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
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
* Copyright (c) 2015 BMW Car IT GmbH
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <bpf/libbpf.h>
#include <bpf/bpf.h>
#define MAX_ENTRIES 20
#define MAX_CPU 4
#define MAX_STARS 40
struct cpu_hist {
long data[MAX_ENTRIES];
long max;
};
static struct cpu_hist cpu_hist[MAX_CPU];
static void stars(char *str, long val, long max, int width)
{
int i;
for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)
str[i] = '*';
if (val > max)
str[i - 1] = '+';
str[i] = '\0';
}
static void print_hist(void)
{
char starstr[MAX_STARS];
struct cpu_hist *hist;
int i, j;
/* clear screen */
printf("\033[2J");
for (j = 0; j < MAX_CPU; j++) {
hist = &cpu_hist[j];
/* ignore CPUs without data (maybe offline?) */
if (hist->max == 0)
continue;
printf("CPU %d\n", j);
printf(" latency : count distribution\n");
for (i = 1; i <= MAX_ENTRIES; i++) {
stars(starstr, hist->data[i - 1], hist->max, MAX_STARS);
printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
(1l << i) >> 1, (1l << i) - 1,
hist->data[i - 1], MAX_STARS, starstr);
}
}
}
static void get_data(int fd)
{
long key, value;
int c, i;
for (i = 0; i < MAX_CPU; i++)
cpu_hist[i].max = 0;
for (c = 0; c < MAX_CPU; c++) {
for (i = 0; i < MAX_ENTRIES; i++) {
key = c * MAX_ENTRIES + i;
bpf_map_lookup_elem(fd, &key, &value);
cpu_hist[c].data[i] = value;
if (value > cpu_hist[c].max)
cpu_hist[c].max = value;
}
}
}
int main(int argc, char **argv)
{
struct bpf_link *links[2];
struct bpf_program *prog;
struct bpf_object *obj;
char filename[256];
int map_fd, i = 0;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
obj = bpf_object__open_file(filename, NULL);
if (libbpf_get_error(obj)) {
fprintf(stderr, "ERROR: opening BPF object file failed\n");
return 0;
}
/* load BPF program */
if (bpf_object__load(obj)) {
fprintf(stderr, "ERROR: loading BPF object file failed\n");
goto cleanup;
}
map_fd = bpf_object__find_map_fd_by_name(obj, "my_lat");
if (map_fd < 0) {
fprintf(stderr, "ERROR: finding a map in obj file failed\n");
goto cleanup;
}
bpf_object__for_each_program(prog, obj) {
links[i] = bpf_program__attach(prog);
if (libbpf_get_error(links[i])) {
fprintf(stderr, "ERROR: bpf_program__attach failed\n");
links[i] = NULL;
goto cleanup;
}
i++;
}
while (1) {
get_data(map_fd);
print_hist();
sleep(5);
}
cleanup:
for (i--; i >= 0; i--)
bpf_link__destroy(links[i]);
bpf_object__close(obj);
return 0;
}
|
