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
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193 194 nullfunc_loop_profiled_time = 0; 195 for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled; 196 tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end; 197 tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER)) 198 nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr)); 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 */ 278static int 279sysctl_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 336SYSCTL_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_ 346struct profil_args { 347 caddr_t samples; 348 size_t size; 349 size_t offset; 350 u_int scale; 351}; 352#endif 353/* ARGSUSED */ 354int 355profil(p, uap) 356 struct proc *p; 357 register struct profil_args *uap; 358{ 359 register struct uprof *upp; 360 int s; 361 362 if (uap->scale > (1 << 16)) 363 return (EINVAL); 364 if (uap->scale == 0) { 365 stopprofclock(p); 366 return (0); 367 } 368 upp = &p->p_stats->p_prof; 369 370 /* Block profile interrupts while changing state. */ 371 s = splstatclock(); 372 upp->pr_off = uap->offset; 373 upp->pr_scale = uap->scale; 374 upp->pr_base = uap->samples; 375 upp->pr_size = uap->size; 376 startprofclock(p); 377 splx(s); 378 379 return (0); 380} 381 382/* 383 * Scale is a fixed-point number with the binary point 16 bits 384 * into the value, and is <= 1.0. pc is at most 32 bits, so the 385 * intermediate result is at most 48 bits. 386 */ 387#define PC_TO_INDEX(pc, prof) \ 388 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 389 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 390 391/* 392 * Collect user-level profiling statistics; called on a profiling tick, 393 * when a process is running in user-mode. This routine may be called 394 * from an interrupt context. We try to update the user profiling buffers 395 * cheaply with fuswintr() and suswintr(). If that fails, we revert to 396 * an AST that will vector us to trap() with a context in which copyin 397 * and copyout will work. Trap will then call addupc_task(). 398 * 399 * Note that we may (rarely) not get around to the AST soon enough, and 400 * lose profile ticks when the next tick overwrites this one, but in this 401 * case the system is overloaded and the profile is probably already 402 * inaccurate. 403 */ 404void 405addupc_intr(p, pc, ticks) 406 register struct proc *p; 407 register uintptr_t pc; 408 u_int ticks; 409{ 410 register struct uprof *prof; 411 register caddr_t addr; 412 register u_int i; 413 register int v; 414 415 if (ticks == 0) 416 return; 417 prof = &p->p_stats->p_prof; 418 if (pc < prof->pr_off || 419 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 420 return; /* out of range; ignore */ 421 422 addr = prof->pr_base + i; 423 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) { 424 prof->pr_addr = pc; 425 prof->pr_ticks = ticks; 426 need_proftick(p); 427 } 428} 429 430/* 431 * Much like before, but we can afford to take faults here. If the 432 * update fails, we simply turn off profiling. 433 */ 434void 435addupc_task(p, pc, ticks) 436 register struct proc *p; 437 register uintptr_t pc; 438 u_int ticks; 439{ 440 register struct uprof *prof; 441 register caddr_t addr; 442 register u_int i; 443 u_short v; 444 445 /* Testing PS_PROFIL may be unnecessary, but is certainly safe. */ 446 mtx_lock_spin(&sched_lock); 447 if ((p->p_sflag & PS_PROFIL) == 0 || ticks == 0) { 448 mtx_unlock_spin(&sched_lock); 449 return; 450 } 451 mtx_unlock_spin(&sched_lock); 452 453 prof = &p->p_stats->p_prof; 454 if (pc < prof->pr_off || 455 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 456 return; 457 458 addr = prof->pr_base + i; 459 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) { 460 v += ticks; 461 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0) 462 return; 463 } 464 stopprofclock(p); 465}
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