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.
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"
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.
27 struct packet_header
{
28 /* Trace packet header */
31 * contains endianness information.
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.
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 */
53 static inline notrace u64
lib_ring_buffer_clock_read(struct channel
*chan
)
55 return trace_clock_read64();
59 * record_header_size - Calculate the header size and padding necessary.
60 * @config: ring buffer instance configuration
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
68 * Returns the event header size (including padding).
70 * The payload must itself determine its own alignment from the biggest type it
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
,
78 struct lib_ring_buffer_ctx
*ctx
)
80 struct ltt_channel
*ltt_chan
= channel_get_private(chan
);
81 size_t orig_offset
= offset
;
84 switch (ltt_chan
->header_type
) {
86 padding
= lib_ring_buffer_align(offset
, ltt_alignof(uint32_t));
88 if (!(rflags
& RING_BUFFER_RFLAG_FULL_TSC
)) {
89 offset
+= sizeof(uint32_t); /* id and timestamp */
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 */
101 padding
= lib_ring_buffer_align(offset
, ltt_alignof(uint16_t));
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 */
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 */
120 *pre_header_padding
= padding
;
121 return offset
- orig_offset
;
124 #include "wrapper/ringbuffer/api.h"
127 void ltt_write_event_header_slow(const struct lib_ring_buffer_config
*config
,
128 struct lib_ring_buffer_ctx
*ctx
,
132 * ltt_write_event_header
134 * Writes the event header to the offset (already aligned on 32-bits).
136 * @config: ring buffer instance configuration
137 * @ctx: reservation context
138 * @event_id: event ID
141 void ltt_write_event_header(const struct lib_ring_buffer_config
*config
,
142 struct lib_ring_buffer_ctx
*ctx
,
145 struct ltt_channel
*ltt_chan
= channel_get_private(ctx
->chan
);
147 if (unlikely(ctx
->rflags
))
150 switch (ltt_chan
->header_type
) {
151 case 1: /* compact */
153 uint32_t id_time
= 0;
155 bt_bitfield_write(&id_time
, uint32_t, 0, 5, event_id
);
156 bt_bitfield_write(&id_time
, uint32_t, 5, 27, ctx
->tsc
);
157 lib_ring_buffer_write(config
, ctx
, &id_time
, sizeof(id_time
));
162 uint32_t timestamp
= (uint32_t) ctx
->tsc
;
164 lib_ring_buffer_write(config
, ctx
, &event_id
, sizeof(event_id
));
165 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint32_t));
166 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
175 ltt_write_event_header_slow(config
, ctx
, event_id
);
179 * TODO: For now, we only support 65536 event ids per channel.
181 void ltt_write_event_header_slow(const struct lib_ring_buffer_config
*config
,
182 struct lib_ring_buffer_ctx
*ctx
,
185 struct ltt_channel
*ltt_chan
= channel_get_private(ctx
->chan
);
187 switch (ltt_chan
->header_type
) {
188 case 1: /* compact */
189 if (!(ctx
->rflags
& RING_BUFFER_RFLAG_FULL_TSC
)) {
190 uint32_t id_time
= 0;
192 bt_bitfield_write(&id_time
, uint32_t, 0, 5, event_id
);
193 bt_bitfield_write(&id_time
, uint32_t, 5, 27, ctx
->tsc
);
194 lib_ring_buffer_write(config
, ctx
, &id_time
, sizeof(id_time
));
197 uint32_t event_id
= (uint32_t) event_id
;
198 uint64_t timestamp
= ctx
->tsc
;
200 bt_bitfield_write(&id
, uint8_t, 0, 5, 31);
201 lib_ring_buffer_write(config
, ctx
, &id
, sizeof(id
));
202 /* Align extended struct on largest member */
203 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint64_t));
204 lib_ring_buffer_write(config
, ctx
, &event_id
, sizeof(event_id
));
205 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint64_t));
206 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
211 if (!(ctx
->rflags
& RING_BUFFER_RFLAG_FULL_TSC
)) {
212 uint32_t timestamp
= (uint32_t) ctx
->tsc
;
214 lib_ring_buffer_write(config
, ctx
, &event_id
, sizeof(event_id
));
215 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint32_t));
216 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
218 uint16_t event_id
= 65535;
219 uint32_t event_id_ext
= (uint32_t) event_id
;
220 uint64_t timestamp
= ctx
->tsc
;
222 lib_ring_buffer_write(config
, ctx
, &event_id
, sizeof(event_id
));
223 /* Align extended struct on largest member */
224 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint64_t));
225 lib_ring_buffer_write(config
, ctx
, &event_id_ext
, sizeof(event_id_ext
));
226 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint64_t));
227 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
236 static const struct lib_ring_buffer_config client_config
;
238 static u64
client_ring_buffer_clock_read(struct channel
*chan
)
240 return lib_ring_buffer_clock_read(chan
);
244 size_t client_record_header_size(const struct lib_ring_buffer_config
*config
,
245 struct channel
*chan
, size_t offset
,
247 size_t *pre_header_padding
,
249 struct lib_ring_buffer_ctx
*ctx
)
251 return record_header_size(config
, chan
, offset
, data_size
,
252 pre_header_padding
, rflags
, ctx
);
256 * client_packet_header_size - called on buffer-switch to a new sub-buffer
258 * Return header size without padding after the structure. Don't use packed
259 * structure because gcc generates inefficient code on some architectures
262 static size_t client_packet_header_size(void)
264 return offsetof(struct packet_header
, ctx
.header_end
);
267 static void client_buffer_begin(struct lib_ring_buffer
*buf
, u64 tsc
,
268 unsigned int subbuf_idx
)
270 struct channel
*chan
= buf
->backend
.chan
;
271 struct packet_header
*header
=
272 (struct packet_header
*)
273 lib_ring_buffer_offset_address(&buf
->backend
,
274 subbuf_idx
* chan
->backend
.subbuf_size
);
275 struct ltt_channel
*ltt_chan
= channel_get_private(chan
);
276 struct ltt_session
*session
= ltt_chan
->session
;
278 header
->magic
= CTF_MAGIC_NUMBER
;
279 memcpy(header
->uuid
, session
->uuid
.b
, sizeof(session
->uuid
));
280 header
->stream_id
= ltt_chan
->id
;
281 header
->ctx
.timestamp_begin
= tsc
;
282 header
->ctx
.timestamp_end
= 0;
283 header
->ctx
.events_discarded
= 0;
284 header
->ctx
.content_size
= 0xFFFFFFFF; /* for debugging */
285 header
->ctx
.packet_size
= 0xFFFFFFFF;
286 header
->ctx
.cpu_id
= buf
->backend
.cpu
;
290 * offset is assumed to never be 0 here : never deliver a completely empty
291 * subbuffer. data_size is between 1 and subbuf_size.
293 static void client_buffer_end(struct lib_ring_buffer
*buf
, u64 tsc
,
294 unsigned int subbuf_idx
, unsigned long data_size
)
296 struct channel
*chan
= buf
->backend
.chan
;
297 struct packet_header
*header
=
298 (struct packet_header
*)
299 lib_ring_buffer_offset_address(&buf
->backend
,
300 subbuf_idx
* chan
->backend
.subbuf_size
);
301 unsigned long records_lost
= 0;
303 header
->ctx
.timestamp_end
= tsc
;
304 header
->ctx
.content_size
= data_size
* CHAR_BIT
; /* in bits */
305 header
->ctx
.packet_size
= PAGE_ALIGN(data_size
) * CHAR_BIT
; /* in bits */
306 records_lost
+= lib_ring_buffer_get_records_lost_full(&client_config
, buf
);
307 records_lost
+= lib_ring_buffer_get_records_lost_wrap(&client_config
, buf
);
308 records_lost
+= lib_ring_buffer_get_records_lost_big(&client_config
, buf
);
309 header
->ctx
.events_discarded
= records_lost
;
312 static int client_buffer_create(struct lib_ring_buffer
*buf
, void *priv
,
313 int cpu
, const char *name
)
318 static void client_buffer_finalize(struct lib_ring_buffer
*buf
, void *priv
, int cpu
)
322 static const struct lib_ring_buffer_config client_config
= {
323 .cb
.ring_buffer_clock_read
= client_ring_buffer_clock_read
,
324 .cb
.record_header_size
= client_record_header_size
,
325 .cb
.subbuffer_header_size
= client_packet_header_size
,
326 .cb
.buffer_begin
= client_buffer_begin
,
327 .cb
.buffer_end
= client_buffer_end
,
328 .cb
.buffer_create
= client_buffer_create
,
329 .cb
.buffer_finalize
= client_buffer_finalize
,
332 .alloc
= RING_BUFFER_ALLOC_PER_CPU
,
333 .sync
= RING_BUFFER_SYNC_PER_CPU
,
334 .mode
= RING_BUFFER_MODE_TEMPLATE
,
335 .backend
= RING_BUFFER_PAGE
,
336 .output
= RING_BUFFER_SPLICE
,
337 .oops
= RING_BUFFER_OOPS_CONSISTENCY
,
338 .ipi
= RING_BUFFER_IPI_BARRIER
,
339 .wakeup
= RING_BUFFER_WAKEUP_BY_TIMER
,
343 struct channel
*_channel_create(const char *name
,
344 struct ltt_channel
*ltt_chan
, void *buf_addr
,
345 size_t subbuf_size
, size_t num_subbuf
,
346 unsigned int switch_timer_interval
,
347 unsigned int read_timer_interval
)
349 return channel_create(&client_config
, name
, ltt_chan
, buf_addr
,
350 subbuf_size
, num_subbuf
, switch_timer_interval
,
351 read_timer_interval
);
355 void ltt_channel_destroy(struct channel
*chan
)
357 channel_destroy(chan
);
361 struct lib_ring_buffer
*ltt_buffer_read_open(struct channel
*chan
)
363 struct lib_ring_buffer
*buf
;
366 for_each_channel_cpu(cpu
, chan
) {
367 buf
= channel_get_ring_buffer(&client_config
, chan
, cpu
);
368 if (!lib_ring_buffer_open_read(buf
))
375 void ltt_buffer_read_close(struct lib_ring_buffer
*buf
)
377 lib_ring_buffer_release_read(buf
);
382 int ltt_event_reserve(struct lib_ring_buffer_ctx
*ctx
,
387 cpu
= lib_ring_buffer_get_cpu(&client_config
);
392 ret
= lib_ring_buffer_reserve(&client_config
, ctx
);
395 ltt_write_event_header(&client_config
, ctx
, event_id
);
398 lib_ring_buffer_put_cpu(&client_config
);
403 void ltt_event_commit(struct lib_ring_buffer_ctx
*ctx
)
405 lib_ring_buffer_commit(&client_config
, ctx
);
406 lib_ring_buffer_put_cpu(&client_config
);
410 void ltt_event_write(struct lib_ring_buffer_ctx
*ctx
, const void *src
,
413 lib_ring_buffer_write(&client_config
, ctx
, src
, len
);
417 wait_queue_head_t
*ltt_get_reader_wait_queue(struct ltt_channel
*chan
)
419 return &chan
->chan
->read_wait
;
422 static struct ltt_transport ltt_relay_transport
= {
423 .name
= "relay-" RING_BUFFER_MODE_TEMPLATE_STRING
,
424 .owner
= THIS_MODULE
,
426 .channel_create
= _channel_create
,
427 .channel_destroy
= ltt_channel_destroy
,
428 .buffer_read_open
= ltt_buffer_read_open
,
429 .buffer_read_close
= ltt_buffer_read_close
,
430 .event_reserve
= ltt_event_reserve
,
431 .event_commit
= ltt_event_commit
,
432 .event_write
= ltt_event_write
,
433 .packet_avail_size
= NULL
, /* Would be racy anyway */
434 .get_reader_wait_queue
= ltt_get_reader_wait_queue
,
438 static int __init
ltt_ring_buffer_client_init(void)
441 * This vmalloc sync all also takes care of the lib ring buffer
442 * vmalloc'd module pages when it is built as a module into LTTng.
444 wrapper_vmalloc_sync_all();
445 printk(KERN_INFO
"LTT : ltt ring buffer client init\n");
446 ltt_transport_register(<t_relay_transport
);
450 module_init(ltt_ring_buffer_client_init
);
452 static void __exit
ltt_ring_buffer_client_exit(void)
454 printk(KERN_INFO
"LTT : ltt ring buffer client exit\n");
455 ltt_transport_unregister(<t_relay_transport
);
458 module_exit(ltt_ring_buffer_client_exit
);
460 MODULE_LICENSE("GPL and additional rights");
461 MODULE_AUTHOR("Mathieu Desnoyers");
462 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING