Disallow writes to filesystems mounted read-only via NULLFS. In this case
[dragonfly.git] / sys / kern / subr_prof.c
CommitLineData
984263bc
MD
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: src/sys/kern/subr_prof.c,v 1.32.2.2 2000/08/03 00:09:32 ps Exp $
753fd850 35 * $DragonFly: src/sys/kern/subr_prof.c,v 1.12 2006/06/05 07:26:10 dillon Exp $
984263bc
MD
36 */
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/sysproto.h>
41#include <sys/kernel.h>
42#include <sys/proc.h>
43#include <sys/resourcevar.h>
44#include <sys/sysctl.h>
e43a034f 45#include <sys/thread2.h>
984263bc
MD
46
47#include <machine/ipl.h>
48#include <machine/cpu.h>
49
50#ifdef GPROF
51#include <sys/malloc.h>
52#include <sys/gmon.h>
53#undef MCOUNT
54
55static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer");
56
402ed7e1 57static void kmstartup (void *);
984263bc
MD
58SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL)
59
60struct gmonparam _gmonparam = { GMON_PROF_OFF };
61
62#ifdef GUPROF
63#include <machine/asmacros.h>
64
65void
66nullfunc_loop_profiled()
67{
68 int i;
69
70 for (i = 0; i < CALIB_SCALE; i++)
71 nullfunc_profiled();
72}
73
74#define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */
75
76void
77nullfunc_profiled()
78{
79}
80#endif /* GUPROF */
81
82static void
493c516a 83kmstartup(void *dummy)
984263bc
MD
84{
85 char *cp;
86 struct gmonparam *p = &_gmonparam;
87#ifdef GUPROF
88 int cputime_overhead;
89 int empty_loop_time;
90 int i;
91 int mcount_overhead;
92 int mexitcount_overhead;
93 int nullfunc_loop_overhead;
94 int nullfunc_loop_profiled_time;
95 uintfptr_t tmp_addr;
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);
118 if (cp == 0) {
119 printf("No memory for profiling.\n");
120 return;
121 }
122 bzero(cp, p->kcountsize + p->tossize + p->fromssize);
123 p->tos = (struct tostruct *)cp;
124 cp += p->tossize;
125 p->kcount = (HISTCOUNTER *)cp;
126 cp += p->kcountsize;
127 p->froms = (u_short *)cp;
128
129#ifdef GUPROF
130 /* Initialize pointers to overhead counters. */
131 p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime));
132 p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount));
133 p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount));
134
135 /*
136 * Disable interrupts to avoid interference while we calibrate
137 * things.
138 */
eac48440 139 cpu_disable_intr();
984263bc
MD
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
eac48440 193 cpu_enable_intr();
984263bc
MD
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 */
984263bc
MD
346/* ARGSUSED */
347int
753fd850 348sys_profil(struct profil_args *uap)
984263bc 349{
41c20dac
MD
350 struct proc *p = curproc;
351 struct uprof *upp;
984263bc
MD
352
353 if (uap->scale > (1 << 16))
354 return (EINVAL);
355 if (uap->scale == 0) {
356 stopprofclock(p);
357 return (0);
358 }
93328593 359 upp = &p->p_prof;
984263bc
MD
360
361 /* Block profile interrupts while changing state. */
e43a034f 362 crit_enter();
984263bc
MD
363 upp->pr_off = uap->offset;
364 upp->pr_scale = uap->scale;
365 upp->pr_base = uap->samples;
366 upp->pr_size = uap->size;
367 startprofclock(p);
e43a034f 368 crit_exit();
984263bc
MD
369
370 return (0);
371}
372
373/*
374 * Scale is a fixed-point number with the binary point 16 bits
375 * into the value, and is <= 1.0. pc is at most 32 bits, so the
376 * intermediate result is at most 48 bits.
377 */
378#define PC_TO_INDEX(pc, prof) \
379 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
380 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
381
382/*
383 * Collect user-level profiling statistics; called on a profiling tick,
384 * when a process is running in user-mode. This routine may be called
385 * from an interrupt context. We try to update the user profiling buffers
386 * cheaply with fuswintr() and suswintr(). If that fails, we revert to
387 * an AST that will vector us to trap() with a context in which copyin
388 * and copyout will work. Trap will then call addupc_task().
389 *
390 * Note that we may (rarely) not get around to the AST soon enough, and
391 * lose profile ticks when the next tick overwrites this one, but in this
392 * case the system is overloaded and the profile is probably already
393 * inaccurate.
394 */
395void
493c516a 396addupc_intr(struct proc *p, u_long pc, u_int ticks)
984263bc 397{
1fd87d54
RG
398 struct uprof *prof;
399 caddr_t addr;
400 u_int i;
401 int v;
984263bc
MD
402
403 if (ticks == 0)
404 return;
93328593 405 prof = &p->p_prof;
984263bc
MD
406 if (pc < prof->pr_off ||
407 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
408 return; /* out of range; ignore */
409
410 addr = prof->pr_base + i;
411 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) {
412 prof->pr_addr = pc;
413 prof->pr_ticks = ticks;
235957ed 414 need_proftick();
984263bc
MD
415 }
416}
417
418/*
419 * Much like before, but we can afford to take faults here. If the
420 * update fails, we simply turn off profiling.
421 */
422void
493c516a 423addupc_task(struct proc *p, u_long pc, u_int ticks)
984263bc 424{
1fd87d54
RG
425 struct uprof *prof;
426 caddr_t addr;
427 u_int i;
984263bc
MD
428 u_short v;
429
430 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */
431 if ((p->p_flag & P_PROFIL) == 0 || ticks == 0)
432 return;
433
93328593 434 prof = &p->p_prof;
984263bc
MD
435 if (pc < prof->pr_off ||
436 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
437 return;
438
439 addr = prof->pr_base + i;
440 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) {
441 v += ticks;
442 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0)
443 return;
444 }
445 stopprofclock(p);
446}