Man page fixes: missing --version option and typo
[lttng-tools.git] / doc / man / lttng.1
1 .TH "LTTNG" "1" "May 13th, 2014" "" ""
2
3 .SH "NAME"
4 lttng \(em LTTng 2.x tracer control command line tool
5
6 .SH "SYNOPSIS"
7
8 .PP
9 lttng [OPTIONS] <COMMAND>
10 .SH "DESCRIPTION"
11
12 .PP
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.
17
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
21 package.
22
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.
28
29 We introduce the notion of \fBtracing domains\fP which is essentially a type of
30 tracer (kernel, user space, JUL, LOG4J or Python for now). In the future, we
31 could see more tracer like for instance an hypervisor. For some commands,
32 you'll need to specify on which domain the command operates (\-u, \-k, \-l, \-j
33 or \-p). For instance, the kernel domain must be specified when enabling a
34 kernel event.
35
36 In order to trace the kernel, the session daemon needs to be running as root.
37 LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is
38 in that group can interact with the root session daemon and thus trace the
39 kernel. Session daemons can co-exist, meaning that you can have a session daemon
40 running as Alice that can be used to trace her applications along side with a
41 root daemon or even a Bob daemon. We highly recommend starting the session
42 daemon at boot time for stable and long term tracing.
43
44 Each user-space application instrumented with lttng-ust(3) will automatically
45 register with the root session daemon and its user session daemon. This allows
46 each daemon to list the available traceable applications and tracepoints at any
47 given moment (See the \fBlist\fP command).
48 .SH "OPTIONS"
49
50 .PP
51 This program follows the usual GNU command line syntax with long options starting with
52 two dashes. Below is a summary of the available options.
53 .PP
54
55 .TP
56 .BR "\-h, \-\-help"
57 Show summary of possible options and commands.
58 .TP
59 .BR "\-V, \-\-version"
60 Show version.
61 .TP
62 .BR "\-v, \-\-verbose"
63 Increase verbosity.
64 Three levels of verbosity are available which are triggered by putting additional v to
65 the option (\-vv or \-vvv)
66 .TP
67 .BR "\-q, \-\-quiet"
68 Suppress all messages (even errors).
69 .TP
70 .BR "\-g, \-\-group NAME"
71 Set unix tracing group name. (default: tracing)
72 .TP
73 .BR "\-n, \-\-no-sessiond"
74 Don't automatically spawn a session daemon.
75 .TP
76 .BR "\-\-sessiond\-path PATH"
77 Set session daemon full binary path.
78 .TP
79 .BR "\-\-list\-options"
80 Simple listing of lttng options.
81 .TP
82 .BR "\-\-list\-commands"
83 Simple listing of lttng commands.
84 .TP
85 .BR "\-m, \-\-mi TYPE
86 Machine interface
87
88 TYPE supported: XML
89
90 Machine interface (MI) mode converts the traditional pretty printing to a
91 machine output syntax. MI mode provides a format change-resistant way to access
92 information generated via the lttng command line.
93
94 When using MI mode, the data is printed on \fBstdout\fP. Error and warning are
95 printed on \fBstderr\fP with the pretty print default format.
96
97 If any errors occur during the execution of a command, the return value of the
98 command will be different than zero. In this case, lttng does NOT guarantee the
99 syntax and data validity of the generated MI output.
100
101 For XML output type, a schema definition (XSD) file used for validation can be
102 found under src/common/mi_lttng.xsd
103
104 .SH "COMMANDS"
105
106 .PP
107 \fBadd-context\fP [OPTIONS]
108 .RS
109 Add context to event(s) and/or channel(s).
110
111 A context is basically extra information appended to a channel. For instance,
112 you could ask the tracer to add the PID information for all events in a
113 channel. You can also add performance monitoring unit counters (perf PMU) using
114 the perf kernel API.
115
116 For example, this command will add the context information 'prio' and two per-CPU
117 perf counters (hardware branch misses and cache misses), to all events in the trace
118 data output:
119
120 .nf
121 # lttng add-context \-k \-t prio \-t perf:cpu:branch-misses \\
122 \-t perf:cpu:cache-misses
123 .fi
124
125 Please take a look at the help (\-h/\-\-help) for a detailed list of available
126 contexts.
127
128 Perf counters are available as per-CPU ("perf:cpu:...") and per-thread
129 ("perf:thread:...") counters. Currently, per-CPU counters can only be
130 used with the kernel tracing domain, and per-thread counters can only be
131 used with the UST tracing domain.
132
133 If no channel is given (\-c), the context is added to all channels that were
134 already enabled. If the session has no channel, a default channel is created.
135 Otherwise the context will be added only to the given channel (\-c).
136
137 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
138 file.
139
140 .B OPTIONS:
141
142 .TP
143 .BR "\-h, \-\-help"
144 Show summary of possible options and commands.
145 .TP
146 .BR "\-s, \-\-session NAME"
147 Apply on session name.
148 .TP
149 .BR "\-c, \-\-channel NAME"
150 Apply on channel name.
151 .TP
152 .BR "\-k, \-\-kernel"
153 Apply for the kernel tracer
154 .TP
155 .BR "\-u, \-\-userspace"
156 Apply for the user-space tracer
157 .TP
158 .BR "\-t, \-\-type TYPE"
159 Context type. You can repeat this option on the command line. Please
160 use "lttng add-context \-h" to list all available types.
161 .RE
162 .PP
163
164 .PP
165 \fBcalibrate\fP [OPTIONS]
166 .RS
167 Quantify LTTng overhead
168
169 The LTTng calibrate command can be used to find out the combined average
170 overhead of the LTTng tracer and the instrumentation mechanisms used. This
171 overhead can be calibrated in terms of time or using any of the PMU performance
172 counter available on the system.
173
174 For now, the only calibration implemented is that of the kernel function
175 instrumentation (kretprobes).
176
177 * Calibrate kernel function instrumentation
178
179 Let's use an example to show this calibration. We use an i7 processor with 4
180 general-purpose PMU registers. This information is available by issuing dmesg,
181 looking for "generic registers".
182
183 This sequence of commands will gather a trace executing a kretprobe hooked on
184 an empty function, gathering PMU counters LLC (Last Level Cache) misses
185 information (see lttng add-context \-\-help to see the list of available PMU
186 counters).
187
188 .nf
189 # lttng create calibrate-function
190 # lttng enable-event calibrate \-\-kernel \\
191 \-\-function lttng_calibrate_kretprobe
192 # lttng add-context \-\-kernel \-t perf:cpu:LLC-load-misses \\
193 \-t perf:cpu:LLC-store-misses \\
194 \-t perf:cpu:LLC-prefetch-misses
195 # lttng start
196 # for a in $(seq 1 10); do \\
197 lttng calibrate \-\-kernel \-\-function;
198 done
199 # lttng destroy
200 # babeltrace $(ls \-1drt ~/lttng-traces/calibrate-function-* \\
201 | tail \-n 1)
202 .fi
203
204 The output from babeltrace can be saved to a text file and opened in a
205 spreadsheet (e.g. oocalc) to focus on the per-PMU counter delta between
206 consecutive "calibrate_entry" and "calibrate_return" events. Note that these
207 counters are per-CPU, so scheduling events would need to be present to account
208 for migration between CPU. Therefore, for calibration purposes, only events
209 staying on the same CPU must be considered.
210
211 The average result, for the i7, on 10 samples:
212
213 .nf
214 Average Std.Dev.
215 perf_LLC_load_misses: 5.0 0.577
216 perf_LLC_store_misses: 1.6 0.516
217 perf_LLC_prefetch_misses: 9.0 14.742
218 .fi
219
220 As we can notice, the load and store misses are relatively stable across runs
221 (their standard deviation is relatively low) compared to the prefetch misses.
222 We can conclude from this information that LLC load and store misses can be
223 accounted for quite precisely, but prefetches within a function seems to behave
224 too erratically (not much causality link between the code executed and the CPU
225 prefetch activity) to be accounted for.
226
227 .B OPTIONS:
228
229 .TP
230 .BR "\-h, \-\-help"
231 Show summary of possible options and commands.
232 .TP
233 .BR "\-k, \-\-kernel"
234 Apply for the kernel tracer
235 .TP
236 .BR "\-u, \-\-userspace"
237 Apply for the user-space tracer
238 .TP
239 .BR "\-\-function"
240 Dynamic function entry/return probe (default)
241 .RE
242 .PP
243
244 .PP
245 \fBcreate\fP [NAME] [OPTIONS]
246 .RS
247 Create tracing session.
248
249 A tracing session contains channel(s) which contains event(s). It is domain
250 agnostic, meaning that channels and events can be enabled for the
251 user-space tracer and/or the kernel tracer. It acts like a container
252 aggregating multiple tracing sources.
253
254 On creation, a \fB.lttngrc\fP file is created in your $HOME directory
255 containing the current session name. If NAME is omitted, a session name is
256 automatically created having this form: 'auto-yyyymmdd-hhmmss'.
257
258 If no \fB\-o, \-\-output\fP is specified, the traces will be written in
259 $HOME/lttng-traces.
260
261 The $HOME environment variable can be overridden by defining the environment
262 variable LTTNG_HOME. This is useful when the user running the commands has
263 a non-writeable home directory.
264
265 The session name MUST NOT contain the character '/'.
266
267 .B OPTIONS:
268
269 .TP
270 .BR "\-h, \-\-help"
271 Show summary of possible options and commands.
272 .TP
273 .BR "\-\-list-options"
274 Simple listing of options
275 .TP
276 .BR "\-o, \-\-output PATH"
277 Specify output path for traces
278 .TP
279 .BR "\-\-no-output"
280 Traces will not be output
281 .TP
282 .BR "\-\-snapshot"
283 Set the session in snapshot mode. Created in no-output mode and uses the
284 URL, if one is specified, as the default snapshot output. Every channel will be set
285 in overwrite mode and with mmap output (splice not supported).
286 .TP
287 .BR "\-\-live [USEC]"
288 Set the session exclusively in live mode. The parameter is the delay in micro
289 seconds before the data is flushed and streamed. The live mode allows you to
290 stream the trace and view it while it's being recorded by any tracer. For that,
291 you need a lttng-relayd and this session requires a network URL (\-U or
292 \-C/\-D). If no USEC nor URL is provided, the default is to use a timer value
293 set to 1000000 and the network URL set to net://127.0.0.1.
294
295 To read a live session, you can use babeltrace(1) or the live streaming
296 protocol in doc/live-reading-protocol.txt. Here is an example:
297
298 .nf
299 $ lttng-relayd -o /tmp/lttng
300 $ lttng create --live 200000 -U net://localhost
301 $ lttng enable-event -a --userspace
302 $ lttng start
303 .fi
304
305 After the start, you'll be able to read the events while they are being
306 recorded in /tmp/lttng.
307
308 .TP
309 .BR "\-\-shm-path PATH"
310
311 Path where shared memory holding buffers should be created. Useful
312 when used with PRAMFS or other persistent memory filesystems to extract
313 trace data in the event of a crash requiring a reboot.
314
315 .TP
316 .BR "\-U, \-\-set-url=URL"
317 Set URL for the consumer output destination. It is persistent for the
318 session lifetime. Redo the command to change it. This will set both data
319 and control URL for network.
320 .TP
321 .BR "\-C, \-\-ctrl-url=URL"
322 Set control path URL. (Must use -D also)
323 .TP
324 .BR "\-D, \-\-data-url=URL"
325 Set data path URL. (Must use -C also)
326 .PP
327 Using these options, each API call can be controlled individually. For
328 instance, \-C does not enable the consumer automatically. You'll need the \-e
329 option for that.
330
331 .B URL FORMAT:
332
333 proto://[HOST|IP][:PORT1[:PORT2]][/TRACE_PATH]
334
335 Supported protocols are (proto):
336 .TP
337 .BR "file://..."
338 Local filesystem full path.
339
340 .TP
341 .BR "net://..."
342 This will use the default network transport layer which is TCP for both
343 control (PORT1) and data port (PORT2). The default ports are
344 respectively 5342 and 5343. Note that net[6]:// is not yet supported.
345
346 .TP
347 .BR "tcp[6]://..."
348 Can only be used with -C and -D together
349
350 NOTE: IPv6 address MUST be enclosed in brackets '[]' (rfc2732)
351
352 .B EXAMPLES:
353
354 .nf
355 # lttng create -U net://192.168.1.42
356 .fi
357 Uses TCP and default ports for the given destination.
358
359 .nf
360 # lttng create -U net6://[fe80::f66d:4ff:fe53:d220]
361 .fi
362 Uses TCP, default ports and IPv6.
363
364 .nf
365 # lttng create s1 -U net://myhost.com:3229
366 .fi
367 Create session s1 and set its consumer to myhost.com on port 3229 for control.
368 .RE
369 .PP
370
371 .PP
372 \fBdestroy\fP [NAME] [OPTIONS]
373 .RS
374 Teardown tracing session
375
376 Free memory on the session daemon and tracer side. It's gone!
377
378 If NAME is omitted, the session name is taken from the .lttngrc file.
379
380 .B OPTIONS:
381
382 .TP
383 .BR "\-h, \-\-help"
384 Show summary of possible options and commands.
385 .TP
386 .BR "\-a, \-\-all"
387 Destroy all sessions
388 .TP
389 .BR "\-\-list-options"
390 Simple listing of options
391 .RE
392 .PP
393
394 .PP
395 \fBenable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
396 .RS
397 Enable tracing channel
398
399 To enable an event, you must enable both the event and the channel that
400 contains it.
401
402 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
403 file.
404
405 Exactly one of \-k or -u must be specified.
406
407 It is important to note that if a certain type of buffers is used, the session
408 will be set with that type and all other subsequent channel needs to have the
409 same type.
410
411 Note that once the session has been started and enabled on the tracer side,
412 it's not possible anymore to enable a new channel for that session.
413
414 .B OPTIONS:
415
416 .TP
417 .BR "\-h, \-\-help"
418 Show this help
419 .TP
420 .BR "\-\-list-options"
421 Simple listing of options
422 .TP
423 .BR "\-s, \-\-session NAME"
424 Apply on session name
425 .TP
426 .BR "\-k, \-\-kernel"
427 Apply to the kernel tracer
428 .TP
429 .BR "\-u, \-\-userspace"
430 Apply to the user-space tracer
431 .TP
432 .BR "\-\-discard"
433 Discard event when subbuffers are full (default)
434 .TP
435 .BR "\-\-overwrite"
436 Flight recorder mode: overwrites events when subbuffers are full. The
437 number of subbuffer must be 2 or more.
438 .TP
439 .BR "\-\-subbuf-size SIZE"
440 Subbuffer size in bytes {+k,+M,+G}.
441 (default UST uid: 131072, UST pid: 4096, kernel: 262144, metadata: 4096)
442 Rounded up to the next power of 2.
443
444 The minimum subbuffer size, for each tracer, is the max value between
445 the default above and the system page size. You can issue this command
446 to get the current page size on your system: \fB$ getconf PAGE_SIZE\fP
447 .TP
448 .BR "\-\-num-subbuf NUM"
449 Number of subbuffers. (default UST uid: 4, UST pid: 4, kernel: 4,
450 metadata: 2) Rounded up to the next power of 2.
451 .TP
452 .BR "\-\-switch-timer USEC"
453 Switch subbuffer timer interval in µsec.
454 (default UST uid: 0, UST pid: 0, kernel: 0, metadata: 0)
455 .TP
456 .BR "\-\-read-timer USEC"
457 Read timer interval in µsec.
458 (default UST uid: 0, UST pid: 0, kernel: 200000, metadata: 0)
459 .TP
460 .BR "\-\-output TYPE"
461 Channel output type. Possible values: mmap, splice
462 (default UST uid: mmap, UST pid: mmap, kernel: splice, metadata: mmap)
463 .TP
464 .BR "\-\-buffers-uid"
465 Use per UID buffer (\-u only). Buffers are shared between applications
466 that have the same UID.
467 .TP
468 .BR "\-\-buffers-pid"
469 Use per PID buffer (\-u only). Each application has its own buffers.
470 .TP
471 .BR "\-\-buffers-global"
472 Use shared buffer for the whole system (\-k only)
473 .TP
474 .BR "\-C, \-\-tracefile-size SIZE"
475 Maximum size of each tracefile within a stream (in bytes).
476 0 means unlimited. (default: 0)
477 Note: traces generated with this option may inaccurately report
478 discarded events as of CTF 1.8.
479 .TP
480 .BR "\-W, \-\-tracefile-count COUNT"
481 Used in conjunction with \-C option, this will limit the number of files
482 created to the specified count. 0 means unlimited. (default: 0)
483
484 .B EXAMPLES:
485
486 .nf
487 $ lttng enable-channel -k -C 4096 -W 32 chan1
488 .fi
489 For each stream, the maximum size of each trace file will be 4096 bytes and
490 there will be a maximum of 32 different files. The file count is appended after
491 the stream number as seen in the following example. The last trace file is
492 smaller than 4096 since it was not completely filled.
493
494 .nf
495 ~/lttng-traces/[...]/chan1_0_0 (4096)
496 ~/lttng-traces/[...]/chan1_0_1 (4096)
497 ~/lttng-traces/[...]/chan1_0_2 (3245)
498 ~/lttng-traces/[...]/chan1_1_0 (4096)
499 ...
500 .fi
501
502 .nf
503 $ lttng enable-channel -k -C 4096
504 .fi
505 This will create trace files of 4096 bytes and will create new ones as long as
506 there is data available.
507 .RE
508 .PP
509
510 .PP
511 \fBenable-event\fP NAME[,NAME2,...] [-k|-u] [OPTIONS]
512 .RS
513 Enable tracing event
514
515 A tracing event is always assigned to a channel. If \fB\-c, \-\-channel\fP is
516 omitted, a default channel named '\fBchannel0\fP' is created and the event is
517 added to it. If \fB\-c, \-\-channel\fP is omitted, but a non-default
518 channel already exists within the session, an error is returned. For the
519 user-space tracer, using \fB\-a, \-\-all\fP is the same as using the
520 wildcard "*".
521
522 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
523 file.
524
525 .B OPTIONS:
526
527 .TP
528 .BR "\-h, \-\-help"
529 Show summary of possible options and commands.
530 .TP
531 .BR "\-\-list-options"
532 Simple listing of options
533 .TP
534 .BR "\-s, \-\-session NAME"
535 Apply on session name
536 .TP
537 .BR "\-c, \-\-channel NAME"
538 Apply on channel name
539 .TP
540 .BR "\-a, \-\-all"
541 Enable all tracepoints and syscalls. This actually enables a single
542 wildcard event "*".
543 .TP
544 .BR "\-k, \-\-kernel"
545 Apply for the kernel tracer
546 .TP
547 .BR "\-u, \-\-userspace"
548 Apply for the user-space tracer
549 .TP
550 .BR "\-j, \-\-jul"
551 Apply for Java application using Java Util Logging interface (JUL)
552 .TP
553 .BR "\-l, \-\-log4j"
554 Apply for Java application using LOG4J
555 .TP
556 .BR "\-p, \-\-python"
557 Apply for Python application using the logging module.
558 .TP
559 .BR "\-\-tracepoint"
560 Tracepoint event (default). Userspace tracer supports wildcards at the end
561 of string. Don't forget to quote to deal with bash expansion.
562 e.g.:
563 .nf
564 "*"
565 "app_component:na*"
566 .fi
567 .TP
568 .BR "\-\-loglevel NAME"
569 Tracepoint loglevel range from 0 to loglevel. Listed in the help (\-h).
570 For the JUL domain, the loglevel ranges are detailed with the \-\-help
571 option thus starting from SEVERE to FINEST.
572 For the LOG4J domain, loglevels range from FATAL to TRACE which are also
573 detailed in the help.
574 For the Python domain, loglevels range from CRITICAL to DEBUG which are
575 detailed in the help as well.
576 .TP
577 .BR "\-\-loglevel-only NAME"
578 Tracepoint loglevel (only this loglevel).
579 The loglevel or loglevel-only options should be combined with a
580 tracepoint name or tracepoint wildcard.
581 .TP
582 .BR "\-\-probe (addr | symbol | symbol+offset)"
583 Dynamic probe. Addr and offset can be octal (0NNN...), decimal (NNN...)
584 or hexadecimal (0xNNN...)
585 .TP
586 .BR "\-\-function (addr | symbol | symbol+offset)"
587 Dynamic function entry/return probe. Addr and offset can be octal
588 (0NNN...), decimal (NNN...) or hexadecimal (0xNNN...)
589 .TP
590 .BR "\-\-syscall"
591 System call event. Enabling syscalls tracing (kernel tracer), you will
592 not be able to disable them with disable-event. This is a known
593 limitation. You can disable the entire channel to do the trick. Also note
594 that per-syscall selection is not supported yet. Use with "-a" to enable
595 all syscalls.
596 .TP
597 .BR "\-\-filter 'expression'"
598 Set a filter on a newly enabled event. Filter expression on event
599 fields and context. The event will be recorded if the filter's
600 expression evaluates to TRUE. Only specify on first activation of a
601 given event within a session.
602 Specifying a filter is only allowed when enabling events within a session before
603 tracing is started. If the filter fails to link with the event
604 within the traced domain, the event will be discarded.
605 Filtering is currently only implemented for the user-space tracer.
606
607 Expression examples:
608
609 .nf
610 'intfield > 500 && intfield < 503'
611 '(strfield == "test" || intfield != 10) && intfield > 33'
612 'doublefield > 1.1 && intfield < 5.3'
613 .fi
614
615 Wildcards are allowed at the end of strings:
616 'seqfield1 == "te*"'
617 In string literals, the escape character is a '\\'. Use '\\*' for
618 the '*' character, and '\\\\' for the '\\' character sequence. Wildcard
619 matches any sequence of characters, including an empty sub-string
620 (matches 0 or more characters).
621
622 Context information can be used for filtering. The examples below shows
623 usage of context filtering on the process name (using a wildcard), process ID
624 range, and unique thread ID. The process and thread IDs of
625 running applications can be found under columns "PID" and "LWP" of the
626 "ps -eLf" command.
627
628 .nf
629 '$ctx.procname == "demo*"'
630 '$ctx.vpid >= 4433 && $ctx.vpid < 4455'
631 '$ctx.vtid == 1234'
632 .fi
633
634 Context information is available to all filters whether or not the add-context
635 command has been used to add it to the event's channel, as long as the context
636 field exists for that domain. For example, the filter examples given above will
637 never fail to link: no add-context is required for the event's channel.
638
639 .TP
640 .BR "\-x, \-\-exclude LIST"
641 Add exclusions to UST tracepoints:
642 Events that match any of the items in the comma-separated LIST are not
643 enabled, even if they match a wildcard definition of the event.
644
645 This option is also applicable with the \fB\-a, \-\-all\fP option,
646 in which case all UST tracepoints are enabled except the ones whose
647 names match any of the items in LIST.
648 .RE
649 .PP
650
651 .PP
652 \fBdisable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
653 .RS
654 Disable tracing channel
655
656 Disabling a channel disables the tracing of all of the channel's events. A channel
657 can be re-enabled by calling \fBlttng enable-channel NAME\fP again.
658
659 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
660 file.
661
662 .B OPTIONS:
663
664 .TP
665 .BR "\-h, \-\-help"
666 Show summary of possible options and commands.
667 .TP
668 .BR "\-\-list-options"
669 Simple listing of options
670 .TP
671 .BR "\-s, \-\-session NAME"
672 Apply on session name
673 .TP
674 .BR "\-k, \-\-kernel"
675 Apply for the kernel tracer
676 .TP
677 .BR "\-u, \-\-userspace"
678 Apply for the user-space tracer
679 .RE
680 .PP
681
682 .PP
683 \fBdisable-event\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
684 .RS
685 Disable tracing event
686
687 The event, once disabled, can be re-enabled by calling \fBlttng enable-event
688 NAME\fP again.
689
690 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
691 file.
692
693 If \fB\-c, \-\-channel\fP is omitted, the default channel name is used.
694 If \fB\-c, \-\-channel\fP is omitted, but a non-default channel already
695 exists within the session, an error is returned.
696
697 .B OPTIONS:
698
699 .TP
700 .BR "\-h, \-\-help"
701 Show summary of possible options and commands.
702 .TP
703 .BR "\-\-list-options"
704 Simple listing of options
705 .TP
706 .BR "\-s, \-\-session NAME"
707 Apply on session name
708 .TP
709 .BR "\-c, \-\-channel NAME"
710 Apply on channel name
711 .TP
712 .BR "\-a, \-\-all-events"
713 Disable all events. This does NOT disable "*" but rather every known
714 events of the session.
715 .TP
716 .BR "\-k, \-\-kernel"
717 Apply for the kernel tracer
718 .TP
719 .BR "\-u, \-\-userspace"
720 Apply for the user-space tracer
721 .TP
722 .BR "\-j, \-\-jul"
723 Apply for Java application using Java Util Logging interface (JUL)
724 .TP
725 .BR "\-l, \-\-log4j"
726 Apply for Java application using LOG4J
727 .TP
728 .BR "\-p, \-\-python"
729 Apply for Python application using the logging module.
730 .RE
731 .PP
732
733 .PP
734 \fBlist\fP [OPTIONS] [SESSION [SESSION OPTIONS]]
735 .RS
736 List tracing session information.
737
738 With no arguments, it will list available tracing session(s).
739
740 With the session name, it will display the details of the session including
741 the trace file path, the associated channels and their state (activated
742 and deactivated), the activated events and more.
743
744 With \-k alone, it will list all available kernel events (except the system
745 calls events).
746 With \-j alone, the available JUL event from registered application will be
747 list. The event corresponds to the Logger name in the Java JUL application.
748 With \-l alone, the available LOG4J event from registered application will be
749 list. The event corresponds to the Logger name in the Java LOG4J application.
750 With \-p alone, the available Python event from registered application will be
751 list. The event corresponds to the Logger name in the Python application.
752 With \-u alone, it will list all available user-space events from registered
753 applications. Here is an example of 'lttng list \-u':
754
755 .nf
756 PID: 7448 - Name: /tmp/lttng-ust/tests/hello/.libs/lt-hello
757 ust_tests_hello:tptest_sighandler (type: tracepoint)
758 ust_tests_hello:tptest (type: tracepoint)
759 .fi
760
761 You can now enable any event listed by using the name :
762 \fBust_tests_hello:tptest\fP.
763
764 .B OPTIONS:
765
766 .TP
767 .BR "\-h, \-\-help"
768 Show summary of possible options and commands.
769 .TP
770 .BR "\-\-list-options"
771 Simple listing of options
772 .TP
773 .BR "\-k, \-\-kernel"
774 Select kernel domain
775 .TP
776 .BR "\-u, \-\-userspace"
777 Select user-space domain.
778 .TP
779 .BR "\-j, \-\-jul"
780 Apply for Java application using JUL
781 .TP
782 .BR "\-l, \-\-log4j"
783 Apply for Java application using LOG4J
784 .TP
785 .BR "\-p, \-\-python"
786 Apply for Python application using the logging module.
787 .TP
788 .BR "\-f, \-\-fields"
789 List event fields
790
791 .PP
792 .B SESSION OPTIONS:
793
794 .TP
795 .BR "\-c, \-\-channel NAME"
796 List details of a channel
797 .TP
798 .BR "\-d, \-\-domain"
799 List available domain(s)
800 .RE
801 .PP
802
803 .PP
804 \fBload\fP [OPTIONS] [NAME]
805 .RS
806 Load tracing session configuration
807
808 If NAME is omitted, all session configurations found in both the user's session
809 configuration directory (default: ~/.lttng/sessions/) and the system session
810 configuration directory (default: /etc/lttng/sessions/) will be loaded. Note
811 that the sessions in the user directory are loaded first and then the system
812 wide directory are loaded.
813
814 .B OPTIONS:
815
816 .TP
817 .BR "\-h, \-\-help"
818 Show summary of possible options and commands.
819 .TP
820 .BR "\-a, \-\-all"
821 Load all session configurations (default).
822 .TP
823 .BR "\-i, \-\-input-path PATH"
824 Specify the input path for session configurations. This overrides the default
825 session configuration directory.
826 .TP
827 .BR "\-f, -\-force"
828 Overwrite current session configuration(s) if a session of the same name
829 already exists.
830 .RE
831 .PP
832
833 .PP
834 \fBsave\fP [OPTIONS] [SESSION]
835 .RS
836 Save tracing session configuration
837
838 If SESSION is omitted, all session configurations will be saved to individual
839 \fB.lttng\fP files under the user's session configuration directory (default:
840 ~/.lttng/sessions/). The default session configuration file naming scheme is
841 \fBSESSION.lttng\fP.
842
843 For instance, a user in the tracing group saving a session from a root session
844 daemon will save it in her/his user directory.
845
846 .B OPTIONS:
847
848 .TP
849 .BR "\-h, \-\-help"
850 Show summary of possible options and commands.
851 .TP
852 .BR "\-a, \-\-all"
853 Save all session configurations (default).
854 .TP
855 .BR "\-o, \-\-output-path PATH"
856 Specify the output path for saved sessions. This overrides the default session
857 configuration directory.
858 .TP
859 .BR "\-f, -\-force"
860 Overwrite session configuration file if session name clashes.
861 .RE
862 .PP
863
864 .PP
865 \fBset-session\fP NAME [OPTIONS]
866 .RS
867 Set current session name
868
869 Will change the session name in the .lttngrc file.
870
871 .B OPTIONS:
872
873 .TP
874 .BR "\-h, \-\-help"
875 Show summary of possible options and commands.
876 .TP
877 .BR "\-\-list-options"
878 Simple listing of options
879 .RE
880 .PP
881
882 .PP
883 \fBsnapshot\fP [OPTIONS] ACTION
884 .RS
885 Snapshot command for LTTng session.
886
887 .B OPTIONS:
888
889 .TP
890 .BR "\-h, \-\-help"
891 Show summary of possible options and commands.
892 .TP
893 .BR "\-\-list-options"
894 Simple listing of options
895
896 .PP
897 .B ACTION:
898
899 .TP
900 \fBadd-output\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] <URL> | -C <URL> -D <URL>
901
902 Setup and add a snapshot output for a session. Output is the destination
903 where the snapshot will be sent. Only one output is permitted. To change it,
904 you'll need to delete it and add back the new one.
905
906 .TP
907 \fBdel-output\fP ID | NAME [-s <NAME>]
908
909 Delete an output for a session using the output's ID. You can either specify the
910 output by name or use its ID as returned by the list-output command.
911
912 .TP
913 \fBlist-output\fP [-s <NAME>]
914
915 List the output of a session. Attributes of the output are printed.
916
917 .TP
918 \fBrecord\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] [<URL> | -C <URL> -D <URL>]
919
920 Snapshot a session's buffer(s) for all domains. If an URL is specified, it is
921 used instead of a previously added output. Specifying only a name or/and a max
922 size will override the current output values. For instance, you can record a
923 snapshot with a custom maximum size or with a different name.
924
925 .nf
926 $ lttng snapshot add-output -n mysnapshot file:///data/snapshot
927 [...]
928 $ lttng snapshot record -n new_name_snapshot
929 .fi
930
931 The above will create a snapshot in /data/snapshot/new_name_snapshot* directory
932 rather then in mysnapshot*/
933
934 .PP
935 .B DETAILED ACTION OPTIONS
936
937 .TP
938 .BR "\-s, \-\-session NAME"
939 Apply to session name.
940 .TP
941 .BR "\-n, \-\-name NAME"
942 Name of the snapshot's output.
943 .TP
944 .BR "\-m, \-\-max-size SIZE"
945 Maximum size in bytes of the snapshot. The maximum size does not include the
946 metadata file. Human readable format is accepted: {+k,+M,+G}. For instance,
947 \-\-max-size 5M
948 .TP
949 .BR "\-C, \-\-ctrl-url URL"
950 Set control path URL. (Must use -D also)
951 .TP
952 .BR "\-D, \-\-data-url URL"
953 Set data path URL. (Must use -C also)
954 .RE
955 .PP
956
957 .PP
958 \fBstart\fP [NAME] [OPTIONS]
959 .RS
960 Start tracing
961
962 It will start tracing for all tracers for a specific tracing session.
963 If NAME is omitted, the session name is taken from the .lttngrc file.
964
965 .B OPTIONS:
966
967 .TP
968 .BR "\-h, \-\-help"
969 Show summary of possible options and commands.
970 .TP
971 .BR "\-\-list-options"
972 Simple listing of options
973 .RE
974 .PP
975
976 .PP
977 \fBstop\fP [NAME] [OPTIONS]
978 .RS
979 Stop tracing
980
981 It will stop tracing for all tracers for a specific tracing session. Before
982 returning, the command checks for data availability meaning that it will wait
983 until the trace is readable for the session. Use \-\-no-wait to avoid this
984 behavior.
985
986 If NAME is omitted, the session name is taken from the .lttngrc file.
987
988 .B OPTIONS:
989
990 .TP
991 .BR "\-h, \-\-help"
992 Show summary of possible options and commands.
993 .TP
994 .BR "\-\-list-options"
995 Simple listing of options
996 .TP
997 .BR "\-\-no-wait"
998 Don't wait for data availability.
999 .RE
1000 .PP
1001
1002 .PP
1003 \fBversion\fP
1004 .RS
1005 Show version information
1006
1007 .B OPTIONS:
1008
1009 .TP
1010 .BR "\-h, \-\-help"
1011 Show summary of possible options and commands.
1012 .TP
1013 .BR "\-\-list-options"
1014 Simple listing of options
1015 .RE
1016 .PP
1017
1018 .PP
1019 \fBview\fP [SESSION_NAME] [OPTIONS]
1020 .RS
1021 View traces of a tracing session. By default, the babeltrace viewer
1022 will be used for text viewing. If SESSION_NAME is omitted, the session
1023 name is taken from the .lttngrc file.
1024
1025 .B OPTIONS:
1026
1027 .TP
1028 .BR "\-h, \-\-help"
1029 Show this help
1030 .TP
1031 .BR "\-\-list-options"
1032 Simple listing of options
1033 .TP
1034 .BR "\-t, \-\-trace-path PATH"
1035 Trace directory path for the viewer
1036 .TP
1037 .BR "\-e, \-\-viewer CMD"
1038 Specify viewer and/or options to use This will completely override the
1039 default viewers so please make sure to specify the full command. The
1040 trace directory path of the session will be appended at the end to the
1041 arguments
1042 .RE
1043 .PP
1044
1045 .SH "JUL/LOG4J DOMAIN"
1046
1047 This section explains the JUL and LOG4J domain where JUL stands for Java Util
1048 Logging. You can use these by using the \fBliblttng-ust-<domain>-jni.so\fP from
1049 the lttng-ust(3) project.
1050
1051 The LTTng Java Agent uses JNI to link the UST tracer to the Java application
1052 that uses the agent. Thus, it behaves similarly to the UST domain (\-u). When
1053 enabling events, you enable a Logger name that will then be mapped to a default
1054 UST tracepoint called \fBlttng_jul:<domain>_event\fP in the
1055 \fBlttng_<domain>_channel\fP. Using the lttng-ctl API, any JUL/LOG4J events
1056 must use the tracepoint event type (same as \-\-tracepoint).
1057
1058 Because of the default immutable channel, the \fBenable-channel\fP command CAN
1059 NOT be used with the JUL and LOG4J domain thus not having any options.
1060
1061 Also, loglevels are supported. Use \fBlttng enable-event \-h\fP to list them.
1062 Wildcards are NOT supported except the "*" meaning all events (same as \-a).
1063
1064 Exactly like the UST domain, if the Java application has the same UID as you,
1065 you can trace it. Same goes for the tracing group accessing root applications.
1066
1067 Finally, you can list every Logger name that are available from registered
1068 applications to the session daemon by using \fBlttng list \-j\fP or \fB\-l\fP.
1069
1070 Here is an example on how to use the JUL domain.
1071
1072 .nf
1073 $ lttng list -j
1074 [...]
1075 $ lttng create aSession
1076 $ lttng enable-event -s aSession -j MyCustomLoggerName
1077 $ lttng start
1078 .fi
1079
1080 More information can be found in the lttng-ust documentation, see
1081 java-util-logging.txt
1082 .PP
1083
1084 .SH "EXIT VALUES"
1085 .PP
1086 On success 0 is returned and a positive value on error. Value of 1 means a command
1087 error, 2 an undefined command, 3 a fatal error and 4 a command warning meaning that
1088 something went wrong during the command.
1089
1090 Any other value above 10, please refer to
1091 .BR "<lttng/lttng-error.h>"
1092 for a detailed list or use lttng_strerror() to get a human readable string of
1093 the error code.
1094 .PP
1095
1096 .SH "ENVIRONMENT VARIABLES"
1097
1098 .PP
1099 Note that all command line options override environment variables.
1100 .PP
1101
1102 .PP
1103 .IP "LTTNG_SESSIOND_PATH"
1104 Allows one to specify the full session daemon binary path to lttng command line
1105 tool. You can also use \-\-sessiond-path option having the same effect.
1106 .PP
1107
1108 .PP
1109 .IP "LTTNG_SESSION_CONFIG_XSD_PATH"
1110 Set the path in which the \fBsession.xsd\fP session configuration schema may be
1111 found.
1112 .PP
1113
1114 .SH "SEE ALSO"
1115 .BR babeltrace(1),
1116 .BR lttng-ust(3),
1117 .BR lttng-sessiond(8),
1118 .BR lttng-relayd(8),
1119
1120 .SH "BUGS"
1121
1122 .PP
1123 If you encounter any issues or usability problem, please report it on our
1124 mailing list <lttng-dev@lists.lttng.org> to help improve this project or
1125 at https://bugs.lttng.org which is a bug tracker.
1126 .PP
1127
1128 .SH "CREDITS"
1129
1130 .PP
1131 lttng is distributed under the GNU General Public License version 2. See the file
1132 COPYING for details.
1133 .PP
1134 A Web site is available at http://lttng.org for more information on the LTTng
1135 project.
1136 .PP
1137 You can also find our git tree at http://git.lttng.org.
1138 .PP
1139 Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
1140 .PP
1141 You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
1142 .PP
1143 .SH "THANKS"
1144
1145 .PP
1146 Thanks to Yannick Brosseau without whom this project would never have been so
1147 lean and mean! Also thanks to the Ericsson teams working on tracing which
1148 helped us greatly with detailed bug reports and unusual test cases.
1149
1150 Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
1151 maintainer) and Jon Bernard for our Debian packages.
1152
1153 Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
1154 Montreal for the LTTng journey.
1155 .PP
1156 .SH "AUTHORS"
1157
1158 .PP
1159 lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
1160 David Goulet. More people have since contributed to it. It is currently
1161 maintained by Jérémie Galarneau <jeremie.galarneau@efficios.com>.
1162 .PP
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