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