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39111695 AS |
1 | /* This program is free software; you can redistribute it and/or |
2 | * modify it under the terms of version 2 of the GNU General Public | |
3 | * License as published by the Free Software Foundation. | |
4 | */ | |
5 | #include <stdio.h> | |
6 | #include <unistd.h> | |
7 | #include <stdlib.h> | |
8 | #include <stdbool.h> | |
9 | #include <string.h> | |
10 | #include <fcntl.h> | |
11 | #include <poll.h> | |
12 | #include <sys/ioctl.h> | |
13 | #include <linux/perf_event.h> | |
14 | #include <linux/bpf.h> | |
15 | #include <errno.h> | |
16 | #include <assert.h> | |
17 | #include <sys/syscall.h> | |
18 | #include <sys/ioctl.h> | |
19 | #include <sys/mman.h> | |
20 | #include <time.h> | |
21 | #include <signal.h> | |
22 | #include "libbpf.h" | |
23 | #include "bpf_load.h" | |
205c8ada | 24 | #include "perf-sys.h" |
39111695 AS |
25 | |
26 | static int pmu_fd; | |
27 | ||
28 | int page_size; | |
29 | int page_cnt = 8; | |
30 | volatile struct perf_event_mmap_page *header; | |
31 | ||
32 | typedef void (*print_fn)(void *data, int size); | |
33 | ||
34 | static int perf_event_mmap(int fd) | |
35 | { | |
36 | void *base; | |
37 | int mmap_size; | |
38 | ||
39 | page_size = getpagesize(); | |
40 | mmap_size = page_size * (page_cnt + 1); | |
41 | ||
42 | base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); | |
43 | if (base == MAP_FAILED) { | |
44 | printf("mmap err\n"); | |
45 | return -1; | |
46 | } | |
47 | ||
48 | header = base; | |
49 | return 0; | |
50 | } | |
51 | ||
52 | static int perf_event_poll(int fd) | |
53 | { | |
54 | struct pollfd pfd = { .fd = fd, .events = POLLIN }; | |
55 | ||
56 | return poll(&pfd, 1, 1000); | |
57 | } | |
58 | ||
59 | struct perf_event_sample { | |
60 | struct perf_event_header header; | |
61 | __u32 size; | |
62 | char data[]; | |
63 | }; | |
64 | ||
96c2fb69 | 65 | static void perf_event_read(print_fn fn) |
39111695 AS |
66 | { |
67 | __u64 data_tail = header->data_tail; | |
68 | __u64 data_head = header->data_head; | |
69 | __u64 buffer_size = page_cnt * page_size; | |
70 | void *base, *begin, *end; | |
71 | char buf[256]; | |
72 | ||
73 | asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */ | |
74 | if (data_head == data_tail) | |
75 | return; | |
76 | ||
77 | base = ((char *)header) + page_size; | |
78 | ||
79 | begin = base + data_tail % buffer_size; | |
80 | end = base + data_head % buffer_size; | |
81 | ||
82 | while (begin != end) { | |
83 | struct perf_event_sample *e; | |
84 | ||
85 | e = begin; | |
86 | if (begin + e->header.size > base + buffer_size) { | |
87 | long len = base + buffer_size - begin; | |
88 | ||
89 | assert(len < e->header.size); | |
90 | memcpy(buf, begin, len); | |
91 | memcpy(buf + len, base, e->header.size - len); | |
92 | e = (void *) buf; | |
93 | begin = base + e->header.size - len; | |
94 | } else if (begin + e->header.size == base + buffer_size) { | |
95 | begin = base; | |
96 | } else { | |
97 | begin += e->header.size; | |
98 | } | |
99 | ||
100 | if (e->header.type == PERF_RECORD_SAMPLE) { | |
101 | fn(e->data, e->size); | |
102 | } else if (e->header.type == PERF_RECORD_LOST) { | |
103 | struct { | |
104 | struct perf_event_header header; | |
105 | __u64 id; | |
106 | __u64 lost; | |
107 | } *lost = (void *) e; | |
108 | printf("lost %lld events\n", lost->lost); | |
109 | } else { | |
110 | printf("unknown event type=%d size=%d\n", | |
111 | e->header.type, e->header.size); | |
112 | } | |
113 | } | |
114 | ||
115 | __sync_synchronize(); /* smp_mb() */ | |
116 | header->data_tail = data_head; | |
117 | } | |
118 | ||
119 | static __u64 time_get_ns(void) | |
120 | { | |
121 | struct timespec ts; | |
122 | ||
123 | clock_gettime(CLOCK_MONOTONIC, &ts); | |
124 | return ts.tv_sec * 1000000000ull + ts.tv_nsec; | |
125 | } | |
126 | ||
127 | static __u64 start_time; | |
128 | ||
129 | #define MAX_CNT 100000ll | |
130 | ||
131 | static void print_bpf_output(void *data, int size) | |
132 | { | |
133 | static __u64 cnt; | |
134 | struct { | |
135 | __u64 pid; | |
136 | __u64 cookie; | |
137 | } *e = data; | |
138 | ||
139 | if (e->cookie != 0x12345678) { | |
140 | printf("BUG pid %llx cookie %llx sized %d\n", | |
141 | e->pid, e->cookie, size); | |
142 | kill(0, SIGINT); | |
143 | } | |
144 | ||
145 | cnt++; | |
146 | ||
147 | if (cnt == MAX_CNT) { | |
148 | printf("recv %lld events per sec\n", | |
149 | MAX_CNT * 1000000000ll / (time_get_ns() - start_time)); | |
150 | kill(0, SIGINT); | |
151 | } | |
152 | } | |
153 | ||
154 | static void test_bpf_perf_event(void) | |
155 | { | |
156 | struct perf_event_attr attr = { | |
157 | .sample_type = PERF_SAMPLE_RAW, | |
158 | .type = PERF_TYPE_SOFTWARE, | |
159 | .config = PERF_COUNT_SW_BPF_OUTPUT, | |
160 | }; | |
161 | int key = 0; | |
162 | ||
205c8ada | 163 | pmu_fd = sys_perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0); |
39111695 AS |
164 | |
165 | assert(pmu_fd >= 0); | |
d40fc181 | 166 | assert(bpf_map_update_elem(map_fd[0], &key, &pmu_fd, BPF_ANY) == 0); |
39111695 AS |
167 | ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0); |
168 | } | |
169 | ||
170 | int main(int argc, char **argv) | |
171 | { | |
172 | char filename[256]; | |
173 | FILE *f; | |
174 | ||
175 | snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); | |
176 | ||
177 | if (load_bpf_file(filename)) { | |
178 | printf("%s", bpf_log_buf); | |
179 | return 1; | |
180 | } | |
181 | ||
182 | test_bpf_perf_event(); | |
183 | ||
184 | if (perf_event_mmap(pmu_fd) < 0) | |
185 | return 1; | |
186 | ||
187 | f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r"); | |
188 | (void) f; | |
189 | ||
190 | start_time = time_get_ns(); | |
191 | for (;;) { | |
192 | perf_event_poll(pmu_fd); | |
193 | perf_event_read(print_bpf_output); | |
194 | } | |
195 | ||
196 | return 0; | |
197 | } |