Cleanup: update alignment of TOC

[ctf.git] / common-trace-format-specification.txt

diff --git a/common-trace-format-specification.txt b/common-trace-format-specification.txt
index d3b354a5a63647b1f5794f9c35ffbe0cee683def..4af2244ab37adfa5a513cff029811cbdcc48bcea 100644 (file)
--- a/common-trace-format-specification.txt
+++ b/common-trace-format-specification.txt
@@ -1,4 +1,4 @@
-Common Trace Format (CTF) Specification (v1.8.1)
+Common Trace Format (CTF) Specification (v1.8.2)

 
 Mathieu Desnoyers, EfficiOS Inc.
 
 
 Mathieu Desnoyers, EfficiOS Inc.
 


@@ -41,12 +41,12 @@ Table of Contents
        4.1.6 GNU/C bitfields
        4.1.7 Floating point
        4.1.8 Enumerations
        4.1.6 GNU/C bitfields
        4.1.7 Floating point
        4.1.8 Enumerations

-4.2 Compound types
-    4.2.1 Structures
-    4.2.2 Variants (Discriminated/Tagged Unions)
-    4.2.3 Arrays
-    4.2.4 Sequences
-    4.2.5 Strings
+   4.2 Compound types
+       4.2.1 Structures
+       4.2.2 Variants (Discriminated/Tagged Unions)
+       4.2.3 Arrays
+       4.2.4 Sequences
+       4.2.5 Strings

 5. Event Packet Header
    5.1 Event Packet Header Description
    5.2 Event Packet Context Description
 5. Event Packet Header
    5.1 Event Packet Header Description
    5.2 Event Packet Context Description


@@ -54,7 +54,7 @@ Table of Contents
    6.1 Event Header
        6.1.1 Type 1 - Few event IDs
        6.1.2 Type 2 - Many event IDs
    6.1 Event Header
        6.1.1 Type 1 - Few event IDs
        6.1.2 Type 2 - Many event IDs

-   6.2 Event Context
+   6.2 Stream Event Context and Event Context

    6.3 Event Payload
        6.3.1 Padding
        6.3.2 Alignment
    6.3 Event Payload
        6.3.1 Padding
        6.3.2 Alignment


@@ -165,22 +165,35 @@ by default. It is however recommended to always specify the alignment
 explicitly. Alignment values must be power of two. Compound types are
 aligned as specified in their individual specification.
 
 explicitly. Alignment values must be power of two. Compound types are
 aligned as specified in their individual specification.
 

+The base offset used for field alignment is the start of the packet
+containing the field. For instance, a field aligned on 32-bit needs to
+be at an offset multiple of 32-bit from the start of the packet that
+contains it.
+

 TSDL meta-data attribute representation of a specific alignment:
 
   align = value;                                /* value in bits */
 
 4.1.3 Byte order
 
 TSDL meta-data attribute representation of a specific alignment:
 
   align = value;                                /* value in bits */
 
 4.1.3 Byte order
 

-By default, the native endianness of the source architecture is used.
-Byte order can be overridden for a basic type by specifying a "byte_order"
-attribute. Typical use-case is to specify the network byte order (big endian:
-"be") to save data captured from the network into the trace without conversion.
-If not specified, the byte order is native.
+By default, byte order of a basic type is the byte order described in
+the trace description.  It can be overridden by specifying a
+"byte_order" attribute for a basic type.  Typical use-case is to specify
+the network byte order (big endian: "be") to save data captured from the
+network into the trace without conversion.

 
 TSDL meta-data representation:
 
   byte_order = native OR network OR be OR le;  /* network and be are aliases */
 
 
 TSDL meta-data representation:
 
   byte_order = native OR network OR be OR le;  /* network and be are aliases */
 

+The "native" keyword selects the byte order described in the trace
+description. The "network" byte order is an alias for big endian.
+
+Even though the trace description section is not per se a type, for sake
+of clarity, it should be noted that "native" and "network" byte orders
+are only allowed within type declaration. The byte_order specified in
+the trace description section only accepts "be" or "le" values.
+

 4.1.4 Size
 
 Type size, in bits, for integers and floats is that returned by "sizeof()" in C
 4.1.4 Size
 
 Type size, in bits, for integers and floats is that returned by "sizeof()" in C


@@ -235,7 +248,7 @@ TSDL meta-data representation:
     size = value;                               /* value in bits, no default */
     align = value;                              /* value in bits */
     /* based used for pretty-printing output, default: decimal. */
     size = value;                               /* value in bits, no default */
     align = value;                              /* value in bits */
     /* based used for pretty-printing output, default: decimal. */

-    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
+    base = decimal OR dec OR d OR i OR u OR 10 OR hexadecimal OR hex OR x OR X OR p OR 16

            OR octal OR oct OR o OR 8 OR binary OR b OR 2;
     /* character encoding, default: none */
     encoding = none or UTF8 or ASCII;
            OR octal OR oct OR o OR 8 OR binary OR b OR 2;
     /* character encoding, default: none */
     encoding = none or UTF8 or ASCII;


@@ -380,7 +393,7 @@ Enumerations omitting the container type ": integer_type" use the "int"
 type (for compatibility with C99). The "int" type must be previously
 declared. E.g.:
 
 type (for compatibility with C99). The "int" type must be previously
 declared. E.g.:
 

-typealias integer { size = 32; align = 32; signed = true } := int;
+typealias integer { size = 32; align = 32; signed = true; } := int;

 
 enum {
   ...
 
 enum {
   ...


@@ -454,11 +467,28 @@ type selector. The field to use as tag is specified by the "tag_field",
 specified between "< >" after the "variant" keyword for unnamed
 variants, and after "variant name" for named variants.
 
 specified between "< >" after the "variant" keyword for unnamed
 variants, and after "variant name" for named variants.
 

-The alignment of the variant is the alignment of the type as selected by the tag
-value for the specific instance of the variant. The alignment of the type
-containing the variant is independent of the variant alignment.  The size of the
-variant is the size as selected by the tag value for the specific instance of
-the variant.
+The alignment of the variant is the alignment of the type as selected by
+the tag value for the specific instance of the variant.  The size of the
+variant is the size as selected by the tag value for the specific
+instance of the variant.
+
+The alignment of the type containing the variant is independent of the
+variant alignment.  For instance, if a structure contains two fields, a
+32-bit integer, aligned on 32 bits, and a variant, which contains two
+choices: either a 32-bit field, aligned on 32 bits, or a 64-bit field,
+aligned on 64 bits, the alignment of the outmost structure will be
+32-bit (the alignment of its largest field, disregarding the alignment
+of the variant). The alignment of the variant will depend on the
+selector: if the variant's 32-bit field is selected, its alignment will
+be 32-bit, or 64-bit otherwise. It is important to note that variants
+are specifically tailored for compactness in a stream. Therefore, the
+relative offsets of compound type fields can vary depending on
+the offset at which the compound type starts if it contains a variant
+that itself contains a type with alignment larger than the largest field
+contained within the compound type. This is caused by the fact that the
+compound type may contain the enumeration that select the variant's
+choice, and therefore the alignment to be applied to the compound type
+cannot be determined before encountering the enumeration.

 
 Each variant type selector possess a field name, which is a unique
 identifier within the variant. The identifier is not allowed to use any
 
 Each variant type selector possess a field name, which is a unique
 identifier within the variant. The identifier is not allowed to use any


@@ -587,7 +617,7 @@ Arrays are always aligned on their element alignment requirement.
 
 4.2.4 Sequences
 
 
 4.2.4 Sequences
 

-Sequences are dynamically-sized arrays. They refer to a a "length"
+Sequences are dynamically-sized arrays. They refer to a "length"

 unsigned integer field, which must appear in either the same static scope,
 prior to the sequence field (in field declaration order), in an upper
 static scope, or in an upper dynamic scope (see Section 7.3.2). This
 unsigned integer field, which must appear in either the same static scope,
 prior to the sequence field (in field declaration order), in an upper
 static scope, or in an upper dynamic scope (see Section 7.3.2). This


@@ -657,8 +687,7 @@ Strings are always aligned on byte size.
 The event packet header consists of two parts: the "event packet header"
 is the same for all streams of a trace. The second part, the "event
 packet context", is described on a per-stream basis. Both are described
 The event packet header consists of two parts: the "event packet header"
 is the same for all streams of a trace. The second part, the "event
 packet context", is described on a per-stream basis. Both are described

-in the TSDL meta-data. The packets are aligned on architecture-page-sized
-addresses.
+in the TSDL meta-data.

 
 Event packet header (all fields are optional, specified by TSDL meta-data):
 
 
 Event packet header (all fields are optional, specified by TSDL meta-data):
 


@@ -688,6 +717,11 @@ Event packet context (all fields are optional, specified by TSDL meta-data):
   while (or before) writing the first event and while (or after) writing the
   last event in the packet. The inclusive range between these timestamps should
   include all event timestamps assigned to events contained within the packet.
   while (or before) writing the first event and while (or after) writing the
   last event in the packet. The inclusive range between these timestamps should
   include all event timestamps assigned to events contained within the packet.

+  The timestamp at the beginning of an event packet is guaranteed to be
+  below or equal the timestamp at the end of that event packet.
+  The timestamp at the end of an event packet is guaranteed to be below
+  or equal the timestamps at the end of any following packet within the
+  same stream. See Section 8. Clocks for more detail.

 - Events discarded count
   - Snapshot of a per-stream free-running counter, counting the number of
     events discarded that were supposed to be written in the stream after
 - Events discarded count
   - Snapshot of a per-stream free-running counter, counting the number of
     events discarded that were supposed to be written in the stream after


@@ -760,8 +794,8 @@ struct event_packet_context {
   uint32_t stream_packet_count;
   uint32_t events_discarded;
   uint32_t cpu_id;
   uint32_t stream_packet_count;
   uint32_t events_discarded;
   uint32_t cpu_id;

-  uint32_t/uint16_t content_size;
-  uint32_t/uint16_t packet_size;
+  uint64_t/uint32_t/uint16_t content_size;
+  uint64_t/uint32_t/uint16_t packet_size;

   uint8_t  compression_scheme;
   uint8_t  encryption_scheme;
   uint8_t  checksum_scheme;
   uint8_t  compression_scheme;
   uint8_t  encryption_scheme;
   uint8_t  checksum_scheme;


@@ -772,17 +806,22 @@ struct event_packet_context {
 
 The overall structure of an event is:
 
 
 The overall structure of an event is:
 

-1 - Stream Packet Context (as specified by the stream meta-data)
- 2 - Event Header (as specified by the stream meta-data)
-  3 - Stream Event Context (as specified by the stream meta-data)
-   4 - Event Context (as specified by the event meta-data)
-    5 - Event Payload (as specified by the event meta-data)
+1 - Event Header (as specified by the stream meta-data)
+ 2 - Stream Event Context (as specified by the stream meta-data)
+  3 - Event Context (as specified by the event meta-data)
+   4 - Event Payload (as specified by the event meta-data)

 
 This structure defines an implicit dynamic scoping, where variants
 located in inner structures (those with a higher number in the listing
 above) can refer to the fields of outer structures (with lower number in
 the listing above). See Section 7.3 TSDL Scopes for more detail.
 
 
 This structure defines an implicit dynamic scoping, where variants
 located in inner structures (those with a higher number in the listing
 above) can refer to the fields of outer structures (with lower number in
 the listing above). See Section 7.3 TSDL Scopes for more detail.
 

+The total length of an event is defined as the difference between the
+end of its Event Payload and the end of the previous event's Event
+Payload. Therefore, it includes the event header alignment padding, and
+all its fields and their respective alignment padding. Events of length
+0 are forbidden.
+

 6.1 Event Header
 
 Event headers can be described within the meta-data. We hereby propose, as an
 6.1 Event Header
 
 Event headers can be described within the meta-data. We hereby propose, as an


@@ -805,11 +844,13 @@ array is then set to 1.
 Types uintX_t represent an X-bit unsigned integer, as declared with
 either:
 
 Types uintX_t represent an X-bit unsigned integer, as declared with
 either:
 

-  typealias integer { size = X; align = X; signed = false } := uintX_t;
+  typealias integer { size = X; align = X; signed = false; } := uintX_t;

 
     or
 
 
     or
 

-  typealias integer { size = X; align = 1; signed = false } := uintX_t;
+  typealias integer { size = X; align = 1; signed = false; } := uintX_t;
+
+For more information about timestamp fields, see Section 8. Clocks.

 
 6.1.1 Type 1 - Few event IDs
 
 
 6.1.1 Type 1 - Few event IDs
 


@@ -867,7 +908,7 @@ struct event_header_2 {
 } align(16);   /* or align(8) */
 
 
 } align(16);   /* or align(8) */
 
 

-6.2 Event Context
+6.2 Stream Event Context and Event Context

 
 The event context contains information relative to the current event.
 The choice and meaning of this information is specified by the TSDL
 
 The event context contains information relative to the current event.
 The choice and meaning of this information is specified by the TSDL


@@ -973,12 +1014,13 @@ beginning of the file. This magic number is also used to detect the
 endianness of the architecture by trying to read the CTF magic number
 and its counterpart in reversed endianness. The events within the
 meta-data stream have no event header nor event context. Each event only
 endianness of the architecture by trying to read the CTF magic number
 and its counterpart in reversed endianness. The events within the
 meta-data stream have no event header nor event context. Each event only

-contains a "sequence" payload, which is a sequence of bits using the
-"trace.packet.header.content_size" field as a placeholder for its length
-(the packet header size should be substracted). The formatting of this
-sequence of bits is a plain-text representation of the TSDL description.
-Each meta-data packet start with a special packet header, specific to
-the meta-data stream, which contains, exactly:
+contains a special "sequence" payload, which is a sequence of bits which
+length is implicitly calculated by using the
+"trace.packet.header.content_size" field, minus the packet header size.
+The formatting of this sequence of bits is a plain-text representation
+of the TSDL description.  Each meta-data packet start with a special
+packet header, specific to the meta-data stream, which contains,
+exactly:

 
 struct metadata_packet_header {
   uint32_t magic;                      /* 0x75D11D57 */
 
 struct metadata_packet_header {
   uint32_t magic;                      /* 0x75D11D57 */


@@ -994,7 +1036,7 @@ struct metadata_packet_header {
 };
 
 The packet-based meta-data can be converted to a text-only meta-data by
 };
 
 The packet-based meta-data can be converted to a text-only meta-data by

-concatenating all the strings in contains.
+concatenating all the strings it contains.

 
 In the textual representation of the meta-data, the text contained
 within "/*" and "*/", as well as within "//" and end of line, are
 
 In the textual representation of the meta-data, the text contained
 within "/*" and "*/", as well as within "//" and end of line, are


@@ -1155,6 +1197,7 @@ event {
   id = value;                  /* Numeric identifier within the stream */
   stream_id = stream_id;
   loglevel = value;
   id = value;                  /* Numeric identifier within the stream */
   stream_id = stream_id;
   loglevel = value;

+  model.emf.uri = "string";

   context := struct {
     ...
   };
   context := struct {
     ...
   };


@@ -1163,6 +1206,14 @@ event {
   };
 };
 
   };
 };
 

+callsite {
+  name = "event_name";
+  func = "func_name";
+  file = "myfile.c";
+  line = 39;
+  ip = 0x40096c;
+};
+

 /* More detail on types in section 4. Types */
 
 /*
 /* More detail on types in section 4. Types */
 
 /*


@@ -1339,10 +1390,11 @@ stream {
 };
 
 For a N-bit integer type referring to a clock, if the integer overflows
 };
 
 For a N-bit integer type referring to a clock, if the integer overflows

-compared to the N low order bits of the clock prior value, then it is
-assumed that one, and only one, overflow occurred. It is therefore
-important that events encoding time on a small number of bits happen
-frequently enough to detect when more than one N-bit overflow occurs.
+compared to the N low order bits of the clock prior value found in the
+same stream, then it is assumed that one, and only one, overflow
+occurred. It is therefore important that events encoding time on a small
+number of bits happen frequently enough to detect when more than one
+N-bit overflow occurs.

 
 In a packet context, clock field names ending with "_begin" and "_end"
 have a special meaning: this refers to the time-stamps at, respectively,
 
 In a packet context, clock field names ending with "_begin" and "_end"
 have a special meaning: this refers to the time-stamps at, respectively,


@@ -1418,6 +1470,7 @@ token:
 keyword: is one of
 
 align
 keyword: is one of
 
 align

+callsite

 const
 char
 clock
 const
 char
 clock


@@ -1741,6 +1794,7 @@ ctf-specifier:
        stream { ctf-assignment-expression-list-opt }
        env { ctf-assignment-expression-list-opt }
        trace { ctf-assignment-expression-list-opt }
        stream { ctf-assignment-expression-list-opt }
        env { ctf-assignment-expression-list-opt }
        trace { ctf-assignment-expression-list-opt }

+       callsite { ctf-assignment-expression-list-opt }

        typealias declaration-specifiers abstract-declarator-list type-assignment-operator declaration-specifiers abstract-declarator-list
        typealias declaration-specifiers abstract-declarator-list type-assignment-operator declarator-list
 
        typealias declaration-specifiers abstract-declarator-list type-assignment-operator declaration-specifiers abstract-declarator-list
        typealias declaration-specifiers abstract-declarator-list type-assignment-operator declarator-list