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subr_prof.c (72912) subr_prof.c (74903)
1/*-
2 * Copyright (c) 1982, 1986, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)subr_prof.c 8.3 (Berkeley) 9/23/93
1/*-
2 * Copyright (c) 1982, 1986, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)subr_prof.c 8.3 (Berkeley) 9/23/93
34 * $FreeBSD: head/sys/kern/subr_prof.c 72912 2001-02-22 18:07:31Z jhb $
34 * $FreeBSD: head/sys/kern/subr_prof.c 74903 2001-03-28 03:06:10Z jhb $
35 */
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/sysproto.h>
40#include <sys/ipl.h>
41#include <sys/kernel.h>
42#include <sys/proc.h>
43#include <sys/resourcevar.h>
44#include <sys/sysctl.h>
45
46#include <machine/cpu.h>
47
48#ifdef GPROF
49#include <sys/malloc.h>
50#include <sys/gmon.h>
51#undef MCOUNT
52
53static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer");
54
55static void kmstartup __P((void *));
56SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL)
57
58struct gmonparam _gmonparam = { GMON_PROF_OFF };
59
60#ifdef GUPROF
61#include <machine/asmacros.h>
62
63void
64nullfunc_loop_profiled()
65{
66 int i;
67
68 for (i = 0; i < CALIB_SCALE; i++)
69 nullfunc_profiled();
70}
71
72#define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */
73
74void
75nullfunc_profiled()
76{
77}
78#endif /* GUPROF */
79
80static void
81kmstartup(dummy)
82 void *dummy;
83{
84 char *cp;
85 struct gmonparam *p = &_gmonparam;
86#ifdef GUPROF
87 int cputime_overhead;
88 int empty_loop_time;
89 int i;
90 int mcount_overhead;
91 int mexitcount_overhead;
92 int nullfunc_loop_overhead;
93 int nullfunc_loop_profiled_time;
94 uintfptr_t tmp_addr;
35 */
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/sysproto.h>
40#include <sys/ipl.h>
41#include <sys/kernel.h>
42#include <sys/proc.h>
43#include <sys/resourcevar.h>
44#include <sys/sysctl.h>
45
46#include <machine/cpu.h>
47
48#ifdef GPROF
49#include <sys/malloc.h>
50#include <sys/gmon.h>
51#undef MCOUNT
52
53static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer");
54
55static void kmstartup __P((void *));
56SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL)
57
58struct gmonparam _gmonparam = { GMON_PROF_OFF };
59
60#ifdef GUPROF
61#include <machine/asmacros.h>
62
63void
64nullfunc_loop_profiled()
65{
66 int i;
67
68 for (i = 0; i < CALIB_SCALE; i++)
69 nullfunc_profiled();
70}
71
72#define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */
73
74void
75nullfunc_profiled()
76{
77}
78#endif /* GUPROF */
79
80static void
81kmstartup(dummy)
82 void *dummy;
83{
84 char *cp;
85 struct gmonparam *p = &_gmonparam;
86#ifdef GUPROF
87 int cputime_overhead;
88 int empty_loop_time;
89 int i;
90 int mcount_overhead;
91 int mexitcount_overhead;
92 int nullfunc_loop_overhead;
93 int nullfunc_loop_profiled_time;
94 uintfptr_t tmp_addr;
95 int intrstate;
95 critical_t savecrit;
96#endif
97
98 /*
99 * Round lowpc and highpc to multiples of the density we're using
100 * so the rest of the scaling (here and in gprof) stays in ints.
101 */
102 p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER));
103 p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER));
104 p->textsize = p->highpc - p->lowpc;
105 printf("Profiling kernel, textsize=%lu [%x..%x]\n",
106 p->textsize, p->lowpc, p->highpc);
107 p->kcountsize = p->textsize / HISTFRACTION;
108 p->hashfraction = HASHFRACTION;
109 p->fromssize = p->textsize / HASHFRACTION;
110 p->tolimit = p->textsize * ARCDENSITY / 100;
111 if (p->tolimit < MINARCS)
112 p->tolimit = MINARCS;
113 else if (p->tolimit > MAXARCS)
114 p->tolimit = MAXARCS;
115 p->tossize = p->tolimit * sizeof(struct tostruct);
116 cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize,
117 M_GPROF, M_NOWAIT | M_ZERO);
118 if (cp == 0) {
119 printf("No memory for profiling.\n");
120 return;
121 }
122 p->tos = (struct tostruct *)cp;
123 cp += p->tossize;
124 p->kcount = (HISTCOUNTER *)cp;
125 cp += p->kcountsize;
126 p->froms = (u_short *)cp;
127
128#ifdef GUPROF
129 /* Initialize pointers to overhead counters. */
130 p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime));
131 p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount));
132 p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount));
133
134 /*
135 * Disable interrupts to avoid interference while we calibrate
136 * things.
137 */
96#endif
97
98 /*
99 * Round lowpc and highpc to multiples of the density we're using
100 * so the rest of the scaling (here and in gprof) stays in ints.
101 */
102 p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER));
103 p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER));
104 p->textsize = p->highpc - p->lowpc;
105 printf("Profiling kernel, textsize=%lu [%x..%x]\n",
106 p->textsize, p->lowpc, p->highpc);
107 p->kcountsize = p->textsize / HISTFRACTION;
108 p->hashfraction = HASHFRACTION;
109 p->fromssize = p->textsize / HASHFRACTION;
110 p->tolimit = p->textsize * ARCDENSITY / 100;
111 if (p->tolimit < MINARCS)
112 p->tolimit = MINARCS;
113 else if (p->tolimit > MAXARCS)
114 p->tolimit = MAXARCS;
115 p->tossize = p->tolimit * sizeof(struct tostruct);
116 cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize,
117 M_GPROF, M_NOWAIT | M_ZERO);
118 if (cp == 0) {
119 printf("No memory for profiling.\n");
120 return;
121 }
122 p->tos = (struct tostruct *)cp;
123 cp += p->tossize;
124 p->kcount = (HISTCOUNTER *)cp;
125 cp += p->kcountsize;
126 p->froms = (u_short *)cp;
127
128#ifdef GUPROF
129 /* Initialize pointers to overhead counters. */
130 p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime));
131 p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount));
132 p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount));
133
134 /*
135 * Disable interrupts to avoid interference while we calibrate
136 * things.
137 */
138 intrstate = save_intr();
139 disable_intr();
138 savecrit = critical_enter();
140
141 /*
142 * Determine overheads.
143 * XXX this needs to be repeated for each useful timer/counter.
144 */
145 cputime_overhead = 0;
146 startguprof(p);
147 for (i = 0; i < CALIB_SCALE; i++)
148 cputime_overhead += cputime();
149
150 empty_loop();
151 startguprof(p);
152 empty_loop();
153 empty_loop_time = cputime();
154
155 nullfunc_loop_profiled();
156
157 /*
158 * Start profiling. There won't be any normal function calls since
159 * interrupts are disabled, but we will call the profiling routines
160 * directly to determine their overheads.
161 */
162 p->state = GMON_PROF_HIRES;
163
164 startguprof(p);
165 nullfunc_loop_profiled();
166
167 startguprof(p);
168 for (i = 0; i < CALIB_SCALE; i++)
169#if defined(__i386__) && __GNUC__ >= 2
170 __asm("pushl %0; call __mcount; popl %%ecx"
171 :
172 : "i" (profil)
173 : "ax", "bx", "cx", "dx", "memory");
174#else
175#error
176#endif
177 mcount_overhead = KCOUNT(p, PC_TO_I(p, profil));
178
179 startguprof(p);
180 for (i = 0; i < CALIB_SCALE; i++)
181#if defined(__i386__) && __GNUC__ >= 2
182 __asm("call " __XSTRING(HIDENAME(mexitcount)) "; 1:"
183 : : : "ax", "bx", "cx", "dx", "memory");
184 __asm("movl $1b,%0" : "=rm" (tmp_addr));
185#else
186#error
187#endif
188 mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr));
189
190 p->state = GMON_PROF_OFF;
191 stopguprof(p);
192
139
140 /*
141 * Determine overheads.
142 * XXX this needs to be repeated for each useful timer/counter.
143 */
144 cputime_overhead = 0;
145 startguprof(p);
146 for (i = 0; i < CALIB_SCALE; i++)
147 cputime_overhead += cputime();
148
149 empty_loop();
150 startguprof(p);
151 empty_loop();
152 empty_loop_time = cputime();
153
154 nullfunc_loop_profiled();
155
156 /*
157 * Start profiling. There won't be any normal function calls since
158 * interrupts are disabled, but we will call the profiling routines
159 * directly to determine their overheads.
160 */
161 p->state = GMON_PROF_HIRES;
162
163 startguprof(p);
164 nullfunc_loop_profiled();
165
166 startguprof(p);
167 for (i = 0; i < CALIB_SCALE; i++)
168#if defined(__i386__) && __GNUC__ >= 2
169 __asm("pushl %0; call __mcount; popl %%ecx"
170 :
171 : "i" (profil)
172 : "ax", "bx", "cx", "dx", "memory");
173#else
174#error
175#endif
176 mcount_overhead = KCOUNT(p, PC_TO_I(p, profil));
177
178 startguprof(p);
179 for (i = 0; i < CALIB_SCALE; i++)
180#if defined(__i386__) && __GNUC__ >= 2
181 __asm("call " __XSTRING(HIDENAME(mexitcount)) "; 1:"
182 : : : "ax", "bx", "cx", "dx", "memory");
183 __asm("movl $1b,%0" : "=rm" (tmp_addr));
184#else
185#error
186#endif
187 mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr));
188
189 p->state = GMON_PROF_OFF;
190 stopguprof(p);
191
193 restore_intr(intrstate);
192 critical_exit(savecrit);
194
195 nullfunc_loop_profiled_time = 0;
196 for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled;
197 tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end;
198 tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER))
199 nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr));
200#define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE)
201#define c2n(count, freq) ((int)((count) * 1000000000LL / freq))
202 printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n",
203 CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)),
204 CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)),
205 CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)),
206 CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)),
207 CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate)));
208 cputime_overhead -= empty_loop_time;
209 mcount_overhead -= empty_loop_time;
210 mexitcount_overhead -= empty_loop_time;
211
212 /*-
213 * Profiling overheads are determined by the times between the
214 * following events:
215 * MC1: mcount() is called
216 * MC2: cputime() (called from mcount()) latches the timer
217 * MC3: mcount() completes
218 * ME1: mexitcount() is called
219 * ME2: cputime() (called from mexitcount()) latches the timer
220 * ME3: mexitcount() completes.
221 * The times between the events vary slightly depending on instruction
222 * combination and cache misses, etc. Attempt to determine the
223 * minimum times. These can be subtracted from the profiling times
224 * without much risk of reducing the profiling times below what they
225 * would be when profiling is not configured. Abbreviate:
226 * ab = minimum time between MC1 and MC3
227 * a = minumum time between MC1 and MC2
228 * b = minimum time between MC2 and MC3
229 * cd = minimum time between ME1 and ME3
230 * c = minimum time between ME1 and ME2
231 * d = minimum time between ME2 and ME3.
232 * These satisfy the relations:
233 * ab <= mcount_overhead (just measured)
234 * a + b <= ab
235 * cd <= mexitcount_overhead (just measured)
236 * c + d <= cd
237 * a + d <= nullfunc_loop_profiled_time (just measured)
238 * a >= 0, b >= 0, c >= 0, d >= 0.
239 * Assume that ab and cd are equal to the minimums.
240 */
241 p->cputime_overhead = CALIB_DOSCALE(cputime_overhead);
242 p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead);
243 p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead
244 - cputime_overhead);
245 nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time;
246 p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead
247 - nullfunc_loop_overhead)
248 / 4);
249 p->mexitcount_pre_overhead = p->mexitcount_overhead
250 + p->cputime_overhead
251 - p->mexitcount_post_overhead;
252 p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead)
253 - p->mexitcount_post_overhead;
254 p->mcount_post_overhead = p->mcount_overhead
255 + p->cputime_overhead
256 - p->mcount_pre_overhead;
257 printf(
258"Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n",
259 c2n(p->cputime_overhead, p->profrate),
260 c2n(p->mcount_overhead, p->profrate),
261 c2n(p->mcount_pre_overhead, p->profrate),
262 c2n(p->mcount_post_overhead, p->profrate),
263 c2n(p->cputime_overhead, p->profrate),
264 c2n(p->mexitcount_overhead, p->profrate),
265 c2n(p->mexitcount_pre_overhead, p->profrate),
266 c2n(p->mexitcount_post_overhead, p->profrate));
267 printf(
268"Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n",
269 p->cputime_overhead, p->mcount_overhead,
270 p->mcount_pre_overhead, p->mcount_post_overhead,
271 p->cputime_overhead, p->mexitcount_overhead,
272 p->mexitcount_pre_overhead, p->mexitcount_post_overhead);
273#endif /* GUPROF */
274}
275
276/*
277 * Return kernel profiling information.
278 */
279static int
280sysctl_kern_prof(SYSCTL_HANDLER_ARGS)
281{
282 int *name = (int *) arg1;
283 u_int namelen = arg2;
284 struct gmonparam *gp = &_gmonparam;
285 int error;
286 int state;
287
288 /* all sysctl names at this level are terminal */
289 if (namelen != 1)
290 return (ENOTDIR); /* overloaded */
291
292 switch (name[0]) {
293 case GPROF_STATE:
294 state = gp->state;
295 error = sysctl_handle_int(oidp, &state, 0, req);
296 if (error)
297 return (error);
298 if (!req->newptr)
299 return (0);
300 if (state == GMON_PROF_OFF) {
301 gp->state = state;
302 stopprofclock(&proc0);
303 stopguprof(gp);
304 } else if (state == GMON_PROF_ON) {
305 gp->state = GMON_PROF_OFF;
306 stopguprof(gp);
307 gp->profrate = profhz;
308 startprofclock(&proc0);
309 gp->state = state;
310#ifdef GUPROF
311 } else if (state == GMON_PROF_HIRES) {
312 gp->state = GMON_PROF_OFF;
313 stopprofclock(&proc0);
314 startguprof(gp);
315 gp->state = state;
316#endif
317 } else if (state != gp->state)
318 return (EINVAL);
319 return (0);
320 case GPROF_COUNT:
321 return (sysctl_handle_opaque(oidp,
322 gp->kcount, gp->kcountsize, req));
323 case GPROF_FROMS:
324 return (sysctl_handle_opaque(oidp,
325 gp->froms, gp->fromssize, req));
326 case GPROF_TOS:
327 return (sysctl_handle_opaque(oidp,
328 gp->tos, gp->tossize, req));
329 case GPROF_GMONPARAM:
330 return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req));
331 default:
332 return (EOPNOTSUPP);
333 }
334 /* NOTREACHED */
335}
336
337SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, "");
338#endif /* GPROF */
339
340/*
341 * Profiling system call.
342 *
343 * The scale factor is a fixed point number with 16 bits of fraction, so that
344 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling.
345 */
346#ifndef _SYS_SYSPROTO_H_
347struct profil_args {
348 caddr_t samples;
349 size_t size;
350 size_t offset;
351 u_int scale;
352};
353#endif
354/* ARGSUSED */
355int
356profil(p, uap)
357 struct proc *p;
358 register struct profil_args *uap;
359{
360 register struct uprof *upp;
361 int s;
362
363 if (uap->scale > (1 << 16))
364 return (EINVAL);
365 if (uap->scale == 0) {
366 stopprofclock(p);
367 return (0);
368 }
369 upp = &p->p_stats->p_prof;
370
371 /* Block profile interrupts while changing state. */
372 s = splstatclock();
373 upp->pr_off = uap->offset;
374 upp->pr_scale = uap->scale;
375 upp->pr_base = uap->samples;
376 upp->pr_size = uap->size;
377 startprofclock(p);
378 splx(s);
379
380 return (0);
381}
382
383/*
384 * Scale is a fixed-point number with the binary point 16 bits
385 * into the value, and is <= 1.0. pc is at most 32 bits, so the
386 * intermediate result is at most 48 bits.
387 */
388#define PC_TO_INDEX(pc, prof) \
389 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
390 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
391
392/*
393 * Collect user-level profiling statistics; called on a profiling tick,
394 * when a process is running in user-mode. This routine may be called
395 * from an interrupt context. We try to update the user profiling buffers
396 * cheaply with fuswintr() and suswintr(). If that fails, we revert to
397 * an AST that will vector us to trap() with a context in which copyin
398 * and copyout will work. Trap will then call addupc_task().
399 *
400 * Note that we may (rarely) not get around to the AST soon enough, and
401 * lose profile ticks when the next tick overwrites this one, but in this
402 * case the system is overloaded and the profile is probably already
403 * inaccurate.
404 */
405void
406addupc_intr(p, pc, ticks)
407 register struct proc *p;
408 register uintptr_t pc;
409 u_int ticks;
410{
411 register struct uprof *prof;
412 register caddr_t addr;
413 register u_int i;
414 register int v;
415
416 if (ticks == 0)
417 return;
418 prof = &p->p_stats->p_prof;
419 if (pc < prof->pr_off ||
420 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
421 return; /* out of range; ignore */
422
423 addr = prof->pr_base + i;
424 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) {
425 prof->pr_addr = pc;
426 prof->pr_ticks = ticks;
427 need_proftick(p);
428 }
429}
430
431/*
432 * Much like before, but we can afford to take faults here. If the
433 * update fails, we simply turn off profiling.
434 */
435void
436addupc_task(p, pc, ticks)
437 register struct proc *p;
438 register uintptr_t pc;
439 u_int ticks;
440{
441 register struct uprof *prof;
442 register caddr_t addr;
443 register u_int i;
444 u_short v;
445
446 /* Testing PS_PROFIL may be unnecessary, but is certainly safe. */
447 mtx_lock_spin(&sched_lock);
448 if ((p->p_sflag & PS_PROFIL) == 0 || ticks == 0) {
449 mtx_unlock_spin(&sched_lock);
450 return;
451 }
452 mtx_unlock_spin(&sched_lock);
453
454 prof = &p->p_stats->p_prof;
455 if (pc < prof->pr_off ||
456 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
457 return;
458
459 addr = prof->pr_base + i;
460 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) {
461 v += ticks;
462 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0)
463 return;
464 }
465 stopprofclock(p);
466}
193
194 nullfunc_loop_profiled_time = 0;
195 for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled;
196 tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end;
197 tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER))
198 nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr));
199#define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE)
200#define c2n(count, freq) ((int)((count) * 1000000000LL / freq))
201 printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n",
202 CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)),
203 CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)),
204 CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)),
205 CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)),
206 CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate)));
207 cputime_overhead -= empty_loop_time;
208 mcount_overhead -= empty_loop_time;
209 mexitcount_overhead -= empty_loop_time;
210
211 /*-
212 * Profiling overheads are determined by the times between the
213 * following events:
214 * MC1: mcount() is called
215 * MC2: cputime() (called from mcount()) latches the timer
216 * MC3: mcount() completes
217 * ME1: mexitcount() is called
218 * ME2: cputime() (called from mexitcount()) latches the timer
219 * ME3: mexitcount() completes.
220 * The times between the events vary slightly depending on instruction
221 * combination and cache misses, etc. Attempt to determine the
222 * minimum times. These can be subtracted from the profiling times
223 * without much risk of reducing the profiling times below what they
224 * would be when profiling is not configured. Abbreviate:
225 * ab = minimum time between MC1 and MC3
226 * a = minumum time between MC1 and MC2
227 * b = minimum time between MC2 and MC3
228 * cd = minimum time between ME1 and ME3
229 * c = minimum time between ME1 and ME2
230 * d = minimum time between ME2 and ME3.
231 * These satisfy the relations:
232 * ab <= mcount_overhead (just measured)
233 * a + b <= ab
234 * cd <= mexitcount_overhead (just measured)
235 * c + d <= cd
236 * a + d <= nullfunc_loop_profiled_time (just measured)
237 * a >= 0, b >= 0, c >= 0, d >= 0.
238 * Assume that ab and cd are equal to the minimums.
239 */
240 p->cputime_overhead = CALIB_DOSCALE(cputime_overhead);
241 p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead);
242 p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead
243 - cputime_overhead);
244 nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time;
245 p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead
246 - nullfunc_loop_overhead)
247 / 4);
248 p->mexitcount_pre_overhead = p->mexitcount_overhead
249 + p->cputime_overhead
250 - p->mexitcount_post_overhead;
251 p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead)
252 - p->mexitcount_post_overhead;
253 p->mcount_post_overhead = p->mcount_overhead
254 + p->cputime_overhead
255 - p->mcount_pre_overhead;
256 printf(
257"Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n",
258 c2n(p->cputime_overhead, p->profrate),
259 c2n(p->mcount_overhead, p->profrate),
260 c2n(p->mcount_pre_overhead, p->profrate),
261 c2n(p->mcount_post_overhead, p->profrate),
262 c2n(p->cputime_overhead, p->profrate),
263 c2n(p->mexitcount_overhead, p->profrate),
264 c2n(p->mexitcount_pre_overhead, p->profrate),
265 c2n(p->mexitcount_post_overhead, p->profrate));
266 printf(
267"Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n",
268 p->cputime_overhead, p->mcount_overhead,
269 p->mcount_pre_overhead, p->mcount_post_overhead,
270 p->cputime_overhead, p->mexitcount_overhead,
271 p->mexitcount_pre_overhead, p->mexitcount_post_overhead);
272#endif /* GUPROF */
273}
274
275/*
276 * Return kernel profiling information.
277 */
278static int
279sysctl_kern_prof(SYSCTL_HANDLER_ARGS)
280{
281 int *name = (int *) arg1;
282 u_int namelen = arg2;
283 struct gmonparam *gp = &_gmonparam;
284 int error;
285 int state;
286
287 /* all sysctl names at this level are terminal */
288 if (namelen != 1)
289 return (ENOTDIR); /* overloaded */
290
291 switch (name[0]) {
292 case GPROF_STATE:
293 state = gp->state;
294 error = sysctl_handle_int(oidp, &state, 0, req);
295 if (error)
296 return (error);
297 if (!req->newptr)
298 return (0);
299 if (state == GMON_PROF_OFF) {
300 gp->state = state;
301 stopprofclock(&proc0);
302 stopguprof(gp);
303 } else if (state == GMON_PROF_ON) {
304 gp->state = GMON_PROF_OFF;
305 stopguprof(gp);
306 gp->profrate = profhz;
307 startprofclock(&proc0);
308 gp->state = state;
309#ifdef GUPROF
310 } else if (state == GMON_PROF_HIRES) {
311 gp->state = GMON_PROF_OFF;
312 stopprofclock(&proc0);
313 startguprof(gp);
314 gp->state = state;
315#endif
316 } else if (state != gp->state)
317 return (EINVAL);
318 return (0);
319 case GPROF_COUNT:
320 return (sysctl_handle_opaque(oidp,
321 gp->kcount, gp->kcountsize, req));
322 case GPROF_FROMS:
323 return (sysctl_handle_opaque(oidp,
324 gp->froms, gp->fromssize, req));
325 case GPROF_TOS:
326 return (sysctl_handle_opaque(oidp,
327 gp->tos, gp->tossize, req));
328 case GPROF_GMONPARAM:
329 return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req));
330 default:
331 return (EOPNOTSUPP);
332 }
333 /* NOTREACHED */
334}
335
336SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, "");
337#endif /* GPROF */
338
339/*
340 * Profiling system call.
341 *
342 * The scale factor is a fixed point number with 16 bits of fraction, so that
343 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling.
344 */
345#ifndef _SYS_SYSPROTO_H_
346struct profil_args {
347 caddr_t samples;
348 size_t size;
349 size_t offset;
350 u_int scale;
351};
352#endif
353/* ARGSUSED */
354int
355profil(p, uap)
356 struct proc *p;
357 register struct profil_args *uap;
358{
359 register struct uprof *upp;
360 int s;
361
362 if (uap->scale > (1 << 16))
363 return (EINVAL);
364 if (uap->scale == 0) {
365 stopprofclock(p);
366 return (0);
367 }
368 upp = &p->p_stats->p_prof;
369
370 /* Block profile interrupts while changing state. */
371 s = splstatclock();
372 upp->pr_off = uap->offset;
373 upp->pr_scale = uap->scale;
374 upp->pr_base = uap->samples;
375 upp->pr_size = uap->size;
376 startprofclock(p);
377 splx(s);
378
379 return (0);
380}
381
382/*
383 * Scale is a fixed-point number with the binary point 16 bits
384 * into the value, and is <= 1.0. pc is at most 32 bits, so the
385 * intermediate result is at most 48 bits.
386 */
387#define PC_TO_INDEX(pc, prof) \
388 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
389 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
390
391/*
392 * Collect user-level profiling statistics; called on a profiling tick,
393 * when a process is running in user-mode. This routine may be called
394 * from an interrupt context. We try to update the user profiling buffers
395 * cheaply with fuswintr() and suswintr(). If that fails, we revert to
396 * an AST that will vector us to trap() with a context in which copyin
397 * and copyout will work. Trap will then call addupc_task().
398 *
399 * Note that we may (rarely) not get around to the AST soon enough, and
400 * lose profile ticks when the next tick overwrites this one, but in this
401 * case the system is overloaded and the profile is probably already
402 * inaccurate.
403 */
404void
405addupc_intr(p, pc, ticks)
406 register struct proc *p;
407 register uintptr_t pc;
408 u_int ticks;
409{
410 register struct uprof *prof;
411 register caddr_t addr;
412 register u_int i;
413 register int v;
414
415 if (ticks == 0)
416 return;
417 prof = &p->p_stats->p_prof;
418 if (pc < prof->pr_off ||
419 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
420 return; /* out of range; ignore */
421
422 addr = prof->pr_base + i;
423 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) {
424 prof->pr_addr = pc;
425 prof->pr_ticks = ticks;
426 need_proftick(p);
427 }
428}
429
430/*
431 * Much like before, but we can afford to take faults here. If the
432 * update fails, we simply turn off profiling.
433 */
434void
435addupc_task(p, pc, ticks)
436 register struct proc *p;
437 register uintptr_t pc;
438 u_int ticks;
439{
440 register struct uprof *prof;
441 register caddr_t addr;
442 register u_int i;
443 u_short v;
444
445 /* Testing PS_PROFIL may be unnecessary, but is certainly safe. */
446 mtx_lock_spin(&sched_lock);
447 if ((p->p_sflag & PS_PROFIL) == 0 || ticks == 0) {
448 mtx_unlock_spin(&sched_lock);
449 return;
450 }
451 mtx_unlock_spin(&sched_lock);
452
453 prof = &p->p_stats->p_prof;
454 if (pc < prof->pr_off ||
455 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
456 return;
457
458 addr = prof->pr_base + i;
459 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) {
460 v += ticks;
461 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0)
462 return;
463 }
464 stopprofclock(p);
465}