1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com |
3 | * Copyright (c) 2015 BMW Car IT GmbH |
4 | */ |
5 | #include <stdio.h> |
6 | #include <unistd.h> |
7 | #include <stdlib.h> |
8 | #include <signal.h> |
9 | #include <bpf/libbpf.h> |
10 | #include <bpf/bpf.h> |
11 | |
12 | #define MAX_ENTRIES 20 |
13 | #define MAX_CPU 4 |
14 | #define MAX_STARS 40 |
15 | |
16 | struct cpu_hist { |
17 | long data[MAX_ENTRIES]; |
18 | long max; |
19 | }; |
20 | |
21 | static struct cpu_hist cpu_hist[MAX_CPU]; |
22 | |
23 | static void stars(char *str, long val, long max, int width) |
24 | { |
25 | int i; |
26 | |
27 | for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++) |
28 | str[i] = '*'; |
29 | if (val > max) |
30 | str[i - 1] = '+'; |
31 | str[i] = '\0'; |
32 | } |
33 | |
34 | static void print_hist(void) |
35 | { |
36 | char starstr[MAX_STARS]; |
37 | struct cpu_hist *hist; |
38 | int i, j; |
39 | |
40 | /* clear screen */ |
41 | printf(format: "\033[2J" ); |
42 | |
43 | for (j = 0; j < MAX_CPU; j++) { |
44 | hist = &cpu_hist[j]; |
45 | |
46 | /* ignore CPUs without data (maybe offline?) */ |
47 | if (hist->max == 0) |
48 | continue; |
49 | |
50 | printf(format: "CPU %d\n" , j); |
51 | printf(format: " latency : count distribution\n" ); |
52 | for (i = 1; i <= MAX_ENTRIES; i++) { |
53 | stars(str: starstr, val: hist->data[i - 1], max: hist->max, MAX_STARS); |
54 | printf(format: "%8ld -> %-8ld : %-8ld |%-*s|\n" , |
55 | (1l << i) >> 1, (1l << i) - 1, |
56 | hist->data[i - 1], MAX_STARS, starstr); |
57 | } |
58 | } |
59 | } |
60 | |
61 | static void get_data(int fd) |
62 | { |
63 | long key, value; |
64 | int c, i; |
65 | |
66 | for (i = 0; i < MAX_CPU; i++) |
67 | cpu_hist[i].max = 0; |
68 | |
69 | for (c = 0; c < MAX_CPU; c++) { |
70 | for (i = 0; i < MAX_ENTRIES; i++) { |
71 | key = c * MAX_ENTRIES + i; |
72 | bpf_map_lookup_elem(fd, &key, &value); |
73 | |
74 | cpu_hist[c].data[i] = value; |
75 | if (value > cpu_hist[c].max) |
76 | cpu_hist[c].max = value; |
77 | } |
78 | } |
79 | } |
80 | |
81 | int main(int argc, char **argv) |
82 | { |
83 | struct bpf_link *links[2]; |
84 | struct bpf_program *prog; |
85 | struct bpf_object *obj; |
86 | char filename[256]; |
87 | int map_fd, i = 0; |
88 | |
89 | snprintf(s: filename, maxlen: sizeof(filename), format: "%s_kern.o" , argv[0]); |
90 | obj = bpf_object__open_file(filename, NULL); |
91 | if (libbpf_get_error(obj)) { |
92 | fprintf(stderr, format: "ERROR: opening BPF object file failed\n" ); |
93 | return 0; |
94 | } |
95 | |
96 | /* load BPF program */ |
97 | if (bpf_object__load(obj)) { |
98 | fprintf(stderr, format: "ERROR: loading BPF object file failed\n" ); |
99 | goto cleanup; |
100 | } |
101 | |
102 | map_fd = bpf_object__find_map_fd_by_name(obj, "my_lat" ); |
103 | if (map_fd < 0) { |
104 | fprintf(stderr, format: "ERROR: finding a map in obj file failed\n" ); |
105 | goto cleanup; |
106 | } |
107 | |
108 | bpf_object__for_each_program(prog, obj) { |
109 | links[i] = bpf_program__attach(prog); |
110 | if (libbpf_get_error(links[i])) { |
111 | fprintf(stderr, format: "ERROR: bpf_program__attach failed\n" ); |
112 | links[i] = NULL; |
113 | goto cleanup; |
114 | } |
115 | i++; |
116 | } |
117 | |
118 | while (1) { |
119 | get_data(fd: map_fd); |
120 | print_hist(); |
121 | sleep(seconds: 5); |
122 | } |
123 | |
124 | cleanup: |
125 | for (i--; i >= 0; i--) |
126 | bpf_link__destroy(links[i]); |
127 | |
128 | bpf_object__close(obj); |
129 | return 0; |
130 | } |
131 | |