Manpage: other layout cleanups
[lttng-tools.git] / doc / man / lttng.1
1 .TH "LTTNG" "1" "July 18th, 2013" "" ""
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 It's tracers help tracking down performance issues and debugging 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 interactions with the tracer should
20 be done by this tool or by the liblttng-ctl provided with 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 or user space for now). In the future, we could see a third
31 tracer being for instance an hypervisor. For some commands, you'll need to
32 specify on which domain the command applies (-u or -k). For instance, enabling
33 a kernel event, you must specify the kernel domain to the command so we know
34 for which tracer this event is for.
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 to start the session
42 daemon at boot time for stable and long term tracing.
43
44 Every user-space applications instrumented with lttng-ust(3), will
45 automatically register to the session daemon. This feature gives you the
46 ability to list available traceable applications and tracepoints on a per user
47 basis. (See \fBlist\fP command).
48 .SH "OPTIONS"
49
50 .PP
51 This program follow 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, \-\-verbose"
60 Increase verbosity.
61 Three levels of verbosity are available which are triggered by putting additional v to
62 the option (\-vv or \-vvv)
63 .TP
64 .BR "\-q, \-\-quiet"
65 Suppress all messages (even errors).
66 .TP
67 .BR "\-g, \-\-group NAME"
68 Set unix tracing group name. (default: tracing)
69 .TP
70 .BR "\-n, \-\-no-sessiond"
71 Don't automatically spawn a session daemon.
72 .TP
73 .BR "\-\-sessiond\-path PATH"
74 Set session daemon full binary path.
75 .TP
76 .BR "\-\-list\-options"
77 Simple listing of lttng options.
78 .TP
79 .BR "\-\-list\-commands"
80 Simple listing of lttng commands.
81 .SH "COMMANDS"
82
83 .PP
84 \fBadd-context\fP [OPTIONS]
85 .RS
86 Add context to event(s) and/or channel(s).
87
88 A context is basically extra information appended to a channel. For instance,
89 you could ask the tracer to add the PID information for all events in a
90 channel. You can also add performance monitoring unit counters (perf PMU) using
91 the perf kernel API).
92
93 For example, this command will add the context information 'prio' and two perf
94 counters (hardware branch misses and cache misses), to all events in the trace
95 data output:
96
97 .nf
98 # lttng add-context \-k \-t prio \-t perf:branch-misses \\
99 \-t perf:cache-misses
100 .fi
101
102 Please take a look at the help (\-h/\-\-help) for a detailed list of available
103 contexts.
104
105 If no channel is given (\-c), the context is added to all channels that were
106 already enabled. If the session has no channel, a default channel is created.
107 Otherwise the context will be added only to the given channel (\-c).
108
109 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
110 file.
111
112 .B OPTIONS:
113
114 .TP
115 .BR "\-h, \-\-help"
116 Show summary of possible options and commands.
117 .TP
118 .BR "\-s, \-\-session NAME"
119 Apply on session name.
120 .TP
121 .BR "\-c, \-\-channel NAME"
122 Apply on channel name.
123 .TP
124 .BR "\-k, \-\-kernel"
125 Apply for the kernel tracer
126 .TP
127 .BR "\-u, \-\-userspace"
128 Apply for the user-space tracer
129 .TP
130 .BR "\-t, \-\-type TYPE"
131 Context type. You can repeat this option on the command line. Please
132 use "lttng add-context \-h" to list all available types.
133 .RE
134 .PP
135
136 .PP
137 \fBcalibrate\fP [OPTIONS]
138 .RS
139 Quantify LTTng overhead
140
141 The LTTng calibrate command can be used to find out the combined average
142 overhead of the LTTng tracer and the instrumentation mechanisms used. This
143 overhead can be calibrated in terms of time or using any of the PMU performance
144 counter available on the system.
145
146 For now, the only calibration implemented is that of the kernel function
147 instrumentation (kretprobes).
148
149 * Calibrate kernel function instrumentation
150
151 Let's use an example to show this calibration. We use an i7 processor with 4
152 general-purpose PMU registers. This information is available by issuing dmesg,
153 looking for "generic registers".
154
155 This sequence of commands will gather a trace executing a kretprobe hooked on
156 an empty function, gathering PMU counters LLC (Last Level Cache) misses
157 information (see lttng add-context \-\-help to see the list of available PMU
158 counters).
159
160 .nf
161 # lttng create calibrate-function
162 # lttng enable-event calibrate \-\-kernel \\
163 \-\-function lttng_calibrate_kretprobe
164 # lttng add-context \-\-kernel \-t perf:LLC-load-misses \\
165 \-t perf:LLC-store-misses \\
166 \-t perf:LLC-prefetch-misses
167 # lttng start
168 # for a in $(seq 1 10); do \\
169 lttng calibrate \-\-kernel \-\-function;
170 done
171 # lttng destroy
172 # babeltrace $(ls \-1drt ~/lttng-traces/calibrate-function-* \\
173 | tail \-n 1)
174 .fi
175
176 The output from babeltrace can be saved to a text file and opened in a
177 spreadsheet (e.g. oocalc) to focus on the per-PMU counter delta between
178 consecutive "calibrate_entry" and "calibrate_return" events. Note that these
179 counters are per-CPU, so scheduling events would need to be present to account
180 for migration between CPU. Therefore, for calibration purposes, only events
181 staying on the same CPU must be considered.
182
183 The average result, for the i7, on 10 samples:
184
185 .nf
186 Average Std.Dev.
187 perf_LLC_load_misses: 5.0 0.577
188 perf_LLC_store_misses: 1.6 0.516
189 perf_LLC_prefetch_misses: 9.0 14.742
190 .fi
191
192 As we can notice, the load and store misses are relatively stable across runs
193 (their standard deviation is relatively low) compared to the prefetch misses.
194 We can conclude from this information that LLC load and store misses can be
195 accounted for quite precisely, but prefetches within a function seems to behave
196 too erratically (not much causality link between the code executed and the CPU
197 prefetch activity) to be accounted for.
198
199 .B OPTIONS:
200
201 .TP
202 .BR "\-h, \-\-help"
203 Show summary of possible options and commands.
204 .TP
205 .BR "\-k, \-\-kernel"
206 Apply for the kernel tracer
207 .TP
208 .BR "\-u, \-\-userspace"
209 Apply for the user-space tracer
210 .TP
211 .BR "\-\-function"
212 Dynamic function entry/return probe (default)
213 .RE
214 .PP
215
216 .PP
217 .IP \fBcreate\fP [NAME] [OPTIONS]
218 .RS
219 Create tracing session.
220
221 A tracing session contains channel(s) which contains event(s). It is domain
222 agnostic meaning that you can enable channels and events for either the
223 user-space tracer and/or the kernel tracer. It acts like a container
224 aggregating multiple tracing sources.
225
226 On creation, a \fB.lttngrc\fP file is created in your $HOME directory
227 containing the current session name. If NAME is omitted, a session name is
228 automatically created having this form: 'auto-yyyymmdd-hhmmss'.
229
230 If no \fB\-o, \-\-output\fP is specified, the traces will be written in
231 $HOME/lttng-traces.
232
233 The $HOME environment variable can be overridden by defining the environment
234 variable LTTNG_HOME. This is useful when the user running the commands has
235 a non-writeable home directory.
236
237 .B OPTIONS:
238
239 .TP
240 .BR "\-h, \-\-help"
241 Show summary of possible options and commands.
242 .TP
243 .BR "\-\-list-options"
244 Simple listing of options
245 .TP
246 .BR "\-o, \-\-output PATH"
247 Specify output path for traces
248 .TP
249 .BR "\-\-no-output"
250 Traces will not be outputed
251 .TP
252 .BR "\-\-snapshot"
253 Set the session in snapshot mode. Created in no-output mode and uses the
254 URL, if one, as the default snapshot output. Every channel will be set
255 in overwrite mode and with mmap output (splice not supported).
256
257 .TP
258 .BR "\-U, \-\-set-url=URL"
259 Set URL for the consumer output destination. It is persistent for the
260 session lifetime. Redo the command to change it. This will set both data
261 and control URL for network.
262 .TP
263 .BR "\-C, \-\-ctrl-url=URL"
264 Set control path URL. (Must use -D also)
265 .TP
266 .BR "\-D, \-\-data-url=URL"
267 Set data path URL. (Must use -C also)
268 .PP
269 Using these options, each API call can be controlled individually. For
270 instance, \-C does not enable the consumer automatically. You'll need the \-e
271 option for that.
272
273 .B URL FORMAT:
274
275 proto://[HOST|IP][:PORT1[:PORT2]][/TRACE_PATH]
276
277 Supported protocols are (proto):
278 .TP
279 .BR "file://..."
280 Local filesystem full path.
281
282 .TP
283 .BR "net://..."
284 This will use the default network transport layer which is TCP for both
285 control (PORT1) and data port (PORT2). The default ports are
286 respectively 5342 and 5343. Note that net[6]:// is not yet supported.
287
288 .TP
289 .BR "tcp[6]://..."
290 Can only be used with -C and -D together
291
292 NOTE: IPv6 address MUST be enclosed in brackets '[]' (rfc2732)
293
294 .B EXAMPLES:
295
296 .nf
297 # lttng create -U net://192.168.1.42
298 .fi
299 Uses TCP and default ports for the given destination.
300
301 .nf
302 # lttng create -U net6://[fe80::f66d:4ff:fe53:d220]
303 .fi
304 Uses TCP, default ports and IPv6.
305
306 .nf
307 # lttng create s1 -U net://myhost.com:3229
308 .fi
309 Create session s1 and set its consumer to myhost.com on port 3229 for control.
310 .RE
311 .PP
312
313 .PP
314 \fBdestroy\fP [NAME] [OPTIONS]
315 .RS
316 Teardown tracing session
317
318 Free memory on the session daemon and tracer side. It's gone!
319
320 If NAME is omitted, the session name is taken from the .lttngrc file.
321
322 .B OPTIONS:
323
324 .TP
325 .BR "\-h, \-\-help"
326 Show summary of possible options and commands.
327 .TP
328 .BR "\-a, \-\-all"
329 Destroy all sessions
330 .TP
331 .BR "\-\-list-options"
332 Simple listing of options
333 .RE
334 .PP
335
336 .PP
337 \fBenable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
338 .RS
339 Enable tracing channel
340
341 To enable an event, you must enable both the event and the channel that
342 contains it.
343
344 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
345 file.
346
347 Exactly one of \-k or -u must be specified.
348
349 It is important to note that if a certain type of buffers is used, the session
350 will be set with that type and all other subsequent channel needs to have the
351 same type.
352
353 Note that once the session has been started and enabled on the tracer side,
354 it's not possible anymore to enable a new channel for that session.
355
356 .B OPTIONS:
357
358 .TP
359 .BR "\-h, \-\-help"
360 Show this help
361 .TP
362 .BR "\-\-list-options"
363 Simple listing of options
364 .TP
365 .BR "\-s, \-\-session NAME"
366 Apply on session name
367 .TP
368 .BR "\-k, \-\-kernel"
369 Apply to the kernel tracer
370 .TP
371 .BR "\-u, \-\-userspace"
372 Apply to the user-space tracer
373 .TP
374 .BR "\-\-discard"
375 Discard event when subbuffers are full (default)
376 .TP
377 .BR "\-\-overwrite"
378 Flight recorder mode : overwrites events when subbuffers are full
379 .TP
380 .BR "\-\-subbuf-size SIZE"
381 Subbuffer size in bytes {+k,+M,+G}.
382 (default UST uid: 131072, UST pid: 4096, kernel: 262144, metadata: 4096)
383 Rounded up to the next power of 2.
384
385 The minimum subbuffer size, for each tracer, is the max value between
386 the default above and the system page size. You can issue this command
387 to get the current page size on your system: \fB$ getconf PAGE_SIZE\fP
388 .TP
389 .BR "\-\-num-subbuf NUM"
390 Number of subbuffers. (default UST uid: 4, UST pid: 4, kernel: 4,
391 metadata: 2) Rounded up to the next power of 2.
392 .TP
393 .BR "\-\-switch-timer USEC"
394 Switch subbuffer timer interval in ┬Ásec.
395 (default UST uid: 0, UST pid: 0, kernel: 0, metadata: 0)
396 .TP
397 .BR "\-\-read-timer USEC"
398 Read timer interval in ┬Ásec.
399 (default UST uid: 0, UST pid: 0, kernel: 200000, metadata: 0)
400 .TP
401 .BR "\-\-output TYPE"
402 Channel output type. Possible values: mmap, splice
403 (default UST uid: mmap, UST pid: mmap, kernel: splice, metadata: mmap)
404 .TP
405 .BR "\-\-buffers-uid"
406 Use per UID buffer (\-u only). Buffers are shared between applications
407 that have the same UID.
408 .TP
409 .BR "\-\-buffers-pid"
410 Use per PID buffer (\-u only). Each application has its own buffers.
411 .TP
412 .BR "\-\-buffers-global"
413 Use shared buffer for the whole system (\-k only)
414 .TP
415 .BR "\-C, \-\-tracefile-size SIZE"
416 Maximum size of each tracefile within a stream (in bytes).
417 0 means unlimited. (default: 0)
418 .TP
419 .BR "\-W, \-\-tracefile-count COUNT"
420 Used in conjunction with \-C option, this will limit the number of files
421 created to the specified count. 0 means unlimited. (default: 0)
422
423 .B EXAMPLES:
424
425 .nf
426 $ lttng enable-channel -k -C 4096 -W 32 chan1
427 .fi
428 For each stream, the maximum size of each trace file will be 4096 bytes, and
429 there will be a maximum of 32 different files. The file count is appended after
430 the stream number as seen in the following example. The last trace file is
431 smaller than 4096 since it was not completely filled.
432
433 .nf
434 ~/lttng-traces/[...]/chan1_0_0 (4096)
435 ~/lttng-traces/[...]/chan1_0_1 (4096)
436 ~/lttng-traces/[...]/chan1_0_2 (3245)
437 ~/lttng-traces/[...]/chan1_1_0 (4096)
438 ...
439 .fi
440
441 .nf
442 $ lttng enable-channel -k -C 4096
443 .fi
444 This will create trace files of 4096 bytes and will create new ones as long as
445 there is data available.
446 .RE
447 .PP
448
449 .PP
450 \fBenable-event\fP NAME[,NAME2,...] [-k|-u] [OPTIONS]
451 .RS
452 Enable tracing event
453
454 A tracing event is always assigned to a channel. If \fB\-c, \-\-channel\fP is
455 omitted, a default channel named '\fBchannel0\fP' is created and the event is
456 added to it. For the user-space tracer, using \fB\-a, \-\-all\fP is the same as
457 using the wildcard "*".
458
459 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
460 file.
461
462 .B OPTIONS:
463
464 .TP
465 .BR "\-h, \-\-help"
466 Show summary of possible options and commands.
467 .TP
468 .BR "\-\-list-options"
469 Simple listing of options
470 .TP
471 .BR "\-s, \-\-session NAME"
472 Apply on session name
473 .TP
474 .BR "\-c, \-\-channel NAME"
475 Apply on channel name
476 .TP
477 .BR "\-a, \-\-all"
478 Enable all tracepoints and syscalls. This actually enable a single
479 wildcard event "*".
480 .TP
481 .BR "\-k, \-\-kernel"
482 Apply for the kernel tracer
483 .TP
484 .BR "\-u, \-\-userspace"
485 Apply for the user-space tracer
486 .TP
487 .BR "\-\-tracepoint"
488 Tracepoint event (default). Userspace tracer supports wildcards at end
489 of string. Don't forget to quote to deal with bash expansion.
490 e.g.:
491 .nf
492 "*"
493 "app_component:na*"
494 .fi
495 .TP
496 .BR "\-\-loglevel NAME"
497 Tracepoint loglevel range from 0 to loglevel. Listed in the help (\-h).
498 .TP
499 .BR "\-\-loglevel-only NAME"
500 Tracepoint loglevel (only this loglevel).
501 The loglevel or loglevel-only options should be combined with a
502 tracepoint name or tracepoint wildcard.
503 .TP
504 .BR "\-\-probe (addr | symbol | symbol+offset)"
505 Dynamic probe. Addr and offset can be octal (0NNN...), decimal (NNN...)
506 or hexadecimal (0xNNN...)
507 .TP
508 .BR "\-\-function (addr | symbol | symbol+offset)"
509 Dynamic function entry/return probe. Addr and offset can be octal
510 (0NNN...), decimal (NNN...) or hexadecimal (0xNNN...)
511 .TP
512 .BR "\-\-syscall"
513 System call event. Enabling syscalls tracing (kernel tracer), you will
514 not be able to disable them with disable-event. This is a known
515 limitation. You can disable the entire channel to do the trick.
516 .TP
517 .BR "\-\-filter 'expression'"
518 Set a filter on a newly enabled event. Filter expression on event
519 fields and context. Event recording depends on evaluation. Only
520 specify on first activation of a given event within a session.
521 Filter only allowed when enabling events within a session before
522 tracing is started. If the filter fails to link with the event
523 within the traced domain, the event will be discarded.
524 Currently, filter is only implemented for the user-space tracer.
525
526 Expression examples:
527
528 .nf
529 'intfield > 500 && intfield < 503'
530 '(strfield == "test" || intfield != 10) && intfield > 33'
531 'doublefield > 1.1 && intfield < 5.3'
532 .fi
533
534 Wildcards are allowed at the end of strings:
535 'seqfield1 == "te*"'
536 In string literals, the escape character is a '\\'. Use '\\*' for
537 the '*' character, and '\\\\' for the '\\' character. Wildcard
538 match any sequence of characters, including an empty sub-string
539 (match 0 or more characters).
540
541 Context information can be used for filtering. The examples below show
542 usage of context filtering on process name (with a wildcard), process ID
543 range, and unique thread ID for filtering. The process and thread ID of
544 running applications can be found under columns "PID" and "LWP" of the
545 "ps -eLf" command.
546
547 .nf
548 '$ctx.procname == "demo*"'
549 '$ctx.vpid >= 4433 && $ctx.vpid < 4455'
550 '$ctx.vtid == 1234'
551 .fi
552
553 .RE
554 .PP
555
556 .PP
557 \fBdisable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
558 .RS
559 Disable tracing channel
560
561 Disabling a channel makes all event(s) in that channel to stop tracing. You can
562 enable it back by calling \fBlttng enable-channel NAME\fP again.
563
564 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
565 file.
566
567 .B OPTIONS:
568
569 .TP
570 .BR "\-h, \-\-help"
571 Show summary of possible options and commands.
572 .TP
573 .BR "\-\-list-options"
574 Simple listing of options
575 .TP
576 .BR "\-s, \-\-session NAME"
577 Apply on session name
578 .TP
579 .BR "\-k, \-\-kernel"
580 Apply for the kernel tracer
581 .TP
582 .BR "\-u, \-\-userspace"
583 Apply for the user-space tracer
584 .RE
585 .PP
586
587 .PP
588 \fBdisable-event\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
589 .RS
590 Disable tracing event
591
592 The event, once disabled, can be re-enabled by calling \fBlttng enable-event
593 NAME\fP again.
594
595 If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
596 file.
597
598 .B OPTIONS:
599
600 .TP
601 .BR "\-h, \-\-help"
602 Show summary of possible options and commands.
603 .TP
604 .BR "\-\-list-options"
605 Simple listing of options
606 .TP
607 .BR "\-s, \-\-session NAME"
608 Apply on session name
609 .TP
610 .BR "\-a, \-\-all-events"
611 Disable all events. This does NOT disable "*" but rather every known
612 events of the session.
613 .TP
614 .BR "\-k, \-\-kernel"
615 Apply for the kernel tracer
616 .TP
617 .BR "\-u, \-\-userspace"
618 Apply for the user-space tracer
619 .RE
620 .PP
621
622 .PP
623 \fBlist\fP [OPTIONS] [SESSION [SESSION OPTIONS]]
624 .RS
625 List tracing session information.
626
627 With no arguments, it will list available tracing session(s).
628
629 With the session name, it will display the details of the session including
630 the trace file path, the associated channels and their state (activated
631 and deactivated), the activated events and more.
632
633 With \-k alone, it will list all available kernel events (except the system
634 calls events).
635 With \-u alone, it will list all available user-space events from registered
636 applications. Here is an example of 'lttng list \-u':
637
638 .nf
639 PID: 7448 - Name: /tmp/lttng-ust/tests/hello/.libs/lt-hello
640 ust_tests_hello:tptest_sighandler (type: tracepoint)
641 ust_tests_hello:tptest (type: tracepoint)
642 .fi
643
644 You can now enable any event listed by using the name :
645 \fBust_tests_hello:tptest\fP.
646
647 .B OPTIONS:
648
649 .TP
650 .BR "\-h, \-\-help"
651 Show summary of possible options and commands.
652 .TP
653 .BR "\-\-list-options"
654 Simple listing of options
655 .TP
656 .BR "\-k, \-\-kernel"
657 Select kernel domain
658 .TP
659 .BR "\-u, \-\-userspace"
660 Select user-space domain.
661
662 .PP
663 .B SESSION OPTIONS:
664
665 .TP
666 .BR "\-c, \-\-channel NAME"
667 List details of a channel
668 .TP
669 .BR "\-d, \-\-domain"
670 List available domain(s)
671 .RE
672 .PP
673
674 .PP
675 \fBset-session\fP NAME [OPTIONS]
676 .RS
677 Set current session name
678
679 Will change the session name in the .lttngrc file.
680
681 .B OPTIONS:
682
683 .TP
684 .BR "\-h, \-\-help"
685 Show summary of possible options and commands.
686 .TP
687 .BR "\-\-list-options"
688 Simple listing of options
689 .RE
690 .PP
691
692 .PP
693 \fBsnapshot\fP [OPTIONS] ACTION
694 .RS
695 Snapshot command for LTTng session.
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
706 .PP
707 .B ACTION:
708
709 .TP
710 \fBadd-output\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] <URL> | -C <URL> -D <URL>
711
712 Setup and add an snapshot output for a session. Output are the destination
713 where the snapshot will be sent. Only one output is permitted. To change it,
714 you'll need to delete it and add back the new one.
715
716 .TP
717 \fBdel-output\fP ID | NAME [-s <NAME>]
718
719 Delete an output for a session using the ID. You can either specify the
720 output's ID that can be found with list-output or the name.
721
722 .TP
723 \fBlist-output\fP [-s <NAME>]
724
725 List the output of a session. Attributes of the output are printed.
726
727 .TP
728 \fBrecord\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] [<URL> | -C <URL> -D <URL>]
729
730 Snapshot a session's buffer(s) for all domains. If an URL is specified, it is
731 used instead of a previously added output. Specifying only a name or/and a max
732 size will override the current output values. For instance, you can record a
733 snapshot with a custom maximum size or with a different name.
734
735 .nf
736 $ lttng add-output -n mysnapshot file:///data/snapshot
737 [...]
738 $ lttng snapshot record -n new_name_snapshot
739 .fi
740
741 The above will create a snapshot in /data/snapshot/new_name_snapshot* directory
742 rather then in mysnapshot*/
743
744 .PP
745 .B DETAILED ACTION OPTIONS
746
747 .TP
748 .BR "\-s, \-\-session NAME"
749 Apply to session name.
750 .TP
751 .BR "\-n, \-\-name NAME"
752 Name of the snapshot's output.
753 .TP
754 .BR "\-m, \-\-max-size SIZE"
755 Maximum size in bytes of the snapshot. The maxium size does not include
756 the metadata file.
757 .TP
758 .BR "\-C, \-\-ctrl-url URL"
759 Set control path URL. (Must use -D also)
760 .TP
761 .BR "\-D, \-\-data-url URL"
762 Set data path URL. (Must use -C also)
763 .RE
764 .PP
765
766 .PP
767 \fBstart\fP [NAME] [OPTIONS]
768 .RS
769 Start tracing
770
771 It will start tracing for all tracers for a specific tracing session.
772 If NAME is omitted, the session name is taken from the .lttngrc file.
773
774 .B OPTIONS:
775
776 .TP
777 .BR "\-h, \-\-help"
778 Show summary of possible options and commands.
779 .TP
780 .BR "\-\-list-options"
781 Simple listing of options
782 .RE
783 .PP
784
785 .PP
786 \fBstop\fP [NAME] [OPTIONS]
787 .RS
788 Stop tracing
789
790 It will stop tracing for all tracers for a specific tracing session. Before
791 returning, the command checks for data availability meaning that it will wait
792 until the trace is readable for the session. Use \-\-no-wait to avoid this
793 behavior.
794
795 If NAME is omitted, the session name is taken from the .lttngrc file.
796
797 .B OPTIONS:
798
799 .TP
800 .BR "\-h, \-\-help"
801 Show summary of possible options and commands.
802 .TP
803 .BR "\-\-list-options"
804 Simple listing of options
805 .TP "\-\-no-wait"
806 Don't wait for data availability.
807 .RE
808 .PP
809
810 .PP
811 \fBversion\fP
812 .RS
813 Show version information
814
815 .B OPTIONS:
816
817 .TP
818 .BR "\-h, \-\-help"
819 Show summary of possible options and commands.
820 .TP
821 .BR "\-\-list-options"
822 Simple listing of options
823 .RE
824 .PP
825
826 .PP
827 \fBview\fP [SESSION_NAME] [OPTIONS]
828 .RS
829 View traces of a tracing session. By default, the babeltrace viewer
830 will be used for text viewing. If SESSION_NAME is omitted, the session
831 name is taken from the .lttngrc file.
832
833 .B OPTIONS:
834
835 .TP
836 .BR "\-h, \-\-help"
837 Show this help
838 .TP
839 .BR "\-\-list-options"
840 Simple listing of options
841 .TP
842 .BR "\-t, \-\-trace-path PATH"
843 Trace directory path for the viewer
844 .TP
845 .BR "\-e, \-\-viewer CMD"
846 Specify viewer and/or options to use This will completely override the
847 default viewers so please make sure to specify the full command. The
848 trace directory path of the session will be appended at the end to the
849 arguments
850 .RE
851 .PP
852
853 .SH "EXIT VALUES"
854 .PP
855 On success 0 is returned and a positive value on error. Value of 1 means a command
856 error, 2 an undefined command, 3 a fatal error and 4 a command warning meaning that
857 something went wrong during the command.
858
859 Any other value above 10, please refer to
860 .BR "<lttng/lttng-error.h>"
861 for a detailed list or use lttng_strerror() to get a human readable string of
862 the error code.
863 .PP
864
865 .SH "ENVIRONMENT VARIABLES"
866
867 .PP
868 Note that all command line options override environment variables.
869 .PP
870
871 .PP
872 .IP "LTTNG_SESSIOND_PATH"
873 Allows one to specify the full session daemon binary path to lttng command line
874 tool. You can also use \-\-sessiond-path option having the same effect.
875 .PP
876
877 .SH "SEE ALSO"
878 .BR babeltrace(1),
879 .BR lttng-ust(3),
880 .BR lttng-sessiond(8),
881 .BR lttng-relayd(8),
882 .BR lttng-health-check(3)
883
884 .SH "BUGS"
885
886 .PP
887 If you encounter any issues or usability problem, please report it on our
888 mailing list <lttng-dev@lists.lttng.org> to help improve this project or
889 at https://bugs.lttng.org which is a bugtracker.
890 .PP
891
892 .SH "CREDITS"
893
894 .PP
895 lttng is distributed under the GNU General Public License version 2. See the file
896 COPYING for details.
897 .PP
898 A Web site is available at http://lttng.org for more information on the LTTng
899 project.
900 .PP
901 You can also find our git tree at http://git.lttng.org.
902 .PP
903 Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
904 .PP
905 You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
906 .PP
907 .SH "THANKS"
908
909 .PP
910 Thanks to Yannick Brosseau without whom this project would never have been so
911 lean and mean! Also thanks to the Ericsson teams working on tracing which
912 helped us greatly with detailed bug reports and unusual test cases.
913
914 Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
915 maintainer) and Jon Bernard for our Debian packages.
916
917 Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
918 Montreal for the LTTng journey.
919 .PP
920 .SH "AUTHORS"
921
922 .PP
923 lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
924 David Goulet. More people have since contributed to it. It is currently
925 maintained by David Goulet <dgoulet@efficios.com>.
926 .PP
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