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3 | \begin_document |
4 | \begin_header |
5 | \textclass article |
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30 | \quotes_language english |
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32 | \papersides 1 |
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35 | \output_changes false |
36 | \author "" |
37 | \author "" |
38 | \end_header |
39 | |
40 | \begin_body |
41 | |
42 | \begin_layout Title |
43 | A Set of APIs for a Third-Generation Trace Viewer |
44 | \end_layout |
45 | |
46 | \begin_layout Author |
47 | \noindent |
48 | Pierre-Marc Fournier, Michel Dagenais, Mathieu Desnoyers |
49 | \newline |
50 | |
51 | \family typewriter |
52 | \size footnotesize |
53 | <pierre-marc.fournier _at_ polymtl.ca> |
54 | \family default |
55 | \size default |
56 | |
57 | \newline |
58 | |
59 | \newline |
60 | CASI Lab |
61 | \newline |
62 | École Polytechnique de Montréal |
63 | \newline |
64 | |
65 | \newline |
66 | WORK IN PROGRESS |
67 | \end_layout |
68 | |
69 | \begin_layout Section |
70 | Introduction |
71 | \end_layout |
72 | |
73 | \begin_layout Standard |
74 | This document proposes some APIs for a trace viewing and analysis infrastructure. |
75 | \end_layout |
76 | |
77 | \begin_layout Standard |
78 | Design choices were made based on the experience acquired by the design, |
79 | development and use of two previous generations of trace viewers, respectively |
80 | the Trace Visualizer from the Linux Trace Toolkit and its successor, the |
81 | LTTV from the LTTng tracing toolkit. |
82 | \end_layout |
83 | |
84 | \begin_layout Section |
85 | Goals |
86 | \end_layout |
87 | |
88 | \begin_layout Itemize |
89 | Provide an infrastructure for fast, interactive visualization and analysis |
90 | of huge traces (>10 GB) on standard workstations |
91 | \begin_inset Foot |
92 | status open |
93 | |
94 | \begin_layout Standard |
95 | Efficiency is of great importance. |
96 | It is tempting to think that as computers get faster, it will be possible |
97 | to run more complex analyses on traces in a shorter time. |
98 | In fact, the size of the traces grows as computers get more powerful, because |
99 | they do more operations than before in the same amount of time and therefore |
100 | generate more events. |
101 | The current tendency to parallelize systems is another factor that results |
102 | in bigger traces. |
103 | \end_layout |
104 | |
105 | \end_inset |
106 | |
107 | |
108 | \end_layout |
109 | |
110 | \begin_layout Itemize |
b71d449a |
111 | Allow efficient manipulation of traces that are larger than the system memory |
112 | \end_layout |
113 | |
114 | \begin_layout Itemize |
115 | Support processing of live traces |
1fde1b39 |
116 | \end_layout |
117 | |
118 | \begin_layout Itemize |
119 | Allow merging of traces of different formats |
120 | \end_layout |
121 | |
1fde1b39 |
122 | \begin_layout Itemize |
123 | Design with both command line utilities (C language) and graphical interfaces |
124 | (Java and others) in mind, sharing code and standardizing interfaces as |
125 | much as possible |
126 | \end_layout |
127 | |
128 | \begin_deeper |
129 | \begin_layout Standard |
130 | Both command-line interfaces and graphical interfaces have an important |
131 | role to play in trace analysis. |
132 | While graphical interfaces allow for complex views, command-line utilities |
133 | can be used quickly in more environments; they can also be more convenient |
134 | in some circumstances. |
135 | A good design should be such that they can share code and APIs. |
136 | \end_layout |
137 | |
138 | \end_deeper |
139 | \begin_layout Section |
140 | General aspects |
141 | \end_layout |
142 | |
143 | \begin_layout Itemize |
144 | All data structures must be accessed through API methods, in order to allow |
145 | for internal change without breaking compatibility. |
146 | \end_layout |
147 | |
1fde1b39 |
148 | \begin_layout Itemize |
4414440b |
149 | The APIs in this document are described as C functions and datatypes. |
b71d449a |
150 | When an operation applies to an abstraction that could be an object in |
4414440b |
151 | an object-oriented language, it is specified as the first argument of the |
152 | function. |
1fde1b39 |
153 | \end_layout |
154 | |
155 | \begin_layout Subsection |
4414440b |
156 | Time |
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157 | \end_layout |
158 | |
1fde1b39 |
159 | \begin_layout Standard |
4414440b |
160 | The framework needs to represent points in the time line and time ranges. |
161 | This is done by two data structures, respectively: |
1fde1b39 |
162 | \end_layout |
163 | |
164 | \begin_layout Itemize |
4414440b |
165 | struct trace_time |
1fde1b39 |
166 | \end_layout |
167 | |
168 | \begin_layout Itemize |
4414440b |
169 | struct trace_time_range |
1fde1b39 |
170 | \end_layout |
171 | |
1fde1b39 |
172 | \begin_layout Standard |
4414440b |
173 | The preferred representation for times is seconds. |
1fde1b39 |
174 | \end_layout |
175 | |
4414440b |
176 | \begin_layout Standard |
177 | Ranges are a span between two points in time. |
178 | They are represented as these two points. |
179 | One or both of them can have the special value |
180 | \emph on |
181 | infinity |
182 | \emph default |
183 | . |
1fde1b39 |
184 | \end_layout |
185 | |
b71d449a |
186 | \begin_layout Standard |
187 | Each time is accompanied by an uncertainty value. |
188 | \end_layout |
189 | |
1fde1b39 |
190 | \begin_layout Section |
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191 | Low level reading of traces |
1fde1b39 |
192 | \end_layout |
193 | |
194 | \begin_layout Subsection |
195 | Overview |
196 | \end_layout |
197 | |
b71d449a |
198 | \begin_layout Standard |
199 | This API presents a uniform way of accessing traces at a low level, that |
200 | is to access randomly the events of the trace in an physical-encoding-independa |
201 | nt way. |
202 | \end_layout |
203 | |
204 | \begin_layout Standard |
205 | \begin_inset Note Note |
206 | status open |
207 | |
1fde1b39 |
208 | \begin_layout Subsubsection |
209 | Timestamps |
210 | \end_layout |
211 | |
212 | \begin_layout Standard |
213 | Timestamps, at the framework level, should be in an architecture-independent |
214 | format. |
215 | One possibility would be to have them stored in seconds (with decimals). |
216 | Offsetting, if necessary, could be handled by the traceset (trace merging) |
217 | level. |
218 | An uncertainty value should accompany the timestamp. |
219 | Timestamps in cycles should be available if they are provided by the tracer. |
220 | \end_layout |
221 | |
b71d449a |
222 | \end_inset |
223 | |
224 | |
1fde1b39 |
225 | \end_layout |
226 | |
227 | \begin_layout Standard |
b71d449a |
228 | \begin_inset Note Note |
229 | status open |
1fde1b39 |
230 | |
231 | \begin_layout Subsubsection |
232 | Factory methods |
233 | \end_layout |
234 | |
235 | \begin_layout Itemize |
6e3755ba |
236 | void get_supported_formats(void) |
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237 | \end_layout |
238 | |
239 | \begin_deeper |
240 | \begin_layout Standard |
241 | Arguments: none |
242 | \end_layout |
243 | |
244 | \begin_layout Standard |
245 | Return: |
246 | \end_layout |
247 | |
248 | \begin_layout Itemize |
249 | a list of supported formats |
250 | \end_layout |
251 | |
252 | \end_deeper |
253 | \begin_layout Itemize |
254 | open_trace() |
255 | \end_layout |
256 | |
257 | \begin_deeper |
258 | \begin_layout Standard |
259 | Arguments: |
260 | \end_layout |
261 | |
262 | \begin_layout Itemize |
263 | trace URL |
264 | \end_layout |
265 | |
266 | \begin_deeper |
267 | \begin_layout Itemize |
268 | local file name |
269 | \end_layout |
270 | |
271 | \begin_layout Itemize |
272 | other special url to establish a network connection |
273 | \end_layout |
274 | |
275 | \begin_layout Itemize |
276 | etc... |
277 | \end_layout |
278 | |
279 | \end_deeper |
280 | \begin_layout Itemize |
281 | trace format (optional, for cases where auto detection would not work or |
282 | be ambiguous) |
283 | \end_layout |
284 | |
285 | \begin_layout Standard |
286 | Return: |
287 | \end_layout |
288 | |
289 | \begin_layout Itemize |
290 | a trace handle |
291 | \end_layout |
292 | |
b71d449a |
293 | \end_inset |
294 | |
295 | |
296 | \end_layout |
297 | |
298 | \begin_layout Subsection |
299 | Methods of the Low Level Trace Reading API |
1fde1b39 |
300 | \end_layout |
301 | |
302 | \begin_layout Itemize |
b71d449a |
303 | void close(struct trace *tr) |
1fde1b39 |
304 | \end_layout |
305 | |
b71d449a |
306 | \begin_deeper |
307 | \begin_layout Standard |
308 | Close the trace and unallocate all resources associated to this struct trace |
309 | including the handle. |
310 | After this call, tr is invalid and its memory is freed. |
311 | \end_layout |
312 | |
313 | \end_deeper |
1fde1b39 |
314 | \begin_layout Itemize |
b71d449a |
315 | struct event *current_event(struct trace *, struct cursor *cur) |
1fde1b39 |
316 | \end_layout |
317 | |
318 | \begin_deeper |
319 | \begin_layout Standard |
320 | Arguments: none |
321 | \end_layout |
322 | |
323 | \begin_layout Standard |
324 | Return: |
325 | \end_layout |
326 | |
327 | \begin_layout Itemize |
328 | the event currently pointed by the position pointer |
329 | \end_layout |
330 | |
b71d449a |
331 | \begin_layout Itemize |
332 | NULL, if current_event is called on a new cursor that is positioned before |
333 | the beginning of the trace |
334 | \end_layout |
335 | |
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336 | \end_deeper |
337 | \begin_layout Itemize |
b71d449a |
338 | int advance(struct trace *tr, struct trace_cursor *cur) |
1fde1b39 |
339 | \end_layout |
340 | |
341 | \begin_deeper |
342 | \begin_layout Standard |
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343 | Advance the cursor to the next event in the trace. |
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344 | \end_layout |
345 | |
346 | \begin_layout Standard |
b71d449a |
347 | Arguments: |
348 | \end_layout |
349 | |
350 | \begin_layout Itemize |
351 | tr: the trace |
352 | \end_layout |
353 | |
354 | \begin_layout Itemize |
355 | cur: the cursor that should be advanced |
1fde1b39 |
356 | \end_layout |
357 | |
358 | \begin_layout Standard |
b71d449a |
359 | Return value: |
1fde1b39 |
360 | \end_layout |
361 | |
362 | \begin_layout Itemize |
363 | The result: |
364 | \end_layout |
365 | |
366 | \begin_deeper |
367 | \begin_layout Itemize |
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368 | Success (TRACE_ADVANCE_OK) |
1fde1b39 |
369 | \end_layout |
370 | |
371 | \begin_layout Itemize |
b71d449a |
372 | The cursor was not advanced because the end of trace is reached (end of |
373 | a non-live trace or of a completed live trace) (TRACE_ADVANCE_END) |
1fde1b39 |
374 | \end_layout |
375 | |
376 | \begin_layout Itemize |
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377 | The cursor was not advanced because no new events are available at this |
378 | time (with a live trace that is still running) (TRACE_ADVANCE_TRY_AGAIN) |
1fde1b39 |
379 | \end_layout |
380 | |
381 | \end_deeper |
382 | \end_deeper |
383 | \begin_layout Itemize |
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384 | int seek_time(struct trace *tr, struct trace_cursor *cur, struct trace_time |
385 | time) |
1fde1b39 |
386 | \end_layout |
387 | |
388 | \begin_deeper |
389 | \begin_layout Standard |
390 | Arguments: |
391 | \end_layout |
392 | |
393 | \begin_layout Itemize |
b71d449a |
394 | tr: the trace that should be seeked |
395 | \end_layout |
396 | |
397 | \begin_layout Itemize |
398 | cur: the cursor to seek |
399 | \end_layout |
400 | |
401 | \begin_layout Itemize |
402 | time: the time to seek to |
1fde1b39 |
403 | \end_layout |
404 | |
405 | \begin_layout Standard |
b71d449a |
406 | Return: |
407 | \end_layout |
408 | |
409 | \begin_layout Itemize |
410 | 0: success |
411 | \end_layout |
412 | |
413 | \begin_layout Itemize |
414 | != 0: time out of range |
1fde1b39 |
415 | \end_layout |
416 | |
417 | \end_deeper |
418 | \begin_layout Itemize |
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419 | struct trace_cursor *trace_new_cursor(struct trace *tr) |
1fde1b39 |
420 | \end_layout |
421 | |
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422 | \begin_deeper |
423 | \begin_layout Standard |
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424 | Return a new cursor associated to the trace. |
425 | The position of this new cursor is just before the first event, therefore |
426 | advance() must be called before reading the first event. |
6e3755ba |
427 | \end_layout |
428 | |
429 | \end_deeper |
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430 | \begin_layout Itemize |
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431 | struct trace_cursor *trace_cursor_copy(struct trace_cursor *cur) |
1fde1b39 |
432 | \end_layout |
433 | |
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434 | \begin_deeper |
435 | \begin_layout Standard |
436 | Copy a cursor. |
437 | \end_layout |
438 | |
439 | \begin_layout Standard |
440 | Arguments: |
441 | \end_layout |
442 | |
443 | \begin_layout Itemize |
444 | cur: the cursor to copy |
445 | \end_layout |
446 | |
447 | \begin_layout Standard |
448 | Return value: |
449 | \end_layout |
450 | |
451 | \begin_layout Itemize |
452 | a new cursor that is at the same location as cur |
453 | \end_layout |
454 | |
455 | \end_deeper |
456 | \begin_layout Itemize |
457 | void trace_cursor_destroy(struct trace_cursor *cur) |
458 | \end_layout |
459 | |
460 | \begin_deeper |
461 | \begin_layout Standard |
462 | Free all resources associated to a cursor. |
463 | After this call, cur is invalid. |
464 | \end_layout |
465 | |
466 | \begin_layout Standard |
467 | Arguments: |
468 | \end_layout |
469 | |
1fde1b39 |
470 | \begin_layout Itemize |
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471 | cur: the cursor to destroy |
1fde1b39 |
472 | \end_layout |
473 | |
b71d449a |
474 | \end_deeper |
1fde1b39 |
475 | \begin_layout Itemize |
6e3755ba |
476 | struct trace_time get_time_start(struct trace *tr) |
1fde1b39 |
477 | \end_layout |
478 | |
479 | \begin_deeper |
480 | \begin_layout Standard |
b71d449a |
481 | Arguments: |
482 | \end_layout |
483 | |
484 | \begin_layout Itemize |
485 | tr: the trace |
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486 | \end_layout |
487 | |
488 | \begin_layout Standard |
489 | Return: |
490 | \end_layout |
491 | |
492 | \begin_layout Itemize |
493 | the timestamp of the first event in the trace |
494 | \end_layout |
495 | |
496 | \end_deeper |
497 | \begin_layout Itemize |
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498 | struct trace_time get_time_end(struct trace *tr) |
1fde1b39 |
499 | \end_layout |
500 | |
501 | \begin_deeper |
502 | \begin_layout Standard |
503 | Arguments: none |
504 | \end_layout |
505 | |
506 | \begin_layout Standard |
507 | Return: |
508 | \end_layout |
509 | |
510 | \begin_layout Itemize |
511 | the timestamp of the last event in the trace |
512 | \end_layout |
513 | |
514 | \end_deeper |
515 | \begin_layout Itemize |
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516 | register_callback_new_event(struct trace *tr, struct trace_time after, void |
b71d449a |
517 | (*cb)(struct trace *)) |
1fde1b39 |
518 | \end_layout |
519 | |
520 | \begin_deeper |
521 | \begin_layout Standard |
522 | Register a callback that is called when a new event becomes available in |
523 | a live trace. |
524 | It is also called when the live trace ends. |
525 | \end_layout |
526 | |
527 | \begin_layout Standard |
528 | Arguments: |
529 | \end_layout |
530 | |
531 | \begin_layout Itemize |
b71d449a |
532 | after (timestamp) : call only if the timestamp of the event is later than |
533 | |
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534 | \emph on |
535 | after |
536 | \end_layout |
537 | |
538 | \begin_layout Itemize |
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539 | cb: the callback function |
1fde1b39 |
540 | \begin_inset Note Note |
541 | status open |
542 | |
543 | \begin_layout Standard |
544 | specify its args and return val |
545 | \end_layout |
546 | |
547 | \end_inset |
548 | |
549 | |
550 | \end_layout |
551 | |
552 | \begin_layout Standard |
553 | Return: |
554 | \end_layout |
555 | |
556 | \begin_layout Itemize |
557 | Result (success or failure) |
558 | \end_layout |
559 | |
560 | \end_deeper |
b71d449a |
561 | \begin_layout Section |
562 | High level reading of traces |
563 | \end_layout |
564 | |
565 | \begin_layout Standard |
566 | When reading/analyzing/viewing several traces of heterogenous types, these |
567 | traces are read by translator modules, which export the Low Level Trace |
568 | Reading API. |
569 | The traceset service then uses this API to read each of these traces individual |
570 | ly, then merge them. |
571 | It may apply timestamp offsetting or other synchronization techniques. |
572 | To allow views and analyses to access events, it in turn exports the High |
573 | Level Trace Reading API. |
1fde1b39 |
574 | \end_layout |
575 | |
576 | \begin_layout Standard |
577 | The goal of this API is to provide a uniform way for analyses and views |
b71d449a |
578 | to obtain large sets of trace events from a traceset (merge of many traces |
579 | or a single trace). |
580 | \end_layout |
581 | |
582 | \begin_layout Subsection |
583 | Methods of the high-level trace reading API |
1fde1b39 |
584 | \end_layout |
585 | |
586 | \begin_layout Itemize |
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587 | struct request_handle *traceset_new_event_request(struct traceset *tr, struct |
588 | trace_time t1, struct trace_time t2, struct event_filter *filter, void |
589 | (*cb)(void *data, ), void *data) |
1fde1b39 |
590 | \end_layout |
591 | |
592 | \begin_deeper |
593 | \begin_layout Standard |
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594 | Request a range of events |
1fde1b39 |
595 | \end_layout |
596 | |
4414440b |
597 | \begin_layout Standard |
598 | Arguments: |
1fde1b39 |
599 | \end_layout |
600 | |
601 | \begin_layout Itemize |
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602 | tr: the traceset |
1fde1b39 |
603 | \end_layout |
604 | |
605 | \begin_layout Itemize |
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606 | t1: start timestamp |
1fde1b39 |
607 | \end_layout |
608 | |
609 | \begin_layout Itemize |
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610 | t2: stop timestamp (special value for infinity, for live traces) |
1fde1b39 |
611 | \end_layout |
612 | |
613 | \begin_layout Itemize |
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614 | filter: filter with complex expressions |
1fde1b39 |
615 | \end_layout |
616 | |
617 | \begin_layout Itemize |
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618 | data: private pointer to be passed to the callback |
1fde1b39 |
619 | \end_layout |
620 | |
621 | \begin_layout Standard |
622 | Return: |
623 | \end_layout |
624 | |
625 | \begin_layout Itemize |
626 | handle to the request for cancelling it |
627 | \end_layout |
628 | |
629 | \end_deeper |
630 | \begin_layout Itemize |
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631 | void event_request_cancel(struct request_handle *req) |
1fde1b39 |
632 | \end_layout |
633 | |
634 | \begin_deeper |
b71d449a |
635 | \begin_layout Standard |
636 | Cancel a request. |
637 | \end_layout |
638 | |
1fde1b39 |
639 | \begin_layout Standard |
640 | Arguments: |
641 | \end_layout |
642 | |
643 | \begin_layout Itemize |
4414440b |
644 | req: the handle to the request |
1fde1b39 |
645 | \end_layout |
646 | |
647 | \end_deeper |
648 | \begin_layout Subsection |
649 | State management |
650 | \end_layout |
651 | |
4414440b |
652 | \begin_layout Standard |
653 | States are key/value pairs associated with a time range. |
654 | Keys can be (and generally are) duplicated as long as they do not apply |
655 | to overlapping ranges. |
656 | \end_layout |
657 | |
658 | \begin_layout Standard |
659 | Keys are character strings. |
660 | \end_layout |
661 | |
662 | \begin_layout Standard |
663 | Values may be of various types: |
664 | \end_layout |
665 | |
666 | \begin_layout Itemize |
667 | string |
668 | \end_layout |
669 | |
670 | \begin_layout Itemize |
671 | uint32 |
672 | \end_layout |
673 | |
674 | \begin_layout Itemize |
675 | int32 |
676 | \end_layout |
677 | |
678 | \begin_layout Itemize |
679 | blob (binary block of arbitrary length) |
680 | \end_layout |
681 | |
682 | \begin_layout Itemize |
683 | float32 |
684 | \end_layout |
685 | |
686 | \begin_layout Itemize |
687 | float64 |
688 | \end_layout |
689 | |
690 | \begin_layout Standard |
691 | The state information must be persistent between executions of the framework. |
692 | \end_layout |
693 | |
694 | \begin_layout Standard |
695 | It is possible to assign a state to the range -infinity..infinity to indicate |
b71d449a |
696 | that it is global to the trace. |
4414440b |
697 | \end_layout |
698 | |
699 | \begin_layout Standard |
700 | The key names should be hierarchical. |
701 | \end_layout |
702 | |
1fde1b39 |
703 | \begin_layout Subsubsection |
704 | State accessing API |
705 | \end_layout |
706 | |
707 | \begin_layout Itemize |
4414440b |
708 | struct state_value *state_get_value_at_time(char *key, struct trace_time |
709 | time) |
1fde1b39 |
710 | \end_layout |
711 | |
712 | \begin_deeper |
4414440b |
713 | \begin_layout Standard |
714 | Request the value of a given key at a point in time |
715 | \end_layout |
716 | |
1fde1b39 |
717 | \begin_layout Standard |
718 | Arguments: |
719 | \end_layout |
720 | |
721 | \begin_layout Itemize |
4414440b |
722 | var: the state variables (string) |
723 | \end_layout |
724 | |
725 | \begin_layout Itemize |
726 | time: the timestamp |
727 | \end_layout |
728 | |
729 | \begin_layout Standard |
730 | Return value: |
1fde1b39 |
731 | \end_layout |
732 | |
733 | \begin_layout Itemize |
4414440b |
734 | The state value |
1fde1b39 |
735 | \end_layout |
736 | |
737 | \end_deeper |
738 | \begin_layout Itemize |
4414440b |
739 | struct state_value_range **state_get_values_in_range(char *key, struct state_val |
740 | ue *val, struct trace_time_range range) |
741 | \end_layout |
742 | |
743 | \begin_deeper |
744 | \begin_layout Standard |
1fde1b39 |
745 | Request all the states changes of a given set of state variables between |
746 | two time indexes |
747 | \end_layout |
748 | |
1fde1b39 |
749 | \begin_layout Standard |
750 | Arguments: |
751 | \end_layout |
752 | |
753 | \begin_layout Itemize |
4414440b |
754 | key: the key |
1fde1b39 |
755 | \end_layout |
756 | |
757 | \begin_layout Itemize |
4414440b |
758 | range: the time range |
1fde1b39 |
759 | \end_layout |
760 | |
4414440b |
761 | \end_deeper |
1fde1b39 |
762 | \begin_layout Itemize |
4414440b |
763 | Other functions for getting values for a set of keys at once? |
1fde1b39 |
764 | \end_layout |
765 | |
1fde1b39 |
766 | \begin_layout Subsubsection |
767 | State setting API |
768 | \end_layout |
769 | |
4414440b |
770 | \begin_layout Itemize |
771 | set a particular state |
772 | \end_layout |
773 | |
774 | \begin_layout Itemize |
775 | delete some states |
776 | \end_layout |
777 | |
1fde1b39 |
778 | \begin_layout Section |
779 | Describing event types |
780 | \end_layout |
781 | |
782 | \begin_layout Subsection |
783 | Overview |
784 | \end_layout |
785 | |
786 | \begin_layout Standard |
787 | Because tracepoints may be created dynamically, information about the descriptio |
788 | n of events is just as dynamic. |
789 | In this context, one simple way to communicate the event description informatio |
790 | n to upper layers would be to send them as events, as it is done in recent |
791 | versions of LTTV. |
792 | The core events used to describe other events are the only ones whose descripti |
793 | on is hardcoded in the framework. |
794 | \end_layout |
795 | |
796 | \begin_layout Standard |
797 | These event-type-describing events could then be received and interpreted |
4414440b |
798 | by the Event Description Service, which would be a client to the high-level |
799 | tracing API at the same level as normal views and analyses. |
1fde1b39 |
800 | It would store the information and allow the other views and analyses to |
801 | access it via this API. |
802 | \end_layout |
803 | |
4414440b |
804 | \begin_layout Standard |
805 | Each event has a timestamp, a name and arguments of various types. |
806 | The framework should support the following types: |
807 | \end_layout |
808 | |
809 | \begin_layout Itemize |
810 | uint32 |
811 | \end_layout |
812 | |
813 | \begin_layout Itemize |
814 | uint64 |
815 | \end_layout |
816 | |
817 | \begin_layout Itemize |
818 | int32 |
819 | \end_layout |
820 | |
821 | \begin_layout Itemize |
822 | int64 |
823 | \end_layout |
824 | |
825 | \begin_layout Itemize |
826 | string |
827 | \end_layout |
828 | |
1fde1b39 |
829 | \begin_layout Subsection |
830 | Events-describing events |
831 | \end_layout |
832 | |
833 | \begin_layout Itemize |
834 | Event type declaration event |
835 | \end_layout |
836 | |
837 | \begin_deeper |
838 | \begin_layout Standard |
839 | Announce the existence of an event type |
840 | \end_layout |
841 | |
842 | \begin_layout Itemize |
843 | event type name |
844 | \end_layout |
845 | |
846 | \end_deeper |
847 | \begin_layout Itemize |
848 | Argument declaration event |
849 | \end_layout |
850 | |
851 | \begin_deeper |
852 | \begin_layout Standard |
853 | Announce the existence of an event argument |
854 | \end_layout |
855 | |
856 | \begin_layout Itemize |
857 | event type name |
858 | \end_layout |
859 | |
860 | \begin_layout Itemize |
861 | name |
862 | \end_layout |
863 | |
864 | \begin_layout Itemize |
865 | type |
866 | \end_layout |
867 | |
868 | \end_deeper |
869 | \begin_layout Itemize |
870 | Event destruction |
871 | \end_layout |
872 | |
873 | \begin_deeper |
874 | \begin_layout Standard |
875 | Announce that an event type ceased to exist |
876 | \end_layout |
877 | |
878 | \begin_layout Itemize |
879 | event type name |
880 | \end_layout |
881 | |
882 | \end_deeper |
883 | \begin_layout Subsection |
884 | Event type description API |
885 | \end_layout |
886 | |
4414440b |
887 | \begin_layout Standard |
888 | The event type description service provides the following functions. |
889 | \end_layout |
890 | |
1fde1b39 |
891 | \begin_layout Itemize |
4414440b |
892 | GArray<struct event_type *> *traceset_get_all_event_types(struct traceset |
893 | *ts) |
894 | \end_layout |
895 | |
896 | \begin_deeper |
897 | \begin_layout Standard |
1fde1b39 |
898 | Get the list of all the event types |
899 | \end_layout |
900 | |
4414440b |
901 | \begin_layout Standard |
902 | Arguments: |
903 | \end_layout |
904 | |
1fde1b39 |
905 | \begin_layout Itemize |
4414440b |
906 | ts: the traceset of which we want the event types |
907 | \end_layout |
908 | |
909 | \begin_layout Standard |
910 | Return value: |
911 | \end_layout |
912 | |
913 | \begin_layout Itemize |
914 | A GArray of of struct event_type. |
915 | The GArray must be gfree()'d by the caller when it is done reading it. |
916 | \end_layout |
917 | |
918 | \end_deeper |
919 | \begin_layout Itemize |
920 | struct event_type *traceset_get_event_type_by_name(struct traceset *ts, |
921 | char *name) |
922 | \end_layout |
923 | |
924 | \begin_deeper |
925 | \begin_layout Standard |
1fde1b39 |
926 | Find an event type by name |
927 | \end_layout |
928 | |
4414440b |
929 | \begin_layout Standard |
930 | Arguments: |
931 | \end_layout |
932 | |
1fde1b39 |
933 | \begin_layout Itemize |
4414440b |
934 | ts: the traceset of which we want the event type |
1fde1b39 |
935 | \end_layout |
936 | |
937 | \begin_layout Itemize |
4414440b |
938 | name: the name of the of the event type we are looking for |
939 | \end_layout |
940 | |
941 | \begin_layout Standard |
942 | Return value: |
1fde1b39 |
943 | \end_layout |
944 | |
945 | \begin_layout Itemize |
4414440b |
946 | A pointer to the event type (must not be free'd) or NULL if not found |
947 | \end_layout |
948 | |
949 | \end_deeper |
950 | \begin_layout Itemize |
951 | GArray<struct event arg *> *event_type_get_all_args(struct event_type *evtype) |
952 | \end_layout |
953 | |
954 | \begin_deeper |
955 | \begin_layout Standard |
956 | Get the list of arguments of an event |
957 | \end_layout |
958 | |
959 | \begin_layout Standard |
960 | Arguments: |
1fde1b39 |
961 | \end_layout |
962 | |
963 | \begin_layout Itemize |
4414440b |
964 | eventype: the event type of which we want the arguments |
965 | \end_layout |
966 | |
967 | \begin_layout Standard |
968 | Return value: |
1fde1b39 |
969 | \end_layout |
970 | |
971 | \begin_layout Itemize |
4414440b |
972 | A GArray of struct event_args. |
973 | The GArray must be gfree()'d by the caller when it is done reading it. |
1fde1b39 |
974 | \end_layout |
975 | |
4414440b |
976 | \end_deeper |
1fde1b39 |
977 | \begin_layout Itemize |
4414440b |
978 | struct event_arg *event_type_get_arg_by_name(struct event_type *evtype) |
1fde1b39 |
979 | \end_layout |
980 | |
4414440b |
981 | \begin_deeper |
982 | \begin_layout Standard |
983 | Find an argument by name |
984 | \end_layout |
985 | |
986 | \end_deeper |
1fde1b39 |
987 | \begin_layout Itemize |
4414440b |
988 | Functions for accessing struct event_arg fields |
1fde1b39 |
989 | \end_layout |
990 | |
991 | \begin_layout Section |
992 | Inspecting events |
993 | \end_layout |
994 | |
995 | \begin_layout Subsection |
996 | Overview |
997 | \end_layout |
998 | |
999 | \begin_layout Standard |
1000 | Events contain the following information. |
1001 | \end_layout |
1002 | |
1003 | \begin_layout Itemize |
1004 | Timestamp |
1005 | \end_layout |
1006 | |
1007 | \begin_layout Itemize |
4414440b |
1008 | Event type identifier - an event id (integer) - hidden to the API users, |
1009 | manipulated as pointers/references to struct event_type |
1010 | \end_layout |
1011 | |
1012 | \begin_layout Itemize |
1013 | A reference to the trace it was in |
1014 | \end_layout |
1015 | |
1016 | \begin_layout Subsection |
1017 | Event inspecting API |
1018 | \end_layout |
1019 | |
1020 | \begin_layout Itemize |
1021 | struct event_type *event_get_type(struct traceset *ts, struct event *ev) |
1fde1b39 |
1022 | \end_layout |
1023 | |
1024 | \begin_deeper |
1025 | \begin_layout Standard |
4414440b |
1026 | get the event type corresponding to an event |
1fde1b39 |
1027 | \end_layout |
1028 | |
4414440b |
1029 | \begin_layout Standard |
1030 | Arguments: |
1fde1b39 |
1031 | \end_layout |
1032 | |
1033 | \begin_layout Itemize |
4414440b |
1034 | ts: |
1fde1b39 |
1035 | \end_layout |
1036 | |
1fde1b39 |
1037 | \begin_layout Itemize |
4414440b |
1038 | ev: |
1fde1b39 |
1039 | \end_layout |
1040 | |
4414440b |
1041 | \begin_layout Standard |
1042 | Return value: |
1fde1b39 |
1043 | \end_layout |
1044 | |
1045 | \begin_layout Itemize |
4414440b |
1046 | The event type or NULL if no information |
1047 | \end_layout |
1048 | |
1049 | \end_deeper |
1050 | \begin_layout Itemize |
1051 | struct trace_time event_get_time(struct event *ev) |
1052 | \end_layout |
1053 | |
1054 | \begin_deeper |
1055 | \begin_layout Standard |
1056 | get the event time |
1fde1b39 |
1057 | \end_layout |
1058 | |
4414440b |
1059 | \end_deeper |
1fde1b39 |
1060 | \begin_layout Itemize |
4414440b |
1061 | struct trace *event_get_trace(struct event *ev) |
1fde1b39 |
1062 | \end_layout |
1063 | |
1064 | \begin_layout Itemize |
4414440b |
1065 | get the name of the machine on which the event occured or other location |
1066 | information |
1fde1b39 |
1067 | \end_layout |
1068 | |
1069 | \begin_layout Itemize |
1070 | get information on the type of tracing technology that was used |
1071 | \end_layout |
1072 | |
1073 | \begin_layout Itemize |
1074 | get the corresponding tracepoint (machine/tracing technology/name/location |
1075 | in code(if available)) |
1076 | \end_layout |
1077 | |
4414440b |
1078 | \begin_layout Itemize |
1079 | uint32 event_read_arg_uint32(struct event *ev, struct event_arg *arg) |
1080 | \end_layout |
1081 | |
1082 | \begin_layout Itemize |
1083 | int32 event_read_arg_int32(struct event *ev, struct event_arg *arg) |
1084 | \end_layout |
1085 | |
1086 | \begin_layout Itemize |
1087 | uint64 event_read_arg_uint64(struct event *ev, struct event_arg *arg) |
1088 | \end_layout |
1089 | |
1090 | \begin_layout Itemize |
1091 | int64 event_read_arg_int64(struct event *ev, struct event_arg *arg) |
1092 | \end_layout |
1093 | |
1094 | \begin_layout Itemize |
1095 | float32 event_read_arg_float32(struct event *ev, struct event_arg *arg) |
1096 | \end_layout |
1097 | |
1098 | \begin_layout Itemize |
1099 | float64 event_read_arg_float64(struct event *ev, struct event_arg *arg) |
1100 | \end_layout |
1101 | |
1102 | \begin_layout Section |
1103 | Filtering events |
1104 | \end_layout |
1105 | |
1106 | \begin_layout Standard |
1107 | A filtering API is proposed. |
1108 | \end_layout |
1109 | |
1110 | \begin_layout Section |
1111 | Controlling the tracing of a system |
1112 | \end_layout |
1113 | |
1114 | \begin_layout Subsection |
1115 | Overview |
1116 | \end_layout |
1117 | |
1118 | \begin_layout Standard |
1119 | The goal of this API is to provide a portable way of controlling tracing |
1120 | of heterogenous systems. |
1121 | \end_layout |
1122 | |
1123 | \begin_layout Standard |
1124 | It should enable to do the following actions. |
1125 | \end_layout |
1126 | |
1127 | \begin_layout Itemize |
1128 | Set the parameters of a trace (channels, buffering, destination of data |
1129 | (file, network, process)...) |
1130 | \end_layout |
1131 | |
1132 | \begin_layout Itemize |
1133 | Control the recording of events (start, stop, pause the trace) |
1134 | \end_layout |
1135 | |
1136 | \begin_layout Itemize |
1137 | Create tracepoints (on dynamic tracers) and control which tracepoints are |
1138 | activated (some may be at trace level, others might only permit system |
1139 | level) |
1140 | \end_layout |
1141 | |
1142 | \begin_layout Subsection |
1143 | Trace control API |
1144 | \end_layout |
1145 | |
1146 | \begin_layout Itemize |
1147 | List the static tracepoints available on a system |
1148 | \end_layout |
1149 | |
1150 | \begin_deeper |
1151 | \begin_layout Standard |
1152 | These may be static tracepoints (active or inactive) or dynamic tracepoints |
1153 | (active or proposed). |
1154 | \end_layout |
1155 | |
1156 | \end_deeper |
1157 | \begin_layout Itemize |
1158 | Add a new dynamic tracepoint |
1159 | \end_layout |
1160 | |
1161 | \begin_layout Itemize |
1162 | Activate a tracepoint |
1163 | \end_layout |
1164 | |
1165 | \begin_layout Itemize |
1166 | Deactivate a tracepoint |
1167 | \end_layout |
1168 | |
1169 | \begin_layout Itemize |
1170 | List available probes |
1171 | \end_layout |
1172 | |
1173 | \begin_layout Itemize |
1174 | Connect a probe to a tracepoint |
1175 | \end_layout |
1176 | |
1177 | \begin_layout Itemize |
1178 | Start tracing |
1179 | \end_layout |
1180 | |
1181 | \begin_layout Itemize |
1182 | Stop tracing |
1183 | \end_layout |
1184 | |
1185 | \begin_layout Itemize |
1186 | \begin_inset Note Greyedout |
1187 | status open |
1188 | |
1189 | \begin_layout Standard |
1190 | others missing... |
1191 | \end_layout |
1192 | |
1193 | \end_inset |
1194 | |
1195 | |
1196 | \end_layout |
1197 | |
1fde1b39 |
1198 | \end_body |
1199 | \end_document |