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