78 lines · c
1// SPDX-License-Identifier: GPL-2.02#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 6416#define MAX_STARS 3817 18static 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 29int 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