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 #include "trace_helpers.h"
  25
  26 #define SAMPLE_FREQ 50
  27
  28 static bool sys_read_seen, sys_write_seen;
  29
  30 static void print_ksym(__u64 addr)
  31 {
  32         struct ksym *sym;
  33
  34         if (!addr)
  35                 return;
  36         sym = ksym_search(addr);
  37         if (!sym) {
  38                 printf("ksym not found. Is kallsyms loaded?\n");
  39                 return;
  40         }
  41
  42         printf("%s;", sym->name);
  43         if (!strcmp(sym->name, "sys_read"))
  44                 sys_read_seen = true;
  45         else if (!strcmp(sym->name, "sys_write"))
  46                 sys_write_seen = true;
  47 }
  48
  49 static void print_addr(__u64 addr)
  50 {
  51         if (!addr)
  52                 return;
  53         printf("%llx;", addr);
  54 }
  55
  56 #define TASK_COMM_LEN 16
  57
  58 struct key_t {
  59         char comm[TASK_COMM_LEN];
  60         __u32 kernstack;
  61         __u32 userstack;
  62 };
  63
  64 static void print_stack(struct key_t *key, __u64 count)
  65 {
  66         __u64 ip[PERF_MAX_STACK_DEPTH] = {};
  67         static bool warned;
  68         int i;
  69
  70         printf("%3lld %s;", count, key->comm);
  71         if (bpf_map_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) {
  72                 printf("---;");
  73         } else {
  74                 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
  75                         print_ksym(ip[i]);
  76         }
  77         printf("-;");
  78         if (bpf_map_lookup_elem(map_fd[1], &key->userstack, ip) != 0) {
  79                 printf("---;");
  80         } else {
  81                 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
  82                         print_addr(ip[i]);
  83         }
  84         if (count < 6)
  85                 printf("\r");
  86         else
  87                 printf("\n");
  88
  89         if (key->kernstack == -EEXIST && !warned) {
  90                 printf("stackmap collisions seen. Consider increasing size\n");
  91                 warned = true;
  92         } else if ((int)key->kernstack < 0 && (int)key->userstack < 0) {
  93                 printf("err stackid %d %d\n", key->kernstack, key->userstack);
  94         }
  95 }
  96
  97 static void int_exit(int sig)
  98 {
  99         kill(0, SIGKILL);
 100         exit(0);
 101 }
 102
 103 static void print_stacks(void)
 104 {
 105         struct key_t key = {}, next_key;
 106         __u64 value;
 107         __u32 stackid = 0, next_id;
 108         int fd = map_fd[0], stack_map = map_fd[1];
 109
 110         sys_read_seen = sys_write_seen = false;
 111         while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
 112                 bpf_map_lookup_elem(fd, &next_key, &value);
 113                 print_stack(&next_key, value);
 114                 bpf_map_delete_elem(fd, &next_key);
 115                 key = next_key;
 116         }
 117         printf("\n");
 118         if (!sys_read_seen || !sys_write_seen) {
 119                 printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n");
 120                 int_exit(0);
 121         }
 122
 123         /* clear stack map */
 124         while (bpf_map_get_next_key(stack_map, &stackid, &next_id) == 0) {
 125                 bpf_map_delete_elem(stack_map, &next_id);
 126                 stackid = next_id;
 127         }
 128 }
 129
 130 static inline int generate_load(void)
 131 {
 132         if (system("dd if=/dev/zero of=/dev/null count=5000k status=none") < 0) {
 133                 printf("failed to generate some load with dd: %s\n", strerror(errno));
 134                 return -1;
 135         }
 136
 137         return 0;
 138 }
 139
 140 static void test_perf_event_all_cpu(struct perf_event_attr *attr)
 141 {
 142         int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 143         int *pmu_fd = malloc(nr_cpus * sizeof(int));
 144         int i, error = 0;
 145
 146         /* system wide perf event, no need to inherit */
 147         attr->inherit = 0;
 148
 149         /* open perf_event on all cpus */
 150         for (i = 0; i < nr_cpus; i++) {
 151                 pmu_fd[i] = sys_perf_event_open(attr, -1, i, -1, 0);
 152                 if (pmu_fd[i] < 0) {
 153                         printf("sys_perf_event_open failed\n");
 154                         error = 1;
 155                         goto all_cpu_err;
 156                 }
 157                 assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
 158                 assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
 159         }
 160
 161         if (generate_load() < 0) {
 162                 error = 1;
 163                 goto all_cpu_err;
 164         }
 165         print_stacks();
 166 all_cpu_err:
 167         for (i--; i >= 0; i--) {
 168                 ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
 169                 close(pmu_fd[i]);
 170         }
 171         free(pmu_fd);
 172         if (error)
 173                 int_exit(0);
 174 }
 175
 176 static void test_perf_event_task(struct perf_event_attr *attr)
 177 {
 178         int pmu_fd, error = 0;
 179
 180         /* per task perf event, enable inherit so the "dd ..." command can be traced properly.
 181          * Enabling inherit will cause bpf_perf_prog_read_time helper failure.
 182          */
 183         attr->inherit = 1;
 184
 185         /* open task bound event */
 186         pmu_fd = sys_perf_event_open(attr, 0, -1, -1, 0);
 187         if (pmu_fd < 0) {
 188                 printf("sys_perf_event_open failed\n");
 189                 int_exit(0);
 190         }
 191         assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
 192         assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
 193
 194         if (generate_load() < 0) {
 195                 error = 1;
 196                 goto err;
 197         }
 198         print_stacks();
 199 err:
 200         ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
 201         close(pmu_fd);
 202         if (error)
 203                 int_exit(0);
 204 }
 205
 206 static void test_bpf_perf_event(void)
 207 {
 208         struct perf_event_attr attr_type_hw = {
 209                 .sample_freq = SAMPLE_FREQ,
 210                 .freq = 1,
 211                 .type = PERF_TYPE_HARDWARE,
 212                 .config = PERF_COUNT_HW_CPU_CYCLES,
 213         };
 214         struct perf_event_attr attr_type_sw = {
 215                 .sample_freq = SAMPLE_FREQ,
 216                 .freq = 1,
 217                 .type = PERF_TYPE_SOFTWARE,
 218                 .config = PERF_COUNT_SW_CPU_CLOCK,
 219         };
 220         struct perf_event_attr attr_hw_cache_l1d = {
 221                 .sample_freq = SAMPLE_FREQ,
 222                 .freq = 1,
 223                 .type = PERF_TYPE_HW_CACHE,
 224                 .config =
 225                         PERF_COUNT_HW_CACHE_L1D |
 226                         (PERF_COUNT_HW_CACHE_OP_READ << 8) |
 227                         (PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
 228         };
 229         struct perf_event_attr attr_hw_cache_branch_miss = {
 230                 .sample_freq = SAMPLE_FREQ,
 231                 .freq = 1,
 232                 .type = PERF_TYPE_HW_CACHE,
 233                 .config =
 234                         PERF_COUNT_HW_CACHE_BPU |
 235                         (PERF_COUNT_HW_CACHE_OP_READ << 8) |
 236                         (PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
 237         };
 238         struct perf_event_attr attr_type_raw = {
 239                 .sample_freq = SAMPLE_FREQ,
 240                 .freq = 1,
 241                 .type = PERF_TYPE_RAW,
 242                 /* Intel Instruction Retired */
 243                 .config = 0xc0,
 244         };
 245         struct perf_event_attr attr_type_raw_lock_load = {
 246                 .sample_freq = SAMPLE_FREQ,
 247                 .freq = 1,
 248                 .type = PERF_TYPE_RAW,
 249                 /* Intel MEM_UOPS_RETIRED.LOCK_LOADS */
 250                 .config = 0x21d0,
 251                 /* Request to record lock address from PEBS */
 252                 .sample_type = PERF_SAMPLE_ADDR,
 253                 /* Record address value requires precise event */
 254                 .precise_ip = 2,
 255         };
 256
 257         printf("Test HW_CPU_CYCLES\n");
 258         test_perf_event_all_cpu(&attr_type_hw);
 259         test_perf_event_task(&attr_type_hw);
 260
 261         printf("Test SW_CPU_CLOCK\n");
 262         test_perf_event_all_cpu(&attr_type_sw);
 263         test_perf_event_task(&attr_type_sw);
 264
 265         printf("Test HW_CACHE_L1D\n");
 266         test_perf_event_all_cpu(&attr_hw_cache_l1d);
 267         test_perf_event_task(&attr_hw_cache_l1d);
 268
 269         printf("Test HW_CACHE_BPU\n");
 270         test_perf_event_all_cpu(&attr_hw_cache_branch_miss);
 271         test_perf_event_task(&attr_hw_cache_branch_miss);
 272
 273         printf("Test Instruction Retired\n");
 274         test_perf_event_all_cpu(&attr_type_raw);
 275         test_perf_event_task(&attr_type_raw);
 276
 277         printf("Test Lock Load\n");
 278         test_perf_event_all_cpu(&attr_type_raw_lock_load);
 279         test_perf_event_task(&attr_type_raw_lock_load);
 280
 281         printf("*** PASS ***\n");
 282 }
 283
 284
 285 int main(int argc, char **argv)
 286 {
 287         struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 288         char filename[256];
 289
 290         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 291         setrlimit(RLIMIT_MEMLOCK, &r);
 292
 293         signal(SIGINT, int_exit);
 294         signal(SIGTERM, int_exit);
 295
 296         if (load_kallsyms()) {
 297                 printf("failed to process /proc/kallsyms\n");
 298                 return 1;
 299         }
 300
 301         if (load_bpf_file(filename)) {
 302                 printf("%s", bpf_log_buf);
 303                 return 2;
 304         }
 305
 306         if (fork() == 0) {
 307                 read_trace_pipe();
 308                 return 0;
 309         }
 310         test_bpf_perf_event();
 311         int_exit(0);
 312         return 0;
 313 }