Manpage: cleanup layout of enable-channel
[lttng-tools.git] / doc / man / lttng.1
CommitLineData
391b9c72 1.TH "LTTNG" "1" "December 3rd, 2012" "" ""
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2
3.SH "NAME"
c5db699c 4lttng \(em LTTng 2.x tracer control command line tool
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5
6.SH "SYNOPSIS"
7
8.PP
9.nf
10lttng [OPTIONS] <COMMAND>
11.fi
12.SH "DESCRIPTION"
13
14.PP
15The LTTng project aims at providing highly efficient tracing tools for Linux.
16It's tracers help tracking down performance issues and debugging problems
17involving multiple concurrent processes and threads. Tracing across multiple
18systems is also possible.
19
fa072eae 20The \fBlttng\fP command line tool from the lttng-tools package is used to control
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21both kernel and user-space tracing. Every interactions with the tracer should
22be done by this tool or by the liblttng-ctl provided with the lttng-tools
23package.
24
25LTTng uses a session daemon (lttng-sessiond(8)), acting as a tracing registry,
50a3b92a 26which allows you to interact with multiple tracers (kernel and user-space)
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27inside the same container, a tracing session. Traces can be gathered from the
28kernel and/or instrumented applications (lttng-ust(3)). Aggregating and reading
29those traces is done using the babeltrace(1) text viewer.
30
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31We introduce the notion of \fBtracing domains\fP which is essentially a type of
32tracer (kernel or user space for now). In the future, we could see a third
33tracer being for instance an hypervisor. For some commands, you'll need to
34specify on which domain the command applies (-u or -k). For instance, enabling
35a kernel event, you must specify the kernel domain to the command so we know
36for which tracer this event is for.
37
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38In order to trace the kernel, the session daemon needs to be running as root.
39LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is
40in that group can interact with the root session daemon and thus trace the
41kernel. Session daemons can co-exist meaning that you can have a session daemon
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42running as Alice that can be used to trace her applications along side with a
43root daemon or even a Bob daemon. We highly recommend to start the session
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44daemon at boot time for stable and long term tracing.
45
46Every user-space applications instrumented with lttng-ust(3), will
47automatically register to the session daemon. This feature gives you the
48ability to list available traceable applications and tracepoints on a per user
49basis. (See \fBlist\fP command).
50.SH "OPTIONS"
51
52.PP
53This program follow the usual GNU command line syntax with long options starting with
54two dashes. Below is a summary of the available options.
55.PP
56
57.TP
c9e32613 58.BR "\-h, \-\-help"
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59Show summary of possible options and commands.
60.TP
c9e32613 61.BR "\-v, \-\-verbose"
6991b181 62Increase verbosity.
d829b38c 63Three levels of verbosity are available which are triggered by putting additional v to
fa072eae 64the option (\-vv or \-vvv)
6991b181 65.TP
c9e32613 66.BR "\-q, \-\-quiet"
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67Suppress all messages (even errors).
68.TP
c9e32613 69.BR "\-g, \-\-group NAME"
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70Set unix tracing group name. (default: tracing)
71.TP
c9e32613 72.BR "\-n, \-\-no-sessiond"
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73Don't automatically spawn a session daemon.
74.TP
391b9c72 75.BR "\-\-sessiond\-path PATH"
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76Set session daemon full binary path.
77.TP
c9e32613 78.BR "\-\-list\-options"
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79Simple listing of lttng options.
80.TP
c9e32613 81.BR "\-\-list\-commands"
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82Simple listing of lttng commands.
83.SH "COMMANDS"
84
812a5eb7 85.PP
ee2758e5 86\fBadd-context\fP [OPTIONS]
812a5eb7 87.RS
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88Add context to event(s) and/or channel(s).
89
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90A context is basically extra information appended to a channel. For instance,
91you could ask the tracer to add the PID information for all events in a
92channel. You can also add performance monitoring unit counters (perf PMU) using
93the perf kernel API).
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94
95For example, this command will add the context information 'prio' and two perf
96counters (hardware branch misses and cache misses), to all events in the trace
97data output:
98
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99.nf
100# lttng add-context \-k \-t prio \-t perf:branch-misses \\
101 \-t perf:cache-misses
102.fi
6991b181 103
c9e32613 104Please take a look at the help (\-h/\-\-help) for a detailed list of available
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105contexts.
106
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107If no channel is given (\-c), the context is added to all channels that were
108already enabled. If the session has no channel, a default channel is created.
109Otherwise the context will be added only to the given channel (\-c).
6991b181 110
c9e32613 111If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
6991b181 112file.
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113
114.B OPTIONS:
115
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116.TP
117.BR "\-h, \-\-help"
118Show summary of possible options and commands.
119.TP
120.BR "\-s, \-\-session NAME"
121Apply on session name.
122.TP
123.BR "\-c, \-\-channel NAME"
124Apply on channel name.
125.TP
126.BR "\-k, \-\-kernel"
127Apply for the kernel tracer
128.TP
129.BR "\-u, \-\-userspace"
130Apply for the user-space tracer
131.TP
132.BR "\-t, \-\-type TYPE"
133Context type. You can repeat this option on the command line. Please
134use "lttng add-context \-h" to list all available types.
135.RE
136.PP
6991b181 137
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138.PP
139\fBcalibrate\fP [OPTIONS]
140.RS
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141Quantify LTTng overhead
142
143The LTTng calibrate command can be used to find out the combined average
144overhead of the LTTng tracer and the instrumentation mechanisms used. This
145overhead can be calibrated in terms of time or using any of the PMU performance
146counter available on the system.
147
148For now, the only calibration implemented is that of the kernel function
149instrumentation (kretprobes).
150
151* Calibrate kernel function instrumentation
152
153Let's use an example to show this calibration. We use an i7 processor with 4
154general-purpose PMU registers. This information is available by issuing dmesg,
155looking for "generic registers".
156
157This sequence of commands will gather a trace executing a kretprobe hooked on
158an empty function, gathering PMU counters LLC (Last Level Cache) misses
c9e32613 159information (see lttng add-context \-\-help to see the list of available PMU
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160counters).
161
22019883 162.nf
6991b181 163# lttng create calibrate-function
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164# lttng enable-event calibrate \-\-kernel \\
165 \-\-function lttng_calibrate_kretprobe
166# lttng add-context \-\-kernel \-t perf:LLC-load-misses \\
167 \-t perf:LLC-store-misses \\
168 \-t perf:LLC-prefetch-misses
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169# lttng start
170# for a in $(seq 1 10); do \\
c9e32613 171 lttng calibrate \-\-kernel \-\-function;
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172 done
173# lttng destroy
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174# babeltrace $(ls \-1drt ~/lttng-traces/calibrate-function-* \\
175 | tail \-n 1)
176.fi
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177
178The output from babeltrace can be saved to a text file and opened in a
179spreadsheet (e.g. oocalc) to focus on the per-PMU counter delta between
180consecutive "calibrate_entry" and "calibrate_return" events. Note that these
181counters are per-CPU, so scheduling events would need to be present to account
182for migration between CPU. Therefore, for calibration purposes, only events
183staying on the same CPU must be considered.
184
185The average result, for the i7, on 10 samples:
186
22019883 187.nf
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188 Average Std.Dev.
189perf_LLC_load_misses: 5.0 0.577
190perf_LLC_store_misses: 1.6 0.516
191perf_LLC_prefetch_misses: 9.0 14.742
22019883 192.fi
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193
194As we can notice, the load and store misses are relatively stable across runs
195(their standard deviation is relatively low) compared to the prefetch misses.
196We can conclude from this information that LLC load and store misses can be
197accounted for quite precisely, but prefetches within a function seems to behave
198too erratically (not much causality link between the code executed and the CPU
199prefetch activity) to be accounted for.
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200
201.B OPTIONS:
202
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203.TP
204.BR "\-h, \-\-help"
205Show summary of possible options and commands.
206.TP
207.BR "\-k, \-\-kernel"
208Apply for the kernel tracer
209.TP
210.BR "\-u, \-\-userspace"
211Apply for the user-space tracer
212.TP
213.BR "\-\-function"
214Dynamic function entry/return probe (default)
215.RE
216.PP
6991b181 217
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218.PP
219.IP \fBcreate\fP [NAME] [OPTIONS]
220.RS
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221Create tracing session.
222
223A tracing session contains channel(s) which contains event(s). It is domain
224agnostic meaning that you can enable channels and events for either the
225user-space tracer and/or the kernel tracer. It acts like a container
226aggregating multiple tracing sources.
227
228On creation, a \fB.lttngrc\fP file is created in your $HOME directory
229containing the current session name. If NAME is omitted, a session name is
fa072eae 230automatically created having this form: 'auto-yyyymmdd-hhmmss'.
6991b181 231
c9e32613 232If no \fB\-o, \-\-output\fP is specified, the traces will be written in
6991b181 233$HOME/lttng-traces.
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234
235The $HOME environment variable can be overridden by defining the environment
236variable LTTNG_HOME. This is useful when the user running the commands has
237a non-writeable home directory.
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238
239.B OPTIONS:
240
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241.TP
242.BR "\-h, \-\-help"
243Show summary of possible options and commands.
244.TP
245.BR "\-\-list-options"
246Simple listing of options
247.TP
248.BR "\-o, \-\-output PATH"
249Specify output path for traces
250.TP
251.BR "\-\-no-output"
252Traces will not be outputed
253.TP
254.BR "\-\-snapshot"
255Set the session in snapshot mode. Created in no-output mode and uses the
256URL, if one, as the default snapshot output. Every channel will be set
257in overwrite mode and with mmap output (splice not supported).
6b8f2e64 258
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259.TP
260.BR "\-U, \-\-set-url=URL"
261Set URL for the consumer output destination. It is persistent for the
262session lifetime. Redo the command to change it. This will set both data
263and control URL for network.
264.TP
265.BR "\-C, \-\-ctrl-url=URL"
266Set control path URL. (Must use -D also)
267.TP
268.BR "\-D, \-\-data-url=URL"
269Set data path URL. (Must use -C also)
270.PP
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271Using these options, each API call can be controlled individually. For
272instance, \-C does not enable the consumer automatically. You'll need the \-e
273option for that.
274
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275.B URL FORMAT:
276
277proto://[HOST|IP][:PORT1[:PORT2]][/TRACE_PATH]
278
279Supported protocols are (proto):
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280.TP
281.BR "file://..."
282Local filesystem full path.
785d2d0d 283
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284.TP
285.BR "net://..."
286This will use the default network transport layer which is TCP for both
287control (PORT1) and data port (PORT2). The default ports are
288respectively 5342 and 5343. Note that net[6]:// is not yet supported.
785d2d0d 289
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290.TP
291.BR "tcp[6]://..."
292Can only be used with -C and -D together
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293
294NOTE: IPv6 address MUST be enclosed in brackets '[]' (rfc2732)
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295
296.B EXAMPLES:
297
ee2758e5 298.nf
6b8f2e64 299# lttng create -U net://192.168.1.42
ee2758e5 300.fi
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301Uses TCP and default ports for the given destination.
302
ee2758e5 303.nf
6b8f2e64 304# lttng create -U net6://[fe80::f66d:4ff:fe53:d220]
ee2758e5 305.fi
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306Uses TCP, default ports and IPv6.
307
ee2758e5 308.nf
6b8f2e64 309# lttng create s1 -U net://myhost.com:3229
6991b181 310.fi
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311Create session s1 and set its consumer to myhost.com on port 3229 for control.
312.RE
313.PP
6991b181 314
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315.PP
316\fBdestroy\fP [NAME] [OPTIONS]
317.RS
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318Teardown tracing session
319
320Free memory on the session daemon and tracer side. It's gone!
321
322If NAME is omitted, the session name is taken from the .lttngrc file.
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323
324.B OPTIONS:
325
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326.TP
327.BR "\-h, \-\-help"
328Show summary of possible options and commands.
329.TP
330.BR "\-a, \-\-all"
331Destroy all sessions
332.TP
333.BR "\-\-list-options"
334Simple listing of options
335.RE
336.PP
6991b181 337
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338.PP
339\fBenable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
340.RS
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341Enable tracing channel
342
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343To enable an event, you must enable both the event and the channel that
344contains it.
b883c01b 345
c9e32613 346If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
6991b181 347file.
7972aab2 348
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349Exactly one of \-k or -u must be specified.
350
7972aab2 351It is important to note that if a certain type of buffers is used, the session
bd337b98 352will be set with that type and all other subsequent channel needs to have the
7972aab2 353same type.
bd337b98 354
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355Note that once the session has been started and enabled on the tracer side,
356it's not possible anymore to enable a new channel for that session.
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357
358.B OPTIONS:
359
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360.TP
361.BR "\-h, \-\-help"
362Show this help
363.TP
364.BR "\-\-list-options"
365Simple listing of options
366.TP
367.BR "\-s, \-\-session NAME"
368Apply on session name
369.TP
370.BR "\-k, \-\-kernel"
371Apply to the kernel tracer
372.TP
373.BR "\-u, \-\-userspace"
374Apply to the user-space tracer
375.TP
376.BR "\-\-discard"
377Discard event when subbuffers are full (default)
378.TP
379.BR "\-\-overwrite"
380Flight recorder mode : overwrites events when subbuffers are full
381.TP
382.BR "\-\-subbuf-size SIZE"
383Subbuffer size in bytes {+k,+M,+G}.
384(default UST uid: 131072, UST pid: 4096, kernel: 262144, metadata: 4096)
385Rounded up to the next power of 2.
386
387The minimum subbuffer size, for each tracer, is the max value between
388the default above and the system page size. You can issue this command
389to get the current page size on your system: \fB$ getconf PAGE_SIZE\fP
390.TP
391.BR "\-\-num-subbuf NUM"
392Number of subbuffers. (default UST uid: 4, UST pid: 4, kernel: 4,
393metadata: 2) Rounded up to the next power of 2.
394.TP
395.BR "\-\-switch-timer USEC"
396Switch subbuffer timer interval in µsec.
397(default UST uid: 0, UST pid: 0, kernel: 0, metadata: 0)
398.TP
399.BR "\-\-read-timer USEC"
400Read timer interval in µsec.
401(default UST uid: 0, UST pid: 0, kernel: 200000, metadata: 0)
402.TP
403.BR "\-\-output TYPE"
404Channel output type. Possible values: mmap, splice
405(default UST uid: mmap, UST pid: mmap, kernel: splice, metadata: mmap)
406.TP
407.BR "\-\-buffers-uid"
408Use per UID buffer (\-u only). Buffers are shared between applications
409that have the same UID.
410.TP
411.BR "\-\-buffers-pid"
412Use per PID buffer (\-u only). Each application has its own buffers.
413.TP
414.BR "\-\-buffers-global"
415Use shared buffer for the whole system (\-k only)
416.TP
417.BR "\-C, \-\-tracefile-size SIZE"
418Maximum size of each tracefile within a stream (in bytes).
4190 means unlimited. (default: 0)
420.TP
421.BR "\-W, \-\-tracefile-count COUNT"
422Used in conjunction with \-C option, this will limit the number of files
423created to the specified count. 0 means unlimited. (default: 0)
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424
425.B EXAMPLES:
426
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427.nf
428$ lttng enable-channel -k -C 4096 -W 32 chan1
429.fi
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430For each stream, the maximum size of each trace file will be 4096 bytes, and
431there will be a maximum of 32 different files. The file count is appended after
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432the stream number as seen in the following example. The last trace file is
433smaller than 4096 since it was not completely filled.
434
05be3802 435.nf
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436 ~/lttng-traces/[...]/chan1_0_0 (4096)
437 ~/lttng-traces/[...]/chan1_0_1 (4096)
438 ~/lttng-traces/[...]/chan1_0_2 (3245)
439 ~/lttng-traces/[...]/chan1_1_0 (4096)
440 ...
05be3802 441.fi
1624d5b7 442
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443.nf
444$ lttng enable-channel -k -C 4096
445.fi
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446This will create trace files of 4096 bytes and will create new ones as long as
447there is data available.
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448.RE
449.PP
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450
451.IP "\fBenable-event\fP NAME[,NAME2,...] [-k|-u] [OPTIONS]"
452.nf
453Enable tracing event
454
c9e32613 455A tracing event is always assigned to a channel. If \fB\-c, \-\-channel\fP is
6991b181 456omitted, a default channel named '\fBchannel0\fP' is created and the event is
c9e32613 457added to it. For the user-space tracer, using \fB\-a, \-\-all\fP is the same as
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458using the wildcard "*".
459
c9e32613 460If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
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461file.
462.fi
463
464.B OPTIONS:
465
466.nf
c9e32613 467\-h, \-\-help
6991b181 468 Show summary of possible options and commands.
c9e32613 469\-\-list-options
6991b181 470 Simple listing of options
391b9c72 471\-s, \-\-session NAME
6991b181 472 Apply on session name
391b9c72 473\-c, \-\-channel NAME
6991b181 474 Apply on channel name
c9e32613 475\-a, \-\-all
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476 Enable all tracepoints and syscalls. This actually enable a single
477 wildcard event "*".
c9e32613 478\-k, \-\-kernel
6991b181 479 Apply for the kernel tracer
c9e32613 480\-u, \-\-userspace
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481 Apply for the user-space tracer
482
c9e32613 483\-\-tracepoint
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484 Tracepoint event (default)
485 - userspace tracer supports wildcards at end of string. Don't forget to
486 quote to deal with bash expansion.
487 e.g.:
488 "*"
489 "app_component:na*"
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490\-\-loglevel NAME
491 Tracepoint loglevel range from 0 to loglevel. Listed in the help (\-h).
492\-\-loglevel-only NAME
493 Tracepoint loglevel (only this loglevel).
494
495 The loglevel or loglevel-only options should be combined with a
496 tracepoint name or tracepoint wildcard.
c9e32613 497\-\-probe [addr | symbol | symbol+offset]
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498 Dynamic probe. Addr and offset can be octal (0NNN...), decimal (NNN...)
499 or hexadecimal (0xNNN...)
c9e32613 500\-\-function [addr | symbol | symbol+offset]
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501 Dynamic function entry/return probe. Addr and offset can be octal
502 (0NNN...), decimal (NNN...) or hexadecimal (0xNNN...)
c9e32613 503\-\-syscall
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504 System call event. Enabling syscalls tracing (kernel tracer), you will
505 not be able to disable them with disable-event. This is a known
506 limitation. You can disable the entire channel to do the trick.
9bd578f5 507
919e300c 508\-\-filter 'expression'
6b8f2e64 509 Set a filter on a newly enabled event. Filter expression on event
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510 fields and context. Event recording depends on evaluation. Only
511 specify on first activation of a given event within a session.
512 Filter only allowed when enabling events within a session before
513 tracing is started. If the filter fails to link with the event
514 within the traced domain, the event will be discarded.
515 Currently, filter is only implemented for the user-space tracer.
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516
517 Expression examples:
518
519 'intfield > 500 && intfield < 503'
520 '(stringfield == "test" || intfield != 10) && intfield > 33'
521 'doublefield > 1.1 && intfield < 5.3'
522
523 Wildcards are allowed at the end of strings:
524 'seqfield1 == "te*"'
525 In string literals, the escape character is a '\\'. Use '\\*' for
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526 the '*' character, and '\\\\' for the '\\' character. Wildcard
527 match any sequence of characters, including an empty sub-string
528 (match 0 or more characters).
529
530 Context information can be used for filtering. The examples
531 below show usage of context filtering on process name (with a
532 wildcard), process ID range, and unique thread ID for filtering.
533 The process and thread ID of running applications can be found
534 under columns "PID" and "LWP" of the "ps -eLf" command.
535
536 '$ctx.procname == "demo*"'
537 '$ctx.vpid >= 4433 && $ctx.vpid < 4455'
538 '$ctx.vtid == 1234'
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539.fi
540
c9e32613 541.IP "\fBdisable-channel\fP NAME[,NAME2,...] [\-k|\-u] [OPTIONS]"
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542.nf
543Disable tracing channel
544
545Disabling a channel makes all event(s) in that channel to stop tracing. You can
546enable it back by calling \fBlttng enable-channel NAME\fP again.
547
c9e32613 548If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
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549file.
550.fi
551
552.B OPTIONS:
553
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554.nf
555\-h, \-\-help
556 Show summary of possible options and commands.
557\-\-list-options
558 Simple listing of options
559\-s, \-\-session NAME
6991b181 560 Apply on session name
c9e32613 561\-k, \-\-kernel
6991b181 562 Apply for the kernel tracer
c9e32613 563\-u, \-\-userspace
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564 Apply for the user-space tracer
565.fi
566
c9e32613 567.IP "\fBdisable-event\fP NAME[,NAME2,...] [\-k|\-u] [OPTIONS]"
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568.nf
569Disable tracing event
570
571The event, once disabled, can be re-enabled by calling \fBlttng enable-event
572NAME\fP again.
573
c9e32613 574If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
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575file.
576.fi
577
578.B OPTIONS:
579
580.nf
c9e32613 581\-h, \-\-help
6991b181 582 Show summary of possible options and commands.
c9e32613 583\-\-list-options
6991b181 584 Simple listing of options
391b9c72 585\-s, \-\-session NAME
6991b181 586 Apply on session name
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587\-a, \-\-all-events
588 Disable all events. This does NOT disable "*" but rather
589 every known events of the session.
c9e32613 590\-k, \-\-kernel
6991b181 591 Apply for the kernel tracer
c9e32613 592\-u, \-\-userspace
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593 Apply for the user-space tracer
594.fi
595
c9e32613 596.IP "\fBlist\fP [\-k|\-u] [SESSION [SESSION_OPTIONS]]"
6991b181 597.nf
c9e32613 598List tracing session information.
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599
600With no arguments, it will list available tracing session(s).
601
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602With the session name, it will display the details of the session including
603the trace file path, the associated channels and their state (activated
d829b38c 604and deactivated), the activated events and more.
fa072eae 605
c9e32613 606With \-k alone, it will list all available kernel events (except the system
6991b181 607calls events).
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608With \-u alone, it will list all available user-space events from registered
609applications. Here is an example of 'lttng list \-u':
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610
611PID: 7448 - Name: /tmp/lttng-ust/tests/hello/.libs/lt-hello
612 ust_tests_hello:tptest_sighandler (type: tracepoint)
613 ust_tests_hello:tptest (type: tracepoint)
614
615You can now enable any event listed by using the name :
616\fBust_tests_hello:tptest\fP.
617.fi
618
619.B OPTIONS:
620
621.nf
c9e32613 622\-h, \-\-help
6991b181 623 Show summary of possible options and commands.
c9e32613 624\-\-list-options
6991b181 625 Simple listing of options
c9e32613 626\-k, \-\-kernel
d829b38c 627 Select kernel domain
c9e32613 628\-u, \-\-userspace
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629 Select user-space domain.
630
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631.B SESSION OPTIONS:
632
c9e32613 633\-c, \-\-channel NAME
6991b181 634 List details of a channel
c9e32613 635\-d, \-\-domain
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636 List available domain(s)
637.fi
638
639.IP "\fBset-session\fP NAME"
640.nf
641Set current session name
642
643Will change the session name in the .lttngrc file.
644.fi
645
646.B OPTIONS:
647
648.nf
c9e32613 649\-h, \-\-help
6991b181 650 Show summary of possible options and commands.
c9e32613 651\-\-list-options
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652 Simple listing of options
653.fi
654
655.IP
656
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657.IP "\fBsnapshot\fP ACTION"
658.nf
659Snapshot command for LTTng session.
660.fi
661
662.B OPTIONS:
663
664.nf
665\-h, \-\-help
666 Show summary of possible options and commands.
667\-\-list-options
668 Simple listing of options
669.fi
670
671.B ACTION:
672
673.nf
674\fBadd-output\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] <URL> | -C <URL> -D <URL>
675
676Setup and add an snapshot output for a session. Output are the destination
677where the snapshot will be sent. Only one output is permitted. To change it,
678you'll need to delete it and add back the new one.
679
680\fBdel-output\fP ID | NAME [-s <NAME>]
681
682Delete an output for a session using the ID. You can either specify the
683output's ID that can be found with list-output or the name.
684
685\fBlist-output\fP [-s <NAME>]
686
687List the output of a session. Attributes of the output are printed.
688
689\fBrecord\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] [<URL> | -C <URL> -D <URL>]
690
691Snapshot a session's buffer(s) for all domains. If an URL is specified, it is
692used instead of a previously added output. Specifying only a name or/and a max
693size will override the current output values. For instance, you can record a
694snapshot with a custom maximum size or with a different name.
695
696$ lttng add-output -n mysnapshot file:///data/snapshot
697[...]
698$ lttng snapshot record -n new_name_snapshot
699
700The above will create a snapshot in /data/snapshot/new_name_snapshot* directory
701rather then in mysnapshot*/
702.fi
703
704.B LONG OPTIONS
705
706.nf
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707\-s, \-\-session NAME
708 Apply to session name.
709\-n, \-\-name NAME
710 Name of the snapshot's output.
711\-m, \-\-max-size SIZE
712 Maximum size in bytes of the snapshot. The maxium size does not
713 include the metadata file.
714\-C, \-\-ctrl-url URL
715 Set control path URL. (Must use -D also)
716\-D, \-\-data-url URL
717 Set data path URL. (Must use -C also)
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718.fi
719
720.IP
721
6b8f2e64 722.IP "\fBstart\fP [NAME] [OPTIONS]"
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723.nf
724Start tracing
725
726It will start tracing for all tracers for a specific tracing session.
727
728If NAME is omitted, the session name is taken from the .lttngrc file.
729.fi
730
731.B OPTIONS:
732
733.nf
c9e32613 734\-h, \-\-help
6991b181 735 Show summary of possible options and commands.
c9e32613 736\-\-list-options
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737 Simple listing of options
738.fi
739
740.IP
741
6b8f2e64 742.IP "\fBstop\fP [NAME] [OPTIONS]"
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743.nf
744Stop tracing
745
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746It will stop tracing for all tracers for a specific tracing session. Before
747returning, the command checks for data availability meaning that it will wait
748until the trace is readable for the session. Use \-\-no-wait to avoid this
749behavior.
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750
751If NAME is omitted, the session name is taken from the .lttngrc file.
752.fi
753
754.B OPTIONS:
755
756.nf
c9e32613 757\-h, \-\-help
6991b181 758 Show summary of possible options and commands.
c9e32613 759\-\-list-options
6991b181 760 Simple listing of options
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761\-\-no-wait
762 Don't wait for data availability.
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763.fi
764
765.IP
766
767.IP "\fBversion\fP"
768.nf
769Show version information
770.fi
771
772.B OPTIONS:
773
774.nf
c9e32613 775\-h, \-\-help
6991b181 776 Show summary of possible options and commands.
c9e32613 777\-\-list-options
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778 Simple listing of options
779.fi
780
781.IP
782
783.IP "\fBview\fP [SESSION_NAME] [OPTIONS]"
784.nf
785View traces of a tracing session
786
787By default, the babeltrace viewer will be used for text viewing.
788
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789If SESSION_NAME is omitted, the session name is taken from the .lttngrc file.
790
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791.fi
792
793.B OPTIONS:
794
795.nf
c9e32613 796\-h, \-\-help
6991b181 797 Show this help
c9e32613 798\-\-list-options
6991b181 799 Simple listing of options
c9e32613 800\-t, \-\-trace-path PATH
6991b181 801 Trace directory path for the viewer
c9e32613 802\-e, \-\-viewer CMD
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803 Specify viewer and/or options to use
804 This will completely override the default viewers so
805 please make sure to specify the full command. The trace
806 directory path of the session will be appended at the end
807 to the arguments
808.fi
809
c206d957 810.SH "EXIT VALUES"
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811On success 0 is returned and a positive value on error. Value of 1 means a command
812error, 2 an undefined command, 3 a fatal error and 4 a command warning meaning that
813something went wrong during the command.
c206d957 814
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815Any other value above 10, please refer to
816.BR <lttng/lttng-error.h>
817for a detailed list or use lttng_strerror() to get a human readable string of
818the error code.
c206d957 819
c206d957 820.PP
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821.SH "ENVIRONMENT VARIABLES"
822
823.PP
824Note that all command line options override environment variables.
825.PP
826
827.PP
05833633 828.IP "LTTNG_SESSIOND_PATH"
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829Allows one to specify the full session daemon binary path to lttng command line
830tool. You can also use \-\-sessiond-path option having the same effect.
6991b181 831.SH "SEE ALSO"
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832.BR babeltrace(1),
833.BR lttng-ust(3),
834.BR lttng-sessiond(8),
835.BR lttng-relayd(8),
836.BR lttng-health-check(3)
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837.SH "BUGS"
838
6991b181 839If you encounter any issues or usability problem, please report it on our
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840mailing list <lttng-dev@lists.lttng.org> to help improve this project or
841at https://bugs.lttng.org which is a bugtracker.
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842.SH "CREDITS"
843
844.PP
c9e32613 845lttng is distributed under the GNU General Public License version 2. See the file
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846COPYING for details.
847.PP
848A Web site is available at http://lttng.org for more information on the LTTng
849project.
850.PP
851You can also find our git tree at http://git.lttng.org.
852.PP
853Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
854.PP
855You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
856.PP
857.SH "THANKS"
858
859.PP
860Thanks to Yannick Brosseau without whom this project would never have been so
861lean and mean! Also thanks to the Ericsson teams working on tracing which
fa072eae 862helped us greatly with detailed bug reports and unusual test cases.
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863
864Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
865maintainer) and Jon Bernard for our Debian packages.
866
867Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
868Montreal for the LTTng journey.
c9e32613 869.PP
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870.SH "AUTHORS"
871
872.PP
873lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
874David Goulet. More people have since contributed to it. It is currently
875maintained by David Goulet <dgoulet@efficios.com>.
876.PP
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