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72874418 BG |
1 | /* |
2 | * sampleip: sample instruction pointer and frequency count in a BPF map. | |
3 | * | |
4 | * Copyright 2016 Netflix, Inc. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of version 2 of the GNU General Public | |
8 | * License as published by the Free Software Foundation. | |
9 | */ | |
10 | #include <stdio.h> | |
11 | #include <stdlib.h> | |
12 | #include <stdio.h> | |
13 | #include <unistd.h> | |
14 | #include <errno.h> | |
15 | #include <signal.h> | |
16 | #include <string.h> | |
17 | #include <assert.h> | |
18 | #include <linux/perf_event.h> | |
19 | #include <linux/ptrace.h> | |
20 | #include <linux/bpf.h> | |
21 | #include <sys/ioctl.h> | |
22 | #include "libbpf.h" | |
23 | #include "bpf_load.h" | |
205c8ada | 24 | #include "perf-sys.h" |
72874418 BG |
25 | |
26 | #define DEFAULT_FREQ 99 | |
27 | #define DEFAULT_SECS 5 | |
28 | #define MAX_IPS 8192 | |
29 | #define PAGE_OFFSET 0xffff880000000000 | |
30 | ||
31 | static int nr_cpus; | |
32 | ||
33 | static void usage(void) | |
34 | { | |
35 | printf("USAGE: sampleip [-F freq] [duration]\n"); | |
36 | printf(" -F freq # sample frequency (Hertz), default 99\n"); | |
37 | printf(" duration # sampling duration (seconds), default 5\n"); | |
38 | } | |
39 | ||
40 | static int sampling_start(int *pmu_fd, int freq) | |
41 | { | |
42 | int i; | |
43 | ||
44 | struct perf_event_attr pe_sample_attr = { | |
45 | .type = PERF_TYPE_SOFTWARE, | |
46 | .freq = 1, | |
47 | .sample_period = freq, | |
48 | .config = PERF_COUNT_SW_CPU_CLOCK, | |
49 | .inherit = 1, | |
50 | }; | |
51 | ||
52 | for (i = 0; i < nr_cpus; i++) { | |
205c8ada | 53 | pmu_fd[i] = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i, |
72874418 BG |
54 | -1 /* group_fd */, 0 /* flags */); |
55 | if (pmu_fd[i] < 0) { | |
56 | fprintf(stderr, "ERROR: Initializing perf sampling\n"); | |
57 | return 1; | |
58 | } | |
59 | assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, | |
60 | prog_fd[0]) == 0); | |
61 | assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0); | |
62 | } | |
63 | ||
64 | return 0; | |
65 | } | |
66 | ||
67 | static void sampling_end(int *pmu_fd) | |
68 | { | |
69 | int i; | |
70 | ||
71 | for (i = 0; i < nr_cpus; i++) | |
72 | close(pmu_fd[i]); | |
73 | } | |
74 | ||
75 | struct ipcount { | |
76 | __u64 ip; | |
77 | __u32 count; | |
78 | }; | |
79 | ||
80 | /* used for sorting */ | |
81 | struct ipcount counts[MAX_IPS]; | |
82 | ||
83 | static int count_cmp(const void *p1, const void *p2) | |
84 | { | |
85 | return ((struct ipcount *)p1)->count - ((struct ipcount *)p2)->count; | |
86 | } | |
87 | ||
88 | static void print_ip_map(int fd) | |
89 | { | |
90 | struct ksym *sym; | |
91 | __u64 key, next_key; | |
92 | __u32 value; | |
93 | int i, max; | |
94 | ||
95 | printf("%-19s %-32s %s\n", "ADDR", "KSYM", "COUNT"); | |
96 | ||
97 | /* fetch IPs and counts */ | |
98 | key = 0, i = 0; | |
d40fc181 JS |
99 | while (bpf_map_get_next_key(fd, &key, &next_key) == 0) { |
100 | bpf_map_lookup_elem(fd, &next_key, &value); | |
72874418 BG |
101 | counts[i].ip = next_key; |
102 | counts[i++].count = value; | |
103 | key = next_key; | |
104 | } | |
105 | max = i; | |
106 | ||
107 | /* sort and print */ | |
108 | qsort(counts, max, sizeof(struct ipcount), count_cmp); | |
109 | for (i = 0; i < max; i++) { | |
110 | if (counts[i].ip > PAGE_OFFSET) { | |
111 | sym = ksym_search(counts[i].ip); | |
112 | printf("0x%-17llx %-32s %u\n", counts[i].ip, sym->name, | |
113 | counts[i].count); | |
114 | } else { | |
115 | printf("0x%-17llx %-32s %u\n", counts[i].ip, "(user)", | |
116 | counts[i].count); | |
117 | } | |
118 | } | |
119 | ||
120 | if (max == MAX_IPS) { | |
121 | printf("WARNING: IP hash was full (max %d entries); ", max); | |
122 | printf("may have dropped samples\n"); | |
123 | } | |
124 | } | |
125 | ||
126 | static void int_exit(int sig) | |
127 | { | |
128 | printf("\n"); | |
129 | print_ip_map(map_fd[0]); | |
130 | exit(0); | |
131 | } | |
132 | ||
133 | int main(int argc, char **argv) | |
134 | { | |
135 | char filename[256]; | |
136 | int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS; | |
137 | ||
138 | /* process arguments */ | |
139 | while ((opt = getopt(argc, argv, "F:h")) != -1) { | |
140 | switch (opt) { | |
141 | case 'F': | |
142 | freq = atoi(optarg); | |
143 | break; | |
144 | case 'h': | |
145 | default: | |
146 | usage(); | |
147 | return 0; | |
148 | } | |
149 | } | |
150 | if (argc - optind == 1) | |
151 | secs = atoi(argv[optind]); | |
152 | if (freq == 0 || secs == 0) { | |
153 | usage(); | |
154 | return 1; | |
155 | } | |
156 | ||
157 | /* initialize kernel symbol translation */ | |
158 | if (load_kallsyms()) { | |
159 | fprintf(stderr, "ERROR: loading /proc/kallsyms\n"); | |
160 | return 2; | |
161 | } | |
162 | ||
163 | /* create perf FDs for each CPU */ | |
164 | nr_cpus = sysconf(_SC_NPROCESSORS_CONF); | |
165 | pmu_fd = malloc(nr_cpus * sizeof(int)); | |
166 | if (pmu_fd == NULL) { | |
167 | fprintf(stderr, "ERROR: malloc of pmu_fd\n"); | |
168 | return 1; | |
169 | } | |
170 | ||
171 | /* load BPF program */ | |
172 | snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); | |
173 | if (load_bpf_file(filename)) { | |
174 | fprintf(stderr, "ERROR: loading BPF program (errno %d):\n", | |
175 | errno); | |
176 | if (strcmp(bpf_log_buf, "") == 0) | |
177 | fprintf(stderr, "Try: ulimit -l unlimited\n"); | |
178 | else | |
179 | fprintf(stderr, "%s", bpf_log_buf); | |
180 | return 1; | |
181 | } | |
182 | signal(SIGINT, int_exit); | |
ad990dbe | 183 | signal(SIGTERM, int_exit); |
72874418 BG |
184 | |
185 | /* do sampling */ | |
186 | printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n", | |
187 | freq, secs); | |
188 | if (sampling_start(pmu_fd, freq) != 0) | |
189 | return 1; | |
190 | sleep(secs); | |
191 | sampling_end(pmu_fd); | |
192 | free(pmu_fd); | |
193 | ||
194 | /* output sample counts */ | |
195 | print_ip_map(map_fd[0]); | |
196 | ||
197 | return 0; | |
198 | } |