1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <pthread.h>
#include <sched.h>
#include <sys/socket.h>
#include <test_progs.h>
static void on_sample(void *ctx, int cpu, void *data, __u32 size)
{
int cpu_data = *(int *)data, duration = 0;
cpu_set_t *cpu_seen = ctx;
if (cpu_data != cpu)
CHECK(cpu_data != cpu, "check_cpu_data",
"cpu_data %d != cpu %d\n", cpu_data, cpu);
CPU_SET(cpu, cpu_seen);
}
void test_perf_buffer(void)
{
int err, prog_fd, nr_cpus, i, duration = 0;
const char *prog_name = "kprobe/sys_nanosleep";
const char *file = "./test_perf_buffer.o";
struct perf_buffer_opts pb_opts = {};
struct bpf_map *perf_buf_map;
cpu_set_t cpu_set, cpu_seen;
struct bpf_program *prog;
struct bpf_object *obj;
struct perf_buffer *pb;
struct bpf_link *link;
nr_cpus = libbpf_num_possible_cpus();
if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
return;
/* load program */
err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))
return;
prog = bpf_object__find_program_by_title(obj, prog_name);
if (CHECK(!prog, "find_probe", "prog '%s' not found\n", prog_name))
goto out_close;
/* load map */
perf_buf_map = bpf_object__find_map_by_name(obj, "perf_buf_map");
if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n"))
goto out_close;
/* attach kprobe */
link = bpf_program__attach_kprobe(prog, false /* retprobe */,
SYS_NANOSLEEP_KPROBE_NAME);
if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link)))
goto out_close;
/* set up perf buffer */
pb_opts.sample_cb = on_sample;
pb_opts.ctx = &cpu_seen;
pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts);
if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
goto out_detach;
/* trigger kprobe on every CPU */
CPU_ZERO(&cpu_seen);
for (i = 0; i < nr_cpus; i++) {
CPU_ZERO(&cpu_set);
CPU_SET(i, &cpu_set);
err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set),
&cpu_set);
if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n",
i, err))
goto out_detach;
usleep(1);
}
/* read perf buffer */
err = perf_buffer__poll(pb, 100);
if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
goto out_free_pb;
if (CHECK(CPU_COUNT(&cpu_seen) != nr_cpus, "seen_cpu_cnt",
"expect %d, seen %d\n", nr_cpus, CPU_COUNT(&cpu_seen)))
goto out_free_pb;
out_free_pb:
perf_buffer__free(pb);
out_detach:
bpf_link__destroy(link);
out_close:
bpf_object__close(obj);
}
|
