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