libust/ltt-ring-buffer-client.h

   1 /*
   2  * ltt-ring-buffer-client.h
   3  *
   4  * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng lib ring buffer client template.
   7  *
   8  * Dual LGPL v2.1/GPL v2 license.
   9  */
  10
  11 #include <stdint.h>
  12 #include <ust/lttng-events.h>
  13 #include "ust/bitfield.h"
  14 #include "ust/clock.h"
  15 #include "ltt-tracer.h"
  16 #include "../libringbuffer/frontend_types.h"
  17
  18 /*
  19  * Keep the natural field alignment for _each field_ within this structure if
  20  * you ever add/remove a field from this header. Packed attribute is not used
  21  * because gcc generates poor code on at least powerpc and mips. Don't ever
  22  * let gcc add padding between the structure elements.
  23  */
  24
  25 struct packet_header {
  26         /* Trace packet header */
  27         uint32_t magic;                 /*
  28                                          * Trace magic number.
  29                                          * contains endianness information.
  30                                          */
  31         uint8_t uuid[16];
  32         uint32_t stream_id;
  33
  34         struct {
  35                 /* Stream packet context */
  36                 uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
  37                 uint64_t timestamp_end;         /* Cycle count at subbuffer end */
  38                 uint32_t events_discarded;      /*
  39                                                  * Events lost in this subbuffer since
  40                                                  * the beginning of the trace.
  41                                                  * (may overflow)
  42                                                  */
  43                 uint32_t content_size;          /* Size of data in subbuffer */
  44                 uint32_t packet_size;           /* Subbuffer size (include padding) */
  45                 uint32_t cpu_id;                /* CPU id associated with stream */
  46                 uint8_t header_end;             /* End of header */
  47         } ctx;
  48 };
  49
  50
  51 static inline notrace u64 lib_ring_buffer_clock_read(struct channel *chan)
  52 {
  53         return trace_clock_read64();
  54 }
  55
  56 static inline
  57 size_t ctx_get_size(size_t offset, struct lttng_ctx *ctx)
  58 {
  59         int i;
  60         size_t orig_offset = offset;
  61
  62         if (likely(!ctx))
  63                 return 0;
  64         for (i = 0; i < ctx->nr_fields; i++)
  65                 offset += ctx->fields[i].get_size(offset);
  66         return offset - orig_offset;
  67 }
  68
  69 static inline
  70 void ctx_record(struct lib_ring_buffer_ctx *bufctx,
  71                 struct ltt_channel *chan,
  72                 struct lttng_ctx *ctx)
  73 {
  74         int i;
  75
  76         if (likely(!ctx))
  77                 return;
  78         for (i = 0; i < ctx->nr_fields; i++)
  79                 ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
  80 }
  81
  82 /*
  83  * record_header_size - Calculate the header size and padding necessary.
  84  * @config: ring buffer instance configuration
  85  * @chan: channel
  86  * @offset: offset in the write buffer
  87  * @pre_header_padding: padding to add before the header (output)
  88  * @ctx: reservation context
  89  *
  90  * Returns the event header size (including padding).
  91  *
  92  * The payload must itself determine its own alignment from the biggest type it
  93  * contains.
  94  */
  95 static __inline__
  96 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
  97                                  struct channel *chan, size_t offset,
  98                                  size_t *pre_header_padding,
  99                                  struct lib_ring_buffer_ctx *ctx)
 100 {
 101         struct ltt_channel *ltt_chan = channel_get_private(chan);
 102         struct ltt_event *event = ctx->priv;
 103         size_t orig_offset = offset;
 104         size_t padding;
 105
 106         switch (ltt_chan->header_type) {
 107         case 1: /* compact */
 108                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 109                 offset += padding;
 110                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {
 111                         offset += sizeof(uint32_t);     /* id and timestamp */
 112                 } else {
 113                         /* Minimum space taken by 5-bit id */
 114                         offset += sizeof(uint8_t);
 115                         /* Align extended struct on largest member */
 116                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 117                         offset += sizeof(uint32_t);     /* id */
 118                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 119                         offset += sizeof(uint64_t);     /* timestamp */
 120                 }
 121                 break;
 122         case 2: /* large */
 123                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint16_t));
 124                 offset += padding;
 125                 offset += sizeof(uint16_t);
 126                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {
 127                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 128                         offset += sizeof(uint32_t);     /* timestamp */
 129                 } else {
 130                         /* Align extended struct on largest member */
 131                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 132                         offset += sizeof(uint32_t);     /* id */
 133                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 134                         offset += sizeof(uint64_t);     /* timestamp */
 135                 }
 136                 break;
 137         default:
 138                 padding = 0;
 139                 WARN_ON_ONCE(1);
 140         }
 141         offset += ctx_get_size(offset, event->ctx);
 142         offset += ctx_get_size(offset, ltt_chan->ctx);
 143
 144         *pre_header_padding = padding;
 145         return offset - orig_offset;
 146 }
 147
 148 #include "../libringbuffer/api.h"
 149
 150 static
 151 void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,
 152                                  struct lib_ring_buffer_ctx *ctx,
 153                                  uint32_t event_id);
 154
 155 /*
 156  * ltt_write_event_header
 157  *
 158  * Writes the event header to the offset (already aligned on 32-bits).
 159  *
 160  * @config: ring buffer instance configuration
 161  * @ctx: reservation context
 162  * @event_id: event ID
 163  */
 164 static __inline__
 165 void ltt_write_event_header(const struct lib_ring_buffer_config *config,
 166                             struct lib_ring_buffer_ctx *ctx,
 167                             uint32_t event_id)
 168 {
 169         struct ltt_channel *ltt_chan = channel_get_private(ctx->chan);
 170         struct ltt_event *event = ctx->priv;
 171
 172         if (unlikely(ctx->rflags))
 173                 goto slow_path;
 174
 175         switch (ltt_chan->header_type) {
 176         case 1: /* compact */
 177         {
 178                 uint32_t id_time = 0;
 179
 180                 bt_bitfield_write(&id_time, uint32_t, 0, 5, event_id);
 181                 bt_bitfield_write(&id_time, uint32_t, 5, 27, ctx->tsc);
 182                 lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 183                 break;
 184         }
 185         case 2: /* large */
 186         {
 187                 uint32_t timestamp = (uint32_t) ctx->tsc;
 188                 uint16_t id = event_id;
 189
 190                 lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 191                 lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 192                 lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 193                 break;
 194         }
 195         default:
 196                 WARN_ON_ONCE(1);
 197         }
 198
 199         ctx_record(ctx, ltt_chan, ltt_chan->ctx);
 200         ctx_record(ctx, ltt_chan, event->ctx);
 201
 202         return;
 203
 204 slow_path:
 205         ltt_write_event_header_slow(config, ctx, event_id);
 206 }
 207
 208 static
 209 void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,
 210                                  struct lib_ring_buffer_ctx *ctx,
 211                                  uint32_t event_id)
 212 {
 213         struct ltt_channel *ltt_chan = channel_get_private(ctx->chan);
 214         struct ltt_event *event = ctx->priv;
 215
 216         switch (ltt_chan->header_type) {
 217         case 1: /* compact */
 218                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {
 219                         uint32_t id_time = 0;
 220
 221                         bt_bitfield_write(&id_time, uint32_t, 0, 5, event_id);
 222                         bt_bitfield_write(&id_time, uint32_t, 5, 27, ctx->tsc);
 223                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 224                 } else {
 225                         uint8_t id = 0;
 226                         uint64_t timestamp = ctx->tsc;
 227
 228                         bt_bitfield_write(&id, uint8_t, 0, 5, 31);
 229                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 230                         /* Align extended struct on largest member */
 231                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 232                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 233                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 234                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 235                 }
 236                 break;
 237         case 2: /* large */
 238         {
 239                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {
 240                         uint32_t timestamp = (uint32_t) ctx->tsc;
 241                         uint16_t id = event_id;
 242
 243                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 244                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 245                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 246                 } else {
 247                         uint16_t id = 65535;
 248                         uint64_t timestamp = ctx->tsc;
 249
 250                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 251                         /* Align extended struct on largest member */
 252                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 253                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 254                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 255                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 256                 }
 257                 break;
 258         }
 259         default:
 260                 WARN_ON_ONCE(1);
 261         }
 262         ctx_record(ctx, ltt_chan, ltt_chan->ctx);
 263         ctx_record(ctx, ltt_chan, event->ctx);
 264 }
 265
 266 static const struct lib_ring_buffer_config client_config;
 267
 268 static u64 client_ring_buffer_clock_read(struct channel *chan)
 269 {
 270         return lib_ring_buffer_clock_read(chan);
 271 }
 272
 273 static
 274 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
 275                                  struct channel *chan, size_t offset,
 276                                  size_t *pre_header_padding,
 277                                  struct lib_ring_buffer_ctx *ctx)
 278 {
 279         return record_header_size(config, chan, offset,
 280                                   pre_header_padding, ctx);
 281 }
 282
 283 /**
 284  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 285  *
 286  * Return header size without padding after the structure. Don't use packed
 287  * structure because gcc generates inefficient code on some architectures
 288  * (powerpc, mips..)
 289  */
 290 static size_t client_packet_header_size(void)
 291 {
 292         return offsetof(struct packet_header, ctx.header_end);
 293 }
 294
 295 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
 296                                 unsigned int subbuf_idx,
 297                                 struct shm_handle *handle)
 298 {
 299         struct channel *chan = shmp(handle, buf->backend.chan);
 300         struct packet_header *header =
 301                 (struct packet_header *)
 302                         lib_ring_buffer_offset_address(&buf->backend,
 303                                 subbuf_idx * chan->backend.subbuf_size,
 304                                 handle);
 305         struct ltt_channel *ltt_chan = channel_get_private(chan);
 306         struct ltt_session *session = ltt_chan->session;
 307
 308         header->magic = CTF_MAGIC_NUMBER;
 309         memcpy(header->uuid, session->uuid, sizeof(session->uuid));
 310         header->stream_id = ltt_chan->id;
 311         header->ctx.timestamp_begin = tsc;
 312         header->ctx.timestamp_end = 0;
 313         header->ctx.events_discarded = 0;
 314         header->ctx.content_size = 0xFFFFFFFF; /* for debugging */
 315         header->ctx.packet_size = 0xFFFFFFFF;
 316         header->ctx.cpu_id = buf->backend.cpu;
 317 }
 318
 319 /*
 320  * offset is assumed to never be 0 here : never deliver a completely empty
 321  * subbuffer. data_size is between 1 and subbuf_size.
 322  */
 323 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 324                               unsigned int subbuf_idx, unsigned long data_size,
 325                               struct shm_handle *handle)
 326 {
 327         struct channel *chan = shmp(handle, buf->backend.chan);
 328         struct packet_header *header =
 329                 (struct packet_header *)
 330                         lib_ring_buffer_offset_address(&buf->backend,
 331                                 subbuf_idx * chan->backend.subbuf_size,
 332                                 handle);
 333         unsigned long records_lost = 0;
 334
 335         header->ctx.timestamp_end = tsc;
 336         header->ctx.content_size = data_size * CHAR_BIT;        /* in bits */
 337         header->ctx.packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 338         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 339         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 340         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 341         header->ctx.events_discarded = records_lost;
 342 }
 343
 344 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 345                                 int cpu, const char *name, struct shm_handle *handle)
 346 {
 347         return 0;
 348 }
 349
 350 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu, struct shm_handle *handle)
 351 {
 352 }
 353
 354 static const struct lib_ring_buffer_config client_config = {
 355         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 356         .cb.record_header_size = client_record_header_size,
 357         .cb.subbuffer_header_size = client_packet_header_size,
 358         .cb.buffer_begin = client_buffer_begin,
 359         .cb.buffer_end = client_buffer_end,
 360         .cb.buffer_create = client_buffer_create,
 361         .cb.buffer_finalize = client_buffer_finalize,
 362
 363         .tsc_bits = 32,
 364         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 365         .sync = RING_BUFFER_SYNC_GLOBAL,
 366         .mode = RING_BUFFER_MODE_TEMPLATE,
 367         .backend = RING_BUFFER_PAGE,
 368         .output = RING_BUFFER_MMAP,
 369         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 370         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 371         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 372 };
 373
 374 static
 375 struct ltt_channel *_channel_create(const char *name,
 376                                 struct ltt_channel *ltt_chan, void *buf_addr,
 377                                 size_t subbuf_size, size_t num_subbuf,
 378                                 unsigned int switch_timer_interval,
 379                                 unsigned int read_timer_interval)
 380 {
 381         ltt_chan->handle = channel_create(&client_config, name, ltt_chan, buf_addr,
 382                               subbuf_size, num_subbuf, switch_timer_interval,
 383                               read_timer_interval);
 384         ltt_chan->chan = shmp(handle, handle->chan);
 385         return ltt_chan;
 386 }
 387
 388 static
 389 void ltt_channel_destroy(struct ltt_channel *ltt_chan)
 390 {
 391         channel_destroy(ltt_chan->chan, ltt_chan->handle);
 392 }
 393
 394 static
 395 struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan,
 396                                              struct shm_handle *handle)
 397 {
 398         struct lib_ring_buffer *buf;
 399         int cpu;
 400
 401         for_each_channel_cpu(cpu, chan) {
 402                 buf = channel_get_ring_buffer(&client_config, chan, cpu, handle);
 403                 if (!lib_ring_buffer_open_read(buf, handle))
 404                         return buf;
 405         }
 406         return NULL;
 407 }
 408
 409 static
 410 void ltt_buffer_read_close(struct lib_ring_buffer *buf,
 411                            struct shm_handle *handle)
 412 {
 413         lib_ring_buffer_release_read(buf, handle);
 414 }
 415
 416 static
 417 int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx,
 418                       uint32_t event_id)
 419 {
 420         struct ltt_channel *ltt_chan = channel_get_private(ctx->chan);
 421         int ret, cpu;
 422
 423         cpu = lib_ring_buffer_get_cpu(&client_config);
 424         if (cpu < 0)
 425                 return -EPERM;
 426         ctx->cpu = cpu;
 427
 428         switch (ltt_chan->header_type) {
 429         case 1: /* compact */
 430                 if (event_id > 30)
 431                         ctx->rflags |= LTT_RFLAG_EXTENDED;
 432                 break;
 433         case 2: /* large */
 434                 if (event_id > 65534)
 435                         ctx->rflags |= LTT_RFLAG_EXTENDED;
 436                 break;
 437         default:
 438                 WARN_ON_ONCE(1);
 439         }
 440
 441         ret = lib_ring_buffer_reserve(&client_config, ctx);
 442         if (ret)
 443                 goto put;
 444         ltt_write_event_header(&client_config, ctx, event_id);
 445         return 0;
 446 put:
 447         lib_ring_buffer_put_cpu(&client_config);
 448         return ret;
 449 }
 450
 451 static
 452 void ltt_event_commit(struct lib_ring_buffer_ctx *ctx)
 453 {
 454         lib_ring_buffer_commit(&client_config, ctx);
 455         lib_ring_buffer_put_cpu(&client_config);
 456 }
 457
 458 static
 459 void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 460                      size_t len)
 461 {
 462         lib_ring_buffer_write(&client_config, ctx, src, len);
 463 }
 464
 465 #if 0
 466 static
 467 wait_queue_head_t *ltt_get_reader_wait_queue(struct channel *chan)
 468 {
 469         return &chan->read_wait;
 470 }
 471
 472 static
 473 wait_queue_head_t *ltt_get_hp_wait_queue(struct channel *chan)
 474 {
 475         return &chan->hp_wait;
 476 }
 477 #endif //0
 478
 479 static
 480 int ltt_is_finalized(struct channel *chan)
 481 {
 482         return lib_ring_buffer_channel_is_finalized(chan);
 483 }
 484
 485 static
 486 int ltt_is_disabled(struct channel *chan)
 487 {
 488         return lib_ring_buffer_channel_is_disabled(chan);
 489 }
 490
 491 static struct ltt_transport ltt_relay_transport = {
 492         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 493         .ops = {
 494                 .channel_create = _channel_create,
 495                 .channel_destroy = ltt_channel_destroy,
 496                 .buffer_read_open = ltt_buffer_read_open,
 497                 .buffer_read_close = ltt_buffer_read_close,
 498                 .event_reserve = ltt_event_reserve,
 499                 .event_commit = ltt_event_commit,
 500                 .event_write = ltt_event_write,
 501                 .packet_avail_size = NULL,      /* Would be racy anyway */
 502                 //.get_reader_wait_queue = ltt_get_reader_wait_queue,
 503                 //.get_hp_wait_queue = ltt_get_hp_wait_queue,
 504                 .is_finalized = ltt_is_finalized,
 505                 .is_disabled = ltt_is_disabled,
 506         },
 507 };
 508
 509 static
 510 void __attribute__((constructor)) ltt_ring_buffer_client_init(void)
 511 {
 512         DBG("LTT : ltt ring buffer client init\n");
 513         ltt_transport_register(&ltt_relay_transport);
 514 }
 515
 516 static
 517 void __attribute__((destructor)) ltt_ring_buffer_client_exit(void)
 518 {
 519         DBG("LTT : ltt ring buffer client exit\n");
 520         ltt_transport_unregister(&ltt_relay_transport);
 521 }