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 | |