| 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 <linux/module.h> |
| 12 | #include <linux/types.h> |
| 13 | #include "lib/bitfield.h" |
| 14 | #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */ |
| 15 | #include "wrapper/trace-clock.h" |
| 16 | #include "ltt-events.h" |
| 17 | #include "ltt-tracer.h" |
| 18 | #include "wrapper/ringbuffer/frontend_types.h" |
| 19 | |
| 20 | /* |
| 21 | * Keep the natural field alignment for _each field_ within this structure if |
| 22 | * you ever add/remove a field from this header. Packed attribute is not used |
| 23 | * because gcc generates poor code on at least powerpc and mips. Don't ever |
| 24 | * let gcc add padding between the structure elements. |
| 25 | */ |
| 26 | |
| 27 | struct packet_header { |
| 28 | /* Trace packet header */ |
| 29 | uint32_t magic; /* |
| 30 | * Trace magic number. |
| 31 | * contains endianness information. |
| 32 | */ |
| 33 | uint8_t uuid[16]; |
| 34 | uint32_t stream_id; |
| 35 | |
| 36 | struct { |
| 37 | /* Stream packet context */ |
| 38 | uint64_t timestamp_begin; /* Cycle count at subbuffer start */ |
| 39 | uint64_t timestamp_end; /* Cycle count at subbuffer end */ |
| 40 | uint32_t events_discarded; /* |
| 41 | * Events lost in this subbuffer since |
| 42 | * the beginning of the trace. |
| 43 | * (may overflow) |
| 44 | */ |
| 45 | uint32_t content_size; /* Size of data in subbuffer */ |
| 46 | uint32_t packet_size; /* Subbuffer size (include padding) */ |
| 47 | uint32_t cpu_id; /* CPU id associated with stream */ |
| 48 | uint8_t header_end; /* End of header */ |
| 49 | } ctx; |
| 50 | }; |
| 51 | |
| 52 | |
| 53 | static inline notrace u64 lib_ring_buffer_clock_read(struct channel *chan) |
| 54 | { |
| 55 | return trace_clock_read64(); |
| 56 | } |
| 57 | |
| 58 | /* |
| 59 | * record_header_size - Calculate the header size and padding necessary. |
| 60 | * @config: ring buffer instance configuration |
| 61 | * @chan: channel |
| 62 | * @offset: offset in the write buffer |
| 63 | * @data_size: size of the payload |
| 64 | * @pre_header_padding: padding to add before the header (output) |
| 65 | * @rflags: reservation flags |
| 66 | * @ctx: reservation context |
| 67 | * |
| 68 | * Returns the event header size (including padding). |
| 69 | * |
| 70 | * The payload must itself determine its own alignment from the biggest type it |
| 71 | * contains. |
| 72 | */ |
| 73 | static __inline__ |
| 74 | unsigned char record_header_size(const struct lib_ring_buffer_config *config, |
| 75 | struct channel *chan, size_t offset, |
| 76 | size_t data_size, size_t *pre_header_padding, |
| 77 | unsigned int rflags, |
| 78 | struct lib_ring_buffer_ctx *ctx) |
| 79 | { |
| 80 | struct ltt_channel *ltt_chan = channel_get_private(chan); |
| 81 | size_t orig_offset = offset; |
| 82 | size_t padding; |
| 83 | |
| 84 | switch (ltt_chan->header_type) { |
| 85 | case 1: /* compact */ |
| 86 | padding = lib_ring_buffer_align(offset, ltt_alignof(uint32_t)); |
| 87 | offset += padding; |
| 88 | if (!(rflags & RING_BUFFER_RFLAG_FULL_TSC)) { |
| 89 | offset += sizeof(uint32_t); /* id and timestamp */ |
| 90 | } else { |
| 91 | /* Minimum space taken by 5-bit id */ |
| 92 | offset += sizeof(uint8_t); |
| 93 | /* Align extended struct on largest member */ |
| 94 | offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); |
| 95 | offset += sizeof(uint32_t); /* id */ |
| 96 | offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); |
| 97 | offset += sizeof(uint64_t); /* timestamp */ |
| 98 | } |
| 99 | break; |
| 100 | case 2: /* large */ |
| 101 | padding = lib_ring_buffer_align(offset, ltt_alignof(uint16_t)); |
| 102 | offset += padding; |
| 103 | offset += sizeof(uint16_t); |
| 104 | if (!(rflags & RING_BUFFER_RFLAG_FULL_TSC)) { |
| 105 | offset += lib_ring_buffer_align(offset, ltt_alignof(uint32_t)); |
| 106 | offset += sizeof(uint32_t); /* timestamp */ |
| 107 | } else { |
| 108 | /* Align extended struct on largest member */ |
| 109 | offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); |
| 110 | offset += sizeof(uint32_t); /* id */ |
| 111 | offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); |
| 112 | offset += sizeof(uint64_t); /* timestamp */ |
| 113 | |
| 114 | } |
| 115 | break; |
| 116 | default: |
| 117 | WARN_ON(1); |
| 118 | } |
| 119 | |
| 120 | *pre_header_padding = padding; |
| 121 | return offset - orig_offset; |
| 122 | } |
| 123 | |
| 124 | #include "wrapper/ringbuffer/api.h" |
| 125 | |
| 126 | extern |
| 127 | void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config, |
| 128 | struct lib_ring_buffer_ctx *ctx, |
| 129 | u16 eID, u32 event_size); |
| 130 | |
| 131 | /* |
| 132 | * ltt_write_event_header |
| 133 | * |
| 134 | * Writes the event header to the offset (already aligned on 32-bits). |
| 135 | * |
| 136 | * @config: ring buffer instance configuration |
| 137 | * @ctx: reservation context |
| 138 | * @eID : event ID |
| 139 | * @event_size : size of the event, excluding the event header. |
| 140 | */ |
| 141 | static __inline__ |
| 142 | void ltt_write_event_header(const struct lib_ring_buffer_config *config, |
| 143 | struct lib_ring_buffer_ctx *ctx, |
| 144 | u16 eID, u32 event_size) |
| 145 | { |
| 146 | struct ltt_channel *ltt_chan = channel_get_private(ctx->chan); |
| 147 | |
| 148 | if (unlikely(ctx->rflags)) |
| 149 | goto slow_path; |
| 150 | |
| 151 | switch (ltt_chan->header_type) { |
| 152 | case 1: /* compact */ |
| 153 | { |
| 154 | uint32_t id_time = 0; |
| 155 | |
| 156 | bt_bitfield_write(&id_time, uint32_t, 0, 5, eID); |
| 157 | bt_bitfield_write(&id_time, uint32_t, 5, 27, ctx->tsc); |
| 158 | lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time)); |
| 159 | break; |
| 160 | } |
| 161 | case 2: /* large */ |
| 162 | { |
| 163 | uint16_t event_id = eID; |
| 164 | uint32_t timestamp = (uint32_t) ctx->tsc; |
| 165 | |
| 166 | lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id)); |
| 167 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint32_t)); |
| 168 | lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp)); |
| 169 | break; |
| 170 | } |
| 171 | default: |
| 172 | WARN_ON(1); |
| 173 | } |
| 174 | return; |
| 175 | |
| 176 | slow_path: |
| 177 | ltt_write_event_header_slow(config, ctx, eID, event_size); |
| 178 | } |
| 179 | |
| 180 | /* |
| 181 | * TODO: For now, we only support 65536 event ids per channel. |
| 182 | */ |
| 183 | void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config, |
| 184 | struct lib_ring_buffer_ctx *ctx, |
| 185 | u16 eID, u32 event_size) |
| 186 | { |
| 187 | struct ltt_channel *ltt_chan = channel_get_private(ctx->chan); |
| 188 | |
| 189 | switch (ltt_chan->header_type) { |
| 190 | case 1: /* compact */ |
| 191 | if (!(ctx->rflags & RING_BUFFER_RFLAG_FULL_TSC)) { |
| 192 | uint32_t id_time = 0; |
| 193 | |
| 194 | bt_bitfield_write(&id_time, uint32_t, 0, 5, eID); |
| 195 | bt_bitfield_write(&id_time, uint32_t, 5, 27, ctx->tsc); |
| 196 | lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time)); |
| 197 | } else { |
| 198 | uint8_t id = 0; |
| 199 | uint32_t event_id = (uint32_t) eID; |
| 200 | uint64_t timestamp = ctx->tsc; |
| 201 | |
| 202 | bt_bitfield_write(&id, uint8_t, 0, 5, 31); |
| 203 | lib_ring_buffer_write(config, ctx, &id, sizeof(id)); |
| 204 | /* Align extended struct on largest member */ |
| 205 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t)); |
| 206 | lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id)); |
| 207 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t)); |
| 208 | lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp)); |
| 209 | } |
| 210 | break; |
| 211 | case 2: /* large */ |
| 212 | { |
| 213 | if (!(ctx->rflags & RING_BUFFER_RFLAG_FULL_TSC)) { |
| 214 | uint16_t event_id = eID; |
| 215 | uint32_t timestamp = (uint32_t) ctx->tsc; |
| 216 | |
| 217 | lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id)); |
| 218 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint32_t)); |
| 219 | lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp)); |
| 220 | } else { |
| 221 | uint16_t event_id = 65535; |
| 222 | uint32_t event_id_ext = (uint32_t) eID; |
| 223 | uint64_t timestamp = ctx->tsc; |
| 224 | |
| 225 | lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id)); |
| 226 | /* Align extended struct on largest member */ |
| 227 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t)); |
| 228 | lib_ring_buffer_write(config, ctx, &event_id_ext, sizeof(event_id_ext)); |
| 229 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t)); |
| 230 | lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp)); |
| 231 | } |
| 232 | break; |
| 233 | } |
| 234 | default: |
| 235 | WARN_ON(1); |
| 236 | } |
| 237 | } |
| 238 | |
| 239 | static const struct lib_ring_buffer_config client_config; |
| 240 | |
| 241 | static u64 client_ring_buffer_clock_read(struct channel *chan) |
| 242 | { |
| 243 | return lib_ring_buffer_clock_read(chan); |
| 244 | } |
| 245 | |
| 246 | static |
| 247 | size_t client_record_header_size(const struct lib_ring_buffer_config *config, |
| 248 | struct channel *chan, size_t offset, |
| 249 | size_t data_size, |
| 250 | size_t *pre_header_padding, |
| 251 | unsigned int rflags, |
| 252 | struct lib_ring_buffer_ctx *ctx) |
| 253 | { |
| 254 | return record_header_size(config, chan, offset, data_size, |
| 255 | pre_header_padding, rflags, ctx); |
| 256 | } |
| 257 | |
| 258 | /** |
| 259 | * client_packet_header_size - called on buffer-switch to a new sub-buffer |
| 260 | * |
| 261 | * Return header size without padding after the structure. Don't use packed |
| 262 | * structure because gcc generates inefficient code on some architectures |
| 263 | * (powerpc, mips..) |
| 264 | */ |
| 265 | static size_t client_packet_header_size(void) |
| 266 | { |
| 267 | return offsetof(struct packet_header, ctx.header_end); |
| 268 | } |
| 269 | |
| 270 | static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc, |
| 271 | unsigned int subbuf_idx) |
| 272 | { |
| 273 | struct channel *chan = buf->backend.chan; |
| 274 | struct packet_header *header = |
| 275 | (struct packet_header *) |
| 276 | lib_ring_buffer_offset_address(&buf->backend, |
| 277 | subbuf_idx * chan->backend.subbuf_size); |
| 278 | struct ltt_channel *ltt_chan = channel_get_private(chan); |
| 279 | struct ltt_session *session = ltt_chan->session; |
| 280 | |
| 281 | header->magic = CTF_MAGIC_NUMBER; |
| 282 | memcpy(header->uuid, session->uuid.b, sizeof(session->uuid)); |
| 283 | header->stream_id = ltt_chan->id; |
| 284 | header->ctx.timestamp_begin = tsc; |
| 285 | header->ctx.timestamp_end = 0; |
| 286 | header->ctx.events_discarded = 0; |
| 287 | header->ctx.content_size = 0xFFFFFFFF; /* for debugging */ |
| 288 | header->ctx.packet_size = 0xFFFFFFFF; |
| 289 | header->ctx.cpu_id = buf->backend.cpu; |
| 290 | } |
| 291 | |
| 292 | /* |
| 293 | * offset is assumed to never be 0 here : never deliver a completely empty |
| 294 | * subbuffer. data_size is between 1 and subbuf_size. |
| 295 | */ |
| 296 | static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc, |
| 297 | unsigned int subbuf_idx, unsigned long data_size) |
| 298 | { |
| 299 | struct channel *chan = 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 | unsigned long records_lost = 0; |
| 305 | |
| 306 | header->ctx.timestamp_end = tsc; |
| 307 | header->ctx.content_size = data_size; |
| 308 | header->ctx.packet_size = PAGE_ALIGN(data_size); |
| 309 | records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf); |
| 310 | records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf); |
| 311 | records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf); |
| 312 | header->ctx.events_discarded = records_lost; |
| 313 | } |
| 314 | |
| 315 | static int client_buffer_create(struct lib_ring_buffer *buf, void *priv, |
| 316 | int cpu, const char *name) |
| 317 | { |
| 318 | return 0; |
| 319 | } |
| 320 | |
| 321 | static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu) |
| 322 | { |
| 323 | } |
| 324 | |
| 325 | static const struct lib_ring_buffer_config client_config = { |
| 326 | .cb.ring_buffer_clock_read = client_ring_buffer_clock_read, |
| 327 | .cb.record_header_size = client_record_header_size, |
| 328 | .cb.subbuffer_header_size = client_packet_header_size, |
| 329 | .cb.buffer_begin = client_buffer_begin, |
| 330 | .cb.buffer_end = client_buffer_end, |
| 331 | .cb.buffer_create = client_buffer_create, |
| 332 | .cb.buffer_finalize = client_buffer_finalize, |
| 333 | |
| 334 | .tsc_bits = 32, |
| 335 | .alloc = RING_BUFFER_ALLOC_PER_CPU, |
| 336 | .sync = RING_BUFFER_SYNC_PER_CPU, |
| 337 | .mode = RING_BUFFER_MODE_TEMPLATE, |
| 338 | .backend = RING_BUFFER_PAGE, |
| 339 | .output = RING_BUFFER_SPLICE, |
| 340 | .oops = RING_BUFFER_OOPS_CONSISTENCY, |
| 341 | .ipi = RING_BUFFER_IPI_BARRIER, |
| 342 | .wakeup = RING_BUFFER_WAKEUP_BY_TIMER, |
| 343 | }; |
| 344 | |
| 345 | static |
| 346 | struct channel *_channel_create(const char *name, |
| 347 | struct ltt_channel *ltt_chan, void *buf_addr, |
| 348 | size_t subbuf_size, size_t num_subbuf, |
| 349 | unsigned int switch_timer_interval, |
| 350 | unsigned int read_timer_interval) |
| 351 | { |
| 352 | return channel_create(&client_config, name, ltt_chan, buf_addr, |
| 353 | subbuf_size, num_subbuf, switch_timer_interval, |
| 354 | read_timer_interval); |
| 355 | } |
| 356 | |
| 357 | static |
| 358 | void ltt_channel_destroy(struct channel *chan) |
| 359 | { |
| 360 | channel_destroy(chan); |
| 361 | } |
| 362 | |
| 363 | static |
| 364 | struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan) |
| 365 | { |
| 366 | struct lib_ring_buffer *buf; |
| 367 | int cpu; |
| 368 | |
| 369 | for_each_channel_cpu(cpu, chan) { |
| 370 | buf = channel_get_ring_buffer(&client_config, chan, cpu); |
| 371 | if (!lib_ring_buffer_open_read(buf)) |
| 372 | return buf; |
| 373 | } |
| 374 | return NULL; |
| 375 | } |
| 376 | |
| 377 | static |
| 378 | void ltt_buffer_read_close(struct lib_ring_buffer *buf) |
| 379 | { |
| 380 | lib_ring_buffer_release_read(buf); |
| 381 | |
| 382 | } |
| 383 | |
| 384 | static |
| 385 | int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx) |
| 386 | { |
| 387 | int ret, cpu; |
| 388 | |
| 389 | cpu = lib_ring_buffer_get_cpu(&client_config); |
| 390 | if (cpu < 0) |
| 391 | return -EPERM; |
| 392 | ctx->cpu = cpu; |
| 393 | |
| 394 | ret = lib_ring_buffer_reserve(&client_config, ctx); |
| 395 | if (ret) |
| 396 | goto put; |
| 397 | return ret; |
| 398 | |
| 399 | put: |
| 400 | lib_ring_buffer_put_cpu(&client_config); |
| 401 | return ret; |
| 402 | } |
| 403 | |
| 404 | static |
| 405 | void ltt_event_commit(struct lib_ring_buffer_ctx *ctx) |
| 406 | { |
| 407 | lib_ring_buffer_commit(&client_config, ctx); |
| 408 | lib_ring_buffer_put_cpu(&client_config); |
| 409 | } |
| 410 | |
| 411 | static |
| 412 | void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src, |
| 413 | size_t len) |
| 414 | { |
| 415 | lib_ring_buffer_write(&client_config, ctx, src, len); |
| 416 | } |
| 417 | |
| 418 | static |
| 419 | wait_queue_head_t *ltt_get_reader_wait_queue(struct ltt_channel *chan) |
| 420 | { |
| 421 | return &chan->chan->read_wait; |
| 422 | } |
| 423 | |
| 424 | static struct ltt_transport ltt_relay_transport = { |
| 425 | .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING, |
| 426 | .owner = THIS_MODULE, |
| 427 | .ops = { |
| 428 | .channel_create = _channel_create, |
| 429 | .channel_destroy = ltt_channel_destroy, |
| 430 | .buffer_read_open = ltt_buffer_read_open, |
| 431 | .buffer_read_close = ltt_buffer_read_close, |
| 432 | .event_reserve = ltt_event_reserve, |
| 433 | .event_commit = ltt_event_commit, |
| 434 | .event_write = ltt_event_write, |
| 435 | .packet_avail_size = NULL, /* Would be racy anyway */ |
| 436 | .get_reader_wait_queue = ltt_get_reader_wait_queue, |
| 437 | }, |
| 438 | }; |
| 439 | |
| 440 | static int __init ltt_ring_buffer_client_init(void) |
| 441 | { |
| 442 | /* |
| 443 | * This vmalloc sync all also takes care of the lib ring buffer |
| 444 | * vmalloc'd module pages when it is built as a module into LTTng. |
| 445 | */ |
| 446 | wrapper_vmalloc_sync_all(); |
| 447 | printk(KERN_INFO "LTT : ltt ring buffer client init\n"); |
| 448 | ltt_transport_register(<t_relay_transport); |
| 449 | return 0; |
| 450 | } |
| 451 | |
| 452 | module_init(ltt_ring_buffer_client_init); |
| 453 | |
| 454 | static void __exit ltt_ring_buffer_client_exit(void) |
| 455 | { |
| 456 | printk(KERN_INFO "LTT : ltt ring buffer client exit\n"); |
| 457 | ltt_transport_unregister(<t_relay_transport); |
| 458 | } |
| 459 | |
| 460 | module_exit(ltt_ring_buffer_client_exit); |
| 461 | |
| 462 | MODULE_LICENSE("GPL and additional rights"); |
| 463 | MODULE_AUTHOR("Mathieu Desnoyers"); |
| 464 | MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING |
| 465 | " client"); |