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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 39 * $FreeBSD$ 40 */ 41 42 #include "opt_ntp.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/dkstat.h> 47 #include <sys/callout.h> 48 #include <sys/kernel.h> 49 #include <sys/lock.h> 50 #include <sys/ktr.h> 51 #include <sys/mutex.h> 52 #include <sys/proc.h> 53 #include <sys/resourcevar.h> 54 #include <sys/signalvar.h> 55 #include <sys/smp.h> 56 #include <vm/vm.h> 57 #include <vm/pmap.h> 58 #include <vm/vm_map.h> 59 #include <sys/sysctl.h> 60 #include <sys/bus.h> 61 #include <sys/interrupt.h> 62 63 #include <machine/cpu.h> 64 #include <machine/limits.h> 65 66 #ifdef GPROF 67 #include <sys/gmon.h> 68 #endif 69 70 #ifdef DEVICE_POLLING 71 extern void init_device_poll(void); 72 extern void hardclock_device_poll(void); 73 #endif /* DEVICE_POLLING */ 74 75 static void initclocks(void *dummy); 76 SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL) 77 78 /* Some of these don't belong here, but it's easiest to concentrate them. */ 79 long cp_time[CPUSTATES]; 80 81 SYSCTL_OPAQUE(_kern, OID_AUTO, cp_time, CTLFLAG_RD, &cp_time, sizeof(cp_time), 82 "LU", "CPU time statistics"); 83 84 long tk_cancc; 85 long tk_nin; 86 long tk_nout; 87 long tk_rawcc; 88 89 /* 90 * Clock handling routines. 91 * 92 * This code is written to operate with two timers that run independently of 93 * each other. 94 * 95 * The main timer, running hz times per second, is used to trigger interval 96 * timers, timeouts and rescheduling as needed. 97 * 98 * The second timer handles kernel and user profiling, 99 * and does resource use estimation. If the second timer is programmable, 100 * it is randomized to avoid aliasing between the two clocks. For example, 101 * the randomization prevents an adversary from always giving up the cpu 102 * just before its quantum expires. Otherwise, it would never accumulate 103 * cpu ticks. The mean frequency of the second timer is stathz. 104 * 105 * If no second timer exists, stathz will be zero; in this case we drive 106 * profiling and statistics off the main clock. This WILL NOT be accurate; 107 * do not do it unless absolutely necessary. 108 * 109 * The statistics clock may (or may not) be run at a higher rate while 110 * profiling. This profile clock runs at profhz. We require that profhz 111 * be an integral multiple of stathz. 112 * 113 * If the statistics clock is running fast, it must be divided by the ratio 114 * profhz/stathz for statistics. (For profiling, every tick counts.) 115 * 116 * Time-of-day is maintained using a "timecounter", which may or may 117 * not be related to the hardware generating the above mentioned 118 * interrupts. 119 */ 120 121 int stathz; 122 int profhz; 123 static int profprocs; 124 int ticks; 125 static int psdiv, pscnt; /* prof => stat divider */ 126 int psratio; /* ratio: prof / stat */ 127 128 /* 129 * Initialize clock frequencies and start both clocks running. 130 */ 131 /* ARGSUSED*/ 132 static void 133 initclocks(dummy) 134 void *dummy; 135 { 136 register int i; 137 138 /* 139 * Set divisors to 1 (normal case) and let the machine-specific 140 * code do its bit. 141 */ 142 psdiv = pscnt = 1; 143 cpu_initclocks(); 144 145 #ifdef DEVICE_POLLING 146 init_device_poll(); 147 #endif 148 /* 149 * Compute profhz/stathz, and fix profhz if needed. 150 */ 151 i = stathz ? stathz : hz; 152 if (profhz == 0) 153 profhz = i; 154 psratio = profhz / i; 155 } 156 157 /* 158 * Each time the real-time timer fires, this function is called on all CPUs 159 * with each CPU passing in its curthread as the first argument. If possible 160 * a nice optimization in the future would be to allow the CPU receiving the 161 * actual real-time timer interrupt to call this function on behalf of the 162 * other CPUs rather than sending an IPI to all other CPUs so that they 163 * can call this function. Note that hardclock() calls hardclock_process() 164 * for the CPU receiving the timer interrupt, so only the other CPUs in the 165 * system need to call this function (or have it called on their behalf. 166 */ 167 void 168 hardclock_process(td, user) 169 struct thread *td; 170 int user; 171 { 172 struct pstats *pstats; 173 struct proc *p = td->td_proc; 174 175 /* 176 * Run current process's virtual and profile time, as needed. 177 */ 178 mtx_assert(&sched_lock, MA_OWNED); 179 if (p->p_flag & P_KSES) { 180 /* XXXKSE What to do? */ 181 } else { 182 pstats = p->p_stats; 183 if (user && 184 timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) && 185 itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) { 186 p->p_sflag |= PS_ALRMPEND; 187 td->td_kse->ke_flags |= KEF_ASTPENDING; 188 } 189 if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value) && 190 itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) { 191 p->p_sflag |= PS_PROFPEND; 192 td->td_kse->ke_flags |= KEF_ASTPENDING; 193 } 194 } 195 } 196 197 /* 198 * The real-time timer, interrupting hz times per second. 199 */ 200 void 201 hardclock(frame) 202 register struct clockframe *frame; 203 { 204 int need_softclock = 0; 205 206 CTR0(KTR_CLK, "hardclock fired"); 207 mtx_lock_spin_flags(&sched_lock, MTX_QUIET); 208 hardclock_process(curthread, CLKF_USERMODE(frame)); 209 mtx_unlock_spin_flags(&sched_lock, MTX_QUIET); 210 211 /* 212 * If no separate statistics clock is available, run it from here. 213 * 214 * XXX: this only works for UP 215 */ 216 if (stathz == 0) 217 statclock(frame); 218 219 #ifdef DEVICE_POLLING 220 hardclock_device_poll(); /* this is very short and quick */ 221 #endif /* DEVICE_POLLING */ 222 223 /* 224 * Process callouts at a very low cpu priority, so we don't keep the 225 * relatively high clock interrupt priority any longer than necessary. 226 */ 227 mtx_lock_spin_flags(&callout_lock, MTX_QUIET); 228 ticks++; 229 if (TAILQ_FIRST(&callwheel[ticks & callwheelmask]) != NULL) { 230 need_softclock = 1; 231 } else if (softticks + 1 == ticks) 232 ++softticks; 233 mtx_unlock_spin_flags(&callout_lock, MTX_QUIET); 234 235 /* 236 * swi_sched acquires sched_lock, so we don't want to call it with 237 * callout_lock held; incorrect locking order. 238 */ 239 if (need_softclock) 240 swi_sched(softclock_ih, 0); 241 } 242 243 /* 244 * Compute number of ticks in the specified amount of time. 245 */ 246 int 247 tvtohz(tv) 248 struct timeval *tv; 249 { 250 register unsigned long ticks; 251 register long sec, usec; 252 253 /* 254 * If the number of usecs in the whole seconds part of the time 255 * difference fits in a long, then the total number of usecs will 256 * fit in an unsigned long. Compute the total and convert it to 257 * ticks, rounding up and adding 1 to allow for the current tick 258 * to expire. Rounding also depends on unsigned long arithmetic 259 * to avoid overflow. 260 * 261 * Otherwise, if the number of ticks in the whole seconds part of 262 * the time difference fits in a long, then convert the parts to 263 * ticks separately and add, using similar rounding methods and 264 * overflow avoidance. This method would work in the previous 265 * case but it is slightly slower and assumes that hz is integral. 266 * 267 * Otherwise, round the time difference down to the maximum 268 * representable value. 269 * 270 * If ints have 32 bits, then the maximum value for any timeout in 271 * 10ms ticks is 248 days. 272 */ 273 sec = tv->tv_sec; 274 usec = tv->tv_usec; 275 if (usec < 0) { 276 sec--; 277 usec += 1000000; 278 } 279 if (sec < 0) { 280 #ifdef DIAGNOSTIC 281 if (usec > 0) { 282 sec++; 283 usec -= 1000000; 284 } 285 printf("tvotohz: negative time difference %ld sec %ld usec\n", 286 sec, usec); 287 #endif 288 ticks = 1; 289 } else if (sec <= LONG_MAX / 1000000) 290 ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1)) 291 / tick + 1; 292 else if (sec <= LONG_MAX / hz) 293 ticks = sec * hz 294 + ((unsigned long)usec + (tick - 1)) / tick + 1; 295 else 296 ticks = LONG_MAX; 297 if (ticks > INT_MAX) 298 ticks = INT_MAX; 299 return ((int)ticks); 300 } 301 302 /* 303 * Start profiling on a process. 304 * 305 * Kernel profiling passes proc0 which never exits and hence 306 * keeps the profile clock running constantly. 307 */ 308 void 309 startprofclock(p) 310 register struct proc *p; 311 { 312 int s; 313 314 /* 315 * XXX; Right now sched_lock protects statclock(), but perhaps 316 * it should be protected later on by a time_lock, which would 317 * cover psdiv, etc. as well. 318 */ 319 mtx_lock_spin(&sched_lock); 320 if ((p->p_sflag & PS_PROFIL) == 0) { 321 p->p_sflag |= PS_PROFIL; 322 if (++profprocs == 1 && stathz != 0) { 323 s = splstatclock(); 324 psdiv = pscnt = psratio; 325 setstatclockrate(profhz); 326 splx(s); 327 } 328 } 329 mtx_unlock_spin(&sched_lock); 330 } 331 332 /* 333 * Stop profiling on a process. 334 */ 335 void 336 stopprofclock(p) 337 register struct proc *p; 338 { 339 int s; 340 341 mtx_lock_spin(&sched_lock); 342 if (p->p_sflag & PS_PROFIL) { 343 p->p_sflag &= ~PS_PROFIL; 344 if (--profprocs == 0 && stathz != 0) { 345 s = splstatclock(); 346 psdiv = pscnt = 1; 347 setstatclockrate(stathz); 348 splx(s); 349 } 350 } 351 mtx_unlock_spin(&sched_lock); 352 } 353 354 /* 355 * Do process and kernel statistics. Most of the statistics are only 356 * used by user-level statistics programs. The main exceptions are 357 * ke->ke_uticks, p->p_sticks, p->p_iticks, and p->p_estcpu. This function 358 * should be called by all CPUs in the system for each statistics clock 359 * interrupt. See the description of hardclock_process for more detail on 360 * this function's relationship to statclock. 361 */ 362 void 363 statclock_process(ke, pc, user) 364 struct kse *ke; 365 register_t pc; 366 int user; 367 { 368 #ifdef GPROF 369 struct gmonparam *g; 370 int i; 371 #endif 372 struct pstats *pstats; 373 long rss; 374 struct rusage *ru; 375 struct vmspace *vm; 376 struct proc *p = ke->ke_proc; 377 struct thread *td = ke->ke_thread; /* current thread */ 378 379 KASSERT(ke == curthread->td_kse, ("statclock_process: td != curthread")); 380 mtx_assert(&sched_lock, MA_OWNED); 381 if (user) { 382 /* 383 * Came from user mode; CPU was in user state. 384 * If this process is being profiled, record the tick. 385 */ 386 if (p->p_sflag & PS_PROFIL) 387 addupc_intr(ke, pc, 1); 388 if (pscnt < psdiv) 389 return; 390 /* 391 * Charge the time as appropriate. 392 */ 393 ke->ke_uticks++; 394 if (ke->ke_ksegrp->kg_nice > NZERO) 395 cp_time[CP_NICE]++; 396 else 397 cp_time[CP_USER]++; 398 } else { 399 #ifdef GPROF 400 /* 401 * Kernel statistics are just like addupc_intr, only easier. 402 */ 403 g = &_gmonparam; 404 if (g->state == GMON_PROF_ON) { 405 i = pc - g->lowpc; 406 if (i < g->textsize) { 407 i /= HISTFRACTION * sizeof(*g->kcount); 408 g->kcount[i]++; 409 } 410 } 411 #endif 412 if (pscnt < psdiv) 413 return; 414 /* 415 * Came from kernel mode, so we were: 416 * - handling an interrupt, 417 * - doing syscall or trap work on behalf of the current 418 * user process, or 419 * - spinning in the idle loop. 420 * Whichever it is, charge the time as appropriate. 421 * Note that we charge interrupts to the current process, 422 * regardless of whether they are ``for'' that process, 423 * so that we know how much of its real time was spent 424 * in ``non-process'' (i.e., interrupt) work. 425 */ 426 if ((td->td_ithd != NULL) || td->td_intr_nesting_level >= 2) { 427 ke->ke_iticks++; 428 cp_time[CP_INTR]++; 429 } else { 430 ke->ke_sticks++; 431 if (p != PCPU_GET(idlethread)->td_proc) 432 cp_time[CP_SYS]++; 433 else 434 cp_time[CP_IDLE]++; 435 } 436 } 437 438 schedclock(ke->ke_thread); 439 440 /* Update resource usage integrals and maximums. */ 441 if ((pstats = p->p_stats) != NULL && 442 (ru = &pstats->p_ru) != NULL && 443 (vm = p->p_vmspace) != NULL) { 444 ru->ru_ixrss += pgtok(vm->vm_tsize); 445 ru->ru_idrss += pgtok(vm->vm_dsize); 446 ru->ru_isrss += pgtok(vm->vm_ssize); 447 rss = pgtok(vmspace_resident_count(vm)); 448 if (ru->ru_maxrss < rss) 449 ru->ru_maxrss = rss; 450 } 451 } 452 453 /* 454 * Statistics clock. Grab profile sample, and if divider reaches 0, 455 * do process and kernel statistics. Most of the statistics are only 456 * used by user-level statistics programs. The main exceptions are 457 * ke->ke_uticks, p->p_sticks, p->p_iticks, and p->p_estcpu. 458 */ 459 void 460 statclock(frame) 461 register struct clockframe *frame; 462 { 463 464 CTR0(KTR_CLK, "statclock fired"); 465 mtx_lock_spin_flags(&sched_lock, MTX_QUIET); 466 if (--pscnt == 0) 467 pscnt = psdiv; 468 statclock_process(curthread->td_kse, CLKF_PC(frame), CLKF_USERMODE(frame)); 469 mtx_unlock_spin_flags(&sched_lock, MTX_QUIET); 470 } 471 472 /* 473 * Return information about system clocks. 474 */ 475 static int 476 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS) 477 { 478 struct clockinfo clkinfo; 479 /* 480 * Construct clockinfo structure. 481 */ 482 bzero(&clkinfo, sizeof(clkinfo)); 483 clkinfo.hz = hz; 484 clkinfo.tick = tick; 485 clkinfo.profhz = profhz; 486 clkinfo.stathz = stathz ? stathz : hz; 487 return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req)); 488 } 489 490 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD, 491 0, 0, sysctl_kern_clockrate, "S,clockinfo", 492 "Rate and period of various kernel clocks"); 493