1 /* $NetBSD: kern_clock.c,v 1.134 2015/04/22 16:46:58 pooka Exp $ */ 2 3 /*- 4 * Copyright (c) 2000, 2004, 2006, 2007, 2008 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 * 22 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 24 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 25 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 26 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 31 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 32 * POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /*- 36 * Copyright (c) 1982, 1986, 1991, 1993 37 * The Regents of the University of California. All rights reserved. 38 * (c) UNIX System Laboratories, Inc. 39 * All or some portions of this file are derived from material licensed 40 * to the University of California by American Telephone and Telegraph 41 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 42 * the permission of UNIX System Laboratories, Inc. 43 * 44 * Redistribution and use in source and binary forms, with or without 45 * modification, are permitted provided that the following conditions 46 * are met: 47 * 1. Redistributions of source code must retain the above copyright 48 * notice, this list of conditions and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. Neither the name of the University nor the names of its contributors 53 * may be used to endorse or promote products derived from this software 54 * without specific prior written permission. 55 * 56 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 57 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 58 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 59 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 60 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 61 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 62 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 63 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 64 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 65 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 66 * SUCH DAMAGE. 67 * 68 * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 69 */ 70 71 #include <sys/cdefs.h> 72 __KERNEL_RCSID(0, "$NetBSD: kern_clock.c,v 1.134 2015/04/22 16:46:58 pooka Exp $"); 73 74 #ifdef _KERNEL_OPT 75 #include "opt_dtrace.h" 76 #include "opt_perfctrs.h" 77 #endif 78 79 #include <sys/param.h> 80 #include <sys/systm.h> 81 #include <sys/callout.h> 82 #include <sys/kernel.h> 83 #include <sys/proc.h> 84 #include <sys/resourcevar.h> 85 #include <sys/signalvar.h> 86 #include <sys/sysctl.h> 87 #include <sys/timex.h> 88 #include <sys/sched.h> 89 #include <sys/time.h> 90 #include <sys/timetc.h> 91 #include <sys/cpu.h> 92 #include <sys/atomic.h> 93 94 #ifdef GPROF 95 #include <sys/gmon.h> 96 #endif 97 98 #ifdef KDTRACE_HOOKS 99 #include <sys/dtrace_bsd.h> 100 #include <sys/cpu.h> 101 102 cyclic_clock_func_t cyclic_clock_func[MAXCPUS]; 103 #endif 104 105 static int sysctl_kern_clockrate(SYSCTLFN_PROTO); 106 107 /* 108 * Clock handling routines. 109 * 110 * This code is written to operate with two timers that run independently of 111 * each other. The main clock, running hz times per second, is used to keep 112 * track of real time. The second timer handles kernel and user profiling, 113 * and does resource use estimation. If the second timer is programmable, 114 * it is randomized to avoid aliasing between the two clocks. For example, 115 * the randomization prevents an adversary from always giving up the CPU 116 * just before its quantum expires. Otherwise, it would never accumulate 117 * CPU ticks. The mean frequency of the second timer is stathz. 118 * 119 * If no second timer exists, stathz will be zero; in this case we drive 120 * profiling and statistics off the main clock. This WILL NOT be accurate; 121 * do not do it unless absolutely necessary. 122 * 123 * The statistics clock may (or may not) be run at a higher rate while 124 * profiling. This profile clock runs at profhz. We require that profhz 125 * be an integral multiple of stathz. 126 * 127 * If the statistics clock is running fast, it must be divided by the ratio 128 * profhz/stathz for statistics. (For profiling, every tick counts.) 129 */ 130 131 int stathz; 132 int profhz; 133 int profsrc; 134 int schedhz; 135 int profprocs; 136 int hardclock_ticks; 137 static int hardscheddiv; /* hard => sched divider (used if schedhz == 0) */ 138 static int psdiv; /* prof => stat divider */ 139 int psratio; /* ratio: prof / stat */ 140 141 static u_int get_intr_timecount(struct timecounter *); 142 143 static struct timecounter intr_timecounter = { 144 get_intr_timecount, /* get_timecount */ 145 0, /* no poll_pps */ 146 ~0u, /* counter_mask */ 147 0, /* frequency */ 148 "clockinterrupt", /* name */ 149 0, /* quality - minimum implementation level for a clock */ 150 NULL, /* prev */ 151 NULL, /* next */ 152 }; 153 154 static u_int 155 get_intr_timecount(struct timecounter *tc) 156 { 157 158 return (u_int)hardclock_ticks; 159 } 160 161 /* 162 * Initialize clock frequencies and start both clocks running. 163 */ 164 void 165 initclocks(void) 166 { 167 static struct sysctllog *clog; 168 int i; 169 170 /* 171 * Set divisors to 1 (normal case) and let the machine-specific 172 * code do its bit. 173 */ 174 psdiv = 1; 175 /* 176 * provide minimum default time counter 177 * will only run at interrupt resolution 178 */ 179 intr_timecounter.tc_frequency = hz; 180 tc_init(&intr_timecounter); 181 cpu_initclocks(); 182 183 /* 184 * Compute profhz and stathz, fix profhz if needed. 185 */ 186 i = stathz ? stathz : hz; 187 if (profhz == 0) 188 profhz = i; 189 psratio = profhz / i; 190 if (schedhz == 0) { 191 /* 16Hz is best */ 192 hardscheddiv = hz / 16; 193 if (hardscheddiv <= 0) 194 panic("hardscheddiv"); 195 } 196 197 sysctl_createv(&clog, 0, NULL, NULL, 198 CTLFLAG_PERMANENT, 199 CTLTYPE_STRUCT, "clockrate", 200 SYSCTL_DESCR("Kernel clock rates"), 201 sysctl_kern_clockrate, 0, NULL, 202 sizeof(struct clockinfo), 203 CTL_KERN, KERN_CLOCKRATE, CTL_EOL); 204 sysctl_createv(&clog, 0, NULL, NULL, 205 CTLFLAG_PERMANENT, 206 CTLTYPE_INT, "hardclock_ticks", 207 SYSCTL_DESCR("Number of hardclock ticks"), 208 NULL, 0, &hardclock_ticks, sizeof(hardclock_ticks), 209 CTL_KERN, KERN_HARDCLOCK_TICKS, CTL_EOL); 210 } 211 212 /* 213 * The real-time timer, interrupting hz times per second. 214 */ 215 void 216 hardclock(struct clockframe *frame) 217 { 218 struct lwp *l; 219 struct cpu_info *ci; 220 221 ci = curcpu(); 222 l = ci->ci_data.cpu_onproc; 223 224 timer_tick(l, CLKF_USERMODE(frame)); 225 226 /* 227 * If no separate statistics clock is available, run it from here. 228 */ 229 if (stathz == 0) 230 statclock(frame); 231 /* 232 * If no separate schedclock is provided, call it here 233 * at about 16 Hz. 234 */ 235 if (schedhz == 0) { 236 if ((int)(--ci->ci_schedstate.spc_schedticks) <= 0) { 237 schedclock(l); 238 ci->ci_schedstate.spc_schedticks = hardscheddiv; 239 } 240 } 241 if ((--ci->ci_schedstate.spc_ticks) <= 0) 242 sched_tick(ci); 243 244 if (CPU_IS_PRIMARY(ci)) { 245 hardclock_ticks++; 246 tc_ticktock(); 247 } 248 249 /* 250 * Update real-time timeout queue. 251 */ 252 callout_hardclock(); 253 254 #ifdef KDTRACE_HOOKS 255 cyclic_clock_func_t func = cyclic_clock_func[cpu_index(ci)]; 256 if (func) { 257 (*func)((struct clockframe *)frame); 258 } 259 #endif 260 } 261 262 /* 263 * Start profiling on a process. 264 * 265 * Kernel profiling passes proc0 which never exits and hence 266 * keeps the profile clock running constantly. 267 */ 268 void 269 startprofclock(struct proc *p) 270 { 271 272 KASSERT(mutex_owned(&p->p_stmutex)); 273 274 if ((p->p_stflag & PST_PROFIL) == 0) { 275 p->p_stflag |= PST_PROFIL; 276 /* 277 * This is only necessary if using the clock as the 278 * profiling source. 279 */ 280 if (++profprocs == 1 && stathz != 0) 281 psdiv = psratio; 282 } 283 } 284 285 /* 286 * Stop profiling on a process. 287 */ 288 void 289 stopprofclock(struct proc *p) 290 { 291 292 KASSERT(mutex_owned(&p->p_stmutex)); 293 294 if (p->p_stflag & PST_PROFIL) { 295 p->p_stflag &= ~PST_PROFIL; 296 /* 297 * This is only necessary if using the clock as the 298 * profiling source. 299 */ 300 if (--profprocs == 0 && stathz != 0) 301 psdiv = 1; 302 } 303 } 304 305 #if defined(PERFCTRS) 306 /* 307 * Independent profiling "tick" in case we're using a separate 308 * clock or profiling event source. Currently, that's just 309 * performance counters--hence the wrapper. 310 */ 311 void 312 proftick(struct clockframe *frame) 313 { 314 #ifdef GPROF 315 struct gmonparam *g; 316 intptr_t i; 317 #endif 318 struct lwp *l; 319 struct proc *p; 320 321 l = curcpu()->ci_data.cpu_onproc; 322 p = (l ? l->l_proc : NULL); 323 if (CLKF_USERMODE(frame)) { 324 mutex_spin_enter(&p->p_stmutex); 325 if (p->p_stflag & PST_PROFIL) 326 addupc_intr(l, CLKF_PC(frame)); 327 mutex_spin_exit(&p->p_stmutex); 328 } else { 329 #ifdef GPROF 330 g = &_gmonparam; 331 if (g->state == GMON_PROF_ON) { 332 i = CLKF_PC(frame) - g->lowpc; 333 if (i < g->textsize) { 334 i /= HISTFRACTION * sizeof(*g->kcount); 335 g->kcount[i]++; 336 } 337 } 338 #endif 339 #ifdef LWP_PC 340 if (p != NULL && (p->p_stflag & PST_PROFIL) != 0) 341 addupc_intr(l, LWP_PC(l)); 342 #endif 343 } 344 } 345 #endif 346 347 void 348 schedclock(struct lwp *l) 349 { 350 if ((l->l_flag & LW_IDLE) != 0) 351 return; 352 353 sched_schedclock(l); 354 } 355 356 /* 357 * Statistics clock. Grab profile sample, and if divider reaches 0, 358 * do process and kernel statistics. 359 */ 360 void 361 statclock(struct clockframe *frame) 362 { 363 #ifdef GPROF 364 struct gmonparam *g; 365 intptr_t i; 366 #endif 367 struct cpu_info *ci = curcpu(); 368 struct schedstate_percpu *spc = &ci->ci_schedstate; 369 struct proc *p; 370 struct lwp *l; 371 372 /* 373 * Notice changes in divisor frequency, and adjust clock 374 * frequency accordingly. 375 */ 376 if (spc->spc_psdiv != psdiv) { 377 spc->spc_psdiv = psdiv; 378 spc->spc_pscnt = psdiv; 379 if (psdiv == 1) { 380 setstatclockrate(stathz); 381 } else { 382 setstatclockrate(profhz); 383 } 384 } 385 l = ci->ci_data.cpu_onproc; 386 if ((l->l_flag & LW_IDLE) != 0) { 387 /* 388 * don't account idle lwps as swapper. 389 */ 390 p = NULL; 391 } else { 392 p = l->l_proc; 393 mutex_spin_enter(&p->p_stmutex); 394 } 395 396 if (CLKF_USERMODE(frame)) { 397 if ((p->p_stflag & PST_PROFIL) && profsrc == PROFSRC_CLOCK) 398 addupc_intr(l, CLKF_PC(frame)); 399 if (--spc->spc_pscnt > 0) { 400 mutex_spin_exit(&p->p_stmutex); 401 return; 402 } 403 404 /* 405 * Came from user mode; CPU was in user state. 406 * If this process is being profiled record the tick. 407 */ 408 p->p_uticks++; 409 if (p->p_nice > NZERO) 410 spc->spc_cp_time[CP_NICE]++; 411 else 412 spc->spc_cp_time[CP_USER]++; 413 } else { 414 #ifdef GPROF 415 /* 416 * Kernel statistics are just like addupc_intr, only easier. 417 */ 418 g = &_gmonparam; 419 if (profsrc == PROFSRC_CLOCK && g->state == GMON_PROF_ON) { 420 i = CLKF_PC(frame) - g->lowpc; 421 if (i < g->textsize) { 422 i /= HISTFRACTION * sizeof(*g->kcount); 423 g->kcount[i]++; 424 } 425 } 426 #endif 427 #ifdef LWP_PC 428 if (p != NULL && profsrc == PROFSRC_CLOCK && 429 (p->p_stflag & PST_PROFIL)) { 430 addupc_intr(l, LWP_PC(l)); 431 } 432 #endif 433 if (--spc->spc_pscnt > 0) { 434 if (p != NULL) 435 mutex_spin_exit(&p->p_stmutex); 436 return; 437 } 438 /* 439 * Came from kernel mode, so we were: 440 * - handling an interrupt, 441 * - doing syscall or trap work on behalf of the current 442 * user process, or 443 * - spinning in the idle loop. 444 * Whichever it is, charge the time as appropriate. 445 * Note that we charge interrupts to the current process, 446 * regardless of whether they are ``for'' that process, 447 * so that we know how much of its real time was spent 448 * in ``non-process'' (i.e., interrupt) work. 449 */ 450 if (CLKF_INTR(frame) || (curlwp->l_pflag & LP_INTR) != 0) { 451 if (p != NULL) { 452 p->p_iticks++; 453 } 454 spc->spc_cp_time[CP_INTR]++; 455 } else if (p != NULL) { 456 p->p_sticks++; 457 spc->spc_cp_time[CP_SYS]++; 458 } else { 459 spc->spc_cp_time[CP_IDLE]++; 460 } 461 } 462 spc->spc_pscnt = psdiv; 463 464 if (p != NULL) { 465 atomic_inc_uint(&l->l_cpticks); 466 mutex_spin_exit(&p->p_stmutex); 467 } 468 } 469 470 /* 471 * sysctl helper routine for kern.clockrate. Assembles a struct on 472 * the fly to be returned to the caller. 473 */ 474 static int 475 sysctl_kern_clockrate(SYSCTLFN_ARGS) 476 { 477 struct clockinfo clkinfo; 478 struct sysctlnode node; 479 480 clkinfo.tick = tick; 481 clkinfo.tickadj = tickadj; 482 clkinfo.hz = hz; 483 clkinfo.profhz = profhz; 484 clkinfo.stathz = stathz ? stathz : hz; 485 486 node = *rnode; 487 node.sysctl_data = &clkinfo; 488 return (sysctl_lookup(SYSCTLFN_CALL(&node))); 489 } 490