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25763b3c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
72874418 BG |
2 | /* |
3 | * sampleip: sample instruction pointer and frequency count in a BPF map. | |
4 | * | |
5 | * Copyright 2016 Netflix, Inc. | |
72874418 BG |
6 | */ |
7 | #include <stdio.h> | |
8 | #include <stdlib.h> | |
72874418 BG |
9 | #include <unistd.h> |
10 | #include <errno.h> | |
11 | #include <signal.h> | |
12 | #include <string.h> | |
72874418 BG |
13 | #include <linux/perf_event.h> |
14 | #include <linux/ptrace.h> | |
15 | #include <linux/bpf.h> | |
aa5e2af6 | 16 | #include <bpf/bpf.h> |
7cf245a3 | 17 | #include <bpf/libbpf.h> |
205c8ada | 18 | #include "perf-sys.h" |
28dbf861 | 19 | #include "trace_helpers.h" |
72874418 BG |
20 | |
21 | #define DEFAULT_FREQ 99 | |
22 | #define DEFAULT_SECS 5 | |
23 | #define MAX_IPS 8192 | |
24 | #define PAGE_OFFSET 0xffff880000000000 | |
25 | ||
aa5e2af6 | 26 | static int map_fd; |
72874418 BG |
27 | static int nr_cpus; |
28 | ||
29 | static void usage(void) | |
30 | { | |
31 | printf("USAGE: sampleip [-F freq] [duration]\n"); | |
32 | printf(" -F freq # sample frequency (Hertz), default 99\n"); | |
33 | printf(" duration # sampling duration (seconds), default 5\n"); | |
34 | } | |
35 | ||
aa5e2af6 DL |
36 | static int sampling_start(int freq, struct bpf_program *prog, |
37 | struct bpf_link *links[]) | |
72874418 | 38 | { |
aa5e2af6 | 39 | int i, pmu_fd; |
72874418 BG |
40 | |
41 | struct perf_event_attr pe_sample_attr = { | |
42 | .type = PERF_TYPE_SOFTWARE, | |
43 | .freq = 1, | |
44 | .sample_period = freq, | |
45 | .config = PERF_COUNT_SW_CPU_CLOCK, | |
46 | .inherit = 1, | |
47 | }; | |
48 | ||
49 | for (i = 0; i < nr_cpus; i++) { | |
aa5e2af6 | 50 | pmu_fd = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i, |
72874418 | 51 | -1 /* group_fd */, 0 /* flags */); |
aa5e2af6 | 52 | if (pmu_fd < 0) { |
72874418 BG |
53 | fprintf(stderr, "ERROR: Initializing perf sampling\n"); |
54 | return 1; | |
55 | } | |
aa5e2af6 | 56 | links[i] = bpf_program__attach_perf_event(prog, pmu_fd); |
0efdcefb | 57 | if (libbpf_get_error(links[i])) { |
aa5e2af6 DL |
58 | fprintf(stderr, "ERROR: Attach perf event\n"); |
59 | links[i] = NULL; | |
60 | close(pmu_fd); | |
61 | return 1; | |
62 | } | |
72874418 BG |
63 | } |
64 | ||
65 | return 0; | |
66 | } | |
67 | ||
aa5e2af6 | 68 | static void sampling_end(struct bpf_link *links[]) |
72874418 BG |
69 | { |
70 | int i; | |
71 | ||
72 | for (i = 0; i < nr_cpus; i++) | |
aa5e2af6 | 73 | bpf_link__destroy(links[i]); |
72874418 BG |
74 | } |
75 | ||
76 | struct ipcount { | |
77 | __u64 ip; | |
78 | __u32 count; | |
79 | }; | |
80 | ||
81 | /* used for sorting */ | |
82 | struct ipcount counts[MAX_IPS]; | |
83 | ||
84 | static int count_cmp(const void *p1, const void *p2) | |
85 | { | |
86 | return ((struct ipcount *)p1)->count - ((struct ipcount *)p2)->count; | |
87 | } | |
88 | ||
89 | static void print_ip_map(int fd) | |
90 | { | |
91 | struct ksym *sym; | |
92 | __u64 key, next_key; | |
93 | __u32 value; | |
94 | int i, max; | |
95 | ||
96 | printf("%-19s %-32s %s\n", "ADDR", "KSYM", "COUNT"); | |
97 | ||
98 | /* fetch IPs and counts */ | |
99 | key = 0, i = 0; | |
d40fc181 JS |
100 | while (bpf_map_get_next_key(fd, &key, &next_key) == 0) { |
101 | bpf_map_lookup_elem(fd, &next_key, &value); | |
72874418 BG |
102 | counts[i].ip = next_key; |
103 | counts[i++].count = value; | |
104 | key = next_key; | |
105 | } | |
106 | max = i; | |
107 | ||
108 | /* sort and print */ | |
109 | qsort(counts, max, sizeof(struct ipcount), count_cmp); | |
110 | for (i = 0; i < max; i++) { | |
111 | if (counts[i].ip > PAGE_OFFSET) { | |
112 | sym = ksym_search(counts[i].ip); | |
e67b2c71 DL |
113 | if (!sym) { |
114 | printf("ksym not found. Is kallsyms loaded?\n"); | |
115 | continue; | |
116 | } | |
117 | ||
72874418 BG |
118 | printf("0x%-17llx %-32s %u\n", counts[i].ip, sym->name, |
119 | counts[i].count); | |
120 | } else { | |
121 | printf("0x%-17llx %-32s %u\n", counts[i].ip, "(user)", | |
122 | counts[i].count); | |
123 | } | |
124 | } | |
125 | ||
126 | if (max == MAX_IPS) { | |
127 | printf("WARNING: IP hash was full (max %d entries); ", max); | |
128 | printf("may have dropped samples\n"); | |
129 | } | |
130 | } | |
131 | ||
132 | static void int_exit(int sig) | |
133 | { | |
134 | printf("\n"); | |
aa5e2af6 | 135 | print_ip_map(map_fd); |
72874418 BG |
136 | exit(0); |
137 | } | |
138 | ||
139 | int main(int argc, char **argv) | |
140 | { | |
aa5e2af6 DL |
141 | int opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS, error = 1; |
142 | struct bpf_object *obj = NULL; | |
143 | struct bpf_program *prog; | |
144 | struct bpf_link **links; | |
72874418 | 145 | char filename[256]; |
72874418 BG |
146 | |
147 | /* process arguments */ | |
148 | while ((opt = getopt(argc, argv, "F:h")) != -1) { | |
149 | switch (opt) { | |
150 | case 'F': | |
151 | freq = atoi(optarg); | |
152 | break; | |
153 | case 'h': | |
154 | default: | |
155 | usage(); | |
156 | return 0; | |
157 | } | |
158 | } | |
159 | if (argc - optind == 1) | |
160 | secs = atoi(argv[optind]); | |
161 | if (freq == 0 || secs == 0) { | |
162 | usage(); | |
163 | return 1; | |
164 | } | |
165 | ||
166 | /* initialize kernel symbol translation */ | |
167 | if (load_kallsyms()) { | |
168 | fprintf(stderr, "ERROR: loading /proc/kallsyms\n"); | |
169 | return 2; | |
170 | } | |
171 | ||
172 | /* create perf FDs for each CPU */ | |
aa5e2af6 DL |
173 | nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); |
174 | links = calloc(nr_cpus, sizeof(struct bpf_link *)); | |
175 | if (!links) { | |
176 | fprintf(stderr, "ERROR: malloc of links\n"); | |
177 | goto cleanup; | |
72874418 BG |
178 | } |
179 | ||
72874418 | 180 | snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); |
aa5e2af6 | 181 | obj = bpf_object__open_file(filename, NULL); |
0efdcefb | 182 | if (libbpf_get_error(obj)) { |
aa5e2af6 DL |
183 | fprintf(stderr, "ERROR: opening BPF object file failed\n"); |
184 | obj = NULL; | |
185 | goto cleanup; | |
186 | } | |
187 | ||
188 | prog = bpf_object__find_program_by_name(obj, "do_sample"); | |
189 | if (!prog) { | |
190 | fprintf(stderr, "ERROR: finding a prog in obj file failed\n"); | |
191 | goto cleanup; | |
72874418 | 192 | } |
aa5e2af6 DL |
193 | |
194 | /* load BPF program */ | |
195 | if (bpf_object__load(obj)) { | |
196 | fprintf(stderr, "ERROR: loading BPF object file failed\n"); | |
197 | goto cleanup; | |
198 | } | |
199 | ||
200 | map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map"); | |
201 | if (map_fd < 0) { | |
202 | fprintf(stderr, "ERROR: finding a map in obj file failed\n"); | |
203 | goto cleanup; | |
204 | } | |
205 | ||
72874418 | 206 | signal(SIGINT, int_exit); |
ad990dbe | 207 | signal(SIGTERM, int_exit); |
72874418 BG |
208 | |
209 | /* do sampling */ | |
210 | printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n", | |
211 | freq, secs); | |
aa5e2af6 DL |
212 | if (sampling_start(freq, prog, links) != 0) |
213 | goto cleanup; | |
214 | ||
72874418 | 215 | sleep(secs); |
aa5e2af6 | 216 | error = 0; |
72874418 | 217 | |
aa5e2af6 DL |
218 | cleanup: |
219 | sampling_end(links); | |
72874418 | 220 | /* output sample counts */ |
aa5e2af6 DL |
221 | if (!error) |
222 | print_ip_map(map_fd); | |
72874418 | 223 | |
aa5e2af6 DL |
224 | free(links); |
225 | bpf_object__close(obj); | |
226 | return error; | |
72874418 | 227 | } |