1 #include <stdio.h> 2 #include <unistd.h> 3 #include <stdlib.h> 4 #include <signal.h> 5 #include <linux/bpf.h> 6 #include "libbpf.h" 7 #include "bpf_load.h" 8 9 #define MAX_INDEX 64 10 #define MAX_STARS 38 11 12 static void stars(char *str, long val, long max, int width) 13 { 14 int i; 15 16 for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++) 17 str[i] = '*'; 18 if (val > max) 19 str[i - 1] = '+'; 20 str[i] = '\0'; 21 } 22 23 static void print_hist(int fd) 24 { 25 int key; 26 long value; 27 long data[MAX_INDEX] = {}; 28 char starstr[MAX_STARS]; 29 int i; 30 int max_ind = -1; 31 long max_value = 0; 32 33 for (key = 0; key < MAX_INDEX; key++) { 34 bpf_lookup_elem(fd, &key, &value); 35 data[key] = value; 36 if (value && key > max_ind) 37 max_ind = key; 38 if (value > max_value) 39 max_value = value; 40 } 41 42 printf(" syscall write() stats\n"); 43 printf(" byte_size : count distribution\n"); 44 for (i = 1; i <= max_ind + 1; i++) { 45 stars(starstr, data[i - 1], max_value, MAX_STARS); 46 printf("%8ld -> %-8ld : %-8ld |%-*s|\n", 47 (1l << i) >> 1, (1l << i) - 1, data[i - 1], 48 MAX_STARS, starstr); 49 } 50 } 51 static void int_exit(int sig) 52 { 53 print_hist(map_fd[1]); 54 exit(0); 55 } 56 57 int main(int ac, char **argv) 58 { 59 char filename[256]; 60 long key, next_key, value; 61 FILE *f; 62 int i; 63 64 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); 65 66 signal(SIGINT, int_exit); 67 68 /* start 'ping' in the background to have some kfree_skb events */ 69 f = popen("ping -c5 localhost", "r"); 70 (void) f; 71 72 /* start 'dd' in the background to have plenty of 'write' syscalls */ 73 f = popen("dd if=/dev/zero of=/dev/null count=5000000", "r"); 74 (void) f; 75 76 if (load_bpf_file(filename)) { 77 printf("%s", bpf_log_buf); 78 return 1; 79 } 80 81 for (i = 0; i < 5; i++) { 82 key = 0; 83 while (bpf_get_next_key(map_fd[0], &key, &next_key) == 0) { 84 bpf_lookup_elem(map_fd[0], &next_key, &value); 85 printf("location 0x%lx count %ld\n", next_key, value); 86 key = next_key; 87 } 88 if (key) 89 printf("\n"); 90 sleep(1); 91 } 92 print_hist(map_fd[1]); 93 94 return 0; 95 } 96