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 * $Id: subr_prof.c,v 1.16 1995/12/29 15:29:08 bde Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/sysproto.h> 40 #include <sys/kernel.h> 41 #include <sys/proc.h> 42 #include <sys/resourcevar.h> 43 #include <sys/sysctl.h> 44 45 #include <machine/cpu.h> 46 47 #ifdef GPROF 48 #include <sys/malloc.h> 49 #include <sys/gmon.h> 50 51 static void kmstartup __P((void *)); 52 SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL) 53 54 struct gmonparam _gmonparam = { GMON_PROF_OFF }; 55 56 extern char btext[]; 57 extern char etext[]; 58 59 #ifdef GUPROF 60 void 61 nullfunc_loop_profiled() 62 { 63 int i; 64 65 for (i = 0; i < CALIB_SCALE; i++) 66 nullfunc_profiled(); 67 } 68 69 void 70 nullfunc_profiled() 71 { 72 } 73 #endif /* GUPROF */ 74 75 static void 76 kmstartup(dummy) 77 void *dummy; 78 { 79 char *cp; 80 struct gmonparam *p = &_gmonparam; 81 #ifdef GUPROF 82 int cputime_overhead; 83 int empty_loop_time; 84 int i; 85 fptrint_t kmstartup_addr; 86 int mcount_overhead; 87 int mexitcount_overhead; 88 int nullfunc_loop_overhead; 89 int nullfunc_loop_profiled_time; 90 #endif 91 92 /* 93 * Round lowpc and highpc to multiples of the density we're using 94 * so the rest of the scaling (here and in gprof) stays in ints. 95 */ 96 p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER)); 97 p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER)); 98 p->textsize = p->highpc - p->lowpc; 99 printf("Profiling kernel, textsize=%lu [%x..%x]\n", 100 p->textsize, p->lowpc, p->highpc); 101 p->kcountsize = p->textsize / HISTFRACTION; 102 p->hashfraction = HASHFRACTION; 103 p->fromssize = p->textsize / HASHFRACTION; 104 p->tolimit = p->textsize * ARCDENSITY / 100; 105 if (p->tolimit < MINARCS) 106 p->tolimit = MINARCS; 107 else if (p->tolimit > MAXARCS) 108 p->tolimit = MAXARCS; 109 p->tossize = p->tolimit * sizeof(struct tostruct); 110 cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize, 111 M_GPROF, M_NOWAIT); 112 if (cp == 0) { 113 printf("No memory for profiling.\n"); 114 return; 115 } 116 bzero(cp, p->kcountsize + p->tossize + p->fromssize); 117 p->tos = (struct tostruct *)cp; 118 cp += p->tossize; 119 p->kcount = (HISTCOUNTER *)cp; 120 cp += p->kcountsize; 121 p->froms = (u_short *)cp; 122 123 #ifdef GUPROF 124 /* Initialize pointers to overhead counters. */ 125 p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime)); 126 p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount)); 127 p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount)); 128 129 /* 130 * Disable interrupts to avoid interference while we calibrate 131 * things. 132 */ 133 disable_intr(); 134 135 /* 136 * Determine overheads. 137 * XXX this needs to be repeated for each useful timer/counter. 138 */ 139 cputime_overhead = 0; 140 startguprof(p); 141 for (i = 0; i < CALIB_SCALE; i++) 142 cputime_overhead += cputime(); 143 144 empty_loop(); 145 startguprof(p); 146 empty_loop(); 147 empty_loop_time = cputime(); 148 149 nullfunc_loop_profiled(); 150 151 /* 152 * Start profiling. There won't be any normal function calls since 153 * interrupts are disabled, but we will call the profiling routines 154 * directly to determine their overheads. 155 */ 156 p->state = GMON_PROF_HIRES; 157 158 startguprof(p); 159 nullfunc_loop_profiled(); 160 161 startguprof(p); 162 for (i = 0; i < CALIB_SCALE; i++) 163 #if defined(i386) && __GNUC__ >= 2 164 asm("pushl %0; call __mcount; popl %%ecx" 165 : 166 : "i" (profil) 167 : "ax", "bx", "cx", "dx", "memory"); 168 #else 169 #error 170 #endif 171 mcount_overhead = KCOUNT(p, PC_TO_I(p, profil)); 172 173 startguprof(p); 174 for (i = 0; i < CALIB_SCALE; i++) 175 #if defined(i386) && __GNUC__ >= 2 176 asm("call mexitcount; 1:" 177 : : : "ax", "bx", "cx", "dx", "memory"); 178 asm("movl $1b,%0" : "=rm" (kmstartup_addr)); 179 #else 180 #error 181 #endif 182 mexitcount_overhead = KCOUNT(p, PC_TO_I(p, kmstartup_addr)); 183 184 p->state = GMON_PROF_OFF; 185 stopguprof(p); 186 187 enable_intr(); 188 189 nullfunc_loop_profiled_time = 0; 190 for (i = 0; i < 28; i += sizeof(HISTCOUNTER)) { 191 int x; 192 193 x = KCOUNT(p, PC_TO_I(p, 194 (fptrint_t)nullfunc_loop_profiled + i)); 195 nullfunc_loop_profiled_time += x; 196 printf("leaf[%d] = %d sum %d\n", 197 i, x, nullfunc_loop_profiled_time); 198 } 199 #define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE) 200 #define c2n(count, freq) ((int)((count) * 1000000000LL / freq)) 201 printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n", 202 CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)), 203 CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)), 204 CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)), 205 CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)), 206 CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate))); 207 cputime_overhead -= empty_loop_time; 208 mcount_overhead -= empty_loop_time; 209 mexitcount_overhead -= empty_loop_time; 210 211 /*- 212 * Profiling overheads are determined by the times between the 213 * following events: 214 * MC1: mcount() is called 215 * MC2: cputime() (called from mcount()) latches the timer 216 * MC3: mcount() completes 217 * ME1: mexitcount() is called 218 * ME2: cputime() (called from mexitcount()) latches the timer 219 * ME3: mexitcount() completes. 220 * The times between the events vary slightly depending on instruction 221 * combination and cache misses, etc. Attempt to determine the 222 * minimum times. These can be subtracted from the profiling times 223 * without much risk of reducing the profiling times below what they 224 * would be when profiling is not configured. Abbreviate: 225 * ab = minimum time between MC1 and MC3 226 * a = minumum time between MC1 and MC2 227 * b = minimum time between MC2 and MC3 228 * cd = minimum time between ME1 and ME3 229 * c = minimum time between ME1 and ME2 230 * d = minimum time between ME2 and ME3. 231 * These satisfy the relations: 232 * ab <= mcount_overhead (just measured) 233 * a + b <= ab 234 * cd <= mexitcount_overhead (just measured) 235 * c + d <= cd 236 * a + d <= nullfunc_loop_profiled_time (just measured) 237 * a >= 0, b >= 0, c >= 0, d >= 0. 238 * Assume that ab and cd are equal to the minimums. 239 */ 240 p->cputime_overhead = CALIB_DOSCALE(cputime_overhead); 241 p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead); 242 p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead 243 - cputime_overhead); 244 nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time; 245 p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead 246 - nullfunc_loop_overhead) 247 / 4); 248 p->mexitcount_pre_overhead = p->mexitcount_overhead 249 + p->cputime_overhead 250 - p->mexitcount_post_overhead; 251 p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead) 252 - p->mexitcount_post_overhead; 253 p->mcount_post_overhead = p->mcount_overhead 254 + p->cputime_overhead 255 - p->mcount_pre_overhead; 256 printf( 257 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n", 258 c2n(p->cputime_overhead, p->profrate), 259 c2n(p->mcount_overhead, p->profrate), 260 c2n(p->mcount_pre_overhead, p->profrate), 261 c2n(p->mcount_post_overhead, p->profrate), 262 c2n(p->cputime_overhead, p->profrate), 263 c2n(p->mexitcount_overhead, p->profrate), 264 c2n(p->mexitcount_pre_overhead, p->profrate), 265 c2n(p->mexitcount_post_overhead, p->profrate)); 266 printf( 267 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n", 268 p->cputime_overhead, p->mcount_overhead, 269 p->mcount_pre_overhead, p->mcount_post_overhead, 270 p->cputime_overhead, p->mexitcount_overhead, 271 p->mexitcount_pre_overhead, p->mexitcount_post_overhead); 272 #endif /* GUPROF */ 273 } 274 275 /* 276 * Return kernel profiling information. 277 */ 278 static int 279 sysctl_kern_prof SYSCTL_HANDLER_ARGS 280 { 281 int *name = (int *) arg1; 282 u_int namelen = arg2; 283 struct gmonparam *gp = &_gmonparam; 284 int error; 285 int state; 286 287 /* all sysctl names at this level are terminal */ 288 if (namelen != 1) 289 return (ENOTDIR); /* overloaded */ 290 291 switch (name[0]) { 292 case GPROF_STATE: 293 state = gp->state; 294 error = sysctl_handle_int(oidp, &state, 0, req); 295 if (error) 296 return (error); 297 if (!req->newptr) 298 return (0); 299 if (state == GMON_PROF_OFF) { 300 gp->state = state; 301 stopprofclock(&proc0); 302 stopguprof(gp); 303 } else if (state == GMON_PROF_ON) { 304 gp->state = GMON_PROF_OFF; 305 stopguprof(gp); 306 gp->profrate = profhz; 307 startprofclock(&proc0); 308 gp->state = state; 309 #ifdef GUPROF 310 } else if (state == GMON_PROF_HIRES) { 311 gp->state = GMON_PROF_OFF; 312 stopprofclock(&proc0); 313 startguprof(gp); 314 gp->state = state; 315 #endif 316 } else if (state != gp->state) 317 return (EINVAL); 318 return (0); 319 case GPROF_COUNT: 320 return (sysctl_handle_opaque(oidp, 321 gp->kcount, gp->kcountsize, req)); 322 case GPROF_FROMS: 323 return (sysctl_handle_opaque(oidp, 324 gp->froms, gp->fromssize, req)); 325 case GPROF_TOS: 326 return (sysctl_handle_opaque(oidp, 327 gp->tos, gp->tossize, req)); 328 case GPROF_GMONPARAM: 329 return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req)); 330 default: 331 return (EOPNOTSUPP); 332 } 333 /* NOTREACHED */ 334 } 335 336 SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, ""); 337 #endif /* GPROF */ 338 339 /* 340 * Profiling system call. 341 * 342 * The scale factor is a fixed point number with 16 bits of fraction, so that 343 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. 344 */ 345 #ifndef _SYS_SYSPROTO_H_ 346 struct profil_args { 347 caddr_t samples; 348 u_int size; 349 u_int offset; 350 u_int scale; 351 }; 352 #endif 353 /* ARGSUSED */ 354 int 355 profil(p, uap, retval) 356 struct proc *p; 357 register struct profil_args *uap; 358 int *retval; 359 { 360 register struct uprof *upp; 361 int s; 362 363 if (uap->scale > (1 << 16)) 364 return (EINVAL); 365 if (uap->scale == 0) { 366 stopprofclock(p); 367 return (0); 368 } 369 upp = &p->p_stats->p_prof; 370 371 /* Block profile interrupts while changing state. */ 372 s = splstatclock(); 373 upp->pr_off = uap->offset; 374 upp->pr_scale = uap->scale; 375 upp->pr_base = uap->samples; 376 upp->pr_size = uap->size; 377 startprofclock(p); 378 splx(s); 379 380 return (0); 381 } 382 383 /* 384 * Scale is a fixed-point number with the binary point 16 bits 385 * into the value, and is <= 1.0. pc is at most 32 bits, so the 386 * intermediate result is at most 48 bits. 387 */ 388 #define PC_TO_INDEX(pc, prof) \ 389 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 390 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 391 392 /* 393 * Collect user-level profiling statistics; called on a profiling tick, 394 * when a process is running in user-mode. This routine may be called 395 * from an interrupt context. We try to update the user profiling buffers 396 * cheaply with fuswintr() and suswintr(). If that fails, we revert to 397 * an AST that will vector us to trap() with a context in which copyin 398 * and copyout will work. Trap will then call addupc_task(). 399 * 400 * Note that we may (rarely) not get around to the AST soon enough, and 401 * lose profile ticks when the next tick overwrites this one, but in this 402 * case the system is overloaded and the profile is probably already 403 * inaccurate. 404 */ 405 void 406 addupc_intr(p, pc, ticks) 407 register struct proc *p; 408 register u_long pc; 409 u_int ticks; 410 { 411 register struct uprof *prof; 412 register caddr_t addr; 413 register u_int i; 414 register int v; 415 416 if (ticks == 0) 417 return; 418 prof = &p->p_stats->p_prof; 419 if (pc < prof->pr_off || 420 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 421 return; /* out of range; ignore */ 422 423 addr = prof->pr_base + i; 424 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) { 425 prof->pr_addr = pc; 426 prof->pr_ticks = ticks; 427 need_proftick(p); 428 } 429 } 430 431 /* 432 * Much like before, but we can afford to take faults here. If the 433 * update fails, we simply turn off profiling. 434 */ 435 void 436 addupc_task(p, pc, ticks) 437 register struct proc *p; 438 register u_long pc; 439 u_int ticks; 440 { 441 register struct uprof *prof; 442 register caddr_t addr; 443 register u_int i; 444 u_short v; 445 446 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */ 447 if ((p->p_flag & P_PROFIL) == 0 || ticks == 0) 448 return; 449 450 prof = &p->p_stats->p_prof; 451 if (pc < prof->pr_off || 452 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 453 return; 454 455 addr = prof->pr_base + i; 456 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) { 457 v += ticks; 458 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0) 459 return; 460 } 461 stopprofclock(p); 462 } 463