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278eefc8 | 1 | .TH "LTTNG" "1" "February 05th, 2014" "" "" |
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 | |
6991b181 | 9 | lttng [OPTIONS] <COMMAND> |
6991b181 DG |
10 | .SH "DESCRIPTION" |
11 | ||
12 | .PP | |
13 | The LTTng project aims at providing highly efficient tracing tools for Linux. | |
e256d661 | 14 | Its tracers help track down performance issues and debug problems |
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15 | involving multiple concurrent processes and threads. Tracing across multiple |
16 | systems is also possible. | |
17 | ||
fa072eae | 18 | The \fBlttng\fP command line tool from the lttng-tools package is used to control |
e256d661 JG |
19 | both kernel and user-space tracing. Every interaction with the tracer should |
20 | be done by this tool or by the liblttng-ctl library provided by the lttng-tools | |
6991b181 DG |
21 | package. |
22 | ||
23 | LTTng uses a session daemon (lttng-sessiond(8)), acting as a tracing registry, | |
50a3b92a | 24 | which allows you to interact with multiple tracers (kernel and user-space) |
6991b181 DG |
25 | inside the same container, a tracing session. Traces can be gathered from the |
26 | kernel and/or instrumented applications (lttng-ust(3)). Aggregating and reading | |
27 | those traces is done using the babeltrace(1) text viewer. | |
28 | ||
50a3b92a | 29 | We introduce the notion of \fBtracing domains\fP which is essentially a type of |
278eefc8 DG |
30 | tracer (kernel, user space or JUL for now). In the future, we could see more |
31 | tracer like for instance an hypervisor. For some commands, you'll need to | |
32 | specify on which domain the command operates (\-u, \-k or \-j). For instance, | |
33 | the kernel domain must be specified when enabling a kernel event. | |
50a3b92a | 34 | |
6991b181 DG |
35 | In order to trace the kernel, the session daemon needs to be running as root. |
36 | LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is | |
37 | in that group can interact with the root session daemon and thus trace the | |
e256d661 | 38 | kernel. Session daemons can co-exist, meaning that you can have a session daemon |
fa072eae | 39 | running as Alice that can be used to trace her applications along side with a |
e256d661 | 40 | root daemon or even a Bob daemon. We highly recommend starting the session |
6991b181 DG |
41 | daemon at boot time for stable and long term tracing. |
42 | ||
faf3c371 DG |
43 | Each user-space application instrumented with lttng-ust(3) will automatically |
44 | register with the root session daemon and its user session daemon. This allows | |
45 | each daemon to list the available traceable applications and tracepoints at any | |
46 | given moment (See the \fBlist\fP command). | |
6991b181 DG |
47 | .SH "OPTIONS" |
48 | ||
49 | .PP | |
50 | This program follow the usual GNU command line syntax with long options starting with | |
51 | two dashes. Below is a summary of the available options. | |
52 | .PP | |
53 | ||
54 | .TP | |
c9e32613 | 55 | .BR "\-h, \-\-help" |
6991b181 DG |
56 | Show summary of possible options and commands. |
57 | .TP | |
c9e32613 | 58 | .BR "\-v, \-\-verbose" |
6991b181 | 59 | Increase verbosity. |
d829b38c | 60 | Three levels of verbosity are available which are triggered by putting additional v to |
fa072eae | 61 | the option (\-vv or \-vvv) |
6991b181 | 62 | .TP |
c9e32613 | 63 | .BR "\-q, \-\-quiet" |
6991b181 DG |
64 | Suppress all messages (even errors). |
65 | .TP | |
c9e32613 | 66 | .BR "\-g, \-\-group NAME" |
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67 | Set unix tracing group name. (default: tracing) |
68 | .TP | |
c9e32613 | 69 | .BR "\-n, \-\-no-sessiond" |
6991b181 DG |
70 | Don't automatically spawn a session daemon. |
71 | .TP | |
391b9c72 | 72 | .BR "\-\-sessiond\-path PATH" |
6991b181 DG |
73 | Set session daemon full binary path. |
74 | .TP | |
c9e32613 | 75 | .BR "\-\-list\-options" |
6991b181 DG |
76 | Simple listing of lttng options. |
77 | .TP | |
c9e32613 | 78 | .BR "\-\-list\-commands" |
6991b181 DG |
79 | Simple listing of lttng commands. |
80 | .SH "COMMANDS" | |
81 | ||
812a5eb7 | 82 | .PP |
ee2758e5 | 83 | \fBadd-context\fP [OPTIONS] |
812a5eb7 | 84 | .RS |
6991b181 DG |
85 | Add context to event(s) and/or channel(s). |
86 | ||
391b9c72 DG |
87 | A context is basically extra information appended to a channel. For instance, |
88 | you could ask the tracer to add the PID information for all events in a | |
89 | channel. You can also add performance monitoring unit counters (perf PMU) using | |
90 | the perf kernel API). | |
6991b181 DG |
91 | |
92 | For example, this command will add the context information 'prio' and two perf | |
93 | counters (hardware branch misses and cache misses), to all events in the trace | |
94 | data output: | |
95 | ||
812a5eb7 MD |
96 | .nf |
97 | # lttng add-context \-k \-t prio \-t perf:branch-misses \\ | |
98 | \-t perf:cache-misses | |
99 | .fi | |
6991b181 | 100 | |
c9e32613 | 101 | Please take a look at the help (\-h/\-\-help) for a detailed list of available |
6991b181 DG |
102 | contexts. |
103 | ||
bd337b98 DG |
104 | If no channel is given (\-c), the context is added to all channels that were |
105 | already enabled. If the session has no channel, a default channel is created. | |
31ea4846 | 106 | Otherwise the context will be added only to the given channel (\-c). |
6991b181 | 107 | |
c9e32613 | 108 | If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc |
6991b181 | 109 | file. |
6991b181 DG |
110 | |
111 | .B OPTIONS: | |
112 | ||
812a5eb7 MD |
113 | .TP |
114 | .BR "\-h, \-\-help" | |
115 | Show summary of possible options and commands. | |
116 | .TP | |
117 | .BR "\-s, \-\-session NAME" | |
118 | Apply on session name. | |
119 | .TP | |
120 | .BR "\-c, \-\-channel NAME" | |
121 | Apply on channel name. | |
122 | .TP | |
123 | .BR "\-k, \-\-kernel" | |
124 | Apply for the kernel tracer | |
125 | .TP | |
126 | .BR "\-u, \-\-userspace" | |
127 | Apply for the user-space tracer | |
128 | .TP | |
129 | .BR "\-t, \-\-type TYPE" | |
130 | Context type. You can repeat this option on the command line. Please | |
131 | use "lttng add-context \-h" to list all available types. | |
132 | .RE | |
133 | .PP | |
6991b181 | 134 | |
22019883 MD |
135 | .PP |
136 | \fBcalibrate\fP [OPTIONS] | |
137 | .RS | |
6991b181 DG |
138 | Quantify LTTng overhead |
139 | ||
140 | The LTTng calibrate command can be used to find out the combined average | |
141 | overhead of the LTTng tracer and the instrumentation mechanisms used. This | |
142 | overhead can be calibrated in terms of time or using any of the PMU performance | |
143 | counter available on the system. | |
144 | ||
145 | For now, the only calibration implemented is that of the kernel function | |
146 | instrumentation (kretprobes). | |
147 | ||
148 | * Calibrate kernel function instrumentation | |
149 | ||
150 | Let's use an example to show this calibration. We use an i7 processor with 4 | |
151 | general-purpose PMU registers. This information is available by issuing dmesg, | |
152 | looking for "generic registers". | |
153 | ||
154 | This sequence of commands will gather a trace executing a kretprobe hooked on | |
155 | an empty function, gathering PMU counters LLC (Last Level Cache) misses | |
c9e32613 | 156 | information (see lttng add-context \-\-help to see the list of available PMU |
6991b181 DG |
157 | counters). |
158 | ||
22019883 | 159 | .nf |
6991b181 | 160 | # lttng create calibrate-function |
22019883 MD |
161 | # lttng enable-event calibrate \-\-kernel \\ |
162 | \-\-function lttng_calibrate_kretprobe | |
163 | # lttng add-context \-\-kernel \-t perf:LLC-load-misses \\ | |
164 | \-t perf:LLC-store-misses \\ | |
165 | \-t perf:LLC-prefetch-misses | |
6991b181 DG |
166 | # lttng start |
167 | # for a in $(seq 1 10); do \\ | |
c9e32613 | 168 | lttng calibrate \-\-kernel \-\-function; |
6991b181 DG |
169 | done |
170 | # lttng destroy | |
22019883 MD |
171 | # babeltrace $(ls \-1drt ~/lttng-traces/calibrate-function-* \\ |
172 | | tail \-n 1) | |
173 | .fi | |
6991b181 DG |
174 | |
175 | The output from babeltrace can be saved to a text file and opened in a | |
176 | spreadsheet (e.g. oocalc) to focus on the per-PMU counter delta between | |
177 | consecutive "calibrate_entry" and "calibrate_return" events. Note that these | |
178 | counters are per-CPU, so scheduling events would need to be present to account | |
179 | for migration between CPU. Therefore, for calibration purposes, only events | |
180 | staying on the same CPU must be considered. | |
181 | ||
182 | The average result, for the i7, on 10 samples: | |
183 | ||
22019883 | 184 | .nf |
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185 | Average Std.Dev. |
186 | perf_LLC_load_misses: 5.0 0.577 | |
187 | perf_LLC_store_misses: 1.6 0.516 | |
188 | perf_LLC_prefetch_misses: 9.0 14.742 | |
22019883 | 189 | .fi |
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190 | |
191 | As we can notice, the load and store misses are relatively stable across runs | |
192 | (their standard deviation is relatively low) compared to the prefetch misses. | |
193 | We can conclude from this information that LLC load and store misses can be | |
194 | accounted for quite precisely, but prefetches within a function seems to behave | |
195 | too erratically (not much causality link between the code executed and the CPU | |
196 | prefetch activity) to be accounted for. | |
6991b181 DG |
197 | |
198 | .B OPTIONS: | |
199 | ||
22019883 MD |
200 | .TP |
201 | .BR "\-h, \-\-help" | |
202 | Show summary of possible options and commands. | |
203 | .TP | |
204 | .BR "\-k, \-\-kernel" | |
205 | Apply for the kernel tracer | |
206 | .TP | |
207 | .BR "\-u, \-\-userspace" | |
208 | Apply for the user-space tracer | |
209 | .TP | |
210 | .BR "\-\-function" | |
211 | Dynamic function entry/return probe (default) | |
212 | .RE | |
213 | .PP | |
6991b181 | 214 | |
ee2758e5 | 215 | .PP |
feb3ca56 | 216 | \fBcreate\fP [NAME] [OPTIONS] |
ee2758e5 | 217 | .RS |
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218 | Create tracing session. |
219 | ||
220 | A tracing session contains channel(s) which contains event(s). It is domain | |
e256d661 | 221 | agnostic, meaning that channels and events can be enabled for the |
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222 | user-space tracer and/or the kernel tracer. It acts like a container |
223 | aggregating multiple tracing sources. | |
224 | ||
225 | On creation, a \fB.lttngrc\fP file is created in your $HOME directory | |
226 | containing the current session name. If NAME is omitted, a session name is | |
fa072eae | 227 | automatically created having this form: 'auto-yyyymmdd-hhmmss'. |
6991b181 | 228 | |
c9e32613 | 229 | If no \fB\-o, \-\-output\fP is specified, the traces will be written in |
6991b181 | 230 | $HOME/lttng-traces. |
feb0f3e5 AM |
231 | |
232 | The $HOME environment variable can be overridden by defining the environment | |
233 | variable LTTNG_HOME. This is useful when the user running the commands has | |
234 | a non-writeable home directory. | |
6991b181 | 235 | |
0841762c DG |
236 | The session name MUST NOT contain the character '/'. |
237 | ||
6991b181 DG |
238 | .B OPTIONS: |
239 | ||
ee2758e5 MD |
240 | .TP |
241 | .BR "\-h, \-\-help" | |
242 | Show summary of possible options and commands. | |
243 | .TP | |
244 | .BR "\-\-list-options" | |
245 | Simple listing of options | |
246 | .TP | |
247 | .BR "\-o, \-\-output PATH" | |
248 | Specify output path for traces | |
249 | .TP | |
250 | .BR "\-\-no-output" | |
e256d661 | 251 | Traces will not be output |
ee2758e5 MD |
252 | .TP |
253 | .BR "\-\-snapshot" | |
254 | Set the session in snapshot mode. Created in no-output mode and uses the | |
e256d661 | 255 | URL, if one is specified, as the default snapshot output. Every channel will be set |
ee2758e5 | 256 | in overwrite mode and with mmap output (splice not supported). |
0794f51b | 257 | .TP |
05287bd3 | 258 | .BR "\-\-live [USEC]" |
0794f51b DG |
259 | Set the session exclusively in live mode. The paremeter is the delay in micro |
260 | seconds before the data is flushed and streamed. The live mode allows you to | |
261 | stream the trace and view it while it's being recorded by any tracer. For that, | |
262 | you need a lttng-relayd and this session requires a network URL (\-U or | |
05287bd3 DG |
263 | \-C/\-D). If no USEC nor URL is provided, the default is to use a timer value |
264 | set to 1000000 and the network URL set to net://127.0.0.1. | |
0794f51b DG |
265 | |
266 | To read a live session, you can use babeltrace(1) or the live streaming | |
267 | protocol in doc/live-reading-protocol.txt. Here is an example: | |
268 | ||
269 | .nf | |
270 | $ lttng-relayd -o /tmp/lttng | |
271 | $ lttng create --live 200000 -U net://localhost | |
272 | $ lttng enable-event -a --userspace | |
273 | $ lttng start | |
274 | .fi | |
275 | ||
276 | After the start, you'll be able to read the events while they are being | |
277 | recorded in /tmp/lttng. | |
6b8f2e64 | 278 | |
ee2758e5 MD |
279 | .TP |
280 | .BR "\-U, \-\-set-url=URL" | |
281 | Set URL for the consumer output destination. It is persistent for the | |
282 | session lifetime. Redo the command to change it. This will set both data | |
283 | and control URL for network. | |
284 | .TP | |
285 | .BR "\-C, \-\-ctrl-url=URL" | |
286 | Set control path URL. (Must use -D also) | |
287 | .TP | |
288 | .BR "\-D, \-\-data-url=URL" | |
289 | Set data path URL. (Must use -C also) | |
290 | .PP | |
6b8f2e64 DG |
291 | Using these options, each API call can be controlled individually. For |
292 | instance, \-C does not enable the consumer automatically. You'll need the \-e | |
293 | option for that. | |
294 | ||
785d2d0d DG |
295 | .B URL FORMAT: |
296 | ||
297 | proto://[HOST|IP][:PORT1[:PORT2]][/TRACE_PATH] | |
298 | ||
299 | Supported protocols are (proto): | |
ee2758e5 MD |
300 | .TP |
301 | .BR "file://..." | |
302 | Local filesystem full path. | |
785d2d0d | 303 | |
ee2758e5 MD |
304 | .TP |
305 | .BR "net://..." | |
306 | This will use the default network transport layer which is TCP for both | |
307 | control (PORT1) and data port (PORT2). The default ports are | |
308 | respectively 5342 and 5343. Note that net[6]:// is not yet supported. | |
785d2d0d | 309 | |
ee2758e5 MD |
310 | .TP |
311 | .BR "tcp[6]://..." | |
312 | Can only be used with -C and -D together | |
785d2d0d DG |
313 | |
314 | NOTE: IPv6 address MUST be enclosed in brackets '[]' (rfc2732) | |
6b8f2e64 DG |
315 | |
316 | .B EXAMPLES: | |
317 | ||
ee2758e5 | 318 | .nf |
6b8f2e64 | 319 | # lttng create -U net://192.168.1.42 |
ee2758e5 | 320 | .fi |
6b8f2e64 DG |
321 | Uses TCP and default ports for the given destination. |
322 | ||
ee2758e5 | 323 | .nf |
6b8f2e64 | 324 | # lttng create -U net6://[fe80::f66d:4ff:fe53:d220] |
ee2758e5 | 325 | .fi |
6b8f2e64 DG |
326 | Uses TCP, default ports and IPv6. |
327 | ||
ee2758e5 | 328 | .nf |
6b8f2e64 | 329 | # lttng create s1 -U net://myhost.com:3229 |
6991b181 | 330 | .fi |
ee2758e5 MD |
331 | Create session s1 and set its consumer to myhost.com on port 3229 for control. |
332 | .RE | |
333 | .PP | |
6991b181 | 334 | |
f2b14ef1 MD |
335 | .PP |
336 | \fBdestroy\fP [NAME] [OPTIONS] | |
337 | .RS | |
6991b181 DG |
338 | Teardown tracing session |
339 | ||
340 | Free memory on the session daemon and tracer side. It's gone! | |
341 | ||
342 | If NAME is omitted, the session name is taken from the .lttngrc file. | |
6991b181 DG |
343 | |
344 | .B OPTIONS: | |
345 | ||
f2b14ef1 MD |
346 | .TP |
347 | .BR "\-h, \-\-help" | |
348 | Show summary of possible options and commands. | |
349 | .TP | |
350 | .BR "\-a, \-\-all" | |
351 | Destroy all sessions | |
352 | .TP | |
353 | .BR "\-\-list-options" | |
354 | Simple listing of options | |
355 | .RE | |
356 | .PP | |
6991b181 | 357 | |
05be3802 MD |
358 | .PP |
359 | \fBenable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS] | |
360 | .RS | |
6991b181 DG |
361 | Enable tracing channel |
362 | ||
004f3466 DG |
363 | To enable an event, you must enable both the event and the channel that |
364 | contains it. | |
b883c01b | 365 | |
c9e32613 | 366 | If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc |
6991b181 | 367 | file. |
7972aab2 | 368 | |
05be3802 MD |
369 | Exactly one of \-k or -u must be specified. |
370 | ||
7972aab2 | 371 | It is important to note that if a certain type of buffers is used, the session |
bd337b98 | 372 | will be set with that type and all other subsequent channel needs to have the |
7972aab2 | 373 | same type. |
bd337b98 | 374 | |
d2f11c4a DG |
375 | Note that once the session has been started and enabled on the tracer side, |
376 | it's not possible anymore to enable a new channel for that session. | |
6991b181 DG |
377 | |
378 | .B OPTIONS: | |
379 | ||
05be3802 MD |
380 | .TP |
381 | .BR "\-h, \-\-help" | |
382 | Show this help | |
383 | .TP | |
384 | .BR "\-\-list-options" | |
385 | Simple listing of options | |
386 | .TP | |
387 | .BR "\-s, \-\-session NAME" | |
388 | Apply on session name | |
389 | .TP | |
390 | .BR "\-k, \-\-kernel" | |
391 | Apply to the kernel tracer | |
392 | .TP | |
393 | .BR "\-u, \-\-userspace" | |
394 | Apply to the user-space tracer | |
395 | .TP | |
396 | .BR "\-\-discard" | |
397 | Discard event when subbuffers are full (default) | |
398 | .TP | |
399 | .BR "\-\-overwrite" | |
400 | Flight recorder mode : overwrites events when subbuffers are full | |
401 | .TP | |
402 | .BR "\-\-subbuf-size SIZE" | |
403 | Subbuffer size in bytes {+k,+M,+G}. | |
404 | (default UST uid: 131072, UST pid: 4096, kernel: 262144, metadata: 4096) | |
405 | Rounded up to the next power of 2. | |
406 | ||
407 | The minimum subbuffer size, for each tracer, is the max value between | |
408 | the default above and the system page size. You can issue this command | |
409 | to get the current page size on your system: \fB$ getconf PAGE_SIZE\fP | |
410 | .TP | |
411 | .BR "\-\-num-subbuf NUM" | |
412 | Number of subbuffers. (default UST uid: 4, UST pid: 4, kernel: 4, | |
413 | metadata: 2) Rounded up to the next power of 2. | |
414 | .TP | |
415 | .BR "\-\-switch-timer USEC" | |
416 | Switch subbuffer timer interval in µsec. | |
417 | (default UST uid: 0, UST pid: 0, kernel: 0, metadata: 0) | |
418 | .TP | |
419 | .BR "\-\-read-timer USEC" | |
420 | Read timer interval in µsec. | |
421 | (default UST uid: 0, UST pid: 0, kernel: 200000, metadata: 0) | |
422 | .TP | |
423 | .BR "\-\-output TYPE" | |
424 | Channel output type. Possible values: mmap, splice | |
425 | (default UST uid: mmap, UST pid: mmap, kernel: splice, metadata: mmap) | |
426 | .TP | |
427 | .BR "\-\-buffers-uid" | |
428 | Use per UID buffer (\-u only). Buffers are shared between applications | |
429 | that have the same UID. | |
430 | .TP | |
431 | .BR "\-\-buffers-pid" | |
432 | Use per PID buffer (\-u only). Each application has its own buffers. | |
433 | .TP | |
434 | .BR "\-\-buffers-global" | |
435 | Use shared buffer for the whole system (\-k only) | |
436 | .TP | |
437 | .BR "\-C, \-\-tracefile-size SIZE" | |
438 | Maximum size of each tracefile within a stream (in bytes). | |
439 | 0 means unlimited. (default: 0) | |
440 | .TP | |
441 | .BR "\-W, \-\-tracefile-count COUNT" | |
442 | Used in conjunction with \-C option, this will limit the number of files | |
443 | created to the specified count. 0 means unlimited. (default: 0) | |
1624d5b7 JD |
444 | |
445 | .B EXAMPLES: | |
446 | ||
05be3802 MD |
447 | .nf |
448 | $ lttng enable-channel -k -C 4096 -W 32 chan1 | |
449 | .fi | |
e256d661 | 450 | For each stream, the maximum size of each trace file will be 4096 bytes and |
cea28771 | 451 | there will be a maximum of 32 different files. The file count is appended after |
1624d5b7 JD |
452 | the stream number as seen in the following example. The last trace file is |
453 | smaller than 4096 since it was not completely filled. | |
454 | ||
05be3802 | 455 | .nf |
1624d5b7 JD |
456 | ~/lttng-traces/[...]/chan1_0_0 (4096) |
457 | ~/lttng-traces/[...]/chan1_0_1 (4096) | |
458 | ~/lttng-traces/[...]/chan1_0_2 (3245) | |
459 | ~/lttng-traces/[...]/chan1_1_0 (4096) | |
460 | ... | |
05be3802 | 461 | .fi |
1624d5b7 | 462 | |
05be3802 MD |
463 | .nf |
464 | $ lttng enable-channel -k -C 4096 | |
465 | .fi | |
1624d5b7 JD |
466 | This will create trace files of 4096 bytes and will create new ones as long as |
467 | there is data available. | |
05be3802 MD |
468 | .RE |
469 | .PP | |
6991b181 | 470 | |
6a240cd9 MD |
471 | .PP |
472 | \fBenable-event\fP NAME[,NAME2,...] [-k|-u] [OPTIONS] | |
473 | .RS | |
6991b181 DG |
474 | Enable tracing event |
475 | ||
c9e32613 | 476 | A tracing event is always assigned to a channel. If \fB\-c, \-\-channel\fP is |
6991b181 | 477 | omitted, a default channel named '\fBchannel0\fP' is created and the event is |
85076754 MD |
478 | added to it. If \fB\-c, \-\-channel\fP is omitted, but a non-default |
479 | channel already exists within the session, an error is returned. For the | |
480 | user-space tracer, using \fB\-a, \-\-all\fP is the same as using the | |
481 | wildcard "*". | |
6991b181 | 482 | |
c9e32613 | 483 | If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc |
6991b181 | 484 | file. |
6991b181 DG |
485 | |
486 | .B OPTIONS: | |
487 | ||
6a240cd9 MD |
488 | .TP |
489 | .BR "\-h, \-\-help" | |
490 | Show summary of possible options and commands. | |
491 | .TP | |
492 | .BR "\-\-list-options" | |
493 | Simple listing of options | |
494 | .TP | |
495 | .BR "\-s, \-\-session NAME" | |
496 | Apply on session name | |
497 | .TP | |
498 | .BR "\-c, \-\-channel NAME" | |
499 | Apply on channel name | |
500 | .TP | |
501 | .BR "\-a, \-\-all" | |
e256d661 | 502 | Enable all tracepoints and syscalls. This actually enables a single |
6a240cd9 MD |
503 | wildcard event "*". |
504 | .TP | |
505 | .BR "\-k, \-\-kernel" | |
506 | Apply for the kernel tracer | |
507 | .TP | |
508 | .BR "\-u, \-\-userspace" | |
509 | Apply for the user-space tracer | |
510 | .TP | |
bed69e7d DG |
511 | .BR "\-j, \-\-jul" |
512 | Apply for Java application using Java Util Logging interface (JUL) | |
513 | .TP | |
6a240cd9 | 514 | .BR "\-\-tracepoint" |
e256d661 | 515 | Tracepoint event (default). Userspace tracer supports wildcards at the end |
6a240cd9 MD |
516 | of string. Don't forget to quote to deal with bash expansion. |
517 | e.g.: | |
6991b181 | 518 | .nf |
6991b181 DG |
519 | "*" |
520 | "app_component:na*" | |
6991b181 | 521 | .fi |
6a240cd9 MD |
522 | .TP |
523 | .BR "\-\-loglevel NAME" | |
524 | Tracepoint loglevel range from 0 to loglevel. Listed in the help (\-h). | |
bc358d3e DG |
525 | For the JUL domain, the loglevel ranges are detailed with the \-\-help |
526 | option thus starting from SEVERE to FINEST. | |
6a240cd9 MD |
527 | .TP |
528 | .BR "\-\-loglevel-only NAME" | |
529 | Tracepoint loglevel (only this loglevel). | |
530 | The loglevel or loglevel-only options should be combined with a | |
531 | tracepoint name or tracepoint wildcard. | |
532 | .TP | |
533 | .BR "\-\-probe (addr | symbol | symbol+offset)" | |
534 | Dynamic probe. Addr and offset can be octal (0NNN...), decimal (NNN...) | |
535 | or hexadecimal (0xNNN...) | |
536 | .TP | |
537 | .BR "\-\-function (addr | symbol | symbol+offset)" | |
538 | Dynamic function entry/return probe. Addr and offset can be octal | |
539 | (0NNN...), decimal (NNN...) or hexadecimal (0xNNN...) | |
540 | .TP | |
541 | .BR "\-\-syscall" | |
542 | System call event. Enabling syscalls tracing (kernel tracer), you will | |
543 | not be able to disable them with disable-event. This is a known | |
544 | limitation. You can disable the entire channel to do the trick. | |
545 | .TP | |
546 | .BR "\-\-filter 'expression'" | |
547 | Set a filter on a newly enabled event. Filter expression on event | |
e256d661 JG |
548 | fields and context. The event will be recorded if the filter's |
549 | expression evaluates to TRUE. Only specify on first activation of a | |
550 | given event within a session. | |
551 | Specifying a filter is only allowed when enabling events within a session before | |
6a240cd9 MD |
552 | tracing is started. If the filter fails to link with the event |
553 | within the traced domain, the event will be discarded. | |
e256d661 | 554 | Filtering is currently only implemented for the user-space tracer. |
6a240cd9 MD |
555 | |
556 | Expression examples: | |
557 | ||
558 | .nf | |
559 | 'intfield > 500 && intfield < 503' | |
560 | '(strfield == "test" || intfield != 10) && intfield > 33' | |
561 | 'doublefield > 1.1 && intfield < 5.3' | |
562 | .fi | |
563 | ||
564 | Wildcards are allowed at the end of strings: | |
565 | 'seqfield1 == "te*"' | |
566 | In string literals, the escape character is a '\\'. Use '\\*' for | |
e256d661 JG |
567 | the '*' character, and '\\\\' for the '\\' character sequence. Wildcard |
568 | matches any sequence of characters, including an empty sub-string | |
569 | (matches 0 or more characters). | |
6a240cd9 | 570 | |
e256d661 JG |
571 | Context information can be used for filtering. The examples below shows |
572 | usage of context filtering on the process name (using a wildcard), process ID | |
573 | range, and unique thread ID. The process and thread IDs of | |
6a240cd9 MD |
574 | running applications can be found under columns "PID" and "LWP" of the |
575 | "ps -eLf" command. | |
576 | ||
577 | .nf | |
578 | '$ctx.procname == "demo*"' | |
579 | '$ctx.vpid >= 4433 && $ctx.vpid < 4455' | |
580 | '$ctx.vtid == 1234' | |
581 | .fi | |
582 | ||
bccd20a3 JI |
583 | .TP |
584 | .BR "\-x, \-\-exclude LIST" | |
585 | Add exclusions to UST tracepoints: | |
586 | Events that match any of the items in the comma-separated LIST are not | |
587 | enabled, even if they match a wildcard definition of the event. | |
588 | ||
589 | This option is also applicable with the \fB\-a, \-\-all\fP option, | |
590 | in which case all UST tracepoints are enabled except the ones whose | |
591 | names match any of the items in LIST. | |
6a240cd9 MD |
592 | .RE |
593 | .PP | |
6991b181 | 594 | |
272c6a17 MD |
595 | .PP |
596 | \fBdisable-channel\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS] | |
597 | .RS | |
6991b181 DG |
598 | Disable tracing channel |
599 | ||
e256d661 JG |
600 | Disabling a channel disables the tracing of all of the channel's events. A channel |
601 | can be reenabled by calling \fBlttng enable-channel NAME\fP again. | |
6991b181 | 602 | |
c9e32613 | 603 | If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc |
6991b181 | 604 | file. |
6991b181 DG |
605 | |
606 | .B OPTIONS: | |
607 | ||
272c6a17 MD |
608 | .TP |
609 | .BR "\-h, \-\-help" | |
610 | Show summary of possible options and commands. | |
611 | .TP | |
612 | .BR "\-\-list-options" | |
613 | Simple listing of options | |
614 | .TP | |
615 | .BR "\-s, \-\-session NAME" | |
616 | Apply on session name | |
617 | .TP | |
618 | .BR "\-k, \-\-kernel" | |
619 | Apply for the kernel tracer | |
620 | .TP | |
621 | .BR "\-u, \-\-userspace" | |
622 | Apply for the user-space tracer | |
623 | .RE | |
624 | .PP | |
6991b181 | 625 | |
c138a39b MD |
626 | .PP |
627 | \fBdisable-event\fP NAME[,NAME2,...] (\-k | \-u) [OPTIONS] | |
628 | .RS | |
6991b181 DG |
629 | Disable tracing event |
630 | ||
631 | The event, once disabled, can be re-enabled by calling \fBlttng enable-event | |
632 | NAME\fP again. | |
633 | ||
c9e32613 | 634 | If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc |
6991b181 | 635 | file. |
6991b181 | 636 | |
85076754 MD |
637 | If \fB\-c, \-\-channel\fP is omitted, the default channel name is used. |
638 | If \fB\-c, \-\-channel\fP is omitted, but a non-default channel already | |
639 | exists within the session, an error is returned. | |
640 | ||
6991b181 DG |
641 | .B OPTIONS: |
642 | ||
c138a39b MD |
643 | .TP |
644 | .BR "\-h, \-\-help" | |
645 | Show summary of possible options and commands. | |
646 | .TP | |
647 | .BR "\-\-list-options" | |
648 | Simple listing of options | |
649 | .TP | |
650 | .BR "\-s, \-\-session NAME" | |
651 | Apply on session name | |
652 | .TP | |
85076754 MD |
653 | .BR "\-c, \-\-channel NAME" |
654 | Apply on channel name | |
655 | .TP | |
c138a39b MD |
656 | .BR "\-a, \-\-all-events" |
657 | Disable all events. This does NOT disable "*" but rather every known | |
658 | events of the session. | |
659 | .TP | |
660 | .BR "\-k, \-\-kernel" | |
661 | Apply for the kernel tracer | |
662 | .TP | |
663 | .BR "\-u, \-\-userspace" | |
664 | Apply for the user-space tracer | |
bed69e7d DG |
665 | .TP |
666 | .BR "\-j, \-\-jul" | |
667 | Apply for Java application using Java Util Logging interface (JUL) | |
c138a39b MD |
668 | .RE |
669 | .PP | |
6991b181 | 670 | |
747361fe MD |
671 | .PP |
672 | \fBlist\fP [OPTIONS] [SESSION [SESSION OPTIONS]] | |
673 | .RS | |
c9e32613 | 674 | List tracing session information. |
6991b181 DG |
675 | |
676 | With no arguments, it will list available tracing session(s). | |
677 | ||
fa072eae YB |
678 | With the session name, it will display the details of the session including |
679 | the trace file path, the associated channels and their state (activated | |
d829b38c | 680 | and deactivated), the activated events and more. |
fa072eae | 681 | |
c9e32613 | 682 | With \-k alone, it will list all available kernel events (except the system |
6991b181 | 683 | calls events). |
bed69e7d DG |
684 | With \-j alone, the available JUL event from registered application will be |
685 | list. The event corresponds to the Logger name in the Java JUL application. | |
c9e32613 DG |
686 | With \-u alone, it will list all available user-space events from registered |
687 | applications. Here is an example of 'lttng list \-u': | |
6991b181 | 688 | |
747361fe | 689 | .nf |
6991b181 DG |
690 | PID: 7448 - Name: /tmp/lttng-ust/tests/hello/.libs/lt-hello |
691 | ust_tests_hello:tptest_sighandler (type: tracepoint) | |
692 | ust_tests_hello:tptest (type: tracepoint) | |
747361fe | 693 | .fi |
6991b181 DG |
694 | |
695 | You can now enable any event listed by using the name : | |
696 | \fBust_tests_hello:tptest\fP. | |
6991b181 DG |
697 | |
698 | .B OPTIONS: | |
699 | ||
747361fe MD |
700 | .TP |
701 | .BR "\-h, \-\-help" | |
702 | Show summary of possible options and commands. | |
703 | .TP | |
704 | .BR "\-\-list-options" | |
705 | Simple listing of options | |
706 | .TP | |
707 | .BR "\-k, \-\-kernel" | |
708 | Select kernel domain | |
709 | .TP | |
710 | .BR "\-u, \-\-userspace" | |
711 | Select user-space domain. | |
bed69e7d DG |
712 | .TP |
713 | .BR "\-j, \-\-jul" | |
714 | Apply for Java application using JUL | |
715 | .TP | |
716 | .BR "\-f, \-\-fields" | |
717 | List event fields | |
6991b181 | 718 | |
747361fe | 719 | .PP |
6b8f2e64 DG |
720 | .B SESSION OPTIONS: |
721 | ||
747361fe MD |
722 | .TP |
723 | .BR "\-c, \-\-channel NAME" | |
724 | List details of a channel | |
725 | .TP | |
726 | .BR "\-d, \-\-domain" | |
727 | List available domain(s) | |
728 | .RE | |
729 | .PP | |
6991b181 | 730 | |
7c96a096 MD |
731 | .PP |
732 | \fBset-session\fP NAME [OPTIONS] | |
733 | .RS | |
6991b181 DG |
734 | Set current session name |
735 | ||
736 | Will change the session name in the .lttngrc file. | |
6991b181 DG |
737 | |
738 | .B OPTIONS: | |
739 | ||
7c96a096 MD |
740 | .TP |
741 | .BR "\-h, \-\-help" | |
742 | Show summary of possible options and commands. | |
743 | .TP | |
744 | .BR "\-\-list-options" | |
745 | Simple listing of options | |
746 | .RE | |
747 | .PP | |
6991b181 | 748 | |
8df3bfe9 MD |
749 | .PP |
750 | \fBsnapshot\fP [OPTIONS] ACTION | |
751 | .RS | |
b872baea | 752 | Snapshot command for LTTng session. |
b872baea DG |
753 | |
754 | .B OPTIONS: | |
755 | ||
8df3bfe9 MD |
756 | .TP |
757 | .BR "\-h, \-\-help" | |
758 | Show summary of possible options and commands. | |
759 | .TP | |
760 | .BR "\-\-list-options" | |
761 | Simple listing of options | |
b872baea | 762 | |
8df3bfe9 | 763 | .PP |
b872baea DG |
764 | .B ACTION: |
765 | ||
8df3bfe9 | 766 | .TP |
b872baea DG |
767 | \fBadd-output\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] <URL> | -C <URL> -D <URL> |
768 | ||
769 | Setup and add an snapshot output for a session. Output are the destination | |
770 | where the snapshot will be sent. Only one output is permitted. To change it, | |
771 | you'll need to delete it and add back the new one. | |
772 | ||
8df3bfe9 | 773 | .TP |
b872baea DG |
774 | \fBdel-output\fP ID | NAME [-s <NAME>] |
775 | ||
776 | Delete an output for a session using the ID. You can either specify the | |
777 | output's ID that can be found with list-output or the name. | |
778 | ||
8df3bfe9 | 779 | .TP |
b872baea DG |
780 | \fBlist-output\fP [-s <NAME>] |
781 | ||
782 | List the output of a session. Attributes of the output are printed. | |
783 | ||
8df3bfe9 | 784 | .TP |
b872baea DG |
785 | \fBrecord\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] [<URL> | -C <URL> -D <URL>] |
786 | ||
787 | Snapshot a session's buffer(s) for all domains. If an URL is specified, it is | |
788 | used instead of a previously added output. Specifying only a name or/and a max | |
789 | size will override the current output values. For instance, you can record a | |
790 | snapshot with a custom maximum size or with a different name. | |
791 | ||
8df3bfe9 | 792 | .nf |
1ac1098f | 793 | $ lttng snapshot add-output -n mysnapshot file:///data/snapshot |
b872baea DG |
794 | [...] |
795 | $ lttng snapshot record -n new_name_snapshot | |
8df3bfe9 | 796 | .fi |
b872baea DG |
797 | |
798 | The above will create a snapshot in /data/snapshot/new_name_snapshot* directory | |
799 | rather then in mysnapshot*/ | |
b872baea | 800 | |
8df3bfe9 MD |
801 | .PP |
802 | .B DETAILED ACTION OPTIONS | |
b872baea | 803 | |
8df3bfe9 MD |
804 | .TP |
805 | .BR "\-s, \-\-session NAME" | |
806 | Apply to session name. | |
807 | .TP | |
808 | .BR "\-n, \-\-name NAME" | |
809 | Name of the snapshot's output. | |
810 | .TP | |
811 | .BR "\-m, \-\-max-size SIZE" | |
a8f307d8 SM |
812 | Maximum size in bytes of the snapshot. The maxium size does not include the |
813 | metadata file. Human readable format is accepted: {+k,+M,+G}. For instance, | |
814 | \-\-max-size 5M | |
8df3bfe9 MD |
815 | .TP |
816 | .BR "\-C, \-\-ctrl-url URL" | |
817 | Set control path URL. (Must use -D also) | |
818 | .TP | |
819 | .BR "\-D, \-\-data-url URL" | |
820 | Set data path URL. (Must use -C also) | |
821 | .RE | |
822 | .PP | |
b872baea | 823 | |
afb8ca1b MD |
824 | .PP |
825 | \fBstart\fP [NAME] [OPTIONS] | |
826 | .RS | |
6991b181 DG |
827 | Start tracing |
828 | ||
829 | It will start tracing for all tracers for a specific tracing session. | |
6991b181 | 830 | If NAME is omitted, the session name is taken from the .lttngrc file. |
6991b181 DG |
831 | |
832 | .B OPTIONS: | |
833 | ||
afb8ca1b MD |
834 | .TP |
835 | .BR "\-h, \-\-help" | |
836 | Show summary of possible options and commands. | |
837 | .TP | |
838 | .BR "\-\-list-options" | |
839 | Simple listing of options | |
840 | .RE | |
841 | .PP | |
6991b181 | 842 | |
6c09bfdb MD |
843 | .PP |
844 | \fBstop\fP [NAME] [OPTIONS] | |
845 | .RS | |
6991b181 DG |
846 | Stop tracing |
847 | ||
391b9c72 DG |
848 | It will stop tracing for all tracers for a specific tracing session. Before |
849 | returning, the command checks for data availability meaning that it will wait | |
850 | until the trace is readable for the session. Use \-\-no-wait to avoid this | |
851 | behavior. | |
6991b181 DG |
852 | |
853 | If NAME is omitted, the session name is taken from the .lttngrc file. | |
6991b181 DG |
854 | |
855 | .B OPTIONS: | |
856 | ||
6c09bfdb MD |
857 | .TP |
858 | .BR "\-h, \-\-help" | |
859 | Show summary of possible options and commands. | |
860 | .TP | |
861 | .BR "\-\-list-options" | |
862 | Simple listing of options | |
863 | .TP "\-\-no-wait" | |
864 | Don't wait for data availability. | |
865 | .RE | |
866 | .PP | |
6991b181 | 867 | |
5975c30a MD |
868 | .PP |
869 | \fBversion\fP | |
870 | .RS | |
6991b181 | 871 | Show version information |
6991b181 DG |
872 | |
873 | .B OPTIONS: | |
874 | ||
5975c30a MD |
875 | .TP |
876 | .BR "\-h, \-\-help" | |
877 | Show summary of possible options and commands. | |
878 | .TP | |
879 | .BR "\-\-list-options" | |
880 | Simple listing of options | |
881 | .RE | |
882 | .PP | |
6991b181 | 883 | |
5b4c1410 MD |
884 | .PP |
885 | \fBview\fP [SESSION_NAME] [OPTIONS] | |
886 | .RS | |
887 | View traces of a tracing session. By default, the babeltrace viewer | |
888 | will be used for text viewing. If SESSION_NAME is omitted, the session | |
889 | name is taken from the .lttngrc file. | |
6991b181 DG |
890 | |
891 | .B OPTIONS: | |
892 | ||
5b4c1410 MD |
893 | .TP |
894 | .BR "\-h, \-\-help" | |
895 | Show this help | |
896 | .TP | |
897 | .BR "\-\-list-options" | |
898 | Simple listing of options | |
899 | .TP | |
900 | .BR "\-t, \-\-trace-path PATH" | |
901 | Trace directory path for the viewer | |
902 | .TP | |
903 | .BR "\-e, \-\-viewer CMD" | |
904 | Specify viewer and/or options to use This will completely override the | |
905 | default viewers so please make sure to specify the full command. The | |
906 | trace directory path of the session will be appended at the end to the | |
907 | arguments | |
908 | .RE | |
909 | .PP | |
6991b181 | 910 | |
278eefc8 DG |
911 | .SH "JUL DOMAIN" |
912 | This section explains the JUL domain (\-j, \-\-jul) where JUL stands for Java | |
913 | Util Logging. You can use that feature by using the \fBliblttng-ust-jul.so\fP | |
914 | from the lttng-ust(3) project. | |
915 | ||
916 | The LTTng Java Agent uses JNI to link the UST tracer to the Java application | |
917 | that uses the agent. Thus, it behaves similarly to the UST domain (\-u). When | |
918 | enabling events with the JUL domain, you enable a Logger name that will then be | |
919 | mapped to a default UST tracepoint called \fBlttng_jul:jul_event\fP in the | |
920 | \fBlttng_jul_channel\fP. Using the lttng-ctl API, any JUL events must use the | |
921 | tracepoint event type (same as \-\-tracepoint). | |
922 | ||
923 | Because of the default immutable channel (\fBlttng_jul_channel\fP), the | |
924 | \fBenable-channel\fP command CAN NOT be used with the JUL domain thus not | |
925 | having any \-j option. | |
926 | ||
927 | For JUL event, loglevels are supported with the JUL ABI values. Use \fBlttng | |
928 | enable-event \-h\fP to list them. Wildcards are NOT supported except the "*" | |
929 | meaning all events (same as \-a). | |
930 | ||
931 | Exactly like the UST domain, if the Java application has the same UID as you, | |
932 | you can trace it. Same goes for the tracing group accessing root applications. | |
933 | ||
934 | Finally, you can list every Logger name that are available from JUL registered | |
935 | applications to the session daemon by using \fBlttng list \-j\fP. | |
936 | ||
937 | Here is an example on how to use this domain. | |
938 | ||
939 | .nf | |
940 | $ lttng list -j | |
941 | [...] | |
942 | $ lttng create aSession | |
943 | $ lttng enable-event -s aSession -j MyCustomLoggerName | |
944 | $ lttng start | |
945 | .fi | |
946 | ||
947 | More information can be found in the lttng-ust documentation, see | |
948 | java-util-logging.txt | |
949 | .PP | |
950 | ||
c206d957 | 951 | .SH "EXIT VALUES" |
b107a0b1 | 952 | .PP |
6b8f2e64 DG |
953 | On success 0 is returned and a positive value on error. Value of 1 means a command |
954 | error, 2 an undefined command, 3 a fatal error and 4 a command warning meaning that | |
955 | something went wrong during the command. | |
c206d957 | 956 | |
6b8f2e64 | 957 | Any other value above 10, please refer to |
b107a0b1 | 958 | .BR "<lttng/lttng-error.h>" |
6b8f2e64 DG |
959 | for a detailed list or use lttng_strerror() to get a human readable string of |
960 | the error code. | |
c206d957 | 961 | .PP |
b107a0b1 | 962 | |
6991b181 DG |
963 | .SH "ENVIRONMENT VARIABLES" |
964 | ||
965 | .PP | |
966 | Note that all command line options override environment variables. | |
967 | .PP | |
968 | ||
969 | .PP | |
05833633 | 970 | .IP "LTTNG_SESSIOND_PATH" |
c9e32613 DG |
971 | Allows one to specify the full session daemon binary path to lttng command line |
972 | tool. You can also use \-\-sessiond-path option having the same effect. | |
b107a0b1 MD |
973 | .PP |
974 | ||
6991b181 | 975 | .SH "SEE ALSO" |
6b8f2e64 DG |
976 | .BR babeltrace(1), |
977 | .BR lttng-ust(3), | |
978 | .BR lttng-sessiond(8), | |
979 | .BR lttng-relayd(8), | |
b107a0b1 | 980 | |
6991b181 DG |
981 | .SH "BUGS" |
982 | ||
b107a0b1 | 983 | .PP |
6991b181 | 984 | If you encounter any issues or usability problem, please report it on our |
6b8f2e64 DG |
985 | mailing list <lttng-dev@lists.lttng.org> to help improve this project or |
986 | at https://bugs.lttng.org which is a bugtracker. | |
b107a0b1 MD |
987 | .PP |
988 | ||
6991b181 DG |
989 | .SH "CREDITS" |
990 | ||
991 | .PP | |
c9e32613 | 992 | lttng is distributed under the GNU General Public License version 2. See the file |
6991b181 DG |
993 | COPYING for details. |
994 | .PP | |
995 | A Web site is available at http://lttng.org for more information on the LTTng | |
996 | project. | |
997 | .PP | |
998 | You can also find our git tree at http://git.lttng.org. | |
999 | .PP | |
1000 | Mailing lists for support and development: <lttng-dev@lists.lttng.org>. | |
1001 | .PP | |
1002 | You can find us on IRC server irc.oftc.net (OFTC) in #lttng. | |
1003 | .PP | |
1004 | .SH "THANKS" | |
1005 | ||
1006 | .PP | |
1007 | Thanks to Yannick Brosseau without whom this project would never have been so | |
1008 | lean and mean! Also thanks to the Ericsson teams working on tracing which | |
fa072eae | 1009 | helped us greatly with detailed bug reports and unusual test cases. |
6991b181 DG |
1010 | |
1011 | Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA | |
1012 | maintainer) and Jon Bernard for our Debian packages. | |
1013 | ||
1014 | Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de | |
1015 | Montreal for the LTTng journey. | |
c9e32613 | 1016 | .PP |
6991b181 DG |
1017 | .SH "AUTHORS" |
1018 | ||
1019 | .PP | |
1020 | lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and | |
1021 | David Goulet. More people have since contributed to it. It is currently | |
1022 | maintained by David Goulet <dgoulet@efficios.com>. | |
1023 | .PP |