samples/bpf/trace_event_user.c

   1 /* Copyright (c) 2016 Facebook
   2  *
   3  * This program is free software; you can redistribute it and/or
   4  * modify it under the terms of version 2 of the GNU General Public
   5  * License as published by the Free Software Foundation.
   6  */
   7 #include <stdio.h>
   8 #include <unistd.h>
   9 #include <stdlib.h>
  10 #include <stdbool.h>
  11 #include <string.h>
  12 #include <fcntl.h>
  13 #include <poll.h>
  14 #include <sys/ioctl.h>
  15 #include <linux/perf_event.h>
  16 #include <linux/bpf.h>
  17 #include <signal.h>
  18 #include <assert.h>
  19 #include <errno.h>
  20 #include <sys/resource.h>
  21 #include "libbpf.h"
  22 #include "bpf_load.h"
  23 #include "perf-sys.h"
  24
  25 #define SAMPLE_FREQ 50
  26
  27 static bool sys_read_seen, sys_write_seen;
  28
  29 static void print_ksym(__u64 addr)
  30 {
  31         struct ksym *sym;
  32
  33         if (!addr)
  34                 return;
  35         sym = ksym_search(addr);
  36         printf("%s;", sym->name);
  37         if (!strcmp(sym->name, "sys_read"))
  38                 sys_read_seen = true;
  39         else if (!strcmp(sym->name, "sys_write"))
  40                 sys_write_seen = true;
  41 }
  42
  43 static void print_addr(__u64 addr)
  44 {
  45         if (!addr)
  46                 return;
  47         printf("%llx;", addr);
  48 }
  49
  50 #define TASK_COMM_LEN 16
  51
  52 struct key_t {
  53         char comm[TASK_COMM_LEN];
  54         __u32 kernstack;
  55         __u32 userstack;
  56 };
  57
  58 static void print_stack(struct key_t *key, __u64 count)
  59 {
  60         __u64 ip[PERF_MAX_STACK_DEPTH] = {};
  61         static bool warned;
  62         int i;
  63
  64         printf("%3lld %s;", count, key->comm);
  65         if (bpf_map_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) {
  66                 printf("---;");
  67         } else {
  68                 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
  69                         print_ksym(ip[i]);
  70         }
  71         printf("-;");
  72         if (bpf_map_lookup_elem(map_fd[1], &key->userstack, ip) != 0) {
  73                 printf("---;");
  74         } else {
  75                 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
  76                         print_addr(ip[i]);
  77         }
  78         if (count < 6)
  79                 printf("\r");
  80         else
  81                 printf("\n");
  82
  83         if (key->kernstack == -EEXIST && !warned) {
  84                 printf("stackmap collisions seen. Consider increasing size\n");
  85                 warned = true;
  86         } else if ((int)key->kernstack < 0 && (int)key->userstack < 0) {
  87                 printf("err stackid %d %d\n", key->kernstack, key->userstack);
  88         }
  89 }
  90
  91 static void int_exit(int sig)
  92 {
  93         kill(0, SIGKILL);
  94         exit(0);
  95 }
  96
  97 static void print_stacks(void)
  98 {
  99         struct key_t key = {}, next_key;
 100         __u64 value;
 101         __u32 stackid = 0, next_id;
 102         int fd = map_fd[0], stack_map = map_fd[1];
 103
 104         sys_read_seen = sys_write_seen = false;
 105         while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
 106                 bpf_map_lookup_elem(fd, &next_key, &value);
 107                 print_stack(&next_key, value);
 108                 bpf_map_delete_elem(fd, &next_key);
 109                 key = next_key;
 110         }
 111         printf("\n");
 112         if (!sys_read_seen || !sys_write_seen) {
 113                 printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n");
 114                 int_exit(0);
 115         }
 116
 117         /* clear stack map */
 118         while (bpf_map_get_next_key(stack_map, &stackid, &next_id) == 0) {
 119                 bpf_map_delete_elem(stack_map, &next_id);
 120                 stackid = next_id;
 121         }
 122 }
 123
 124 static void test_perf_event_all_cpu(struct perf_event_attr *attr)
 125 {
 126         int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 127         int *pmu_fd = malloc(nr_cpus * sizeof(int));
 128         int i, error = 0;
 129
 130         /* system wide perf event, no need to inherit */
 131         attr->inherit = 0;
 132
 133         /* open perf_event on all cpus */
 134         for (i = 0; i < nr_cpus; i++) {
 135                 pmu_fd[i] = sys_perf_event_open(attr, -1, i, -1, 0);
 136                 if (pmu_fd[i] < 0) {
 137                         printf("sys_perf_event_open failed\n");
 138                         error = 1;
 139                         goto all_cpu_err;
 140                 }
 141                 assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
 142                 assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
 143         }
 144         system("dd if=/dev/zero of=/dev/null count=5000k status=none");
 145         print_stacks();
 146 all_cpu_err:
 147         for (i--; i >= 0; i--) {
 148                 ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
 149                 close(pmu_fd[i]);
 150         }
 151         free(pmu_fd);
 152         if (error)
 153                 int_exit(0);
 154 }
 155
 156 static void test_perf_event_task(struct perf_event_attr *attr)
 157 {
 158         int pmu_fd;
 159
 160         /* per task perf event, enable inherit so the "dd ..." command can be traced properly.
 161          * Enabling inherit will cause bpf_perf_prog_read_time helper failure.
 162          */
 163         attr->inherit = 1;
 164
 165         /* open task bound event */
 166         pmu_fd = sys_perf_event_open(attr, 0, -1, -1, 0);
 167         if (pmu_fd < 0) {
 168                 printf("sys_perf_event_open failed\n");
 169                 int_exit(0);
 170         }
 171         assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
 172         assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
 173         system("dd if=/dev/zero of=/dev/null count=5000k status=none");
 174         print_stacks();
 175         ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
 176         close(pmu_fd);
 177 }
 178
 179 static void test_bpf_perf_event(void)
 180 {
 181         struct perf_event_attr attr_type_hw = {
 182                 .sample_freq = SAMPLE_FREQ,
 183                 .freq = 1,
 184                 .type = PERF_TYPE_HARDWARE,
 185                 .config = PERF_COUNT_HW_CPU_CYCLES,
 186         };
 187         struct perf_event_attr attr_type_sw = {
 188                 .sample_freq = SAMPLE_FREQ,
 189                 .freq = 1,
 190                 .type = PERF_TYPE_SOFTWARE,
 191                 .config = PERF_COUNT_SW_CPU_CLOCK,
 192         };
 193         struct perf_event_attr attr_hw_cache_l1d = {
 194                 .sample_freq = SAMPLE_FREQ,
 195                 .freq = 1,
 196                 .type = PERF_TYPE_HW_CACHE,
 197                 .config =
 198                         PERF_COUNT_HW_CACHE_L1D |
 199                         (PERF_COUNT_HW_CACHE_OP_READ << 8) |
 200                         (PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
 201         };
 202         struct perf_event_attr attr_hw_cache_branch_miss = {
 203                 .sample_freq = SAMPLE_FREQ,
 204                 .freq = 1,
 205                 .type = PERF_TYPE_HW_CACHE,
 206                 .config =
 207                         PERF_COUNT_HW_CACHE_BPU |
 208                         (PERF_COUNT_HW_CACHE_OP_READ << 8) |
 209                         (PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
 210         };
 211         struct perf_event_attr attr_type_raw = {
 212                 .sample_freq = SAMPLE_FREQ,
 213                 .freq = 1,
 214                 .type = PERF_TYPE_RAW,
 215                 /* Intel Instruction Retired */
 216                 .config = 0xc0,
 217         };
 218
 219         printf("Test HW_CPU_CYCLES\n");
 220         test_perf_event_all_cpu(&attr_type_hw);
 221         test_perf_event_task(&attr_type_hw);
 222
 223         printf("Test SW_CPU_CLOCK\n");
 224         test_perf_event_all_cpu(&attr_type_sw);
 225         test_perf_event_task(&attr_type_sw);
 226
 227         printf("Test HW_CACHE_L1D\n");
 228         test_perf_event_all_cpu(&attr_hw_cache_l1d);
 229         test_perf_event_task(&attr_hw_cache_l1d);
 230
 231         printf("Test HW_CACHE_BPU\n");
 232         test_perf_event_all_cpu(&attr_hw_cache_branch_miss);
 233         test_perf_event_task(&attr_hw_cache_branch_miss);
 234
 235         printf("Test Instruction Retired\n");
 236         test_perf_event_all_cpu(&attr_type_raw);
 237         test_perf_event_task(&attr_type_raw);
 238
 239         printf("*** PASS ***\n");
 240 }
 241
 242
 243 int main(int argc, char **argv)
 244 {
 245         struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 246         char filename[256];
 247
 248         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 249         setrlimit(RLIMIT_MEMLOCK, &r);
 250
 251         signal(SIGINT, int_exit);
 252         signal(SIGTERM, int_exit);
 253
 254         if (load_kallsyms()) {
 255                 printf("failed to process /proc/kallsyms\n");
 256                 return 1;
 257         }
 258
 259         if (load_bpf_file(filename)) {
 260                 printf("%s", bpf_log_buf);
 261                 return 2;
 262         }
 263
 264         if (fork() == 0) {
 265                 read_trace_pipe();
 266                 return 0;
 267         }
 268         test_bpf_perf_event();
 269         int_exit(0);
 270         return 0;
 271 }