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