Add base integer attribute for pretty-print
[ctf.git] / common-trace-format-proposal.txt
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5ba9f198 1
4767a9e7 2RFC: Common Trace Format (CTF) Proposal (pre-v1.7)
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3
4Mathieu Desnoyers, EfficiOS Inc.
5
6The goal of the present document is to propose a trace format that suits the
cc089c3a 7needs of the embedded, telecom, high-performance and kernel communities. It is
5ba9f198 8based on the Common Trace Format Requirements (v1.4) document. It is designed to
cc089c3a 9allow traces to be natively generated by the Linux kernel, Linux user-space
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10applications written in C/C++, and hardware components. One major element of
11CTF is the Trace Stream Description Language (TSDL) which flexibility
12enables description of various binary trace stream layouts.
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13
14The latest version of this document can be found at:
15
16 git tree: git://git.efficios.com/ctf.git
17 gitweb: http://git.efficios.com/?p=ctf.git
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18
19A reference implementation of a library to read and write this trace format is
20being implemented within the BabelTrace project, a converter between trace
21formats. The development tree is available at:
22
23 git tree: git://git.efficios.com/babeltrace.git
24 gitweb: http://git.efficios.com/?p=babeltrace.git
25
26
271. Preliminary definitions
28
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29 - Event Trace: An ordered sequence of events.
30 - Event Stream: An ordered sequence of events, containing a subset of the
31 trace event types.
32 - Event Packet: A sequence of physically contiguous events within an event
33 stream.
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34 - Event: This is the basic entry in a trace. (aka: a trace record).
35 - An event identifier (ID) relates to the class (a type) of event within
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36 an event stream.
37 e.g. event: irq_entry.
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38 - An event (or event record) relates to a specific instance of an event
39 class.
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40 e.g. event: irq_entry, at time X, on CPU Y
41 - Source Architecture: Architecture writing the trace.
42 - Reader Architecture: Architecture reading the trace.
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43
44
452. High-level representation of a trace
46
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47A trace is divided into multiple event streams. Each event stream contains a
48subset of the trace event types.
5ba9f198 49
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50The final output of the trace, after its generation and optional transport over
51the network, is expected to be either on permanent or temporary storage in a
52virtual file system. Because each event stream is appended to while a trace is
53being recorded, each is associated with a separate file for output. Therefore,
54a stored trace can be represented as a directory containing one file per stream.
5ba9f198 55
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56Meta-data description associated with the trace contains information on
57trace event types expressed in the Trace Stream Description Language
58(TSDL). This language describes:
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59
60- Trace version.
61- Types available.
6672e9e1 62- Per-trace event header description.
3bf79539 63- Per-stream event header description.
6672e9e1 64- Per-stream event context description.
5ba9f198 65- Per-event
3bf79539 66 - Event type to stream mapping.
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67 - Event type to name mapping.
68 - Event type to ID mapping.
6672e9e1 69 - Event context description.
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70 - Event fields description.
71
72
3bf79539 733. Event stream
5ba9f198 74
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75An event stream can be divided into contiguous event packets of variable
76size. These subdivisions have a variable size. An event packet can
77contain a certain amount of padding at the end. The stream header is
78repeated at the beginning of each event packet. The rationale for the
79event stream design choices is explained in Appendix B. Stream Header
80Rationale.
5ba9f198 81
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82The event stream header will therefore be referred to as the "event packet
83header" throughout the rest of this document.
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84
85
864. Types
87
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88Types are organized as type classes. Each type class belong to either of two
89kind of types: basic types or compound types.
90
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914.1 Basic types
92
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93A basic type is a scalar type, as described in this section. It includes
94integers, GNU/C bitfields, enumerations, and floating point values.
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95
964.1.1 Type inheritance
97
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98Type specifications can be inherited to allow deriving types from a
99type class. For example, see the uint32_t named type derived from the "integer"
100type class below ("Integers" section). Types have a precise binary
101representation in the trace. A type class has methods to read and write these
102types, but must be derived into a type to be usable in an event field.
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103
1044.1.2 Alignment
105
106We define "byte-packed" types as aligned on the byte size, namely 8-bit.
107We define "bit-packed" types as following on the next bit, as defined by the
370eae99 108"Integers" section.
5ba9f198 109
6672e9e1 110Each basic type must specify its alignment, in bits. Examples of
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111possible alignments are: bit-packed (align = 1), byte-packed (align =
1128), or word-aligned (e.g. align = 32 or align = 64). The choice depends
113on the architecture preference and compactness vs performance trade-offs
114of the implementation. Architectures providing fast unaligned write
115byte-packed basic types to save space, aligning each type on byte
116boundaries (8-bit). Architectures with slow unaligned writes align types
117on specific alignment values. If no specific alignment is declared for a
118type, it is assumed to be bit-packed for integers with size not multiple
119of 8 bits and for gcc bitfields. All other basic types are byte-packed
120by default. It is however recommended to always specify the alignment
121explicitly. Alignment values must be power of two. Compound types are
122aligned as specified in their individual specification.
5ba9f198 123
6672e9e1 124TSDL meta-data attribute representation of a specific alignment:
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125
126 align = value; /* value in bits */
127
1284.1.3 Byte order
129
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130By default, the native endianness of the source architecture the trace is used.
131Byte order can be overridden for a basic type by specifying a "byte_order"
132attribute. Typical use-case is to specify the network byte order (big endian:
133"be") to save data captured from the network into the trace without conversion.
134If not specified, the byte order is native.
5ba9f198 135
6672e9e1 136TSDL meta-data representation:
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137
138 byte_order = native OR network OR be OR le; /* network and be are aliases */
139
1404.1.4 Size
141
142Type size, in bits, for integers and floats is that returned by "sizeof()" in C
143multiplied by CHAR_BIT.
144We require the size of "char" and "unsigned char" types (CHAR_BIT) to be fixed
145to 8 bits for cross-endianness compatibility.
146
6672e9e1 147TSDL meta-data representation:
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148
149 size = value; (value is in bits)
150
1514.1.5 Integers
152
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153Signed integers are represented in two-complement. Integer alignment,
154size, signedness and byte ordering are defined in the TSDL meta-data.
155Integers aligned on byte size (8-bit) and with length multiple of byte
156size (8-bit) correspond to the C99 standard integers. In addition,
157integers with alignment and/or size that are _not_ a multiple of the
158byte size are permitted; these correspond to the C99 standard bitfields,
159with the added specification that the CTF integer bitfields have a fixed
160binary representation. A MIT-licensed reference implementation of the
161CTF portable bitfields is available at:
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162
163 http://git.efficios.com/?p=babeltrace.git;a=blob;f=include/babeltrace/bitfield.h
164
165Binary representation of integers:
166
167- On little and big endian:
168 - Within a byte, high bits correspond to an integer high bits, and low bits
169 correspond to low bits.
170- On little endian:
171 - Integer across multiple bytes are placed from the less significant to the
172 most significant.
173 - Consecutive integers are placed from lower bits to higher bits (even within
174 a byte).
175- On big endian:
176 - Integer across multiple bytes are placed from the most significant to the
177 less significant.
178 - Consecutive integers are placed from higher bits to lower bits (even within
179 a byte).
180
181This binary representation is derived from the bitfield implementation in GCC
182for little and big endian. However, contrary to what GCC does, integers can
6672e9e1 183cross units boundaries (no padding is required). Padding can be explicitly
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184added (see 4.1.6 GNU/C bitfields) to follow the GCC layout if needed.
185
6672e9e1 186TSDL meta-data representation:
5ba9f198 187
80fd2569 188 integer {
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189 signed = true OR false; /* default false */
190 byte_order = native OR network OR be OR le; /* default native */
191 size = value; /* value in bits, no default */
192 align = value; /* value in bits */
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193 /* based used for pretty-printing output, default: decimal. */
194 base = decimal OR dec OR OR d OR i OR u OR 10 OR hexadecimal OR hex OR x OR X OR p OR 16
195 OR octal OR oct OR o OR 8 OR binary OR b OR 2;
2152348f 196 }
5ba9f198 197
80fd2569 198Example of type inheritance (creation of a uint32_t named type):
5ba9f198 199
359894ac 200typealias integer {
9e4e34e9 201 size = 32;
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202 signed = false;
203 align = 32;
38b8da21 204} := uint32_t;
5ba9f198 205
80fd2569 206Definition of a named 5-bit signed bitfield:
5ba9f198 207
359894ac 208typealias integer {
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209 size = 5;
210 signed = true;
211 align = 1;
38b8da21 212} := int5_t;
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213
2144.1.6 GNU/C bitfields
215
216The GNU/C bitfields follow closely the integer representation, with a
217particularity on alignment: if a bitfield cannot fit in the current unit, the
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218unit is padded and the bitfield starts at the following unit. The unit size is
219defined by the size of the type "unit_type".
5ba9f198 220
6672e9e1 221TSDL meta-data representation:
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222
223 unit_type name:size:
224
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225As an example, the following structure declared in C compiled by GCC:
226
227struct example {
228 short a:12;
229 short b:5;
230};
231
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232The example structure is aligned on the largest element (short). The second
233bitfield would be aligned on the next unit boundary, because it would not fit in
234the current unit.
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235
2364.1.7 Floating point
237
6672e9e1 238The floating point values byte ordering is defined in the TSDL meta-data.
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239
240Floating point values follow the IEEE 754-2008 standard interchange formats.
241Description of the floating point values include the exponent and mantissa size
242in bits. Some requirements are imposed on the floating point values:
243
244- FLT_RADIX must be 2.
245- mant_dig is the number of digits represented in the mantissa. It is specified
246 by the ISO C99 standard, section 5.2.4, as FLT_MANT_DIG, DBL_MANT_DIG and
247 LDBL_MANT_DIG as defined by <float.h>.
248- exp_dig is the number of digits represented in the exponent. Given that
249 mant_dig is one bit more than its actual size in bits (leading 1 is not
250 needed) and also given that the sign bit always takes one bit, exp_dig can be
251 specified as:
252
253 - sizeof(float) * CHAR_BIT - FLT_MANT_DIG
254 - sizeof(double) * CHAR_BIT - DBL_MANT_DIG
255 - sizeof(long double) * CHAR_BIT - LDBL_MANT_DIG
256
6672e9e1 257TSDL meta-data representation:
5ba9f198 258
80fd2569 259floating_point {
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260 exp_dig = value;
261 mant_dig = value;
262 byte_order = native OR network OR be OR le;
263 align = value;
2152348f 264}
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265
266Example of type inheritance:
267
359894ac 268typealias floating_point {
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269 exp_dig = 8; /* sizeof(float) * CHAR_BIT - FLT_MANT_DIG */
270 mant_dig = 24; /* FLT_MANT_DIG */
271 byte_order = native;
ec4404a7 272 align = 32;
38b8da21 273} := float;
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274
275TODO: define NaN, +inf, -inf behavior.
276
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277Bit-packed, byte-packed or larger alignments can be used for floating
278point values, similarly to integers.
279
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2804.1.8 Enumerations
281
282Enumerations are a mapping between an integer type and a table of strings. The
283numerical representation of the enumeration follows the integer type specified
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284by the meta-data. The enumeration mapping table is detailed in the enumeration
285description within the meta-data. The mapping table maps inclusive value
286ranges (or single values) to strings. Instead of being limited to simple
3bf79539 287"value -> string" mappings, these enumerations map
80fd2569 288"[ start_value ... end_value ] -> string", which map inclusive ranges of
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289values to strings. An enumeration from the C language can be represented in
290this format by having the same start_value and end_value for each element, which
291is in fact a range of size 1. This single-value range is supported without
4767a9e7 292repeating the start and end values with the value = string declaration.
80fd2569 293
a9b83695 294enum name : integer_type {
359894ac 295 somestring = start_value1 ... end_value1,
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296 "other string" = start_value2 ... end_value2,
297 yet_another_string, /* will be assigned to end_value2 + 1 */
298 "some other string" = value,
299 ...
300};
301
302If the values are omitted, the enumeration starts at 0 and increment of 1 for
303each entry:
304
a9b83695 305enum name : unsigned int {
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306 ZERO,
307 ONE,
308 TWO,
309 TEN = 10,
310 ELEVEN,
3bf79539 311};
5ba9f198 312
80fd2569 313Overlapping ranges within a single enumeration are implementation defined.
5ba9f198 314
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315A nameless enumeration can be declared as a field type or as part of a typedef:
316
a9b83695 317enum : integer_type {
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318 ...
319}
320
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321Enumerations omitting the container type ": integer_type" use the "int"
322type (for compatibility with C99). The "int" type must be previously
323declared. E.g.:
324
325typealias integer { size = 32; align = 32; signed = true } := int;
326
327enum {
328 ...
329}
330
1fad7a85 331
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3324.2 Compound types
333
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334Compound are aggregation of type declarations. Compound types include
335structures, variant, arrays, sequences, and strings.
336
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3374.2.1 Structures
338
339Structures are aligned on the largest alignment required by basic types
340contained within the structure. (This follows the ISO/C standard for structures)
341
6672e9e1 342TSDL meta-data representation of a named structure:
5ba9f198 343
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344struct name {
345 field_type field_name;
346 field_type field_name;
347 ...
348};
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349
350Example:
351
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352struct example {
353 integer { /* Nameless type */
354 size = 16;
355 signed = true;
356 align = 16;
357 } first_field_name;
6672e9e1 358 uint64_t second_field_name; /* Named type declared in the meta-data */
3bf79539 359};
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360
361The fields are placed in a sequence next to each other. They each possess a
362field name, which is a unique identifier within the structure.
363
2152348f 364A nameless structure can be declared as a field type or as part of a typedef:
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365
366struct {
367 ...
2152348f 368}
80fd2569 369
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370Alignment for a structure compound type can be forced to a minimum value
371by adding an "align" specifier after the declaration of a structure
372body. This attribute is read as: align(value). The value is specified in
373bits. The structure will be aligned on the maximum value between this
374attribute and the alignment required by the basic types contained within
375the structure. e.g.
376
377struct {
378 ...
379} align(32)
380
77a98c82 3814.2.2 Variants (Discriminated/Tagged Unions)
fcba70d4 382
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383A CTF variant is a selection between different types. A CTF variant must
384always be defined within the scope of a structure or within fields
385contained within a structure (defined recursively). A "tag" enumeration
386field must appear in either the same lexical scope, prior to the variant
387field (in field declaration order), in an uppermost lexical scope (see
6c7226e9 388Section 7.3.1), or in an uppermost dynamic scope (see Section 7.3.2).
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389The type selection is indicated by the mapping from the enumeration
390value to the string used as variant type selector. The field to use as
391tag is specified by the "tag_field", specified between "< >" after the
392"variant" keyword for unnamed variants, and after "variant name" for
393named variants.
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394
395The alignment of the variant is the alignment of the type as selected by the tag
396value for the specific instance of the variant. The alignment of the type
397containing the variant is independent of the variant alignment. The size of the
398variant is the size as selected by the tag value for the specific instance of
399the variant.
400
401A named variant declaration followed by its definition within a structure
402declaration:
403
404variant name {
405 field_type sel1;
406 field_type sel2;
407 field_type sel3;
408 ...
409};
410
411struct {
a9b83695 412 enum : integer_type { sel1, sel2, sel3, ... } tag_field;
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413 ...
414 variant name <tag_field> v;
415}
416
417An unnamed variant definition within a structure is expressed by the following
6672e9e1 418TSDL meta-data:
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419
420struct {
a9b83695 421 enum : integer_type { sel1, sel2, sel3, ... } tag_field;
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422 ...
423 variant <tag_field> {
424 field_type sel1;
425 field_type sel2;
426 field_type sel3;
427 ...
428 } v;
429}
430
431Example of a named variant within a sequence that refers to a single tag field:
432
433variant example {
434 uint32_t a;
435 uint64_t b;
436 short c;
437};
438
439struct {
a9b83695 440 enum : uint2_t { a, b, c } choice;
15850440 441 variant example <choice> v[unsigned int];
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442}
443
444Example of an unnamed variant:
445
446struct {
a9b83695 447 enum : uint2_t { a, b, c, d } choice;
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448 /* Unrelated fields can be added between the variant and its tag */
449 int32_t somevalue;
450 variant <choice> {
451 uint32_t a;
452 uint64_t b;
453 short c;
454 struct {
455 unsigned int field1;
456 uint64_t field2;
457 } d;
458 } s;
459}
460
461Example of an unnamed variant within an array:
462
463struct {
a9b83695 464 enum : uint2_t { a, b, c } choice;
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465 variant <choice> {
466 uint32_t a;
467 uint64_t b;
468 short c;
15850440 469 } v[10];
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470}
471
472Example of a variant type definition within a structure, where the defined type
473is then declared within an array of structures. This variant refers to a tag
474located in an upper lexical scope. This example clearly shows that a variant
475type definition referring to the tag "x" uses the closest preceding field from
476the lexical scope of the type definition.
477
478struct {
a9b83695 479 enum : uint2_t { a, b, c, d } x;
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480
481 typedef variant <x> { /*
482 * "x" refers to the preceding "x" enumeration in the
483 * lexical scope of the type definition.
484 */
485 uint32_t a;
486 uint64_t b;
487 short c;
488 } example_variant;
489
490 struct {
a9b83695 491 enum : int { x, y, z } x; /* This enumeration is not used by "v". */
fcba70d4 492 example_variant v; /*
a9b83695 493 * "v" uses the "enum : uint2_t { a, b, c, d }"
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494 * tag.
495 */
496 } a[10];
497}
498
4994.2.3 Arrays
5ba9f198 500
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501Arrays are fixed-length. Their length is declared in the type
502declaration within the meta-data. They contain an array of "inner type"
503elements, which can refer to any type not containing the type of the
504array being declared (no circular dependency). The length is the number
505of elements in an array.
5ba9f198 506
6672e9e1 507TSDL meta-data representation of a named array:
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508
509typedef elem_type name[length];
5ba9f198 510
2152348f 511A nameless array can be declared as a field type within a structure, e.g.:
5ba9f198 512
2152348f 513 uint8_t field_name[10];
80fd2569 514
ec4404a7 515Arrays are always aligned on their element alignment requirement.
5ba9f198 516
fcba70d4 5174.2.4 Sequences
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518
519Sequences are dynamically-sized arrays. They start with an integer that specify
520the length of the sequence, followed by an array of "inner type" elements.
3bf79539 521The length is the number of elements in the sequence.
5ba9f198 522
6672e9e1 523TSDL meta-data representation for a named sequence:
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524
525typedef elem_type name[length_type];
526
527A nameless sequence can be declared as a field type, e.g.:
528
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529long field_name[int];
530
531The length type follows the integer types specifications, and the sequence
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532elements follow the "array" specifications.
533
fcba70d4 5344.2.5 Strings
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535
536Strings are an array of bytes of variable size and are terminated by a '\0'
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537"NULL" character. Their encoding is described in the TSDL meta-data. In
538absence of encoding attribute information, the default encoding is
539UTF-8.
5ba9f198 540
6672e9e1 541TSDL meta-data representation of a named string type:
80fd2569 542
359894ac 543typealias string {
5ba9f198 544 encoding = UTF8 OR ASCII;
38b8da21 545} := name;
5ba9f198 546
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547A nameless string type can be declared as a field type:
548
549string field_name; /* Use default UTF8 encoding */
5ba9f198 550
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551Strings are always aligned on byte size.
552
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5535. Event Packet Header
554
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555The event packet header consists of two parts: the "event packet header"
556is the same for all streams of a trace. The second part, the "event
557packet context", is described on a per-stream basis. Both are described
558in the TSDL meta-data. The packets are aligned on architecture-page-sized
559addresses.
3bf79539 560
6672e9e1 561Event packet header (all fields are optional, specified by TSDL meta-data):
3bf79539 562
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563- Magic number (CTF magic number: 0xC1FC1FC1) specifies that this is a
564 CTF packet. This magic number is optional, but when present, it should
565 come at the very beginning of the packet.
566- Trace UUID, used to ensure the event packet match the meta-data used.
567 (note: we cannot use a meta-data checksum in every cases instead of a
568 UUID because meta-data can be appended to while tracing is active)
569 This field is optional.
570- Stream ID, used as reference to stream description in meta-data.
571 This field is optional if there is only one stream description in the
572 meta-data, but becomes required if there are more than one stream in
573 the TSDL meta-data description.
3bf79539 574
6672e9e1 575Event packet context (all fields are optional, specified by TSDL meta-data):
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576
577- Event packet content size (in bytes).
578- Event packet size (in bytes, includes padding).
579- Event packet content checksum (optional). Checksum excludes the event packet
580 header.
581- Per-stream event packet sequence count (to deal with UDP packet loss). The
582 number of significant sequence counter bits should also be present, so
b11853af 583 wrap-arounds are dealt with correctly.
6672e9e1 584- Time-stamp at the beginning and time-stamp at the end of the event packet.
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585 Both timestamps are written in the packet header, but sampled respectively
586 while (or before) writing the first event and while (or after) writing the
587 last event in the packet. The inclusive range between these timestamps should
588 include all event timestamps assigned to events contained within the packet.
5ba9f198 589- Events discarded count
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590 - Snapshot of a per-stream free-running counter, counting the number of
591 events discarded that were supposed to be written in the stream prior to
592 the first event in the event packet.
5ba9f198 593 * Note: producer-consumer buffer full condition should fill the current
3bf79539 594 event packet with padding so we know exactly where events have been
5ba9f198 595 discarded.
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596- Lossless compression scheme used for the event packet content. Applied
597 directly to raw data. New types of compression can be added in following
598 versions of the format.
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599 0: no compression scheme
600 1: bzip2
601 2: gzip
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602 3: xz
603- Cypher used for the event packet content. Applied after compression.
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604 0: no encryption
605 1: AES
3bf79539 606- Checksum scheme used for the event packet content. Applied after encryption.
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607 0: no checksum
608 1: md5
609 2: sha1
610 3: crc32
611
6672e9e1 6125.1 Event Packet Header Description
3bf79539 613
fc5425db 614The event packet header layout is indicated by the trace packet.header
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615field. Here is a recommended structure type for the packet header with
616the fields typically expected (although these fields are each optional):
fc5425db 617
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618struct event_packet_header {
619 uint32_t magic;
620 uint8_t trace_uuid[16];
3bf79539 621 uint32_t stream_id;
80fd2569 622};
5ba9f198 623
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624trace {
625 ...
626 packet.header := struct event_packet_header;
627};
628
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629If the magic number is not present, tools such as "file" will have no
630mean to discover the file type.
631
632If the trace_uuid is not present, no validation that the meta-data
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633actually corresponds to the stream is performed.
634
635If the stream_id packet header field is missing, the trace can only
636contain a single stream. Its "id" field can be left out, and its events
637don't need to declare a "stream_id" field.
638
639
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6405.2 Event Packet Context Description
641
642Event packet context example. These are declared within the stream declaration
6672e9e1 643in the meta-data. All these fields are optional. If the packet size field is
6a7c61df 644missing, the whole stream only contains a single packet. If the content
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645size field is missing, the packet is filled (no padding). The content
646and packet sizes include all headers.
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647
648An example event packet context type:
649
80fd2569 650struct event_packet_context {
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651 uint64_t timestamp_begin;
652 uint64_t timestamp_end;
653 uint32_t checksum;
654 uint32_t stream_packet_count;
655 uint32_t events_discarded;
656 uint32_t cpu_id;
657 uint32_t/uint16_t content_size;
658 uint32_t/uint16_t packet_size;
659 uint8_t stream_packet_count_bits; /* Significant counter bits */
660 uint8_t compression_scheme;
661 uint8_t encryption_scheme;
3b0f8e4d 662 uint8_t checksum_scheme;
3bf79539 663};
5ba9f198 664
fcba70d4 665
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6666. Event Structure
667
668The overall structure of an event is:
669
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6701 - Stream Packet Context (as specified by the stream meta-data)
671 2 - Event Header (as specified by the stream meta-data)
672 3 - Stream Event Context (as specified by the stream meta-data)
673 4 - Event Context (as specified by the event meta-data)
674 5 - Event Payload (as specified by the event meta-data)
5ba9f198 675
fdf2bb05 676This structure defines an implicit dynamic scoping, where variants
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677located in inner structures (those with a higher number in the listing
678above) can refer to the fields of outer structures (with lower number in
6c7226e9 679the listing above). See Section 7.3 TSDL Scopes for more detail.
5ba9f198 680
fdf2bb05 6816.1 Event Header
fcba70d4 682
6672e9e1 683Event headers can be described within the meta-data. We hereby propose, as an
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684example, two types of events headers. Type 1 accommodates streams with less than
68531 event IDs. Type 2 accommodates streams with 31 or more event IDs.
5ba9f198 686
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687One major factor can vary between streams: the number of event IDs assigned to
688a stream. Luckily, this information tends to stay relatively constant (modulo
5ba9f198 689event registration while trace is being recorded), so we can specify different
3bf79539 690representations for streams containing few event IDs and streams containing
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691many event IDs, so we end up representing the event ID and time-stamp as
692densely as possible in each case.
5ba9f198 693
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694The header is extended in the rare occasions where the information cannot be
695represented in the ranges available in the standard event header. They are also
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696used in the rare occasions where the data required for a field could not be
697collected: the flag corresponding to the missing field within the missing_fields
698array is then set to 1.
5ba9f198 699
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700Types uintX_t represent an X-bit unsigned integer, as declared with
701either:
5ba9f198 702
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703 typealias integer { size = X; align = X; signed = false } := uintX_t;
704
705 or
706
707 typealias integer { size = X; align = 1; signed = false } := uintX_t;
5ba9f198 708
fdf2bb05 7096.1.1 Type 1 - Few event IDs
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710
711 - Aligned on 32-bit (or 8-bit if byte-packed, depending on the architecture
712 preference).
5ba9f198 713 - Native architecture byte ordering.
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714 - For "compact" selection
715 - Fixed size: 32 bits.
716 - For "extended" selection
717 - Size depends on the architecture and variant alignment.
5ba9f198 718
80fd2569 719struct event_header_1 {
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720 /*
721 * id: range: 0 - 30.
722 * id 31 is reserved to indicate an extended header.
723 */
a9b83695 724 enum : uint5_t { compact = 0 ... 30, extended = 31 } id;
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725 variant <id> {
726 struct {
727 uint27_t timestamp;
728 } compact;
729 struct {
730 uint32_t id; /* 32-bit event IDs */
731 uint64_t timestamp; /* 64-bit timestamps */
732 } extended;
733 } v;
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734};
735
5ba9f198 736
fdf2bb05 7376.1.2 Type 2 - Many event IDs
5ba9f198 738
fcba70d4 739 - Aligned on 16-bit (or 8-bit if byte-packed, depending on the architecture
5ba9f198 740 preference).
5ba9f198 741 - Native architecture byte ordering.
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742 - For "compact" selection
743 - Size depends on the architecture and variant alignment.
744 - For "extended" selection
745 - Size depends on the architecture and variant alignment.
5ba9f198 746
80fd2569 747struct event_header_2 {
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748 /*
749 * id: range: 0 - 65534.
750 * id 65535 is reserved to indicate an extended header.
751 */
a9b83695 752 enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;
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753 variant <id> {
754 struct {
755 uint32_t timestamp;
756 } compact;
757 struct {
758 uint32_t id; /* 32-bit event IDs */
759 uint64_t timestamp; /* 64-bit timestamps */
760 } extended;
761 } v;
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762};
763
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764
7656.2 Event Context
766
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767The event context contains information relative to the current event.
768The choice and meaning of this information is specified by the TSDL
769stream and event meta-data descriptions. The stream context is applied
770to all events within the stream. The stream context structure follows
771the event header. The event context is applied to specific events. Its
772structure follows the stream context structure.
5ba9f198 773
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774An example of stream-level event context is to save the event payload size with
775each event, or to save the current PID with each event. These are declared
6672e9e1 776within the stream declaration within the meta-data:
5ba9f198 777
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778 stream {
779 ...
6672e9e1 780 event.context := struct {
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781 uint pid;
782 uint16_t payload_size;
6672e9e1 783 };
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784 };
785
786An example of event-specific event context is to declare a bitmap of missing
787fields, only appended after the stream event context if the extended event
788header is selected. NR_FIELDS is the number of fields within the event (a
789numeric value).
5ba9f198 790
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791 event {
792 context = struct {
793 variant <id> {
794 struct { } compact;
795 struct {
796 uint1_t missing_fields[NR_FIELDS]; /* missing event fields bitmap */
797 } extended;
798 } v;
799 };
800 ...
801 }
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802
8036.3 Event Payload
804
805An event payload contains fields specific to a given event type. The fields
6672e9e1 806belonging to an event type are described in the event-specific meta-data
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807within a structure type.
808
8096.3.1 Padding
810
811No padding at the end of the event payload. This differs from the ISO/C standard
812for structures, but follows the CTF standard for structures. In a trace, even
813though it makes sense to align the beginning of a structure, it really makes no
814sense to add padding at the end of the structure, because structures are usually
815not followed by a structure of the same type.
816
817This trick can be done by adding a zero-length "end" field at the end of the C
818structures, and by using the offset of this field rather than using sizeof()
3bf79539 819when calculating the size of a structure (see Appendix "A. Helper macros").
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820
8216.3.2 Alignment
822
823The event payload is aligned on the largest alignment required by types
824contained within the payload. (This follows the ISO/C standard for structures)
825
826
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8277. Trace Stream Description Language (TSDL)
828
829The Trace Stream Description Language (TSDL) allows expression of the
830binary trace streams layout in a C99-like Domain Specific Language
831(DSL).
832
833
6672e9e1 8347.1 Meta-data
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835
836The trace stream layout description is located in the trace meta-data.
837The meta-data is itself located in a stream identified by its name:
838"metadata".
5ba9f198 839
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840The meta-data description can be expressed in two different formats:
841text-only and packet-based. The text-only description facilitates
842generation of meta-data and provides a convenient way to enter the
843meta-data information by hand. The packet-based meta-data provides the
844CTF stream packet facilities (checksumming, compression, encryption,
845network-readiness) for meta-data stream generated and transported by a
846tracer.
847
848The text-only meta-data file is a plain text TSDL description.
849
850The packet-based meta-data is made of "meta-data packets", which each
851start with a meta-data packet header. The packet-based meta-data
852description is detected by reading the magic number "0x75D11D57" at the
853beginning of the file. This magic number is also used to detect the
854endianness of the architecture by trying to read the CTF magic number
855and its counterpart in reversed endianness. The events within the
856meta-data stream have no event header nor event context. Each event only
857contains a "string" payload. Each meta-data packet start with a special
858packet header, specific to the meta-data stream, which contains,
859exactly:
860
861struct metadata_packet_header {
2daeaa3a 862 uint32_t magic; /* 0x75D11D57 */
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863 uint8_t trace_uuid[16]; /* Unique Universal Identifier */
864 uint32_t checksum; /* 0 if unused */
865 uint32_t content_size; /* in bits */
866 uint32_t packet_size; /* in bits */
867 uint8_t compression_scheme; /* 0 if unused */
868 uint8_t encryption_scheme; /* 0 if unused */
869 uint8_t checksum_scheme; /* 0 if unused */
870};
871
872The packet-based meta-data can be converted to a text-only meta-data by
873concatenating all the strings in contains.
4fafe1ad 874
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875In the textual representation of the meta-data, the text contained
876within "/*" and "*/", as well as within "//" and end of line, are
877treated as comments. Boolean values can be represented as true, TRUE,
878or 1 for true, and false, FALSE, or 0 for false. Within the string-based
879meta-data description, the trace UUID is represented as a string of
880hexadecimal digits and dashes "-". In the event packet header, the trace
881UUID is represented as an array of bytes.
fcba70d4 882
fdf2bb05 883
6c7226e9 8847.2 Declaration vs Definition
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885
886A declaration associates a layout to a type, without specifying where
887this type is located in the event structure hierarchy (see Section 6).
888This therefore includes typedef, typealias, as well as all type
889specifiers. In certain circumstances (typedef, structure field and
890variant field), a declaration is followed by a declarator, which specify
891the newly defined type name (for typedef), or the field name (for
892declarations located within structure and variants). Array and sequence,
893declared with square brackets ("[" "]"), are part of the declarator,
a9b83695 894similarly to C99. The enumeration base type is specified by
6c7226e9 895": enum_base", which is part of the type specifier. The variant tag
a9b83695 896name, specified between "<" ">", is also part of the type specifier.
fdf2bb05
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897
898A definition associates a type to a location in the event structure
b9606a77
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899hierarchy (see Section 6). This association is denoted by ":=", as shown
900in Section 7.3.
fdf2bb05
MD
901
902
6c7226e9 9037.3 TSDL Scopes
fdf2bb05 904
6c7226e9
MD
905TSDL uses two different types of scoping: a lexical scope is used for
906declarations and type definitions, and a dynamic scope is used for
907variants references to tag fields.
fdf2bb05 908
6c7226e9 9097.3.1 Lexical Scope
fdf2bb05 910
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911Each of "trace", "stream", "event", "struct" and "variant" have their own
912nestable declaration scope, within which types can be declared using "typedef"
fdf2bb05 913and "typealias". A root declaration scope also contains all declarations
7d9d7e92 914located outside of any of the aforementioned declarations. An inner
fdf2bb05 915declaration scope can refer to type declared within its container
7d9d7e92
MD
916lexical scope prior to the inner declaration scope. Redefinition of a
917typedef or typealias is not valid, although hiding an upper scope
fdf2bb05
MD
918typedef or typealias is allowed within a sub-scope.
919
6c7226e9 9207.3.2 Dynamic Scope
fdf2bb05 921
7d9d7e92
MD
922A dynamic scope consists in the lexical scope augmented with the
923implicit event structure definition hierarchy presented at Section 6.
924The dynamic scope is only used for variant tag definitions. It is used
925at definition time to look up the location of the tag field associated
926with a variant.
927
928Therefore, variants in lower levels in the dynamic scope (e.g. event
929context) can refer to a tag field located in upper levels (e.g. in the
930event header) by specifying, in this case, the associated tag with
931<header.field_name>. This allows, for instance, the event context to
932define a variant referring to the "id" field of the event header as
933selector.
fdf2bb05
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934
935The target dynamic scope must be specified explicitly when referring to
936a field outside of the local static scope. The dynamic scope prefixes
937are thus:
938
e0d9e2c7 939 - Trace Packet Header: <trace.packet.header. >,
7d9d7e92
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940 - Stream Packet Context: <stream.packet.context. >,
941 - Event Header: <stream.event.header. >,
942 - Stream Event Context: <stream.event.context. >,
943 - Event Context: <event.context. >,
944 - Event Payload: <event.fields. >.
fdf2bb05
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945
946Multiple declarations of the same field name within a single scope is
947not valid. It is however valid to re-use the same field name in
948different scopes. There is no possible conflict, because the dynamic
949scope must be specified when a variant refers to a tag field located in
950a different dynamic scope.
951
457d8b0a
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952The information available in the dynamic scopes can be thought of as the
953current tracing context. At trace production, information about the
954current context is saved into the specified scope field levels. At trace
955consumption, for each event, the current trace context is therefore
956readable by accessing the upper dynamic scopes.
957
fdf2bb05 958
6c7226e9 9597.4 TSDL Examples
d285084f 960
6672e9e1 961The grammar representing the TSDL meta-data is presented in Appendix C.
7df6b93a 962TSDL Grammar. This section presents a rather lighter reading that
6672e9e1 963consists in examples of TSDL meta-data, with template values.
969f30c0 964
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MD
965The stream "id" can be left out if there is only one stream in the
966trace. The event "id" field can be left out if there is only one event
967in a stream.
968
5ba9f198 969trace {
fdf2bb05 970 major = value; /* Trace format version */
5ba9f198 971 minor = value;
fdf2bb05 972 uuid = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"; /* Trace UUID */
58997e9e 973 byte_order = be OR le; /* Endianness (required) */
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974 packet.header := struct {
975 uint32_t magic;
976 uint8_t trace_uuid[16];
977 uint32_t stream_id;
978 };
3bf79539 979};
5ba9f198 980
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MD
981stream {
982 id = stream_id;
fdf2bb05 983 /* Type 1 - Few event IDs; Type 2 - Many event IDs. See section 6.1. */
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MD
984 event.header := event_header_1 OR event_header_2;
985 event.context := struct {
77a98c82 986 ...
3bf79539 987 };
4fa992a5 988 packet.context := struct {
77a98c82 989 ...
3bf79539
MD
990 };
991};
5ba9f198
MD
992
993event {
3d13ef1a 994 name = event_name;
3bf79539 995 id = value; /* Numeric identifier within the stream */
67f02e24 996 stream_id = stream_id;
4fa992a5 997 context := struct {
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MD
998 ...
999 };
4fa992a5 1000 fields := struct {
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MD
1001 ...
1002 };
3bf79539 1003};
5ba9f198
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1004
1005/* More detail on types in section 4. Types */
1006
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1007/*
1008 * Named types:
1009 *
4fa992a5 1010 * Type declarations behave similarly to the C standard.
3d13ef1a
MD
1011 */
1012
80af8ac6 1013typedef aliased_type_specifiers new_type_declarators;
2152348f 1014
3d13ef1a 1015/* e.g.: typedef struct example new_type_name[10]; */
80fd2569 1016
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1017/*
1018 * typealias
1019 *
1020 * The "typealias" declaration can be used to give a name (including
80af8ac6
MD
1021 * pointer declarator specifier) to a type. It should also be used to
1022 * map basic C types (float, int, unsigned long, ...) to a CTF type.
1023 * Typealias is a superset of "typedef": it also allows assignment of a
38b8da21 1024 * simple variable identifier to a type.
4fa992a5
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1025 */
1026
1027typealias type_class {
80fd2569 1028 ...
38b8da21 1029} := type_specifiers type_declarator;
2152348f 1030
3d13ef1a
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1031/*
1032 * e.g.:
4fa992a5 1033 * typealias integer {
3d13ef1a
MD
1034 * size = 32;
1035 * align = 32;
1036 * signed = false;
38b8da21 1037 * } := struct page *;
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1038 *
1039 * typealias integer {
1040 * size = 32;
1041 * align = 32;
1042 * signed = true;
38b8da21 1043 * } := int;
3d13ef1a 1044 */
80fd2569
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1045
1046struct name {
3bf79539
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1047 ...
1048};
5ba9f198 1049
fcba70d4
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1050variant name {
1051 ...
1052};
1053
a9b83695 1054enum name : integer_type {
3bf79539
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1055 ...
1056};
1057
2152348f 1058
4fa992a5
MD
1059/*
1060 * Unnamed types, contained within compound type fields, typedef or typealias.
1061 */
2152348f 1062
80fd2569
MD
1063struct {
1064 ...
2152348f 1065}
5ba9f198 1066
ec4404a7
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1067struct {
1068 ...
1069} align(value)
1070
fcba70d4
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1071variant {
1072 ...
1073}
1074
a9b83695 1075enum : integer_type {
80fd2569 1076 ...
2152348f
MD
1077}
1078
1079typedef type new_type[length];
3bf79539 1080
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MD
1081struct {
1082 type field_name[length];
1083}
1084
1085typedef type new_type[length_type];
1086
1087struct {
1088 type field_name[length_type];
1089}
1090
1091integer {
80fd2569 1092 ...
2152348f 1093}
3bf79539 1094
2152348f 1095floating_point {
80fd2569 1096 ...
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MD
1097}
1098
1099struct {
1100 integer_type field_name:size; /* GNU/C bitfield */
1101}
1102
1103struct {
1104 string field_name;
1105}
3bf79539 1106
fcba70d4 1107
3bf79539 1108A. Helper macros
5ba9f198
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1109
1110The two following macros keep track of the size of a GNU/C structure without
1111padding at the end by placing HEADER_END as the last field. A one byte end field
1112is used for C90 compatibility (C99 flexible arrays could be used here). Note
1113that this does not affect the effective structure size, which should always be
1114calculated with the header_sizeof() helper.
1115
1116#define HEADER_END char end_field
1117#define header_sizeof(type) offsetof(typeof(type), end_field)
3bf79539
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1118
1119
1120B. Stream Header Rationale
1121
1122An event stream is divided in contiguous event packets of variable size. These
1123subdivisions allow the trace analyzer to perform a fast binary search by time
1124within the stream (typically requiring to index only the event packet headers)
1125without reading the whole stream. These subdivisions have a variable size to
1126eliminate the need to transfer the event packet padding when partially filled
1127event packets must be sent when streaming a trace for live viewing/analysis.
1128An event packet can contain a certain amount of padding at the end. Dividing
1129streams into event packets is also useful for network streaming over UDP and
1130flight recorder mode tracing (a whole event packet can be swapped out of the
1131buffer atomically for reading).
1132
1133The stream header is repeated at the beginning of each event packet to allow
1134flexibility in terms of:
1135
1136 - streaming support,
1137 - allowing arbitrary buffers to be discarded without making the trace
1138 unreadable,
1139 - allow UDP packet loss handling by either dealing with missing event packet
1140 or asking for re-transmission.
1141 - transparently support flight recorder mode,
1142 - transparently support crash dump.
1143
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1144
1145C. TSDL Grammar
fcba70d4 1146
4fa992a5 1147/*
6c7226e9 1148 * Common Trace Format (CTF) Trace Stream Description Language (TSDL) Grammar.
4fa992a5
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1149 *
1150 * Inspired from the C99 grammar:
1151 * http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf (Annex A)
6c7226e9
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1152 * and c++1x grammar (draft)
1153 * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3291.pdf (Annex A)
4fa992a5
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1154 *
1155 * Specialized for CTF needs by including only constant and declarations from
1156 * C99 (excluding function declarations), and by adding support for variants,
6c7226e9
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1157 * sequences and CTF-specific specifiers. Enumeration container types
1158 * semantic is inspired from c++1x enum-base.
4fa992a5
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1159 */
1160
11611) Lexical grammar
1162
11631.1) Lexical elements
1164
1165token:
1166 keyword
1167 identifier
1168 constant
1169 string-literal
1170 punctuator
1171
11721.2) Keywords
1173
1174keyword: is one of
1175
ec4404a7 1176align
4fa992a5
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1177const
1178char
1179double
1180enum
1181event
1182floating_point
1183float
1184integer
1185int
1186long
1187short
1188signed
1189stream
1190string
1191struct
1192trace
3e1e1a78 1193typealias
4fa992a5
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1194typedef
1195unsigned
1196variant
1197void
1198_Bool
1199_Complex
1200_Imaginary
1201
1202
12031.3) Identifiers
1204
1205identifier:
1206 identifier-nondigit
1207 identifier identifier-nondigit
1208 identifier digit
1209
1210identifier-nondigit:
1211 nondigit
1212 universal-character-name
1213 any other implementation-defined characters
1214
1215nondigit:
1216 _
1217 [a-zA-Z] /* regular expression */
1218
1219digit:
1220 [0-9] /* regular expression */
1221
12221.4) Universal character names
1223
1224universal-character-name:
1225 \u hex-quad
1226 \U hex-quad hex-quad
1227
1228hex-quad:
1229 hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit
1230
12311.5) Constants
1232
1233constant:
1234 integer-constant
1235 enumeration-constant
1236 character-constant
1237
1238integer-constant:
1239 decimal-constant integer-suffix-opt
1240 octal-constant integer-suffix-opt
1241 hexadecimal-constant integer-suffix-opt
1242
1243decimal-constant:
1244 nonzero-digit
1245 decimal-constant digit
1246
1247octal-constant:
1248 0
1249 octal-constant octal-digit
1250
1251hexadecimal-constant:
1252 hexadecimal-prefix hexadecimal-digit
1253 hexadecimal-constant hexadecimal-digit
1254
1255hexadecimal-prefix:
1256 0x
1257 0X
1258
1259nonzero-digit:
1260 [1-9]
1261
1262integer-suffix:
1263 unsigned-suffix long-suffix-opt
1264 unsigned-suffix long-long-suffix
1265 long-suffix unsigned-suffix-opt
1266 long-long-suffix unsigned-suffix-opt
1267
1268unsigned-suffix:
1269 u
1270 U
1271
1272long-suffix:
1273 l
1274 L
1275
1276long-long-suffix:
1277 ll
1278 LL
1279
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1280enumeration-constant:
1281 identifier
1282 string-literal
1283
1284character-constant:
1285 ' c-char-sequence '
1286 L' c-char-sequence '
1287
1288c-char-sequence:
1289 c-char
1290 c-char-sequence c-char
1291
1292c-char:
1293 any member of source charset except single-quote ('), backslash
1294 (\), or new-line character.
1295 escape-sequence
1296
1297escape-sequence:
1298 simple-escape-sequence
1299 octal-escape-sequence
1300 hexadecimal-escape-sequence
1301 universal-character-name
1302
1303simple-escape-sequence: one of
1304 \' \" \? \\ \a \b \f \n \r \t \v
1305
1306octal-escape-sequence:
1307 \ octal-digit
1308 \ octal-digit octal-digit
1309 \ octal-digit octal-digit octal-digit
1310
1311hexadecimal-escape-sequence:
1312 \x hexadecimal-digit
1313 hexadecimal-escape-sequence hexadecimal-digit
1314
13151.6) String literals
1316
1317string-literal:
1318 " s-char-sequence-opt "
1319 L" s-char-sequence-opt "
1320
1321s-char-sequence:
1322 s-char
1323 s-char-sequence s-char
1324
1325s-char:
1326 any member of source charset except double-quote ("), backslash
1327 (\), or new-line character.
1328 escape-sequence
1329
13301.7) Punctuators
1331
1332punctuator: one of
1333 [ ] ( ) { } . -> * + - < > : ; ... = ,
1334
1335
13362) Phrase structure grammar
1337
1338primary-expression:
1339 identifier
1340 constant
1341 string-literal
1342 ( unary-expression )
1343
1344postfix-expression:
1345 primary-expression
1346 postfix-expression [ unary-expression ]
1347 postfix-expression . identifier
1348 postfix-expressoin -> identifier
1349
1350unary-expression:
1351 postfix-expression
1352 unary-operator postfix-expression
1353
1354unary-operator: one of
1355 + -
1356
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1357assignment-operator:
1358 =
1359
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1360type-assignment-operator:
1361 :=
1362
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1363constant-expression:
1364 unary-expression
1365
1366constant-expression-range:
1367 constant-expression ... constant-expression
1368
13692.2) Declarations:
1370
1371declaration:
689e04b4 1372 declaration-specifiers declarator-list-opt ;
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1373 ctf-specifier ;
1374
1375declaration-specifiers:
689e04b4 1376 storage-class-specifier declaration-specifiers-opt
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1377 type-specifier declaration-specifiers-opt
1378 type-qualifier declaration-specifiers-opt
1379
1380declarator-list:
1381 declarator
1382 declarator-list , declarator
1383
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1384abstract-declarator-list:
1385 abstract-declarator
1386 abstract-declarator-list , abstract-declarator
1387
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1388storage-class-specifier:
1389 typedef
1390
1391type-specifier:
1392 void
1393 char
1394 short
1395 int
1396 long
1397 float
1398 double
1399 signed
1400 unsigned
1401 _Bool
1402 _Complex
cfdd51ec 1403 _Imaginary
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1404 struct-specifier
1405 variant-specifier
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1406 enum-specifier
1407 typedef-name
1408 ctf-type-specifier
1409
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1410align-attribute:
1411 align ( constant-expression )
1412
4fa992a5 1413struct-specifier:
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1414 struct identifier-opt { struct-or-variant-declaration-list-opt } align-attribute-opt
1415 struct identifier align-attribute-opt
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1416
1417struct-or-variant-declaration-list:
1418 struct-or-variant-declaration
1419 struct-or-variant-declaration-list struct-or-variant-declaration
1420
1421struct-or-variant-declaration:
1422 specifier-qualifier-list struct-or-variant-declarator-list ;
550aca33 1423 declaration-specifiers storage-class-specifier declaration-specifiers declarator-list ;
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1424 typealias declaration-specifiers abstract-declarator-list := declaration-specifiers abstract-declarator-list ;
1425 typealias declaration-specifiers abstract-declarator-list := declarator-list ;
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1426
1427specifier-qualifier-list:
1428 type-specifier specifier-qualifier-list-opt
1429 type-qualifier specifier-qualifier-list-opt
1430
1431struct-or-variant-declarator-list:
1432 struct-or-variant-declarator
1433 struct-or-variant-declarator-list , struct-or-variant-declarator
1434
1435struct-or-variant-declarator:
1436 declarator
1437 declarator-opt : constant-expression
1438
1439variant-specifier:
1440 variant identifier-opt variant-tag-opt { struct-or-variant-declaration-list }
1441 variant identifier variant-tag
1442
1443variant-tag:
1444 < identifier >
1445
1446enum-specifier:
1447 enum identifier-opt { enumerator-list }
1448 enum identifier-opt { enumerator-list , }
1449 enum identifier
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1450 enum identifier-opt : declaration-specifiers { enumerator-list }
1451 enum identifier-opt : declaration-specifiers { enumerator-list , }
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1452
1453enumerator-list:
1454 enumerator
1455 enumerator-list , enumerator
1456
1457enumerator:
1458 enumeration-constant
1459 enumeration-constant = constant-expression
1460 enumeration-constant = constant-expression-range
1461
1462type-qualifier:
1463 const
1464
1465declarator:
1466 pointer-opt direct-declarator
1467
1468direct-declarator:
1469 identifier
1470 ( declarator )
1471 direct-declarator [ type-specifier ]
1472 direct-declarator [ constant-expression ]
1473
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1474abstract-declarator:
1475 pointer-opt direct-abstract-declarator
1476
1477direct-abstract-declarator:
1478 identifier-opt
1479 ( abstract-declarator )
1480 direct-abstract-declarator [ type-specifier ]
1481 direct-abstract-declarator [ constant-expression ]
1482 direct-abstract-declarator [ ]
1483
4fa992a5 1484pointer:
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1485 * type-qualifier-list-opt
1486 * type-qualifier-list-opt pointer
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1487
1488type-qualifier-list:
1489 type-qualifier
1490 type-qualifier-list type-qualifier
1491
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1492typedef-name:
1493 identifier
1494
14952.3) CTF-specific declarations
1496
1497ctf-specifier:
1498 event { ctf-assignment-expression-list-opt }
1499 stream { ctf-assignment-expression-list-opt }
1500 trace { ctf-assignment-expression-list-opt }
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1501 typealias declaration-specifiers abstract-declarator-list := declaration-specifiers abstract-declarator-list ;
1502 typealias declaration-specifiers abstract-declarator-list := declarator-list ;
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1503
1504ctf-type-specifier:
1505 floating_point { ctf-assignment-expression-list-opt }
1506 integer { ctf-assignment-expression-list-opt }
1507 string { ctf-assignment-expression-list-opt }
1508
1509ctf-assignment-expression-list:
1510 ctf-assignment-expression
1511 ctf-assignment-expression-list ; ctf-assignment-expression
1512
1513ctf-assignment-expression:
1514 unary-expression assignment-operator unary-expression
1515 unary-expression type-assignment-operator type-specifier
550aca33 1516 declaration-specifiers storage-class-specifier declaration-specifiers declarator-list
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1517 typealias declaration-specifiers abstract-declarator-list := declaration-specifiers abstract-declarator-list
1518 typealias declaration-specifiers abstract-declarator-list := declarator-list
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