1 /* $NetBSD: kern_clock.c,v 1.127 2010/12/20 00:25:46 matt 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 1.127 2010/12/20 00:25:46 matt Exp $"); 73 74 #include "opt_ntp.h" 75 #include "opt_perfctrs.h" 76 77 #include <sys/param.h> 78 #include <sys/systm.h> 79 #include <sys/callout.h> 80 #include <sys/kernel.h> 81 #include <sys/proc.h> 82 #include <sys/resourcevar.h> 83 #include <sys/signalvar.h> 84 #include <sys/sysctl.h> 85 #include <sys/timex.h> 86 #include <sys/sched.h> 87 #include <sys/time.h> 88 #include <sys/timetc.h> 89 #include <sys/cpu.h> 90 #include <sys/atomic.h> 91 92 #include <uvm/uvm_extern.h> 93 94 #ifdef GPROF 95 #include <sys/gmon.h> 96 #endif 97 98 /* 99 * Clock handling routines. 100 * 101 * This code is written to operate with two timers that run independently of 102 * each other. The main clock, running hz times per second, is used to keep 103 * track of real time. The second timer handles kernel and user profiling, 104 * and does resource use estimation. If the second timer is programmable, 105 * it is randomized to avoid aliasing between the two clocks. For example, 106 * the randomization prevents an adversary from always giving up the CPU 107 * just before its quantum expires. Otherwise, it would never accumulate 108 * CPU ticks. The mean frequency of the second timer is stathz. 109 * 110 * If no second timer exists, stathz will be zero; in this case we drive 111 * profiling and statistics off the main clock. This WILL NOT be accurate; 112 * do not do it unless absolutely necessary. 113 * 114 * The statistics clock may (or may not) be run at a higher rate while 115 * profiling. This profile clock runs at profhz. We require that profhz 116 * be an integral multiple of stathz. 117 * 118 * If the statistics clock is running fast, it must be divided by the ratio 119 * profhz/stathz for statistics. (For profiling, every tick counts.) 120 */ 121 122 int stathz; 123 int profhz; 124 int profsrc; 125 int schedhz; 126 int profprocs; 127 int hardclock_ticks; 128 static int hardscheddiv; /* hard => sched divider (used if schedhz == 0) */ 129 static int psdiv; /* prof => stat divider */ 130 int psratio; /* ratio: prof / stat */ 131 132 static u_int get_intr_timecount(struct timecounter *); 133 134 static struct timecounter intr_timecounter = { 135 get_intr_timecount, /* get_timecount */ 136 0, /* no poll_pps */ 137 ~0u, /* counter_mask */ 138 0, /* frequency */ 139 "clockinterrupt", /* name */ 140 0, /* quality - minimum implementation level for a clock */ 141 NULL, /* prev */ 142 NULL, /* next */ 143 }; 144 145 static u_int 146 get_intr_timecount(struct timecounter *tc) 147 { 148 149 return (u_int)hardclock_ticks; 150 } 151 152 /* 153 * Initialize clock frequencies and start both clocks running. 154 */ 155 void 156 initclocks(void) 157 { 158 int i; 159 160 /* 161 * Set divisors to 1 (normal case) and let the machine-specific 162 * code do its bit. 163 */ 164 psdiv = 1; 165 /* 166 * provide minimum default time counter 167 * will only run at interrupt resolution 168 */ 169 intr_timecounter.tc_frequency = hz; 170 tc_init(&intr_timecounter); 171 cpu_initclocks(); 172 173 /* 174 * Compute profhz and stathz, fix profhz if needed. 175 */ 176 i = stathz ? stathz : hz; 177 if (profhz == 0) 178 profhz = i; 179 psratio = profhz / i; 180 if (schedhz == 0) { 181 /* 16Hz is best */ 182 hardscheddiv = hz / 16; 183 if (hardscheddiv <= 0) 184 panic("hardscheddiv"); 185 } 186 187 } 188 189 /* 190 * The real-time timer, interrupting hz times per second. 191 */ 192 void 193 hardclock(struct clockframe *frame) 194 { 195 struct lwp *l; 196 struct cpu_info *ci; 197 198 ci = curcpu(); 199 l = ci->ci_data.cpu_onproc; 200 201 timer_tick(l, CLKF_USERMODE(frame)); 202 203 /* 204 * If no separate statistics clock is available, run it from here. 205 */ 206 if (stathz == 0) 207 statclock(frame); 208 /* 209 * If no separate schedclock is provided, call it here 210 * at about 16 Hz. 211 */ 212 if (schedhz == 0) { 213 if ((int)(--ci->ci_schedstate.spc_schedticks) <= 0) { 214 schedclock(l); 215 ci->ci_schedstate.spc_schedticks = hardscheddiv; 216 } 217 } 218 if ((--ci->ci_schedstate.spc_ticks) <= 0) 219 sched_tick(ci); 220 221 if (CPU_IS_PRIMARY(ci)) { 222 hardclock_ticks++; 223 tc_ticktock(); 224 } 225 226 /* 227 * Update real-time timeout queue. 228 */ 229 callout_hardclock(); 230 } 231 232 /* 233 * Start profiling on a process. 234 * 235 * Kernel profiling passes proc0 which never exits and hence 236 * keeps the profile clock running constantly. 237 */ 238 void 239 startprofclock(struct proc *p) 240 { 241 242 KASSERT(mutex_owned(&p->p_stmutex)); 243 244 if ((p->p_stflag & PST_PROFIL) == 0) { 245 p->p_stflag |= PST_PROFIL; 246 /* 247 * This is only necessary if using the clock as the 248 * profiling source. 249 */ 250 if (++profprocs == 1 && stathz != 0) 251 psdiv = psratio; 252 } 253 } 254 255 /* 256 * Stop profiling on a process. 257 */ 258 void 259 stopprofclock(struct proc *p) 260 { 261 262 KASSERT(mutex_owned(&p->p_stmutex)); 263 264 if (p->p_stflag & PST_PROFIL) { 265 p->p_stflag &= ~PST_PROFIL; 266 /* 267 * This is only necessary if using the clock as the 268 * profiling source. 269 */ 270 if (--profprocs == 0 && stathz != 0) 271 psdiv = 1; 272 } 273 } 274 275 #if defined(PERFCTRS) 276 /* 277 * Independent profiling "tick" in case we're using a separate 278 * clock or profiling event source. Currently, that's just 279 * performance counters--hence the wrapper. 280 */ 281 void 282 proftick(struct clockframe *frame) 283 { 284 #ifdef GPROF 285 struct gmonparam *g; 286 intptr_t i; 287 #endif 288 struct lwp *l; 289 struct proc *p; 290 291 l = curcpu()->ci_data.cpu_onproc; 292 p = (l ? l->l_proc : NULL); 293 if (CLKF_USERMODE(frame)) { 294 mutex_spin_enter(&p->p_stmutex); 295 if (p->p_stflag & PST_PROFIL) 296 addupc_intr(l, CLKF_PC(frame)); 297 mutex_spin_exit(&p->p_stmutex); 298 } else { 299 #ifdef GPROF 300 g = &_gmonparam; 301 if (g->state == GMON_PROF_ON) { 302 i = CLKF_PC(frame) - g->lowpc; 303 if (i < g->textsize) { 304 i /= HISTFRACTION * sizeof(*g->kcount); 305 g->kcount[i]++; 306 } 307 } 308 #endif 309 #ifdef LWP_PC 310 if (p != NULL && (p->p_stflag & PST_PROFIL) != 0) 311 addupc_intr(l, LWP_PC(l)); 312 #endif 313 } 314 } 315 #endif 316 317 void 318 schedclock(struct lwp *l) 319 { 320 if ((l->l_flag & LW_IDLE) != 0) 321 return; 322 323 sched_schedclock(l); 324 } 325 326 /* 327 * Statistics clock. Grab profile sample, and if divider reaches 0, 328 * do process and kernel statistics. 329 */ 330 void 331 statclock(struct clockframe *frame) 332 { 333 #ifdef GPROF 334 struct gmonparam *g; 335 intptr_t i; 336 #endif 337 struct cpu_info *ci = curcpu(); 338 struct schedstate_percpu *spc = &ci->ci_schedstate; 339 struct proc *p; 340 struct lwp *l; 341 342 /* 343 * Notice changes in divisor frequency, and adjust clock 344 * frequency accordingly. 345 */ 346 if (spc->spc_psdiv != psdiv) { 347 spc->spc_psdiv = psdiv; 348 spc->spc_pscnt = psdiv; 349 if (psdiv == 1) { 350 setstatclockrate(stathz); 351 } else { 352 setstatclockrate(profhz); 353 } 354 } 355 l = ci->ci_data.cpu_onproc; 356 if ((l->l_flag & LW_IDLE) != 0) { 357 /* 358 * don't account idle lwps as swapper. 359 */ 360 p = NULL; 361 } else { 362 p = l->l_proc; 363 mutex_spin_enter(&p->p_stmutex); 364 } 365 366 if (CLKF_USERMODE(frame)) { 367 if ((p->p_stflag & PST_PROFIL) && profsrc == PROFSRC_CLOCK) 368 addupc_intr(l, CLKF_PC(frame)); 369 if (--spc->spc_pscnt > 0) { 370 mutex_spin_exit(&p->p_stmutex); 371 return; 372 } 373 374 /* 375 * Came from user mode; CPU was in user state. 376 * If this process is being profiled record the tick. 377 */ 378 p->p_uticks++; 379 if (p->p_nice > NZERO) 380 spc->spc_cp_time[CP_NICE]++; 381 else 382 spc->spc_cp_time[CP_USER]++; 383 } else { 384 #ifdef GPROF 385 /* 386 * Kernel statistics are just like addupc_intr, only easier. 387 */ 388 g = &_gmonparam; 389 if (profsrc == PROFSRC_CLOCK && g->state == GMON_PROF_ON) { 390 i = CLKF_PC(frame) - g->lowpc; 391 if (i < g->textsize) { 392 i /= HISTFRACTION * sizeof(*g->kcount); 393 g->kcount[i]++; 394 } 395 } 396 #endif 397 #ifdef LWP_PC 398 if (p != NULL && profsrc == PROFSRC_CLOCK && 399 (p->p_stflag & PST_PROFIL)) { 400 addupc_intr(l, LWP_PC(l)); 401 } 402 #endif 403 if (--spc->spc_pscnt > 0) { 404 if (p != NULL) 405 mutex_spin_exit(&p->p_stmutex); 406 return; 407 } 408 /* 409 * Came from kernel mode, so we were: 410 * - handling an interrupt, 411 * - doing syscall or trap work on behalf of the current 412 * user process, or 413 * - spinning in the idle loop. 414 * Whichever it is, charge the time as appropriate. 415 * Note that we charge interrupts to the current process, 416 * regardless of whether they are ``for'' that process, 417 * so that we know how much of its real time was spent 418 * in ``non-process'' (i.e., interrupt) work. 419 */ 420 if (CLKF_INTR(frame) || (curlwp->l_pflag & LP_INTR) != 0) { 421 if (p != NULL) { 422 p->p_iticks++; 423 } 424 spc->spc_cp_time[CP_INTR]++; 425 } else if (p != NULL) { 426 p->p_sticks++; 427 spc->spc_cp_time[CP_SYS]++; 428 } else { 429 spc->spc_cp_time[CP_IDLE]++; 430 } 431 } 432 spc->spc_pscnt = psdiv; 433 434 if (p != NULL) { 435 atomic_inc_uint(&l->l_cpticks); 436 mutex_spin_exit(&p->p_stmutex); 437 } 438 } 439