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#include <linux/unistd.h>
#include <linux/bpf.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include "libbpf.h"
#include "bpf_util.h"
#define MAX_INDEX 64
#define MAX_STARS 38
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';
}
int main(int argc, char **argv)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
const char *map_filename = "/sys/fs/bpf/tc/globals/lwt_len_hist_map";
uint64_t values[nr_cpus], sum, max_value = 0, data[MAX_INDEX] = {};
uint64_t key = 0, next_key, max_key = 0;
char starstr[MAX_STARS];
int i, map_fd;
map_fd = bpf_obj_get(map_filename);
if (map_fd < 0) {
fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
map_filename, strerror(errno), errno);
return -1;
}
while (bpf_get_next_key(map_fd, &key, &next_key) == 0) {
if (next_key >= MAX_INDEX) {
fprintf(stderr, "Key %lu out of bounds\n", next_key);
continue;
}
bpf_lookup_elem(map_fd, &next_key, values);
sum = 0;
for (i = 0; i < nr_cpus; i++)
sum += values[i];
data[next_key] = sum;
if (sum && next_key > max_key)
max_key = next_key;
if (sum > max_value)
max_value = sum;
key = next_key;
}
for (i = 1; i <= max_key + 1; i++) {
stars(starstr, data[i - 1], max_value, MAX_STARS);
printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
(1l << i) >> 1, (1l << i) - 1, data[i - 1],
MAX_STARS, starstr);
}
close(map_fd);
return 0;
}
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