1 | /* $NetBSD: subr_prof.c,v 1.47 2014/07/10 21:13:52 christos 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 1.47 2014/07/10 21:13:52 christos 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/mount.h> |
42 | #include <sys/syscallargs.h> |
43 | #include <sys/sysctl.h> |
44 | |
45 | #include <sys/cpu.h> |
46 | |
47 | #ifdef GPROF |
48 | #include <sys/malloc.h> |
49 | #include <sys/gmon.h> |
50 | |
51 | MALLOC_DEFINE(M_GPROF, "gprof" , "kernel profiling buffer" ); |
52 | |
53 | /* |
54 | * Froms is actually a bunch of unsigned shorts indexing tos |
55 | */ |
56 | struct gmonparam _gmonparam = { .state = GMON_PROF_OFF }; |
57 | |
58 | /* Actual start of the kernel text segment. */ |
59 | extern char kernel_text[]; |
60 | |
61 | extern char etext[]; |
62 | |
63 | |
64 | void |
65 | kmstartup(void) |
66 | { |
67 | char *cp; |
68 | struct gmonparam *p = &_gmonparam; |
69 | /* |
70 | * Round lowpc and highpc to multiples of the density we're using |
71 | * so the rest of the scaling (here and in gprof) stays in ints. |
72 | */ |
73 | p->lowpc = rounddown(((u_long)kernel_text), |
74 | HISTFRACTION * sizeof(HISTCOUNTER)); |
75 | p->highpc = roundup((u_long)etext, |
76 | HISTFRACTION * sizeof(HISTCOUNTER)); |
77 | p->textsize = p->highpc - p->lowpc; |
78 | printf("Profiling kernel, textsize=%ld [%lx..%lx]\n" , |
79 | p->textsize, p->lowpc, p->highpc); |
80 | p->kcountsize = p->textsize / HISTFRACTION; |
81 | p->hashfraction = HASHFRACTION; |
82 | p->fromssize = p->textsize / HASHFRACTION; |
83 | p->tolimit = p->textsize * ARCDENSITY / 100; |
84 | if (p->tolimit < MINARCS) |
85 | p->tolimit = MINARCS; |
86 | else if (p->tolimit > MAXARCS) |
87 | p->tolimit = MAXARCS; |
88 | p->tossize = p->tolimit * sizeof(struct tostruct); |
89 | cp = malloc(p->kcountsize + p->fromssize + p->tossize, |
90 | M_GPROF, M_NOWAIT | M_ZERO); |
91 | if (cp == 0) { |
92 | printf("No memory for profiling.\n" ); |
93 | return; |
94 | } |
95 | p->tos = (struct tostruct *)cp; |
96 | cp += p->tossize; |
97 | p->kcount = (u_short *)cp; |
98 | cp += p->kcountsize; |
99 | p->froms = (u_short *)cp; |
100 | } |
101 | |
102 | /* |
103 | * Return kernel profiling information. |
104 | */ |
105 | /* |
106 | * sysctl helper routine for kern.profiling subtree. enables/disables |
107 | * kernel profiling and gives out copies of the profiling data. |
108 | */ |
109 | static int |
110 | sysctl_kern_profiling(SYSCTLFN_ARGS) |
111 | { |
112 | struct gmonparam *gp = &_gmonparam; |
113 | int error; |
114 | struct sysctlnode node; |
115 | |
116 | node = *rnode; |
117 | |
118 | switch (node.sysctl_num) { |
119 | case GPROF_STATE: |
120 | node.sysctl_data = &gp->state; |
121 | break; |
122 | case GPROF_COUNT: |
123 | node.sysctl_data = gp->kcount; |
124 | node.sysctl_size = gp->kcountsize; |
125 | break; |
126 | case GPROF_FROMS: |
127 | node.sysctl_data = gp->froms; |
128 | node.sysctl_size = gp->fromssize; |
129 | break; |
130 | case GPROF_TOS: |
131 | node.sysctl_data = gp->tos; |
132 | node.sysctl_size = gp->tossize; |
133 | break; |
134 | case GPROF_GMONPARAM: |
135 | node.sysctl_data = gp; |
136 | node.sysctl_size = sizeof(*gp); |
137 | break; |
138 | default: |
139 | return (EOPNOTSUPP); |
140 | } |
141 | |
142 | error = sysctl_lookup(SYSCTLFN_CALL(&node)); |
143 | if (error || newp == NULL) |
144 | return (error); |
145 | |
146 | if (node.sysctl_num == GPROF_STATE) { |
147 | mutex_spin_enter(&proc0.p_stmutex); |
148 | if (gp->state == GMON_PROF_OFF) |
149 | stopprofclock(&proc0); |
150 | else |
151 | startprofclock(&proc0); |
152 | mutex_spin_exit(&proc0.p_stmutex); |
153 | } |
154 | |
155 | return (0); |
156 | } |
157 | |
158 | SYSCTL_SETUP(sysctl_kern_gprof_setup, "sysctl kern.profiling subtree setup" ) |
159 | { |
160 | |
161 | sysctl_createv(clog, 0, NULL, NULL, |
162 | CTLFLAG_PERMANENT, |
163 | CTLTYPE_NODE, "profiling" , |
164 | SYSCTL_DESCR("Profiling information (available)" ), |
165 | NULL, 0, NULL, 0, |
166 | CTL_KERN, KERN_PROF, CTL_EOL); |
167 | |
168 | sysctl_createv(clog, 0, NULL, NULL, |
169 | CTLFLAG_PERMANENT|CTLFLAG_READWRITE, |
170 | CTLTYPE_INT, "state" , |
171 | SYSCTL_DESCR("Profiling state" ), |
172 | sysctl_kern_profiling, 0, NULL, 0, |
173 | CTL_KERN, KERN_PROF, GPROF_STATE, CTL_EOL); |
174 | sysctl_createv(clog, 0, NULL, NULL, |
175 | CTLFLAG_PERMANENT|CTLFLAG_READWRITE, |
176 | CTLTYPE_STRUCT, "count" , |
177 | SYSCTL_DESCR("Array of statistical program counters" ), |
178 | sysctl_kern_profiling, 0, NULL, 0, |
179 | CTL_KERN, KERN_PROF, GPROF_COUNT, CTL_EOL); |
180 | sysctl_createv(clog, 0, NULL, NULL, |
181 | CTLFLAG_PERMANENT|CTLFLAG_READWRITE, |
182 | CTLTYPE_STRUCT, "froms" , |
183 | SYSCTL_DESCR("Array indexed by program counter of " |
184 | "call-from points" ), |
185 | sysctl_kern_profiling, 0, NULL, 0, |
186 | CTL_KERN, KERN_PROF, GPROF_FROMS, CTL_EOL); |
187 | sysctl_createv(clog, 0, NULL, NULL, |
188 | CTLFLAG_PERMANENT|CTLFLAG_READWRITE, |
189 | CTLTYPE_STRUCT, "tos" , |
190 | SYSCTL_DESCR("Array of structures describing " |
191 | "destination of calls and their counts" ), |
192 | sysctl_kern_profiling, 0, NULL, 0, |
193 | CTL_KERN, KERN_PROF, GPROF_TOS, CTL_EOL); |
194 | sysctl_createv(clog, 0, NULL, NULL, |
195 | CTLFLAG_PERMANENT, |
196 | CTLTYPE_STRUCT, "gmonparam" , |
197 | SYSCTL_DESCR("Structure giving the sizes of the above " |
198 | "arrays" ), |
199 | sysctl_kern_profiling, 0, NULL, 0, |
200 | CTL_KERN, KERN_PROF, GPROF_GMONPARAM, CTL_EOL); |
201 | } |
202 | #endif /* GPROF */ |
203 | |
204 | /* |
205 | * Profiling system call. |
206 | * |
207 | * The scale factor is a fixed point number with 16 bits of fraction, so that |
208 | * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. |
209 | */ |
210 | /* ARGSUSED */ |
211 | int |
212 | sys_profil(struct lwp *l, const struct sys_profil_args *uap, register_t *retval) |
213 | { |
214 | /* { |
215 | syscallarg(char *) samples; |
216 | syscallarg(size_t) size; |
217 | syscallarg(u_long) offset; |
218 | syscallarg(u_int) scale; |
219 | } */ |
220 | struct proc *p = l->l_proc; |
221 | struct uprof *upp; |
222 | |
223 | if (SCARG(uap, scale) > (1 << 16)) |
224 | return (EINVAL); |
225 | if (SCARG(uap, scale) == 0) { |
226 | mutex_spin_enter(&p->p_stmutex); |
227 | stopprofclock(p); |
228 | mutex_spin_exit(&p->p_stmutex); |
229 | return (0); |
230 | } |
231 | upp = &p->p_stats->p_prof; |
232 | |
233 | /* Block profile interrupts while changing state. */ |
234 | mutex_spin_enter(&p->p_stmutex); |
235 | upp->pr_off = SCARG(uap, offset); |
236 | upp->pr_scale = SCARG(uap, scale); |
237 | upp->pr_base = SCARG(uap, samples); |
238 | upp->pr_size = SCARG(uap, size); |
239 | startprofclock(p); |
240 | mutex_spin_exit(&p->p_stmutex); |
241 | |
242 | return (0); |
243 | } |
244 | |
245 | /* |
246 | * Scale is a fixed-point number with the binary point 16 bits |
247 | * into the value, and is <= 1.0. pc is at most 32 bits, so the |
248 | * intermediate result is at most 48 bits. |
249 | */ |
250 | #define PC_TO_INDEX(pc, prof) \ |
251 | ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ |
252 | (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) |
253 | |
254 | /* |
255 | * Collect user-level profiling statistics; called on a profiling tick, |
256 | * when a process is running in user-mode. This routine may be called |
257 | * from an interrupt context. We try to update the user profiling buffers |
258 | * cheaply with fuswintr() and suswintr(). If that fails, we revert to |
259 | * an AST that will vector us to trap() with a context in which copyin |
260 | * and copyout will work. Trap will then call addupc_task(). |
261 | * |
262 | * Note that we may (rarely) not get around to the AST soon enough, and |
263 | * lose profile ticks when the next tick overwrites this one, but in this |
264 | * case the system is overloaded and the profile is probably already |
265 | * inaccurate. |
266 | */ |
267 | void |
268 | addupc_intr(struct lwp *l, u_long pc) |
269 | { |
270 | struct uprof *prof; |
271 | struct proc *p; |
272 | void *addr; |
273 | u_int i; |
274 | int v; |
275 | |
276 | p = l->l_proc; |
277 | |
278 | KASSERT(mutex_owned(&p->p_stmutex)); |
279 | |
280 | prof = &p->p_stats->p_prof; |
281 | if (pc < prof->pr_off || |
282 | (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) |
283 | return; /* out of range; ignore */ |
284 | |
285 | addr = prof->pr_base + i; |
286 | mutex_spin_exit(&p->p_stmutex); |
287 | if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + 1) == -1) { |
288 | /* XXXSMP */ |
289 | prof->pr_addr = pc; |
290 | prof->pr_ticks++; |
291 | cpu_need_proftick(l); |
292 | } |
293 | mutex_spin_enter(&p->p_stmutex); |
294 | } |
295 | |
296 | /* |
297 | * Much like before, but we can afford to take faults here. If the |
298 | * update fails, we simply turn off profiling. |
299 | */ |
300 | void |
301 | addupc_task(struct lwp *l, u_long pc, u_int ticks) |
302 | { |
303 | struct uprof *prof; |
304 | struct proc *p; |
305 | void *addr; |
306 | int error; |
307 | u_int i; |
308 | u_short v; |
309 | |
310 | p = l->l_proc; |
311 | |
312 | if (ticks == 0) |
313 | return; |
314 | |
315 | mutex_spin_enter(&p->p_stmutex); |
316 | prof = &p->p_stats->p_prof; |
317 | |
318 | /* Testing P_PROFIL may be unnecessary, but is certainly safe. */ |
319 | if ((p->p_stflag & PST_PROFIL) == 0 || pc < prof->pr_off || |
320 | (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { |
321 | mutex_spin_exit(&p->p_stmutex); |
322 | return; |
323 | } |
324 | |
325 | addr = prof->pr_base + i; |
326 | mutex_spin_exit(&p->p_stmutex); |
327 | if ((error = copyin(addr, (void *)&v, sizeof(v))) == 0) { |
328 | v += ticks; |
329 | error = copyout((void *)&v, addr, sizeof(v)); |
330 | } |
331 | if (error != 0) { |
332 | mutex_spin_enter(&p->p_stmutex); |
333 | stopprofclock(p); |
334 | mutex_spin_exit(&p->p_stmutex); |
335 | } |
336 | } |
337 | |