154 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/* Copyright (c) 2016 Facebook3 */4#include <stdio.h>5#include <unistd.h>6#include <stdlib.h>7#include <signal.h>8#include <linux/perf_event.h>9#include <errno.h>10#include <stdbool.h>11#include <bpf/libbpf.h>12#include <bpf/bpf.h>13#include "trace_helpers.h"14 15#define PRINT_RAW_ADDR 016 17/* counts, stackmap */18static int map_fd[2];19 20static void print_ksym(__u64 addr)21{22 struct ksym *sym;23 24 if (!addr)25 return;26 sym = ksym_search(addr);27 if (!sym) {28 printf("ksym not found. Is kallsyms loaded?\n");29 return;30 }31 32 if (PRINT_RAW_ADDR)33 printf("%s/%llx;", sym->name, addr);34 else35 printf("%s;", sym->name);36}37 38#define TASK_COMM_LEN 1639 40struct key_t {41 char waker[TASK_COMM_LEN];42 char target[TASK_COMM_LEN];43 __u32 wret;44 __u32 tret;45};46 47static void print_stack(struct key_t *key, __u64 count)48{49 __u64 ip[PERF_MAX_STACK_DEPTH] = {};50 static bool warned;51 int i;52 53 printf("%s;", key->target);54 if (bpf_map_lookup_elem(map_fd[1], &key->tret, ip) != 0) {55 printf("---;");56 } else {57 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)58 print_ksym(ip[i]);59 }60 printf("-;");61 if (bpf_map_lookup_elem(map_fd[1], &key->wret, ip) != 0) {62 printf("---;");63 } else {64 for (i = 0; i < PERF_MAX_STACK_DEPTH; i++)65 print_ksym(ip[i]);66 }67 printf(";%s %lld\n", key->waker, count);68 69 if ((key->tret == -EEXIST || key->wret == -EEXIST) && !warned) {70 printf("stackmap collisions seen. Consider increasing size\n");71 warned = true;72 } else if (((int)(key->tret) < 0 || (int)(key->wret) < 0)) {73 printf("err stackid %d %d\n", key->tret, key->wret);74 }75}76 77static void print_stacks(int fd)78{79 struct key_t key = {}, next_key;80 __u64 value;81 82 while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {83 bpf_map_lookup_elem(fd, &next_key, &value);84 print_stack(&next_key, value);85 key = next_key;86 }87}88 89static void int_exit(int sig)90{91 print_stacks(map_fd[0]);92 exit(0);93}94 95int main(int argc, char **argv)96{97 struct bpf_object *obj = NULL;98 struct bpf_link *links[2];99 struct bpf_program *prog;100 int delay = 1, i = 0;101 char filename[256];102 103 if (load_kallsyms()) {104 printf("failed to process /proc/kallsyms\n");105 return 2;106 }107 108 snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]);109 obj = bpf_object__open_file(filename, NULL);110 if (libbpf_get_error(obj)) {111 fprintf(stderr, "ERROR: opening BPF object file failed\n");112 obj = NULL;113 goto cleanup;114 }115 116 /* load BPF program */117 if (bpf_object__load(obj)) {118 fprintf(stderr, "ERROR: loading BPF object file failed\n");119 goto cleanup;120 }121 122 map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");123 map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");124 if (map_fd[0] < 0 || map_fd[1] < 0) {125 fprintf(stderr, "ERROR: finding a map in obj file failed\n");126 goto cleanup;127 }128 129 signal(SIGINT, int_exit);130 signal(SIGTERM, int_exit);131 132 bpf_object__for_each_program(prog, obj) {133 links[i] = bpf_program__attach(prog);134 if (libbpf_get_error(links[i])) {135 fprintf(stderr, "ERROR: bpf_program__attach failed\n");136 links[i] = NULL;137 goto cleanup;138 }139 i++;140 }141 142 if (argc > 1)143 delay = atoi(argv[1]);144 sleep(delay);145 print_stacks(map_fd[0]);146 147cleanup:148 for (i--; i >= 0; i--)149 bpf_link__destroy(links[i]);150 151 bpf_object__close(obj);152 return 0;153}154