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 #include <sys/resource.h>
  11
  12 #include <bpf/bpf.h>
  13 #include <bpf/libbpf.h>
  14 #include "bpf_util.h"
  15
  16 #define SLOTS 100
  17
  18 static void clear_stats(int fd)
  19 {
  20         unsigned int nr_cpus = bpf_num_possible_cpus();
  21         __u64 values[nr_cpus];
  22         __u32 key;
  23
  24         memset(values, 0, sizeof(values));
  25         for (key = 0; key < SLOTS; key++)
  26                 bpf_map_update_elem(fd, &key, values, BPF_ANY);
  27 }
  28
  29 const char *color[] = {
  30         "\033[48;5;255m",
  31         "\033[48;5;252m",
  32         "\033[48;5;250m",
  33         "\033[48;5;248m",
  34         "\033[48;5;246m",
  35         "\033[48;5;244m",
  36         "\033[48;5;242m",
  37         "\033[48;5;240m",
  38         "\033[48;5;238m",
  39         "\033[48;5;236m",
  40         "\033[48;5;234m",
  41         "\033[48;5;232m",
  42 };
  43 const int num_colors = ARRAY_SIZE(color);
  44
  45 const char nocolor[] = "\033[00m";
  46
  47 const char *sym[] = {
  48         " ",
  49         " ",
  50         ".",
  51         ".",
  52         "*",
  53         "*",
  54         "o",
  55         "o",
  56         "O",
  57         "O",
  58         "#",
  59         "#",
  60 };
  61
  62 bool full_range = false;
  63 bool text_only = false;
  64
  65 static void print_banner(void)
  66 {
  67         if (full_range)
  68                 printf("|1ns     |10ns     |100ns    |1us      |10us     |100us"
  69                        "    |1ms      |10ms     |100ms    |1s       |10s\n");
  70         else
  71                 printf("|1us      |10us     |100us    |1ms      |10ms     "
  72                        "|100ms    |1s       |10s\n");
  73 }
  74
  75 static void print_hist(int fd)
  76 {
  77         unsigned int nr_cpus = bpf_num_possible_cpus();
  78         __u64 total_events = 0;
  79         long values[nr_cpus];
  80         __u64 max_cnt = 0;
  81         __u64 cnt[SLOTS];
  82         __u64 value;
  83         __u32 key;
  84         int i;
  85
  86         for (key = 0; key < SLOTS; key++) {
  87                 bpf_map_lookup_elem(fd, &key, values);
  88                 value = 0;
  89                 for (i = 0; i < nr_cpus; i++)
  90                         value += values[i];
  91                 cnt[key] = value;
  92                 total_events += value;
  93                 if (value > max_cnt)
  94                         max_cnt = value;
  95         }
  96         clear_stats(fd);
  97         for (key = full_range ? 0 : 29; key < SLOTS; key++) {
  98                 int c = num_colors * cnt[key] / (max_cnt + 1);
  99
 100                 if (text_only)
 101                         printf("%s", sym[c]);
 102                 else
 103                         printf("%s %s", color[c], nocolor);
 104         }
 105         printf(" # %lld\n", total_events);
 106 }
 107
 108 int main(int ac, char **argv)
 109 {
 110         struct bpf_link *links[2];
 111         struct bpf_program *prog;
 112         struct bpf_object *obj;
 113         char filename[256];
 114         int map_fd, i, j = 0;
 115
 116         for (i = 1; i < ac; i++) {
 117                 if (strcmp(argv[i], "-a") == 0) {
 118                         full_range = true;
 119                 } else if (strcmp(argv[i], "-t") == 0) {
 120                         text_only = true;
 121                 } else if (strcmp(argv[i], "-h") == 0) {
 122                         printf("Usage:\n"
 123                                "  -a display wider latency range\n"
 124                                "  -t text only\n");
 125                         return 1;
 126                 }
 127         }
 128
 129         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 130         obj = bpf_object__open_file(filename, NULL);
 131         if (libbpf_get_error(obj)) {
 132                 fprintf(stderr, "ERROR: opening BPF object file failed\n");
 133                 return 0;
 134         }
 135
 136         /* load BPF program */
 137         if (bpf_object__load(obj)) {
 138                 fprintf(stderr, "ERROR: loading BPF object file failed\n");
 139                 goto cleanup;
 140         }
 141
 142         map_fd = bpf_object__find_map_fd_by_name(obj, "lat_map");
 143         if (map_fd < 0) {
 144                 fprintf(stderr, "ERROR: finding a map in obj file failed\n");
 145                 goto cleanup;
 146         }
 147
 148         bpf_object__for_each_program(prog, obj) {
 149                 links[j] = bpf_program__attach(prog);
 150                 if (libbpf_get_error(links[j])) {
 151                         fprintf(stderr, "ERROR: bpf_program__attach failed\n");
 152                         links[j] = NULL;
 153                         goto cleanup;
 154                 }
 155                 j++;
 156         }
 157
 158         printf("  heatmap of IO latency\n");
 159         if (text_only)
 160                 printf("  %s", sym[num_colors - 1]);
 161         else
 162                 printf("  %s %s", color[num_colors - 1], nocolor);
 163         printf(" - many events with this latency\n");
 164
 165         if (text_only)
 166                 printf("  %s", sym[0]);
 167         else
 168                 printf("  %s %s", color[0], nocolor);
 169         printf(" - few events\n");
 170
 171         for (i = 0; ; i++) {
 172                 if (i % 20 == 0)
 173                         print_banner();
 174                 print_hist(map_fd);
 175                 sleep(2);
 176         }
 177
 178 cleanup:
 179         for (j--; j >= 0; j--)
 180                 bpf_link__destroy(links[j]);
 181
 182         bpf_object__close(obj);
 183         return 0;
 184 }