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