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 1.27 1998/07/14 05:09:46 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 MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer"); 52 53 static void kmstartup __P((void *)); 54 SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL) 55 56 struct gmonparam _gmonparam = { GMON_PROF_OFF }; 57 58 #ifdef GUPROF 59 void 60 nullfunc_loop_profiled() 61 { 62 int i; 63 64 for (i = 0; i < CALIB_SCALE; i++) 65 nullfunc_profiled(); 66 } 67 68 #define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */ 69 70 void 71 nullfunc_profiled() 72 { 73 } 74 #endif /* GUPROF */ 75 76 static void 77 kmstartup(dummy) 78 void *dummy; 79 { 80 char *cp; 81 struct gmonparam *p = &_gmonparam; 82 #ifdef GUPROF 83 int cputime_overhead; 84 int empty_loop_time; 85 int i; 86 int mcount_overhead; 87 int mexitcount_overhead; 88 int nullfunc_loop_overhead; 89 int nullfunc_loop_profiled_time; 90 uintfptr_t tmp_addr; 91 #endif 92 93 /* 94 * Round lowpc and highpc to multiples of the density we're using 95 * so the rest of the scaling (here and in gprof) stays in ints. 96 */ 97 p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER)); 98 p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER)); 99 p->textsize = p->highpc - p->lowpc; 100 printf("Profiling kernel, textsize=%lu [%x..%x]\n", 101 p->textsize, p->lowpc, p->highpc); 102 p->kcountsize = p->textsize / HISTFRACTION; 103 p->hashfraction = HASHFRACTION; 104 p->fromssize = p->textsize / HASHFRACTION; 105 p->tolimit = p->textsize * ARCDENSITY / 100; 106 if (p->tolimit < MINARCS) 107 p->tolimit = MINARCS; 108 else if (p->tolimit > MAXARCS) 109 p->tolimit = MAXARCS; 110 p->tossize = p->tolimit * sizeof(struct tostruct); 111 cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize, 112 M_GPROF, M_NOWAIT); 113 if (cp == 0) { 114 printf("No memory for profiling.\n"); 115 return; 116 } 117 bzero(cp, p->kcountsize + p->tossize + p->fromssize); 118 p->tos = (struct tostruct *)cp; 119 cp += p->tossize; 120 p->kcount = (HISTCOUNTER *)cp; 121 cp += p->kcountsize; 122 p->froms = (u_short *)cp; 123 124 #ifdef GUPROF 125 /* Initialize pointers to overhead counters. */ 126 p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime)); 127 p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount)); 128 p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount)); 129 130 /* 131 * Disable interrupts to avoid interference while we calibrate 132 * things. 133 */ 134 disable_intr(); 135 136 /* 137 * Determine overheads. 138 * XXX this needs to be repeated for each useful timer/counter. 139 */ 140 cputime_overhead = 0; 141 startguprof(p); 142 for (i = 0; i < CALIB_SCALE; i++) 143 cputime_overhead += cputime(); 144 145 empty_loop(); 146 startguprof(p); 147 empty_loop(); 148 empty_loop_time = cputime(); 149 150 nullfunc_loop_profiled(); 151 152 /* 153 * Start profiling. There won't be any normal function calls since 154 * interrupts are disabled, but we will call the profiling routines 155 * directly to determine their overheads. 156 */ 157 p->state = GMON_PROF_HIRES; 158 159 startguprof(p); 160 nullfunc_loop_profiled(); 161 162 startguprof(p); 163 for (i = 0; i < CALIB_SCALE; i++) 164 #if defined(__i386__) && __GNUC__ >= 2 165 __asm("pushl %0; call __mcount; popl %%ecx" 166 : 167 : "i" (profil) 168 : "ax", "bx", "cx", "dx", "memory"); 169 #else 170 #error 171 #endif 172 mcount_overhead = KCOUNT(p, PC_TO_I(p, profil)); 173 174 startguprof(p); 175 for (i = 0; i < CALIB_SCALE; i++) 176 #if defined(__i386__) && __GNUC__ >= 2 177 __asm("call mexitcount; 1:" 178 : : : "ax", "bx", "cx", "dx", "memory"); 179 __asm("movl $1b,%0" : "=rm" (tmp_addr)); 180 #else 181 #error 182 #endif 183 mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr)); 184 185 p->state = GMON_PROF_OFF; 186 stopguprof(p); 187 188 enable_intr(); 189 190 nullfunc_loop_profiled_time = 0; 191 for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled; 192 tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end; 193 tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER)) 194 nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr)); 195 #define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE) 196 #define c2n(count, freq) ((int)((count) * 1000000000LL / freq)) 197 printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n", 198 CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)), 199 CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)), 200 CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)), 201 CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)), 202 CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate))); 203 cputime_overhead -= empty_loop_time; 204 mcount_overhead -= empty_loop_time; 205 mexitcount_overhead -= empty_loop_time; 206 207 /*- 208 * Profiling overheads are determined by the times between the 209 * following events: 210 * MC1: mcount() is called 211 * MC2: cputime() (called from mcount()) latches the timer 212 * MC3: mcount() completes 213 * ME1: mexitcount() is called 214 * ME2: cputime() (called from mexitcount()) latches the timer 215 * ME3: mexitcount() completes. 216 * The times between the events vary slightly depending on instruction 217 * combination and cache misses, etc. Attempt to determine the 218 * minimum times. These can be subtracted from the profiling times 219 * without much risk of reducing the profiling times below what they 220 * would be when profiling is not configured. Abbreviate: 221 * ab = minimum time between MC1 and MC3 222 * a = minumum time between MC1 and MC2 223 * b = minimum time between MC2 and MC3 224 * cd = minimum time between ME1 and ME3 225 * c = minimum time between ME1 and ME2 226 * d = minimum time between ME2 and ME3. 227 * These satisfy the relations: 228 * ab <= mcount_overhead (just measured) 229 * a + b <= ab 230 * cd <= mexitcount_overhead (just measured) 231 * c + d <= cd 232 * a + d <= nullfunc_loop_profiled_time (just measured) 233 * a >= 0, b >= 0, c >= 0, d >= 0. 234 * Assume that ab and cd are equal to the minimums. 235 */ 236 p->cputime_overhead = CALIB_DOSCALE(cputime_overhead); 237 p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead); 238 p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead 239 - cputime_overhead); 240 nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time; 241 p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead 242 - nullfunc_loop_overhead) 243 / 4); 244 p->mexitcount_pre_overhead = p->mexitcount_overhead 245 + p->cputime_overhead 246 - p->mexitcount_post_overhead; 247 p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead) 248 - p->mexitcount_post_overhead; 249 p->mcount_post_overhead = p->mcount_overhead 250 + p->cputime_overhead 251 - p->mcount_pre_overhead; 252 printf( 253 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n", 254 c2n(p->cputime_overhead, p->profrate), 255 c2n(p->mcount_overhead, p->profrate), 256 c2n(p->mcount_pre_overhead, p->profrate), 257 c2n(p->mcount_post_overhead, p->profrate), 258 c2n(p->cputime_overhead, p->profrate), 259 c2n(p->mexitcount_overhead, p->profrate), 260 c2n(p->mexitcount_pre_overhead, p->profrate), 261 c2n(p->mexitcount_post_overhead, p->profrate)); 262 printf( 263 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n", 264 p->cputime_overhead, p->mcount_overhead, 265 p->mcount_pre_overhead, p->mcount_post_overhead, 266 p->cputime_overhead, p->mexitcount_overhead, 267 p->mexitcount_pre_overhead, p->mexitcount_post_overhead); 268 #endif /* GUPROF */ 269 } 270 271 /* 272 * Return kernel profiling information. 273 */ 274 static int 275 sysctl_kern_prof SYSCTL_HANDLER_ARGS 276 { 277 int *name = (int *) arg1; 278 u_int namelen = arg2; 279 struct gmonparam *gp = &_gmonparam; 280 int error; 281 int state; 282 283 /* all sysctl names at this level are terminal */ 284 if (namelen != 1) 285 return (ENOTDIR); /* overloaded */ 286 287 switch (name[0]) { 288 case GPROF_STATE: 289 state = gp->state; 290 error = sysctl_handle_int(oidp, &state, 0, req); 291 if (error) 292 return (error); 293 if (!req->newptr) 294 return (0); 295 if (state == GMON_PROF_OFF) { 296 gp->state = state; 297 stopprofclock(&proc0); 298 stopguprof(gp); 299 } else if (state == GMON_PROF_ON) { 300 gp->state = GMON_PROF_OFF; 301 stopguprof(gp); 302 gp->profrate = profhz; 303 startprofclock(&proc0); 304 gp->state = state; 305 #ifdef GUPROF 306 } else if (state == GMON_PROF_HIRES) { 307 gp->state = GMON_PROF_OFF; 308 stopprofclock(&proc0); 309 startguprof(gp); 310 gp->state = state; 311 #endif 312 } else if (state != gp->state) 313 return (EINVAL); 314 return (0); 315 case GPROF_COUNT: 316 return (sysctl_handle_opaque(oidp, 317 gp->kcount, gp->kcountsize, req)); 318 case GPROF_FROMS: 319 return (sysctl_handle_opaque(oidp, 320 gp->froms, gp->fromssize, req)); 321 case GPROF_TOS: 322 return (sysctl_handle_opaque(oidp, 323 gp->tos, gp->tossize, req)); 324 case GPROF_GMONPARAM: 325 return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req)); 326 default: 327 return (EOPNOTSUPP); 328 } 329 /* NOTREACHED */ 330 } 331 332 SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, ""); 333 #endif /* GPROF */ 334 335 /* 336 * Profiling system call. 337 * 338 * The scale factor is a fixed point number with 16 bits of fraction, so that 339 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. 340 */ 341 #ifndef _SYS_SYSPROTO_H_ 342 struct profil_args { 343 caddr_t samples; 344 size_t size; 345 size_t offset; 346 u_int scale; 347 }; 348 #endif 349 /* ARGSUSED */ 350 int 351 profil(p, uap) 352 struct proc *p; 353 register struct profil_args *uap; 354 { 355 register struct uprof *upp; 356 int s; 357 358 if (uap->scale > (1 << 16)) 359 return (EINVAL); 360 if (uap->scale == 0) { 361 stopprofclock(p); 362 return (0); 363 } 364 upp = &p->p_stats->p_prof; 365 366 /* Block profile interrupts while changing state. */ 367 s = splstatclock(); 368 upp->pr_off = uap->offset; 369 upp->pr_scale = uap->scale; 370 upp->pr_base = uap->samples; 371 upp->pr_size = uap->size; 372 startprofclock(p); 373 splx(s); 374 375 return (0); 376 } 377 378 /* 379 * Scale is a fixed-point number with the binary point 16 bits 380 * into the value, and is <= 1.0. pc is at most 32 bits, so the 381 * intermediate result is at most 48 bits. 382 */ 383 #define PC_TO_INDEX(pc, prof) \ 384 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 385 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 386 387 /* 388 * Collect user-level profiling statistics; called on a profiling tick, 389 * when a process is running in user-mode. This routine may be called 390 * from an interrupt context. We try to update the user profiling buffers 391 * cheaply with fuswintr() and suswintr(). If that fails, we revert to 392 * an AST that will vector us to trap() with a context in which copyin 393 * and copyout will work. Trap will then call addupc_task(). 394 * 395 * Note that we may (rarely) not get around to the AST soon enough, and 396 * lose profile ticks when the next tick overwrites this one, but in this 397 * case the system is overloaded and the profile is probably already 398 * inaccurate. 399 */ 400 void 401 addupc_intr(p, pc, ticks) 402 register struct proc *p; 403 register u_long pc; 404 u_int ticks; 405 { 406 register struct uprof *prof; 407 register caddr_t addr; 408 register u_int i; 409 register int v; 410 411 if (ticks == 0) 412 return; 413 prof = &p->p_stats->p_prof; 414 if (pc < prof->pr_off || 415 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 416 return; /* out of range; ignore */ 417 418 addr = prof->pr_base + i; 419 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) { 420 prof->pr_addr = pc; 421 prof->pr_ticks = ticks; 422 need_proftick(p); 423 } 424 } 425 426 /* 427 * Much like before, but we can afford to take faults here. If the 428 * update fails, we simply turn off profiling. 429 */ 430 void 431 addupc_task(p, pc, ticks) 432 register struct proc *p; 433 register u_long pc; 434 u_int ticks; 435 { 436 register struct uprof *prof; 437 register caddr_t addr; 438 register u_int i; 439 u_short v; 440 441 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */ 442 if ((p->p_flag & P_PROFIL) == 0 || ticks == 0) 443 return; 444 445 prof = &p->p_stats->p_prof; 446 if (pc < prof->pr_off || 447 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 448 return; 449 450 addr = prof->pr_base + i; 451 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) { 452 v += ticks; 453 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0) 454 return; 455 } 456 stopprofclock(p); 457 } 458