tools/bpf/bpftool/map_perf_ring.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (C) 2018 Netronome Systems, Inc. */
   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 <errno.h>
   8 #include <fcntl.h>
   9 #include <libbpf.h>
  10 #include <poll.h>
  11 #include <signal.h>
  12 #include <stdbool.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <time.h>
  17 #include <unistd.h>
  18 #include <linux/bpf.h>
  19 #include <linux/perf_event.h>
  20 #include <sys/ioctl.h>
  21 #include <sys/mman.h>
  22 #include <sys/syscall.h>
  23
  24 #include <bpf.h>
  25 #include <perf-sys.h>
  26
  27 #include "main.h"
  28
  29 #define MMAP_PAGE_CNT   16
  30
  31 static bool stop;
  32
  33 struct event_ring_info {
  34         int fd;
  35         int key;
  36         unsigned int cpu;
  37         void *mem;
  38 };
  39
  40 struct perf_event_sample {
  41         struct perf_event_header header;
  42         u64 time;
  43         __u32 size;
  44         unsigned char data[];
  45 };
  46
  47 static void int_exit(int signo)
  48 {
  49         fprintf(stderr, "Stopping...\n");
  50         stop = true;
  51 }
  52
  53 static enum bpf_perf_event_ret
  54 print_bpf_output(struct perf_event_header *event, void *private_data)
  55 {
  56         struct perf_event_sample *e = container_of(event, struct perf_event_sample,
  57                                                    header);
  58         struct event_ring_info *ring = private_data;
  59         struct {
  60                 struct perf_event_header header;
  61                 __u64 id;
  62                 __u64 lost;
  63         } *lost = (typeof(lost))event;
  64
  65         if (json_output) {
  66                 jsonw_start_object(json_wtr);
  67                 jsonw_name(json_wtr, "type");
  68                 jsonw_uint(json_wtr, e->header.type);
  69                 jsonw_name(json_wtr, "cpu");
  70                 jsonw_uint(json_wtr, ring->cpu);
  71                 jsonw_name(json_wtr, "index");
  72                 jsonw_uint(json_wtr, ring->key);
  73                 if (e->header.type == PERF_RECORD_SAMPLE) {
  74                         jsonw_name(json_wtr, "timestamp");
  75                         jsonw_uint(json_wtr, e->time);
  76                         jsonw_name(json_wtr, "data");
  77                         print_data_json(e->data, e->size);
  78                 } else if (e->header.type == PERF_RECORD_LOST) {
  79                         jsonw_name(json_wtr, "lost");
  80                         jsonw_start_object(json_wtr);
  81                         jsonw_name(json_wtr, "id");
  82                         jsonw_uint(json_wtr, lost->id);
  83                         jsonw_name(json_wtr, "count");
  84                         jsonw_uint(json_wtr, lost->lost);
  85                         jsonw_end_object(json_wtr);
  86                 }
  87                 jsonw_end_object(json_wtr);
  88         } else {
  89                 if (e->header.type == PERF_RECORD_SAMPLE) {
  90                         printf("== @%lld.%09lld CPU: %d index: %d =====\n",
  91                                e->time / 1000000000ULL, e->time % 1000000000ULL,
  92                                ring->cpu, ring->key);
  93                         fprint_hex(stdout, e->data, e->size, " ");
  94                         printf("\n");
  95                 } else if (e->header.type == PERF_RECORD_LOST) {
  96                         printf("lost %lld events\n", lost->lost);
  97                 } else {
  98                         printf("unknown event type=%d size=%d\n",
  99                                e->header.type, e->header.size);
 100                 }
 101         }
 102
 103         return LIBBPF_PERF_EVENT_CONT;
 104 }
 105
 106 static void
 107 perf_event_read(struct event_ring_info *ring, void **buf, size_t *buf_len)
 108 {
 109         enum bpf_perf_event_ret ret;
 110
 111         ret = bpf_perf_event_read_simple(ring->mem,
 112                                          MMAP_PAGE_CNT * get_page_size(),
 113                                          get_page_size(), buf, buf_len,
 114                                          print_bpf_output, ring);
 115         if (ret != LIBBPF_PERF_EVENT_CONT) {
 116                 fprintf(stderr, "perf read loop failed with %d\n", ret);
 117                 stop = true;
 118         }
 119 }
 120
 121 static int perf_mmap_size(void)
 122 {
 123         return get_page_size() * (MMAP_PAGE_CNT + 1);
 124 }
 125
 126 static void *perf_event_mmap(int fd)
 127 {
 128         int mmap_size = perf_mmap_size();
 129         void *base;
 130
 131         base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 132         if (base == MAP_FAILED) {
 133                 p_err("event mmap failed: %s\n", strerror(errno));
 134                 return NULL;
 135         }
 136
 137         return base;
 138 }
 139
 140 static void perf_event_unmap(void *mem)
 141 {
 142         if (munmap(mem, perf_mmap_size()))
 143                 fprintf(stderr, "Can't unmap ring memory!\n");
 144 }
 145
 146 static int bpf_perf_event_open(int map_fd, int key, int cpu)
 147 {
 148         struct perf_event_attr attr = {
 149                 .sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_TIME,
 150                 .type = PERF_TYPE_SOFTWARE,
 151                 .config = PERF_COUNT_SW_BPF_OUTPUT,
 152         };
 153         int pmu_fd;
 154
 155         pmu_fd = sys_perf_event_open(&attr, -1, cpu, -1, 0);
 156         if (pmu_fd < 0) {
 157                 p_err("failed to open perf event %d for CPU %d", key, cpu);
 158                 return -1;
 159         }
 160
 161         if (bpf_map_update_elem(map_fd, &key, &pmu_fd, BPF_ANY)) {
 162                 p_err("failed to update map for event %d for CPU %d", key, cpu);
 163                 goto err_close;
 164         }
 165         if (ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0)) {
 166                 p_err("failed to enable event %d for CPU %d", key, cpu);
 167                 goto err_close;
 168         }
 169
 170         return pmu_fd;
 171
 172 err_close:
 173         close(pmu_fd);
 174         return -1;
 175 }
 176
 177 int do_event_pipe(int argc, char **argv)
 178 {
 179         int i, nfds, map_fd, index = -1, cpu = -1;
 180         struct bpf_map_info map_info = {};
 181         struct event_ring_info *rings;
 182         size_t tmp_buf_sz = 0;
 183         void *tmp_buf = NULL;
 184         struct pollfd *pfds;
 185         __u32 map_info_len;
 186         bool do_all = true;
 187
 188         map_info_len = sizeof(map_info);
 189         map_fd = map_parse_fd_and_info(&argc, &argv, &map_info, &map_info_len);
 190         if (map_fd < 0)
 191                 return -1;
 192
 193         if (map_info.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
 194                 p_err("map is not a perf event array");
 195                 goto err_close_map;
 196         }
 197
 198         while (argc) {
 199                 if (argc < 2) {
 200                         BAD_ARG();
 201                         goto err_close_map;
 202                 }
 203
 204                 if (is_prefix(*argv, "cpu")) {
 205                         char *endptr;
 206
 207                         NEXT_ARG();
 208                         cpu = strtoul(*argv, &endptr, 0);
 209                         if (*endptr) {
 210                                 p_err("can't parse %s as CPU ID", **argv);
 211                                 goto err_close_map;
 212                         }
 213
 214                         NEXT_ARG();
 215                 } else if (is_prefix(*argv, "index")) {
 216                         char *endptr;
 217
 218                         NEXT_ARG();
 219                         index = strtoul(*argv, &endptr, 0);
 220                         if (*endptr) {
 221                                 p_err("can't parse %s as index", **argv);
 222                                 goto err_close_map;
 223                         }
 224
 225                         NEXT_ARG();
 226                 } else {
 227                         BAD_ARG();
 228                         goto err_close_map;
 229                 }
 230
 231                 do_all = false;
 232         }
 233
 234         if (!do_all) {
 235                 if (index == -1 || cpu == -1) {
 236                         p_err("cpu and index must be specified together");
 237                         goto err_close_map;
 238                 }
 239
 240                 nfds = 1;
 241         } else {
 242                 nfds = min(get_possible_cpus(), map_info.max_entries);
 243                 cpu = 0;
 244                 index = 0;
 245         }
 246
 247         rings = calloc(nfds, sizeof(rings[0]));
 248         if (!rings)
 249                 goto err_close_map;
 250
 251         pfds = calloc(nfds, sizeof(pfds[0]));
 252         if (!pfds)
 253                 goto err_free_rings;
 254
 255         for (i = 0; i < nfds; i++) {
 256                 rings[i].cpu = cpu + i;
 257                 rings[i].key = index + i;
 258
 259                 rings[i].fd = bpf_perf_event_open(map_fd, rings[i].key,
 260                                                   rings[i].cpu);
 261                 if (rings[i].fd < 0)
 262                         goto err_close_fds_prev;
 263
 264                 rings[i].mem = perf_event_mmap(rings[i].fd);
 265                 if (!rings[i].mem)
 266                         goto err_close_fds_current;
 267
 268                 pfds[i].fd = rings[i].fd;
 269                 pfds[i].events = POLLIN;
 270         }
 271
 272         signal(SIGINT, int_exit);
 273         signal(SIGHUP, int_exit);
 274         signal(SIGTERM, int_exit);
 275
 276         if (json_output)
 277                 jsonw_start_array(json_wtr);
 278
 279         while (!stop) {
 280                 poll(pfds, nfds, 200);
 281                 for (i = 0; i < nfds; i++)
 282                         perf_event_read(&rings[i], &tmp_buf, &tmp_buf_sz);
 283         }
 284         free(tmp_buf);
 285
 286         if (json_output)
 287                 jsonw_end_array(json_wtr);
 288
 289         for (i = 0; i < nfds; i++) {
 290                 perf_event_unmap(rings[i].mem);
 291                 close(rings[i].fd);
 292         }
 293         free(pfds);
 294         free(rings);
 295         close(map_fd);
 296
 297         return 0;
 298
 299 err_close_fds_prev:
 300         while (i--) {
 301                 perf_event_unmap(rings[i].mem);
 302 err_close_fds_current:
 303                 close(rings[i].fd);
 304         }
 305         free(pfds);
 306 err_free_rings:
 307         free(rings);
 308 err_close_map:
 309         close(map_fd);
 310         return -1;
 311 }