 568 tickfixcnt += tickfix; 569 if (tickfixcnt >= tickfixinterval) { 570 delta++; 571 tickfixcnt -= tickfixinterval; 572 } 573 } 574 #endif /* !NTP */ 575 /* Imprecise 4bsd adjtime() handling */ 576 if (timedelta != 0) { 577 delta += tickdelta; 578 timedelta -= tickdelta; 579 } 580 581 #ifdef notyet 582 microset(); 583 #endif 584 585 #ifndef NTP 586 BUMPTIME(&time, delta); /* XXX Now done using NTP code below */ 587 #endif 588 BUMPTIME(&mono_time, delta); 589 590 #ifdef NTP 591 time_update = delta; 592 593 /* 594 * Compute the phase adjustment. If the low-order bits 595 * (time_phase) of the update overflow, bump the high-order bits 596 * (time_update). 597 */ 598 time_phase += time_adj; 599 if (time_phase <= -FINEUSEC) { 600 ltemp = -time_phase >> SHIFT_SCALE; 601 time_phase += ltemp << SHIFT_SCALE; 602 time_update -= ltemp; 603 } else if (time_phase >= FINEUSEC) { 604 ltemp = time_phase >> SHIFT_SCALE; 605 time_phase -= ltemp << SHIFT_SCALE; 606 time_update += ltemp; 607 } 608 609 #ifdef HIGHBALL 610 /* 611 * If the HIGHBALL board is installed, we need to adjust the 612 * external clock offset in order to close the hardware feedback 613 * loop. This will adjust the external clock phase and frequency 614 * in small amounts. The additional phase noise and frequency 615 * wander this causes should be minimal. We also need to 616 * discipline the kernel time variable, since the PLL is used to 617 * discipline the external clock. If the Highball board is not 618 * present, we discipline kernel time with the PLL as usual. We 619 * assume that the external clock phase adjustment (time_update) 620 * and kernel phase adjustment (clock_cpu) are less than the 621 * value of tick. 622 */ 623 clock_offset.tv_usec += time_update; 624 if (clock_offset.tv_usec >= 1000000) { 625 clock_offset.tv_sec++; 626 clock_offset.tv_usec -= 1000000; 627 } 628 if (clock_offset.tv_usec < 0) { 629 clock_offset.tv_sec--; 630 clock_offset.tv_usec += 1000000; 631 } 632 time.tv_usec += clock_cpu; 633 clock_cpu = 0; 634 #else 635 time.tv_usec += time_update; 636 #endif /* HIGHBALL */ 637 638 /* 639 * On rollover of the second the phase adjustment to be used for 640 * the next second is calculated. Also, the maximum error is 641 * increased by the tolerance. If the PPS frequency discipline 642 * code is present, the phase is increased to compensate for the 643 * CPU clock oscillator frequency error. 644 * 645 * On a 32-bit machine and given parameters in the timex.h 646 * header file, the maximum phase adjustment is +-512 ms and 647 * maximum frequency offset is a tad less than) +-512 ppm. On a 648 * 64-bit machine, you shouldn't need to ask. 649 */ 650 if (time.tv_usec >= 1000000) { 651 time.tv_usec -= 1000000; 652 time.tv_sec++; 653 time_maxerror += time_tolerance >> SHIFT_USEC; 654 655 /* 656 * Leap second processing. If in leap-insert state at 657 * the end of the day, the system clock is set back one 658 * second; if in leap-delete state, the system clock is 659 * set ahead one second. The microtime() routine or 660 * external clock driver will insure that reported time 661 * is always monotonic. The ugly divides should be 662 * replaced. 663 */ 664 switch (time_state) { 665 case TIME_OK: 666 if (time_status & STA_INS) 667 time_state = TIME_INS; 668 else if (time_status & STA_DEL) 669 time_state = TIME_DEL; 670 break; 671 672 case TIME_INS: 673 if (time.tv_sec % 86400 == 0) { 674 time.tv_sec--; 675 time_state = TIME_OOP; 676 } 677 break; 678 679 case TIME_DEL: 680 if ((time.tv_sec + 1) % 86400 == 0) { 681 time.tv_sec++; 682 time_state = TIME_WAIT; 683 } 684 break; 685 686 case TIME_OOP: 687 time_state = TIME_WAIT; 688 break; 689 690 case TIME_WAIT: 691 if (!(time_status & (STA_INS | STA_DEL))) 692 time_state = TIME_OK; 693 break; 694 } 695 696 /* 697 * Compute the phase adjustment for the next second. In 698 * PLL mode, the offset is reduced by a fixed factor 699 * times the time constant. In FLL mode the offset is 700 * used directly. In either mode, the maximum phase 701 * adjustment for each second is clamped so as to spread 702 * the adjustment over not more than the number of 703 * seconds between updates. 704 */ 705 if (time_offset < 0) { 706 ltemp = -time_offset; 707 if (!(time_status & STA_FLL)) 708 ltemp >>= SHIFT_KG + time_constant; 709 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 710 ltemp = (MAXPHASE / MINSEC) << 711 SHIFT_UPDATE; 712 time_offset += ltemp; 713 time_adj = -ltemp << (shifthz - SHIFT_UPDATE); 714 } else if (time_offset > 0) { 715 ltemp = time_offset; 716 if (!(time_status & STA_FLL)) 717 ltemp >>= SHIFT_KG + time_constant; 718 if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) 719 ltemp = (MAXPHASE / MINSEC) << 720 SHIFT_UPDATE; 721 time_offset -= ltemp; 722 time_adj = ltemp << (shifthz - SHIFT_UPDATE); 723 } else 724 time_adj = 0; 725 726 /* 727 * Compute the frequency estimate and additional phase 728 * adjustment due to frequency error for the next 729 * second. When the PPS signal is engaged, gnaw on the 730 * watchdog counter and update the frequency computed by 731 * the pll and the PPS signal. 732 */ 733 #ifdef PPS_SYNC 734 pps_valid++; 735 if (pps_valid == PPS_VALID) { 736 pps_jitter = MAXTIME; 737 pps_stabil = MAXFREQ; 738 time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | 739 STA_PPSWANDER | STA_PPSERROR); 740 } 741 ltemp = time_freq + pps_freq; 742 #else 743 ltemp = time_freq; 744 #endif /* PPS_SYNC */ 745 746 if (ltemp < 0) 747 time_adj -= -ltemp >> (SHIFT_USEC - shifthz); 748 else 749 time_adj += ltemp >> (SHIFT_USEC - shifthz); 750 time_adj += (long)fixtick << shifthz; 751 752 /* 753 * When the CPU clock oscillator frequency is not a 754 * power of 2 in Hz, shifthz is only an approximate 755 * scale factor. 756 * 757 * To determine the adjustment, you can do the following: 758 * bc -q 759 * scale=24 760 * obase=2 761 * idealhz/realhz 762 * where `idealhz' is the next higher power of 2, and `realhz' 763 * is the actual value. You may need to factor this result 764 * into a sequence of 2 multipliers to get better precision. 765 * 766 * Likewise, the error can be calculated with (e.g. for 100Hz): 767 * bc -q 768 * scale=24 769 * ((1+2^-2+2^-5)*(1-2^-10)*realhz-idealhz)/idealhz 770 * (and then multiply by 1000000 to get ppm). 771 */ 772 switch (hz) { 773 case 60: 774 /* A factor of 1.000100010001 gives about 15ppm 775 error. */ 776 if (time_adj < 0) { 777 time_adj -= (-time_adj >> 4); 778 time_adj -= (-time_adj >> 8); 779 } else { 780 time_adj += (time_adj >> 4); 781 time_adj += (time_adj >> 8); 782 } 783 break; 784 785 case 96: 786 /* A factor of 1.0101010101 gives about 244ppm error. */ 787 if (time_adj < 0) { 788 time_adj -= (-time_adj >> 2); 789 time_adj -= (-time_adj >> 4) + (-time_adj >> 8); 790 } else { 791 time_adj += (time_adj >> 2); 792 time_adj += (time_adj >> 4) + (time_adj >> 8); 793 } 794 break; 795 796 case 50: 797 case 100: 798 /* A factor of 1.010001111010111 gives about 1ppm 799 error. */ 800 if (time_adj < 0) { 801 time_adj -= (-time_adj >> 2) + (-time_adj >> 5); 802 time_adj += (-time_adj >> 10); 803 } else { 804 time_adj += (time_adj >> 2) + (time_adj >> 5); 805 time_adj -= (time_adj >> 10); 806 } 807 break; 808 809 case 1000: 810 /* A factor of 1.000001100010100001 gives about 50ppm 811 error. */ 812 if (time_adj < 0) { 813 time_adj -= (-time_adj >> 6) + (-time_adj >> 11); 814 time_adj -= (-time_adj >> 7); 815 } else { 816 time_adj += (time_adj >> 6) + (time_adj >> 11); 817 time_adj += (time_adj >> 7); 818 } 819 break; 820 821 case 1200: 822 /* A factor of 1.1011010011100001 gives about 64ppm 823 error. */ 824 if (time_adj < 0) { 825 time_adj -= (-time_adj >> 1) + (-time_adj >> 6); 826 time_adj -= (-time_adj >> 3) + (-time_adj >> 10); 827 } else { 828 time_adj += (time_adj >> 1) + (time_adj >> 6); 829 time_adj += (time_adj >> 3) + (time_adj >> 10); 830 } 831 break; 832 } 833 834 #ifdef EXT_CLOCK 835 /* 836 * If an external clock is present, it is necessary to 837 * discipline the kernel time variable anyway, since not 838 * all system components use the microtime() interface. 839 * Here, the time offset between the external clock and 840 * kernel time variable is computed every so often. 841 */ 842 clock_count++; 843 if (clock_count > CLOCK_INTERVAL) { 844 clock_count = 0; 845 microtime(&clock_ext); 846 delta.tv_sec = clock_ext.tv_sec - time.tv_sec; 847 delta.tv_usec = clock_ext.tv_usec - 848 time.tv_usec; 849 if (delta.tv_usec < 0) 850 delta.tv_sec--; 851 if (delta.tv_usec >= 500000) { 852 delta.tv_usec -= 1000000; 853 delta.tv_sec++; 854 } 855 if (delta.tv_usec < -500000) { 856 delta.tv_usec += 1000000; 857 delta.tv_sec--; 858 } 859 if (delta.tv_sec > 0 || (delta.tv_sec == 0 && 860 delta.tv_usec > MAXPHASE) || 861 delta.tv_sec < -1 || (delta.tv_sec == -1 && 862 delta.tv_usec < -MAXPHASE)) { 863 time = clock_ext; 864 delta.tv_sec = 0; 865 delta.tv_usec = 0; 866 } 867 #ifdef HIGHBALL 868 clock_cpu = delta.tv_usec; 869 #else /* HIGHBALL */ 870 hardupdate(delta.tv_usec); 871 #endif /* HIGHBALL */ 872 } 873 #endif /* EXT_CLOCK */ 874 } 875 876 #endif /* NTP */ 877 #endif /* !__HAVE_TIMECOUNTER */ 878 879 /* 880 * Update real-time timeout queue. 881 * Process callouts at a very low CPU priority, so we don't keep the 882 * relatively high clock interrupt priority any longer than necessary. 883 */ 884 if (callout_hardclock()) { 885 if (CLKF_BASEPRI(frame)) { 886 /* 887 * Save the overhead of a software interrupt; 888 * it will happen as soon as we return, so do 889 * it now. 890 */ 891 spllowersoftclock(); 892 KERNEL_LOCK(LK_CANRECURSE|LK_EXCLUSIVE); 893 softclock(NULL); 894 KERNEL_UNLOCK(); 895 } else { 896 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS 897 softintr_schedule(softclock_si); 898 #else 899 setsoftclock(); 900 #endif 901 } 902 } 903 } 904 905 #ifdef __HAVE_TIMECOUNTER 906 /* 907 * Compute number of hz until specified time. Used to compute second 908 * argument to callout_reset() from an absolute time. 909 */ 910 int 911 hzto(struct timeval *tvp) 912 { 913 struct timeval now, tv; 914 915 tv = *tvp; /* Don't modify original tvp. */ 916 getmicrotime(&now); 917 timersub(&tv, &now, &tv); 918 return tvtohz(&tv); 919 } 920 #endif /* __HAVE_TIMECOUNTER */ 921 922 /* 923 * Compute number of ticks in the specified amount of time. 924 */ 925 int 926 tvtohz(struct timeval *tv) 927 { 928 unsigned long ticks; 929 long sec, usec; 930 931 /* 932 * If the number of usecs in the whole seconds part of the time 933 * difference fits in a long, then the total number of usecs will 934 * fit in an unsigned long. Compute the total and convert it to 935 * ticks, rounding up and adding 1 to allow for the current tick 936 * to expire. Rounding also depends on unsigned long arithmetic 937 * to avoid overflow. 938 * 939 * Otherwise, if the number of ticks in the whole seconds part of 940 * the time difference fits in a long, then convert the parts to 941 * ticks separately and add, using similar rounding methods and 942 * overflow avoidance. This method would work in the previous 943 * case, but it is slightly slower and assumes that hz is integral. 944 * 945 * Otherwise, round the time difference down to the maximum 946 * representable value. 947 * 948 * If ints are 32-bit, then the maximum value for any timeout in 949 * 10ms ticks is 248 days. 950 */ 951 sec = tv->tv_sec; 952 usec = tv->tv_usec; 953 954 if (usec < 0) { 955 sec--; 956 usec += 1000000; 957 } 958 959 if (sec < 0 || (sec == 0 && usec <= 0)) { 960 /* 961 * Would expire now or in the past. Return 0 ticks. 962 * This is different from the legacy hzto() interface, 963 * and callers need to check for it. 964 */ 965 ticks = 0; 966 } else if (sec <= (LONG_MAX / 1000000)) 967 ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1)) 968 / tick) + 1; 969 else if (sec <= (LONG_MAX / hz)) 970 ticks = (sec * hz) + 971 (((unsigned long)usec + (tick - 1)) / tick) + 1; 972 else 973 ticks = LONG_MAX; 974 975 if (ticks > INT_MAX) 976 ticks = INT_MAX; 977 978 return ((int)ticks); 979 } 980 981 #ifndef __HAVE_TIMECOUNTER 982 /* 983 * Compute number of hz until specified time. Used to compute second 984 * argument to callout_reset() from an absolute time. 985 */ 986 int 987 hzto(struct timeval *tv) 988 { 989 unsigned long ticks; 990 long sec, usec; 991 int s; 992 993 /* 994 * If the number of usecs in the whole seconds part of the time 995 * difference fits in a long, then the total number of usecs will 996 * fit in an unsigned long. Compute the total and convert it to 997 * ticks, rounding up and adding 1 to allow for the current tick 998 * to expire. Rounding also depends on unsigned long arithmetic 999 * to avoid overflow. 1000 * 1001 * Otherwise, if the number of ticks in the whole seconds part of 1002 * the time difference fits in a long, then convert the parts to 1003 * ticks separately and add, using similar rounding methods and 1004 * overflow avoidance. This method would work in the previous 1005 * case, but it is slightly slower and assume that hz is integral. 1006 * 1007 * Otherwise, round the time difference down to the maximum 1008 * representable value. 1009 * 1010 * If ints are 32-bit, then the maximum value for any timeout in 1011 * 10ms ticks is 248 days. 1012 */ 1013 s = splclock(); 1014 sec = tv->tv_sec - time.tv_sec; 1015 usec = tv->tv_usec - time.tv_usec; 1016 splx(s); 1017 1018 if (usec < 0) { 1019 sec--; 1020 usec += 1000000; 1021 } 1022 1023 if (sec < 0 || (sec == 0 && usec <= 0)) { 1024 /* 1025 * Would expire now or in the past. Return 0 ticks. 1026 * This is different from the legacy hzto() interface, 1027 * and callers need to check for it. 1028 */ 1029 ticks = 0; 1030 } else if (sec <= (LONG_MAX / 1000000)) 1031 ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1)) 1032 / tick) + 1; 1033 else if (sec <= (LONG_MAX / hz)) 1034 ticks = (sec * hz) + 1035 (((unsigned long)usec + (tick - 1)) / tick) + 1; 1036 else 1037 ticks = LONG_MAX; 1038 1039 if (ticks > INT_MAX) 1040 ticks = INT_MAX; 1041 1042 return ((int)ticks); 1043 } 1044 #endif /* !__HAVE_TIMECOUNTER */ 1045 1046 /* 1047 * Compute number of ticks in the specified amount of time. 1048 */ 1049 int 1050 tstohz(struct timespec *ts) 1051 { 1052 struct timeval tv; 1053 1054 /* 1055 * usec has great enough resolution for hz, so convert to a 1056 * timeval and use tvtohz() above. 1057 */ 1058 TIMESPEC_TO_TIMEVAL(&tv, ts); 1059 return tvtohz(&tv); 1060 } 1061 1062 /* 1063 * Start profiling on a process. 1064 * 1065 * Kernel profiling passes proc0 which never exits and hence 1066 * keeps the profile clock running constantly. 1067 */ 1068 void 1069 startprofclock(struct proc *p) 1070 { 1071 1072 if ((p->p_flag & P_PROFIL) == 0) { 1073 p->p_flag |= P_PROFIL; 1074 /* 1075 * This is only necessary if using the clock as the 1076 * profiling source. 1077 */ 1078 if (++profprocs == 1 && stathz != 0) 1079 psdiv = psratio; 1080 } 1081 } 1082 1083 /* 1084 * Stop profiling on a process. 1085 */ 1086 void 1087 stopprofclock(struct proc *p) 1088 { 1089 1090 if (p->p_flag & P_PROFIL) { 1091 p->p_flag &= ~P_PROFIL; 1092 /* 1093 * This is only necessary if using the clock as the 1094 * profiling source. 1095 */ 1096 if (--profprocs == 0 && stathz != 0) 1097 psdiv = 1; 1098 } 1099 } 1100 1101 #if defined(PERFCTRS) 1102 /* 1103 * Independent profiling "tick" in case we're using a separate 1104 * clock or profiling event source. Currently, that's just 1105 * performance counters--hence the wrapper. 1106 */ 1107 void 1108 proftick(struct clockframe *frame) 1109 { 1110 #ifdef GPROF 1111 struct gmonparam *g; 1112 intptr_t i; 1113 #endif 1114 struct proc *p; 1115 1116 p = curproc; 1117 if (CLKF_USERMODE(frame)) { 1118 if (p->p_flag & P_PROFIL) 1119 addupc_intr(p, CLKF_PC(frame)); 1120 } else { 1121 #ifdef GPROF 1122 g = &_gmonparam; 1123 if (g->state == GMON_PROF_ON) { 1124 i = CLKF_PC(frame) - g->lowpc; 1125 if (i < g->textsize) { 1126 i /= HISTFRACTION * sizeof(*g->kcount); 1127 g->kcount[i]++; 1128 } 1129 } 1130 #endif 1131 #ifdef PROC_PC 1132 if (p && (p->p_flag & P_PROFIL)) 1133 addupc_intr(p, PROC_PC(p)); 1134 #endif 1135 } 1136 } 1137 #endif 1138 1139 /* 1140 * Statistics clock. Grab profile sample, and if divider reaches 0, 1141 * do process and kernel statistics. 1142 */ 1143 void 1144 statclock(struct clockframe *frame) 1145 { 1146 #ifdef GPROF 1147 struct gmonparam *g; 1148 intptr_t i; 1149 #endif 1150 struct cpu_info *ci = curcpu(); 1151 struct schedstate_percpu *spc = &ci->ci_schedstate; 1152 struct proc *p; 1153 struct lwp *l; 1154 1155 /* 1156 * Notice changes in divisor frequency, and adjust clock 1157 * frequency accordingly. 1158 */ 1159 if (spc->spc_psdiv != psdiv) { 1160 spc->spc_psdiv = psdiv; 1161 spc->spc_pscnt = psdiv; 1162 if (psdiv == 1) { 1163 setstatclockrate(stathz); 1164 } else { 1165 setstatclockrate(profhz); 1166 } 1167 } 1168 l = curlwp; 1169 p = (l ? l->l_proc : NULL); 1170 if (CLKF_USERMODE(frame)) { 1171 KASSERT(p != NULL); 1172 1173 if ((p->p_flag & P_PROFIL) && profsrc == PROFSRC_CLOCK) 1174 addupc_intr(p, CLKF_PC(frame)); 1175 if (--spc->spc_pscnt > 0) 1176 return; 1177 /* 1178 * Came from user mode; CPU was in user state. 1179 * If this process is being profiled record the tick. 1180 */ 1181 p->p_uticks++; 1182 if (p->p_nice > NZERO) 1183 spc->spc_cp_time[CP_NICE]++; 1184 else 1185 spc->spc_cp_time[CP_USER]++; 1186 } else { 1187 #ifdef GPROF 1188 /* 1189 * Kernel statistics are just like addupc_intr, only easier. 1190 */ 1191 g = &_gmonparam; 1192 if (profsrc == PROFSRC_CLOCK && g->state == GMON_PROF_ON) { 1193 i = CLKF_PC(frame) - g->lowpc; 1194 if (i < g->textsize) { 1195 i /= HISTFRACTION * sizeof(*g->kcount); 1196 g->kcount[i]++; 1197 } 1198 } 1199 #endif 1200 #ifdef LWP_PC 1201 if (p && profsrc == PROFSRC_CLOCK && (p->p_flag & P_PROFIL)) 1202 addupc_intr(p, LWP_PC(l)); 1203 #endif 1204 if (--spc->spc_pscnt > 0) 1205 return; 1206 /* 1207 * Came from kernel mode, so we were: 1208 * - handling an interrupt, 1209 * - doing syscall or trap work on behalf of the current 1210 * user process, or 1211 * - spinning in the idle loop. 1212 * Whichever it is, charge the time as appropriate. 1213 * Note that we charge interrupts to the current process, 1214 * regardless of whether they are ``for'' that process, 1215 * so that we know how much of its real time was spent 1216 * in ``non-process'' (i.e., interrupt) work. 1217 */ 1218 if (CLKF_INTR(frame)) { 1219 if (p != NULL) 1220 p->p_iticks++; 1221 spc->spc_cp_time[CP_INTR]++; 1222 } else if (p != NULL) { 1223 p->p_sticks++; 1224 spc->spc_cp_time[CP_SYS]++; 1225 } else 1226 spc->spc_cp_time[CP_IDLE]++; 1227 } 1228 spc->spc_pscnt = psdiv; 1229 1230 if (p != NULL) { 1231 ++p->p_cpticks; 1232 /* 1233 * If no separate schedclock is provided, call it here 1234 * at about 16 Hz. 1235 */ 1236 if (schedhz == 0) 1237 if ((int)(--ci->ci_schedstate.spc_schedticks) <= 0) { 1238 schedclock(l); 1239 ci->ci_schedstate.spc_schedticks = statscheddiv; 1240 } 1241 } 1242 } 1243 1244 #ifndef __HAVE_TIMECOUNTER 1245 #ifdef NTP /* NTP phase-locked loop in kernel */ 1246 /* 1247 * hardupdate() - local clock update 1248 * 1249 * This routine is called by ntp_adjtime() to update the local clock 1250 * phase and frequency. The implementation is of an adaptive-parameter, 1251 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 1252 * time and frequency offset estimates for each call. If the kernel PPS 1253 * discipline code is configured (PPS_SYNC), the PPS signal itself 1254 * determines the new time offset, instead of the calling argument. 1255 * Presumably, calls to ntp_adjtime() occur only when the caller 1256 * believes the local clock is valid within some bound (+-128 ms with 1257 * NTP). If the caller's time is far different than the PPS time, an 1258 * argument will ensue, and it's not clear who will lose. 1259 * 1260 * For uncompensated quartz crystal oscillatores and nominal update 1261 * intervals less than 1024 s, operation should be in phase-lock mode 1262 * (STA_FLL = 0), where the loop is disciplined to phase. For update 1263 * intervals greater than thiss, operation should be in frequency-lock 1264 * mode (STA_FLL = 1), where the loop is disciplined to frequency. 1265 * 1266 * Note: splclock() is in effect. 1267 */ 1268 void 1269 hardupdate(long offset) 1270 { 1271 long ltemp, mtemp; 1272 1273 if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME)) 1274 return; 1275 ltemp = offset; 1276 #ifdef PPS_SYNC 1277 if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL) 1278 ltemp = pps_offset; 1279 #endif /* PPS_SYNC */ 1280 1281 /* 1282 * Scale the phase adjustment and clamp to the operating range. 1283 */ 1284 if (ltemp > MAXPHASE) 1285 time_offset = MAXPHASE << SHIFT_UPDATE; 1286 else if (ltemp < -MAXPHASE) 1287 time_offset = -(MAXPHASE << SHIFT_UPDATE); 1288 else 1289 time_offset = ltemp << SHIFT_UPDATE; 1290 1291 /* 1292 * Select whether the frequency is to be controlled and in which 1293 * mode (PLL or FLL). Clamp to the operating range. Ugly 1294 * multiply/divide should be replaced someday. 1295 */ 1296 if (time_status & STA_FREQHOLD || time_reftime == 0) 1297 time_reftime = time.tv_sec; 1298 mtemp = time.tv_sec - time_reftime; 1299 time_reftime = time.tv_sec; 1300 if (time_status & STA_FLL) { 1301 if (mtemp >= MINSEC) { 1302 ltemp = ((time_offset / mtemp) << (SHIFT_USEC - 1303 SHIFT_UPDATE)); 1304 if (ltemp < 0) 1305 time_freq -= -ltemp >> SHIFT_KH; 1306 else 1307 time_freq += ltemp >> SHIFT_KH; 1308 } 1309 } else { 1310 if (mtemp < MAXSEC) { 1311 ltemp *= mtemp; 1312 if (ltemp < 0) 1313 time_freq -= -ltemp >> (time_constant + 1314 time_constant + SHIFT_KF - 1315 SHIFT_USEC); 1316 else 1317 time_freq += ltemp >> (time_constant + 1318 time_constant + SHIFT_KF - 1319 SHIFT_USEC); 1320 } 1321 } 1322 if (time_freq > time_tolerance) 1323 time_freq = time_tolerance; 1324 else if (time_freq < -time_tolerance) 1325 time_freq = -time_tolerance; 1326 } 1327 1328 #ifdef PPS_SYNC 1329 /* 1330 * hardpps() - discipline CPU clock oscillator to external PPS signal 1331 * 1332 * This routine is called at each PPS interrupt in order to discipline 1333 * the CPU clock oscillator to the PPS signal. It measures the PPS phase 1334 * and leaves it in a handy spot for the hardclock() routine. It 1335 * integrates successive PPS phase differences and calculates the 1336 * frequency offset. This is used in hardclock() to discipline the CPU 1337 * clock oscillator so that intrinsic frequency error is cancelled out. 1338 * The code requires the caller to capture the time and hardware counter 1339 * value at the on-time PPS signal transition. 1340 * 1341 * Note that, on some Unix systems, this routine runs at an interrupt 1342 * priority level higher than the timer interrupt routine hardclock(). 1343 * Therefore, the variables used are distinct from the hardclock() 1344 * variables, except for certain exceptions: The PPS frequency pps_freq 1345 * and phase pps_offset variables are determined by this routine and 1346 * updated atomically. The time_tolerance variable can be considered a 1347 * constant, since it is infrequently changed, and then only when the 1348 * PPS signal is disabled. The watchdog counter pps_valid is updated 1349 * once per second by hardclock() and is atomically cleared in this 1350 * routine. 1351 */ 1352 void 1353 hardpps(struct timeval *tvp, /* time at PPS */ 1354 long usec /* hardware counter at PPS */) 1355 { 1356 long u_usec, v_usec, bigtick; 1357 long cal_sec, cal_usec; 1358 1359 /* 1360 * An occasional glitch can be produced when the PPS interrupt 1361 * occurs in the hardclock() routine before the time variable is 1362 * updated. Here the offset is discarded when the difference 1363 * between it and the last one is greater than tick/2, but not 1364 * if the interval since the first discard exceeds 30 s. 1365 */ 1366 time_status |= STA_PPSSIGNAL; 1367 time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); 1368 pps_valid = 0; 1369 u_usec = -tvp->tv_usec; 1370 if (u_usec < -500000) 1371 u_usec += 1000000; 1372 v_usec = pps_offset - u_usec; 1373 if (v_usec < 0) 1374 v_usec = -v_usec; 1375 if (v_usec > (tick >> 1)) { 1376 if (pps_glitch > MAXGLITCH) { 1377 pps_glitch = 0; 1378 pps_tf[2] = u_usec; 1379 pps_tf[1] = u_usec; 1380 } else { 1381 pps_glitch++; 1382 u_usec = pps_offset; 1383 } 1384 } else 1385 pps_glitch = 0; 1386 1387 /* 1388 * A three-stage median filter is used to help deglitch the pps 1389 * time. The median sample becomes the time offset estimate; the 1390 * difference between the other two samples becomes the time 1391 * dispersion (jitter) estimate. 1392 */ 1393 pps_tf[2] = pps_tf[1]; 1394 pps_tf[1] = pps_tf[0]; 1395 pps_tf[0] = u_usec; 1396 if (pps_tf[0] > pps_tf[1]) { 1397 if (pps_tf[1] > pps_tf[2]) { 1398 pps_offset = pps_tf[1]; /* 0 1 2 */ 1399 v_usec = pps_tf[0] - pps_tf[2]; 1400 } else if (pps_tf[2] > pps_tf[0]) { 1401 pps_offset = pps_tf[0]; /* 2 0 1 */ 1402 v_usec = pps_tf[2] - pps_tf[1]; 1403 } else { 1404 pps_offset = pps_tf[2]; /* 0 2 1 */ 1405 v_usec = pps_tf[0] - pps_tf[1]; 1406 } 1407 } else { 1408 if (pps_tf[1] < pps_tf[2]) { 1409 pps_offset = pps_tf[1]; /* 2 1 0 */ 1410 v_usec = pps_tf[2] - pps_tf[0]; 1411 } else if (pps_tf[2] < pps_tf[0]) { 1412 pps_offset = pps_tf[0]; /* 1 0 2 */ 1413 v_usec = pps_tf[1] - pps_tf[2]; 1414 } else { 1415 pps_offset = pps_tf[2]; /* 1 2 0 */ 1416 v_usec = pps_tf[1] - pps_tf[0]; 1417 } 1418 } 1419 if (v_usec > MAXTIME) 1420 pps_jitcnt++; 1421 v_usec = (v_usec << PPS_AVG) - pps_jitter; 1422 if (v_usec < 0) 1423 pps_jitter -= -v_usec >> PPS_AVG; 1424 else 1425 pps_jitter += v_usec >> PPS_AVG; 1426 if (pps_jitter > (MAXTIME >> 1)) 1427 time_status |= STA_PPSJITTER; 1428 1429 /* 1430 * During the calibration interval adjust the starting time when 1431 * the tick overflows. At the end of the interval compute the 1432 * duration of the interval and the difference of the hardware 1433 * counters at the beginning and end of the interval. This code 1434 * is deliciously complicated by the fact valid differences may 1435 * exceed the value of tick when using long calibration 1436 * intervals and small ticks. Note that the counter can be 1437 * greater than tick if caught at just the wrong instant, but 1438 * the values returned and used here are correct. 1439 */ 1440 bigtick = (long)tick << SHIFT_USEC; 1441 pps_usec -= pps_freq; 1442 if (pps_usec >= bigtick) 1443 pps_usec -= bigtick; 1444 if (pps_usec < 0) 1445 pps_usec += bigtick; 1446 pps_time.tv_sec++; 1447 pps_count++; 1448 if (pps_count < (1 << pps_shift)) 1449 return; 1450 pps_count = 0; 1451 pps_calcnt++; 1452 u_usec = usec << SHIFT_USEC; 1453 v_usec = pps_usec - u_usec; 1454 if (v_usec >= bigtick >> 1) 1455 v_usec -= bigtick; 1456 if (v_usec < -(bigtick >> 1)) 1457 v_usec += bigtick; 1458 if (v_usec < 0) 1459 v_usec = -(-v_usec >> pps_shift); 1460 else 1461 v_usec = v_usec >> pps_shift; 1462 pps_usec = u_usec; 1463 cal_sec = tvp->tv_sec; 1464 cal_usec = tvp->tv_usec; 1465 cal_sec -= pps_time.tv_sec; 1466 cal_usec -= pps_time.tv_usec; 1467 if (cal_usec < 0) { 1468 cal_usec += 1000000; 1469 cal_sec--; 1470 } 1471 pps_time = *tvp; 1472 1473 /* 1474 * Check for lost interrupts, noise, excessive jitter and 1475 * excessive frequency error. The number of timer ticks during 1476 * the interval may vary +-1 tick. Add to this a margin of one 1477 * tick for the PPS signal jitter and maximum frequency 1478 * deviation. If the limits are exceeded, the calibration 1479 * interval is reset to the minimum and we start over. 1480 */ 1481 u_usec = (long)tick << 1; 1482 if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec)) 1483 || (cal_sec == 0 && cal_usec < u_usec)) 1484 || v_usec > time_tolerance || v_usec < -time_tolerance) { 1485 pps_errcnt++; 1486 pps_shift = PPS_SHIFT; 1487 pps_intcnt = 0; 1488 time_status |= STA_PPSERROR; 1489 return; 1490 } 1491 1492 /* 1493 * A three-stage median filter is used to help deglitch the pps 1494 * frequency. The median sample becomes the frequency offset 1495 * estimate; the difference between the other two samples 1496 * becomes the frequency dispersion (stability) estimate. 1497 */ 1498 pps_ff[2] = pps_ff[1]; 1499 pps_ff[1] = pps_ff[0]; 1500 pps_ff[0] = v_usec; 1501 if (pps_ff[0] > pps_ff[1]) { 1502 if (pps_ff[1] > pps_ff[2]) { 1503 u_usec = pps_ff[1]; /* 0 1 2 */ 1504 v_usec = pps_ff[0] - pps_ff[2]; 1505 } else if (pps_ff[2] > pps_ff[0]) { 1506 u_usec = pps_ff[0]; /* 2 0 1 */ 1507 v_usec = pps_ff[2] - pps_ff[1]; 1508 } else { 1509 u_usec = pps_ff[2]; /* 0 2 1 */ 1510 v_usec = pps_ff[0] - pps_ff[1]; 1511 } 1512 } else { 1513 if (pps_ff[1] < pps_ff[2]) { 1514 u_usec = pps_ff[1]; /* 2 1 0 */ 1515 v_usec = pps_ff[2] - pps_ff[0]; 1516 } else if (pps_ff[2] < pps_ff[0]) { 1517 u_usec = pps_ff[0]; /* 1 0 2 */ 1518 v_usec = pps_ff[1] - pps_ff[2]; 1519 } else { 1520 u_usec = pps_ff[2]; /* 1 2 0 */ 1521 v_usec = pps_ff[1] - pps_ff[0]; 1522 } 1523 } 1524 1525 /* 1526 * Here the frequency dispersion (stability) is updated. If it 1527 * is less than one-fourth the maximum (MAXFREQ), the frequency 1528 * offset is updated as well, but clamped to the tolerance. It 1529 * will be processed later by the hardclock() routine. 1530 */ 1531 v_usec = (v_usec >> 1) - pps_stabil; 1532 if (v_usec < 0) 1533 pps_stabil -= -v_usec >> PPS_AVG; 1534 else 1535 pps_stabil += v_usec >> PPS_AVG; 1536 if (pps_stabil > MAXFREQ >> 2) { 1537 pps_stbcnt++; 1538 time_status |= STA_PPSWANDER; 1539 return; 1540 } 1541 if (time_status & STA_PPSFREQ) { 1542 if (u_usec < 0) { 1543 pps_freq -= -u_usec >> PPS_AVG; 1544 if (pps_freq < -time_tolerance) 1545 pps_freq = -time_tolerance; 1546 u_usec = -u_usec; 1547 } else { 1548 pps_freq += u_usec >> PPS_AVG; 1549 if (pps_freq > time_tolerance) 1550 pps_freq = time_tolerance; 1551 } 1552 } 1553 1554 /* 1555 * Here the calibration interval is adjusted. If the maximum 1556 * time difference is greater than tick / 4, reduce the interval 1557 * by half. If this is not the case for four consecutive 1558 * intervals, double the interval. 1559 */ 1560 if (u_usec << pps_shift > bigtick >> 2) { 1561 pps_intcnt = 0; 1562 if (pps_shift > PPS_SHIFT) 1563 pps_shift--; 1564 } else if (pps_intcnt >= 4) { 1565 pps_intcnt = 0; 1566 if (pps_shift < PPS_SHIFTMAX) 1567 pps_shift++; 1568 } else 1569 pps_intcnt++; 1570 } 1571 #endif /* PPS_SYNC */ 1572 #endif /* NTP */ 1573 1574 /* timecounter compat functions */ 1575 void 1576 nanotime(struct timespec *ts) 1577 { 1578 struct timeval tv; 1579 1580 microtime(&tv); 1581 TIMEVAL_TO_TIMESPEC(&tv, ts); 1582 } 1583 1584 void 1585 getbinuptime(struct bintime *bt) 1586 { 1587 struct timeval tv; 1588 1589 microtime(&tv); 1590 timeval2bintime(&tv, bt); 1591 } 1592 1593 void 1594 nanouptime(struct timespec *tsp) 1595 { 1596 int s; 1597 1598 s = splclock(); 1599 TIMEVAL_TO_TIMESPEC(&mono_time, tsp); 1600 splx(s); 1601 } 1602 1603 void 1604 getnanouptime(struct timespec *tsp) 1605 { 1606 int s; 1607 1608 s = splclock(); 1609 TIMEVAL_TO_TIMESPEC(&mono_time, tsp); 1610 splx(s); 1611 } 1612 1613 void 1614 getmicrouptime(struct timeval *tvp) 1615 { 1616 int s; 1617 1618 s = splclock(); 1619 *tvp = mono_time; 1620 splx(s); 1621 } 1622 1623 void 1624 getnanotime(struct timespec *tsp) 1625 { 1626 int s; 1627 1628 s = splclock(); 1629 TIMEVAL_TO_TIMESPEC(&time, tsp); 1630 splx(s); 1631 } 1632 1633 void 1634 getmicrotime(struct timeval *tvp) 1635 { 1636 int s; 1637 1638 s = splclock(); 1639 *tvp = time; 1640 splx(s); 1641 } 1642 #endif /* !__HAVE_TIMECOUNTER */ 1643