Docs: clarify lttng.1 shm-path section
[lttng-tools.git] / doc / man / lttng.1
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516f6cbe 1.TH "LTTNG" "1" "May 13th, 2014" "" ""
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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
6991b181 9lttng [OPTIONS] <COMMAND>
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10.SH "DESCRIPTION"
11
12.PP
13The LTTng project aims at providing highly efficient tracing tools for Linux.
e256d661 14Its tracers help track down performance issues and debug problems
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15involving multiple concurrent processes and threads. Tracing across multiple
16systems is also possible.
17
fa072eae 18The \fBlttng\fP command line tool from the lttng-tools package is used to control
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19both kernel and user-space tracing. Every interaction with the tracer should
20be done by this tool or by the liblttng-ctl library provided by the lttng-tools
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21package.
22
23LTTng uses a session daemon (lttng-sessiond(8)), acting as a tracing registry,
50a3b92a 24which allows you to interact with multiple tracers (kernel and user-space)
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25inside the same container, a tracing session. Traces can be gathered from the
26kernel and/or instrumented applications (lttng-ust(3)). Aggregating and reading
27those traces is done using the babeltrace(1) text viewer.
28
50a3b92a 29We introduce the notion of \fBtracing domains\fP which is essentially a type of
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30tracer (kernel, user space, JUL, LOG4J or Python for now). In the future, we
31could see more tracer like for instance an hypervisor. For some commands,
32you'll need to specify on which domain the command operates (\-u, \-k, \-l, \-j
33or \-p). For instance, the kernel domain must be specified when enabling a
34kernel event.
50a3b92a 35
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36In order to trace the kernel, the session daemon needs to be running as root.
37LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is
38in that group can interact with the root session daemon and thus trace the
e256d661 39kernel. Session daemons can co-exist, meaning that you can have a session daemon
fa072eae 40running as Alice that can be used to trace her applications along side with a
e256d661 41root daemon or even a Bob daemon. We highly recommend starting the session
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42daemon at boot time for stable and long term tracing.
43
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44Each user-space application instrumented with lttng-ust(3) will automatically
45register with the root session daemon and its user session daemon. This allows
46each daemon to list the available traceable applications and tracepoints at any
47given moment (See the \fBlist\fP command).
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48.SH "OPTIONS"
49
50.PP
51This program follow the usual GNU command line syntax with long options starting with
52two dashes. Below is a summary of the available options.
53.PP
54
55.TP
c9e32613 56.BR "\-h, \-\-help"
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57Show summary of possible options and commands.
58.TP
c9e32613 59.BR "\-v, \-\-verbose"
6991b181 60Increase verbosity.
d829b38c 61Three levels of verbosity are available which are triggered by putting additional v to
fa072eae 62the option (\-vv or \-vvv)
6991b181 63.TP
c9e32613 64.BR "\-q, \-\-quiet"
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65Suppress all messages (even errors).
66.TP
c9e32613 67.BR "\-g, \-\-group NAME"
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68Set unix tracing group name. (default: tracing)
69.TP
c9e32613 70.BR "\-n, \-\-no-sessiond"
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71Don't automatically spawn a session daemon.
72.TP
391b9c72 73.BR "\-\-sessiond\-path PATH"
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74Set session daemon full binary path.
75.TP
c9e32613 76.BR "\-\-list\-options"
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77Simple listing of lttng options.
78.TP
c9e32613 79.BR "\-\-list\-commands"
6991b181 80Simple listing of lttng commands.
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81.TP
82.BR "\-m, \-\-mi TYPE
83Machine interface
84
85TYPE supported: XML
86
87Machine interface (MI) mode converts the traditional pretty printing to a
88machine output syntax. MI mode provides a format change-resistant way to access
89information generated via the lttng command line.
90
91When using MI mode, the data is printed on \fBstdout\fP. Error and warning are
92printed on \fBstderr\fP with the pretty print default format.
93
94If any errors occur during the execution of a command, the return value of the
95command will be different than zero. In this case, lttng does NOT guarantee the
96syntax and data validity of the generated MI output.
97
98For XML output type, a schema definition (XSD) file used for validation can be
99found under src/common/mi_lttng.xsd
100
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101.SH "COMMANDS"
102
812a5eb7 103.PP
ee2758e5 104\fBadd-context\fP [OPTIONS]
812a5eb7 105.RS
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106Add context to event(s) and/or channel(s).
107
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108A context is basically extra information appended to a channel. For instance,
109you could ask the tracer to add the PID information for all events in a
110channel. You can also add performance monitoring unit counters (perf PMU) using
aa3514e9 111the perf kernel API.
6991b181 112
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113For example, this command will add the context information 'prio' and two per-CPU
114perf counters (hardware branch misses and cache misses), to all events in the trace
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115data output:
116
812a5eb7 117.nf
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118# lttng add-context \-k \-t prio \-t perf:cpu:branch-misses \\
119 \-t perf:cpu:cache-misses
812a5eb7 120.fi
6991b181 121
c9e32613 122Please take a look at the help (\-h/\-\-help) for a detailed list of available
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123contexts.
124
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125Perf counters are available as per-CPU ("perf:cpu:...") and per-thread
126("perf:thread:...") counters. Currently, per-CPU counters can only be
127used with the kernel tracing domain, and per-thread counters can only be
128used with the UST tracing domain.
129
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130If no channel is given (\-c), the context is added to all channels that were
131already enabled. If the session has no channel, a default channel is created.
31ea4846 132Otherwise the context will be added only to the given channel (\-c).
6991b181 133
c9e32613 134If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
6991b181 135file.
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136
137.B OPTIONS:
138
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139.TP
140.BR "\-h, \-\-help"
141Show summary of possible options and commands.
142.TP
143.BR "\-s, \-\-session NAME"
144Apply on session name.
145.TP
146.BR "\-c, \-\-channel NAME"
147Apply on channel name.
148.TP
149.BR "\-k, \-\-kernel"
150Apply for the kernel tracer
151.TP
152.BR "\-u, \-\-userspace"
153Apply for the user-space tracer
154.TP
155.BR "\-t, \-\-type TYPE"
156Context type. You can repeat this option on the command line. Please
157use "lttng add-context \-h" to list all available types.
158.RE
159.PP
6991b181 160
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161.PP
162\fBcalibrate\fP [OPTIONS]
163.RS
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164Quantify LTTng overhead
165
166The LTTng calibrate command can be used to find out the combined average
167overhead of the LTTng tracer and the instrumentation mechanisms used. This
168overhead can be calibrated in terms of time or using any of the PMU performance
169counter available on the system.
170
171For now, the only calibration implemented is that of the kernel function
172instrumentation (kretprobes).
173
174* Calibrate kernel function instrumentation
175
176Let's use an example to show this calibration. We use an i7 processor with 4
177general-purpose PMU registers. This information is available by issuing dmesg,
178looking for "generic registers".
179
180This sequence of commands will gather a trace executing a kretprobe hooked on
181an empty function, gathering PMU counters LLC (Last Level Cache) misses
c9e32613 182information (see lttng add-context \-\-help to see the list of available PMU
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183counters).
184
22019883 185.nf
6991b181 186# lttng create calibrate-function
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187# lttng enable-event calibrate \-\-kernel \\
188 \-\-function lttng_calibrate_kretprobe
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189# lttng add-context \-\-kernel \-t perf:cpu:LLC-load-misses \\
190 \-t perf:cpu:LLC-store-misses \\
191 \-t perf:cpu:LLC-prefetch-misses
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192# lttng start
193# for a in $(seq 1 10); do \\
c9e32613 194 lttng calibrate \-\-kernel \-\-function;
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195 done
196# lttng destroy
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197# babeltrace $(ls \-1drt ~/lttng-traces/calibrate-function-* \\
198 | tail \-n 1)
199.fi
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200
201The output from babeltrace can be saved to a text file and opened in a
202spreadsheet (e.g. oocalc) to focus on the per-PMU counter delta between
203consecutive "calibrate_entry" and "calibrate_return" events. Note that these
204counters are per-CPU, so scheduling events would need to be present to account
205for migration between CPU. Therefore, for calibration purposes, only events
206staying on the same CPU must be considered.
207
208The average result, for the i7, on 10 samples:
209
22019883 210.nf
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211 Average Std.Dev.
212perf_LLC_load_misses: 5.0 0.577
213perf_LLC_store_misses: 1.6 0.516
214perf_LLC_prefetch_misses: 9.0 14.742
22019883 215.fi
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216
217As we can notice, the load and store misses are relatively stable across runs
218(their standard deviation is relatively low) compared to the prefetch misses.
219We can conclude from this information that LLC load and store misses can be
220accounted for quite precisely, but prefetches within a function seems to behave
221too erratically (not much causality link between the code executed and the CPU
222prefetch activity) to be accounted for.
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223
224.B OPTIONS:
225
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226.TP
227.BR "\-h, \-\-help"
228Show summary of possible options and commands.
229.TP
230.BR "\-k, \-\-kernel"
231Apply for the kernel tracer
232.TP
233.BR "\-u, \-\-userspace"
234Apply for the user-space tracer
235.TP
236.BR "\-\-function"
237Dynamic function entry/return probe (default)
238.RE
239.PP
6991b181 240
ee2758e5 241.PP
feb3ca56 242\fBcreate\fP [NAME] [OPTIONS]
ee2758e5 243.RS
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244Create tracing session.
245
246A tracing session contains channel(s) which contains event(s). It is domain
e256d661 247agnostic, meaning that channels and events can be enabled for the
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248user-space tracer and/or the kernel tracer. It acts like a container
249aggregating multiple tracing sources.
250
251On creation, a \fB.lttngrc\fP file is created in your $HOME directory
252containing the current session name. If NAME is omitted, a session name is
fa072eae 253automatically created having this form: 'auto-yyyymmdd-hhmmss'.
6991b181 254
c9e32613 255If no \fB\-o, \-\-output\fP is specified, the traces will be written in
6991b181 256$HOME/lttng-traces.
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257
258The $HOME environment variable can be overridden by defining the environment
259variable LTTNG_HOME. This is useful when the user running the commands has
260a non-writeable home directory.
6991b181 261
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262The session name MUST NOT contain the character '/'.
263
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264.B OPTIONS:
265
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266.TP
267.BR "\-h, \-\-help"
268Show summary of possible options and commands.
269.TP
270.BR "\-\-list-options"
271Simple listing of options
272.TP
273.BR "\-o, \-\-output PATH"
274Specify output path for traces
275.TP
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276.BR "\-\-no-output"
277Traces will not be output
278.TP
ee2758e5 279.BR "\-\-snapshot"
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280Set the session in snapshot mode. Created in no-output mode and uses the
281URL, if one is specified, as the default snapshot output. Every channel will be set
ee2758e5 282in overwrite mode and with mmap output (splice not supported).
0794f51b 283.TP
d73c5802 284.BR "\-\-live [USEC]"
eb82f91d 285Set the session exclusively in live mode. The parameter is the delay in micro
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286seconds before the data is flushed and streamed. The live mode allows you to
287stream the trace and view it while it's being recorded by any tracer. For that,
288you need a lttng-relayd and this session requires a network URL (\-U or
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289\-C/\-D). If no USEC nor URL is provided, the default is to use a timer value
290set to 1000000 and the network URL set to net://127.0.0.1.
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291
292To read a live session, you can use babeltrace(1) or the live streaming
293protocol in doc/live-reading-protocol.txt. Here is an example:
294
295.nf
296$ lttng-relayd -o /tmp/lttng
297$ lttng create --live 200000 -U net://localhost
298$ lttng enable-event -a --userspace
299$ lttng start
300.fi
301
302After the start, you'll be able to read the events while they are being
303recorded in /tmp/lttng.
6b8f2e64 304
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305.TP
306.BR "\-\-shm-path PATH"
307
308Path where shared memory holding buffers should be created. Useful
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309when used with PRAMFS or other persistent memory filesystems to extract
310trace data in the event of a crash requiring a reboot.
d7ba1388 311
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312.TP
313.BR "\-U, \-\-set-url=URL"
314Set URL for the consumer output destination. It is persistent for the
315session lifetime. Redo the command to change it. This will set both data
316and control URL for network.
317.TP
318.BR "\-C, \-\-ctrl-url=URL"
319Set control path URL. (Must use -D also)
320.TP
321.BR "\-D, \-\-data-url=URL"
322Set data path URL. (Must use -C also)
323.PP
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324Using these options, each API call can be controlled individually. For
325instance, \-C does not enable the consumer automatically. You'll need the \-e
326option for that.
327
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328.B URL FORMAT:
329
330proto://[HOST|IP][:PORT1[:PORT2]][/TRACE_PATH]
331
332Supported protocols are (proto):
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333.TP
334.BR "file://..."
335Local filesystem full path.
785d2d0d 336
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337.TP
338.BR "net://..."
339This will use the default network transport layer which is TCP for both
340control (PORT1) and data port (PORT2). The default ports are
341respectively 5342 and 5343. Note that net[6]:// is not yet supported.
785d2d0d 342
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343.TP
344.BR "tcp[6]://..."
345Can only be used with -C and -D together
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346
347NOTE: IPv6 address MUST be enclosed in brackets '[]' (rfc2732)
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348
349.B EXAMPLES:
350
ee2758e5 351.nf
6b8f2e64 352# lttng create -U net://192.168.1.42
ee2758e5 353.fi
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354Uses TCP and default ports for the given destination.
355
ee2758e5 356.nf
6b8f2e64 357# lttng create -U net6://[fe80::f66d:4ff:fe53:d220]
ee2758e5 358.fi
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359Uses TCP, default ports and IPv6.
360
ee2758e5 361.nf
6b8f2e64 362# lttng create s1 -U net://myhost.com:3229
6991b181 363.fi
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364Create session s1 and set its consumer to myhost.com on port 3229 for control.
365.RE
366.PP
6991b181 367
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368.PP
369\fBdestroy\fP [NAME] [OPTIONS]
370.RS
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371Teardown tracing session
372
373Free memory on the session daemon and tracer side. It's gone!
374
375If NAME is omitted, the session name is taken from the .lttngrc file.
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376
377.B OPTIONS:
378
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379.TP
380.BR "\-h, \-\-help"
381Show summary of possible options and commands.
382.TP
383.BR "\-a, \-\-all"
384Destroy all sessions
385.TP
386.BR "\-\-list-options"
387Simple listing of options
388.RE
389.PP
6991b181 390
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391.PP
392\fBenable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
393.RS
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394Enable tracing channel
395
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396To enable an event, you must enable both the event and the channel that
397contains it.
b883c01b 398
c9e32613 399If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
6991b181 400file.
7972aab2 401
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402Exactly one of \-k or -u must be specified.
403
7972aab2 404It is important to note that if a certain type of buffers is used, the session
bd337b98 405will be set with that type and all other subsequent channel needs to have the
7972aab2 406same type.
bd337b98 407
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408Note that once the session has been started and enabled on the tracer side,
409it's not possible anymore to enable a new channel for that session.
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410
411.B OPTIONS:
412
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413.TP
414.BR "\-h, \-\-help"
415Show this help
416.TP
417.BR "\-\-list-options"
418Simple listing of options
419.TP
420.BR "\-s, \-\-session NAME"
421Apply on session name
422.TP
423.BR "\-k, \-\-kernel"
424Apply to the kernel tracer
425.TP
426.BR "\-u, \-\-userspace"
427Apply to the user-space tracer
428.TP
429.BR "\-\-discard"
430Discard event when subbuffers are full (default)
431.TP
432.BR "\-\-overwrite"
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433Flight recorder mode: overwrites events when subbuffers are full. The
434number of subbuffer must be 2 or more.
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435.TP
436.BR "\-\-subbuf-size SIZE"
437Subbuffer size in bytes {+k,+M,+G}.
438(default UST uid: 131072, UST pid: 4096, kernel: 262144, metadata: 4096)
439Rounded up to the next power of 2.
440
441The minimum subbuffer size, for each tracer, is the max value between
442the default above and the system page size. You can issue this command
443to get the current page size on your system: \fB$ getconf PAGE_SIZE\fP
444.TP
445.BR "\-\-num-subbuf NUM"
446Number of subbuffers. (default UST uid: 4, UST pid: 4, kernel: 4,
447metadata: 2) Rounded up to the next power of 2.
448.TP
449.BR "\-\-switch-timer USEC"
450Switch subbuffer timer interval in µsec.
451(default UST uid: 0, UST pid: 0, kernel: 0, metadata: 0)
452.TP
453.BR "\-\-read-timer USEC"
454Read timer interval in µsec.
455(default UST uid: 0, UST pid: 0, kernel: 200000, metadata: 0)
456.TP
457.BR "\-\-output TYPE"
458Channel output type. Possible values: mmap, splice
459(default UST uid: mmap, UST pid: mmap, kernel: splice, metadata: mmap)
460.TP
461.BR "\-\-buffers-uid"
462Use per UID buffer (\-u only). Buffers are shared between applications
463that have the same UID.
464.TP
465.BR "\-\-buffers-pid"
466Use per PID buffer (\-u only). Each application has its own buffers.
467.TP
468.BR "\-\-buffers-global"
469Use shared buffer for the whole system (\-k only)
470.TP
471.BR "\-C, \-\-tracefile-size SIZE"
472Maximum size of each tracefile within a stream (in bytes).
4730 means unlimited. (default: 0)
c0684a0d 474Note: traces generated with this option may inaccurately report
a10f04ad 475discarded events as of CTF 1.8.
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476.TP
477.BR "\-W, \-\-tracefile-count COUNT"
478Used in conjunction with \-C option, this will limit the number of files
479created to the specified count. 0 means unlimited. (default: 0)
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480
481.B EXAMPLES:
482
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483.nf
484$ lttng enable-channel -k -C 4096 -W 32 chan1
485.fi
e256d661 486For each stream, the maximum size of each trace file will be 4096 bytes and
cea28771 487there will be a maximum of 32 different files. The file count is appended after
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488the stream number as seen in the following example. The last trace file is
489smaller than 4096 since it was not completely filled.
490
05be3802 491.nf
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492 ~/lttng-traces/[...]/chan1_0_0 (4096)
493 ~/lttng-traces/[...]/chan1_0_1 (4096)
494 ~/lttng-traces/[...]/chan1_0_2 (3245)
495 ~/lttng-traces/[...]/chan1_1_0 (4096)
496 ...
05be3802 497.fi
1624d5b7 498
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499.nf
500$ lttng enable-channel -k -C 4096
501.fi
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502This will create trace files of 4096 bytes and will create new ones as long as
503there is data available.
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504.RE
505.PP
6991b181 506
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507.PP
508\fBenable-event\fP NAME[,NAME2,...] [-k|-u] [OPTIONS]
509.RS
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510Enable tracing event
511
c9e32613 512A tracing event is always assigned to a channel. If \fB\-c, \-\-channel\fP is
6991b181 513omitted, a default channel named '\fBchannel0\fP' is created and the event is
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514added to it. If \fB\-c, \-\-channel\fP is omitted, but a non-default
515channel already exists within the session, an error is returned. For the
516user-space tracer, using \fB\-a, \-\-all\fP is the same as using the
517wildcard "*".
6991b181 518
c9e32613 519If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
6991b181 520file.
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521
522.B OPTIONS:
523
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524.TP
525.BR "\-h, \-\-help"
526Show summary of possible options and commands.
527.TP
528.BR "\-\-list-options"
529Simple listing of options
530.TP
531.BR "\-s, \-\-session NAME"
532Apply on session name
533.TP
534.BR "\-c, \-\-channel NAME"
535Apply on channel name
536.TP
537.BR "\-a, \-\-all"
e256d661 538Enable all tracepoints and syscalls. This actually enables a single
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539wildcard event "*".
540.TP
541.BR "\-k, \-\-kernel"
542Apply for the kernel tracer
543.TP
544.BR "\-u, \-\-userspace"
545Apply for the user-space tracer
546.TP
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547.BR "\-j, \-\-jul"
548Apply for Java application using Java Util Logging interface (JUL)
549.TP
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550.BR "\-l, \-\-log4j"
551Apply for Java application using LOG4J
552.TP
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553.BR "\-p, \-\-python"
554Apply for Python application using the logging module.
555.TP
6a240cd9 556.BR "\-\-tracepoint"
e256d661 557Tracepoint event (default). Userspace tracer supports wildcards at the end
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558of string. Don't forget to quote to deal with bash expansion.
559e.g.:
6991b181 560.nf
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561 "*"
562 "app_component:na*"
6991b181 563.fi
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564.TP
565.BR "\-\-loglevel NAME"
566Tracepoint loglevel range from 0 to loglevel. Listed in the help (\-h).
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567For the JUL domain, the loglevel ranges are detailed with the \-\-help
568option thus starting from SEVERE to FINEST.
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569For the LOG4J domain, loglevels range from FATAL to TRACE which are also
570detailed in the help.
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571For the Python domain, loglevels range from CRITICAL to DEBUG which are
572detailed in the help as well.
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573.TP
574.BR "\-\-loglevel-only NAME"
575Tracepoint loglevel (only this loglevel).
576The loglevel or loglevel-only options should be combined with a
577tracepoint name or tracepoint wildcard.
578.TP
579.BR "\-\-probe (addr | symbol | symbol+offset)"
580Dynamic probe. Addr and offset can be octal (0NNN...), decimal (NNN...)
581or hexadecimal (0xNNN...)
582.TP
583.BR "\-\-function (addr | symbol | symbol+offset)"
584Dynamic function entry/return probe. Addr and offset can be octal
585(0NNN...), decimal (NNN...) or hexadecimal (0xNNN...)
586.TP
587.BR "\-\-syscall"
588System call event. Enabling syscalls tracing (kernel tracer), you will
589not be able to disable them with disable-event. This is a known
627dbfd8
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590limitation. You can disable the entire channel to do the trick. Also note
591that per-syscall selection is not supported yet. Use with "-a" to enable
592all syscalls.
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593.TP
594.BR "\-\-filter 'expression'"
595Set a filter on a newly enabled event. Filter expression on event
e256d661
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596fields and context. The event will be recorded if the filter's
597expression evaluates to TRUE. Only specify on first activation of a
598given event within a session.
599Specifying a filter is only allowed when enabling events within a session before
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600tracing is started. If the filter fails to link with the event
601within the traced domain, the event will be discarded.
e256d661 602Filtering is currently only implemented for the user-space tracer.
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603
604Expression examples:
605
606.nf
607 'intfield > 500 && intfield < 503'
608 '(strfield == "test" || intfield != 10) && intfield > 33'
609 'doublefield > 1.1 && intfield < 5.3'
610.fi
611
612Wildcards are allowed at the end of strings:
613 'seqfield1 == "te*"'
614In string literals, the escape character is a '\\'. Use '\\*' for
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615the '*' character, and '\\\\' for the '\\' character sequence. Wildcard
616matches any sequence of characters, including an empty sub-string
617(matches 0 or more characters).
6a240cd9 618
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619Context information can be used for filtering. The examples below shows
620usage of context filtering on the process name (using a wildcard), process ID
621range, and unique thread ID. The process and thread IDs of
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622running applications can be found under columns "PID" and "LWP" of the
623"ps -eLf" command.
624
625.nf
626 '$ctx.procname == "demo*"'
627 '$ctx.vpid >= 4433 && $ctx.vpid < 4455'
628 '$ctx.vtid == 1234'
629.fi
630
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631Context information is available to all filters whether or not the add-context
632command has been used to add it to the event's channel, as long as the context
633field exists for that domain. For example, the filter examples given above will
634never fail to link: no add-context is required for the event's channel.
635
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636.TP
637.BR "\-x, \-\-exclude LIST"
638Add exclusions to UST tracepoints:
639Events that match any of the items in the comma-separated LIST are not
640enabled, even if they match a wildcard definition of the event.
641
642This option is also applicable with the \fB\-a, \-\-all\fP option,
643in which case all UST tracepoints are enabled except the ones whose
644names match any of the items in LIST.
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645.RE
646.PP
6991b181 647
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648.PP
649\fBdisable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
650.RS
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651Disable tracing channel
652
e256d661 653Disabling a channel disables the tracing of all of the channel's events. A channel
5368d366 654can be re-enabled by calling \fBlttng enable-channel NAME\fP again.
6991b181 655
c9e32613 656If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
6991b181 657file.
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658
659.B OPTIONS:
660
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661.TP
662.BR "\-h, \-\-help"
663Show summary of possible options and commands.
664.TP
665.BR "\-\-list-options"
666Simple listing of options
667.TP
668.BR "\-s, \-\-session NAME"
669Apply on session name
670.TP
671.BR "\-k, \-\-kernel"
672Apply for the kernel tracer
673.TP
674.BR "\-u, \-\-userspace"
675Apply for the user-space tracer
676.RE
677.PP
6991b181 678
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679.PP
680\fBdisable-event\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS]
681.RS
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682Disable tracing event
683
684The event, once disabled, can be re-enabled by calling \fBlttng enable-event
685NAME\fP again.
686
c9e32613 687If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
6991b181 688file.
6991b181 689
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690If \fB\-c, \-\-channel\fP is omitted, the default channel name is used.
691If \fB\-c, \-\-channel\fP is omitted, but a non-default channel already
692exists within the session, an error is returned.
693
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694.B OPTIONS:
695
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696.TP
697.BR "\-h, \-\-help"
698Show summary of possible options and commands.
699.TP
700.BR "\-\-list-options"
701Simple listing of options
702.TP
703.BR "\-s, \-\-session NAME"
704Apply on session name
705.TP
85076754
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706.BR "\-c, \-\-channel NAME"
707Apply on channel name
708.TP
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709.BR "\-a, \-\-all-events"
710Disable all events. This does NOT disable "*" but rather every known
711events of the session.
712.TP
713.BR "\-k, \-\-kernel"
714Apply for the kernel tracer
715.TP
716.BR "\-u, \-\-userspace"
717Apply for the user-space tracer
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718.TP
719.BR "\-j, \-\-jul"
720Apply for Java application using Java Util Logging interface (JUL)
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721.TP
722.BR "\-l, \-\-log4j"
723Apply for Java application using LOG4J
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724.TP
725.BR "\-p, \-\-python"
726Apply for Python application using the logging module.
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727.RE
728.PP
6991b181 729
747361fe
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730.PP
731\fBlist\fP [OPTIONS] [SESSION [SESSION OPTIONS]]
732.RS
c9e32613 733List tracing session information.
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734
735With no arguments, it will list available tracing session(s).
736
fa072eae
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737With the session name, it will display the details of the session including
738the trace file path, the associated channels and their state (activated
d829b38c 739and deactivated), the activated events and more.
fa072eae 740
c9e32613 741With \-k alone, it will list all available kernel events (except the system
6991b181 742calls events).
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743With \-j alone, the available JUL event from registered application will be
744list. The event corresponds to the Logger name in the Java JUL application.
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745With \-l alone, the available LOG4J event from registered application will be
746list. The event corresponds to the Logger name in the Java LOG4J application.
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747With \-p alone, the available Python event from registered application will be
748list. The event corresponds to the Logger name in the Python application.
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749With \-u alone, it will list all available user-space events from registered
750applications. Here is an example of 'lttng list \-u':
6991b181 751
747361fe 752.nf
6991b181
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753PID: 7448 - Name: /tmp/lttng-ust/tests/hello/.libs/lt-hello
754 ust_tests_hello:tptest_sighandler (type: tracepoint)
755 ust_tests_hello:tptest (type: tracepoint)
747361fe 756.fi
6991b181
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757
758You can now enable any event listed by using the name :
759\fBust_tests_hello:tptest\fP.
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760
761.B OPTIONS:
762
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763.TP
764.BR "\-h, \-\-help"
765Show summary of possible options and commands.
766.TP
767.BR "\-\-list-options"
768Simple listing of options
769.TP
770.BR "\-k, \-\-kernel"
771Select kernel domain
772.TP
773.BR "\-u, \-\-userspace"
774Select user-space domain.
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775.TP
776.BR "\-j, \-\-jul"
777Apply for Java application using JUL
778.TP
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779.BR "\-l, \-\-log4j"
780Apply for Java application using LOG4J
0e115563
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781.TP
782.BR "\-p, \-\-python"
783Apply for Python application using the logging module.
784.TP
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785.BR "\-f, \-\-fields"
786List event fields
6991b181 787
747361fe 788.PP
6b8f2e64
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789.B SESSION OPTIONS:
790
747361fe
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791.TP
792.BR "\-c, \-\-channel NAME"
793List details of a channel
794.TP
795.BR "\-d, \-\-domain"
796List available domain(s)
797.RE
798.PP
6991b181 799
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800.PP
801\fBload\fP [OPTIONS] [NAME]
802.RS
803Load tracing session configuration
804
805If NAME is omitted, all session configurations found in both the user's session
bd88d988 806configuration directory (default: ~/.lttng/sessions/) and the system session
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807configuration directory (default: /etc/lttng/sessions/) will be loaded. Note
808that the sessions in the user directory are loaded first and then the system
809wide directory are loaded.
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810
811.B OPTIONS:
812
813.TP
814.BR "\-h, \-\-help"
815Show summary of possible options and commands.
816.TP
817.BR "\-a, \-\-all"
818Load all session configurations (default).
819.TP
820.BR "\-i, \-\-input-path PATH"
bd88d988
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821Specify the input path for session configurations. This overrides the default
822session configuration directory.
516f6cbe
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823.TP
824.BR "\-f, -\-force"
825Overwrite current session configuration(s) if a session of the same name
826already exists.
827.RE
828.PP
829
830.PP
831\fBsave\fP [OPTIONS] [SESSION]
832.RS
833Save tracing session configuration
834
835If SESSION is omitted, all session configurations will be saved to individual
553067af 836\fB.lttng\fP files under the user's session configuration directory (default:
bd88d988
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837~/.lttng/sessions/). The default session configuration file naming scheme is
838\fBSESSION.lttng\fP.
516f6cbe 839
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840For instance, a user in the tracing group saving a session from a root session
841daemon will save it in her/his user directory.
842
516f6cbe
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843.B OPTIONS:
844
845.TP
846.BR "\-h, \-\-help"
847Show summary of possible options and commands.
848.TP
849.BR "\-a, \-\-all"
850Save all session configurations (default).
851.TP
852.BR "\-o, \-\-output-path PATH"
553067af
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853Specify the output path for saved sessions. This overrides the default session
854configuration directory.
516f6cbe
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855.TP
856.BR "\-f, -\-force"
857Overwrite session configuration file if session name clashes.
858.RE
859.PP
860
7c96a096
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861.PP
862\fBset-session\fP NAME [OPTIONS]
863.RS
6991b181
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864Set current session name
865
866Will change the session name in the .lttngrc file.
6991b181
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867
868.B OPTIONS:
869
7c96a096
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870.TP
871.BR "\-h, \-\-help"
872Show summary of possible options and commands.
873.TP
874.BR "\-\-list-options"
875Simple listing of options
876.RE
877.PP
6991b181 878
8df3bfe9
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879.PP
880\fBsnapshot\fP [OPTIONS] ACTION
881.RS
b872baea 882Snapshot command for LTTng session.
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883
884.B OPTIONS:
885
8df3bfe9
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886.TP
887.BR "\-h, \-\-help"
888Show summary of possible options and commands.
889.TP
890.BR "\-\-list-options"
891Simple listing of options
b872baea 892
8df3bfe9 893.PP
b872baea
DG
894.B ACTION:
895
8df3bfe9 896.TP
b872baea
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897\fBadd-output\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] <URL> | -C <URL> -D <URL>
898
88743287 899Setup and add a snapshot output for a session. Output is the destination
b872baea
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900where the snapshot will be sent. Only one output is permitted. To change it,
901you'll need to delete it and add back the new one.
902
8df3bfe9 903.TP
b872baea
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904\fBdel-output\fP ID | NAME [-s <NAME>]
905
88743287
JG
906Delete an output for a session using the output's ID. You can either specify the
907output by name or use its ID as returned by the list-output command.
b872baea 908
8df3bfe9 909.TP
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910\fBlist-output\fP [-s <NAME>]
911
912List the output of a session. Attributes of the output are printed.
913
8df3bfe9 914.TP
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915\fBrecord\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] [<URL> | -C <URL> -D <URL>]
916
917Snapshot a session's buffer(s) for all domains. If an URL is specified, it is
918used instead of a previously added output. Specifying only a name or/and a max
919size will override the current output values. For instance, you can record a
920snapshot with a custom maximum size or with a different name.
921
8df3bfe9 922.nf
1ac1098f 923$ lttng snapshot add-output -n mysnapshot file:///data/snapshot
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924[...]
925$ lttng snapshot record -n new_name_snapshot
8df3bfe9 926.fi
b872baea
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927
928The above will create a snapshot in /data/snapshot/new_name_snapshot* directory
929rather then in mysnapshot*/
b872baea 930
8df3bfe9
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931.PP
932.B DETAILED ACTION OPTIONS
b872baea 933
8df3bfe9
MD
934.TP
935.BR "\-s, \-\-session NAME"
936Apply to session name.
937.TP
938.BR "\-n, \-\-name NAME"
939Name of the snapshot's output.
940.TP
941.BR "\-m, \-\-max-size SIZE"
eb82f91d 942Maximum size in bytes of the snapshot. The maximum size does not include the
a8f307d8
SM
943metadata file. Human readable format is accepted: {+k,+M,+G}. For instance,
944\-\-max-size 5M
8df3bfe9
MD
945.TP
946.BR "\-C, \-\-ctrl-url URL"
947Set control path URL. (Must use -D also)
948.TP
949.BR "\-D, \-\-data-url URL"
950Set data path URL. (Must use -C also)
951.RE
952.PP
b872baea 953
afb8ca1b
MD
954.PP
955\fBstart\fP [NAME] [OPTIONS]
956.RS
6991b181
DG
957Start tracing
958
959It will start tracing for all tracers for a specific tracing session.
6991b181 960If NAME is omitted, the session name is taken from the .lttngrc file.
6991b181
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961
962.B OPTIONS:
963
afb8ca1b
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964.TP
965.BR "\-h, \-\-help"
966Show summary of possible options and commands.
967.TP
968.BR "\-\-list-options"
969Simple listing of options
970.RE
971.PP
6991b181 972
6c09bfdb
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973.PP
974\fBstop\fP [NAME] [OPTIONS]
975.RS
6991b181
DG
976Stop tracing
977
391b9c72
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978It will stop tracing for all tracers for a specific tracing session. Before
979returning, the command checks for data availability meaning that it will wait
980until the trace is readable for the session. Use \-\-no-wait to avoid this
981behavior.
6991b181
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982
983If NAME is omitted, the session name is taken from the .lttngrc file.
6991b181
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984
985.B OPTIONS:
986
6c09bfdb
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987.TP
988.BR "\-h, \-\-help"
989Show summary of possible options and commands.
990.TP
991.BR "\-\-list-options"
992Simple listing of options
3a7a166e
MJ
993.TP
994.BR "\-\-no-wait"
6c09bfdb
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995Don't wait for data availability.
996.RE
997.PP
6991b181 998
5975c30a
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999.PP
1000\fBversion\fP
1001.RS
6991b181 1002Show version information
6991b181
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1003
1004.B OPTIONS:
1005
5975c30a
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1006.TP
1007.BR "\-h, \-\-help"
1008Show summary of possible options and commands.
1009.TP
1010.BR "\-\-list-options"
1011Simple listing of options
1012.RE
1013.PP
6991b181 1014
5b4c1410
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1015.PP
1016\fBview\fP [SESSION_NAME] [OPTIONS]
1017.RS
1018View traces of a tracing session. By default, the babeltrace viewer
1019will be used for text viewing. If SESSION_NAME is omitted, the session
1020name is taken from the .lttngrc file.
6991b181
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1021
1022.B OPTIONS:
1023
5b4c1410
MD
1024.TP
1025.BR "\-h, \-\-help"
1026Show this help
1027.TP
1028.BR "\-\-list-options"
1029Simple listing of options
1030.TP
1031.BR "\-t, \-\-trace-path PATH"
1032Trace directory path for the viewer
1033.TP
1034.BR "\-e, \-\-viewer CMD"
1035Specify viewer and/or options to use This will completely override the
1036default viewers so please make sure to specify the full command. The
1037trace directory path of the session will be appended at the end to the
1038arguments
1039.RE
1040.PP
6991b181 1041
999ee001
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1042.SH "JUL/LOG4J DOMAIN"
1043
1044This section explains the JUL and LOG4J domain where JUL stands for Java Util
1045Logging. You can use these by using the \fBliblttng-ust-<domain>-jni.so\fP from
1046the lttng-ust(3) project.
acf47627
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1047
1048The LTTng Java Agent uses JNI to link the UST tracer to the Java application
1049that uses the agent. Thus, it behaves similarly to the UST domain (\-u). When
999ee001
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1050enabling events, you enable a Logger name that will then be mapped to a default
1051UST tracepoint called \fBlttng_jul:<domain>_event\fP in the
1052\fBlttng_<domain>_channel\fP. Using the lttng-ctl API, any JUL/LOG4J events
1053must use the tracepoint event type (same as \-\-tracepoint).
acf47627 1054
999ee001
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1055Because of the default immutable channel, the \fBenable-channel\fP command CAN
1056NOT be used with the JUL and LOG4J domain thus not having any options.
acf47627 1057
999ee001
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1058Also, loglevels are supported. Use \fBlttng enable-event \-h\fP to list them.
1059Wildcards are NOT supported except the "*" meaning all events (same as \-a).
acf47627
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1060
1061Exactly like the UST domain, if the Java application has the same UID as you,
1062you can trace it. Same goes for the tracing group accessing root applications.
1063
999ee001
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1064Finally, you can list every Logger name that are available from registered
1065applications to the session daemon by using \fBlttng list \-j\fP or \fB\-l\fP.
acf47627 1066
999ee001 1067Here is an example on how to use the JUL domain.
acf47627
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1068
1069.nf
1070$ lttng list -j
1071[...]
1072$ lttng create aSession
1073$ lttng enable-event -s aSession -j MyCustomLoggerName
1074$ lttng start
1075.fi
1076
1077More information can be found in the lttng-ust documentation, see
1078java-util-logging.txt
1079.PP
1080
c206d957 1081.SH "EXIT VALUES"
b107a0b1 1082.PP
6b8f2e64
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1083On success 0 is returned and a positive value on error. Value of 1 means a command
1084error, 2 an undefined command, 3 a fatal error and 4 a command warning meaning that
1085something went wrong during the command.
c206d957 1086
6b8f2e64 1087Any other value above 10, please refer to
b107a0b1 1088.BR "<lttng/lttng-error.h>"
6b8f2e64
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1089for a detailed list or use lttng_strerror() to get a human readable string of
1090the error code.
c206d957 1091.PP
b107a0b1 1092
6991b181
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1093.SH "ENVIRONMENT VARIABLES"
1094
1095.PP
1096Note that all command line options override environment variables.
1097.PP
1098
1099.PP
05833633 1100.IP "LTTNG_SESSIOND_PATH"
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1101Allows one to specify the full session daemon binary path to lttng command line
1102tool. You can also use \-\-sessiond-path option having the same effect.
b107a0b1
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1103.PP
1104
516f6cbe
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1105.PP
1106.IP "LTTNG_SESSION_CONFIG_XSD_PATH"
1107Set the path in which the \fBsession.xsd\fP session configuration schema may be
1108found.
1109.PP
1110
6991b181 1111.SH "SEE ALSO"
6b8f2e64
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1112.BR babeltrace(1),
1113.BR lttng-ust(3),
1114.BR lttng-sessiond(8),
1115.BR lttng-relayd(8),
b107a0b1 1116
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1117.SH "BUGS"
1118
b107a0b1 1119.PP
6991b181 1120If you encounter any issues or usability problem, please report it on our
6b8f2e64 1121mailing list <lttng-dev@lists.lttng.org> to help improve this project or
eb82f91d 1122at https://bugs.lttng.org which is a bug tracker.
b107a0b1
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1123.PP
1124
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1125.SH "CREDITS"
1126
1127.PP
c9e32613 1128lttng is distributed under the GNU General Public License version 2. See the file
6991b181
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1129COPYING for details.
1130.PP
1131A Web site is available at http://lttng.org for more information on the LTTng
1132project.
1133.PP
1134You can also find our git tree at http://git.lttng.org.
1135.PP
1136Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
1137.PP
1138You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
1139.PP
1140.SH "THANKS"
1141
1142.PP
1143Thanks to Yannick Brosseau without whom this project would never have been so
1144lean and mean! Also thanks to the Ericsson teams working on tracing which
fa072eae 1145helped us greatly with detailed bug reports and unusual test cases.
6991b181
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1146
1147Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
1148maintainer) and Jon Bernard for our Debian packages.
1149
1150Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
1151Montreal for the LTTng journey.
c9e32613 1152.PP
6991b181
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1153.SH "AUTHORS"
1154
1155.PP
1156lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
1157David Goulet. More people have since contributed to it. It is currently
9b22d135 1158maintained by Jérémie Galarneau <jeremie.galarneau@efficios.com>.
6991b181 1159.PP
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