samples/bpf/tracex3_user.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
   3  */
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <signal.h>
   7 #include <unistd.h>
   8 #include <stdbool.h>
   9 #include <string.h>
  10
  11 #include <bpf/bpf.h>
  12 #include <bpf/libbpf.h>
  13 #include "bpf_util.h"
  14
  15 #define SLOTS 100
  16
  17 static void clear_stats(int fd)
  18 {
  19         unsigned int nr_cpus = bpf_num_possible_cpus();
  20         __u64 values[nr_cpus];
  21         __u32 key;
  22
  23         memset(values, 0, sizeof(values));
  24         for (key = 0; key < SLOTS; key++)
  25                 bpf_map_update_elem(fd, &key, values, BPF_ANY);
  26 }
  27
  28 const char *color[] = {
  29         "\033[48;5;255m",
  30         "\033[48;5;252m",
  31         "\033[48;5;250m",
  32         "\033[48;5;248m",
  33         "\033[48;5;246m",
  34         "\033[48;5;244m",
  35         "\033[48;5;242m",
  36         "\033[48;5;240m",
  37         "\033[48;5;238m",
  38         "\033[48;5;236m",
  39         "\033[48;5;234m",
  40         "\033[48;5;232m",
  41 };
  42 const int num_colors = ARRAY_SIZE(color);
  43
  44 const char nocolor[] = "\033[00m";
  45
  46 const char *sym[] = {
  47         " ",
  48         " ",
  49         ".",
  50         ".",
  51         "*",
  52         "*",
  53         "o",
  54         "o",
  55         "O",
  56         "O",
  57         "#",
  58         "#",
  59 };
  60
  61 bool full_range = false;
  62 bool text_only = false;
  63
  64 static void print_banner(void)
  65 {
  66         if (full_range)
  67                 printf("|1ns     |10ns     |100ns    |1us      |10us     |100us"
  68                        "    |1ms      |10ms     |100ms    |1s       |10s\n");
  69         else
  70                 printf("|1us      |10us     |100us    |1ms      |10ms     "
  71                        "|100ms    |1s       |10s\n");
  72 }
  73
  74 static void print_hist(int fd)
  75 {
  76         unsigned int nr_cpus = bpf_num_possible_cpus();
  77         __u64 total_events = 0;
  78         long values[nr_cpus];
  79         __u64 max_cnt = 0;
  80         __u64 cnt[SLOTS];
  81         __u64 value;
  82         __u32 key;
  83         int i;
  84
  85         for (key = 0; key < SLOTS; key++) {
  86                 bpf_map_lookup_elem(fd, &key, values);
  87                 value = 0;
  88                 for (i = 0; i < nr_cpus; i++)
  89                         value += values[i];
  90                 cnt[key] = value;
  91                 total_events += value;
  92                 if (value > max_cnt)
  93                         max_cnt = value;
  94         }
  95         clear_stats(fd);
  96         for (key = full_range ? 0 : 29; key < SLOTS; key++) {
  97                 int c = num_colors * cnt[key] / (max_cnt + 1);
  98
  99                 if (text_only)
 100                         printf("%s", sym[c]);
 101                 else
 102                         printf("%s %s", color[c], nocolor);
 103         }
 104         printf(" # %lld\n", total_events);
 105 }
 106
 107 int main(int ac, char **argv)
 108 {
 109         struct bpf_link *links[2];
 110         struct bpf_program *prog;
 111         struct bpf_object *obj;
 112         char filename[256];
 113         int map_fd, i, j = 0;
 114
 115         for (i = 1; i < ac; i++) {
 116                 if (strcmp(argv[i], "-a") == 0) {
 117                         full_range = true;
 118                 } else if (strcmp(argv[i], "-t") == 0) {
 119                         text_only = true;
 120                 } else if (strcmp(argv[i], "-h") == 0) {
 121                         printf("Usage:\n"
 122                                "  -a display wider latency range\n"
 123                                "  -t text only\n");
 124                         return 1;
 125                 }
 126         }
 127
 128         snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]);
 129         obj = bpf_object__open_file(filename, NULL);
 130         if (libbpf_get_error(obj)) {
 131                 fprintf(stderr, "ERROR: opening BPF object file failed\n");
 132                 return 0;
 133         }
 134
 135         /* load BPF program */
 136         if (bpf_object__load(obj)) {
 137                 fprintf(stderr, "ERROR: loading BPF object file failed\n");
 138                 goto cleanup;
 139         }
 140
 141         map_fd = bpf_object__find_map_fd_by_name(obj, "lat_map");
 142         if (map_fd < 0) {
 143                 fprintf(stderr, "ERROR: finding a map in obj file failed\n");
 144                 goto cleanup;
 145         }
 146
 147         bpf_object__for_each_program(prog, obj) {
 148                 links[j] = bpf_program__attach(prog);
 149                 if (libbpf_get_error(links[j])) {
 150                         fprintf(stderr, "ERROR: bpf_program__attach failed\n");
 151                         links[j] = NULL;
 152                         goto cleanup;
 153                 }
 154                 j++;
 155         }
 156
 157         printf("  heatmap of IO latency\n");
 158         if (text_only)
 159                 printf("  %s", sym[num_colors - 1]);
 160         else
 161                 printf("  %s %s", color[num_colors - 1], nocolor);
 162         printf(" - many events with this latency\n");
 163
 164         if (text_only)
 165                 printf("  %s", sym[0]);
 166         else
 167                 printf("  %s %s", color[0], nocolor);
 168         printf(" - few events\n");
 169
 170         for (i = 0; ; i++) {
 171                 if (i % 20 == 0)
 172                         print_banner();
 173                 print_hist(map_fd);
 174                 sleep(2);
 175         }
 176
 177 cleanup:
 178         for (j--; j >= 0; j--)
 179                 bpf_link__destroy(links[j]);
 180
 181         bpf_object__close(obj);
 182         return 0;
 183 }