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