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: src/sys/kern/subr_prof.c,v 1.32.2.2 2000/08/03 00:09:32 ps Exp $ 35 * $DragonFly: src/sys/kern/subr_prof.c,v 1.10 2005/06/06 15:02:28 dillon Exp $ 36 */ 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/sysproto.h> 41 #include <sys/kernel.h> 42 #include <sys/proc.h> 43 #include <sys/resourcevar.h> 44 #include <sys/sysctl.h> 45 #include <sys/thread2.h> 46 47 #include <machine/ipl.h> 48 #include <machine/cpu.h> 49 50 #ifdef GPROF 51 #include <sys/malloc.h> 52 #include <sys/gmon.h> 53 #undef MCOUNT 54 55 static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer"); 56 57 static void kmstartup (void *); 58 SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL) 59 60 struct gmonparam _gmonparam = { GMON_PROF_OFF }; 61 62 #ifdef GUPROF 63 #include <machine/asmacros.h> 64 65 void 66 nullfunc_loop_profiled() 67 { 68 int i; 69 70 for (i = 0; i < CALIB_SCALE; i++) 71 nullfunc_profiled(); 72 } 73 74 #define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */ 75 76 void 77 nullfunc_profiled() 78 { 79 } 80 #endif /* GUPROF */ 81 82 static void 83 kmstartup(void *dummy) 84 { 85 char *cp; 86 struct gmonparam *p = &_gmonparam; 87 #ifdef GUPROF 88 int cputime_overhead; 89 int empty_loop_time; 90 int i; 91 int mcount_overhead; 92 int mexitcount_overhead; 93 int nullfunc_loop_overhead; 94 int nullfunc_loop_profiled_time; 95 uintfptr_t tmp_addr; 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); 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 cpu_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 cpu_enable_intr(); 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 /* ARGSUSED */ 347 int 348 profil(struct profil_args *uap) 349 { 350 struct proc *p = curproc; 351 struct uprof *upp; 352 353 if (uap->scale > (1 << 16)) 354 return (EINVAL); 355 if (uap->scale == 0) { 356 stopprofclock(p); 357 return (0); 358 } 359 upp = &p->p_stats->p_prof; 360 361 /* Block profile interrupts while changing state. */ 362 crit_enter(); 363 upp->pr_off = uap->offset; 364 upp->pr_scale = uap->scale; 365 upp->pr_base = uap->samples; 366 upp->pr_size = uap->size; 367 startprofclock(p); 368 crit_exit(); 369 370 return (0); 371 } 372 373 /* 374 * Scale is a fixed-point number with the binary point 16 bits 375 * into the value, and is <= 1.0. pc is at most 32 bits, so the 376 * intermediate result is at most 48 bits. 377 */ 378 #define PC_TO_INDEX(pc, prof) \ 379 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 380 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 381 382 /* 383 * Collect user-level profiling statistics; called on a profiling tick, 384 * when a process is running in user-mode. This routine may be called 385 * from an interrupt context. We try to update the user profiling buffers 386 * cheaply with fuswintr() and suswintr(). If that fails, we revert to 387 * an AST that will vector us to trap() with a context in which copyin 388 * and copyout will work. Trap will then call addupc_task(). 389 * 390 * Note that we may (rarely) not get around to the AST soon enough, and 391 * lose profile ticks when the next tick overwrites this one, but in this 392 * case the system is overloaded and the profile is probably already 393 * inaccurate. 394 */ 395 void 396 addupc_intr(struct proc *p, u_long pc, u_int ticks) 397 { 398 struct uprof *prof; 399 caddr_t addr; 400 u_int i; 401 int v; 402 403 if (ticks == 0) 404 return; 405 prof = &p->p_stats->p_prof; 406 if (pc < prof->pr_off || 407 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 408 return; /* out of range; ignore */ 409 410 addr = prof->pr_base + i; 411 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) { 412 prof->pr_addr = pc; 413 prof->pr_ticks = ticks; 414 need_proftick(); 415 } 416 } 417 418 /* 419 * Much like before, but we can afford to take faults here. If the 420 * update fails, we simply turn off profiling. 421 */ 422 void 423 addupc_task(struct proc *p, u_long pc, u_int ticks) 424 { 425 struct uprof *prof; 426 caddr_t addr; 427 u_int i; 428 u_short v; 429 430 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */ 431 if ((p->p_flag & P_PROFIL) == 0 || ticks == 0) 432 return; 433 434 prof = &p->p_stats->p_prof; 435 if (pc < prof->pr_off || 436 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 437 return; 438 439 addr = prof->pr_base + i; 440 if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) { 441 v += ticks; 442 if (copyout((caddr_t)&v, addr, sizeof(v)) == 0) 443 return; 444 } 445 stopprofclock(p); 446 } 447