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eba411c6 MD |
1 | .TH "LTTNG-UST" "3" "February 16, 2012" "" "" |
2 | ||
3 | .SH "NAME" | |
77ca1460 | 4 | lttng-ust \(em Linux Trace Toolkit Next Generation User-Space Tracer 2.x |
eba411c6 MD |
5 | |
6 | .SH "SYNOPSIS" | |
7 | ||
8 | .PP | |
9 | .nf | |
10 | Link liblttng-ust.so with applications, following this manpage. | |
11 | .fi | |
12 | .SH "DESCRIPTION" | |
13 | ||
14 | .PP | |
7c501923 | 15 | LTTng-UST, the Linux Trace Toolkit Next Generation Userspace Tracer, is a |
eba411c6 MD |
16 | port of the low-overhead tracing capabilities of the LTTng kernel tracer |
17 | to user-space. The library "liblttng-ust" enables tracing of | |
18 | applications and libraries. | |
19 | ||
641c659a MD |
20 | .SH "USAGE WITH TRACEF" |
21 | .PP | |
22 | The simplest way to add instrumentation to your code is by far the | |
fc0ec7f9 | 23 | tracef() API. To do it, in a nutshell: |
641c659a MD |
24 | |
25 | 1) #include <lttng/tracef.h> | |
26 | ||
27 | 2) /* in your code, use like a printf */ | |
28 | tracef("my message, this integer %d", 1234); | |
29 | ||
30 | 3) Link your program against liblttng-ust.so. | |
31 | ||
67ada458 MD |
32 | 4) Enable UST events when tracing with the following sequence of commands |
33 | from lttng-tools: | |
641c659a | 34 | |
aacb3774 | 35 | lttng create |
67ada458 | 36 | lttng enable-event -u -a |
aacb3774 | 37 | lttng start |
641c659a | 38 | [... run your program ...] |
aacb3774 MD |
39 | lttng stop |
40 | lttng view | |
641c659a MD |
41 | |
42 | That's it! | |
43 | ||
44 | If you want to have more flexibility and control on the event names, | |
45 | payload typing, etc, you can continue reading on and use the tracepoints | |
46 | below. "tracef()" is there for quick and dirty ad hoc instrumentation, | |
47 | whereas tracepoint.h is meant for thorough instrumentation of a code | |
48 | base to be integrated with an upstream project. | |
49 | .PP | |
50 | ||
e729155f MD |
51 | .SH "USAGE WITH TRACELOG" |
52 | .PP | |
53 | If you want to migrate existing logging (info, errors, ...) | |
54 | to LTTng UST, you can use the tracelog() interface. | |
55 | To do it, in a nutshell: | |
56 | ||
57 | 1) #include <lttng/tracelog.h> | |
58 | ||
59 | 2) /* in your code, use like a printf, with extra loglevel info. */ | |
60 | tracelog(info, "Message with integer %d", 1234); | |
61 | ||
62 | 3) Link your program against liblttng-ust.so. | |
63 | ||
64 | 4) Enable UST events when tracing with the following sequence of commands | |
65 | from lttng-tools: | |
66 | ||
67 | lttng create | |
68 | lttng enable-event -u "lttng_ust_tracelog:*" | |
69 | lttng start | |
70 | [... run your program ...] | |
71 | lttng stop | |
72 | lttng view | |
73 | ||
74 | That's it! | |
75 | ||
76 | You can replace the enable-event line above with a selection of | |
77 | loglevels, e.g.: | |
78 | ||
79 | lttng enable-event -u -a --loglevel INFO | |
80 | ||
81 | Which will gather all events from INFO and more important loglevels. | |
82 | ||
83 | .PP | |
84 | ||
641c659a | 85 | .SH "USAGE WITH TRACEPOINT" |
eba411c6 MD |
86 | .PP |
87 | The simple way to generate the lttng-ust tracepoint probes is to use the | |
88 | lttng-gen-tp(1) tool. See the lttng-gen-tp(1) manpage for explanation. | |
89 | .PP | |
90 | ||
91 | .PP | |
92 | Here is the way to do it manually, without the lttng-gen-tp(1) helper | |
93 | script, through an example: | |
94 | .PP | |
95 | ||
96 | .SH "CREATION OF TRACEPOINT PROVIDER" | |
97 | ||
98 | .nf | |
99 | ||
100 | To create a tracepoint provider, within a build tree similar to | |
dfc45f18 MD |
101 | examples/easy-ust installed with lttng-ust documentation, see |
102 | sample_component_provider.h for the general layout. You will need to | |
103 | define TRACEPOINT_CREATE_PROBES before including your tracepoint | |
104 | provider probe in one source file of your application. See tp.c from | |
105 | easy-ust for an example of a tracepoint probe source file. This manpage | |
106 | will focus on the various types that can be recorded into a trace | |
107 | event: | |
eba411c6 MD |
108 | |
109 | TRACEPOINT_EVENT( | |
110 | /* | |
111 | * provider name, not a variable but a string starting with a | |
a106a9f8 | 112 | * letter and containing either letters, numbers or underscores. |
eba411c6 MD |
113 | * Needs to be the same as TRACEPOINT_PROVIDER. Needs to |
114 | * follow the namespacing guide-lines in lttng/tracepoint.h: | |
a106a9f8 JG |
115 | * |
116 | * Must be included before include tracepoint provider | |
eba411c6 MD |
117 | * ex.: project_event |
118 | * ex.: project_component_event | |
119 | * | |
120 | * Optional company name goes here | |
121 | * ex.: com_efficios_project_component_event | |
122 | * | |
123 | * In this example, "sample" is the project, and "component" is the | |
124 | * component. | |
125 | */ | |
126 | sample_component, | |
127 | ||
128 | /* | |
04fc40ad MD |
129 | * tracepoint name, characters permitted follow the same |
130 | * constraints as the provider name. The name of this example | |
131 | * event is "sample_event". | |
eba411c6 | 132 | */ |
04fc40ad | 133 | sample_event, |
eba411c6 MD |
134 | |
135 | /* | |
a106a9f8 | 136 | * TP_ARGS macro contains the arguments passed for the tracepoint |
eba411c6 MD |
137 | * it is in the following format |
138 | * TP_ARGS(type1, name1, type2, name2, ... type10, | |
139 | name10) | |
a106a9f8 JG |
140 | * where there can be from zero to ten elements. |
141 | * typeN is the datatype, such as int, struct or double **. | |
eba411c6 | 142 | * name is the variable name (in "int myInt" the name would be |
a106a9f8 | 143 | * myint) |
eba411c6 MD |
144 | * TP_ARGS() is valid to mean no arguments |
145 | * TP_ARGS(void) is valid too | |
146 | */ | |
147 | TP_ARGS(int, anint, int, netint, long *, values, | |
148 | char *, text, size_t, textlen, | |
149 | double, doublearg, float, floatarg), | |
150 | ||
151 | /* | |
a106a9f8 | 152 | * TP_FIELDS describes how to write the fields of the trace event. |
eba411c6 MD |
153 | * You can put expressions in the "argument expression" area, |
154 | * typically using the input arguments from TP_ARGS. | |
155 | */ | |
156 | TP_FIELDS( | |
157 | /* | |
158 | * ctf_integer: standard integer field. | |
159 | * args: (type, field name, argument expression) | |
160 | */ | |
161 | ctf_integer(int, intfield, anint) | |
162 | ctf_integer(long, longfield, anint) | |
163 | ||
164 | /* | |
165 | * ctf_integer_hex: integer field printed as hexadecimal. | |
166 | * args: (type, field name, argument expression) | |
167 | */ | |
168 | ctf_integer_hex(int, intfield2, anint) | |
169 | ||
170 | /* | |
171 | * ctf_integer_network: integer field in network byte | |
172 | * order. (_hex: printed as hexadecimal too) | |
173 | * args: (type, field name, argument expression) | |
174 | */ | |
175 | ctf_integer_network(int, netintfield, netint) | |
176 | ctf_integer_network_hex(int, netintfieldhex, netint) | |
177 | ||
178 | /* | |
179 | * ctf_array: a statically-sized array. | |
180 | * args: (type, field name, argument expression, value) | |
a106a9f8 | 181 | */ |
eba411c6 MD |
182 | ctf_array(long, arrfield1, values, 3) |
183 | ||
184 | /* | |
185 | * ctf_array_text: a statically-sized array, printed as | |
186 | * a string. No need to be terminated by a null | |
187 | * character. | |
2f65f1f5 | 188 | * Behavior is undefined if "text" argument is NULL. |
a106a9f8 | 189 | */ |
eba411c6 MD |
190 | ctf_array_text(char, arrfield2, text, 10) |
191 | ||
192 | /* | |
193 | * ctf_sequence: a dynamically-sized array. | |
194 | * args: (type, field name, argument expression, | |
195 | * type of length expression, length expression) | |
efbad5cc MD |
196 | * The "type of length expression" needs to be an |
197 | * unsigned type. As a reminder, "unsigned char" should | |
198 | * be preferred to "char", since the signedness of | |
199 | * "char" is implementation-defined. | |
2f65f1f5 | 200 | * Behavior is undefined if "text" argument is NULL. |
a106a9f8 | 201 | */ |
eba411c6 MD |
202 | ctf_sequence(char, seqfield1, text, |
203 | size_t, textlen) | |
204 | ||
205 | /* | |
206 | * ctf_sequence_text: a dynamically-sized array, printed | |
207 | * as string. No need to be null-terminated. | |
2f65f1f5 | 208 | * Behavior is undefined if "text" argument is NULL. |
eba411c6 MD |
209 | */ |
210 | ctf_sequence_text(char, seqfield2, text, | |
211 | size_t, textlen) | |
212 | ||
213 | /* | |
214 | * ctf_string: null-terminated string. | |
215 | * args: (field name, argument expression) | |
2f65f1f5 | 216 | * Behavior is undefined if "text" argument is NULL. |
eba411c6 MD |
217 | */ |
218 | ctf_string(stringfield, text) | |
219 | ||
220 | /* | |
221 | * ctf_float: floating-point number. | |
222 | * args: (type, field name, argument expression) | |
223 | */ | |
224 | ctf_float(float, floatfield, floatarg) | |
225 | ctf_float(double, doublefield, doublearg) | |
226 | ) | |
227 | ) | |
7d381d6e MD |
228 | |
229 | There can be an arbitrary number of tracepoint providers within an | |
230 | application, but they must each have their own provider name. Duplicate | |
231 | provider names are not allowed. | |
232 | ||
eba411c6 MD |
233 | .fi |
234 | ||
5883c06f MD |
235 | .SH "ASSIGNING LOGLEVEL TO EVENTS" |
236 | ||
237 | .nf | |
238 | ||
239 | Optionally, a loglevel can be assigned to a TRACEPOINT_EVENT using the | |
240 | following construct: | |
241 | ||
242 | TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, | |
243 | < event >, < loglevel_name >) | |
244 | ||
7c501923 | 245 | The first field is the provider name, the second field is the name of |
5883c06f MD |
246 | the tracepoint, and the third field is the loglevel name. A |
247 | TRACEPOINT_EVENT should be declared prior to the the TRACEPOINT_LOGLEVEL | |
248 | for a given tracepoint name. The TRACEPOINT_PROVIDER must be already | |
249 | declared before declaring a TRACEPOINT_LOGLEVEL. | |
250 | ||
251 | The loglevels go from 0 to 14. Higher numbers imply the most verbosity | |
252 | (higher event throughput expected. | |
a106a9f8 | 253 | |
5883c06f MD |
254 | Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels |
255 | semantic. Loglevels 7 through 13 offer more fine-grained selection of | |
256 | debug information. | |
a106a9f8 | 257 | |
5883c06f MD |
258 | TRACE_EMERG 0 |
259 | system is unusable | |
a106a9f8 | 260 | |
5883c06f MD |
261 | TRACE_ALERT 1 |
262 | action must be taken immediately | |
a106a9f8 | 263 | |
5883c06f MD |
264 | TRACE_CRIT 2 |
265 | critical conditions | |
a106a9f8 | 266 | |
5883c06f MD |
267 | TRACE_ERR 3 |
268 | error conditions | |
a106a9f8 | 269 | |
5883c06f MD |
270 | TRACE_WARNING 4 |
271 | warning conditions | |
a106a9f8 | 272 | |
5883c06f MD |
273 | TRACE_NOTICE 5 |
274 | normal, but significant, condition | |
a106a9f8 | 275 | |
5883c06f MD |
276 | TRACE_INFO 6 |
277 | informational message | |
a106a9f8 | 278 | |
5883c06f MD |
279 | TRACE_DEBUG_SYSTEM 7 |
280 | debug information with system-level scope (set of programs) | |
a106a9f8 | 281 | |
5883c06f MD |
282 | TRACE_DEBUG_PROGRAM 8 |
283 | debug information with program-level scope (set of processes) | |
a106a9f8 | 284 | |
5883c06f MD |
285 | TRACE_DEBUG_PROCESS 9 |
286 | debug information with process-level scope (set of modules) | |
a106a9f8 | 287 | |
5883c06f MD |
288 | TRACE_DEBUG_MODULE 10 |
289 | debug information with module (executable/library) scope (set of | |
290 | units) | |
a106a9f8 | 291 | |
5883c06f MD |
292 | TRACE_DEBUG_UNIT 11 |
293 | debug information with compilation unit scope (set of functions) | |
a106a9f8 | 294 | |
5883c06f MD |
295 | TRACE_DEBUG_FUNCTION 12 |
296 | debug information with function-level scope | |
a106a9f8 | 297 | |
5883c06f MD |
298 | TRACE_DEBUG_LINE 13 |
299 | debug information with line-level scope (TRACEPOINT_EVENT default) | |
a106a9f8 | 300 | |
5883c06f | 301 | TRACE_DEBUG 14 |
1e3b0059 | 302 | debug-level message |
5883c06f MD |
303 | |
304 | See lttng(1) for information on how to use LTTng-UST loglevels. | |
305 | ||
306 | .fi | |
307 | ||
eba411c6 MD |
308 | .SH "ADDING TRACEPOINTS TO YOUR CODE" |
309 | ||
310 | .nf | |
311 | ||
312 | Include the provider header in each C files you plan to instrument, | |
313 | following the building/linking directives in the next section. | |
314 | ||
315 | For instance, add within a function: | |
316 | ||
317 | tracepoint(ust_tests_hello, tptest, i, netint, values, | |
318 | text, strlen(text), dbl, flt); | |
319 | ||
320 | As a call to the tracepoint. It will only be activated when requested by | |
321 | lttng(1) through lttng-sessiond(8). | |
322 | ||
d646ca64 MD |
323 | Even though LTTng-UST supports tracepoint() call site duplicates having |
324 | the same provider and event name, it is recommended to use a | |
325 | provider event name pair only once within the source code to help | |
7c501923 | 326 | map events back to their call sites when analyzing the trace. |
8da6d0c8 DS |
327 | |
328 | Sometimes arguments to the probe are expensive to compute (e.g. | |
329 | take call stack). To avoid the computation when the tracepoint is | |
330 | disabled one can use more 'low level' tracepoint_enabled() and | |
331 | do_tracepoint() macros as following: | |
332 | ||
333 | if (tracepoint_enabled(ust_tests_hello, tptest)) { | |
334 | /* prepare arguments */ | |
335 | do_tracepoint(ust_tests_hello, tptest, i, netint, values, | |
336 | text, strlen(text), dbl, flt); | |
337 | } | |
338 | ||
339 | Here do_tracepoint() doesn't contain check if the tracepoint is enabled. | |
340 | Using tracepoint() in such scenario is dangerous since it also contains | |
341 | enabled check and thus race condition is possible in the following code | |
342 | if the tracepoint has been enabled after check in tracepoint_enabled() | |
343 | but before tracepoint(): | |
344 | ||
345 | if (tracepoint_enabled(provider, name)) { /* tracepoint is disabled */ | |
346 | prepare(args); | |
347 | } | |
348 | /* tracepoint is enabled by 'lttng' tool */ | |
349 | tracepoint(provider, name, args); /* args wasn't prepared properly */ | |
350 | ||
351 | Note also that neither tracepoint_enabled() nor do_tracepoint() have | |
352 | STAP_PROBEV() call so if you need it you should emit this call yourself. | |
353 | ||
eba411c6 MD |
354 | .fi |
355 | ||
356 | .SH "BUILDING/LINKING THE TRACEPOINT PROVIDER" | |
357 | ||
358 | .nf | |
359 | There are 2 ways to compile the Tracepoint Provider with the | |
360 | application: either statically or dynamically. Please follow | |
361 | carefully: | |
362 | ||
30b4246f PP |
363 | 1) Compile the Tracepoint Provider with the application, either |
364 | directly or through a static library (.a): | |
365 | - Into exactly one object of your application, define | |
eba411c6 | 366 | "TRACEPOINT_DEFINE" and include the tracepoint provider. |
9b6435af | 367 | - Use "\-I." for the compilation unit containing the tracepoint |
30b4246f PP |
368 | provider include (e.g., tp.c). |
369 | - Link the application with "\-llttng-ust" and "\-ldl". | |
eba411c6 MD |
370 | - Include the tracepoint provider header into all C files using |
371 | the provider. | |
a106a9f8 JG |
372 | - Examples: |
373 | - doc/examples/easy-ust/ sample.c sample_component_provider.h tp.c | |
374 | Makefile | |
375 | - doc/examples/hello-static-lib/ hello.c tp.c ust_test_hello.h Makefile | |
eba411c6 MD |
376 | |
377 | 2) Compile the Tracepoint Provider separately from the application, | |
378 | using dynamic linking: | |
379 | - Into exactly one object of your application: define | |
380 | "TRACEPOINT_DEFINE" _and_ also define | |
381 | "TRACEPOINT_PROBE_DYNAMIC_LINKAGE", then include the tracepoint | |
382 | provider header. | |
383 | - Include the tracepoint provider header into all instrumented C | |
384 | files that use the provider. | |
9b6435af AM |
385 | - Compile the tracepoint provider with "\-I.". |
386 | - Link the tracepoint provider with "\-llttng-ust". | |
387 | - Link application with "\-ldl". | |
eba411c6 MD |
388 | - Set a LD_PRELOAD environment to preload the tracepoint provider |
389 | shared object before starting the application when tracing is | |
13fb2d2c JG |
390 | needed. Another way is to dlopen the tracepoint probe when needed |
391 | by the application. | |
eba411c6 | 392 | - Example: |
a106a9f8 | 393 | - doc/examples/demo demo.c tp*.c ust_tests_demo*.h demo-trace Makefile |
eba411c6 | 394 | |
13fb2d2c JG |
395 | - Note about dlclose() usage: it is not safe to use dlclose on a |
396 | provider shared object that is being actively used for tracing due | |
397 | to a lack of reference counting from lttng-ust to the used shared | |
398 | object. | |
eba411c6 MD |
399 | - Enable instrumentation and control tracing with the "lttng" command |
400 | from lttng-tools. See lttng-tools doc/quickstart.txt. | |
2bda849d MD |
401 | - Note for C++ support: although an application instrumented with |
402 | tracepoints can be compiled with g++, tracepoint probes should be | |
403 | compiled with gcc (only tested with gcc so far). | |
eba411c6 MD |
404 | |
405 | .fi | |
406 | ||
0a7c55a5 MD |
407 | .SH "USING LTTNG UST WITH DAEMONS" |
408 | ||
409 | .nf | |
410 | Some extra care is needed when using liblttng-ust with daemon | |
411 | applications that call fork(), clone(), or BSD rfork() without a | |
412 | following exec() family system call. The library "liblttng-ust-fork.so" | |
413 | needs to be preloaded for the application (launch with e.g. | |
414 | LD_PRELOAD=liblttng-ust-fork.so appname). | |
415 | ||
416 | .fi | |
417 | ||
94c9c48d MD |
418 | .SH "CONTEXT" |
419 | ||
420 | .PP | |
421 | Context information can be prepended by the tracer before each, or some, | |
422 | events. The following context information is supported by LTTng-UST: | |
423 | .PP | |
424 | ||
425 | .PP | |
426 | .IP "vtid" | |
427 | Virtual thread ID: thread ID as seen from the point of view of the | |
428 | process namespace. | |
429 | .PP | |
430 | ||
431 | .PP | |
432 | .IP "vpid" | |
433 | Virtual process ID: process ID as seen from the point of view of the | |
434 | process namespace. | |
435 | .PP | |
436 | ||
f6df8626 PW |
437 | .PP |
438 | .IP "ip" | |
439 | Instruction pointer: Enables recording of the exact location where a tracepoint | |
440 | was emitted. Can be used to reverse-lookup the source location that caused the | |
441 | event to be emitted. | |
442 | .PP | |
443 | ||
94c9c48d MD |
444 | .PP |
445 | .IP "procname" | |
446 | Thread name, as set by exec() or prctl(). It is recommended that | |
447 | programs set their thread name with prctl() before hitting the first | |
448 | tracepoint for that thread. | |
449 | .PP | |
450 | ||
451 | .PP | |
452 | .IP "pthread_id" | |
453 | Pthread identifier. Can be used on architectures where pthread_t maps | |
454 | nicely to an unsigned long type. | |
455 | .PP | |
456 | ||
ce46717a | 457 | .SH "BASE ADDRESS STATEDUMP" |
f6df8626 PW |
458 | |
459 | .PP | |
460 | If an application that uses liblttng-ust.so becomes part of a session, | |
461 | information about its currently loaded shared objects will be traced to the | |
462 | session at session-enable time. To record this information, the following event | |
463 | needs to be enabled: | |
464 | .PP | |
465 | .IP "ust_baddr_statedump:soinfo" | |
466 | This event is used to trace a currently loaded shared object. The base address | |
467 | (where the dynamic linker has placed the shared object) is recorded in the | |
6d262185 MD |
468 | "baddr" field. The path to the shared object gets recorded in the |
469 | "sopath" field (as string). The file size of the loaded object (in | |
470 | bytes) is recorded to the "size" field and its time of last modification | |
471 | (in seconds since Epoch) is recorded in the "mtime" field. | |
f6df8626 | 472 | .PP |
6d262185 MD |
473 | If the event above is enabled, a series of "ust_baddr_statedump:soinfo" |
474 | events is recorded at session-enable time. It represents the state of | |
475 | currently loaded shared objects for the traced process. If this | |
476 | information gets combined with the lttng-ust-dl(3) instrumentation, all | |
477 | aspects of dynamic loading that are relevant for symbol and | |
478 | line number lookup are traced by LTTng. | |
f6df8626 | 479 | .PP |
eba411c6 MD |
480 | .SH "ENVIRONMENT VARIABLES" |
481 | ||
482 | .PP | |
483 | .IP "LTTNG_UST_DEBUG" | |
d14c063a | 484 | Activate liblttng-ust debug and error output. |
eba411c6 MD |
485 | .PP |
486 | .IP "LTTNG_UST_REGISTER_TIMEOUT" | |
487 | The environment variable "LTTNG_UST_REGISTER_TIMEOUT" can be used to | |
488 | specify how long the applications should wait for sessiond | |
489 | "registration done" command before proceeding to execute the main | |
490 | program. The default is 3000ms (3 seconds). The timeout value is | |
491 | specified in milliseconds. The value 0 means "don't wait". The value | |
9b6435af | 492 | \-1 means "wait forever". Setting this environment variable to 0 is |
eba411c6 MD |
493 | recommended for applications with time constraints on the process |
494 | startup time. | |
495 | .PP | |
ce46717a PW |
496 | .IP "LTTNG_UST_WITHOUT_BADDR_STATEDUMP" |
497 | Prevent liblttng-ust to perform a base-address statedump on session-enable. | |
f6df8626 | 498 | .PP |
eba411c6 MD |
499 | |
500 | .SH "SEE ALSO" | |
501 | ||
502 | .PP | |
d1eaa4d7 | 503 | lttng-gen-tp(1), lttng(1), babeltrace(1), lttng-ust-cyg-profile(3), |
f6df8626 | 504 | lttng-ust-dl(3), lttng-sessiond(8) |
eba411c6 | 505 | .PP |
ff42aeef MD |
506 | |
507 | .SH "COMPATIBILITY" | |
508 | ||
509 | .PP | |
510 | Older lttng-ust libraries reject more recent, and incompatible, probe | |
cf949d07 | 511 | providers. Newer lttng-ust libraries accept older probe providers, even |
ff42aeef MD |
512 | though some newer features might not be available with those providers. |
513 | .PP | |
514 | ||
eba411c6 MD |
515 | .SH "BUGS" |
516 | ||
517 | .PP | |
ff42aeef MD |
518 | LTTng-UST 2.0 and 2.1 lttng-ust libraries do not check for probe |
519 | provider version compatibility. This can lead to out-of-bound accesses | |
520 | when using a more recent probe provider with an older lttng-ust library. | |
521 | These error only trigger when tracing is active. This issue has been | |
522 | fixed in LTTng-UST 2.2. | |
eba411c6 MD |
523 | |
524 | If you encounter any issues or usability problem, please report it on | |
525 | our mailing list <lttng-dev@lists.lttng.org> to help improve this | |
526 | project. | |
527 | .SH "CREDITS" | |
528 | ||
529 | liblttng-ust is distributed under the GNU Lesser General Public License | |
530 | version 2.1. The headers are distributed under the MIT license. | |
531 | .PP | |
532 | See http://lttng.org for more information on the LTTng project. | |
533 | .PP | |
534 | Mailing list for support and development: <lttng-dev@lists.lttng.org>. | |
535 | .PP | |
536 | You can find us on IRC server irc.oftc.net (OFTC) in #lttng. | |
537 | .PP | |
538 | .SH "THANKS" | |
539 | ||
540 | Thanks to Ericsson for funding this work, providing real-life use-cases, | |
541 | and testing. | |
542 | ||
543 | Special thanks to Michel Dagenais and the DORSAL laboratory at | |
544 | Polytechnique de Montreal for the LTTng journey. | |
545 | .PP | |
546 | .SH "AUTHORS" | |
547 | ||
548 | .PP | |
549 | liblttng-ust was originally written by Mathieu Desnoyers, with additional | |
550 | contributions from various other people. It is currently maintained by | |
551 | Mathieu Desnoyers <mathieu.desnoyers@efficios.com>. | |
552 | .PP |