1 .TH "LTTNG" "1" "February 05th, 2014" "" ""
4 lttng \(em LTTng 2.x tracer control command line tool
9 lttng [OPTIONS] <COMMAND>
13 The LTTng project aims at providing highly efficient tracing tools for Linux.
14 Its tracers help track down performance issues and debug problems
15 involving multiple concurrent processes and threads. Tracing across multiple
16 systems is also possible.
18 The \fBlttng\fP command line tool from the lttng-tools package is used to control
19 both kernel and user-space tracing. Every interaction with the tracer should
20 be done by this tool or by the liblttng-ctl library provided by the lttng-tools
23 LTTng uses a session daemon (lttng-sessiond(8)), acting as a tracing registry,
24 which allows you to interact with multiple tracers (kernel and user-space)
25 inside the same container, a tracing session. Traces can be gathered from the
26 kernel and/or instrumented applications (lttng-ust(3)). Aggregating and reading
27 those traces is done using the babeltrace(1) text viewer.
29 We introduce the notion of \fBtracing domains\fP which is essentially a type of
30 tracer (kernel, user space or JUL for now). In the future, we could see more
31 tracer like for instance an hypervisor. For some commands, you'll need to
32 specify on which domain the command operates (\-u, \-k or \-j). For instance,
33 the kernel domain must be specified when enabling a kernel event.
35 In order to trace the kernel, the session daemon needs to be running as root.
36 LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is
37 in that group can interact with the root session daemon and thus trace the
38 kernel. Session daemons can co-exist, meaning that you can have a session daemon
39 running as Alice that can be used to trace her applications along side with a
40 root daemon or even a Bob daemon. We highly recommend starting the session
41 daemon at boot time for stable and long term tracing.
43 All user-space applications instrumented with lttng-ust(3) will
44 automatically register to the session daemon. This feature gives you the
45 ability to list available traceable applications and tracepoints on a per user
46 basis. (See \fBlist\fP command).
50 This program follow the usual GNU command line syntax with long options starting with
51 two dashes. Below is a summary of the available options.
56 Show summary of possible options and commands.
58 .BR "\-v, \-\-verbose"
60 Three levels of verbosity are available which are triggered by putting additional v to
61 the option (\-vv or \-vvv)
64 Suppress all messages (even errors).
66 .BR "\-g, \-\-group NAME"
67 Set unix tracing group name. (default: tracing)
69 .BR "\-n, \-\-no-sessiond"
70 Don't automatically spawn a session daemon.
72 .BR "\-\-sessiond\-path PATH"
73 Set session daemon full binary path.
75 .BR "\-\-list\-options"
76 Simple listing of lttng options.
78 .BR "\-\-list\-commands"
79 Simple listing of lttng commands.
83 \fBadd-context\fP [OPTIONS]
85 Add context to event(s) and/or channel(s).
87 A context is basically extra information appended to a channel. For instance,
88 you could ask the tracer to add the PID information for all events in a
89 channel. You can also add performance monitoring unit counters (perf PMU) using
92 For example, this command will add the context information 'prio' and two perf
93 counters (hardware branch misses and cache misses), to all events in the trace
97 # lttng add-context \-k \-t prio \-t perf:branch-misses \\
101 Please take a look at the help (\-h/\-\-help) for a detailed list of available
104 If no channel is given (\-c), the context is added to all channels that were
105 already enabled. If the session has no channel, a default channel is created.
106 Otherwise the context will be added only to the given channel (\-c).
108 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
115 Show summary of possible options and commands.
117 .BR "\-s, \-\-session NAME"
118 Apply on session name.
120 .BR "\-c, \-\-channel NAME"
121 Apply on channel name.
123 .BR "\-k, \-\-kernel"
124 Apply for the kernel tracer
126 .BR "\-u, \-\-userspace"
127 Apply for the user-space tracer
129 .BR "\-t, \-\-type TYPE"
130 Context type. You can repeat this option on the command line. Please
131 use "lttng add-context \-h" to list all available types.
136 \fBcalibrate\fP [OPTIONS]
138 Quantify LTTng overhead
140 The LTTng calibrate command can be used to find out the combined average
141 overhead of the LTTng tracer and the instrumentation mechanisms used. This
142 overhead can be calibrated in terms of time or using any of the PMU performance
143 counter available on the system.
145 For now, the only calibration implemented is that of the kernel function
146 instrumentation (kretprobes).
148 * Calibrate kernel function instrumentation
150 Let's use an example to show this calibration. We use an i7 processor with 4
151 general-purpose PMU registers. This information is available by issuing dmesg,
152 looking for "generic registers".
154 This sequence of commands will gather a trace executing a kretprobe hooked on
155 an empty function, gathering PMU counters LLC (Last Level Cache) misses
156 information (see lttng add-context \-\-help to see the list of available PMU
160 # lttng create calibrate-function
161 # lttng enable-event calibrate \-\-kernel \\
162 \-\-function lttng_calibrate_kretprobe
163 # lttng add-context \-\-kernel \-t perf:LLC-load-misses \\
164 \-t perf:LLC-store-misses \\
165 \-t perf:LLC-prefetch-misses
167 # for a in $(seq 1 10); do \\
168 lttng calibrate \-\-kernel \-\-function;
171 # babeltrace $(ls \-1drt ~/lttng-traces/calibrate-function-* \\
175 The output from babeltrace can be saved to a text file and opened in a
176 spreadsheet (e.g. oocalc) to focus on the per-PMU counter delta between
177 consecutive "calibrate_entry" and "calibrate_return" events. Note that these
178 counters are per-CPU, so scheduling events would need to be present to account
179 for migration between CPU. Therefore, for calibration purposes, only events
180 staying on the same CPU must be considered.
182 The average result, for the i7, on 10 samples:
186 perf_LLC_load_misses: 5.0 0.577
187 perf_LLC_store_misses: 1.6 0.516
188 perf_LLC_prefetch_misses: 9.0 14.742
191 As we can notice, the load and store misses are relatively stable across runs
192 (their standard deviation is relatively low) compared to the prefetch misses.
193 We can conclude from this information that LLC load and store misses can be
194 accounted for quite precisely, but prefetches within a function seems to behave
195 too erratically (not much causality link between the code executed and the CPU
196 prefetch activity) to be accounted for.
202 Show summary of possible options and commands.
204 .BR "\-k, \-\-kernel"
205 Apply for the kernel tracer
207 .BR "\-u, \-\-userspace"
208 Apply for the user-space tracer
211 Dynamic function entry/return probe (default)
216 \fBcreate\fP [NAME] [OPTIONS]
218 Create tracing session.
220 A tracing session contains channel(s) which contains event(s). It is domain
221 agnostic, meaning that channels and events can be enabled for the
222 user-space tracer and/or the kernel tracer. It acts like a container
223 aggregating multiple tracing sources.
225 On creation, a \fB.lttngrc\fP file is created in your $HOME directory
226 containing the current session name. If NAME is omitted, a session name is
227 automatically created having this form: 'auto-yyyymmdd-hhmmss'.
229 If no \fB\-o, \-\-output\fP is specified, the traces will be written in
232 The $HOME environment variable can be overridden by defining the environment
233 variable LTTNG_HOME. This is useful when the user running the commands has
234 a non-writeable home directory.
240 Show summary of possible options and commands.
242 .BR "\-\-list-options"
243 Simple listing of options
245 .BR "\-o, \-\-output PATH"
246 Specify output path for traces
249 Traces will not be output
252 Set the session in snapshot mode. Created in no-output mode and uses the
253 URL, if one is specified, as the default snapshot output. Every channel will be set
254 in overwrite mode and with mmap output (splice not supported).
257 Set the session exclusively in live mode. The paremeter is the delay in micro
258 seconds before the data is flushed and streamed. The live mode allows you to
259 stream the trace and view it while it's being recorded by any tracer. For that,
260 you need a lttng-relayd and this session requires a network URL (\-U or
263 To read a live session, you can use babeltrace(1) or the live streaming
264 protocol in doc/live-reading-protocol.txt. Here is an example:
267 $ lttng-relayd -o /tmp/lttng
268 $ lttng create --live 200000 -U net://localhost
269 $ lttng enable-event -a --userspace
273 After the start, you'll be able to read the events while they are being
274 recorded in /tmp/lttng.
277 .BR "\-U, \-\-set-url=URL"
278 Set URL for the consumer output destination. It is persistent for the
279 session lifetime. Redo the command to change it. This will set both data
280 and control URL for network.
282 .BR "\-C, \-\-ctrl-url=URL"
283 Set control path URL. (Must use -D also)
285 .BR "\-D, \-\-data-url=URL"
286 Set data path URL. (Must use -C also)
288 Using these options, each API call can be controlled individually. For
289 instance, \-C does not enable the consumer automatically. You'll need the \-e
294 proto://[HOST|IP][:PORT1[:PORT2]][/TRACE_PATH]
296 Supported protocols are (proto):
299 Local filesystem full path.
303 This will use the default network transport layer which is TCP for both
304 control (PORT1) and data port (PORT2). The default ports are
305 respectively 5342 and 5343. Note that net[6]:// is not yet supported.
309 Can only be used with -C and -D together
311 NOTE: IPv6 address MUST be enclosed in brackets '[]' (rfc2732)
316 # lttng create -U net://192.168.1.42
318 Uses TCP and default ports for the given destination.
321 # lttng create -U net6://[fe80::f66d:4ff:fe53:d220]
323 Uses TCP, default ports and IPv6.
326 # lttng create s1 -U net://myhost.com:3229
328 Create session s1 and set its consumer to myhost.com on port 3229 for control.
333 \fBdestroy\fP [NAME] [OPTIONS]
335 Teardown tracing session
337 Free memory on the session daemon and tracer side. It's gone!
339 If NAME is omitted, the session name is taken from the .lttngrc file.
345 Show summary of possible options and commands.
350 .BR "\-\-list-options"
351 Simple listing of options
356 \fBenable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
358 Enable tracing channel
360 To enable an event, you must enable both the event and the channel that
363 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
366 Exactly one of \-k or -u must be specified.
368 It is important to note that if a certain type of buffers is used, the session
369 will be set with that type and all other subsequent channel needs to have the
372 Note that once the session has been started and enabled on the tracer side,
373 it's not possible anymore to enable a new channel for that session.
381 .BR "\-\-list-options"
382 Simple listing of options
384 .BR "\-s, \-\-session NAME"
385 Apply on session name
387 .BR "\-k, \-\-kernel"
388 Apply to the kernel tracer
390 .BR "\-u, \-\-userspace"
391 Apply to the user-space tracer
394 Discard event when subbuffers are full (default)
397 Flight recorder mode : overwrites events when subbuffers are full
399 .BR "\-\-subbuf-size SIZE"
400 Subbuffer size in bytes {+k,+M,+G}.
401 (default UST uid: 131072, UST pid: 4096, kernel: 262144, metadata: 4096)
402 Rounded up to the next power of 2.
404 The minimum subbuffer size, for each tracer, is the max value between
405 the default above and the system page size. You can issue this command
406 to get the current page size on your system: \fB$ getconf PAGE_SIZE\fP
408 .BR "\-\-num-subbuf NUM"
409 Number of subbuffers. (default UST uid: 4, UST pid: 4, kernel: 4,
410 metadata: 2) Rounded up to the next power of 2.
412 .BR "\-\-switch-timer USEC"
413 Switch subbuffer timer interval in µsec.
414 (default UST uid: 0, UST pid: 0, kernel: 0, metadata: 0)
416 .BR "\-\-read-timer USEC"
417 Read timer interval in µsec.
418 (default UST uid: 0, UST pid: 0, kernel: 200000, metadata: 0)
420 .BR "\-\-output TYPE"
421 Channel output type. Possible values: mmap, splice
422 (default UST uid: mmap, UST pid: mmap, kernel: splice, metadata: mmap)
424 .BR "\-\-buffers-uid"
425 Use per UID buffer (\-u only). Buffers are shared between applications
426 that have the same UID.
428 .BR "\-\-buffers-pid"
429 Use per PID buffer (\-u only). Each application has its own buffers.
431 .BR "\-\-buffers-global"
432 Use shared buffer for the whole system (\-k only)
434 .BR "\-C, \-\-tracefile-size SIZE"
435 Maximum size of each tracefile within a stream (in bytes).
436 0 means unlimited. (default: 0)
438 .BR "\-W, \-\-tracefile-count COUNT"
439 Used in conjunction with \-C option, this will limit the number of files
440 created to the specified count. 0 means unlimited. (default: 0)
445 $ lttng enable-channel -k -C 4096 -W 32 chan1
447 For each stream, the maximum size of each trace file will be 4096 bytes and
448 there will be a maximum of 32 different files. The file count is appended after
449 the stream number as seen in the following example. The last trace file is
450 smaller than 4096 since it was not completely filled.
453 ~/lttng-traces/[...]/chan1_0_0 (4096)
454 ~/lttng-traces/[...]/chan1_0_1 (4096)
455 ~/lttng-traces/[...]/chan1_0_2 (3245)
456 ~/lttng-traces/[...]/chan1_1_0 (4096)
461 $ lttng enable-channel -k -C 4096
463 This will create trace files of 4096 bytes and will create new ones as long as
464 there is data available.
469 \fBenable-event\fP NAME[,NAME2,...] [-k|-u] [OPTIONS]
473 A tracing event is always assigned to a channel. If \fB\-c, \-\-channel\fP is
474 omitted, a default channel named '\fBchannel0\fP' is created and the event is
475 added to it. If \fB\-c, \-\-channel\fP is omitted, but a non-default
476 channel already exists within the session, an error is returned. For the
477 user-space tracer, using \fB\-a, \-\-all\fP is the same as using the
480 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
487 Show summary of possible options and commands.
489 .BR "\-\-list-options"
490 Simple listing of options
492 .BR "\-s, \-\-session NAME"
493 Apply on session name
495 .BR "\-c, \-\-channel NAME"
496 Apply on channel name
499 Enable all tracepoints and syscalls. This actually enables a single
502 .BR "\-k, \-\-kernel"
503 Apply for the kernel tracer
505 .BR "\-u, \-\-userspace"
506 Apply for the user-space tracer
509 Apply for Java application using Java Util Logging interface (JUL)
512 Tracepoint event (default). Userspace tracer supports wildcards at the end
513 of string. Don't forget to quote to deal with bash expansion.
520 .BR "\-\-loglevel NAME"
521 Tracepoint loglevel range from 0 to loglevel. Listed in the help (\-h).
522 For the JUL domain, the loglevel ranges are detailed with the \-\-help
523 option thus starting from SEVERE to FINEST.
525 .BR "\-\-loglevel-only NAME"
526 Tracepoint loglevel (only this loglevel).
527 The loglevel or loglevel-only options should be combined with a
528 tracepoint name or tracepoint wildcard.
530 .BR "\-\-probe (addr | symbol | symbol+offset)"
531 Dynamic probe. Addr and offset can be octal (0NNN...), decimal (NNN...)
532 or hexadecimal (0xNNN...)
534 .BR "\-\-function (addr | symbol | symbol+offset)"
535 Dynamic function entry/return probe. Addr and offset can be octal
536 (0NNN...), decimal (NNN...) or hexadecimal (0xNNN...)
539 System call event. Enabling syscalls tracing (kernel tracer), you will
540 not be able to disable them with disable-event. This is a known
541 limitation. You can disable the entire channel to do the trick.
543 .BR "\-\-filter 'expression'"
544 Set a filter on a newly enabled event. Filter expression on event
545 fields and context. The event will be recorded if the filter's
546 expression evaluates to TRUE. Only specify on first activation of a
547 given event within a session.
548 Specifying a filter is only allowed when enabling events within a session before
549 tracing is started. If the filter fails to link with the event
550 within the traced domain, the event will be discarded.
551 Filtering is currently only implemented for the user-space tracer.
556 'intfield > 500 && intfield < 503'
557 '(strfield == "test" || intfield != 10) && intfield > 33'
558 'doublefield > 1.1 && intfield < 5.3'
561 Wildcards are allowed at the end of strings:
563 In string literals, the escape character is a '\\'. Use '\\*' for
564 the '*' character, and '\\\\' for the '\\' character sequence. Wildcard
565 matches any sequence of characters, including an empty sub-string
566 (matches 0 or more characters).
568 Context information can be used for filtering. The examples below shows
569 usage of context filtering on the process name (using a wildcard), process ID
570 range, and unique thread ID. The process and thread IDs of
571 running applications can be found under columns "PID" and "LWP" of the
575 '$ctx.procname == "demo*"'
576 '$ctx.vpid >= 4433 && $ctx.vpid < 4455'
581 .BR "\-x, \-\-exclude LIST"
582 Add exclusions to UST tracepoints:
583 Events that match any of the items in the comma-separated LIST are not
584 enabled, even if they match a wildcard definition of the event.
586 This option is also applicable with the \fB\-a, \-\-all\fP option,
587 in which case all UST tracepoints are enabled except the ones whose
588 names match any of the items in LIST.
593 \fBdisable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
595 Disable tracing channel
597 Disabling a channel disables the tracing of all of the channel's events. A channel
598 can be reenabled by calling \fBlttng enable-channel NAME\fP again.
600 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
607 Show summary of possible options and commands.
609 .BR "\-\-list-options"
610 Simple listing of options
612 .BR "\-s, \-\-session NAME"
613 Apply on session name
615 .BR "\-k, \-\-kernel"
616 Apply for the kernel tracer
618 .BR "\-u, \-\-userspace"
619 Apply for the user-space tracer
624 \fBdisable-event\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
626 Disable tracing event
628 The event, once disabled, can be re-enabled by calling \fBlttng enable-event
631 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
634 If \fB\-c, \-\-channel\fP is omitted, the default channel name is used.
635 If \fB\-c, \-\-channel\fP is omitted, but a non-default channel already
636 exists within the session, an error is returned.
642 Show summary of possible options and commands.
644 .BR "\-\-list-options"
645 Simple listing of options
647 .BR "\-s, \-\-session NAME"
648 Apply on session name
650 .BR "\-c, \-\-channel NAME"
651 Apply on channel name
653 .BR "\-a, \-\-all-events"
654 Disable all events. This does NOT disable "*" but rather every known
655 events of the session.
657 .BR "\-k, \-\-kernel"
658 Apply for the kernel tracer
660 .BR "\-u, \-\-userspace"
661 Apply for the user-space tracer
664 Apply for Java application using Java Util Logging interface (JUL)
669 \fBlist\fP [OPTIONS] [SESSION [SESSION OPTIONS]]
671 List tracing session information.
673 With no arguments, it will list available tracing session(s).
675 With the session name, it will display the details of the session including
676 the trace file path, the associated channels and their state (activated
677 and deactivated), the activated events and more.
679 With \-k alone, it will list all available kernel events (except the system
681 With \-j alone, the available JUL event from registered application will be
682 list. The event corresponds to the Logger name in the Java JUL application.
683 With \-u alone, it will list all available user-space events from registered
684 applications. Here is an example of 'lttng list \-u':
687 PID: 7448 - Name: /tmp/lttng-ust/tests/hello/.libs/lt-hello
688 ust_tests_hello:tptest_sighandler (type: tracepoint)
689 ust_tests_hello:tptest (type: tracepoint)
692 You can now enable any event listed by using the name :
693 \fBust_tests_hello:tptest\fP.
699 Show summary of possible options and commands.
701 .BR "\-\-list-options"
702 Simple listing of options
704 .BR "\-k, \-\-kernel"
707 .BR "\-u, \-\-userspace"
708 Select user-space domain.
711 Apply for Java application using JUL
713 .BR "\-f, \-\-fields"
720 .BR "\-c, \-\-channel NAME"
721 List details of a channel
723 .BR "\-d, \-\-domain"
724 List available domain(s)
729 \fBset-session\fP NAME [OPTIONS]
731 Set current session name
733 Will change the session name in the .lttngrc file.
739 Show summary of possible options and commands.
741 .BR "\-\-list-options"
742 Simple listing of options
747 \fBsnapshot\fP [OPTIONS] ACTION
749 Snapshot command for LTTng session.
755 Show summary of possible options and commands.
757 .BR "\-\-list-options"
758 Simple listing of options
764 \fBadd-output\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] <URL> | -C <URL> -D <URL>
766 Setup and add an snapshot output for a session. Output are the destination
767 where the snapshot will be sent. Only one output is permitted. To change it,
768 you'll need to delete it and add back the new one.
771 \fBdel-output\fP ID | NAME [-s <NAME>]
773 Delete an output for a session using the ID. You can either specify the
774 output's ID that can be found with list-output or the name.
777 \fBlist-output\fP [-s <NAME>]
779 List the output of a session. Attributes of the output are printed.
782 \fBrecord\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] [<URL> | -C <URL> -D <URL>]
784 Snapshot a session's buffer(s) for all domains. If an URL is specified, it is
785 used instead of a previously added output. Specifying only a name or/and a max
786 size will override the current output values. For instance, you can record a
787 snapshot with a custom maximum size or with a different name.
790 $ lttng snapshot add-output -n mysnapshot file:///data/snapshot
792 $ lttng snapshot record -n new_name_snapshot
795 The above will create a snapshot in /data/snapshot/new_name_snapshot* directory
796 rather then in mysnapshot*/
799 .B DETAILED ACTION OPTIONS
802 .BR "\-s, \-\-session NAME"
803 Apply to session name.
805 .BR "\-n, \-\-name NAME"
806 Name of the snapshot's output.
808 .BR "\-m, \-\-max-size SIZE"
809 Maximum size in bytes of the snapshot. The maxium size does not include the
810 metadata file. Human readable format is accepted: {+k,+M,+G}. For instance,
813 .BR "\-C, \-\-ctrl-url URL"
814 Set control path URL. (Must use -D also)
816 .BR "\-D, \-\-data-url URL"
817 Set data path URL. (Must use -C also)
822 \fBstart\fP [NAME] [OPTIONS]
826 It will start tracing for all tracers for a specific tracing session.
827 If NAME is omitted, the session name is taken from the .lttngrc file.
833 Show summary of possible options and commands.
835 .BR "\-\-list-options"
836 Simple listing of options
841 \fBstop\fP [NAME] [OPTIONS]
845 It will stop tracing for all tracers for a specific tracing session. Before
846 returning, the command checks for data availability meaning that it will wait
847 until the trace is readable for the session. Use \-\-no-wait to avoid this
850 If NAME is omitted, the session name is taken from the .lttngrc file.
856 Show summary of possible options and commands.
858 .BR "\-\-list-options"
859 Simple listing of options
861 Don't wait for data availability.
868 Show version information
874 Show summary of possible options and commands.
876 .BR "\-\-list-options"
877 Simple listing of options
882 \fBview\fP [SESSION_NAME] [OPTIONS]
884 View traces of a tracing session. By default, the babeltrace viewer
885 will be used for text viewing. If SESSION_NAME is omitted, the session
886 name is taken from the .lttngrc file.
894 .BR "\-\-list-options"
895 Simple listing of options
897 .BR "\-t, \-\-trace-path PATH"
898 Trace directory path for the viewer
900 .BR "\-e, \-\-viewer CMD"
901 Specify viewer and/or options to use This will completely override the
902 default viewers so please make sure to specify the full command. The
903 trace directory path of the session will be appended at the end to the
909 This section explains the JUL domain (\-j, \-\-jul) where JUL stands for Java
910 Util Logging. You can use that feature by using the \fBliblttng-ust-jul.so\fP
911 from the lttng-ust(3) project.
913 The LTTng Java Agent uses JNI to link the UST tracer to the Java application
914 that uses the agent. Thus, it behaves similarly to the UST domain (\-u). When
915 enabling events with the JUL domain, you enable a Logger name that will then be
916 mapped to a default UST tracepoint called \fBlttng_jul:jul_event\fP in the
917 \fBlttng_jul_channel\fP. Using the lttng-ctl API, any JUL events must use the
918 tracepoint event type (same as \-\-tracepoint).
920 Because of the default immutable channel (\fBlttng_jul_channel\fP), the
921 \fBenable-channel\fP command CAN NOT be used with the JUL domain thus not
922 having any \-j option.
924 For JUL event, loglevels are supported with the JUL ABI values. Use \fBlttng
925 enable-event \-h\fP to list them. Wildcards are NOT supported except the "*"
926 meaning all events (same as \-a).
928 Exactly like the UST domain, if the Java application has the same UID as you,
929 you can trace it. Same goes for the tracing group accessing root applications.
931 Finally, you can list every Logger name that are available from JUL registered
932 applications to the session daemon by using \fBlttng list \-j\fP.
934 Here is an example on how to use this domain.
939 $ lttng create aSession
940 $ lttng enable-event -s aSession -j MyCustomLoggerName
944 More information can be found in the lttng-ust documentation, see
945 java-util-logging.txt
950 On success 0 is returned and a positive value on error. Value of 1 means a command
951 error, 2 an undefined command, 3 a fatal error and 4 a command warning meaning that
952 something went wrong during the command.
954 Any other value above 10, please refer to
955 .BR "<lttng/lttng-error.h>"
956 for a detailed list or use lttng_strerror() to get a human readable string of
960 .SH "ENVIRONMENT VARIABLES"
963 Note that all command line options override environment variables.
967 .IP "LTTNG_SESSIOND_PATH"
968 Allows one to specify the full session daemon binary path to lttng command line
969 tool. You can also use \-\-sessiond-path option having the same effect.
975 .BR lttng-sessiond(8),
981 If you encounter any issues or usability problem, please report it on our
982 mailing list <lttng-dev@lists.lttng.org> to help improve this project or
983 at https://bugs.lttng.org which is a bugtracker.
989 lttng is distributed under the GNU General Public License version 2. See the file
992 A Web site is available at http://lttng.org for more information on the LTTng
995 You can also find our git tree at http://git.lttng.org.
997 Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
999 You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
1004 Thanks to Yannick Brosseau without whom this project would never have been so
1005 lean and mean! Also thanks to the Ericsson teams working on tracing which
1006 helped us greatly with detailed bug reports and unusual test cases.
1008 Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
1009 maintainer) and Jon Bernard for our Debian packages.
1011 Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
1012 Montreal for the LTTng journey.
1017 lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
1018 David Goulet. More people have since contributed to it. It is currently
1019 maintained by David Goulet <dgoulet@efficios.com>.