4 * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6 * Holds LTTng per-session event registry.
8 * Dual LGPL v2.1/GPL v2 license.
14 #include <urcu/list.h>
15 #include <urcu/hlist.h>
17 #include <uuid/uuid.h>
28 #include <urcu/compiler.h>
29 #include <urcu/uatomic.h>
30 #include <urcu/arch.h>
32 #include <lttng/tracepoint.h>
33 #include <lttng/ust-events.h>
35 #include <usterr-signal-safe.h>
39 #include "ltt-tracer.h"
40 #include "ltt-tracer-core.h"
42 #include "../libringbuffer/shm.h"
46 * The sessions mutex is the centralized mutex across UST tracing
47 * control and probe registration. All operations within this file are
48 * called by the communication thread, under ust_lock protection.
50 static pthread_mutex_t sessions_mutex
= PTHREAD_MUTEX_INITIALIZER
;
54 pthread_mutex_lock(&sessions_mutex
);
59 pthread_mutex_unlock(&sessions_mutex
);
62 static CDS_LIST_HEAD(sessions
);
65 * Pending probes hash table, containing the registered ltt events for
66 * which tracepoint probes are still missing. Protected by the sessions
69 #define PENDING_PROBE_HASH_BITS 6
70 #define PENDING_PROBE_HASH_SIZE (1 << PENDING_PROBE_HASH_BITS)
71 static struct cds_hlist_head pending_probe_table
[PENDING_PROBE_HASH_SIZE
];
73 struct ust_pending_probe
{
74 struct ltt_event
*event
;
75 struct cds_hlist_node node
;
79 static void _ltt_event_destroy(struct ltt_event
*event
);
80 static void _ltt_wildcard_destroy(struct session_wildcard
*sw
);
81 static void _ltt_channel_destroy(struct ltt_channel
*chan
);
82 static int _ltt_event_unregister(struct ltt_event
*event
);
84 int _ltt_event_metadata_statedump(struct ltt_session
*session
,
85 struct ltt_channel
*chan
,
86 struct ltt_event
*event
);
88 int _ltt_session_metadata_statedump(struct ltt_session
*session
);
91 * called at event creation if probe is missing.
92 * called with session mutex held.
95 int add_pending_probe(struct ltt_event
*event
, const char *name
)
97 struct cds_hlist_head
*head
;
98 struct ust_pending_probe
*e
;
99 size_t name_len
= strlen(name
);
102 if (name_len
> LTTNG_UST_SYM_NAME_LEN
- 1) {
103 WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name
, LTTNG_UST_SYM_NAME_LEN
- 1);
104 name_len
= LTTNG_UST_SYM_NAME_LEN
- 1;
106 hash
= jhash(name
, name_len
, 0);
107 head
= &pending_probe_table
[hash
& (PENDING_PROBE_HASH_SIZE
- 1)];
108 e
= zmalloc(sizeof(struct ust_pending_probe
) + name_len
);
111 memcpy(&e
->name
[0], name
, name_len
+ 1);
112 e
->name
[name_len
] = '\0';
113 cds_hlist_add_head(&e
->node
, head
);
115 event
->pending_probe
= e
;
120 * remove a pending probe. called when at event teardown and when an
121 * event is fixed (probe is loaded).
122 * called with session mutex held.
125 void remove_pending_probe(struct ust_pending_probe
*e
)
129 cds_hlist_del(&e
->node
);
134 * Called at library load: connect the probe on the events pending on
136 * called with session mutex held.
138 int pending_probe_fix_events(const struct lttng_event_desc
*desc
)
140 struct cds_hlist_head
*head
;
141 struct cds_hlist_node
*node
, *p
;
142 struct ust_pending_probe
*e
;
143 const char *name
= desc
->name
;
145 struct lttng_ust_event event_param
;
146 size_t name_len
= strlen(name
);
151 struct wildcard_entry
*wildcard
;
153 /* TODO: get value from loglevel. */
155 /* TODO: check if loglevel match */
156 wildcard
= match_wildcard(desc
->name
);
157 if (strcmp(desc
->name
, "lttng_ust:metadata") && wildcard
) {
158 struct session_wildcard
*sw
;
160 cds_list_for_each_entry(sw
, &wildcard
->session_list
,
162 struct ltt_event
*ev
;
165 memcpy(&event_param
, &sw
->event_param
,
166 sizeof(event_param
));
167 memcpy(event_param
.name
,
169 sizeof(event_param
.name
));
171 ret
= ltt_event_create(sw
->chan
,
175 DBG("Error creating event");
178 cds_list_add(&ev
->wildcard_list
,
184 if (name_len
> LTTNG_UST_SYM_NAME_LEN
- 1) {
185 WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name
, LTTNG_UST_SYM_NAME_LEN
- 1);
186 name_len
= LTTNG_UST_SYM_NAME_LEN
- 1;
188 hash
= jhash(name
, name_len
, 0);
189 head
= &pending_probe_table
[hash
& (PENDING_PROBE_HASH_SIZE
- 1)];
190 cds_hlist_for_each_entry_safe(e
, node
, p
, head
, node
) {
191 struct ltt_event
*event
;
192 struct ltt_channel
*chan
;
194 /* TODO: get value from loglevel. */
196 /* TODO: check if loglevel match */
197 if (strncmp(name
, e
->name
, LTTNG_UST_SYM_NAME_LEN
- 1))
201 assert(!event
->desc
);
203 event
->pending_probe
= NULL
;
204 remove_pending_probe(e
);
205 ret
|= __tracepoint_probe_register(name
,
206 event
->desc
->probe_callback
,
210 event
->id
= chan
->free_event_id
++;
211 ret
|= _ltt_event_metadata_statedump(chan
->session
, chan
,
217 void synchronize_trace(void)
222 struct ltt_session
*ltt_session_create(void)
224 struct ltt_session
*session
;
226 session
= zmalloc(sizeof(struct ltt_session
));
229 CDS_INIT_LIST_HEAD(&session
->chan
);
230 CDS_INIT_LIST_HEAD(&session
->events
);
231 CDS_INIT_LIST_HEAD(&session
->wildcards
);
232 uuid_generate(session
->uuid
);
233 cds_list_add(&session
->list
, &sessions
);
237 void ltt_session_destroy(struct ltt_session
*session
)
239 struct ltt_channel
*chan
, *tmpchan
;
240 struct ltt_event
*event
, *tmpevent
;
241 struct session_wildcard
*wildcard
, *tmpwildcard
;
244 CMM_ACCESS_ONCE(session
->active
) = 0;
245 cds_list_for_each_entry(event
, &session
->events
, list
) {
246 ret
= _ltt_event_unregister(event
);
249 synchronize_trace(); /* Wait for in-flight events to complete */
250 cds_list_for_each_entry_safe(wildcard
, tmpwildcard
, &session
->wildcards
, list
)
251 _ltt_wildcard_destroy(wildcard
);
252 cds_list_for_each_entry_safe(event
, tmpevent
, &session
->events
, list
)
253 _ltt_event_destroy(event
);
254 cds_list_for_each_entry_safe(chan
, tmpchan
, &session
->chan
, list
)
255 _ltt_channel_destroy(chan
);
256 cds_list_del(&session
->list
);
260 int ltt_session_enable(struct ltt_session
*session
)
263 struct ltt_channel
*chan
;
265 if (session
->active
) {
271 * Snapshot the number of events per channel to know the type of header
274 cds_list_for_each_entry(chan
, &session
->chan
, list
) {
275 if (chan
->header_type
)
276 continue; /* don't change it if session stop/restart */
277 if (chan
->free_event_id
< 31)
278 chan
->header_type
= 1; /* compact */
280 chan
->header_type
= 2; /* large */
283 CMM_ACCESS_ONCE(session
->active
) = 1;
284 CMM_ACCESS_ONCE(session
->been_active
) = 1;
285 ret
= _ltt_session_metadata_statedump(session
);
287 CMM_ACCESS_ONCE(session
->active
) = 0;
292 int ltt_session_disable(struct ltt_session
*session
)
296 if (!session
->active
) {
300 CMM_ACCESS_ONCE(session
->active
) = 0;
305 int ltt_channel_enable(struct ltt_channel
*channel
)
309 if (channel
== channel
->session
->metadata
)
311 old
= uatomic_xchg(&channel
->enabled
, 1);
317 int ltt_channel_disable(struct ltt_channel
*channel
)
321 if (channel
== channel
->session
->metadata
)
323 old
= uatomic_xchg(&channel
->enabled
, 0);
329 int ltt_event_enable(struct ltt_event
*event
)
333 if (event
->chan
== event
->chan
->session
->metadata
)
335 old
= uatomic_xchg(&event
->enabled
, 1);
341 int ltt_event_disable(struct ltt_event
*event
)
345 if (event
->chan
== event
->chan
->session
->metadata
)
347 old
= uatomic_xchg(&event
->enabled
, 0);
353 struct ltt_channel
*ltt_channel_create(struct ltt_session
*session
,
354 const char *transport_name
,
356 size_t subbuf_size
, size_t num_subbuf
,
357 unsigned int switch_timer_interval
,
358 unsigned int read_timer_interval
,
359 int **shm_fd
, int **wait_fd
,
360 uint64_t **memory_map_size
,
361 struct ltt_channel
*chan_priv_init
)
363 struct ltt_channel
*chan
= NULL
;
364 struct ltt_transport
*transport
;
366 if (session
->been_active
)
367 goto active
; /* Refuse to add channel to active session */
368 transport
= ltt_transport_find(transport_name
);
370 DBG("LTTng transport %s not found\n",
374 chan_priv_init
->id
= session
->free_chan_id
++;
375 chan_priv_init
->session
= session
;
377 * Note: the channel creation op already writes into the packet
378 * headers. Therefore the "chan" information used as input
379 * should be already accessible.
381 chan
= transport
->ops
.channel_create("[lttng]", buf_addr
,
382 subbuf_size
, num_subbuf
, switch_timer_interval
,
383 read_timer_interval
, shm_fd
, wait_fd
,
384 memory_map_size
, chan_priv_init
);
388 chan
->ops
= &transport
->ops
;
389 cds_list_add(&chan
->list
, &session
->chan
);
399 * Only used internally at session destruction.
402 void _ltt_channel_destroy(struct ltt_channel
*chan
)
404 cds_list_del(&chan
->list
);
405 lttng_destroy_context(chan
->ctx
);
406 chan
->ops
->channel_destroy(chan
);
409 int ltt_wildcard_create(struct ltt_channel
*chan
,
410 struct lttng_ust_event
*event_param
,
411 struct session_wildcard
**_sw
)
413 struct session_wildcard
*sw
;
415 sw
= add_wildcard(event_param
->name
, chan
, event_param
);
416 if (!sw
|| IS_ERR(sw
)) {
424 void _ltt_wildcard_destroy(struct session_wildcard
*sw
)
426 _remove_wildcard(sw
);
430 * Supports event creation while tracing session is active.
432 int ltt_event_create(struct ltt_channel
*chan
,
433 struct lttng_ust_event
*event_param
,
435 struct ltt_event
**_event
)
437 struct ltt_event
*event
;
440 if (chan
->used_event_id
== -1UL) {
445 * This is O(n^2) (for each event, the loop is called at event
446 * creation). Might require a hash if we have lots of events.
448 cds_list_for_each_entry(event
, &chan
->session
->events
, list
) {
449 if (event
->desc
&& !strncmp(event
->desc
->name
,
451 LTTNG_UST_SYM_NAME_LEN
- 1)) {
456 event
= zmalloc(sizeof(struct ltt_event
));
462 event
->filter
= filter
;
464 * used_event_id counts the maximum number of event IDs that can
465 * register if all probes register.
467 chan
->used_event_id
++;
469 event
->instrumentation
= event_param
->instrumentation
;
470 /* Populate ltt_event structure before tracepoint registration. */
472 switch (event_param
->instrumentation
) {
473 case LTTNG_UST_TRACEPOINT
:
474 event
->desc
= ltt_event_get(event_param
->name
);
475 /* TODO: get value from loglevel. */
477 /* TODO: check if loglevel match */
479 ret
= __tracepoint_probe_register(event_param
->name
,
480 event
->desc
->probe_callback
,
484 event
->id
= chan
->free_event_id
++;
487 * If the probe is not present, event->desc stays NULL,
488 * waiting for the probe to register, and the event->id
491 ret
= add_pending_probe(event
, event_param
->name
);
493 goto add_pending_error
;
500 ret
= _ltt_event_metadata_statedump(chan
->session
, chan
, event
);
502 goto statedump_error
;
504 cds_list_add(&event
->list
, &chan
->session
->events
);
510 WARN_ON_ONCE(__tracepoint_probe_unregister(event_param
->name
,
511 event
->desc
->probe_callback
,
513 ltt_event_put(event
->desc
);
525 * Only used internally at session destruction.
527 int _ltt_event_unregister(struct ltt_event
*event
)
531 switch (event
->instrumentation
) {
532 case LTTNG_UST_TRACEPOINT
:
534 ret
= __tracepoint_probe_unregister(event
->desc
->name
,
535 event
->desc
->probe_callback
,
540 remove_pending_probe(event
->pending_probe
);
551 * Only used internally at session destruction.
554 void _ltt_event_destroy(struct ltt_event
*event
)
556 switch (event
->instrumentation
) {
557 case LTTNG_UST_TRACEPOINT
:
559 ltt_event_put(event
->desc
);
565 cds_list_del(&event
->list
);
566 lttng_destroy_context(event
->ctx
);
571 * We have exclusive access to our metadata buffer (protected by the
572 * ust_lock), so we can do racy operations such as looking for
573 * remaining space left in packet and write, since mutual exclusion
574 * protects us from concurrent writes.
576 int lttng_metadata_printf(struct ltt_session
*session
,
577 const char *fmt
, ...)
579 struct lttng_ust_lib_ring_buffer_ctx ctx
;
580 struct ltt_channel
*chan
= session
->metadata
;
582 int ret
= 0, waitret
;
583 size_t len
, reserve_len
, pos
;
586 WARN_ON_ONCE(!CMM_ACCESS_ONCE(session
->active
));
589 ret
= vasprintf(&str
, fmt
, ap
);
597 for (pos
= 0; pos
< len
; pos
+= reserve_len
) {
598 reserve_len
= min_t(size_t,
599 chan
->ops
->packet_avail_size(chan
->chan
, chan
->handle
),
601 lib_ring_buffer_ctx_init(&ctx
, chan
->chan
, NULL
, reserve_len
,
602 sizeof(char), -1, chan
->handle
);
604 * We don't care about metadata buffer's records lost
605 * count, because we always retry here. Report error if
606 * we need to bail out after timeout or being
609 waitret
= wait_cond_interruptible_timeout(
611 ret
= chan
->ops
->event_reserve(&ctx
, 0);
612 ret
!= -ENOBUFS
|| !ret
;
614 LTTNG_METADATA_TIMEOUT_MSEC
);
615 if (waitret
== -ETIMEDOUT
|| waitret
== -EINTR
|| ret
) {
616 DBG("LTTng: Failure to write metadata to buffers (%s)\n",
617 waitret
== -EINTR
? "interrupted" :
618 (ret
== -ENOBUFS
? "timeout" : "I/O error"));
619 if (waitret
== -EINTR
)
623 chan
->ops
->event_write(&ctx
, &str
[pos
], reserve_len
);
624 chan
->ops
->event_commit(&ctx
);
632 int _ltt_field_statedump(struct ltt_session
*session
,
633 const struct lttng_event_field
*field
)
637 switch (field
->type
.atype
) {
639 ret
= lttng_metadata_printf(session
,
640 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
641 field
->type
.u
.basic
.integer
.size
,
642 field
->type
.u
.basic
.integer
.alignment
,
643 field
->type
.u
.basic
.integer
.signedness
,
644 (field
->type
.u
.basic
.integer
.encoding
== lttng_encode_none
)
646 : (field
->type
.u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
649 field
->type
.u
.basic
.integer
.base
,
650 #if (BYTE_ORDER == BIG_ENDIAN)
651 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
653 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
658 ret
= lttng_metadata_printf(session
,
659 " floating_point { exp_dig = %u; mant_dig = %u; align = %u;%s } _%s;\n",
660 field
->type
.u
.basic
._float
.exp_dig
,
661 field
->type
.u
.basic
._float
.mant_dig
,
662 field
->type
.u
.basic
._float
.alignment
,
663 #if (BYTE_ORDER == BIG_ENDIAN)
664 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
666 field
->type
.u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
671 ret
= lttng_metadata_printf(session
,
673 field
->type
.u
.basic
.enumeration
.name
,
678 const struct lttng_basic_type
*elem_type
;
680 elem_type
= &field
->type
.u
.array
.elem_type
;
681 ret
= lttng_metadata_printf(session
,
682 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
683 elem_type
->u
.basic
.integer
.size
,
684 elem_type
->u
.basic
.integer
.alignment
,
685 elem_type
->u
.basic
.integer
.signedness
,
686 (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
688 : (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
691 elem_type
->u
.basic
.integer
.base
,
692 #if (BYTE_ORDER == BIG_ENDIAN)
693 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
695 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
697 field
->name
, field
->type
.u
.array
.length
);
702 const struct lttng_basic_type
*elem_type
;
703 const struct lttng_basic_type
*length_type
;
705 elem_type
= &field
->type
.u
.sequence
.elem_type
;
706 length_type
= &field
->type
.u
.sequence
.length_type
;
707 ret
= lttng_metadata_printf(session
,
708 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
709 length_type
->u
.basic
.integer
.size
,
710 (unsigned int) length_type
->u
.basic
.integer
.alignment
,
711 length_type
->u
.basic
.integer
.signedness
,
712 (length_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
714 : ((length_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
717 length_type
->u
.basic
.integer
.base
,
718 #if (BYTE_ORDER == BIG_ENDIAN)
719 length_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
721 length_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
727 ret
= lttng_metadata_printf(session
,
728 " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
729 elem_type
->u
.basic
.integer
.size
,
730 (unsigned int) elem_type
->u
.basic
.integer
.alignment
,
731 elem_type
->u
.basic
.integer
.signedness
,
732 (elem_type
->u
.basic
.integer
.encoding
== lttng_encode_none
)
734 : ((elem_type
->u
.basic
.integer
.encoding
== lttng_encode_UTF8
)
737 elem_type
->u
.basic
.integer
.base
,
738 #if (BYTE_ORDER == BIG_ENDIAN)
739 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = le;" : "",
741 elem_type
->u
.basic
.integer
.reverse_byte_order
? " byte_order = be;" : "",
749 /* Default encoding is UTF8 */
750 ret
= lttng_metadata_printf(session
,
752 field
->type
.u
.basic
.string
.encoding
== lttng_encode_ASCII
?
753 " { encoding = ASCII; }" : "",
764 int _ltt_context_metadata_statedump(struct ltt_session
*session
,
765 struct lttng_ctx
*ctx
)
772 for (i
= 0; i
< ctx
->nr_fields
; i
++) {
773 const struct lttng_ctx_field
*field
= &ctx
->fields
[i
];
775 ret
= _ltt_field_statedump(session
, &field
->event_field
);
783 int _ltt_fields_metadata_statedump(struct ltt_session
*session
,
784 struct ltt_event
*event
)
786 const struct lttng_event_desc
*desc
= event
->desc
;
790 for (i
= 0; i
< desc
->nr_fields
; i
++) {
791 const struct lttng_event_field
*field
= &desc
->fields
[i
];
793 ret
= _ltt_field_statedump(session
, field
);
801 int _ltt_event_metadata_statedump(struct ltt_session
*session
,
802 struct ltt_channel
*chan
,
803 struct ltt_event
*event
)
807 if (event
->metadata_dumped
|| !CMM_ACCESS_ONCE(session
->active
))
809 if (chan
== session
->metadata
)
812 * Don't print events for which probe load is pending.
817 ret
= lttng_metadata_printf(session
,
821 " stream_id = %u;\n",
828 if (event
->desc
->loglevel
) {
829 const struct tracepoint_loglevel_entry
*ll_entry
;
831 ll_entry
= *event
->desc
->loglevel
;
832 ret
= lttng_metadata_printf(session
,
833 " loglevel.identifier = \"%s\";\n"
834 " loglevel.value = %lld;\n",
835 ll_entry
->identifier
,
836 (long long) ll_entry
->value
);
842 ret
= lttng_metadata_printf(session
,
843 " context := struct {\n");
847 ret
= _ltt_context_metadata_statedump(session
, event
->ctx
);
851 ret
= lttng_metadata_printf(session
,
857 ret
= lttng_metadata_printf(session
,
858 " fields := struct {\n"
863 ret
= _ltt_fields_metadata_statedump(session
, event
);
868 * LTTng space reservation can only reserve multiples of the
871 ret
= lttng_metadata_printf(session
,
877 event
->metadata_dumped
= 1;
884 int _ltt_channel_metadata_statedump(struct ltt_session
*session
,
885 struct ltt_channel
*chan
)
889 if (chan
->metadata_dumped
|| !CMM_ACCESS_ONCE(session
->active
))
891 if (chan
== session
->metadata
)
894 WARN_ON_ONCE(!chan
->header_type
);
895 ret
= lttng_metadata_printf(session
,
898 " event.header := %s;\n"
899 " packet.context := struct packet_context;\n",
901 chan
->header_type
== 1 ? "struct event_header_compact" :
902 "struct event_header_large");
907 ret
= lttng_metadata_printf(session
,
908 " event.context := struct {\n");
912 ret
= _ltt_context_metadata_statedump(session
, chan
->ctx
);
916 ret
= lttng_metadata_printf(session
,
922 ret
= lttng_metadata_printf(session
,
925 chan
->metadata_dumped
= 1;
931 int _ltt_stream_packet_context_declare(struct ltt_session
*session
)
933 return lttng_metadata_printf(session
,
934 "struct packet_context {\n"
935 " uint64_clock_monotonic_t timestamp_begin;\n"
936 " uint64_clock_monotonic_t timestamp_end;\n"
937 " uint32_t events_discarded;\n"
938 " uint32_t content_size;\n"
939 " uint32_t packet_size;\n"
940 " uint32_t cpu_id;\n"
948 * id 31 is reserved to indicate an extended header.
951 * id: range: 0 - 65534.
952 * id 65535 is reserved to indicate an extended header.
955 int _ltt_event_header_declare(struct ltt_session
*session
)
957 return lttng_metadata_printf(session
,
958 "struct event_header_compact {\n"
959 " enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
962 " uint27_clock_monotonic_t timestamp;\n"
966 " uint64_clock_monotonic_t timestamp;\n"
971 "struct event_header_large {\n"
972 " enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
975 " uint32_clock_monotonic_t timestamp;\n"
979 " uint64_clock_monotonic_t timestamp;\n"
983 lttng_alignof(uint32_t) * CHAR_BIT
,
984 lttng_alignof(uint16_t) * CHAR_BIT
989 * Approximation of NTP time of day to clock monotonic correlation,
990 * taken at start of trace.
991 * Yes, this is only an approximation. Yes, we can (and will) do better
992 * in future versions.
995 uint64_t measure_clock_offset(void)
997 uint64_t offset
, monotonic
[2], realtime
;
998 struct timespec rts
= { 0, 0 };
1001 monotonic
[0] = trace_clock_read64();
1002 ret
= clock_gettime(CLOCK_REALTIME
, &rts
);
1005 monotonic
[1] = trace_clock_read64();
1006 offset
= (monotonic
[0] + monotonic
[1]) >> 1;
1007 realtime
= rts
.tv_sec
* 1000000000ULL;
1008 realtime
+= rts
.tv_nsec
;
1009 offset
= realtime
- offset
;
1014 * Output metadata into this session's metadata buffers.
1017 int _ltt_session_metadata_statedump(struct ltt_session
*session
)
1019 unsigned char *uuid_c
= session
->uuid
;
1020 char uuid_s
[37], clock_uuid_s
[CLOCK_UUID_LEN
];
1021 struct ltt_channel
*chan
;
1022 struct ltt_event
*event
;
1025 if (!CMM_ACCESS_ONCE(session
->active
))
1027 if (session
->metadata_dumped
)
1029 if (!session
->metadata
) {
1030 DBG("LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
1034 snprintf(uuid_s
, sizeof(uuid_s
),
1035 "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
1036 uuid_c
[0], uuid_c
[1], uuid_c
[2], uuid_c
[3],
1037 uuid_c
[4], uuid_c
[5], uuid_c
[6], uuid_c
[7],
1038 uuid_c
[8], uuid_c
[9], uuid_c
[10], uuid_c
[11],
1039 uuid_c
[12], uuid_c
[13], uuid_c
[14], uuid_c
[15]);
1041 ret
= lttng_metadata_printf(session
,
1042 "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
1043 "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
1044 "typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
1045 "typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
1046 "typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
1047 "typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
1053 " byte_order = %s;\n"
1054 " packet.header := struct {\n"
1055 " uint32_t magic;\n"
1056 " uint8_t uuid[16];\n"
1057 " uint32_t stream_id;\n"
1060 lttng_alignof(uint8_t) * CHAR_BIT
,
1061 lttng_alignof(uint16_t) * CHAR_BIT
,
1062 lttng_alignof(uint32_t) * CHAR_BIT
,
1063 lttng_alignof(uint64_t) * CHAR_BIT
,
1067 #if (BYTE_ORDER == BIG_ENDIAN)
1076 ret
= lttng_metadata_printf(session
,
1084 if (!trace_clock_uuid(clock_uuid_s
)) {
1085 ret
= lttng_metadata_printf(session
,
1086 " uuid = \"%s\";\n",
1093 ret
= lttng_metadata_printf(session
,
1094 " description = \"Monotonic Clock\";\n"
1095 " freq = %" PRIu64
"; /* Frequency, in Hz */\n"
1096 " /* clock value offset from Epoch is: offset * (1/freq) */\n"
1097 " offset = %" PRIu64
";\n"
1100 measure_clock_offset()
1105 ret
= lttng_metadata_printf(session
,
1106 "typealias integer {\n"
1107 " size = 27; align = 1; signed = false;\n"
1108 " map = clock.monotonic.value;\n"
1109 "} := uint27_clock_monotonic_t;\n"
1111 "typealias integer {\n"
1112 " size = 32; align = %u; signed = false;\n"
1113 " map = clock.monotonic.value;\n"
1114 "} := uint32_clock_monotonic_t;\n"
1116 "typealias integer {\n"
1117 " size = 64; align = %u; signed = false;\n"
1118 " map = clock.monotonic.value;\n"
1119 "} := uint64_clock_monotonic_t;\n\n",
1120 lttng_alignof(uint32_t) * CHAR_BIT
,
1121 lttng_alignof(uint64_t) * CHAR_BIT
1126 ret
= _ltt_stream_packet_context_declare(session
);
1130 ret
= _ltt_event_header_declare(session
);
1135 cds_list_for_each_entry(chan
, &session
->chan
, list
) {
1136 ret
= _ltt_channel_metadata_statedump(session
, chan
);
1141 cds_list_for_each_entry(event
, &session
->events
, list
) {
1142 ret
= _ltt_event_metadata_statedump(session
, event
->chan
, event
);
1146 session
->metadata_dumped
= 1;
1151 void lttng_ust_events_exit(void)
1153 struct ltt_session
*session
, *tmpsession
;
1155 cds_list_for_each_entry_safe(session
, tmpsession
, &sessions
, list
)
1156 ltt_session_destroy(session
);