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391b9c72 | 1 | .TH "LTTNG" "1" "December 3rd, 2012" "" "" |
6991b181 DG |
2 | |
3 | .SH "NAME" | |
c5db699c | 4 | lttng \(em LTTng 2.x tracer control command line tool |
6991b181 DG |
5 | |
6 | .SH "SYNOPSIS" | |
7 | ||
8 | .PP | |
9 | .nf | |
10 | lttng [OPTIONS] <COMMAND> | |
11 | .fi | |
12 | .SH "DESCRIPTION" | |
13 | ||
14 | .PP | |
15 | The LTTng project aims at providing highly efficient tracing tools for Linux. | |
16 | It's tracers help tracking down performance issues and debugging problems | |
17 | involving multiple concurrent processes and threads. Tracing across multiple | |
18 | systems is also possible. | |
19 | ||
fa072eae | 20 | The \fBlttng\fP command line tool from the lttng-tools package is used to control |
6991b181 DG |
21 | both kernel and user-space tracing. Every interactions with the tracer should |
22 | be done by this tool or by the liblttng-ctl provided with the lttng-tools | |
23 | package. | |
24 | ||
25 | LTTng uses a session daemon (lttng-sessiond(8)), acting as a tracing registry, | |
50a3b92a | 26 | which allows you to interact with multiple tracers (kernel and user-space) |
6991b181 DG |
27 | inside the same container, a tracing session. Traces can be gathered from the |
28 | kernel and/or instrumented applications (lttng-ust(3)). Aggregating and reading | |
29 | those traces is done using the babeltrace(1) text viewer. | |
30 | ||
50a3b92a DG |
31 | We introduce the notion of \fBtracing domains\fP which is essentially a type of |
32 | tracer (kernel or user space for now). In the future, we could see a third | |
33 | tracer being for instance an hypervisor. For some commands, you'll need to | |
34 | specify on which domain the command applies (-u or -k). For instance, enabling | |
35 | a kernel event, you must specify the kernel domain to the command so we know | |
36 | for which tracer this event is for. | |
37 | ||
6991b181 DG |
38 | In order to trace the kernel, the session daemon needs to be running as root. |
39 | LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is | |
40 | in that group can interact with the root session daemon and thus trace the | |
41 | kernel. Session daemons can co-exist meaning that you can have a session daemon | |
fa072eae YB |
42 | running as Alice that can be used to trace her applications along side with a |
43 | root daemon or even a Bob daemon. We highly recommend to start the session | |
6991b181 DG |
44 | daemon at boot time for stable and long term tracing. |
45 | ||
46 | Every user-space applications instrumented with lttng-ust(3), will | |
47 | automatically register to the session daemon. This feature gives you the | |
48 | ability to list available traceable applications and tracepoints on a per user | |
49 | basis. (See \fBlist\fP command). | |
50 | .SH "OPTIONS" | |
51 | ||
52 | .PP | |
53 | This program follow the usual GNU command line syntax with long options starting with | |
54 | two dashes. Below is a summary of the available options. | |
55 | .PP | |
56 | ||
57 | .TP | |
c9e32613 | 58 | .BR "\-h, \-\-help" |
6991b181 DG |
59 | Show summary of possible options and commands. |
60 | .TP | |
c9e32613 | 61 | .BR "\-v, \-\-verbose" |
6991b181 | 62 | Increase verbosity. |
d829b38c | 63 | Three levels of verbosity are available which are triggered by putting additional v to |
fa072eae | 64 | the option (\-vv or \-vvv) |
6991b181 | 65 | .TP |
c9e32613 | 66 | .BR "\-q, \-\-quiet" |
6991b181 DG |
67 | Suppress all messages (even errors). |
68 | .TP | |
c9e32613 | 69 | .BR "\-g, \-\-group NAME" |
6991b181 DG |
70 | Set unix tracing group name. (default: tracing) |
71 | .TP | |
c9e32613 | 72 | .BR "\-n, \-\-no-sessiond" |
6991b181 DG |
73 | Don't automatically spawn a session daemon. |
74 | .TP | |
391b9c72 | 75 | .BR "\-\-sessiond\-path PATH" |
6991b181 DG |
76 | Set session daemon full binary path. |
77 | .TP | |
c9e32613 | 78 | .BR "\-\-list\-options" |
6991b181 DG |
79 | Simple listing of lttng options. |
80 | .TP | |
c9e32613 | 81 | .BR "\-\-list\-commands" |
6991b181 DG |
82 | Simple listing of lttng commands. |
83 | .SH "COMMANDS" | |
84 | ||
812a5eb7 | 85 | .PP |
ee2758e5 | 86 | \fBadd-context\fP [OPTIONS] |
812a5eb7 | 87 | .RS |
6991b181 DG |
88 | Add context to event(s) and/or channel(s). |
89 | ||
391b9c72 DG |
90 | A context is basically extra information appended to a channel. For instance, |
91 | you could ask the tracer to add the PID information for all events in a | |
92 | channel. You can also add performance monitoring unit counters (perf PMU) using | |
93 | the perf kernel API). | |
6991b181 DG |
94 | |
95 | For example, this command will add the context information 'prio' and two perf | |
96 | counters (hardware branch misses and cache misses), to all events in the trace | |
97 | data output: | |
98 | ||
812a5eb7 MD |
99 | .nf |
100 | # lttng add-context \-k \-t prio \-t perf:branch-misses \\ | |
101 | \-t perf:cache-misses | |
102 | .fi | |
6991b181 | 103 | |
c9e32613 | 104 | Please take a look at the help (\-h/\-\-help) for a detailed list of available |
6991b181 DG |
105 | contexts. |
106 | ||
bd337b98 DG |
107 | If no channel is given (\-c), the context is added to all channels that were |
108 | already enabled. If the session has no channel, a default channel is created. | |
109 | Otherwise the context will be added only to the given channel (\-c). | |
6991b181 | 110 | |
c9e32613 | 111 | If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc |
6991b181 | 112 | file. |
6991b181 DG |
113 | |
114 | .B OPTIONS: | |
115 | ||
812a5eb7 MD |
116 | .TP |
117 | .BR "\-h, \-\-help" | |
118 | Show summary of possible options and commands. | |
119 | .TP | |
120 | .BR "\-s, \-\-session NAME" | |
121 | Apply on session name. | |
122 | .TP | |
123 | .BR "\-c, \-\-channel NAME" | |
124 | Apply on channel name. | |
125 | .TP | |
126 | .BR "\-k, \-\-kernel" | |
127 | Apply for the kernel tracer | |
128 | .TP | |
129 | .BR "\-u, \-\-userspace" | |
130 | Apply for the user-space tracer | |
131 | .TP | |
132 | .BR "\-t, \-\-type TYPE" | |
133 | Context type. You can repeat this option on the command line. Please | |
134 | use "lttng add-context \-h" to list all available types. | |
135 | .RE | |
136 | .PP | |
6991b181 | 137 | |
22019883 MD |
138 | .PP |
139 | \fBcalibrate\fP [OPTIONS] | |
140 | .RS | |
6991b181 DG |
141 | Quantify LTTng overhead |
142 | ||
143 | The LTTng calibrate command can be used to find out the combined average | |
144 | overhead of the LTTng tracer and the instrumentation mechanisms used. This | |
145 | overhead can be calibrated in terms of time or using any of the PMU performance | |
146 | counter available on the system. | |
147 | ||
148 | For now, the only calibration implemented is that of the kernel function | |
149 | instrumentation (kretprobes). | |
150 | ||
151 | * Calibrate kernel function instrumentation | |
152 | ||
153 | Let's use an example to show this calibration. We use an i7 processor with 4 | |
154 | general-purpose PMU registers. This information is available by issuing dmesg, | |
155 | looking for "generic registers". | |
156 | ||
157 | This sequence of commands will gather a trace executing a kretprobe hooked on | |
158 | an empty function, gathering PMU counters LLC (Last Level Cache) misses | |
c9e32613 | 159 | information (see lttng add-context \-\-help to see the list of available PMU |
6991b181 DG |
160 | counters). |
161 | ||
22019883 | 162 | .nf |
6991b181 | 163 | # lttng create calibrate-function |
22019883 MD |
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 | |
6991b181 DG |
169 | # lttng start |
170 | # for a in $(seq 1 10); do \\ | |
c9e32613 | 171 | lttng calibrate \-\-kernel \-\-function; |
6991b181 DG |
172 | done |
173 | # lttng destroy | |
22019883 MD |
174 | # babeltrace $(ls \-1drt ~/lttng-traces/calibrate-function-* \\ |
175 | | tail \-n 1) | |
176 | .fi | |
6991b181 DG |
177 | |
178 | The output from babeltrace can be saved to a text file and opened in a | |
179 | spreadsheet (e.g. oocalc) to focus on the per-PMU counter delta between | |
180 | consecutive "calibrate_entry" and "calibrate_return" events. Note that these | |
181 | counters are per-CPU, so scheduling events would need to be present to account | |
182 | for migration between CPU. Therefore, for calibration purposes, only events | |
183 | staying on the same CPU must be considered. | |
184 | ||
185 | The average result, for the i7, on 10 samples: | |
186 | ||
22019883 | 187 | .nf |
6991b181 DG |
188 | Average Std.Dev. |
189 | perf_LLC_load_misses: 5.0 0.577 | |
190 | perf_LLC_store_misses: 1.6 0.516 | |
191 | perf_LLC_prefetch_misses: 9.0 14.742 | |
22019883 | 192 | .fi |
6991b181 DG |
193 | |
194 | As 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. | |
196 | We can conclude from this information that LLC load and store misses can be | |
197 | accounted for quite precisely, but prefetches within a function seems to behave | |
198 | too erratically (not much causality link between the code executed and the CPU | |
199 | prefetch activity) to be accounted for. | |
6991b181 DG |
200 | |
201 | .B OPTIONS: | |
202 | ||
22019883 MD |
203 | .TP |
204 | .BR "\-h, \-\-help" | |
205 | Show summary of possible options and commands. | |
206 | .TP | |
207 | .BR "\-k, \-\-kernel" | |
208 | Apply for the kernel tracer | |
209 | .TP | |
210 | .BR "\-u, \-\-userspace" | |
211 | Apply for the user-space tracer | |
212 | .TP | |
213 | .BR "\-\-function" | |
214 | Dynamic function entry/return probe (default) | |
215 | .RE | |
216 | .PP | |
6991b181 | 217 | |
ee2758e5 MD |
218 | .PP |
219 | .IP \fBcreate\fP [NAME] [OPTIONS] | |
220 | .RS | |
6991b181 DG |
221 | Create tracing session. |
222 | ||
223 | A tracing session contains channel(s) which contains event(s). It is domain | |
224 | agnostic meaning that you can enable channels and events for either the | |
225 | user-space tracer and/or the kernel tracer. It acts like a container | |
226 | aggregating multiple tracing sources. | |
227 | ||
228 | On creation, a \fB.lttngrc\fP file is created in your $HOME directory | |
229 | containing the current session name. If NAME is omitted, a session name is | |
fa072eae | 230 | automatically created having this form: 'auto-yyyymmdd-hhmmss'. |
6991b181 | 231 | |
c9e32613 | 232 | If no \fB\-o, \-\-output\fP is specified, the traces will be written in |
6991b181 | 233 | $HOME/lttng-traces. |
feb0f3e5 AM |
234 | |
235 | The $HOME environment variable can be overridden by defining the environment | |
236 | variable LTTNG_HOME. This is useful when the user running the commands has | |
237 | a non-writeable home directory. | |
6991b181 DG |
238 | |
239 | .B OPTIONS: | |
240 | ||
ee2758e5 MD |
241 | .TP |
242 | .BR "\-h, \-\-help" | |
243 | Show summary of possible options and commands. | |
244 | .TP | |
245 | .BR "\-\-list-options" | |
246 | Simple listing of options | |
247 | .TP | |
248 | .BR "\-o, \-\-output PATH" | |
249 | Specify output path for traces | |
250 | .TP | |
251 | .BR "\-\-no-output" | |
252 | Traces will not be outputed | |
253 | .TP | |
254 | .BR "\-\-snapshot" | |
255 | Set the session in snapshot mode. Created in no-output mode and uses the | |
256 | URL, if one, as the default snapshot output. Every channel will be set | |
257 | in overwrite mode and with mmap output (splice not supported). | |
6b8f2e64 | 258 | |
ee2758e5 MD |
259 | .TP |
260 | .BR "\-U, \-\-set-url=URL" | |
261 | Set URL for the consumer output destination. It is persistent for the | |
262 | session lifetime. Redo the command to change it. This will set both data | |
263 | and control URL for network. | |
264 | .TP | |
265 | .BR "\-C, \-\-ctrl-url=URL" | |
266 | Set control path URL. (Must use -D also) | |
267 | .TP | |
268 | .BR "\-D, \-\-data-url=URL" | |
269 | Set data path URL. (Must use -C also) | |
270 | .PP | |
6b8f2e64 DG |
271 | Using these options, each API call can be controlled individually. For |
272 | instance, \-C does not enable the consumer automatically. You'll need the \-e | |
273 | option for that. | |
274 | ||
785d2d0d DG |
275 | .B URL FORMAT: |
276 | ||
277 | proto://[HOST|IP][:PORT1[:PORT2]][/TRACE_PATH] | |
278 | ||
279 | Supported protocols are (proto): | |
ee2758e5 MD |
280 | .TP |
281 | .BR "file://..." | |
282 | Local filesystem full path. | |
785d2d0d | 283 | |
ee2758e5 MD |
284 | .TP |
285 | .BR "net://..." | |
286 | This will use the default network transport layer which is TCP for both | |
287 | control (PORT1) and data port (PORT2). The default ports are | |
288 | respectively 5342 and 5343. Note that net[6]:// is not yet supported. | |
785d2d0d | 289 | |
ee2758e5 MD |
290 | .TP |
291 | .BR "tcp[6]://..." | |
292 | Can only be used with -C and -D together | |
785d2d0d DG |
293 | |
294 | NOTE: IPv6 address MUST be enclosed in brackets '[]' (rfc2732) | |
6b8f2e64 DG |
295 | |
296 | .B EXAMPLES: | |
297 | ||
ee2758e5 | 298 | .nf |
6b8f2e64 | 299 | # lttng create -U net://192.168.1.42 |
ee2758e5 | 300 | .fi |
6b8f2e64 DG |
301 | Uses 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 |
6b8f2e64 DG |
306 | Uses TCP, default ports and IPv6. |
307 | ||
ee2758e5 | 308 | .nf |
6b8f2e64 | 309 | # lttng create s1 -U net://myhost.com:3229 |
6991b181 | 310 | .fi |
ee2758e5 MD |
311 | Create session s1 and set its consumer to myhost.com on port 3229 for control. |
312 | .RE | |
313 | .PP | |
6991b181 | 314 | |
f2b14ef1 MD |
315 | .PP |
316 | \fBdestroy\fP [NAME] [OPTIONS] | |
317 | .RS | |
6991b181 DG |
318 | Teardown tracing session |
319 | ||
320 | Free memory on the session daemon and tracer side. It's gone! | |
321 | ||
322 | If NAME is omitted, the session name is taken from the .lttngrc file. | |
6991b181 DG |
323 | |
324 | .B OPTIONS: | |
325 | ||
f2b14ef1 MD |
326 | .TP |
327 | .BR "\-h, \-\-help" | |
328 | Show summary of possible options and commands. | |
329 | .TP | |
330 | .BR "\-a, \-\-all" | |
331 | Destroy all sessions | |
332 | .TP | |
333 | .BR "\-\-list-options" | |
334 | Simple listing of options | |
335 | .RE | |
336 | .PP | |
6991b181 | 337 | |
05be3802 MD |
338 | .PP |
339 | \fBenable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS] | |
340 | .RS | |
6991b181 DG |
341 | Enable tracing channel |
342 | ||
004f3466 DG |
343 | To enable an event, you must enable both the event and the channel that |
344 | contains it. | |
b883c01b | 345 | |
c9e32613 | 346 | If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc |
6991b181 | 347 | file. |
7972aab2 | 348 | |
05be3802 MD |
349 | Exactly one of \-k or -u must be specified. |
350 | ||
7972aab2 | 351 | It is important to note that if a certain type of buffers is used, the session |
bd337b98 | 352 | will be set with that type and all other subsequent channel needs to have the |
7972aab2 | 353 | same type. |
bd337b98 | 354 | |
d2f11c4a DG |
355 | Note that once the session has been started and enabled on the tracer side, |
356 | it's not possible anymore to enable a new channel for that session. | |
6991b181 DG |
357 | |
358 | .B OPTIONS: | |
359 | ||
05be3802 MD |
360 | .TP |
361 | .BR "\-h, \-\-help" | |
362 | Show this help | |
363 | .TP | |
364 | .BR "\-\-list-options" | |
365 | Simple listing of options | |
366 | .TP | |
367 | .BR "\-s, \-\-session NAME" | |
368 | Apply on session name | |
369 | .TP | |
370 | .BR "\-k, \-\-kernel" | |
371 | Apply to the kernel tracer | |
372 | .TP | |
373 | .BR "\-u, \-\-userspace" | |
374 | Apply to the user-space tracer | |
375 | .TP | |
376 | .BR "\-\-discard" | |
377 | Discard event when subbuffers are full (default) | |
378 | .TP | |
379 | .BR "\-\-overwrite" | |
380 | Flight recorder mode : overwrites events when subbuffers are full | |
381 | .TP | |
382 | .BR "\-\-subbuf-size SIZE" | |
383 | Subbuffer size in bytes {+k,+M,+G}. | |
384 | (default UST uid: 131072, UST pid: 4096, kernel: 262144, metadata: 4096) | |
385 | Rounded up to the next power of 2. | |
386 | ||
387 | The minimum subbuffer size, for each tracer, is the max value between | |
388 | the default above and the system page size. You can issue this command | |
389 | to get the current page size on your system: \fB$ getconf PAGE_SIZE\fP | |
390 | .TP | |
391 | .BR "\-\-num-subbuf NUM" | |
392 | Number of subbuffers. (default UST uid: 4, UST pid: 4, kernel: 4, | |
393 | metadata: 2) Rounded up to the next power of 2. | |
394 | .TP | |
395 | .BR "\-\-switch-timer USEC" | |
396 | Switch subbuffer timer interval in µsec. | |
397 | (default UST uid: 0, UST pid: 0, kernel: 0, metadata: 0) | |
398 | .TP | |
399 | .BR "\-\-read-timer USEC" | |
400 | Read timer interval in µsec. | |
401 | (default UST uid: 0, UST pid: 0, kernel: 200000, metadata: 0) | |
402 | .TP | |
403 | .BR "\-\-output TYPE" | |
404 | Channel output type. Possible values: mmap, splice | |
405 | (default UST uid: mmap, UST pid: mmap, kernel: splice, metadata: mmap) | |
406 | .TP | |
407 | .BR "\-\-buffers-uid" | |
408 | Use per UID buffer (\-u only). Buffers are shared between applications | |
409 | that have the same UID. | |
410 | .TP | |
411 | .BR "\-\-buffers-pid" | |
412 | Use per PID buffer (\-u only). Each application has its own buffers. | |
413 | .TP | |
414 | .BR "\-\-buffers-global" | |
415 | Use shared buffer for the whole system (\-k only) | |
416 | .TP | |
417 | .BR "\-C, \-\-tracefile-size SIZE" | |
418 | Maximum size of each tracefile within a stream (in bytes). | |
419 | 0 means unlimited. (default: 0) | |
420 | .TP | |
421 | .BR "\-W, \-\-tracefile-count COUNT" | |
422 | Used in conjunction with \-C option, this will limit the number of files | |
423 | created to the specified count. 0 means unlimited. (default: 0) | |
1624d5b7 JD |
424 | |
425 | .B EXAMPLES: | |
426 | ||
05be3802 MD |
427 | .nf |
428 | $ lttng enable-channel -k -C 4096 -W 32 chan1 | |
429 | .fi | |
cea28771 DG |
430 | For each stream, the maximum size of each trace file will be 4096 bytes, and |
431 | there will be a maximum of 32 different files. The file count is appended after | |
1624d5b7 JD |
432 | the stream number as seen in the following example. The last trace file is |
433 | smaller than 4096 since it was not completely filled. | |
434 | ||
05be3802 | 435 | .nf |
1624d5b7 JD |
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 | |
05be3802 MD |
443 | .nf |
444 | $ lttng enable-channel -k -C 4096 | |
445 | .fi | |
1624d5b7 JD |
446 | This will create trace files of 4096 bytes and will create new ones as long as |
447 | there is data available. | |
05be3802 MD |
448 | .RE |
449 | .PP | |
6991b181 DG |
450 | |
451 | .IP "\fBenable-event\fP NAME[,NAME2,...] [-k|-u] [OPTIONS]" | |
452 | .nf | |
453 | Enable tracing event | |
454 | ||
c9e32613 | 455 | A tracing event is always assigned to a channel. If \fB\-c, \-\-channel\fP is |
6991b181 | 456 | omitted, a default channel named '\fBchannel0\fP' is created and the event is |
c9e32613 | 457 | added to it. For the user-space tracer, using \fB\-a, \-\-all\fP is the same as |
6991b181 DG |
458 | using the wildcard "*". |
459 | ||
c9e32613 | 460 | If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc |
6991b181 DG |
461 | file. |
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 |
c5650942 DG |
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 |
6991b181 DG |
481 | Apply for the user-space tracer |
482 | ||
c9e32613 | 483 | \-\-tracepoint |
6991b181 DG |
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*" | |
391b9c72 DG |
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] |
6991b181 DG |
498 | Dynamic probe. Addr and offset can be octal (0NNN...), decimal (NNN...) |
499 | or hexadecimal (0xNNN...) | |
c9e32613 | 500 | \-\-function [addr | symbol | symbol+offset] |
6991b181 DG |
501 | Dynamic function entry/return probe. Addr and offset can be octal |
502 | (0NNN...), decimal (NNN...) or hexadecimal (0xNNN...) | |
c9e32613 | 503 | \-\-syscall |
6b8f2e64 DG |
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 |
ee8ccafa MD |
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. | |
6b8f2e64 DG |
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 | |
ee8ccafa MD |
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' | |
6991b181 DG |
539 | .fi |
540 | ||
c9e32613 | 541 | .IP "\fBdisable-channel\fP NAME[,NAME2,...] [\-k|\-u] [OPTIONS]" |
6991b181 DG |
542 | .nf |
543 | Disable tracing channel | |
544 | ||
545 | Disabling a channel makes all event(s) in that channel to stop tracing. You can | |
546 | enable it back by calling \fBlttng enable-channel NAME\fP again. | |
547 | ||
c9e32613 | 548 | If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc |
6991b181 DG |
549 | file. |
550 | .fi | |
551 | ||
552 | .B OPTIONS: | |
553 | ||
6b8f2e64 DG |
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 |
6991b181 DG |
564 | Apply for the user-space tracer |
565 | .fi | |
566 | ||
c9e32613 | 567 | .IP "\fBdisable-event\fP NAME[,NAME2,...] [\-k|\-u] [OPTIONS]" |
6991b181 DG |
568 | .nf |
569 | Disable tracing event | |
570 | ||
571 | The event, once disabled, can be re-enabled by calling \fBlttng enable-event | |
572 | NAME\fP again. | |
573 | ||
c9e32613 | 574 | If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc |
6991b181 DG |
575 | file. |
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 |
c5650942 DG |
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 |
6991b181 DG |
593 | Apply for the user-space tracer |
594 | .fi | |
595 | ||
c9e32613 | 596 | .IP "\fBlist\fP [\-k|\-u] [SESSION [SESSION_OPTIONS]]" |
6991b181 | 597 | .nf |
c9e32613 | 598 | List tracing session information. |
6991b181 DG |
599 | |
600 | With no arguments, it will list available tracing session(s). | |
601 | ||
fa072eae YB |
602 | With the session name, it will display the details of the session including |
603 | the trace file path, the associated channels and their state (activated | |
d829b38c | 604 | and deactivated), the activated events and more. |
fa072eae | 605 | |
c9e32613 | 606 | With \-k alone, it will list all available kernel events (except the system |
6991b181 | 607 | calls events). |
c9e32613 DG |
608 | With \-u alone, it will list all available user-space events from registered |
609 | applications. Here is an example of 'lttng list \-u': | |
6991b181 DG |
610 | |
611 | PID: 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 | ||
615 | You 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 |
6991b181 DG |
629 | Select user-space domain. |
630 | ||
6b8f2e64 DG |
631 | .B SESSION OPTIONS: |
632 | ||
c9e32613 | 633 | \-c, \-\-channel NAME |
6991b181 | 634 | List details of a channel |
c9e32613 | 635 | \-d, \-\-domain |
6991b181 DG |
636 | List available domain(s) |
637 | .fi | |
638 | ||
639 | .IP "\fBset-session\fP NAME" | |
640 | .nf | |
641 | Set current session name | |
642 | ||
643 | Will 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 |
6991b181 DG |
652 | Simple listing of options |
653 | .fi | |
654 | ||
655 | .IP | |
656 | ||
b872baea DG |
657 | .IP "\fBsnapshot\fP ACTION" |
658 | .nf | |
659 | Snapshot 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 | ||
676 | Setup and add an snapshot output for a session. Output are the destination | |
677 | where the snapshot will be sent. Only one output is permitted. To change it, | |
678 | you'll need to delete it and add back the new one. | |
679 | ||
680 | \fBdel-output\fP ID | NAME [-s <NAME>] | |
681 | ||
682 | Delete an output for a session using the ID. You can either specify the | |
683 | output's ID that can be found with list-output or the name. | |
684 | ||
685 | \fBlist-output\fP [-s <NAME>] | |
686 | ||
687 | List 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 | ||
691 | Snapshot a session's buffer(s) for all domains. If an URL is specified, it is | |
692 | used instead of a previously added output. Specifying only a name or/and a max | |
693 | size will override the current output values. For instance, you can record a | |
694 | snapshot 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 | ||
700 | The above will create a snapshot in /data/snapshot/new_name_snapshot* directory | |
701 | rather then in mysnapshot*/ | |
702 | .fi | |
703 | ||
704 | .B LONG OPTIONS | |
705 | ||
706 | .nf | |
3ae6f666 DG |
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) | |
b872baea DG |
718 | .fi |
719 | ||
720 | .IP | |
721 | ||
6b8f2e64 | 722 | .IP "\fBstart\fP [NAME] [OPTIONS]" |
6991b181 DG |
723 | .nf |
724 | Start tracing | |
725 | ||
726 | It will start tracing for all tracers for a specific tracing session. | |
727 | ||
728 | If 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 |
6991b181 DG |
737 | Simple listing of options |
738 | .fi | |
739 | ||
740 | .IP | |
741 | ||
6b8f2e64 | 742 | .IP "\fBstop\fP [NAME] [OPTIONS]" |
6991b181 DG |
743 | .nf |
744 | Stop tracing | |
745 | ||
391b9c72 DG |
746 | It will stop tracing for all tracers for a specific tracing session. Before |
747 | returning, the command checks for data availability meaning that it will wait | |
748 | until the trace is readable for the session. Use \-\-no-wait to avoid this | |
749 | behavior. | |
6991b181 DG |
750 | |
751 | If 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 |
391b9c72 DG |
761 | \-\-no-wait |
762 | Don't wait for data availability. | |
6991b181 DG |
763 | .fi |
764 | ||
765 | .IP | |
766 | ||
767 | .IP "\fBversion\fP" | |
768 | .nf | |
769 | Show 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 |
6991b181 DG |
778 | Simple listing of options |
779 | .fi | |
780 | ||
781 | .IP | |
782 | ||
783 | .IP "\fBview\fP [SESSION_NAME] [OPTIONS]" | |
784 | .nf | |
785 | View traces of a tracing session | |
786 | ||
787 | By default, the babeltrace viewer will be used for text viewing. | |
788 | ||
fa072eae YB |
789 | If SESSION_NAME is omitted, the session name is taken from the .lttngrc file. |
790 | ||
6991b181 DG |
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 |
6991b181 DG |
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" |
6b8f2e64 DG |
811 | On success 0 is returned and a positive value on error. Value of 1 means a command |
812 | error, 2 an undefined command, 3 a fatal error and 4 a command warning meaning that | |
813 | something went wrong during the command. | |
c206d957 | 814 | |
6b8f2e64 DG |
815 | Any other value above 10, please refer to |
816 | .BR <lttng/lttng-error.h> | |
817 | for a detailed list or use lttng_strerror() to get a human readable string of | |
818 | the error code. | |
c206d957 | 819 | |
c206d957 | 820 | .PP |
6991b181 DG |
821 | .SH "ENVIRONMENT VARIABLES" |
822 | ||
823 | .PP | |
824 | Note that all command line options override environment variables. | |
825 | .PP | |
826 | ||
827 | .PP | |
05833633 | 828 | .IP "LTTNG_SESSIOND_PATH" |
c9e32613 DG |
829 | Allows one to specify the full session daemon binary path to lttng command line |
830 | tool. You can also use \-\-sessiond-path option having the same effect. | |
6991b181 | 831 | .SH "SEE ALSO" |
6b8f2e64 DG |
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) | |
6991b181 DG |
837 | .SH "BUGS" |
838 | ||
6991b181 | 839 | If you encounter any issues or usability problem, please report it on our |
6b8f2e64 DG |
840 | mailing list <lttng-dev@lists.lttng.org> to help improve this project or |
841 | at https://bugs.lttng.org which is a bugtracker. | |
6991b181 DG |
842 | .SH "CREDITS" |
843 | ||
844 | .PP | |
c9e32613 | 845 | lttng is distributed under the GNU General Public License version 2. See the file |
6991b181 DG |
846 | COPYING for details. |
847 | .PP | |
848 | A Web site is available at http://lttng.org for more information on the LTTng | |
849 | project. | |
850 | .PP | |
851 | You can also find our git tree at http://git.lttng.org. | |
852 | .PP | |
853 | Mailing lists for support and development: <lttng-dev@lists.lttng.org>. | |
854 | .PP | |
855 | You can find us on IRC server irc.oftc.net (OFTC) in #lttng. | |
856 | .PP | |
857 | .SH "THANKS" | |
858 | ||
859 | .PP | |
860 | Thanks to Yannick Brosseau without whom this project would never have been so | |
861 | lean and mean! Also thanks to the Ericsson teams working on tracing which | |
fa072eae | 862 | helped us greatly with detailed bug reports and unusual test cases. |
6991b181 DG |
863 | |
864 | Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA | |
865 | maintainer) and Jon Bernard for our Debian packages. | |
866 | ||
867 | Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de | |
868 | Montreal for the LTTng journey. | |
c9e32613 | 869 | .PP |
6991b181 DG |
870 | .SH "AUTHORS" |
871 | ||
872 | .PP | |
873 | lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and | |
874 | David Goulet. More people have since contributed to it. It is currently | |
875 | maintained by David Goulet <dgoulet@efficios.com>. | |
876 | .PP |