1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/unistd.h>
3 #include <linux/bpf.h>
4
5 #include <stdlib.h>
6 #include <stdio.h>
7 #include <unistd.h>
8 #include <string.h>
9 #include <errno.h>
10 #include <arpa/inet.h>
11
12 #include <bpf/bpf.h>
13 #include "bpf_util.h"
14
15 #define MAX_INDEX 64
16 #define MAX_STARS 38
17
18 static void stars(char *str, long val, long max, int width)
19 {
20 int i;
21
22 for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)
23 str[i] = '*';
24 if (val > max)
25 str[i - 1] = '+';
26 str[i] = '\0';
27 }
28
29 int main(int argc, char **argv)
30 {
31 unsigned int nr_cpus = bpf_num_possible_cpus();
32 const char *map_filename = "/sys/fs/bpf/tc/globals/lwt_len_hist_map";
33 uint64_t values[nr_cpus], sum, max_value = 0, data[MAX_INDEX] = {};
34 uint64_t key = 0, next_key, max_key = 0;
35 char starstr[MAX_STARS];
36 int i, map_fd;
37
38 map_fd = bpf_obj_get(map_filename);
39 if (map_fd < 0) {
40 fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
41 map_filename, strerror(errno), errno);
42 return -1;
43 }
44
45 while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0) {
46 if (next_key >= MAX_INDEX) {
47 fprintf(stderr, "Key %lu out of bounds\n", next_key);
48 continue;
49 }
50
51 bpf_map_lookup_elem(map_fd, &next_key, values);
52
53 sum = 0;
54 for (i = 0; i < nr_cpus; i++)
55 sum += values[i];
56
57 data[next_key] = sum;
58 if (sum && next_key > max_key)
59 max_key = next_key;
60
61 if (sum > max_value)
62 max_value = sum;
63
64 key = next_key;
65 }
66
67 for (i = 1; i <= max_key + 1; i++) {
68 stars(starstr, data[i - 1], max_value, MAX_STARS);
69 printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
70 (1l << i) >> 1, (1l << i) - 1, data[i - 1],
71 MAX_STARS, starstr);
72 }
73
74 close(map_fd);
75
76 return 0;
77 }
78
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