2 * lttng-ring-buffer-client.h
4 * LTTng lib ring buffer client template.
6 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; only
11 * version 2.1 of the License.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include <lttng/ust-events.h>
25 #include "lttng/bitfield.h"
27 #include "lttng-tracer.h"
28 #include "../libringbuffer/frontend_types.h"
30 #define LTTNG_COMPACT_EVENT_BITS 5
31 #define LTTNG_COMPACT_TSC_BITS 27
34 * Keep the natural field alignment for _each field_ within this structure if
35 * you ever add/remove a field from this header. Packed attribute is not used
36 * because gcc generates poor code on at least powerpc and mips. Don't ever
37 * let gcc add padding between the structure elements.
40 struct packet_header
{
41 /* Trace packet header */
44 * contains endianness information.
46 uint8_t uuid
[LTTNG_UST_UUID_LEN
];
50 /* Stream packet context */
51 uint64_t timestamp_begin
; /* Cycle count at subbuffer start */
52 uint64_t timestamp_end
; /* Cycle count at subbuffer end */
53 uint64_t content_size
; /* Size of data in subbuffer */
54 uint64_t packet_size
; /* Subbuffer size (include padding) */
55 unsigned long events_discarded
; /*
56 * Events lost in this subbuffer since
57 * the beginning of the trace.
60 uint32_t cpu_id
; /* CPU id associated with stream */
61 uint8_t header_end
; /* End of header */
66 static inline uint64_t lib_ring_buffer_clock_read(struct channel
*chan
)
68 return trace_clock_read64();
72 size_t ctx_get_size(size_t offset
, struct lttng_ctx
*ctx
)
75 size_t orig_offset
= offset
;
79 for (i
= 0; i
< ctx
->nr_fields
; i
++)
80 offset
+= ctx
->fields
[i
].get_size(offset
);
81 return offset
- orig_offset
;
85 void ctx_record(struct lttng_ust_lib_ring_buffer_ctx
*bufctx
,
86 struct lttng_channel
*chan
,
87 struct lttng_ctx
*ctx
)
93 for (i
= 0; i
< ctx
->nr_fields
; i
++)
94 ctx
->fields
[i
].record(&ctx
->fields
[i
], bufctx
, chan
);
98 * record_header_size - Calculate the header size and padding necessary.
99 * @config: ring buffer instance configuration
101 * @offset: offset in the write buffer
102 * @pre_header_padding: padding to add before the header (output)
103 * @ctx: reservation context
105 * Returns the event header size (including padding).
107 * The payload must itself determine its own alignment from the biggest type it
111 unsigned char record_header_size(const struct lttng_ust_lib_ring_buffer_config
*config
,
112 struct channel
*chan
, size_t offset
,
113 size_t *pre_header_padding
,
114 struct lttng_ust_lib_ring_buffer_ctx
*ctx
)
116 struct lttng_channel
*lttng_chan
= channel_get_private(chan
);
117 struct lttng_event
*event
= ctx
->priv
;
118 size_t orig_offset
= offset
;
121 switch (lttng_chan
->header_type
) {
122 case 1: /* compact */
123 padding
= lib_ring_buffer_align(offset
, lttng_alignof(uint32_t));
125 if (!(ctx
->rflags
& (RING_BUFFER_RFLAG_FULL_TSC
| LTTNG_RFLAG_EXTENDED
))) {
126 offset
+= sizeof(uint32_t); /* id and timestamp */
128 /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
129 offset
+= (LTTNG_COMPACT_EVENT_BITS
+ CHAR_BIT
- 1) / CHAR_BIT
;
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 */
138 padding
= lib_ring_buffer_align(offset
, lttng_alignof(uint16_t));
140 offset
+= sizeof(uint16_t);
141 if (!(ctx
->rflags
& (RING_BUFFER_RFLAG_FULL_TSC
| LTTNG_RFLAG_EXTENDED
))) {
142 offset
+= lib_ring_buffer_align(offset
, lttng_alignof(uint32_t));
143 offset
+= sizeof(uint32_t); /* timestamp */
145 /* Align extended struct on largest member */
146 offset
+= lib_ring_buffer_align(offset
, lttng_alignof(uint64_t));
147 offset
+= sizeof(uint32_t); /* id */
148 offset
+= lib_ring_buffer_align(offset
, lttng_alignof(uint64_t));
149 offset
+= sizeof(uint64_t); /* timestamp */
156 offset
+= ctx_get_size(offset
, event
->ctx
);
157 offset
+= ctx_get_size(offset
, lttng_chan
->ctx
);
159 *pre_header_padding
= padding
;
160 return offset
- orig_offset
;
163 #include "../libringbuffer/api.h"
164 #include "lttng-rb-clients.h"
167 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config
*config
,
168 struct lttng_ust_lib_ring_buffer_ctx
*ctx
,
172 * lttng_write_event_header
174 * Writes the event header to the offset (already aligned on 32-bits).
176 * @config: ring buffer instance configuration
177 * @ctx: reservation context
178 * @event_id: event ID
181 void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config
*config
,
182 struct lttng_ust_lib_ring_buffer_ctx
*ctx
,
185 struct lttng_channel
*lttng_chan
= channel_get_private(ctx
->chan
);
186 struct lttng_event
*event
= ctx
->priv
;
188 if (caa_unlikely(ctx
->rflags
))
191 switch (lttng_chan
->header_type
) {
192 case 1: /* compact */
194 uint32_t id_time
= 0;
196 bt_bitfield_write(&id_time
, uint32_t,
198 LTTNG_COMPACT_EVENT_BITS
,
200 bt_bitfield_write(&id_time
, uint32_t,
201 LTTNG_COMPACT_EVENT_BITS
,
202 LTTNG_COMPACT_TSC_BITS
,
204 lib_ring_buffer_write(config
, ctx
, &id_time
, sizeof(id_time
));
209 uint32_t timestamp
= (uint32_t) ctx
->tsc
;
210 uint16_t id
= event_id
;
212 lib_ring_buffer_write(config
, ctx
, &id
, sizeof(id
));
213 lib_ring_buffer_align_ctx(ctx
, lttng_alignof(uint32_t));
214 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
221 ctx_record(ctx
, lttng_chan
, lttng_chan
->ctx
);
222 ctx_record(ctx
, lttng_chan
, event
->ctx
);
223 lib_ring_buffer_align_ctx(ctx
, ctx
->largest_align
);
228 lttng_write_event_header_slow(config
, ctx
, event_id
);
232 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config
*config
,
233 struct lttng_ust_lib_ring_buffer_ctx
*ctx
,
236 struct lttng_channel
*lttng_chan
= channel_get_private(ctx
->chan
);
237 struct lttng_event
*event
= ctx
->priv
;
239 switch (lttng_chan
->header_type
) {
240 case 1: /* compact */
241 if (!(ctx
->rflags
& (RING_BUFFER_RFLAG_FULL_TSC
| LTTNG_RFLAG_EXTENDED
))) {
242 uint32_t id_time
= 0;
244 bt_bitfield_write(&id_time
, uint32_t,
246 LTTNG_COMPACT_EVENT_BITS
,
248 bt_bitfield_write(&id_time
, uint32_t,
249 LTTNG_COMPACT_EVENT_BITS
,
250 LTTNG_COMPACT_TSC_BITS
,
252 lib_ring_buffer_write(config
, ctx
, &id_time
, sizeof(id_time
));
255 uint64_t timestamp
= ctx
->tsc
;
257 bt_bitfield_write(&id
, uint8_t,
259 LTTNG_COMPACT_EVENT_BITS
,
261 lib_ring_buffer_write(config
, ctx
, &id
, sizeof(id
));
262 /* Align extended struct on largest member */
263 lib_ring_buffer_align_ctx(ctx
, lttng_alignof(uint64_t));
264 lib_ring_buffer_write(config
, ctx
, &event_id
, sizeof(event_id
));
265 lib_ring_buffer_align_ctx(ctx
, lttng_alignof(uint64_t));
266 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
271 if (!(ctx
->rflags
& (RING_BUFFER_RFLAG_FULL_TSC
| LTTNG_RFLAG_EXTENDED
))) {
272 uint32_t timestamp
= (uint32_t) ctx
->tsc
;
273 uint16_t id
= event_id
;
275 lib_ring_buffer_write(config
, ctx
, &id
, sizeof(id
));
276 lib_ring_buffer_align_ctx(ctx
, lttng_alignof(uint32_t));
277 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
280 uint64_t timestamp
= ctx
->tsc
;
282 lib_ring_buffer_write(config
, ctx
, &id
, sizeof(id
));
283 /* Align extended struct on largest member */
284 lib_ring_buffer_align_ctx(ctx
, lttng_alignof(uint64_t));
285 lib_ring_buffer_write(config
, ctx
, &event_id
, sizeof(event_id
));
286 lib_ring_buffer_align_ctx(ctx
, lttng_alignof(uint64_t));
287 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
294 ctx_record(ctx
, lttng_chan
, lttng_chan
->ctx
);
295 ctx_record(ctx
, lttng_chan
, event
->ctx
);
296 lib_ring_buffer_align_ctx(ctx
, ctx
->largest_align
);
299 static const struct lttng_ust_lib_ring_buffer_config client_config
;
301 static uint64_t client_ring_buffer_clock_read(struct channel
*chan
)
303 return lib_ring_buffer_clock_read(chan
);
307 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config
*config
,
308 struct channel
*chan
, size_t offset
,
309 size_t *pre_header_padding
,
310 struct lttng_ust_lib_ring_buffer_ctx
*ctx
)
312 return record_header_size(config
, chan
, offset
,
313 pre_header_padding
, ctx
);
317 * client_packet_header_size - called on buffer-switch to a new sub-buffer
319 * Return header size without padding after the structure. Don't use packed
320 * structure because gcc generates inefficient code on some architectures
323 static size_t client_packet_header_size(void)
325 return offsetof(struct packet_header
, ctx
.header_end
);
328 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer
*buf
, uint64_t tsc
,
329 unsigned int subbuf_idx
,
330 struct lttng_ust_shm_handle
*handle
)
332 struct channel
*chan
= shmp(handle
, buf
->backend
.chan
);
333 struct packet_header
*header
=
334 (struct packet_header
*)
335 lib_ring_buffer_offset_address(&buf
->backend
,
336 subbuf_idx
* chan
->backend
.subbuf_size
,
338 struct lttng_channel
*lttng_chan
= channel_get_private(chan
);
340 header
->magic
= CTF_MAGIC_NUMBER
;
341 memcpy(header
->uuid
, lttng_chan
->uuid
, sizeof(lttng_chan
->uuid
));
342 header
->stream_id
= lttng_chan
->id
;
343 header
->ctx
.timestamp_begin
= tsc
;
344 header
->ctx
.timestamp_end
= 0;
345 header
->ctx
.content_size
= ~0ULL; /* for debugging */
346 header
->ctx
.packet_size
= ~0ULL;
347 header
->ctx
.events_discarded
= 0;
348 header
->ctx
.cpu_id
= buf
->backend
.cpu
;
352 * offset is assumed to never be 0 here : never deliver a completely empty
353 * subbuffer. data_size is between 1 and subbuf_size.
355 static void client_buffer_end(struct lttng_ust_lib_ring_buffer
*buf
, uint64_t tsc
,
356 unsigned int subbuf_idx
, unsigned long data_size
,
357 struct lttng_ust_shm_handle
*handle
)
359 struct channel
*chan
= shmp(handle
, buf
->backend
.chan
);
360 struct packet_header
*header
=
361 (struct packet_header
*)
362 lib_ring_buffer_offset_address(&buf
->backend
,
363 subbuf_idx
* chan
->backend
.subbuf_size
,
365 unsigned long records_lost
= 0;
367 header
->ctx
.timestamp_end
= tsc
;
368 header
->ctx
.content_size
=
369 (uint64_t) data_size
* CHAR_BIT
; /* in bits */
370 header
->ctx
.packet_size
=
371 (uint64_t) PAGE_ALIGN(data_size
) * CHAR_BIT
; /* in bits */
373 records_lost
+= lib_ring_buffer_get_records_lost_full(&client_config
, buf
);
374 records_lost
+= lib_ring_buffer_get_records_lost_wrap(&client_config
, buf
);
375 records_lost
+= lib_ring_buffer_get_records_lost_big(&client_config
, buf
);
376 header
->ctx
.events_discarded
= records_lost
;
379 static int client_buffer_create(struct lttng_ust_lib_ring_buffer
*buf
, void *priv
,
380 int cpu
, const char *name
, struct lttng_ust_shm_handle
*handle
)
385 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer
*buf
, void *priv
, int cpu
, struct lttng_ust_shm_handle
*handle
)
389 static struct packet_header
*client_packet_header(struct lttng_ust_lib_ring_buffer
*buf
,
390 struct lttng_ust_shm_handle
*handle
)
392 struct channel
*chan
= shmp(handle
, buf
->backend
.chan
);
393 struct lttng_channel
*lttng_chan
= channel_get_private(chan
);
394 unsigned long sb_index
;
395 struct lttng_ust_lib_ring_buffer_backend
*bufb
;
396 struct packet_header
*header
;
398 bufb
= &buf
->backend
;
399 sb_index
= subbuffer_id_get_index(<tng_chan
->chan
->backend
.config
,
401 header
= lib_ring_buffer_offset_address(bufb
,
402 sb_index
* lttng_chan
->chan
->backend
.subbuf_size
,
407 static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer
*buf
,
408 struct lttng_ust_shm_handle
*handle
,
409 uint64_t *timestamp_begin
)
411 struct packet_header
*header
;
413 header
= client_packet_header(buf
, handle
);
414 *timestamp_begin
= header
->ctx
.timestamp_begin
;
418 static int client_timestamp_end(struct lttng_ust_lib_ring_buffer
*buf
,
419 struct lttng_ust_shm_handle
*handle
,
420 uint64_t *timestamp_end
)
422 struct packet_header
*header
;
424 header
= client_packet_header(buf
, handle
);
425 *timestamp_end
= header
->ctx
.timestamp_end
;
429 static int client_events_discarded(struct lttng_ust_lib_ring_buffer
*buf
,
430 struct lttng_ust_shm_handle
*handle
,
431 uint64_t *events_discarded
)
433 struct packet_header
*header
;
435 header
= client_packet_header(buf
, handle
);
436 *events_discarded
= header
->ctx
.events_discarded
;
440 static int client_content_size(struct lttng_ust_lib_ring_buffer
*buf
,
441 struct lttng_ust_shm_handle
*handle
,
442 uint64_t *content_size
)
444 struct packet_header
*header
;
446 header
= client_packet_header(buf
, handle
);
447 *content_size
= header
->ctx
.content_size
;
451 static int client_packet_size(struct lttng_ust_lib_ring_buffer
*buf
,
452 struct lttng_ust_shm_handle
*handle
,
453 uint64_t *packet_size
)
455 struct packet_header
*header
;
457 header
= client_packet_header(buf
, handle
);
458 *packet_size
= header
->ctx
.packet_size
;
462 static int client_stream_id(struct lttng_ust_lib_ring_buffer
*buf
,
463 struct lttng_ust_shm_handle
*handle
,
466 struct packet_header
*header
;
468 header
= client_packet_header(buf
, handle
);
469 *stream_id
= header
->stream_id
;
473 static int client_current_timestamp(struct lttng_ust_lib_ring_buffer
*buf
,
474 struct lttng_ust_shm_handle
*handle
,
477 struct channel
*chan
;
479 chan
= shmp(handle
, handle
->chan
);
480 *ts
= client_ring_buffer_clock_read(chan
);
486 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb
= {
488 .ring_buffer_clock_read
= client_ring_buffer_clock_read
,
489 .record_header_size
= client_record_header_size
,
490 .subbuffer_header_size
= client_packet_header_size
,
491 .buffer_begin
= client_buffer_begin
,
492 .buffer_end
= client_buffer_end
,
493 .buffer_create
= client_buffer_create
,
494 .buffer_finalize
= client_buffer_finalize
,
496 .timestamp_begin
= client_timestamp_begin
,
497 .timestamp_end
= client_timestamp_end
,
498 .events_discarded
= client_events_discarded
,
499 .content_size
= client_content_size
,
500 .packet_size
= client_packet_size
,
501 .stream_id
= client_stream_id
,
502 .current_timestamp
= client_current_timestamp
,
505 static const struct lttng_ust_lib_ring_buffer_config client_config
= {
506 .cb
.ring_buffer_clock_read
= client_ring_buffer_clock_read
,
507 .cb
.record_header_size
= client_record_header_size
,
508 .cb
.subbuffer_header_size
= client_packet_header_size
,
509 .cb
.buffer_begin
= client_buffer_begin
,
510 .cb
.buffer_end
= client_buffer_end
,
511 .cb
.buffer_create
= client_buffer_create
,
512 .cb
.buffer_finalize
= client_buffer_finalize
,
514 .tsc_bits
= LTTNG_COMPACT_TSC_BITS
,
515 .alloc
= RING_BUFFER_ALLOC_PER_CPU
,
516 .sync
= RING_BUFFER_SYNC_GLOBAL
,
517 .mode
= RING_BUFFER_MODE_TEMPLATE
,
518 .backend
= RING_BUFFER_PAGE
,
519 .output
= RING_BUFFER_MMAP
,
520 .oops
= RING_BUFFER_OOPS_CONSISTENCY
,
521 .ipi
= RING_BUFFER_NO_IPI_BARRIER
,
522 .wakeup
= LTTNG_CLIENT_WAKEUP
,
523 .client_type
= LTTNG_CLIENT_TYPE
,
525 .cb_ptr
= &client_cb
.parent
,
528 const struct lttng_ust_client_lib_ring_buffer_client_cb
*LTTNG_CLIENT_CALLBACKS
= &client_cb
;
531 struct lttng_channel
*_channel_create(const char *name
,
533 size_t subbuf_size
, size_t num_subbuf
,
534 unsigned int switch_timer_interval
,
535 unsigned int read_timer_interval
,
539 struct lttng_channel chan_priv_init
;
540 struct lttng_ust_shm_handle
*handle
;
541 struct lttng_channel
*lttng_chan
;
544 memset(&chan_priv_init
, 0, sizeof(chan_priv_init
));
545 memcpy(chan_priv_init
.uuid
, uuid
, LTTNG_UST_UUID_LEN
);
546 chan_priv_init
.id
= chan_id
;
547 handle
= channel_create(&client_config
, name
,
548 &priv
, __alignof__(struct lttng_channel
),
549 sizeof(struct lttng_channel
),
551 buf_addr
, subbuf_size
, num_subbuf
,
552 switch_timer_interval
, read_timer_interval
);
556 lttng_chan
->handle
= handle
;
557 lttng_chan
->chan
= shmp(handle
, handle
->chan
);
562 void lttng_channel_destroy(struct lttng_channel
*chan
)
564 channel_destroy(chan
->chan
, chan
->handle
, 1);
568 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx
*ctx
,
571 struct lttng_channel
*lttng_chan
= channel_get_private(ctx
->chan
);
574 cpu
= lib_ring_buffer_get_cpu(&client_config
);
579 switch (lttng_chan
->header_type
) {
580 case 1: /* compact */
582 ctx
->rflags
|= LTTNG_RFLAG_EXTENDED
;
585 if (event_id
> 65534)
586 ctx
->rflags
|= LTTNG_RFLAG_EXTENDED
;
592 ret
= lib_ring_buffer_reserve(&client_config
, ctx
);
595 lttng_write_event_header(&client_config
, ctx
, event_id
);
598 lib_ring_buffer_put_cpu(&client_config
);
603 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx
*ctx
)
605 lib_ring_buffer_commit(&client_config
, ctx
);
606 lib_ring_buffer_put_cpu(&client_config
);
610 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx
*ctx
, const void *src
,
613 lib_ring_buffer_write(&client_config
, ctx
, src
, len
);
618 wait_queue_head_t
*lttng_get_reader_wait_queue(struct channel
*chan
)
620 return &chan
->read_wait
;
624 wait_queue_head_t
*lttng_get_hp_wait_queue(struct channel
*chan
)
626 return &chan
->hp_wait
;
631 int lttng_is_finalized(struct channel
*chan
)
633 return lib_ring_buffer_channel_is_finalized(chan
);
637 int lttng_is_disabled(struct channel
*chan
)
639 return lib_ring_buffer_channel_is_disabled(chan
);
643 int lttng_flush_buffer(struct channel
*chan
, struct lttng_ust_shm_handle
*handle
)
645 struct lttng_ust_lib_ring_buffer
*buf
;
648 for_each_channel_cpu(cpu
, chan
) {
649 int shm_fd
, wait_fd
, wakeup_fd
;
650 uint64_t memory_map_size
;
652 buf
= channel_get_ring_buffer(&client_config
, chan
,
653 cpu
, handle
, &shm_fd
, &wait_fd
,
654 &wakeup_fd
, &memory_map_size
);
655 lib_ring_buffer_switch(&client_config
, buf
,
656 SWITCH_ACTIVE
, handle
);
661 static struct lttng_transport lttng_relay_transport
= {
662 .name
= "relay-" RING_BUFFER_MODE_TEMPLATE_STRING
"-mmap",
664 .channel_create
= _channel_create
,
665 .channel_destroy
= lttng_channel_destroy
,
666 .event_reserve
= lttng_event_reserve
,
667 .event_commit
= lttng_event_commit
,
668 .event_write
= lttng_event_write
,
669 .packet_avail_size
= NULL
, /* Would be racy anyway */
670 //.get_reader_wait_queue = lttng_get_reader_wait_queue,
671 //.get_hp_wait_queue = lttng_get_hp_wait_queue,
672 .is_finalized
= lttng_is_finalized
,
673 .is_disabled
= lttng_is_disabled
,
674 .flush_buffer
= lttng_flush_buffer
,
676 .client_config
= &client_config
,
679 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
681 DBG("LTT : ltt ring buffer client \"%s\" init\n",
682 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING
"-mmap");
683 lttng_transport_register(<tng_relay_transport
);
686 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
688 DBG("LTT : ltt ring buffer client \"%s\" exit\n",
689 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING
"-mmap");
690 lttng_transport_unregister(<tng_relay_transport
);