FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_prof.c
1 /* $NetBSD: subr_prof.c,v 1.31 2004/04/08 06:20:30 atatat Exp $ */
2
3 /*-
4 * Copyright (c) 1982, 1986, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)subr_prof.c 8.4 (Berkeley) 2/14/95
32 */
33
34 #include <sys/cdefs.h>
35 __KERNEL_RCSID(0, "$NetBSD: subr_prof.c,v 1.31 2004/04/08 06:20:30 atatat Exp $");
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/kernel.h>
40 #include <sys/proc.h>
41 #include <sys/user.h>
42 #include <sys/mount.h>
43 #include <sys/sa.h>
44 #include <sys/syscallargs.h>
45 #include <sys/sysctl.h>
46
47 #include <machine/cpu.h>
48
49 #ifdef GPROF
50 #include <sys/malloc.h>
51 #include <sys/gmon.h>
52
53 MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer");
54
55 /*
56 * Froms is actually a bunch of unsigned shorts indexing tos
57 */
58 struct gmonparam _gmonparam = { GMON_PROF_OFF };
59
60 /* Actual start of the kernel text segment. */
61 extern char kernel_text[];
62
63 extern char etext[];
64
65
66 void
67 kmstartup()
68 {
69 char *cp;
70 struct gmonparam *p = &_gmonparam;
71 /*
72 * Round lowpc and highpc to multiples of the density we're using
73 * so the rest of the scaling (here and in gprof) stays in ints.
74 */
75 p->lowpc = ROUNDDOWN(((u_long)kernel_text),
76 HISTFRACTION * sizeof(HISTCOUNTER));
77 p->highpc = ROUNDUP((u_long)etext,
78 HISTFRACTION * sizeof(HISTCOUNTER));
79 p->textsize = p->highpc - p->lowpc;
80 printf("Profiling kernel, textsize=%ld [%lx..%lx]\n",
81 p->textsize, p->lowpc, p->highpc);
82 p->kcountsize = p->textsize / HISTFRACTION;
83 p->hashfraction = HASHFRACTION;
84 p->fromssize = p->textsize / HASHFRACTION;
85 p->tolimit = p->textsize * ARCDENSITY / 100;
86 if (p->tolimit < MINARCS)
87 p->tolimit = MINARCS;
88 else if (p->tolimit > MAXARCS)
89 p->tolimit = MAXARCS;
90 p->tossize = p->tolimit * sizeof(struct tostruct);
91 cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize,
92 M_GPROF, M_NOWAIT);
93 if (cp == 0) {
94 printf("No memory for profiling.\n");
95 return;
96 }
97 memset(cp, 0, p->kcountsize + p->tossize + p->fromssize);
98 p->tos = (struct tostruct *)cp;
99 cp += p->tossize;
100 p->kcount = (u_short *)cp;
101 cp += p->kcountsize;
102 p->froms = (u_short *)cp;
103 }
104
105 /*
106 * Return kernel profiling information.
107 */
108 /*
109 * sysctl helper routine for kern.profiling subtree. enables/disables
110 * kernel profiling and gives out copies of the profiling data.
111 */
112 static int
113 sysctl_kern_profiling(SYSCTLFN_ARGS)
114 {
115 struct gmonparam *gp = &_gmonparam;
116 int error;
117 struct sysctlnode node;
118
119 node = *rnode;
120
121 switch (node.sysctl_num) {
122 case GPROF_STATE:
123 node.sysctl_data = &gp->state;
124 break;
125 case GPROF_COUNT:
126 node.sysctl_data = gp->kcount;
127 node.sysctl_size = gp->kcountsize;
128 break;
129 case GPROF_FROMS:
130 node.sysctl_data = gp->froms;
131 node.sysctl_size = gp->fromssize;
132 break;
133 case GPROF_TOS:
134 node.sysctl_data = gp->tos;
135 node.sysctl_size = gp->tossize;
136 break;
137 case GPROF_GMONPARAM:
138 node.sysctl_data = gp;
139 node.sysctl_size = sizeof(*gp);
140 break;
141 default:
142 return (EOPNOTSUPP);
143 }
144
145 error = sysctl_lookup(SYSCTLFN_CALL(&node));
146 if (error || newp == NULL)
147 return (error);
148
149 if (node.sysctl_num == GPROF_STATE) {
150 if (gp->state == GMON_PROF_OFF)
151 stopprofclock(&proc0);
152 else
153 startprofclock(&proc0);
154 }
155
156 return (0);
157 }
158
159 SYSCTL_SETUP(sysctl_kern_gprof_setup, "sysctl kern.profiling subtree setup")
160 {
161
162 sysctl_createv(clog, 0, NULL, NULL,
163 CTLFLAG_PERMANENT,
164 CTLTYPE_NODE, "kern", NULL,
165 NULL, 0, NULL, 0,
166 CTL_KERN, CTL_EOL);
167 sysctl_createv(clog, 0, NULL, NULL,
168 CTLFLAG_PERMANENT,
169 CTLTYPE_NODE, "profiling",
170 SYSCTL_DESCR("Profiling information (available)"),
171 NULL, 0, NULL, 0,
172 CTL_KERN, KERN_PROF, CTL_EOL);
173
174 sysctl_createv(clog, 0, NULL, NULL,
175 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
176 CTLTYPE_INT, "state",
177 SYSCTL_DESCR("Profiling state"),
178 sysctl_kern_profiling, 0, NULL, 0,
179 CTL_KERN, KERN_PROF, GPROF_STATE, CTL_EOL);
180 sysctl_createv(clog, 0, NULL, NULL,
181 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
182 CTLTYPE_STRUCT, "count",
183 SYSCTL_DESCR("Array of statistical program counters"),
184 sysctl_kern_profiling, 0, NULL, 0,
185 CTL_KERN, KERN_PROF, GPROF_COUNT, CTL_EOL);
186 sysctl_createv(clog, 0, NULL, NULL,
187 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
188 CTLTYPE_STRUCT, "froms",
189 SYSCTL_DESCR("Array indexed by program counter of "
190 "call-from points"),
191 sysctl_kern_profiling, 0, NULL, 0,
192 CTL_KERN, KERN_PROF, GPROF_FROMS, CTL_EOL);
193 sysctl_createv(clog, 0, NULL, NULL,
194 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
195 CTLTYPE_STRUCT, "tos",
196 SYSCTL_DESCR("Array of structures describing "
197 "destination of calls and their counts"),
198 sysctl_kern_profiling, 0, NULL, 0,
199 CTL_KERN, KERN_PROF, GPROF_TOS, CTL_EOL);
200 sysctl_createv(clog, 0, NULL, NULL,
201 CTLFLAG_PERMANENT,
202 CTLTYPE_STRUCT, "gmonparam",
203 SYSCTL_DESCR("Structure giving the sizes of the above "
204 "arrays"),
205 sysctl_kern_profiling, 0, NULL, 0,
206 CTL_KERN, KERN_PROF, GPROF_GMONPARAM, CTL_EOL);
207 }
208 #endif /* GPROF */
209
210 /*
211 * Profiling system call.
212 *
213 * The scale factor is a fixed point number with 16 bits of fraction, so that
214 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling.
215 */
216 /* ARGSUSED */
217 int
218 sys_profil(l, v, retval)
219 struct lwp *l;
220 void *v;
221 register_t *retval;
222 {
223 struct sys_profil_args /* {
224 syscallarg(caddr_t) samples;
225 syscallarg(u_int) size;
226 syscallarg(u_int) offset;
227 syscallarg(u_int) scale;
228 } */ *uap = v;
229 struct proc *p = l->l_proc;
230 struct uprof *upp;
231 int s;
232
233 if (SCARG(uap, scale) > (1 << 16))
234 return (EINVAL);
235 if (SCARG(uap, scale) == 0) {
236 stopprofclock(p);
237 return (0);
238 }
239 upp = &p->p_stats->p_prof;
240
241 /* Block profile interrupts while changing state. */
242 s = splstatclock();
243 upp->pr_off = SCARG(uap, offset);
244 upp->pr_scale = SCARG(uap, scale);
245 upp->pr_base = SCARG(uap, samples);
246 upp->pr_size = SCARG(uap, size);
247 startprofclock(p);
248 splx(s);
249
250 return (0);
251 }
252
253 /*
254 * Scale is a fixed-point number with the binary point 16 bits
255 * into the value, and is <= 1.0. pc is at most 32 bits, so the
256 * intermediate result is at most 48 bits.
257 */
258 #define PC_TO_INDEX(pc, prof) \
259 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
260 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
261
262 /*
263 * Collect user-level profiling statistics; called on a profiling tick,
264 * when a process is running in user-mode. This routine may be called
265 * from an interrupt context. We try to update the user profiling buffers
266 * cheaply with fuswintr() and suswintr(). If that fails, we revert to
267 * an AST that will vector us to trap() with a context in which copyin
268 * and copyout will work. Trap will then call addupc_task().
269 *
270 * Note that we may (rarely) not get around to the AST soon enough, and
271 * lose profile ticks when the next tick overwrites this one, but in this
272 * case the system is overloaded and the profile is probably already
273 * inaccurate.
274 */
275 void
276 addupc_intr(p, pc)
277 struct proc *p;
278 u_long pc;
279 {
280 struct uprof *prof;
281 caddr_t addr;
282 u_int i;
283 int v;
284
285 prof = &p->p_stats->p_prof;
286 if (pc < prof->pr_off ||
287 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
288 return; /* out of range; ignore */
289
290 addr = prof->pr_base + i;
291 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + 1) == -1) {
292 prof->pr_addr = pc;
293 prof->pr_ticks++;
294 need_proftick(p);
295 }
296 }
297
298 /*
299 * Much like before, but we can afford to take faults here. If the
300 * update fails, we simply turn off profiling.
301 */
302 void
303 addupc_task(p, pc, ticks)
304 struct proc *p;
305 u_long pc;
306 u_int ticks;
307 {
308 struct uprof *prof;
309 caddr_t addr;
310 u_int i;
311 u_short v;
312
313 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */
314 if ((p->p_flag & P_PROFIL) == 0 || ticks == 0)
315 return;
316
317 prof = &p->p_stats->p_prof;
318 if (pc < prof->pr_off ||
319 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
320 return;
321
322 addr = prof->pr_base + i;
323 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) {
324 v += ticks;
325 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0)
326 return;
327 }
328 stopprofclock(p);
329 }
Cache object: 3ba490f8ec2723681cb1ea635877afe3
|