| 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 | |