1#include <linux/perf_event.h>
2#include <perf/evlist.h>
3#include <perf/evsel.h>
4#include <perf/cpumap.h>
5#include <perf/threadmap.h>
6#include <perf/mmap.h>
7#include <perf/core.h>
8#include <perf/event.h>
9#include <stdio.h>
10#include <unistd.h>
11
12static int libperf_print(enum libperf_print_level level,
13 const char *fmt, va_list ap)
14{
15 return vfprintf(stderr, format: fmt, arg: ap);
16}
17
18union u64_swap {
19 __u64 val64;
20 __u32 val32[2];
21};
22
23int main(int argc, char **argv)
24{
25 struct perf_evlist *evlist;
26 struct perf_evsel *evsel;
27 struct perf_mmap *map;
28 struct perf_cpu_map *cpus;
29 struct perf_event_attr attr = {
30 .type = PERF_TYPE_HARDWARE,
31 .config = PERF_COUNT_HW_CPU_CYCLES,
32 .disabled = 1,
33 .freq = 1,
34 .sample_freq = 10,
35 .sample_type = PERF_SAMPLE_IP|PERF_SAMPLE_TID|PERF_SAMPLE_CPU|PERF_SAMPLE_PERIOD,
36 };
37 int err = -1;
38 union perf_event *event;
39
40 libperf_init(libperf_print);
41
42 cpus = perf_cpu_map__new_online_cpus();
43 if (!cpus) {
44 fprintf(stderr, format: "failed to create cpus\n");
45 return -1;
46 }
47
48 evlist = perf_evlist__new();
49 if (!evlist) {
50 fprintf(stderr, format: "failed to create evlist\n");
51 goto out_cpus;
52 }
53
54 evsel = perf_evsel__new(&attr);
55 if (!evsel) {
56 fprintf(stderr, format: "failed to create cycles\n");
57 goto out_cpus;
58 }
59
60 perf_evlist__add(evlist, evsel);
61
62 perf_evlist__set_maps(evlist, cpus, NULL);
63
64 err = perf_evlist__open(evlist);
65 if (err) {
66 fprintf(stderr, format: "failed to open evlist\n");
67 goto out_evlist;
68 }
69
70 err = perf_evlist__mmap(evlist, 4);
71 if (err) {
72 fprintf(stderr, format: "failed to mmap evlist\n");
73 goto out_evlist;
74 }
75
76 perf_evlist__enable(evlist);
77 sleep(seconds: 3);
78 perf_evlist__disable(evlist);
79
80 perf_evlist__for_each_mmap(evlist, map, false) {
81 if (perf_mmap__read_init(map) < 0)
82 continue;
83
84 while ((event = perf_mmap__read_event(map)) != NULL) {
85 int cpu, pid, tid;
86 __u64 ip, period, *array;
87 union u64_swap u;
88
89 array = event->sample.array;
90
91 ip = *array;
92 array++;
93
94 u.val64 = *array;
95 pid = u.val32[0];
96 tid = u.val32[1];
97 array++;
98
99 u.val64 = *array;
100 cpu = u.val32[0];
101 array++;
102
103 period = *array;
104
105 fprintf(stdout, format: "cpu %3d, pid %6d, tid %6d, ip %20llx, period %20llu\n",
106 cpu, pid, tid, ip, period);
107
108 perf_mmap__consume(map);
109 }
110
111 perf_mmap__read_done(map);
112 }
113
114out_evlist:
115 perf_evlist__delete(evlist);
116out_cpus:
117 perf_cpu_map__put(cpus);
118 return err;
119}
120

source code of linux/tools/lib/perf/Documentation/examples/sampling.c