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 * $FreeBSD$ 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/ipl.h> 46 #include <machine/cpu.h> 47 48 #ifdef GPROF 49 #include <sys/malloc.h> 50 #include <sys/gmon.h> 51 #undef MCOUNT 52 53 static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer"); 54 55 static void kmstartup __P((void *)); 56 SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL) 57 58 struct gmonparam _gmonparam = { GMON_PROF_OFF }; 59 60 #ifdef GUPROF 61 #include <machine/asmacros.h> 62 63 void 64 nullfunc_loop_profiled() 65 { 66 int i; 67 68 for (i = 0; i < CALIB_SCALE; i++) 69 nullfunc_profiled(); 70 } 71 72 #define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */ 73 74 void 75 nullfunc_profiled() 76 { 77 } 78 #endif /* GUPROF */ 79 80 static void 81 kmstartup(dummy) 82 void *dummy; 83 { 84 char *cp; 85 struct gmonparam *p = &_gmonparam; 86 #ifdef GUPROF 87 int cputime_overhead; 88 int empty_loop_time; 89 int i; 90 int mcount_overhead; 91 int mexitcount_overhead; 92 int nullfunc_loop_overhead; 93 int nullfunc_loop_profiled_time; 94 uintfptr_t tmp_addr; 95 #endif 96 int intrstate; 97 98 /* 99 * Round lowpc and highpc to multiples of the density we're using 100 * so the rest of the scaling (here and in gprof) stays in ints. 101 */ 102 p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER)); 103 p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER)); 104 p->textsize = p->highpc - p->lowpc; 105 printf("Profiling kernel, textsize=%lu [%x..%x]\n", 106 p->textsize, p->lowpc, p->highpc); 107 p->kcountsize = p->textsize / HISTFRACTION; 108 p->hashfraction = HASHFRACTION; 109 p->fromssize = p->textsize / HASHFRACTION; 110 p->tolimit = p->textsize * ARCDENSITY / 100; 111 if (p->tolimit < MINARCS) 112 p->tolimit = MINARCS; 113 else if (p->tolimit > MAXARCS) 114 p->tolimit = MAXARCS; 115 p->tossize = p->tolimit * sizeof(struct tostruct); 116 cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize, 117 M_GPROF, M_NOWAIT); 118 if (cp == 0) { 119 printf("No memory for profiling.\n"); 120 return; 121 } 122 bzero(cp, p->kcountsize + p->tossize + p->fromssize); 123 p->tos = (struct tostruct *)cp; 124 cp += p->tossize; 125 p->kcount = (HISTCOUNTER *)cp; 126 cp += p->kcountsize; 127 p->froms = (u_short *)cp; 128 129 #ifdef GUPROF 130 /* Initialize pointers to overhead counters. */ 131 p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime)); 132 p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount)); 133 p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount)); 134 135 /* 136 * Disable interrupts to avoid interference while we calibrate 137 * things. 138 */ 139 intrstate = save_intr(); 140 disable_intr(); 141 142 /* 143 * Determine overheads. 144 * XXX this needs to be repeated for each useful timer/counter. 145 */ 146 cputime_overhead = 0; 147 startguprof(p); 148 for (i = 0; i < CALIB_SCALE; i++) 149 cputime_overhead += cputime(); 150 151 empty_loop(); 152 startguprof(p); 153 empty_loop(); 154 empty_loop_time = cputime(); 155 156 nullfunc_loop_profiled(); 157 158 /* 159 * Start profiling. There won't be any normal function calls since 160 * interrupts are disabled, but we will call the profiling routines 161 * directly to determine their overheads. 162 */ 163 p->state = GMON_PROF_HIRES; 164 165 startguprof(p); 166 nullfunc_loop_profiled(); 167 168 startguprof(p); 169 for (i = 0; i < CALIB_SCALE; i++) 170 #if defined(__i386__) && __GNUC__ >= 2 171 __asm("pushl %0; call __mcount; popl %%ecx" 172 : 173 : "i" (profil) 174 : "ax", "bx", "cx", "dx", "memory"); 175 #else 176 #error 177 #endif 178 mcount_overhead = KCOUNT(p, PC_TO_I(p, profil)); 179 180 startguprof(p); 181 for (i = 0; i < CALIB_SCALE; i++) 182 #if defined(__i386__) && __GNUC__ >= 2 183 __asm("call " __XSTRING(HIDENAME(mexitcount)) "; 1:" 184 : : : "ax", "bx", "cx", "dx", "memory"); 185 __asm("movl $1b,%0" : "=rm" (tmp_addr)); 186 #else 187 #error 188 #endif 189 mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr)); 190 191 p->state = GMON_PROF_OFF; 192 stopguprof(p); 193 194 restore_intr(intrstate); 195 196 nullfunc_loop_profiled_time = 0; 197 for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled; 198 tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end; 199 tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER)) 200 nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr)); 201 #define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE) 202 #define c2n(count, freq) ((int)((count) * 1000000000LL / freq)) 203 printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n", 204 CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)), 205 CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)), 206 CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)), 207 CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)), 208 CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate))); 209 cputime_overhead -= empty_loop_time; 210 mcount_overhead -= empty_loop_time; 211 mexitcount_overhead -= empty_loop_time; 212 213 /*- 214 * Profiling overheads are determined by the times between the 215 * following events: 216 * MC1: mcount() is called 217 * MC2: cputime() (called from mcount()) latches the timer 218 * MC3: mcount() completes 219 * ME1: mexitcount() is called 220 * ME2: cputime() (called from mexitcount()) latches the timer 221 * ME3: mexitcount() completes. 222 * The times between the events vary slightly depending on instruction 223 * combination and cache misses, etc. Attempt to determine the 224 * minimum times. These can be subtracted from the profiling times 225 * without much risk of reducing the profiling times below what they 226 * would be when profiling is not configured. Abbreviate: 227 * ab = minimum time between MC1 and MC3 228 * a = minumum time between MC1 and MC2 229 * b = minimum time between MC2 and MC3 230 * cd = minimum time between ME1 and ME3 231 * c = minimum time between ME1 and ME2 232 * d = minimum time between ME2 and ME3. 233 * These satisfy the relations: 234 * ab <= mcount_overhead (just measured) 235 * a + b <= ab 236 * cd <= mexitcount_overhead (just measured) 237 * c + d <= cd 238 * a + d <= nullfunc_loop_profiled_time (just measured) 239 * a >= 0, b >= 0, c >= 0, d >= 0. 240 * Assume that ab and cd are equal to the minimums. 241 */ 242 p->cputime_overhead = CALIB_DOSCALE(cputime_overhead); 243 p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead); 244 p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead 245 - cputime_overhead); 246 nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time; 247 p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead 248 - nullfunc_loop_overhead) 249 / 4); 250 p->mexitcount_pre_overhead = p->mexitcount_overhead 251 + p->cputime_overhead 252 - p->mexitcount_post_overhead; 253 p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead) 254 - p->mexitcount_post_overhead; 255 p->mcount_post_overhead = p->mcount_overhead 256 + p->cputime_overhead 257 - p->mcount_pre_overhead; 258 printf( 259 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n", 260 c2n(p->cputime_overhead, p->profrate), 261 c2n(p->mcount_overhead, p->profrate), 262 c2n(p->mcount_pre_overhead, p->profrate), 263 c2n(p->mcount_post_overhead, p->profrate), 264 c2n(p->cputime_overhead, p->profrate), 265 c2n(p->mexitcount_overhead, p->profrate), 266 c2n(p->mexitcount_pre_overhead, p->profrate), 267 c2n(p->mexitcount_post_overhead, p->profrate)); 268 printf( 269 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n", 270 p->cputime_overhead, p->mcount_overhead, 271 p->mcount_pre_overhead, p->mcount_post_overhead, 272 p->cputime_overhead, p->mexitcount_overhead, 273 p->mexitcount_pre_overhead, p->mexitcount_post_overhead); 274 #endif /* GUPROF */ 275 } 276 277 /* 278 * Return kernel profiling information. 279 */ 280 static int 281 sysctl_kern_prof(SYSCTL_HANDLER_ARGS) 282 { 283 int *name = (int *) arg1; 284 u_int namelen = arg2; 285 struct gmonparam *gp = &_gmonparam; 286 int error; 287 int state; 288 289 /* all sysctl names at this level are terminal */ 290 if (namelen != 1) 291 return (ENOTDIR); /* overloaded */ 292 293 switch (name[0]) { 294 case GPROF_STATE: 295 state = gp->state; 296 error = sysctl_handle_int(oidp, &state, 0, req); 297 if (error) 298 return (error); 299 if (!req->newptr) 300 return (0); 301 if (state == GMON_PROF_OFF) { 302 gp->state = state; 303 stopprofclock(&proc0); 304 stopguprof(gp); 305 } else if (state == GMON_PROF_ON) { 306 gp->state = GMON_PROF_OFF; 307 stopguprof(gp); 308 gp->profrate = profhz; 309 startprofclock(&proc0); 310 gp->state = state; 311 #ifdef GUPROF 312 } else if (state == GMON_PROF_HIRES) { 313 gp->state = GMON_PROF_OFF; 314 stopprofclock(&proc0); 315 startguprof(gp); 316 gp->state = state; 317 #endif 318 } else if (state != gp->state) 319 return (EINVAL); 320 return (0); 321 case GPROF_COUNT: 322 return (sysctl_handle_opaque(oidp, 323 gp->kcount, gp->kcountsize, req)); 324 case GPROF_FROMS: 325 return (sysctl_handle_opaque(oidp, 326 gp->froms, gp->fromssize, req)); 327 case GPROF_TOS: 328 return (sysctl_handle_opaque(oidp, 329 gp->tos, gp->tossize, req)); 330 case GPROF_GMONPARAM: 331 return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req)); 332 default: 333 return (EOPNOTSUPP); 334 } 335 /* NOTREACHED */ 336 } 337 338 SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, ""); 339 #endif /* GPROF */ 340 341 /* 342 * Profiling system call. 343 * 344 * The scale factor is a fixed point number with 16 bits of fraction, so that 345 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. 346 */ 347 #ifndef _SYS_SYSPROTO_H_ 348 struct profil_args { 349 caddr_t samples; 350 size_t size; 351 size_t offset; 352 u_int scale; 353 }; 354 #endif 355 /* ARGSUSED */ 356 int 357 profil(p, uap) 358 struct proc *p; 359 register struct profil_args *uap; 360 { 361 register struct uprof *upp; 362 int s; 363 364 if (uap->scale > (1 << 16)) 365 return (EINVAL); 366 if (uap->scale == 0) { 367 stopprofclock(p); 368 return (0); 369 } 370 upp = &p->p_stats->p_prof; 371 372 /* Block profile interrupts while changing state. */ 373 s = splstatclock(); 374 upp->pr_off = uap->offset; 375 upp->pr_scale = uap->scale; 376 upp->pr_base = uap->samples; 377 upp->pr_size = uap->size; 378 startprofclock(p); 379 splx(s); 380 381 return (0); 382 } 383 384 /* 385 * Scale is a fixed-point number with the binary point 16 bits 386 * into the value, and is <= 1.0. pc is at most 32 bits, so the 387 * intermediate result is at most 48 bits. 388 */ 389 #define PC_TO_INDEX(pc, prof) \ 390 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 391 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 392 393 /* 394 * Collect user-level profiling statistics; called on a profiling tick, 395 * when a process is running in user-mode. This routine may be called 396 * from an interrupt context. We try to update the user profiling buffers 397 * cheaply with fuswintr() and suswintr(). If that fails, we revert to 398 * an AST that will vector us to trap() with a context in which copyin 399 * and copyout will work. Trap will then call addupc_task(). 400 * 401 * Note that we may (rarely) not get around to the AST soon enough, and 402 * lose profile ticks when the next tick overwrites this one, but in this 403 * case the system is overloaded and the profile is probably already 404 * inaccurate. 405 */ 406 void 407 addupc_intr(p, pc, ticks) 408 register struct proc *p; 409 register u_long pc; 410 u_int ticks; 411 { 412 register struct uprof *prof; 413 register caddr_t addr; 414 register u_int i; 415 register int v; 416 417 if (ticks == 0) 418 return; 419 prof = &p->p_stats->p_prof; 420 if (pc < prof->pr_off || 421 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 422 return; /* out of range; ignore */ 423 424 addr = prof->pr_base + i; 425 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) { 426 prof->pr_addr = pc; 427 prof->pr_ticks = ticks; 428 need_proftick(p); 429 } 430 } 431 432 /* 433 * Much like before, but we can afford to take faults here. If the 434 * update fails, we simply turn off profiling. 435 */ 436 void 437 addupc_task(p, pc, ticks) 438 register struct proc *p; 439 register u_long pc; 440 u_int ticks; 441 { 442 register struct uprof *prof; 443 register caddr_t addr; 444 register u_int i; 445 u_short v; 446 447 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */ 448 if ((p->p_flag & P_PROFIL) == 0 || ticks == 0) 449 return; 450 451 prof = &p->p_stats->p_prof; 452 if (pc < prof->pr_off || 453 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 454 return; 455 456 addr = prof->pr_base + i; 457 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) { 458 v += ticks; 459 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0) 460 return; 461 } 462 stopprofclock(p); 463 } 464