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/ipl.h> 41 #include <sys/kernel.h> 42 #include <sys/proc.h> 43 #include <sys/resourcevar.h> 44 #include <sys/sysctl.h> 45 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 int intrstate; 96 #endif 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 | M_ZERO); 118 if (cp == 0) { 119 printf("No memory for profiling.\n"); 120 return; 121 } 122 p->tos = (struct tostruct *)cp; 123 cp += p->tossize; 124 p->kcount = (HISTCOUNTER *)cp; 125 cp += p->kcountsize; 126 p->froms = (u_short *)cp; 127 128 #ifdef GUPROF 129 /* Initialize pointers to overhead counters. */ 130 p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime)); 131 p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount)); 132 p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount)); 133 134 /* 135 * Disable interrupts to avoid interference while we calibrate 136 * things. 137 */ 138 intrstate = save_intr(); 139 disable_intr(); 140 141 /* 142 * Determine overheads. 143 * XXX this needs to be repeated for each useful timer/counter. 144 */ 145 cputime_overhead = 0; 146 startguprof(p); 147 for (i = 0; i < CALIB_SCALE; i++) 148 cputime_overhead += cputime(); 149 150 empty_loop(); 151 startguprof(p); 152 empty_loop(); 153 empty_loop_time = cputime(); 154 155 nullfunc_loop_profiled(); 156 157 /* 158 * Start profiling. There won't be any normal function calls since 159 * interrupts are disabled, but we will call the profiling routines 160 * directly to determine their overheads. 161 */ 162 p->state = GMON_PROF_HIRES; 163 164 startguprof(p); 165 nullfunc_loop_profiled(); 166 167 startguprof(p); 168 for (i = 0; i < CALIB_SCALE; i++) 169 #if defined(__i386__) && __GNUC__ >= 2 170 __asm("pushl %0; call __mcount; popl %%ecx" 171 : 172 : "i" (profil) 173 : "ax", "bx", "cx", "dx", "memory"); 174 #else 175 #error 176 #endif 177 mcount_overhead = KCOUNT(p, PC_TO_I(p, profil)); 178 179 startguprof(p); 180 for (i = 0; i < CALIB_SCALE; i++) 181 #if defined(__i386__) && __GNUC__ >= 2 182 __asm("call " __XSTRING(HIDENAME(mexitcount)) "; 1:" 183 : : : "ax", "bx", "cx", "dx", "memory"); 184 __asm("movl $1b,%0" : "=rm" (tmp_addr)); 185 #else 186 #error 187 #endif 188 mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr)); 189 190 p->state = GMON_PROF_OFF; 191 stopguprof(p); 192 193 restore_intr(intrstate); 194 195 nullfunc_loop_profiled_time = 0; 196 for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled; 197 tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end; 198 tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER)) 199 nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr)); 200 #define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE) 201 #define c2n(count, freq) ((int)((count) * 1000000000LL / freq)) 202 printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n", 203 CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)), 204 CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)), 205 CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)), 206 CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)), 207 CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate))); 208 cputime_overhead -= empty_loop_time; 209 mcount_overhead -= empty_loop_time; 210 mexitcount_overhead -= empty_loop_time; 211 212 /*- 213 * Profiling overheads are determined by the times between the 214 * following events: 215 * MC1: mcount() is called 216 * MC2: cputime() (called from mcount()) latches the timer 217 * MC3: mcount() completes 218 * ME1: mexitcount() is called 219 * ME2: cputime() (called from mexitcount()) latches the timer 220 * ME3: mexitcount() completes. 221 * The times between the events vary slightly depending on instruction 222 * combination and cache misses, etc. Attempt to determine the 223 * minimum times. These can be subtracted from the profiling times 224 * without much risk of reducing the profiling times below what they 225 * would be when profiling is not configured. Abbreviate: 226 * ab = minimum time between MC1 and MC3 227 * a = minumum time between MC1 and MC2 228 * b = minimum time between MC2 and MC3 229 * cd = minimum time between ME1 and ME3 230 * c = minimum time between ME1 and ME2 231 * d = minimum time between ME2 and ME3. 232 * These satisfy the relations: 233 * ab <= mcount_overhead (just measured) 234 * a + b <= ab 235 * cd <= mexitcount_overhead (just measured) 236 * c + d <= cd 237 * a + d <= nullfunc_loop_profiled_time (just measured) 238 * a >= 0, b >= 0, c >= 0, d >= 0. 239 * Assume that ab and cd are equal to the minimums. 240 */ 241 p->cputime_overhead = CALIB_DOSCALE(cputime_overhead); 242 p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead); 243 p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead 244 - cputime_overhead); 245 nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time; 246 p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead 247 - nullfunc_loop_overhead) 248 / 4); 249 p->mexitcount_pre_overhead = p->mexitcount_overhead 250 + p->cputime_overhead 251 - p->mexitcount_post_overhead; 252 p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead) 253 - p->mexitcount_post_overhead; 254 p->mcount_post_overhead = p->mcount_overhead 255 + p->cputime_overhead 256 - p->mcount_pre_overhead; 257 printf( 258 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n", 259 c2n(p->cputime_overhead, p->profrate), 260 c2n(p->mcount_overhead, p->profrate), 261 c2n(p->mcount_pre_overhead, p->profrate), 262 c2n(p->mcount_post_overhead, p->profrate), 263 c2n(p->cputime_overhead, p->profrate), 264 c2n(p->mexitcount_overhead, p->profrate), 265 c2n(p->mexitcount_pre_overhead, p->profrate), 266 c2n(p->mexitcount_post_overhead, p->profrate)); 267 printf( 268 "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n", 269 p->cputime_overhead, p->mcount_overhead, 270 p->mcount_pre_overhead, p->mcount_post_overhead, 271 p->cputime_overhead, p->mexitcount_overhead, 272 p->mexitcount_pre_overhead, p->mexitcount_post_overhead); 273 #endif /* GUPROF */ 274 } 275 276 /* 277 * Return kernel profiling information. 278 */ 279 static int 280 sysctl_kern_prof(SYSCTL_HANDLER_ARGS) 281 { 282 int *name = (int *) arg1; 283 u_int namelen = arg2; 284 struct gmonparam *gp = &_gmonparam; 285 int error; 286 int state; 287 288 /* all sysctl names at this level are terminal */ 289 if (namelen != 1) 290 return (ENOTDIR); /* overloaded */ 291 292 switch (name[0]) { 293 case GPROF_STATE: 294 state = gp->state; 295 error = sysctl_handle_int(oidp, &state, 0, req); 296 if (error) 297 return (error); 298 if (!req->newptr) 299 return (0); 300 if (state == GMON_PROF_OFF) { 301 gp->state = state; 302 stopprofclock(&proc0); 303 stopguprof(gp); 304 } else if (state == GMON_PROF_ON) { 305 gp->state = GMON_PROF_OFF; 306 stopguprof(gp); 307 gp->profrate = profhz; 308 startprofclock(&proc0); 309 gp->state = state; 310 #ifdef GUPROF 311 } else if (state == GMON_PROF_HIRES) { 312 gp->state = GMON_PROF_OFF; 313 stopprofclock(&proc0); 314 startguprof(gp); 315 gp->state = state; 316 #endif 317 } else if (state != gp->state) 318 return (EINVAL); 319 return (0); 320 case GPROF_COUNT: 321 return (sysctl_handle_opaque(oidp, 322 gp->kcount, gp->kcountsize, req)); 323 case GPROF_FROMS: 324 return (sysctl_handle_opaque(oidp, 325 gp->froms, gp->fromssize, req)); 326 case GPROF_TOS: 327 return (sysctl_handle_opaque(oidp, 328 gp->tos, gp->tossize, req)); 329 case GPROF_GMONPARAM: 330 return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req)); 331 default: 332 return (EOPNOTSUPP); 333 } 334 /* NOTREACHED */ 335 } 336 337 SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, ""); 338 #endif /* GPROF */ 339 340 /* 341 * Profiling system call. 342 * 343 * The scale factor is a fixed point number with 16 bits of fraction, so that 344 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. 345 */ 346 #ifndef _SYS_SYSPROTO_H_ 347 struct profil_args { 348 caddr_t samples; 349 size_t size; 350 size_t offset; 351 u_int scale; 352 }; 353 #endif 354 /* ARGSUSED */ 355 int 356 profil(p, uap) 357 struct proc *p; 358 register struct profil_args *uap; 359 { 360 register struct uprof *upp; 361 int s; 362 363 if (uap->scale > (1 << 16)) 364 return (EINVAL); 365 if (uap->scale == 0) { 366 stopprofclock(p); 367 return (0); 368 } 369 upp = &p->p_stats->p_prof; 370 371 /* Block profile interrupts while changing state. */ 372 s = splstatclock(); 373 upp->pr_off = uap->offset; 374 upp->pr_scale = uap->scale; 375 upp->pr_base = uap->samples; 376 upp->pr_size = uap->size; 377 startprofclock(p); 378 splx(s); 379 380 return (0); 381 } 382 383 /* 384 * Scale is a fixed-point number with the binary point 16 bits 385 * into the value, and is <= 1.0. pc is at most 32 bits, so the 386 * intermediate result is at most 48 bits. 387 */ 388 #define PC_TO_INDEX(pc, prof) \ 389 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 390 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 391 392 /* 393 * Collect user-level profiling statistics; called on a profiling tick, 394 * when a process is running in user-mode. This routine may be called 395 * from an interrupt context. We try to update the user profiling buffers 396 * cheaply with fuswintr() and suswintr(). If that fails, we revert to 397 * an AST that will vector us to trap() with a context in which copyin 398 * and copyout will work. Trap will then call addupc_task(). 399 * 400 * Note that we may (rarely) not get around to the AST soon enough, and 401 * lose profile ticks when the next tick overwrites this one, but in this 402 * case the system is overloaded and the profile is probably already 403 * inaccurate. 404 */ 405 void 406 addupc_intr(p, pc, ticks) 407 register struct proc *p; 408 register u_long pc; 409 u_int ticks; 410 { 411 register struct uprof *prof; 412 register caddr_t addr; 413 register u_int i; 414 register int v; 415 416 if (ticks == 0) 417 return; 418 prof = &p->p_stats->p_prof; 419 if (pc < prof->pr_off || 420 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 421 return; /* out of range; ignore */ 422 423 addr = prof->pr_base + i; 424 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) { 425 prof->pr_addr = pc; 426 prof->pr_ticks = ticks; 427 need_proftick(p); 428 } 429 } 430 431 /* 432 * Much like before, but we can afford to take faults here. If the 433 * update fails, we simply turn off profiling. 434 */ 435 void 436 addupc_task(p, pc, ticks) 437 register struct proc *p; 438 register u_long pc; 439 u_int ticks; 440 { 441 register struct uprof *prof; 442 register caddr_t addr; 443 register u_int i; 444 u_short v; 445 446 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */ 447 if ((p->p_flag & P_PROFIL) == 0 || ticks == 0) 448 return; 449 450 prof = &p->p_stats->p_prof; 451 if (pc < prof->pr_off || 452 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 453 return; 454 455 addr = prof->pr_base + i; 456 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) { 457 v += ticks; 458 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0) 459 return; 460 } 461 stopprofclock(p); 462 } 463