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
,
129 u16 eID
, u32 event_size
);
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
139 * @event_size : size of the event, excluding the event header.
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
)
146 struct ltt_channel
*ltt_chan
= channel_get_private(ctx
->chan
);
148 if (unlikely(ctx
->rflags
))
151 switch (ltt_chan
->header_type
) {
152 case 1: /* compact */
154 uint32_t id_time
= 0;
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
));
163 uint16_t event_id
= eID
;
164 uint32_t timestamp
= (uint32_t) ctx
->tsc
;
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
));
177 ltt_write_event_header_slow(config
, ctx
, eID
, event_size
);
181 * TODO: For now, we only support 65536 event ids per channel.
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
)
187 struct ltt_channel
*ltt_chan
= channel_get_private(ctx
->chan
);
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;
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
));
199 uint32_t event_id
= (uint32_t) eID
;
200 uint64_t timestamp
= ctx
->tsc
;
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
));
213 if (!(ctx
->rflags
& RING_BUFFER_RFLAG_FULL_TSC
)) {
214 uint16_t event_id
= eID
;
215 uint32_t timestamp
= (uint32_t) ctx
->tsc
;
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
));
221 uint16_t event_id
= 65535;
222 uint32_t event_id_ext
= (uint32_t) eID
;
223 uint64_t timestamp
= ctx
->tsc
;
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
));
239 static const struct lib_ring_buffer_config client_config
;
241 static u64
client_ring_buffer_clock_read(struct channel
*chan
)
243 return lib_ring_buffer_clock_read(chan
);
247 size_t client_record_header_size(const struct lib_ring_buffer_config
*config
,
248 struct channel
*chan
, size_t offset
,
250 size_t *pre_header_padding
,
252 struct lib_ring_buffer_ctx
*ctx
)
254 return record_header_size(config
, chan
, offset
, data_size
,
255 pre_header_padding
, rflags
, ctx
);
259 * client_packet_header_size - called on buffer-switch to a new sub-buffer
261 * Return header size without padding after the structure. Don't use packed
262 * structure because gcc generates inefficient code on some architectures
265 static size_t client_packet_header_size(void)
267 return offsetof(struct packet_header
, ctx
.header_end
);
270 static void client_buffer_begin(struct lib_ring_buffer
*buf
, u64 tsc
,
271 unsigned int subbuf_idx
)
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
;
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
;
293 * offset is assumed to never be 0 here : never deliver a completely empty
294 * subbuffer. data_size is between 1 and subbuf_size.
296 static void client_buffer_end(struct lib_ring_buffer
*buf
, u64 tsc
,
297 unsigned int subbuf_idx
, unsigned long data_size
)
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;
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
;
315 static int client_buffer_create(struct lib_ring_buffer
*buf
, void *priv
,
316 int cpu
, const char *name
)
321 static void client_buffer_finalize(struct lib_ring_buffer
*buf
, void *priv
, int cpu
)
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
,
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
,
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
)
352 return channel_create(&client_config
, name
, ltt_chan
, buf_addr
,
353 subbuf_size
, num_subbuf
, switch_timer_interval
,
354 read_timer_interval
);
358 void ltt_channel_destroy(struct channel
*chan
)
360 channel_destroy(chan
);
364 struct lib_ring_buffer
*ltt_buffer_read_open(struct channel
*chan
)
366 struct lib_ring_buffer
*buf
;
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
))
378 void ltt_buffer_read_close(struct lib_ring_buffer
*buf
)
380 lib_ring_buffer_release_read(buf
);
385 int ltt_event_reserve(struct lib_ring_buffer_ctx
*ctx
)
389 cpu
= lib_ring_buffer_get_cpu(&client_config
);
394 ret
= lib_ring_buffer_reserve(&client_config
, ctx
);
400 lib_ring_buffer_put_cpu(&client_config
);
405 void ltt_event_commit(struct lib_ring_buffer_ctx
*ctx
)
407 lib_ring_buffer_commit(&client_config
, ctx
);
408 lib_ring_buffer_put_cpu(&client_config
);
412 void ltt_event_write(struct lib_ring_buffer_ctx
*ctx
, const void *src
,
415 lib_ring_buffer_write(&client_config
, ctx
, src
, len
);
419 wait_queue_head_t
*ltt_get_reader_wait_queue(struct ltt_channel
*chan
)
421 return &chan
->chan
->read_wait
;
424 static struct ltt_transport ltt_relay_transport
= {
425 .name
= "relay-" RING_BUFFER_MODE_TEMPLATE_STRING
,
426 .owner
= THIS_MODULE
,
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
,
440 static int __init
ltt_ring_buffer_client_init(void)
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.
446 wrapper_vmalloc_sync_all();
447 printk(KERN_INFO
"LTT : ltt ring buffer client init\n");
448 ltt_transport_register(<t_relay_transport
);
452 module_init(ltt_ring_buffer_client_init
);
454 static void __exit
ltt_ring_buffer_client_exit(void)
456 printk(KERN_INFO
"LTT : ltt ring buffer client exit\n");
457 ltt_transport_unregister(<t_relay_transport
);
460 module_exit(ltt_ring_buffer_client_exit
);
462 MODULE_LICENSE("GPL and additional rights");
463 MODULE_AUTHOR("Mathieu Desnoyers");
464 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING