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1c47910e AS |
1 | /* Copyright (c) 2016 Facebook |
2 | * | |
3 | * This program is free software; you can redistribute it and/or | |
4 | * modify it under the terms of version 2 of the GNU General Public | |
5 | * License as published by the Free Software Foundation. | |
6 | */ | |
7 | #include <stdio.h> | |
8 | #include <unistd.h> | |
9 | #include <stdlib.h> | |
10 | #include <stdbool.h> | |
11 | #include <string.h> | |
12 | #include <fcntl.h> | |
13 | #include <poll.h> | |
14 | #include <sys/ioctl.h> | |
15 | #include <linux/perf_event.h> | |
16 | #include <linux/bpf.h> | |
17 | #include <signal.h> | |
18 | #include <assert.h> | |
19 | #include <errno.h> | |
20 | #include <sys/resource.h> | |
21 | #include "libbpf.h" | |
22 | #include "bpf_load.h" | |
23 | ||
24 | #define SAMPLE_FREQ 50 | |
25 | ||
26 | static bool sys_read_seen, sys_write_seen; | |
27 | ||
28 | static void print_ksym(__u64 addr) | |
29 | { | |
30 | struct ksym *sym; | |
31 | ||
32 | if (!addr) | |
33 | return; | |
34 | sym = ksym_search(addr); | |
35 | printf("%s;", sym->name); | |
36 | if (!strcmp(sym->name, "sys_read")) | |
37 | sys_read_seen = true; | |
38 | else if (!strcmp(sym->name, "sys_write")) | |
39 | sys_write_seen = true; | |
40 | } | |
41 | ||
42 | static void print_addr(__u64 addr) | |
43 | { | |
44 | if (!addr) | |
45 | return; | |
46 | printf("%llx;", addr); | |
47 | } | |
48 | ||
49 | #define TASK_COMM_LEN 16 | |
50 | ||
51 | struct key_t { | |
52 | char comm[TASK_COMM_LEN]; | |
53 | __u32 kernstack; | |
54 | __u32 userstack; | |
55 | }; | |
56 | ||
57 | static void print_stack(struct key_t *key, __u64 count) | |
58 | { | |
59 | __u64 ip[PERF_MAX_STACK_DEPTH] = {}; | |
60 | static bool warned; | |
61 | int i; | |
62 | ||
63 | printf("%3lld %s;", count, key->comm); | |
64 | if (bpf_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) { | |
65 | printf("---;"); | |
66 | } else { | |
67 | for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--) | |
68 | print_ksym(ip[i]); | |
69 | } | |
70 | printf("-;"); | |
71 | if (bpf_lookup_elem(map_fd[1], &key->userstack, ip) != 0) { | |
72 | printf("---;"); | |
73 | } else { | |
74 | for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--) | |
75 | print_addr(ip[i]); | |
76 | } | |
77 | printf("\n"); | |
78 | ||
79 | if (key->kernstack == -EEXIST && !warned) { | |
80 | printf("stackmap collisions seen. Consider increasing size\n"); | |
81 | warned = true; | |
82 | } else if ((int)key->kernstack < 0 && (int)key->userstack < 0) { | |
83 | printf("err stackid %d %d\n", key->kernstack, key->userstack); | |
84 | } | |
85 | } | |
86 | ||
87 | static void int_exit(int sig) | |
88 | { | |
89 | kill(0, SIGKILL); | |
90 | exit(0); | |
91 | } | |
92 | ||
93 | static void print_stacks(void) | |
94 | { | |
95 | struct key_t key = {}, next_key; | |
96 | __u64 value; | |
97 | __u32 stackid = 0, next_id; | |
98 | int fd = map_fd[0], stack_map = map_fd[1]; | |
99 | ||
100 | sys_read_seen = sys_write_seen = false; | |
101 | while (bpf_get_next_key(fd, &key, &next_key) == 0) { | |
102 | bpf_lookup_elem(fd, &next_key, &value); | |
103 | print_stack(&next_key, value); | |
104 | bpf_delete_elem(fd, &next_key); | |
105 | key = next_key; | |
106 | } | |
107 | ||
108 | if (!sys_read_seen || !sys_write_seen) { | |
109 | printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n"); | |
110 | int_exit(0); | |
111 | } | |
112 | ||
113 | /* clear stack map */ | |
114 | while (bpf_get_next_key(stack_map, &stackid, &next_id) == 0) { | |
115 | bpf_delete_elem(stack_map, &next_id); | |
116 | stackid = next_id; | |
117 | } | |
118 | } | |
119 | ||
120 | static void test_perf_event_all_cpu(struct perf_event_attr *attr) | |
121 | { | |
122 | int nr_cpus = sysconf(_SC_NPROCESSORS_CONF); | |
123 | int *pmu_fd = malloc(nr_cpus * sizeof(int)); | |
124 | int i; | |
125 | ||
126 | /* open perf_event on all cpus */ | |
127 | for (i = 0; i < nr_cpus; i++) { | |
128 | pmu_fd[i] = perf_event_open(attr, -1, i, -1, 0); | |
129 | if (pmu_fd[i] < 0) { | |
130 | printf("perf_event_open failed\n"); | |
131 | goto all_cpu_err; | |
132 | } | |
133 | assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0); | |
134 | assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0); | |
135 | } | |
136 | system("dd if=/dev/zero of=/dev/null count=5000k"); | |
137 | print_stacks(); | |
138 | all_cpu_err: | |
139 | for (i--; i >= 0; i--) | |
140 | close(pmu_fd[i]); | |
141 | free(pmu_fd); | |
142 | } | |
143 | ||
144 | static void test_perf_event_task(struct perf_event_attr *attr) | |
145 | { | |
146 | int pmu_fd; | |
147 | ||
148 | /* open task bound event */ | |
149 | pmu_fd = perf_event_open(attr, 0, -1, -1, 0); | |
150 | if (pmu_fd < 0) { | |
151 | printf("perf_event_open failed\n"); | |
152 | return; | |
153 | } | |
154 | assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0); | |
155 | assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0) == 0); | |
156 | system("dd if=/dev/zero of=/dev/null count=5000k"); | |
157 | print_stacks(); | |
158 | close(pmu_fd); | |
159 | } | |
160 | ||
161 | static void test_bpf_perf_event(void) | |
162 | { | |
163 | struct perf_event_attr attr_type_hw = { | |
164 | .sample_freq = SAMPLE_FREQ, | |
165 | .freq = 1, | |
166 | .type = PERF_TYPE_HARDWARE, | |
167 | .config = PERF_COUNT_HW_CPU_CYCLES, | |
168 | .inherit = 1, | |
169 | }; | |
170 | struct perf_event_attr attr_type_sw = { | |
171 | .sample_freq = SAMPLE_FREQ, | |
172 | .freq = 1, | |
173 | .type = PERF_TYPE_SOFTWARE, | |
174 | .config = PERF_COUNT_SW_CPU_CLOCK, | |
175 | .inherit = 1, | |
176 | }; | |
177 | ||
178 | test_perf_event_all_cpu(&attr_type_hw); | |
179 | test_perf_event_task(&attr_type_hw); | |
180 | test_perf_event_all_cpu(&attr_type_sw); | |
181 | test_perf_event_task(&attr_type_sw); | |
182 | } | |
183 | ||
184 | ||
185 | int main(int argc, char **argv) | |
186 | { | |
187 | struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; | |
188 | char filename[256]; | |
189 | ||
190 | snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); | |
191 | setrlimit(RLIMIT_MEMLOCK, &r); | |
192 | ||
193 | signal(SIGINT, int_exit); | |
194 | ||
195 | if (load_kallsyms()) { | |
196 | printf("failed to process /proc/kallsyms\n"); | |
197 | return 1; | |
198 | } | |
199 | ||
200 | if (load_bpf_file(filename)) { | |
201 | printf("%s", bpf_log_buf); | |
202 | return 2; | |
203 | } | |
204 | ||
205 | if (fork() == 0) { | |
206 | read_trace_pipe(); | |
207 | return 0; | |
208 | } | |
209 | test_bpf_perf_event(); | |
210 | ||
211 | int_exit(0); | |
212 | return 0; | |
213 | } |