subr_prof.c revision 1.37
1/* $NetBSD: subr_prof.c,v 1.37 2006/12/13 16:51:27 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 1.37 2006/12/13 16:51:27 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/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 53MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer"); 54 55/* 56 * Froms is actually a bunch of unsigned shorts indexing tos 57 */ 58struct gmonparam _gmonparam = { .state = GMON_PROF_OFF }; 59 60/* Actual start of the kernel text segment. */ 61extern char kernel_text[]; 62 63extern char etext[]; 64 65 66void 67kmstartup(void) 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 */ 112static int 113sysctl_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 159SYSCTL_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 */ 217int 218sys_profil(struct lwp *l, void *v, register_t *retval) 219{ 220 struct sys_profil_args /* { 221 syscallarg(caddr_t) samples; 222 syscallarg(u_int) size; 223 syscallarg(u_int) offset; 224 syscallarg(u_int) scale; 225 } */ *uap = v; 226 struct proc *p = l->l_proc; 227 struct uprof *upp; 228 int s; 229 230 if (SCARG(uap, scale) > (1 << 16)) 231 return (EINVAL); 232 if (SCARG(uap, scale) == 0) { 233 stopprofclock(p); 234 return (0); 235 } 236 upp = &p->p_stats->p_prof; 237 238 /* Block profile interrupts while changing state. */ 239 s = splstatclock(); 240 upp->pr_off = SCARG(uap, offset); 241 upp->pr_scale = SCARG(uap, scale); 242 upp->pr_base = SCARG(uap, samples); 243 upp->pr_size = SCARG(uap, size); 244 startprofclock(p); 245 splx(s); 246 247 return (0); 248} 249 250/* 251 * Scale is a fixed-point number with the binary point 16 bits 252 * into the value, and is <= 1.0. pc is at most 32 bits, so the 253 * intermediate result is at most 48 bits. 254 */ 255#define PC_TO_INDEX(pc, prof) \ 256 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 257 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 258 259/* 260 * Collect user-level profiling statistics; called on a profiling tick, 261 * when a process is running in user-mode. This routine may be called 262 * from an interrupt context. We try to update the user profiling buffers 263 * cheaply with fuswintr() and suswintr(). If that fails, we revert to 264 * an AST that will vector us to trap() with a context in which copyin 265 * and copyout will work. Trap will then call addupc_task(). 266 * 267 * Note that we may (rarely) not get around to the AST soon enough, and 268 * lose profile ticks when the next tick overwrites this one, but in this 269 * case the system is overloaded and the profile is probably already 270 * inaccurate. 271 */ 272void 273addupc_intr(struct proc *p, u_long pc) 274{ 275 struct uprof *prof; 276 caddr_t addr; 277 u_int i; 278 int v; 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 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + 1) == -1) { 287 prof->pr_addr = pc; 288 prof->pr_ticks++; 289 need_proftick(p); 290 } 291} 292 293/* 294 * Much like before, but we can afford to take faults here. If the 295 * update fails, we simply turn off profiling. 296 */ 297void 298addupc_task(struct proc *p, u_long pc, u_int ticks) 299{ 300 struct uprof *prof; 301 caddr_t addr; 302 u_int i; 303 u_short v; 304 305 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */ 306 if ((p->p_flag & P_PROFIL) == 0 || ticks == 0) 307 return; 308 309 prof = &p->p_stats->p_prof; 310 if (pc < prof->pr_off || 311 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 312 return; 313 314 addr = prof->pr_base + i; 315 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) { 316 v += ticks; 317 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0) 318 return; 319 } 320 stopprofclock(p); 321} 322