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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)subr_prof.c 8.3 (Berkeley) 9/23/93 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/sysproto.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/mutex.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 #undef MCOUNT 51 52 static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer"); 53 54 static void kmstartup(void *); 55 SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL); 56 57 struct gmonparam _gmonparam = { GMON_PROF_OFF }; 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 #define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */ 70 71 void 72 nullfunc_profiled() 73 { 74 } 75 #endif /* GUPROF */ 76 77 /* 78 * Update the histograms to support extending the text region arbitrarily. 79 * This is done slightly naively (no sparse regions), so will waste slight 80 * amounts of memory, but will overall work nicely enough to allow profiling 81 * of KLDs. 82 */ 83 void 84 kmupetext(uintfptr_t nhighpc) 85 { 86 struct gmonparam np; /* slightly large */ 87 struct gmonparam *p = &_gmonparam; 88 char *cp; 89 90 GIANT_REQUIRED; 91 bcopy(p, &np, sizeof(*p)); 92 np.highpc = ROUNDUP(nhighpc, HISTFRACTION * sizeof(HISTCOUNTER)); 93 if (np.highpc <= p->highpc) 94 return; 95 np.textsize = np.highpc - p->lowpc; 96 np.kcountsize = np.textsize / HISTFRACTION; 97 np.hashfraction = HASHFRACTION; 98 np.fromssize = np.textsize / HASHFRACTION; 99 np.tolimit = np.textsize * ARCDENSITY / 100; 100 if (np.tolimit < MINARCS) 101 np.tolimit = MINARCS; 102 else if (np.tolimit > MAXARCS) 103 np.tolimit = MAXARCS; 104 np.tossize = np.tolimit * sizeof(struct tostruct); 105 cp = malloc(np.kcountsize + np.fromssize + np.tossize, 106 M_GPROF, M_WAITOK); 107 /* 108 * Check for something else extending highpc while we slept. 109 */ 110 if (np.highpc <= p->highpc) { 111 free(cp, M_GPROF); 112 return; 113 } 114 np.tos = (struct tostruct *)cp; 115 cp += np.tossize; 116 np.kcount = (HISTCOUNTER *)cp; 117 cp += np.kcountsize; 118 np.froms = (u_short *)cp; 119 #ifdef GUPROF 120 /* Reinitialize pointers to overhead counters. */ 121 np.cputime_count = &KCOUNT(&np, PC_TO_I(&np, cputime)); 122 np.mcount_count = &KCOUNT(&np, PC_TO_I(&np, mcount)); 123 np.mexitcount_count = &KCOUNT(&np, PC_TO_I(&np, mexitcount)); 124 #endif 125 critical_enter(); 126 bcopy(p->tos, np.tos, p->tossize); 127 bzero((char *)np.tos + p->tossize, np.tossize - p->tossize); 128 bcopy(p->kcount, np.kcount, p->kcountsize); 129 bzero((char *)np.kcount + p->kcountsize, np.kcountsize - 130 p->kcountsize); 131 bcopy(p->froms, np.froms, p->fromssize); 132 bzero((char *)np.froms + p->fromssize, np.fromssize - p->fromssize); 133 cp = (char *)p->tos; 134 bcopy(&np, p, sizeof(*p)); 135 critical_exit(); 136 free(cp, M_GPROF); 137 } 138 139 static void 140 kmstartup(dummy) 141 void *dummy; 142 { 143 char *cp; 144 struct gmonparam *p = &_gmonparam; 145 #ifdef GUPROF 146 int cputime_overhead; 147 int empty_loop_time; 148 int i; 149 int mcount_overhead; 150 int mexitcount_overhead; 151 int nullfunc_loop_overhead; 152 int nullfunc_loop_profiled_time; 153 uintfptr_t tmp_addr; 154 #endif 155 156 /* 157 * Round lowpc and highpc to multiples of the density we're using 158 * so the rest of the scaling (here and in gprof) stays in ints. 159 */ 160 p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER)); 161 p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER)); 162 p->textsize = p->highpc - p->lowpc; 163 printf("Profiling kernel, textsize=%lu [%jx..%jx]\n", 164 p->textsize, (uintmax_t)p->lowpc, (uintmax_t)p->highpc); 165 p->kcountsize = p->textsize / HISTFRACTION; 166 p->hashfraction = HASHFRACTION; 167 p->fromssize = p->textsize / HASHFRACTION; 168 p->tolimit = p->textsize * ARCDENSITY / 100; 169 if (p->tolimit < MINARCS) 170 p->tolimit = MINARCS; 171 else if (p->tolimit > MAXARCS) 172 p->tolimit = MAXARCS; 173 p->tossize = p->tolimit * sizeof(struct tostruct); 174 cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize, 175 M_GPROF, M_WAITOK | M_ZERO); 176 p->tos = (struct tostruct *)cp; 177 cp += p->tossize; 178 p->kcount = (HISTCOUNTER *)cp; 179 cp += p->kcountsize; 180 p->froms = (u_short *)cp; 181 p->histcounter_type = FUNCTION_ALIGNMENT / HISTFRACTION * NBBY; 182 183 #ifdef GUPROF 184 /* Signed counters. */ 185 p->histcounter_type = -p->histcounter_type; 186 187 /* Initialize pointers to overhead counters. */ 188 p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime)); 189 p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount)); 190 p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount)); 191 192 /* 193 * Disable interrupts to avoid interference while we calibrate 194 * things. 195 */ 196 critical_enter(); 197 198 /* 199 * Determine overheads. 200 * XXX this needs to be repeated for each useful timer/counter. 201 */ 202 cputime_overhead = 0; 203 startguprof(p); 204 for (i = 0; i < CALIB_SCALE; i++) 205 cputime_overhead += cputime(); 206 207 empty_loop(); 208 startguprof(p); 209 empty_loop(); 210 empty_loop_time = cputime(); 211 212 nullfunc_loop_profiled(); 213 214 /* 215 * Start profiling. There won't be any normal function calls since 216 * interrupts are disabled, but we will call the profiling routines 217 * directly to determine their overheads. 218 */ 219 p->state = GMON_PROF_HIRES; 220 221 startguprof(p); 222 nullfunc_loop_profiled(); 223 224 startguprof(p); 225 for (i = 0; i < CALIB_SCALE; i++) 226 MCOUNT_OVERHEAD(sys_profil); 227 mcount_overhead = KCOUNT(p, PC_TO_I(p, sys_profil)); 228 229 startguprof(p); 230 for (i = 0; i < CALIB_SCALE; i++) 231 MEXITCOUNT_OVERHEAD(); 232 MEXITCOUNT_OVERHEAD_GETLABEL(tmp_addr); 233 mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr)); 234 235 p->state = GMON_PROF_OFF; 236 stopguprof(p); 237 238 critical_exit(); 239 240 nullfunc_loop_profiled_time = 0; 241 for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled; 242 tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end; 243 tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER)) 244 nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr)); 245 #define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE) 246 #define c2n(count, freq) ((int)((count) * 1000000000LL / freq)) 247 printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n", 248 CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)), 249 CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)), 250 CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)), 251 CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)), 252 CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate))); 253 cputime_overhead -= empty_loop_time; 254 mcount_overhead -= empty_loop_time; 255 mexitcount_overhead -= empty_loop_time; 256 257 /*- 258 * Profiling overheads are determined by the times between the 259 * following events: 260 * MC1: mcount() is called 261 * MC2: cputime() (called from mcount()) latches the timer 262 * MC3: mcount() completes 263 * ME1: mexitcount() is called 264 * ME2: cputime() (called from mexitcount()) latches the timer 265 * ME3: mexitcount() completes. 266 * The times between the events vary slightly depending on instruction 267 * combination and cache misses, etc. Attempt to determine the 268 * minimum times. These can be subtracted from the profiling times 269 * without much risk of reducing the profiling times below what they 270 * would be when profiling is not configured. Abbreviate: 271 * ab = minimum time between MC1 and MC3 272 * a = minimum time between MC1 and MC2 273 * b = minimum time between MC2 and MC3 274 * cd = minimum time between ME1 and ME3 275 * c = minimum time between ME1 and ME2 276 * d = minimum time between ME2 and ME3. 277 * These satisfy the relations: 278 * ab <= mcount_overhead (just measured) 279 * a + b <= ab 280 * cd <= mexitcount_overhead (just measured) 281 * c + d <= cd 282 * a + d <= nullfunc_loop_profiled_time (just measured) 283 * a >= 0, b >= 0, c >= 0, d >= 0. 284 * Assume that ab and cd are equal to the minimums. 285 */ 286 p->cputime_overhead = CALIB_DOSCALE(cputime_overhead); 287 p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead); 288 p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead 289 - cputime_overhead); 290 nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time; 291 p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead 292 - nullfunc_loop_overhead) 293 / 4); 294 p->mexitcount_pre_overhead = p->mexitcount_overhead 295 + p->cputime_overhead 296 - p->mexitcount_post_overhead; 297 p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead) 298 - p->mexitcount_post_overhead; 299 p->mcount_post_overhead = p->mcount_overhead 300 + p->cputime_overhead 301 - p->mcount_pre_overhead; 302 printf( 303 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n", 304 c2n(p->cputime_overhead, p->profrate), 305 c2n(p->mcount_overhead, p->profrate), 306 c2n(p->mcount_pre_overhead, p->profrate), 307 c2n(p->mcount_post_overhead, p->profrate), 308 c2n(p->cputime_overhead, p->profrate), 309 c2n(p->mexitcount_overhead, p->profrate), 310 c2n(p->mexitcount_pre_overhead, p->profrate), 311 c2n(p->mexitcount_post_overhead, p->profrate)); 312 printf( 313 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n", 314 p->cputime_overhead, p->mcount_overhead, 315 p->mcount_pre_overhead, p->mcount_post_overhead, 316 p->cputime_overhead, p->mexitcount_overhead, 317 p->mexitcount_pre_overhead, p->mexitcount_post_overhead); 318 #endif /* GUPROF */ 319 } 320 321 /* 322 * Return kernel profiling information. 323 */ 324 static int 325 sysctl_kern_prof(SYSCTL_HANDLER_ARGS) 326 { 327 int *name = (int *) arg1; 328 u_int namelen = arg2; 329 struct gmonparam *gp = &_gmonparam; 330 int error; 331 int state; 332 333 /* all sysctl names at this level are terminal */ 334 if (namelen != 1) 335 return (ENOTDIR); /* overloaded */ 336 337 switch (name[0]) { 338 case GPROF_STATE: 339 state = gp->state; 340 error = sysctl_handle_int(oidp, &state, 0, req); 341 if (error) 342 return (error); 343 if (!req->newptr) 344 return (0); 345 if (state == GMON_PROF_OFF) { 346 gp->state = state; 347 PROC_LOCK(&proc0); 348 stopprofclock(&proc0); 349 PROC_UNLOCK(&proc0); 350 stopguprof(gp); 351 } else if (state == GMON_PROF_ON) { 352 gp->state = GMON_PROF_OFF; 353 stopguprof(gp); 354 gp->profrate = profhz; 355 PROC_LOCK(&proc0); 356 startprofclock(&proc0); 357 PROC_UNLOCK(&proc0); 358 gp->state = state; 359 #ifdef GUPROF 360 } else if (state == GMON_PROF_HIRES) { 361 gp->state = GMON_PROF_OFF; 362 PROC_LOCK(&proc0); 363 stopprofclock(&proc0); 364 PROC_UNLOCK(&proc0); 365 startguprof(gp); 366 gp->state = state; 367 #endif 368 } else if (state != gp->state) 369 return (EINVAL); 370 return (0); 371 case GPROF_COUNT: 372 return (sysctl_handle_opaque(oidp, 373 gp->kcount, gp->kcountsize, req)); 374 case GPROF_FROMS: 375 return (sysctl_handle_opaque(oidp, 376 gp->froms, gp->fromssize, req)); 377 case GPROF_TOS: 378 return (sysctl_handle_opaque(oidp, 379 gp->tos, gp->tossize, req)); 380 case GPROF_GMONPARAM: 381 return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req)); 382 default: 383 return (EOPNOTSUPP); 384 } 385 /* NOTREACHED */ 386 } 387 388 static SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, ""); 389 #endif /* GPROF */ 390 391 /* 392 * Profiling system call. 393 * 394 * The scale factor is a fixed point number with 16 bits of fraction, so that 395 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. 396 */ 397 #ifndef _SYS_SYSPROTO_H_ 398 struct profil_args { 399 caddr_t samples; 400 size_t size; 401 size_t offset; 402 u_int scale; 403 }; 404 #endif 405 /* ARGSUSED */ 406 int 407 sys_profil(struct thread *td, struct profil_args *uap) 408 { 409 struct uprof *upp; 410 struct proc *p; 411 412 if (uap->scale > (1 << 16)) 413 return (EINVAL); 414 415 p = td->td_proc; 416 if (uap->scale == 0) { 417 PROC_LOCK(p); 418 stopprofclock(p); 419 PROC_UNLOCK(p); 420 return (0); 421 } 422 PROC_LOCK(p); 423 upp = &td->td_proc->p_stats->p_prof; 424 PROC_PROFLOCK(p); 425 upp->pr_off = uap->offset; 426 upp->pr_scale = uap->scale; 427 upp->pr_base = uap->samples; 428 upp->pr_size = uap->size; 429 PROC_PROFUNLOCK(p); 430 startprofclock(p); 431 PROC_UNLOCK(p); 432 433 return (0); 434 } 435 436 /* 437 * Scale is a fixed-point number with the binary point 16 bits 438 * into the value, and is <= 1.0. pc is at most 32 bits, so the 439 * intermediate result is at most 48 bits. 440 */ 441 #define PC_TO_INDEX(pc, prof) \ 442 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 443 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 444 445 /* 446 * Collect user-level profiling statistics; called on a profiling tick, 447 * when a process is running in user-mode. This routine may be called 448 * from an interrupt context. We try to update the user profiling buffers 449 * cheaply with fuswintr() and suswintr(). If that fails, we revert to 450 * an AST that will vector us to trap() with a context in which copyin 451 * and copyout will work. Trap will then call addupc_task(). 452 * 453 * Note that we may (rarely) not get around to the AST soon enough, and 454 * lose profile ticks when the next tick overwrites this one, but in this 455 * case the system is overloaded and the profile is probably already 456 * inaccurate. 457 */ 458 void 459 addupc_intr(struct thread *td, uintfptr_t pc, u_int ticks) 460 { 461 struct uprof *prof; 462 caddr_t addr; 463 u_int i; 464 int v; 465 466 if (ticks == 0) 467 return; 468 prof = &td->td_proc->p_stats->p_prof; 469 PROC_PROFLOCK(td->td_proc); 470 if (pc < prof->pr_off || 471 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { 472 PROC_PROFUNLOCK(td->td_proc); 473 return; /* out of range; ignore */ 474 } 475 476 addr = prof->pr_base + i; 477 PROC_PROFUNLOCK(td->td_proc); 478 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) { 479 td->td_profil_addr = pc; 480 td->td_profil_ticks = ticks; 481 td->td_pflags |= TDP_OWEUPC; 482 thread_lock(td); 483 td->td_flags |= TDF_ASTPENDING; 484 thread_unlock(td); 485 } 486 } 487 488 /* 489 * Much like before, but we can afford to take faults here. If the 490 * update fails, we simply turn off profiling. 491 */ 492 void 493 addupc_task(struct thread *td, uintfptr_t pc, u_int ticks) 494 { 495 struct proc *p = td->td_proc; 496 struct uprof *prof; 497 caddr_t addr; 498 u_int i; 499 u_short v; 500 int stop = 0; 501 502 if (ticks == 0) 503 return; 504 505 PROC_LOCK(p); 506 if (!(p->p_flag & P_PROFIL)) { 507 PROC_UNLOCK(p); 508 return; 509 } 510 p->p_profthreads++; 511 prof = &p->p_stats->p_prof; 512 PROC_PROFLOCK(p); 513 if (pc < prof->pr_off || 514 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { 515 PROC_PROFUNLOCK(p); 516 goto out; 517 } 518 519 addr = prof->pr_base + i; 520 PROC_PROFUNLOCK(p); 521 PROC_UNLOCK(p); 522 if (copyin(addr, &v, sizeof(v)) == 0) { 523 v += ticks; 524 if (copyout(&v, addr, sizeof(v)) == 0) { 525 PROC_LOCK(p); 526 goto out; 527 } 528 } 529 stop = 1; 530 PROC_LOCK(p); 531 532 out: 533 if (--p->p_profthreads == 0) { 534 if (p->p_flag & P_STOPPROF) { 535 wakeup(&p->p_profthreads); 536 p->p_flag &= ~P_STOPPROF; 537 stop = 0; 538 } 539 } 540 if (stop) 541 stopprofclock(p); 542 PROC_UNLOCK(p); 543 } 544