1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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 8.3 (Berkeley) 9/23/93 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/sysproto.h> 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/mutex.h> 43 #include <sys/proc.h> 44 #include <sys/resourcevar.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 #undef MCOUNT 53 54 static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer"); 55 56 static void kmstartup(void *); 57 SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL); 58 59 struct gmonparam _gmonparam = { GMON_PROF_OFF }; 60 61 #ifdef GUPROF 62 void 63 nullfunc_loop_profiled() 64 { 65 int i; 66 67 for (i = 0; i < CALIB_SCALE; i++) 68 nullfunc_profiled(); 69 } 70 71 #define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */ 72 73 void 74 nullfunc_profiled() 75 { 76 } 77 #endif /* GUPROF */ 78 79 /* 80 * Update the histograms to support extending the text region arbitrarily. 81 * This is done slightly naively (no sparse regions), so will waste slight 82 * amounts of memory, but will overall work nicely enough to allow profiling 83 * of KLDs. 84 */ 85 void 86 kmupetext(uintfptr_t nhighpc) 87 { 88 struct gmonparam np; /* slightly large */ 89 struct gmonparam *p = &_gmonparam; 90 char *cp; 91 92 GIANT_REQUIRED; 93 bcopy(p, &np, sizeof(*p)); 94 np.highpc = ROUNDUP(nhighpc, HISTFRACTION * sizeof(HISTCOUNTER)); 95 if (np.highpc <= p->highpc) 96 return; 97 np.textsize = np.highpc - p->lowpc; 98 np.kcountsize = np.textsize / HISTFRACTION; 99 np.hashfraction = HASHFRACTION; 100 np.fromssize = np.textsize / HASHFRACTION; 101 np.tolimit = np.textsize * ARCDENSITY / 100; 102 if (np.tolimit < MINARCS) 103 np.tolimit = MINARCS; 104 else if (np.tolimit > MAXARCS) 105 np.tolimit = MAXARCS; 106 np.tossize = np.tolimit * sizeof(struct tostruct); 107 cp = malloc(np.kcountsize + np.fromssize + np.tossize, 108 M_GPROF, M_WAITOK); 109 /* 110 * Check for something else extending highpc while we slept. 111 */ 112 if (np.highpc <= p->highpc) { 113 free(cp, M_GPROF); 114 return; 115 } 116 np.tos = (struct tostruct *)cp; 117 cp += np.tossize; 118 np.kcount = (HISTCOUNTER *)cp; 119 cp += np.kcountsize; 120 np.froms = (u_short *)cp; 121 #ifdef GUPROF 122 /* Reinitialize pointers to overhead counters. */ 123 np.cputime_count = &KCOUNT(&np, PC_TO_I(&np, cputime)); 124 np.mcount_count = &KCOUNT(&np, PC_TO_I(&np, mcount)); 125 np.mexitcount_count = &KCOUNT(&np, PC_TO_I(&np, mexitcount)); 126 #endif 127 critical_enter(); 128 bcopy(p->tos, np.tos, p->tossize); 129 bzero((char *)np.tos + p->tossize, np.tossize - p->tossize); 130 bcopy(p->kcount, np.kcount, p->kcountsize); 131 bzero((char *)np.kcount + p->kcountsize, np.kcountsize - 132 p->kcountsize); 133 bcopy(p->froms, np.froms, p->fromssize); 134 bzero((char *)np.froms + p->fromssize, np.fromssize - p->fromssize); 135 cp = (char *)p->tos; 136 bcopy(&np, p, sizeof(*p)); 137 critical_exit(); 138 free(cp, M_GPROF); 139 } 140 141 static void 142 kmstartup(void *dummy) 143 { 144 char *cp; 145 struct gmonparam *p = &_gmonparam; 146 #ifdef GUPROF 147 int cputime_overhead; 148 int empty_loop_time; 149 int i; 150 int mcount_overhead; 151 int mexitcount_overhead; 152 int nullfunc_loop_overhead; 153 int nullfunc_loop_profiled_time; 154 uintfptr_t tmp_addr; 155 #endif 156 157 /* 158 * Round lowpc and highpc to multiples of the density we're using 159 * so the rest of the scaling (here and in gprof) stays in ints. 160 */ 161 p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER)); 162 p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER)); 163 p->textsize = p->highpc - p->lowpc; 164 printf("Profiling kernel, textsize=%lu [%jx..%jx]\n", 165 p->textsize, (uintmax_t)p->lowpc, (uintmax_t)p->highpc); 166 p->kcountsize = p->textsize / HISTFRACTION; 167 p->hashfraction = HASHFRACTION; 168 p->fromssize = p->textsize / HASHFRACTION; 169 p->tolimit = p->textsize * ARCDENSITY / 100; 170 if (p->tolimit < MINARCS) 171 p->tolimit = MINARCS; 172 else if (p->tolimit > MAXARCS) 173 p->tolimit = MAXARCS; 174 p->tossize = p->tolimit * sizeof(struct tostruct); 175 cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize, 176 M_GPROF, M_WAITOK | M_ZERO); 177 p->tos = (struct tostruct *)cp; 178 cp += p->tossize; 179 p->kcount = (HISTCOUNTER *)cp; 180 cp += p->kcountsize; 181 p->froms = (u_short *)cp; 182 p->histcounter_type = FUNCTION_ALIGNMENT / HISTFRACTION * NBBY; 183 184 #ifdef GUPROF 185 /* Signed counters. */ 186 p->histcounter_type = -p->histcounter_type; 187 188 /* Initialize pointers to overhead counters. */ 189 p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime)); 190 p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount)); 191 p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount)); 192 193 /* 194 * Disable interrupts to avoid interference while we calibrate 195 * things. 196 */ 197 critical_enter(); 198 199 /* 200 * Determine overheads. 201 * XXX this needs to be repeated for each useful timer/counter. 202 */ 203 cputime_overhead = 0; 204 startguprof(p); 205 for (i = 0; i < CALIB_SCALE; i++) 206 cputime_overhead += cputime(); 207 208 empty_loop(); 209 startguprof(p); 210 empty_loop(); 211 empty_loop_time = cputime(); 212 213 nullfunc_loop_profiled(); 214 215 /* 216 * Start profiling. There won't be any normal function calls since 217 * interrupts are disabled, but we will call the profiling routines 218 * directly to determine their overheads. 219 */ 220 p->state = GMON_PROF_HIRES; 221 222 startguprof(p); 223 nullfunc_loop_profiled(); 224 225 startguprof(p); 226 for (i = 0; i < CALIB_SCALE; i++) 227 MCOUNT_OVERHEAD(sys_profil); 228 mcount_overhead = KCOUNT(p, PC_TO_I(p, sys_profil)); 229 230 startguprof(p); 231 for (i = 0; i < CALIB_SCALE; i++) 232 MEXITCOUNT_OVERHEAD(); 233 MEXITCOUNT_OVERHEAD_GETLABEL(tmp_addr); 234 mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr)); 235 236 p->state = GMON_PROF_OFF; 237 stopguprof(p); 238 239 critical_exit(); 240 241 nullfunc_loop_profiled_time = 0; 242 for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled; 243 tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end; 244 tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER)) 245 nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr)); 246 #define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE) 247 #define c2n(count, freq) ((int)((count) * 1000000000LL / freq)) 248 printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n", 249 CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)), 250 CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)), 251 CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)), 252 CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)), 253 CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate))); 254 cputime_overhead -= empty_loop_time; 255 mcount_overhead -= empty_loop_time; 256 mexitcount_overhead -= empty_loop_time; 257 258 /*- 259 * Profiling overheads are determined by the times between the 260 * following events: 261 * MC1: mcount() is called 262 * MC2: cputime() (called from mcount()) latches the timer 263 * MC3: mcount() completes 264 * ME1: mexitcount() is called 265 * ME2: cputime() (called from mexitcount()) latches the timer 266 * ME3: mexitcount() completes. 267 * The times between the events vary slightly depending on instruction 268 * combination and cache misses, etc. Attempt to determine the 269 * minimum times. These can be subtracted from the profiling times 270 * without much risk of reducing the profiling times below what they 271 * would be when profiling is not configured. Abbreviate: 272 * ab = minimum time between MC1 and MC3 273 * a = minimum time between MC1 and MC2 274 * b = minimum time between MC2 and MC3 275 * cd = minimum time between ME1 and ME3 276 * c = minimum time between ME1 and ME2 277 * d = minimum time between ME2 and ME3. 278 * These satisfy the relations: 279 * ab <= mcount_overhead (just measured) 280 * a + b <= ab 281 * cd <= mexitcount_overhead (just measured) 282 * c + d <= cd 283 * a + d <= nullfunc_loop_profiled_time (just measured) 284 * a >= 0, b >= 0, c >= 0, d >= 0. 285 * Assume that ab and cd are equal to the minimums. 286 */ 287 p->cputime_overhead = CALIB_DOSCALE(cputime_overhead); 288 p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead); 289 p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead 290 - cputime_overhead); 291 nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time; 292 p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead 293 - nullfunc_loop_overhead) 294 / 4); 295 p->mexitcount_pre_overhead = p->mexitcount_overhead 296 + p->cputime_overhead 297 - p->mexitcount_post_overhead; 298 p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead) 299 - p->mexitcount_post_overhead; 300 p->mcount_post_overhead = p->mcount_overhead 301 + p->cputime_overhead 302 - p->mcount_pre_overhead; 303 printf( 304 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n", 305 c2n(p->cputime_overhead, p->profrate), 306 c2n(p->mcount_overhead, p->profrate), 307 c2n(p->mcount_pre_overhead, p->profrate), 308 c2n(p->mcount_post_overhead, p->profrate), 309 c2n(p->cputime_overhead, p->profrate), 310 c2n(p->mexitcount_overhead, p->profrate), 311 c2n(p->mexitcount_pre_overhead, p->profrate), 312 c2n(p->mexitcount_post_overhead, p->profrate)); 313 printf( 314 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n", 315 p->cputime_overhead, p->mcount_overhead, 316 p->mcount_pre_overhead, p->mcount_post_overhead, 317 p->cputime_overhead, p->mexitcount_overhead, 318 p->mexitcount_pre_overhead, p->mexitcount_post_overhead); 319 #endif /* GUPROF */ 320 } 321 322 /* 323 * Return kernel profiling information. 324 */ 325 static int 326 sysctl_kern_prof(SYSCTL_HANDLER_ARGS) 327 { 328 int *name = (int *) arg1; 329 u_int namelen = arg2; 330 struct gmonparam *gp = &_gmonparam; 331 int error; 332 int state; 333 334 /* all sysctl names at this level are terminal */ 335 if (namelen != 1) 336 return (ENOTDIR); /* overloaded */ 337 338 switch (name[0]) { 339 case GPROF_STATE: 340 state = gp->state; 341 error = sysctl_handle_int(oidp, &state, 0, req); 342 if (error) 343 return (error); 344 if (!req->newptr) 345 return (0); 346 if (state == GMON_PROF_OFF) { 347 gp->state = state; 348 PROC_LOCK(&proc0); 349 stopprofclock(&proc0); 350 PROC_UNLOCK(&proc0); 351 stopguprof(gp); 352 } else if (state == GMON_PROF_ON) { 353 gp->state = GMON_PROF_OFF; 354 stopguprof(gp); 355 gp->profrate = profhz; 356 PROC_LOCK(&proc0); 357 startprofclock(&proc0); 358 PROC_UNLOCK(&proc0); 359 gp->state = state; 360 #ifdef GUPROF 361 } else if (state == GMON_PROF_HIRES) { 362 gp->state = GMON_PROF_OFF; 363 PROC_LOCK(&proc0); 364 stopprofclock(&proc0); 365 PROC_UNLOCK(&proc0); 366 startguprof(gp); 367 gp->state = state; 368 #endif 369 } else if (state != gp->state) 370 return (EINVAL); 371 return (0); 372 case GPROF_COUNT: 373 return (sysctl_handle_opaque(oidp, 374 gp->kcount, gp->kcountsize, req)); 375 case GPROF_FROMS: 376 return (sysctl_handle_opaque(oidp, 377 gp->froms, gp->fromssize, req)); 378 case GPROF_TOS: 379 return (sysctl_handle_opaque(oidp, 380 gp->tos, gp->tossize, req)); 381 case GPROF_GMONPARAM: 382 return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req)); 383 default: 384 return (EOPNOTSUPP); 385 } 386 /* NOTREACHED */ 387 } 388 389 static SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, ""); 390 #endif /* GPROF */ 391 392 /* 393 * Profiling system call. 394 * 395 * The scale factor is a fixed point number with 16 bits of fraction, so that 396 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. 397 */ 398 #ifndef _SYS_SYSPROTO_H_ 399 struct profil_args { 400 caddr_t samples; 401 size_t size; 402 size_t offset; 403 u_int scale; 404 }; 405 #endif 406 /* ARGSUSED */ 407 int 408 sys_profil(struct thread *td, struct profil_args *uap) 409 { 410 struct uprof *upp; 411 struct proc *p; 412 413 if (uap->scale > (1 << 16)) 414 return (EINVAL); 415 416 p = td->td_proc; 417 if (uap->scale == 0) { 418 PROC_LOCK(p); 419 stopprofclock(p); 420 PROC_UNLOCK(p); 421 return (0); 422 } 423 PROC_LOCK(p); 424 upp = &td->td_proc->p_stats->p_prof; 425 PROC_PROFLOCK(p); 426 upp->pr_off = uap->offset; 427 upp->pr_scale = uap->scale; 428 upp->pr_base = uap->samples; 429 upp->pr_size = uap->size; 430 PROC_PROFUNLOCK(p); 431 startprofclock(p); 432 PROC_UNLOCK(p); 433 434 return (0); 435 } 436 437 /* 438 * Scale is a fixed-point number with the binary point 16 bits 439 * into the value, and is <= 1.0. pc is at most 32 bits, so the 440 * intermediate result is at most 48 bits. 441 */ 442 #define PC_TO_INDEX(pc, prof) \ 443 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 444 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 445 446 /* 447 * Collect user-level profiling statistics; called on a profiling tick, 448 * when a process is running in user-mode. This routine may be called 449 * from an interrupt context. We perform the update with an AST 450 * that will vector us to trap() with a context in which copyin and 451 * 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; 462 463 if (ticks == 0) 464 return; 465 prof = &td->td_proc->p_stats->p_prof; 466 PROC_PROFLOCK(td->td_proc); 467 if (pc < prof->pr_off || PC_TO_INDEX(pc, prof) >= prof->pr_size) { 468 PROC_PROFUNLOCK(td->td_proc); 469 return; /* out of range; ignore */ 470 } 471 472 PROC_PROFUNLOCK(td->td_proc); 473 td->td_profil_addr = pc; 474 td->td_profil_ticks = ticks; 475 td->td_pflags |= TDP_OWEUPC; 476 thread_lock(td); 477 td->td_flags |= TDF_ASTPENDING; 478 thread_unlock(td); 479 } 480 481 /* 482 * Actually update the profiling statistics. If the update fails, we 483 * simply turn off profiling. 484 */ 485 void 486 addupc_task(struct thread *td, uintfptr_t pc, u_int ticks) 487 { 488 struct proc *p = td->td_proc; 489 struct uprof *prof; 490 caddr_t addr; 491 u_int i; 492 u_short v; 493 int stop = 0; 494 495 if (ticks == 0) 496 return; 497 498 PROC_LOCK(p); 499 if (!(p->p_flag & P_PROFIL)) { 500 PROC_UNLOCK(p); 501 return; 502 } 503 p->p_profthreads++; 504 prof = &p->p_stats->p_prof; 505 PROC_PROFLOCK(p); 506 if (pc < prof->pr_off || 507 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { 508 PROC_PROFUNLOCK(p); 509 goto out; 510 } 511 512 addr = prof->pr_base + i; 513 PROC_PROFUNLOCK(p); 514 PROC_UNLOCK(p); 515 if (copyin(addr, &v, sizeof(v)) == 0) { 516 v += ticks; 517 if (copyout(&v, addr, sizeof(v)) == 0) { 518 PROC_LOCK(p); 519 goto out; 520 } 521 } 522 stop = 1; 523 PROC_LOCK(p); 524 525 out: 526 if (--p->p_profthreads == 0) { 527 if (p->p_flag & P_STOPPROF) { 528 wakeup(&p->p_profthreads); 529 p->p_flag &= ~P_STOPPROF; 530 stop = 0; 531 } 532 } 533 if (stop) 534 stopprofclock(p); 535 PROC_UNLOCK(p); 536 } 537