samples/bpf/tracex2_user.c

   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 }