1 /*- 2 * Copyright (c) 1982, 1986, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_device_polling.h" 41 #include "opt_hwpmc_hooks.h" 42 #include "opt_ntp.h" 43 #include "opt_watchdog.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/callout.h> 48 #include <sys/kdb.h> 49 #include <sys/kernel.h> 50 #include <sys/lock.h> 51 #include <sys/ktr.h> 52 #include <sys/mutex.h> 53 #include <sys/proc.h> 54 #include <sys/resource.h> 55 #include <sys/resourcevar.h> 56 #include <sys/sched.h> 57 #include <sys/signalvar.h> 58 #include <sys/smp.h> 59 #include <vm/vm.h> 60 #include <vm/pmap.h> 61 #include <vm/vm_map.h> 62 #include <sys/sysctl.h> 63 #include <sys/bus.h> 64 #include <sys/interrupt.h> 65 #include <sys/limits.h> 66 #include <sys/timetc.h> 67 68 #ifdef GPROF 69 #include <sys/gmon.h> 70 #endif 71 72 #ifdef HWPMC_HOOKS 73 #include <sys/pmckern.h> 74 #endif 75 76 #ifdef DEVICE_POLLING 77 extern void hardclock_device_poll(void); 78 #endif /* DEVICE_POLLING */ 79 80 static void initclocks(void *dummy); 81 SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL) 82 83 /* Some of these don't belong here, but it's easiest to concentrate them. */ 84 long cp_time[CPUSTATES]; 85 86 static int 87 sysctl_kern_cp_time(SYSCTL_HANDLER_ARGS) 88 { 89 int error; 90 #ifdef SCTL_MASK32 91 int i; 92 unsigned int cp_time32[CPUSTATES]; 93 94 if (req->flags & SCTL_MASK32) { 95 if (!req->oldptr) 96 return SYSCTL_OUT(req, 0, sizeof(cp_time32)); 97 for (i = 0; i < CPUSTATES; i++) 98 cp_time32[i] = (unsigned int)cp_time[i]; 99 error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32)); 100 } else 101 #endif 102 { 103 if (!req->oldptr) 104 return SYSCTL_OUT(req, 0, sizeof(cp_time)); 105 error = SYSCTL_OUT(req, cp_time, sizeof(cp_time)); 106 } 107 return error; 108 } 109 110 SYSCTL_PROC(_kern, OID_AUTO, cp_time, CTLTYPE_LONG|CTLFLAG_RD, 111 0,0, sysctl_kern_cp_time, "LU", "CPU time statistics"); 112 113 #ifdef SW_WATCHDOG 114 #include <sys/watchdog.h> 115 116 static int watchdog_ticks; 117 static int watchdog_enabled; 118 static void watchdog_fire(void); 119 static void watchdog_config(void *, u_int, int *); 120 #endif /* SW_WATCHDOG */ 121 122 /* 123 * Clock handling routines. 124 * 125 * This code is written to operate with two timers that run independently of 126 * each other. 127 * 128 * The main timer, running hz times per second, is used to trigger interval 129 * timers, timeouts and rescheduling as needed. 130 * 131 * The second timer handles kernel and user profiling, 132 * and does resource use estimation. If the second timer is programmable, 133 * it is randomized to avoid aliasing between the two clocks. For example, 134 * the randomization prevents an adversary from always giving up the cpu 135 * just before its quantum expires. Otherwise, it would never accumulate 136 * cpu ticks. The mean frequency of the second timer is stathz. 137 * 138 * If no second timer exists, stathz will be zero; in this case we drive 139 * profiling and statistics off the main clock. This WILL NOT be accurate; 140 * do not do it unless absolutely necessary. 141 * 142 * The statistics clock may (or may not) be run at a higher rate while 143 * profiling. This profile clock runs at profhz. We require that profhz 144 * be an integral multiple of stathz. 145 * 146 * If the statistics clock is running fast, it must be divided by the ratio 147 * profhz/stathz for statistics. (For profiling, every tick counts.) 148 * 149 * Time-of-day is maintained using a "timecounter", which may or may 150 * not be related to the hardware generating the above mentioned 151 * interrupts. 152 */ 153 154 int stathz; 155 int profhz; 156 int profprocs; 157 int ticks; 158 int psratio; 159 160 /* 161 * Initialize clock frequencies and start both clocks running. 162 */ 163 /* ARGSUSED*/ 164 static void 165 initclocks(dummy) 166 void *dummy; 167 { 168 register int i; 169 170 /* 171 * Set divisors to 1 (normal case) and let the machine-specific 172 * code do its bit. 173 */ 174 cpu_initclocks(); 175 176 /* 177 * Compute profhz/stathz, and fix profhz if needed. 178 */ 179 i = stathz ? stathz : hz; 180 if (profhz == 0) 181 profhz = i; 182 psratio = profhz / i; 183 #ifdef SW_WATCHDOG 184 EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0); 185 #endif 186 } 187 188 /* 189 * Each time the real-time timer fires, this function is called on all CPUs. 190 * Note that hardclock() calls hardclock_cpu() for the boot CPU, so only 191 * the other CPUs in the system need to call this function. 192 */ 193 void 194 hardclock_cpu(int usermode) 195 { 196 struct pstats *pstats; 197 struct thread *td = curthread; 198 struct proc *p = td->td_proc; 199 200 /* 201 * Run current process's virtual and profile time, as needed. 202 */ 203 mtx_lock_spin_flags(&sched_lock, MTX_QUIET); 204 if (p->p_flag & P_SA) { 205 /* XXXKSE What to do? */ 206 } else { 207 pstats = p->p_stats; 208 if (usermode && 209 timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) && 210 itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) { 211 p->p_sflag |= PS_ALRMPEND; 212 td->td_flags |= TDF_ASTPENDING; 213 } 214 if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value) && 215 itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) { 216 p->p_sflag |= PS_PROFPEND; 217 td->td_flags |= TDF_ASTPENDING; 218 } 219 } 220 mtx_unlock_spin_flags(&sched_lock, MTX_QUIET); 221 222 #ifdef HWPMC_HOOKS 223 if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid))) 224 PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL); 225 #endif 226 } 227 228 /* 229 * The real-time timer, interrupting hz times per second. 230 */ 231 void 232 hardclock(int usermode, uintfptr_t pc) 233 { 234 int need_softclock = 0; 235 236 hardclock_cpu(usermode); 237 238 tc_ticktock(); 239 /* 240 * If no separate statistics clock is available, run it from here. 241 * 242 * XXX: this only works for UP 243 */ 244 if (stathz == 0) { 245 profclock(usermode, pc); 246 statclock(usermode); 247 } 248 249 #ifdef DEVICE_POLLING 250 hardclock_device_poll(); /* this is very short and quick */ 251 #endif /* DEVICE_POLLING */ 252 253 /* 254 * Process callouts at a very low cpu priority, so we don't keep the 255 * relatively high clock interrupt priority any longer than necessary. 256 */ 257 mtx_lock_spin_flags(&callout_lock, MTX_QUIET); 258 ticks++; 259 if (TAILQ_FIRST(&callwheel[ticks & callwheelmask]) != NULL) { 260 need_softclock = 1; 261 } else if (softticks + 1 == ticks) 262 ++softticks; 263 mtx_unlock_spin_flags(&callout_lock, MTX_QUIET); 264 265 /* 266 * swi_sched acquires sched_lock, so we don't want to call it with 267 * callout_lock held; incorrect locking order. 268 */ 269 if (need_softclock) 270 swi_sched(softclock_ih, 0); 271 272 #ifdef SW_WATCHDOG 273 if (watchdog_enabled > 0 && --watchdog_ticks <= 0) 274 watchdog_fire(); 275 #endif /* SW_WATCHDOG */ 276 } 277 278 /* 279 * Compute number of ticks in the specified amount of time. 280 */ 281 int 282 tvtohz(tv) 283 struct timeval *tv; 284 { 285 register unsigned long ticks; 286 register long sec, usec; 287 288 /* 289 * If the number of usecs in the whole seconds part of the time 290 * difference fits in a long, then the total number of usecs will 291 * fit in an unsigned long. Compute the total and convert it to 292 * ticks, rounding up and adding 1 to allow for the current tick 293 * to expire. Rounding also depends on unsigned long arithmetic 294 * to avoid overflow. 295 * 296 * Otherwise, if the number of ticks in the whole seconds part of 297 * the time difference fits in a long, then convert the parts to 298 * ticks separately and add, using similar rounding methods and 299 * overflow avoidance. This method would work in the previous 300 * case but it is slightly slower and assumes that hz is integral. 301 * 302 * Otherwise, round the time difference down to the maximum 303 * representable value. 304 * 305 * If ints have 32 bits, then the maximum value for any timeout in 306 * 10ms ticks is 248 days. 307 */ 308 sec = tv->tv_sec; 309 usec = tv->tv_usec; 310 if (usec < 0) { 311 sec--; 312 usec += 1000000; 313 } 314 if (sec < 0) { 315 #ifdef DIAGNOSTIC 316 if (usec > 0) { 317 sec++; 318 usec -= 1000000; 319 } 320 printf("tvotohz: negative time difference %ld sec %ld usec\n", 321 sec, usec); 322 #endif 323 ticks = 1; 324 } else if (sec <= LONG_MAX / 1000000) 325 ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1)) 326 / tick + 1; 327 else if (sec <= LONG_MAX / hz) 328 ticks = sec * hz 329 + ((unsigned long)usec + (tick - 1)) / tick + 1; 330 else 331 ticks = LONG_MAX; 332 if (ticks > INT_MAX) 333 ticks = INT_MAX; 334 return ((int)ticks); 335 } 336 337 /* 338 * Start profiling on a process. 339 * 340 * Kernel profiling passes proc0 which never exits and hence 341 * keeps the profile clock running constantly. 342 */ 343 void 344 startprofclock(p) 345 register struct proc *p; 346 { 347 348 /* 349 * XXX; Right now sched_lock protects statclock(), but perhaps 350 * it should be protected later on by a time_lock, which would 351 * cover psdiv, etc. as well. 352 */ 353 PROC_LOCK_ASSERT(p, MA_OWNED); 354 if (p->p_flag & P_STOPPROF) 355 return; 356 if ((p->p_flag & P_PROFIL) == 0) { 357 mtx_lock_spin(&sched_lock); 358 p->p_flag |= P_PROFIL; 359 if (++profprocs == 1) 360 cpu_startprofclock(); 361 mtx_unlock_spin(&sched_lock); 362 } 363 } 364 365 /* 366 * Stop profiling on a process. 367 */ 368 void 369 stopprofclock(p) 370 register struct proc *p; 371 { 372 373 PROC_LOCK_ASSERT(p, MA_OWNED); 374 if (p->p_flag & P_PROFIL) { 375 if (p->p_profthreads != 0) { 376 p->p_flag |= P_STOPPROF; 377 while (p->p_profthreads != 0) 378 msleep(&p->p_profthreads, &p->p_mtx, PPAUSE, 379 "stopprof", 0); 380 p->p_flag &= ~P_STOPPROF; 381 } 382 if ((p->p_flag & P_PROFIL) == 0) 383 return; 384 mtx_lock_spin(&sched_lock); 385 p->p_flag &= ~P_PROFIL; 386 if (--profprocs == 0) 387 cpu_stopprofclock(); 388 mtx_unlock_spin(&sched_lock); 389 } 390 } 391 392 /* 393 * Statistics clock. Grab profile sample, and if divider reaches 0, 394 * do process and kernel statistics. Most of the statistics are only 395 * used by user-level statistics programs. The main exceptions are 396 * ke->ke_uticks, p->p_rux.rux_sticks, p->p_rux.rux_iticks, and p->p_estcpu. 397 * This should be called by all active processors. 398 */ 399 void 400 statclock(int usermode) 401 { 402 struct rusage *ru; 403 struct vmspace *vm; 404 struct thread *td; 405 struct proc *p; 406 long rss; 407 408 td = curthread; 409 p = td->td_proc; 410 411 mtx_lock_spin_flags(&sched_lock, MTX_QUIET); 412 if (usermode) { 413 /* 414 * Charge the time as appropriate. 415 */ 416 if (p->p_flag & P_SA) 417 thread_statclock(1); 418 td->td_uticks++; 419 if (p->p_nice > NZERO) 420 cp_time[CP_NICE]++; 421 else 422 cp_time[CP_USER]++; 423 } else { 424 /* 425 * Came from kernel mode, so we were: 426 * - handling an interrupt, 427 * - doing syscall or trap work on behalf of the current 428 * user process, or 429 * - spinning in the idle loop. 430 * Whichever it is, charge the time as appropriate. 431 * Note that we charge interrupts to the current process, 432 * regardless of whether they are ``for'' that process, 433 * so that we know how much of its real time was spent 434 * in ``non-process'' (i.e., interrupt) work. 435 */ 436 if ((td->td_pflags & TDP_ITHREAD) || 437 td->td_intr_nesting_level >= 2) { 438 td->td_iticks++; 439 cp_time[CP_INTR]++; 440 } else { 441 if (p->p_flag & P_SA) 442 thread_statclock(0); 443 td->td_pticks++; 444 td->td_sticks++; 445 if (td != PCPU_GET(idlethread)) 446 cp_time[CP_SYS]++; 447 else 448 cp_time[CP_IDLE]++; 449 } 450 } 451 CTR4(KTR_SCHED, "statclock: %p(%s) prio %d stathz %d", 452 td, td->td_proc->p_comm, td->td_priority, (stathz)?stathz:hz); 453 454 sched_clock(td); 455 456 /* Update resource usage integrals and maximums. */ 457 MPASS(p->p_stats != NULL); 458 MPASS(p->p_vmspace != NULL); 459 vm = p->p_vmspace; 460 ru = &p->p_stats->p_ru; 461 ru->ru_ixrss += pgtok(vm->vm_tsize); 462 ru->ru_idrss += pgtok(vm->vm_dsize); 463 ru->ru_isrss += pgtok(vm->vm_ssize); 464 rss = pgtok(vmspace_resident_count(vm)); 465 if (ru->ru_maxrss < rss) 466 ru->ru_maxrss = rss; 467 mtx_unlock_spin_flags(&sched_lock, MTX_QUIET); 468 } 469 470 void 471 profclock(int usermode, uintfptr_t pc) 472 { 473 struct thread *td; 474 #ifdef GPROF 475 struct gmonparam *g; 476 uintfptr_t i; 477 #endif 478 479 td = curthread; 480 if (usermode) { 481 /* 482 * Came from user mode; CPU was in user state. 483 * If this process is being profiled, record the tick. 484 * if there is no related user location yet, don't 485 * bother trying to count it. 486 */ 487 if (td->td_proc->p_flag & P_PROFIL) 488 addupc_intr(td, pc, 1); 489 } 490 #ifdef GPROF 491 else { 492 /* 493 * Kernel statistics are just like addupc_intr, only easier. 494 */ 495 g = &_gmonparam; 496 if (g->state == GMON_PROF_ON && pc >= g->lowpc) { 497 i = PC_TO_I(g, pc); 498 if (i < g->textsize) { 499 KCOUNT(g, i)++; 500 } 501 } 502 } 503 #endif 504 } 505 506 /* 507 * Return information about system clocks. 508 */ 509 static int 510 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS) 511 { 512 struct clockinfo clkinfo; 513 /* 514 * Construct clockinfo structure. 515 */ 516 bzero(&clkinfo, sizeof(clkinfo)); 517 clkinfo.hz = hz; 518 clkinfo.tick = tick; 519 clkinfo.profhz = profhz; 520 clkinfo.stathz = stathz ? stathz : hz; 521 return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req)); 522 } 523 524 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD, 525 0, 0, sysctl_kern_clockrate, "S,clockinfo", 526 "Rate and period of various kernel clocks"); 527 528 #ifdef SW_WATCHDOG 529 530 static void 531 watchdog_config(void *unused __unused, u_int cmd, int *err) 532 { 533 u_int u; 534 535 u = cmd & WD_INTERVAL; 536 if ((cmd & WD_ACTIVE) && u >= WD_TO_1SEC) { 537 watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz; 538 watchdog_enabled = 1; 539 *err = 0; 540 } else { 541 watchdog_enabled = 0; 542 } 543 } 544 545 /* 546 * Handle a watchdog timeout by dumping interrupt information and 547 * then either dropping to DDB or panicing. 548 */ 549 static void 550 watchdog_fire(void) 551 { 552 int nintr; 553 u_int64_t inttotal; 554 u_long *curintr; 555 char *curname; 556 557 curintr = intrcnt; 558 curname = intrnames; 559 inttotal = 0; 560 nintr = eintrcnt - intrcnt; 561 562 printf("interrupt total\n"); 563 while (--nintr >= 0) { 564 if (*curintr) 565 printf("%-12s %20lu\n", curname, *curintr); 566 curname += strlen(curname) + 1; 567 inttotal += *curintr++; 568 } 569 printf("Total %20ju\n", (uintmax_t)inttotal); 570 571 #ifdef KDB 572 kdb_backtrace(); 573 kdb_enter("watchdog timeout"); 574 #else 575 panic("watchdog timeout"); 576 #endif /* KDB */ 577 } 578 579 #endif /* SW_WATCHDOG */ 580