2 * ltt-ring-buffer-client.h
4 * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6 * LTTng lib ring buffer client template.
8 * Dual LGPL v2.1/GPL v2 license.
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"
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.
25 struct packet_header
{
26 /* Trace packet header */
29 * contains endianness information.
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.
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 */
51 static inline notrace u64
lib_ring_buffer_clock_read(struct channel
*chan
)
53 return trace_clock_read64();
57 size_t ctx_get_size(size_t offset
, struct lttng_ctx
*ctx
)
60 size_t orig_offset
= offset
;
64 for (i
= 0; i
< ctx
->nr_fields
; i
++)
65 offset
+= ctx
->fields
[i
].get_size(offset
);
66 return offset
- orig_offset
;
70 void ctx_record(struct lib_ring_buffer_ctx
*bufctx
,
71 struct ltt_channel
*chan
,
72 struct lttng_ctx
*ctx
)
78 for (i
= 0; i
< ctx
->nr_fields
; i
++)
79 ctx
->fields
[i
].record(&ctx
->fields
[i
], bufctx
, chan
);
83 * record_header_size - Calculate the header size and padding necessary.
84 * @config: ring buffer instance configuration
86 * @offset: offset in the write buffer
87 * @pre_header_padding: padding to add before the header (output)
88 * @ctx: reservation context
90 * Returns the event header size (including padding).
92 * The payload must itself determine its own alignment from the biggest type it
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
)
101 struct ltt_channel
*ltt_chan
= channel_get_private(chan
);
102 struct ltt_event
*event
= ctx
->priv
;
103 size_t orig_offset
= offset
;
106 switch (ltt_chan
->header_type
) {
107 case 1: /* compact */
108 padding
= lib_ring_buffer_align(offset
, lttng_alignof(uint32_t));
110 if (!(ctx
->rflags
& (RING_BUFFER_RFLAG_FULL_TSC
| LTT_RFLAG_EXTENDED
))) {
111 offset
+= sizeof(uint32_t); /* id and timestamp */
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 */
123 padding
= lib_ring_buffer_align(offset
, lttng_alignof(uint16_t));
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 */
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 */
141 offset
+= ctx_get_size(offset
, event
->ctx
);
142 offset
+= ctx_get_size(offset
, ltt_chan
->ctx
);
144 *pre_header_padding
= padding
;
145 return offset
- orig_offset
;
148 #include "../libringbuffer/api.h"
151 void ltt_write_event_header_slow(const struct lib_ring_buffer_config
*config
,
152 struct lib_ring_buffer_ctx
*ctx
,
156 * ltt_write_event_header
158 * Writes the event header to the offset (already aligned on 32-bits).
160 * @config: ring buffer instance configuration
161 * @ctx: reservation context
162 * @event_id: event ID
165 void ltt_write_event_header(const struct lib_ring_buffer_config
*config
,
166 struct lib_ring_buffer_ctx
*ctx
,
169 struct ltt_channel
*ltt_chan
= channel_get_private(ctx
->chan
);
170 struct ltt_event
*event
= ctx
->priv
;
172 if (unlikely(ctx
->rflags
))
175 switch (ltt_chan
->header_type
) {
176 case 1: /* compact */
178 uint32_t id_time
= 0;
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
));
187 uint32_t timestamp
= (uint32_t) ctx
->tsc
;
188 uint16_t id
= event_id
;
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
, ×tamp
, sizeof(timestamp
));
199 ctx_record(ctx
, ltt_chan
, ltt_chan
->ctx
);
200 ctx_record(ctx
, ltt_chan
, event
->ctx
);
205 ltt_write_event_header_slow(config
, ctx
, event_id
);
209 void ltt_write_event_header_slow(const struct lib_ring_buffer_config
*config
,
210 struct lib_ring_buffer_ctx
*ctx
,
213 struct ltt_channel
*ltt_chan
= channel_get_private(ctx
->chan
);
214 struct ltt_event
*event
= ctx
->priv
;
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;
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
));
226 uint64_t timestamp
= ctx
->tsc
;
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
, ×tamp
, sizeof(timestamp
));
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
;
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
, ×tamp
, sizeof(timestamp
));
248 uint64_t timestamp
= ctx
->tsc
;
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
, ×tamp
, sizeof(timestamp
));
262 ctx_record(ctx
, ltt_chan
, ltt_chan
->ctx
);
263 ctx_record(ctx
, ltt_chan
, event
->ctx
);
266 static const struct lib_ring_buffer_config client_config
;
268 static u64
client_ring_buffer_clock_read(struct channel
*chan
)
270 return lib_ring_buffer_clock_read(chan
);
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
)
279 return record_header_size(config
, chan
, offset
,
280 pre_header_padding
, ctx
);
284 * client_packet_header_size - called on buffer-switch to a new sub-buffer
286 * Return header size without padding after the structure. Don't use packed
287 * structure because gcc generates inefficient code on some architectures
290 static size_t client_packet_header_size(void)
292 return offsetof(struct packet_header
, ctx
.header_end
);
295 static void client_buffer_begin(struct lib_ring_buffer
*buf
, u64 tsc
,
296 unsigned int subbuf_idx
,
297 struct shm_handle
*handle
)
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
,
305 struct ltt_channel
*ltt_chan
= channel_get_private(chan
);
306 struct ltt_session
*session
= ltt_chan
->session
;
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
;
320 * offset is assumed to never be 0 here : never deliver a completely empty
321 * subbuffer. data_size is between 1 and subbuf_size.
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
)
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
,
333 unsigned long records_lost
= 0;
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 */
339 * We do not care about the records lost count, because the metadata
340 * channel waits and retry.
342 (void) lib_ring_buffer_get_records_lost_full(&client_config
, buf
);
343 records_lost
+= lib_ring_buffer_get_records_lost_wrap(&client_config
, buf
);
344 records_lost
+= lib_ring_buffer_get_records_lost_big(&client_config
, buf
);
345 header
->ctx
.events_discarded
= records_lost
;
348 static int client_buffer_create(struct lib_ring_buffer
*buf
, void *priv
,
349 int cpu
, const char *name
, struct shm_handle
*handle
)
354 static void client_buffer_finalize(struct lib_ring_buffer
*buf
, void *priv
, int cpu
, struct shm_handle
*handle
)
358 static const struct lib_ring_buffer_config client_config
= {
359 .cb
.ring_buffer_clock_read
= client_ring_buffer_clock_read
,
360 .cb
.record_header_size
= client_record_header_size
,
361 .cb
.subbuffer_header_size
= client_packet_header_size
,
362 .cb
.buffer_begin
= client_buffer_begin
,
363 .cb
.buffer_end
= client_buffer_end
,
364 .cb
.buffer_create
= client_buffer_create
,
365 .cb
.buffer_finalize
= client_buffer_finalize
,
368 .alloc
= RING_BUFFER_ALLOC_PER_CPU
,
369 .sync
= RING_BUFFER_SYNC_GLOBAL
,
370 .mode
= RING_BUFFER_MODE_TEMPLATE
,
371 .backend
= RING_BUFFER_PAGE
,
372 .output
= RING_BUFFER_MMAP
,
373 .oops
= RING_BUFFER_OOPS_CONSISTENCY
,
374 .ipi
= RING_BUFFER_NO_IPI_BARRIER
,
375 .wakeup
= RING_BUFFER_WAKEUP_BY_WRITER
,
379 struct ltt_channel
*_channel_create(const char *name
,
380 struct ltt_channel
*ltt_chan
, void *buf_addr
,
381 size_t subbuf_size
, size_t num_subbuf
,
382 unsigned int switch_timer_interval
,
383 unsigned int read_timer_interval
,
384 int *shm_fd
, int *wait_fd
,
385 uint64_t *memory_map_size
)
387 ltt_chan
->handle
= channel_create(&client_config
, name
, ltt_chan
, buf_addr
,
388 subbuf_size
, num_subbuf
, switch_timer_interval
,
389 read_timer_interval
, shm_fd
, wait_fd
,
391 if (!ltt_chan
->handle
)
393 ltt_chan
->chan
= shmp(ltt_chan
->handle
, ltt_chan
->handle
->chan
);
398 void ltt_channel_destroy(struct ltt_channel
*ltt_chan
)
400 channel_destroy(ltt_chan
->chan
, ltt_chan
->handle
);
404 struct lib_ring_buffer
*ltt_buffer_read_open(struct channel
*chan
,
405 struct shm_handle
*handle
,
406 int *shm_fd
, int *wait_fd
,
407 uint64_t *memory_map_size
)
409 struct lib_ring_buffer
*buf
;
412 for_each_channel_cpu(cpu
, chan
) {
413 buf
= channel_get_ring_buffer(&client_config
, chan
,
414 cpu
, handle
, shm_fd
, wait_fd
,
416 if (!lib_ring_buffer_open_read(buf
, handle
))
423 void ltt_buffer_read_close(struct lib_ring_buffer
*buf
,
424 struct shm_handle
*handle
)
426 lib_ring_buffer_release_read(buf
, handle
);
430 int ltt_event_reserve(struct lib_ring_buffer_ctx
*ctx
,
433 struct ltt_channel
*ltt_chan
= channel_get_private(ctx
->chan
);
436 cpu
= lib_ring_buffer_get_cpu(&client_config
);
441 switch (ltt_chan
->header_type
) {
442 case 1: /* compact */
444 ctx
->rflags
|= LTT_RFLAG_EXTENDED
;
447 if (event_id
> 65534)
448 ctx
->rflags
|= LTT_RFLAG_EXTENDED
;
454 ret
= lib_ring_buffer_reserve(&client_config
, ctx
);
457 ltt_write_event_header(&client_config
, ctx
, event_id
);
460 lib_ring_buffer_put_cpu(&client_config
);
465 void ltt_event_commit(struct lib_ring_buffer_ctx
*ctx
)
467 lib_ring_buffer_commit(&client_config
, ctx
);
468 lib_ring_buffer_put_cpu(&client_config
);
472 void ltt_event_write(struct lib_ring_buffer_ctx
*ctx
, const void *src
,
475 lib_ring_buffer_write(&client_config
, ctx
, src
, len
);
480 wait_queue_head_t
*ltt_get_reader_wait_queue(struct channel
*chan
)
482 return &chan
->read_wait
;
486 wait_queue_head_t
*ltt_get_hp_wait_queue(struct channel
*chan
)
488 return &chan
->hp_wait
;
493 int ltt_is_finalized(struct channel
*chan
)
495 return lib_ring_buffer_channel_is_finalized(chan
);
499 int ltt_is_disabled(struct channel
*chan
)
501 return lib_ring_buffer_channel_is_disabled(chan
);
504 static struct ltt_transport ltt_relay_transport
= {
505 .name
= "relay-" RING_BUFFER_MODE_TEMPLATE_STRING
"-mmap",
507 .channel_create
= _channel_create
,
508 .channel_destroy
= ltt_channel_destroy
,
509 .buffer_read_open
= ltt_buffer_read_open
,
510 .buffer_read_close
= ltt_buffer_read_close
,
511 .event_reserve
= ltt_event_reserve
,
512 .event_commit
= ltt_event_commit
,
513 .event_write
= ltt_event_write
,
514 .packet_avail_size
= NULL
, /* Would be racy anyway */
515 //.get_reader_wait_queue = ltt_get_reader_wait_queue,
516 //.get_hp_wait_queue = ltt_get_hp_wait_queue,
517 .is_finalized
= ltt_is_finalized
,
518 .is_disabled
= ltt_is_disabled
,
522 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
524 DBG("LTT : ltt ring buffer client init\n");
525 ltt_transport_register(<t_relay_transport
);
528 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
530 DBG("LTT : ltt ring buffer client exit\n");
531 ltt_transport_unregister(<t_relay_transport
);