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tprof_analyze.c revision 1.2 
      1 /*	$NetBSD: tprof_analyze.c,v 1.2 2018/07/13 12:04:50 maxv Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2010,2011,2012 YAMAMOTO Takashi,
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 #ifndef lint
     31 __RCSID("$NetBSD: tprof_analyze.c,v 1.2 2018/07/13 12:04:50 maxv Exp $");
     32 #endif /* not lint */
     33 
     34 #include <assert.h>
     35 #include <err.h>
     36 #include <errno.h>
     37 #include <fcntl.h>
     38 #include <gelf.h>
     39 #include <inttypes.h>
     40 #include <libelf.h>
     41 #include <stdbool.h>
     42 #include <stdlib.h>
     43 #include <stdio.h>
     44 #include <unistd.h>
     45 #include <string.h>
     46 #include <util.h>
     47 #include <dev/tprof/tprof_ioctl.h>
     48 #include "tprof.h"
     49 
     50 #define	_PATH_KSYMS	"/dev/ksyms"
     51 
     52 #include <sys/rbtree.h>
     53 
     54 static bool filter_by_pid;
     55 static pid_t target_pid;
     56 static bool per_symbol;
     57 
     58 struct addr {
     59 	struct rb_node node;
     60 	uint64_t addr;		/* address */
     61 	uint32_t pid;		/* process id */
     62 	uint32_t lwpid;		/* lwp id */
     63 	uint32_t cpuid;		/* cpu id */
     64 	bool in_kernel;		/* if addr is in the kernel address space */
     65 	unsigned int nsamples;	/* number of samples taken for the address */
     66 };
     67 
     68 static rb_tree_t addrtree;
     69 
     70 struct sym {
     71 	char *name;
     72 	uint64_t value;
     73 	uint64_t size;
     74 };
     75 
     76 static struct sym **syms = NULL;
     77 static size_t nsyms = 0;
     78 
     79 static int
     80 compare_value(const void *p1, const void *p2)
     81 {
     82 	const struct sym *s1 = *(const struct sym * const *)p1;
     83 	const struct sym *s2 = *(const struct sym * const *)p2;
     84 
     85 	if (s1->value > s2->value) {
     86 		return -1;
     87 	} else if (s1->value < s2->value) {
     88 		return 1;
     89 	}
     90 	/*
     91 	 * to produce a stable result, it's better not to return 0
     92 	 * even for __strong_alias.
     93 	 */
     94 	if (s1->size > s2->size) {
     95 		return -1;
     96 	} else if (s1->size < s2->size) {
     97 		return 1;
     98 	}
     99 	return strcmp(s1->name, s2->name);
    100 }
    101 
    102 static void
    103 ksymload(void)
    104 {
    105 	Elf *e;
    106 	Elf_Scn *s;
    107 	GElf_Shdr sh_store;
    108 	GElf_Shdr *sh;
    109 	Elf_Data *d;
    110 	int fd;
    111 	size_t size, i;
    112 
    113 	fd = open(_PATH_KSYMS, O_RDONLY);
    114 	if (fd == -1) {
    115 		err(EXIT_FAILURE, "open");
    116 	}
    117 	if (elf_version(EV_CURRENT) == EV_NONE) {
    118 		goto elffail;
    119 	}
    120 	e = elf_begin(fd, ELF_C_READ, NULL);
    121 	if (e == NULL) {
    122 		goto elffail;
    123 	}
    124 	for (s = elf_nextscn(e, NULL); s != NULL; s = elf_nextscn(e, s)) {
    125 		sh = gelf_getshdr(s, &sh_store);
    126 		if (sh == NULL) {
    127 			goto elffail;
    128 		}
    129 		if (sh->sh_type == SHT_SYMTAB) {
    130 			break;
    131 		}
    132 	}
    133 	if (s == NULL) {
    134 		errx(EXIT_FAILURE, "no symtab");
    135 	}
    136 	d = elf_getdata(s, NULL);
    137 	if (d == NULL) {
    138 		goto elffail;
    139 	}
    140 	assert(sh->sh_size == d->d_size);
    141 	size = sh->sh_size / sh->sh_entsize;
    142 	for (i = 1; i < size; i++) {
    143 		GElf_Sym st_store;
    144 		GElf_Sym *st;
    145 		struct sym *sym;
    146 
    147 		st = gelf_getsym(d, (int)i, &st_store);
    148 		if (st == NULL) {
    149 			goto elffail;
    150 		}
    151 		if (ELF_ST_TYPE(st->st_info) != STT_FUNC) {
    152 			continue;
    153 		}
    154 		sym = emalloc(sizeof(*sym));
    155 		sym->name = estrdup(elf_strptr(e, sh->sh_link, st->st_name));
    156 		sym->value = (uint64_t)st->st_value;
    157 		sym->size = st->st_size;
    158 		nsyms++;
    159 		syms = erealloc(syms, sizeof(*syms) * nsyms);
    160 		syms[nsyms - 1] = sym;
    161 	}
    162 	qsort(syms, nsyms, sizeof(*syms), compare_value);
    163 	return;
    164 elffail:
    165 	errx(EXIT_FAILURE, "libelf: %s", elf_errmsg(elf_errno()));
    166 }
    167 
    168 static const char *
    169 ksymlookup(uint64_t value, uint64_t *offset)
    170 {
    171 	size_t hi;
    172 	size_t lo;
    173 	size_t i;
    174 
    175 	/*
    176 	 * try to find the smallest i for which syms[i]->value <= value.
    177 	 * syms[] is ordered by syms[]->value in the descending order.
    178 	 */
    179 
    180 	hi = nsyms - 1;
    181 	lo = 0;
    182 	while (lo < hi) {
    183 		const size_t mid = (lo + hi) / 2;
    184 		const struct sym *sym = syms[mid];
    185 
    186 		assert(syms[lo]->value >= sym->value);
    187 		assert(sym->value >= syms[hi]->value);
    188 		if (sym->value <= value) {
    189 			hi = mid;
    190 			continue;
    191 		}
    192 		lo = mid + 1;
    193 	}
    194 	assert(lo == nsyms - 1 || syms[lo]->value <= value);
    195 	assert(lo == 0 || syms[lo - 1]->value > value);
    196 	for (i = lo; i < nsyms; i++) {
    197 		const struct sym *sym = syms[i];
    198 
    199 		if (sym->value <= value &&
    200 		    (sym->size == 0 || value - sym->value <= sym->size )) {
    201 			*offset = value - sym->value;
    202 			return sym->name;
    203 		}
    204 		if (sym->size != 0 && sym->value + sym->size < value) {
    205 			break;
    206 		}
    207 	}
    208 	return NULL;
    209 }
    210 
    211 static signed int
    212 addrtree_compare_key(void *ctx, const void *n1, const void *keyp)
    213 {
    214 	const struct addr *a1 = n1;
    215 	const struct addr *a2 = (const struct addr *)keyp;
    216 
    217 	if (a1->addr > a2->addr) {
    218 		return 1;
    219 	} else if (a1->addr < a2->addr) {
    220 		return -1;
    221 	}
    222 	if (a1->pid > a2->pid) {
    223 		return -1;
    224 	} else if (a1->pid < a2->pid) {
    225 		return 1;
    226 	}
    227 	if (a1->lwpid > a2->lwpid) {
    228 		return -1;
    229 	} else if (a1->lwpid < a2->lwpid) {
    230 		return 1;
    231 	}
    232 	if (a1->cpuid > a2->cpuid) {
    233 		return -1;
    234 	} else if (a1->cpuid < a2->cpuid) {
    235 		return 1;
    236 	}
    237 	if (a1->in_kernel > a2->in_kernel) {
    238 		return -1;
    239 	} else if (a1->in_kernel < a2->in_kernel) {
    240 		return 1;
    241 	}
    242 	return 0;
    243 }
    244 
    245 static signed int
    246 addrtree_compare_nodes(void *ctx, const void *n1, const void *n2)
    247 {
    248 	const struct addr *a2 = n2;
    249 
    250 	return addrtree_compare_key(ctx, n1, a2);
    251 }
    252 
    253 static const rb_tree_ops_t addrtree_ops = {
    254 	.rbto_compare_nodes = addrtree_compare_nodes,
    255 	.rbto_compare_key = addrtree_compare_key,
    256 };
    257 
    258 static int
    259 compare_nsamples(const void *p1, const void *p2)
    260 {
    261 	const struct addr *a1 = *(const struct addr * const *)p1;
    262 	const struct addr *a2 = *(const struct addr * const *)p2;
    263 
    264 	if (a1->nsamples > a2->nsamples) {
    265 		return -1;
    266 	} else if (a1->nsamples < a2->nsamples) {
    267 		return 1;
    268 	}
    269 	return 0;
    270 }
    271 
    272 void
    273 tprof_analyze(int argc, char **argv)
    274 {
    275 	struct addr *a;
    276 	struct addr **l;
    277 	struct addr **p;
    278 	size_t naddrs, i;
    279 	int ch;
    280 	bool distinguish_processes = true;
    281 	bool distinguish_cpus = true;
    282 	bool distinguish_lwps = true;
    283 	bool kernel_only = false;
    284 	extern char *optarg;
    285 	extern int optind;
    286 	FILE *f;
    287 
    288 	while ((ch = getopt(argc, argv, "CkLPp:s")) != -1) {
    289 		uintmax_t val;
    290 		char *ep;
    291 
    292 		switch (ch) {
    293 		case 'C':	/* don't distinguish cpus */
    294 			distinguish_cpus = false;
    295 			break;
    296 		case 'k':	/* kernel only */
    297 			kernel_only = true;
    298 			break;
    299 		case 'L':	/* don't distinguish lwps */
    300 			distinguish_lwps = false;
    301 			break;
    302 		case 'p':	/* only for the process for the given pid */
    303 			errno = 0;
    304 			val = strtoumax(optarg, &ep, 10);
    305 			if (optarg[0] == 0 || *ep != 0 ||
    306 			    val > INT32_MAX) {
    307 				errx(EXIT_FAILURE, "invalid p option");
    308 			}
    309 			target_pid = val;
    310 			filter_by_pid = true;
    311 			break;
    312 		case 'P':	/* don't distinguish processes */
    313 			distinguish_processes = false;
    314 			break;
    315 		case 's':	/* per symbol */
    316 			per_symbol = true;
    317 			break;
    318 		default:
    319 			exit(EXIT_FAILURE);
    320 		}
    321 	}
    322 	argc -= optind;
    323 	argv += optind;
    324 
    325 	if (argc == 0) {
    326 		errx(EXIT_FAILURE, "missing file name");
    327 	}
    328 
    329 	f = fopen(argv[0], "rb");
    330 	if (f == NULL) {
    331 		errx(EXIT_FAILURE, "fopen");
    332 	}
    333 
    334 	ksymload();
    335 	rb_tree_init(&addrtree, &addrtree_ops);
    336 
    337 	/*
    338 	 * read and count samples.
    339 	 */
    340 
    341 	naddrs = 0;
    342 	while (/*CONSTCOND*/true) {
    343 		struct addr *o;
    344 		tprof_sample_t sample;
    345 		size_t n = fread(&sample, sizeof(sample), 1, f);
    346 		bool in_kernel;
    347 
    348 		if (n == 0) {
    349 			if (feof(f)) {
    350 				break;
    351 			}
    352 			if (ferror(f)) {
    353 				err(EXIT_FAILURE, "fread");
    354 			}
    355 		}
    356 		if (filter_by_pid && (pid_t)sample.s_pid != target_pid) {
    357 			continue;
    358 		}
    359 		in_kernel = (sample.s_flags & TPROF_SAMPLE_INKERNEL) != 0;
    360 		if (kernel_only && !in_kernel) {
    361 			continue;
    362 		}
    363 		a = emalloc(sizeof(*a));
    364 		a->addr = (uint64_t)sample.s_pc;
    365 		if (distinguish_processes) {
    366 			a->pid = sample.s_pid;
    367 		} else {
    368 			a->pid = 0;
    369 		}
    370 		if (distinguish_lwps) {
    371 			a->lwpid = sample.s_lwpid;
    372 		} else {
    373 			a->lwpid = 0;
    374 		}
    375 		if (distinguish_cpus) {
    376 			a->cpuid = sample.s_cpuid;
    377 		} else {
    378 			a->cpuid = 0;
    379 		}
    380 		a->in_kernel = in_kernel;
    381 		if (per_symbol) {
    382 			const char *name;
    383 			uint64_t offset;
    384 
    385 			name = ksymlookup(a->addr, &offset);
    386 			if (name != NULL) {
    387 				a->addr -= offset;
    388 			}
    389 		}
    390 		a->nsamples = 1;
    391 		o = rb_tree_insert_node(&addrtree, a);
    392 		if (o != a) {
    393 			assert(a->addr == o->addr);
    394 			assert(a->pid == o->pid);
    395 			assert(a->lwpid == o->lwpid);
    396 			assert(a->cpuid == o->cpuid);
    397 			assert(a->in_kernel == o->in_kernel);
    398 			free(a);
    399 			o->nsamples++;
    400 		} else {
    401 			naddrs++;
    402 		}
    403 	}
    404 
    405 	/*
    406 	 * sort samples by addresses.
    407 	 */
    408 
    409 	l = emalloc(naddrs * sizeof(*l));
    410 	p = l;
    411 	RB_TREE_FOREACH(a, &addrtree) {
    412 		*p++ = a;
    413 	}
    414 	assert(l + naddrs == p);
    415 	qsort(l, naddrs, sizeof(*l), compare_nsamples);
    416 
    417 	/*
    418 	 * print addresses and number of samples, preferably with
    419 	 * resolved symbol names.
    420 	 */
    421 
    422 	for (i = 0; i < naddrs; i++) {
    423 		const char *name;
    424 		char buf[100];
    425 		uint64_t offset;
    426 
    427 		a = l[i];
    428 		if (a->in_kernel) {
    429 			name = ksymlookup(a->addr, &offset);
    430 		} else {
    431 			name = NULL;
    432 		}
    433 		if (name == NULL) {
    434 			(void)snprintf(buf, sizeof(buf), "<%016" PRIx64 ">",
    435 			    a->addr);
    436 			name = buf;
    437 		} else if (offset != 0) {
    438 			(void)snprintf(buf, sizeof(buf), "%s+0x%" PRIx64, name,
    439 			    offset);
    440 			name = buf;
    441 		}
    442 		printf("%8u %6" PRIu32 " %4" PRIu32 " %2" PRIu32 " %u %016"
    443 		    PRIx64 " %s\n",
    444 		    a->nsamples, a->pid, a->lwpid, a->cpuid, a->in_kernel,
    445 		    a->addr, name);
    446 	}
    447 
    448 	fclose(f);
    449 }
    450