Jonathan Rajotte | 23 Jan 19:22 2015

[PATCH lttng-ust] Fix: java-agent: out-of-tree path to java manifest

This should also be backported to stable-2.6.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien <at> efficios.com>
---
 liblttng-ust-java-agent/java/Makefile.am | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/liblttng-ust-java-agent/java/Makefile.am b/liblttng-ust-java-agent/java/Makefile.am
index bcf6abe..399b533 100644
--- a/liblttng-ust-java-agent/java/Makefile.am
+++ b/liblttng-ust-java-agent/java/Makefile.am
 <at>  <at>  -4,7 +4,7  <at>  <at>  pkgpath = org/lttng/ust/agent
 pkgpath_old = org/lttng/ust/jul

 jarfile_version = 1.0.0
-jarfile_manifest = $(pkgpath)/Manifest.txt
+jarfile_manifest = $(srcdir)/$(pkgpath)/Manifest.txt
 jarfile_symlink = liblttng-ust-agent.jar
 jarfile = liblttng-ust-agent-$(jarfile_version).jar

--

-- 
1.9.1
Yan Grange | 23 Jan 17:00 2015
Picon

python bindings for babel trace example fails

Good afternoon,

I have been able to get lttng running on a machine and now would like to do some experiments with babeltrace.
I’d like to write out a ctf file using babeltrace. Therefore I wanted to try out the babeltrace python
bindings out and since you provide a set of examples, of which one is about writing a ctf, I wanted to try that
one out.

When I use the latste release of babeltrace (1.2.4), the library fails on the following line:

print("Clock name is \"{}\"".format(clock.name))

because it seems like the getter for clock.name doesn’t exist. to solve the issues I have with this
example, I have checked out the most recent version of babeltrace from the git repo. If I run the ctf_writer
using python, I get

yan <at> paul ~/build_bbt/babeltrace/bindings/python/examples $ python3 ctf_writer.py
Writing trace at /tmp/tmptlhq3i
Clock name is "A_clock"
Clock description is "Simple clock"
Clock frequency is 1000000000
Clock precision is 1
Clock offset_seconds is 0
Clock offset is 0
Clock is absolute: False
Clock time is 0
Clock UUID is 874be90c-6c68-46ee-ac0d-6142cafe23f5

Fields in default packet context:
<class 'babeltrace.CTFWriter.IntegerFieldDeclaration'> timestamp_begin
<class 'babeltrace.CTFWriter.IntegerFieldDeclaration'> timestamp_end
(Continue reading)

Mathieu Desnoyers | 23 Jan 17:28 2015

[PATCH lttng-tools 1/2] Fix: uninitialized return value

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers <at> efficios.com>
---
 src/bin/lttng-sessiond/ust-app.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index 41a6d39..bdee8e6 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
 <at>  <at>  -4132,7 +4132,7  <at>  <at>  static
 int ust_app_flush_session(struct ltt_ust_session *usess)

 {
-	int ret;
+	int ret = 0;

 	DBG("Flushing session buffers for all ust apps");

 <at>  <at>  -4173,7 +4173,6  <at>  <at>  int ust_app_flush_session(struct ltt_ust_session *usess)
 			/* Push metadata. */
 			(void) push_metadata(ust_session_reg, usess->consumer);
 		}
-		ret = 0;
 		break;
 	}
 	case LTTNG_BUFFER_PER_PID:
 <at>  <at>  -4192,6 +4191,7  <at>  <at>  int ust_app_flush_session(struct ltt_ust_session *usess)
 		break;
 	}
 	default:
(Continue reading)

Anand Neeli | 23 Jan 11:16 2015
Picon

enable-channel switch timer not getting updated

Hi All,
I'm using 2.4.1 version.
and i dont see switch timer being updated in output of "lttng list <session>"
i'm using default subbuf-size and default sub-buf count.

output :

$ # lttng list mys4
Tracing session mys4: [active]
    Trace path: net4://127.0.0.1:5342/ [data: 5343]

=== Domain: UST global ===
Buffer type: per PID
Channels:
-------------
- myc4: [enabled]

    Attributes:
      overwrite mode: 0
      subbufers size: 4096
      number of subbufers: 4
      switch timer interval: 0   <<<<<<<< doesnt show switch-timer
      read timer interval: 0
      output: mmap()

    Events:
      * (type: tracepoint) [enabled] [has exclusions]


i used following commands to create session

lttng  --no-sessiond create mys4 --live 200000 -U net://localhost

lttng enable-channel myc4 --userspace --buffers-pid -s mys4 --tracefile-size 8388608 --tracefile-count 8 --switch-timer 1000

lttng enable-event --channel myc4 --userspace --all --exclude 'ust_libc:*' -s mys4

lttng start mys4


Please let me know if i missed anything.

Thanks,

Anand Neeli

_______________________________________________
lttng-dev mailing list
lttng-dev <at> lists.lttng.org
http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
Wang Nan | 23 Jan 10:35 2015

My experience on perf, CTF and TraceCompass, and some suggection.

Hi folks,

I'd like to share my first tuning experience with perf, ctf and
TraceCompass here, and I hope my experience helpful to diamon.org. Most
part of this mail is talking about my work. If you don't
interest in it, you can directly jump to conclusion part.

*My Task*

What I'm working on is finding the reason why CPU idle rate is high when
we benchmarking a database. I think it should be a very simple task:
tracing scheduling and system calls, finding the previous syscall issued
before idle, then based on statistics, collecting some user spaces call
stack, I can give an answer. I use perf to collect trace,
perf-convert-to-ctf to get ctf output and TraceCompass for
visualization.

*My Experience*

First of all I use perf to collect trace:

 # perf record -a -e sched:* -e raw_syscalls:* sleep 1

then

 # perf data convert --to-ctf out.ctf

Which is simple. However, raw_syscalls:* tracepoints export less
information than syscalls:* tracepoints. Without them I have to manually
find syscall name from syscall id. I prefer to use:

 # perf record -a -e sched:* -e syscalls:* sleep 1

However there are some bugs and I have to make some patches. They are
posted and being disscussed currently, those bugs are still exist
upstream.

Then I need to convert perf.data to ctf. It tooks 140.57s to convert
2598513 samples, which are collected during only 1 second execution. My
working server has 64 2.0GHz Intel Xeon cores, but perf conversion
utilizes only 1 of them. I think this is another thing can be improved.

The next step is visualization. Output ctf trace can be opened with
TraceCompass without problem. The most important views for me should be
resources view (I use them to check CPU usage) and control flow view (I
use them to check thread activities).

The first uncomfortable thing is TraceCompass' slow response time. For
the trace I mentioned above, on resource view, after I click on CPU
idle area, I have to wait more than 10 seconds for event list updating
to get the previous event before the idle area.

Then I found through resources view that perf itself tooks lots of CPU
time. In my case 33.5% samples are generated by perf itself. One core is
dedicated to perf and never idle or taken by others. I think this should
be another thing needs to be improved: perf should give a way to
blacklist itself when tracing all CPUs.

TraceCompass doesn't recognize syscall:* tracepoints as CPU status
changing point. I have to also catch raw_syscall:*, and which doubles
the number of samples.

Finally I found the syscall which cause idle. However I need to write a
script to do statistics. TraceCompass itself is lack a mean to count
different events in my way.

The next thing I should do is to find the calltrace which issue the
syscall. This time TraceCompass won't help, mostly because perf
convertion now doesn't support converting calltrace.

*Conclusion*

I suggest perf and TraceCompass to think about following improvements:

 1. Reducing the cost of perf recording. There are one third events are
    generated by perf itself in my case. Is it possible that perf could
    provide an ability that blacklist itself and collect all other
    events?

 2. Improving perf converting performance. Converting perf.data to CTF is
    slow, but it should be offline most of the time. We can utilize the
    abilities multi-core server to make it working in parallel.

 3. Improving TraceCompass responding performance, especially when
    synchronizing different views.

 4. Support converting userspace call trace. I think perf side should already
    have a plan on it.

 5. Ad-Hoc visualization and statistics. Currently TraceCompass only
    support dwaring pre-defined events and processes. When I try to
    capture syscalls:*, I won't get benefit from TraceCompass because it
    doesn't know them. I believe that during system tuning we will
    finally get somewhere unable to be pre-defined by TraceCompass
    designer. Therefore give users abilities to define their own events
    and model should be much helpful.

Thank you.
Mattias Johansson | 23 Jan 10:29 2015
Picon

Strange sequence of events

Hi lttng-people!

I have been using lttng to make a combined kernel and userspace trace and I can't make sense of a simple sequence of events. I am using a two core cpu, a custom distro (by yocto), linux kernel version is 3.12.15 with the PREEMPT RT patches, the lttng probe module lttng-probe-sched loaded.
This is my strange sequence:

[13:26:17.542825060] (+0.000003659) unit1 sched_switch: { cpu_id = 1 }, { pid = 2390 }, { prev_comm = "ThreadA", prev_tid = 2547, prev_prio = -19, prev_state = 1024, next_comm = "KernelThreadB", next_tid = 2410, next_prio = -51 }
[13:26:17.542831008] (+0.000005948) unit1 sched_migrate_task: { cpu_id = 0 }, { pid = 2408 }, { comm = "ThreadA", tid = 2547, prio = -19, orig_cpu = 1, dest_cpu = 0 }
[13:26:17.542837060] (+0.000003256) unit1 ust_event:my_ust_event: { cpu_id = 1 }, { vtid = 2547 }, { }

ThreadA makes the userspace trace event 'my_ust_event'.

What is strange to me is either the timestamp of 'my_ust_event' is "wrong" (it should have been a time before the sched_switch), or the cpu_id of the ust_event is "wrong" (it should be 0 since ThreadA has been migrated to cpu_id 0 at 13:26:17.542831008).

Or am I interpreting the sequence wrong?

Or could it be that the my_ust_event itself got interrupted and had already sampled the cpu_id, and after the migration completed the event, thus the trace is "correct"?

Thanks!
/Mattias

_______________________________________________
lttng-dev mailing list
lttng-dev <at> lists.lttng.org
http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
Jonathan Rajotte | 22 Jan 22:06 2015

[PATCH lttng-tool] Test: do not run ust dependent tests on make check

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien <at> efficios.com>
---
 configure.ac      | 1 +
 tests/Makefile.am | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/configure.ac b/configure.ac
index 8d1ff86..954059e 100644
--- a/configure.ac
+++ b/configure.ac
 <at>  <at>  -251,6 +251,7  <at>  <at>  AS_IF([test "x$lttng_ust_support" = "xyes"], [
 	)
 ])
 AM_CONDITIONAL([HAVE_LIBLTTNG_UST_CTL], [test "x$lttng_ust_ctl_found" = xyes])
+AM_CONDITIONAL([HAVE_LTTNG_UST], [test "x$lttng_ust_support" = xyes])
 AC_CHECK_FUNCS([sched_getcpu sysconf sync_file_range])

 # check for dlopen
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 2f1f1c3..b52d91b 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
 <at>  <at>  -2,14 +2,21  <at>  <at>  SUBDIRS = utils regression unit stress

 installcheck-am:
 	./run.sh unit_tests
+
+if HAVE_LTTNG_UST
 	./run.sh fast_regression
+endif
+
 if USE_PYTHON
 	./run.sh with_bindings_regression
 endif

 check-am:
 	./run.sh unit_tests
+if HAVE_LTTNG_UST
 	./run.sh fast_regression
+endif
+
 if USE_PYTHON
 	./run.sh with_bindings_regression
 endif
--

-- 
1.9.1
Philippe Proulx | 22 Jan 05:51 2015
Picon

[PATCH ctf] Modernize CTF specification using Markdown

Content is unchanged, with the exception of a few
minor typos fixed here and there.

Signed-off-by: Philippe Proulx <eeppeliteloop <at> gmail.com>
---
 common-trace-format-specification.md  | 2035 +++++++++++++++++++++++++++++++++
 common-trace-format-specification.txt | 1823 -----------------------------
 2 files changed, 2035 insertions(+), 1823 deletions(-)
 create mode 100644 common-trace-format-specification.md
 delete mode 100644 common-trace-format-specification.txt

diff --git a/common-trace-format-specification.md b/common-trace-format-specification.md
new file mode 100644
index 0000000..d984176
--- /dev/null
+++ b/common-trace-format-specification.md
 <at>  <at>  -0,0 +1,2035  <at>  <at> 
+# Common Trace Format (CTF) Specification (v1.8.2)
+
+**Author**: Mathieu Desnoyers, [EfficiOS Inc.](http://www.efficios.com/)
+
+The goal of the present document is to specify a trace format that suits
+the needs of the embedded, telecom, high-performance and kernel
+communities. It is based on the
+[Common Trace Format Requirements (v1.4)](http://git.efficios.com/?p=ctf.git;a=blob_plain;f=common-trace-format-reqs.txt;hb=master)
+document. It is designed to allow traces to be natively generated by the
+Linux kernel, Linux user space applications written in C/C++, and
+hardware components. One major element of CTF is the Trace Stream
+Description Language (TSDL) which flexibility enables description of
+various binary trace stream layouts.
+
+The latest version of this document can be found at:
+
+  * Git: `git clone git://git.efficios.com/ctf.git`
+  * [Gitweb](http://git.efficios.com/?p=ctf.git)
+
+A reference implementation of a library to read and write this trace
+format is being implemented within the
+[Babeltrace](http://www.efficios.com/babeltrace) project, a converter
+between trace formats. The development tree is available at:
+
+  * Git: `git clone git://git.efficios.com/babeltrace.git`
+  * [Gitweb](http://git.efficios.com/?p=babeltrace.git)
+
+The [CE Workgroup](http://www.linuxfoundation.org/collaborate/workgroups/celf)
+of the Linux Foundation, [Ericsson](http://www.ericsson.com/), and
+[EfficiOS](http://www.efficios.com/) have sponsored this work.
+
+**Contents**:
+
+    1. Preliminary definitions
+    2. High-level representation of a trace
+    3. Event stream
+    4. Types
+      4.1 Basic types
+        4.1.1 Type inheritance
+        4.1.2 Alignment
+        4.1.3 Byte order
+        4.1.4 Size
+        4.1.5 Integers
+        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
+    5. Event packet header
+      5.1 Event packet header description
+      5.2 Event packet context description
+    6. Event structure
+      6.1 Event header
+        6.1.1 Type 1: few event IDs
+        6.1.2 Type 2: many event IDs
+      6.2 Stream event context and event context
+      6.3 Event payload
+        6.3.1 Padding
+        6.3.2 Alignment
+    7. Trace Stream Description Language (TSDL)
+      7.1 Metadata
+      7.2 Declaration vs definition
+      7.3 TSDL scopes
+        7.3.1 Lexical scope
+        7.3.2 Static and dynamic scopes
+      7.4 TSDL examples
+    8. Clocks
+    A. Helper macros
+    B. Stream header rationale
+    C. TSDL Grammar
+      C.1 Lexical grammar
+        C.1.1 Lexical elements
+        C.1.2 Keywords
+        C.1.3 Identifiers
+        C.1.4 Universal character names
+        C.1.5 Constants
+        C.1.6 String literals
+        C.1.7 Punctuators
+      C.2 Phrase structure grammar
+        C.2.2 Declarations:
+        C.2.3 CTF-specific declarations
+
+
+## 1. Preliminary definitions
+
+  * **Event trace**: an ordered sequence of events.
+  * **Event stream**: an ordered sequence of events, containing a
+    subset of the trace event types.
+  * **Event packet**: a sequence of physically contiguous events within
+    an event stream.
+  * **Event**: this is the basic entry in a trace. Also known as
+    a _trace record_.
+    * An **event identifier** (ID) relates to the class (a type) of
+      event within an event stream, e.g. event `irq_entry`.
+    * An **event** (or event record) relates to a specific instance of
+      an event class, e.g. event `irq_entry`, at time _X_, on CPU _Y_.
+  * Source architecture: architecture writing the trace.
+  * Reader architecture: architecture reading the trace.
+
+
+## 2. High-level representation of a trace
+
+A _trace_ is divided into multiple event streams. Each event stream
+contains a subset of the trace event types.
+
+The final output of the trace, after its generation and optional
+transport over the network, is expected to be either on permanent or
+temporary storage in a virtual file system. Because each event stream
+is appended to while a trace is being recorded, each is associated with
+a distinct set of files for output. Therefore, a stored trace can be
+represented as a directory containing zero, one or more files
+per stream.
+
+Metadata description associated with the trace contains information on
+trace event types expressed in the _Trace Stream Description Language_
+(TSDL). This language describes:
+
+  * Trace version
+  * Types available
+  * Per-trace event header description
+  * Per-stream event header description
+  * Per-stream event context description
+  * Per-event
+    * Event type to stream mapping
+    * Event type to name mapping
+    * Event type to ID mapping
+    * Event context description
+    * Event fields description
+
+
+## 3. Event stream
+
+An _event stream_ can be divided into contiguous event packets of
+variable size. An event packet can contain a certain amount of padding
+at the end. The stream header is repeated at the beginning of each
+event packet. The rationale for the event stream design choices is
+explained in [Stream header rationale](#specB).
+
+The event stream header will therefore be referred to as the
+_event packet header_ throughout the rest of this document.
+
+
+## 4. Types
+
+Types are organized as type classes. Each type class belong to either
+of two kind of types: _basic types_ or _compound types_.
+
+
+### 4.1 Basic types
+
+A basic type is a scalar type, as described in this section. It
+includes integers, GNU/C bitfields, enumerations, and floating
+point values.
+
+
+#### 4.1.1 Type inheritance
+
+Type specifications can be inherited to allow deriving types from a
+type class. For example, see the uint32_t named type derived from the
+[_integer_ type](#spec4.1.5) class. Types have a precise binary
+representation in the trace. A type class has methods to read and write
+these types, but must be derived into a type to be usable in an event
+field.
+
+
+#### 4.1.2 Alignment
+
+We define _byte-packed_ types as aligned on the byte size, namely 8-bit.
+We define _bit-packed_ types as following on the next bit, as defined
+by the [Integers](#spec4.1.5) section.
+
+Each basic type must specify its alignment, in bits. Examples of
+possible alignments are: bit-packed (`align = 1`), byte-packed
+(`align = 8`), or word-aligned (e.g. `align = 32` or `align = 64`).
+The choice depends on the architecture preference and compactness vs
+performance trade-offs of the implementation. Architectures providing
+fast unaligned write byte-packed basic types to save space, aligning
+each type on byte boundaries (8-bit). Architectures with slow unaligned
+writes align types on specific alignment values. If no specific
+alignment is declared for a type, it is assumed to be bit-packed for
+integers with size not multiple of 8 bits and for gcc bitfields. All
+other basic types are byte-packed 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.
+
+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 metadata attribute representation of a specific alignment:
+
+~~~ tsdl
+align = /* value in bits */;
+~~~
+
+#### 4.1.3 Byte order
+
+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 metadata representation:
+
+~~~ tsdl
+/* network and be are aliases */
+byte_order = /* native OR network OR be OR le */;
+~~~
+
+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 multiplied by `CHAR_BIT`. We require the size of `char`
+and `unsigned char` types (`CHAR_BIT`) to be fixed to 8 bits for
+cross-endianness compatibility.
+
+TSDL metadata representation:
+
+~~~ tsdl
+size = /* value is in bits */;
+~~~
+
+
+#### 4.1.5 Integers
+
+Signed integers are represented in two-complement. Integer alignment,
+size, signedness and byte ordering are defined in the TSDL metadata.
+Integers aligned on byte size (8-bit) and with length multiple of byte
+size (8-bit) correspond to the C99 standard integers. In addition,
+integers with alignment and/or size that are _not_ a multiple of the
+byte size are permitted; these correspond to the C99 standard bitfields,
+with the added specification that the CTF integer bitfields have a fixed
+binary representation. Integer size needs to be a positive integer.
+Integers of size 0 are **forbidden**. An MIT-licensed reference
+implementation of the CTF portable bitfields is available
+[here](http://git.efficios.com/?p=babeltrace.git;a=blob;f=include/babeltrace/bitfield.h).
+
+Binary representation of integers:
+
+  * On little and big endian:
+    * Within a byte, high bits correspond to an integer high bits, and
+      low bits correspond to low bits
+  * On little endian:
+    * Integer across multiple bytes are placed from the less significant
+      to the most significant
+    * Consecutive integers are placed from lower bits to higher bits
+      (even within a byte)
+  * On big endian:
+    * Integer across multiple bytes are placed from the most significant
+      to the less significant
+    * Consecutive integers are placed from higher bits to lower bits
+      (even within a byte)
+
+This binary representation is derived from the bitfield implementation
+in GCC for little and big endian. However, contrary to what GCC does,
+integers can cross units boundaries (no padding is required). Padding
+can be [explicitly added](#spec4.1.6) to follow the GCC layout if needed.
+
+TSDL metadata representation:
+
+~~~ tsdl
+integer {
+    signed = /* true OR false */;                     /* default: false */
+    byte_order = /* native OR network OR be OR le */; /* default: native */
+    size = /* value in bits */;                       /* no default */
+    align = /* value in bits */;
+
+    /* base used for pretty-printing output; default: decimal */
+    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 */
+    encoding = /* none or UTF8 or ASCII */;           /* default: none */
+}
+~~~
+
+Example of type inheritance (creation of a `uint32_t` named type):
+
+~~~ tsdl
+typealias integer {
+    size = 32;
+    signed = false;
+    align = 32;
+} := uint32_t;
+~~~
+
+Definition of a named 5-bit signed bitfield:
+
+~~~ tsdl
+typealias integer {
+    size = 5;
+    signed = true;
+    align = 1;
+} := int5_t;
+~~~
+
+The character encoding field can be used to specify that the integer
+must be printed as a text character when read. e.g.:
+
+~~~ tsdl
+typealias integer {
+    size = 8;
+    align = 8;
+    signed = false;
+    encoding = UTF8;
+} := utf_char;
+~~~
+
+#### 4.1.6 GNU/C bitfields
+
+The GNU/C bitfields follow closely the integer representation, with a
+particularity on alignment: if a bitfield cannot fit in the current
+unit, the unit is padded and the bitfield starts at the following unit.
+The unit size is defined by the size of the type `unit_type`.
+
+TSDL metadata representation:
+
+~~~ tsdl
+unit_type name:size;
+~~~
+
+As an example, the following structure declared in C compiled by GCC:
+
+~~~ tsdl
+struct example {
+    short a:12;
+    short b:5;
+};
+~~~
+
+The example structure is aligned on the largest element (short). The
+second bitfield would be aligned on the next unit boundary, because it
+would not fit in the current unit.
+
+
+#### 4.1.7 Floating point
+
+The floating point values byte ordering is defined in the TSDL metadata.
+
+Floating point values follow the IEEE 754-2008 standard interchange
+formats. Description of the floating point values include the exponent
+and mantissa size in bits. Some requirements are imposed on the
+floating point values:
+
+* `FLT_RADIX` must be 2.
+* `mant_dig` is the number of digits represented in the mantissa. It is
+  specified by the ISO C99 standard, section 5.2.4, as `FLT_MANT_DIG`,
+  `DBL_MANT_DIG` and `LDBL_MANT_DIG` as defined by `<float.h>`.
+* `exp_dig` is the number of digits represented in the exponent. Given
+  that `mant_dig` is one bit more than its actual size in bits (leading
+  1 is not needed) and also given that the sign bit always takes one
+  bit, `exp_dig` can be specified as:
+  * `sizeof(float) * CHAR_BIT - FLT_MANT_DIG`
+  * `sizeof(double) * CHAR_BIT - DBL_MANT_DIG`
+  * `sizeof(long double) * CHAR_BIT - LDBL_MANT_DIG`
+
+TSDL metadata representation:
+
+~~~ tsdl
+floating_point {
+    exp_dig = /* value */;
+    mant_dig = /* value */;
+    byte_order = /* native OR network OR be OR le */;
+    align = /* value */;
+}
+~~~
+
+Example of type inheritance:
+
+~~~ tsdl
+typealias floating_point {
+    exp_dig = 8;         /* sizeof(float) * CHAR_BIT - FLT_MANT_DIG */
+    mant_dig = 24;       /* FLT_MANT_DIG */
+    byte_order = native;
+    align = 32;
+} := float;
+~~~
+
+TODO: define NaN, +inf, -inf behavior.
+
+Bit-packed, byte-packed or larger alignments can be used for floating
+point values, similarly to integers.
+
+
+#### 4.1.8 Enumerations
+
+Enumerations are a mapping between an integer type and a table of
+strings. The numerical representation of the enumeration follows the
+integer type specified by the metadata. The enumeration mapping table
+is detailed in the enumeration description within the metadata. The
+mapping table maps inclusive value ranges (or single values) to strings.
+Instead of being limited to simple `value -> string` mappings, these
+enumerations map `[ start_value ... end_value ] -> string`, which map
+inclusive ranges of values to strings. An enumeration from the C
+language can be represented in this format by having the same
+`start_value` and `end_value` for each mapping, which is in fact a
+range of size 1. This single-value range is supported without repeating
+the start and end values with the `value = string` declaration.
+Enumerations need to contain at least one entry.
+
+~~~ tsdl
+enum name : integer_type {
+    somestring          = /* start_value1 */ ... /* end_value1 */,
+    "other string"      = /* start_value2 */ ... /* end_value2 */,
+    yet_another_string,   /* will be assigned to end_value2 + 1 */
+    "some other string" = /* value */,
+    /* ... */
+}
+~~~
+
+If the values are omitted, the enumeration starts at 0 and increment
+of 1 for each entry. An entry with omitted value that follows a range
+entry takes as value the `end_value` of the previous range + 1:
+
+~~~ tsdl
+enum name : unsigned int {
+    ZERO,
+    ONE,
+    TWO,
+    TEN = 10,
+    ELEVEN,
+}
+~~~
+
+Overlapping ranges within a single enumeration are implementation
+defined.
+
+A nameless enumeration can be declared as a field type or as part of
+a `typedef`:
+
+~~~ tsdl
+enum : integer_type {
+    /* ... */
+}
+~~~
+
+Enumerations omitting the container type `: integer_type` use the `int`
+type (for compatibility with C99). The `int` type _must be_ previously
+declared, e.g.:
+
+~~~ tsdl
+typealias integer { size = 32; align = 32; signed = true; } := int;
+
+enum {
+    /* ... */
+}
+~~~
+
+### 4.2 Compound types
+
+Compound are aggregation of type declarations. Compound types include
+structures, variant, arrays, sequences, and strings.
+
+
+#### 4.2.1 Structures
+
+Structures are aligned on the largest alignment required by basic types
+contained within the structure. (This follows the ISO/C standard for
+structures)
+
+TSDL metadata representation of a named structure:
+
+~~~ tsdl
+struct name {
+    field_type field_name;
+    field_type field_name;
+    /* ... */
+};
+~~~
+
+Example:
+
+~~~ tsdl
+struct example {
+    integer {                   /* nameless type */
+        size = 16;
+        signed = true;
+        align = 16;
+    } first_field_name;
+    uint64_t second_field_name; /* named type declared in the metadata */
+};
+~~~
+
+The fields are placed in a sequence next to each other. They each
+possess a field name, which is a unique identifier within the structure.
+The identifier is not allowed to use any [reserved keyword](#specC.1.2).
+Replacing reserved keywords with underscore-prefixed field names is
+**recommended**. Fields starting with an underscore should have their
+leading underscore removed by the CTF trace readers.
+
+A nameless structure can be declared as a field type or as part of
+a `typedef`:
+
+~~~ tsdl
+struct {
+    /* ... */
+}
+~~~
+
+Alignment for a structure compound type can be forced to a minimum
+value by adding an `align` specifier after the declaration of a
+structure body. This attribute is read as: `align(value)`. The value is
+specified in bits. The structure will be aligned on the maximum value
+between this attribute and the alignment required by the basic types
+contained within the structure. e.g.
+
+~~~ tsdl
+struct {
+    /* ... */
+} align(32)
+~~~
+
+#### 4.2.2 Variants (discriminated/tagged unions)
+
+A CTF variant is a selection between different types. A CTF variant must
+always be defined within the scope of a structure or within fields
+contained within a structure (defined recursively). A _tag_ enumeration
+field must appear in either the same static scope, prior to the variant
+field (in field declaration order), in an upper static scope, or in an
+upper dynamic scope (see [Static and dynamic scopes](#spec7.3.2)).
+The type selection is indicated by the mapping from the enumeration
+value to the string used as variant 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. It is not required that each enumeration mapping appears
+as variant type tag field. It is also not required that each variant
+type tag appears as enumeration mapping. However, it is required that
+any enumeration mapping encountered within a stream has a matching
+variant type tag field.
+
+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
+[reserved keyword](#C.1.2). Replacing reserved keywords with
+underscore-prefixed field names is recommended. Fields starting with an
+underscore should have their leading underscore removed by the CTF trace
+readers.
+
+A named variant declaration followed by its definition within a
+structure declaration:
+
+~~~ tsdl
+variant name {
+    field_type sel1;
+    field_type sel2;
+    field_type sel3;
+    /* ... */
+};
+
+struct {
+    enum : integer_type { sel1, sel2, sel3, /* ... */ } tag_field;
+    /* ... */
+    variant name <tag_field> v;
+}
+~~~
+
+An unnamed variant definition within a structure is expressed by the
+following TSDL metadata:
+
+~~~ tsdl
+struct {
+    enum : integer_type { sel1, sel2, sel3, /* ... */ } tag_field;
+    /* ... */
+    variant <tag_field> {
+        field_type sel1;
+        field_type sel2;
+        field_type sel3;
+        /* ... */
+    } v;
+}
+~~~
+
+Example of a named variant within a sequence that refers to a single
+tag field:
+
+~~~ tsdl
+variant example {
+    uint32_t a;
+    uint64_t b;
+    short c;
+};
+
+struct {
+    enum : uint2_t { a, b, c } choice;
+    unsigned int seqlen;
+    variant example <choice> v[seqlen];
+}
+~~~
+
+Example of an unnamed variant:
+
+~~~ tsdl
+struct {
+    enum : uint2_t { a, b, c, d } choice;
+
+    /* Unrelated fields can be added between the variant and its tag */
+    int32_t somevalue;
+    variant <choice> {
+        uint32_t a;
+        uint64_t b;
+        short c;
+        struct {
+            unsigned int field1;
+            uint64_t field2;
+        } d;
+    } s;
+}
+~~~
+
+Example of an unnamed variant within an array:
+
+~~~ tsdl
+struct {
+    enum : uint2_t { a, b, c } choice;
+    variant <choice> {
+        uint32_t a;
+        uint64_t b;
+        short c;
+    } v[10];
+}
+~~~
+
+Example of a variant type definition within a structure, where the
+defined type is then declared within an array of structures. This
+variant refers to a tag located in an upper static scope. This example
+clearly shows that a variant type definition referring to the tag `x`
+uses the closest preceding field from the static scope of the type
+definition.
+
+~~~ tsdl
+struct {
+    enum : uint2_t { a, b, c, d } x;
+
+    /*
+     * "x" refers to the preceding "x" enumeration in the
+     * static scope of the type definition.
+     */
+    typedef variant <x> {
+      uint32_t a;
+      uint64_t b;
+      short c;
+    } example_variant;
+
+    struct {
+      enum : int { x, y, z } x; /* This enumeration is not used by "v". */
+
+      /* "v" uses the "enum : uint2_t { a, b, c, d }" tag. */
+      example_variant v;
+    } a[10];
+}
+~~~
+
+
+#### 4.2.3 Arrays
+
+Arrays are fixed-length. Their length is declared in the type
+declaration within the metadata. They contain an array of _inner type_
+elements, which can refer to any type not containing the type of the
+array being declared (no circular dependency). The length is the number
+of elements in an array.
+
+TSDL metadata representation of a named array:
+
+~~~ tsdl
+typedef elem_type name[/* length */];
+~~~
+
+A nameless array can be declared as a field type within a
+structure, e.g.:
+
+~~~ tsdl
+uint8_t field_name[10];
+~~~
+
+Arrays are always aligned on their element alignment requirement.
+
+
+#### 4.2.4 Sequences
+
+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 [Static and dynamic scopes](#spec7.3.2)). This length field represents
+the number of elements in the sequence. The sequence per se is an
+array of _inner type_ elements.
+
+TSDL metadata representation for a sequence type definition:
+
+~~~ tsdl
+struct {
+    unsigned int length_field;
+    typedef elem_type typename[length_field];
+    typename seq_field_name;
+}
+~~~
+
+A sequence can also be declared as a field type, e.g.:
+
+~~~ tsdl
+struct {
+    unsigned int length_field;
+    long seq_field_name[length_field];
+}
+~~~
+
+Multiple sequences can refer to the same length field, and these length
+fields can be in a different upper dynamic scope, e.g., assuming the
+`stream.event.header` defines:
+
+~~~ tsdl
+stream {
+    /* ... */
+    id = 1;
+    event.header := struct {
+        uint16_t seq_len;
+    };
+};
+
+event {
+    /* ... */
+    stream_id = 1;
+    fields := struct {
+        long seq_a[stream.event.header.seq_len];
+        char seq_b[stream.event.header.seq_len];
+    };
+};
+~~~
+
+The sequence elements follow the [array](#spec4.2.3) specifications.
+
+
+#### 4.2.5 Strings
+
+Strings are an array of _bytes_ of variable size and are terminated by
+a `'\0'` "NULL" character. Their encoding is described in the TSDL
+metadata. In absence of encoding attribute information, the default
+encoding is UTF-8.
+
+TSDL metadata representation of a named string type:
+
+~~~ tsdl
+typealias string {
+    encoding = /* UTF8 OR ASCII */;
+} := name;
+~~~
+
+A nameless string type can be declared as a field type:
+
+~~~ tsdl
+string field_name; /* use default UTF8 encoding */
+~~~
+
+Strings are always aligned on byte size.
+
+
+## 5. Event packet header
+
+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 metadata.
+
+Event packet header (all fields are optional, specified by
+TSDL metadata):
+
+  * **Magic number** (CTF magic number: 0xC1FC1FC1) specifies that this is
+    a CTF packet. This magic number is optional, but when present, it
+    should come at the very beginning of the packet.
+  * **Trace UUID**, used to ensure the event packet match the metadata used.
+    Note: we cannot use a metadata checksum in every cases instead of a
+    UUID because metadata can be appended to while tracing is active.
+    This field is optional.
+  * **Stream ID**, used as reference to stream description in metadata.
+    This field is optional if there is only one stream description in
+    the metadata, but becomes required if there are more than one
+    stream in the TSDL metadata description.
+
+Event packet context (all fields are optional, specified by
+TSDL metadata):
+
+  * Event packet **content size** (in bits).
+  * Event packet **size** (in bits, includes padding).
+  * Event packet content checksum. Checksum excludes the event packet
+    header.
+  * Per-stream event **packet sequence count** (to deal with UDP packet
+    loss). The number of significant sequence counter bits should also
+    be present, so wrap-arounds are dealt with correctly.
+  * Time-stamp at the beginning and timestamp at the end of the event
+    packet. Both timestamps are written in the packet header, but
+    sampled respectively 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 [Clocks](#spec8) 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 the last event in
+    the event packet. Note: producer-consumer buffer full condition can
+    fill the current event packet with padding so we know exactly where
+    events have been discarded. However, if the buffer full condition
+    chooses not to fill the current event packet with padding, all we
+    know about the timestamp range in which the events have been
+    discarded is that it is somewhere between the beginning and the end
+    of the packet.
+  * Lossless **compression scheme** used for the event packet content.
+    Applied directly to raw data. New types of compression can be added
+    in following versions of the format.
+    * 0: no compression scheme
+    * 1: bzip2
+    * 2: gzip
+    * 3: xz
+  * **Cypher** used for the event packet content. Applied after
+    compression.
+    * 0: no encryption
+    * 1: AES
+  * **Checksum scheme** used for the event packet content. Applied after
+    encryption.
+    * 0: no checksum
+    * 1: md5
+    * 2: sha1
+    * 3: crc32
+
+
+### 5.1 Event packet header description
+
+The event packet header layout is indicated by the
+`trace.packet.header` field. Here is a recommended structure type for
+the packet header with the fields typically expected (although these
+fields are each optional):
+
+~~~ tsdl
+struct event_packet_header {
+    uint32_t magic;
+    uint8_t  uuid[16];
+    uint32_t stream_id;
+};
+
+trace {
+    /* ... */
+    packet.header := struct event_packet_header;
+};
+~~~
+
+If the magic number is not present, tools such as `file` will have no
+mean to discover the file type.
+
+If the uuid is not present, no validation that the metadata actually
+corresponds to the stream is performed.
+
+If the stream_id packet header field is missing, the trace can only
+contain a single stream. Its `id` field can be left out, and its events
+don't need to declare a `stream_id` field.
+
+
+### 5.2 Event packet context description
+
+Event packet context example. These are declared within the stream
+declaration in the metadata. All these fields are optional. If the
+packet size field is missing, the whole stream only contains a single
+packet. If the content size field is missing, the packet is filled
+(no padding). The content and packet sizes include all headers.
+
+An example event packet context type:
+
+~~~ tsdl
+struct event_packet_context {
+    uint64_t timestamp_begin;
+    uint64_t timestamp_end;
+    uint32_t checksum;
+    uint32_t stream_packet_count;
+    uint32_t events_discarded;
+    uint32_t cpu_id;
+    uint64_t content_size;
+    uint64_t packet_size;
+    uint8_t  compression_scheme;
+    uint8_t  encryption_scheme;
+    uint8_t  checksum_scheme;
+};
+~~~
+
+
+## 6. Event Structure
+
+The overall structure of an event is:
+
+  1. Event header (as specified by the stream metadata)
+  2. Stream event context (as specified by the stream metadata)
+  3. Event context (as specified by the event metadata)
+  4. Event payload (as specified by the event metadata)
+
+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 [TSDL scopes](#spec7.3) 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 metadata. We hereby propose,
+as an example, two types of events headers. Type 1 accommodates streams
+with less than 31 event IDs. Type 2 accommodates streams with 31 or
+more event IDs.
+
+One major factor can vary between streams: the number of event IDs
+assigned to a stream. Luckily, this information tends to stay
+relatively constant (modulo event registration while trace is being
+recorded), so we can specify different representations for streams
+containing few event IDs and streams containing many event IDs, so we
+end up representing the event ID and timestamp as densely as possible
+in each case.
+
+The header is extended in the rare occasions where the information
+cannot be represented in the ranges available in the standard event
+header. They are also used in the rare occasions where the data
+required for a field could not be collected: the flag corresponding to
+the missing field within the `missing_fields` array is then set to 1.
+
+Types `uintX_t` represent an `X`-bit unsigned integer, as declared with
+either:
+
+~~~ tsdl
+typealias integer {
+    size = /* X */;
+    align = /* X */;
+    signed = false;
+} := uintX_t;
+~~~
+
+or
+
+~~~ tsdl
+typealias integer {
+    size = /* X */;
+    align = 1;
+    signed = false;
+} := uintX_t;
+~~~
+
+For more information about timestamp fields, see [Clocks](#spec8).
+
+
+#### 6.1.1 Type 1: few event IDs
+
+  * Aligned on 32-bit (or 8-bit if byte-packed, depending on the
+    architecture preference)
+  * Native architecture byte ordering
+  * For `compact` selection, fixed size of 32 bits
+  * For "extended" selection, size depends on the architecture and
+    variant alignment
+
+~~~ tsdl
+struct event_header_1 {
+    /*
+     * id: range: 0 - 30.
+     * id 31 is reserved to indicate an extended header.
+     */
+    enum : uint5_t { compact = 0 ... 30, extended = 31 } id;
+    variant <id> {
+        struct {
+            uint27_t timestamp;
+        } compact;
+        struct {
+            uint32_t id;        /* 32-bit event IDs */
+            uint64_t timestamp; /* 64-bit timestamps */
+        } extended;
+    } v;
+} align(32); /* or align(8) */
+~~~
+
+
+#### 6.1.2 Type 2: many event IDs
+
+  * Aligned on 16-bit (or 8-bit if byte-packed, depending on the
+    architecture preference)
+  * Native architecture byte ordering
+  * For `compact` selection, size depends on the architecture and
+    variant alignment
+  * For `extended` selection, size depends on the architecture and
+    variant alignment
+
+~~~ tsdl
+struct event_header_2 {
+    /*
+     * id: range: 0 - 65534.
+     * id 65535 is reserved to indicate an extended header.
+     */
+    enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;
+    variant <id> {
+        struct {
+            uint32_t timestamp;
+        } compact;
+        struct {
+            uint32_t id;        /* 32-bit event IDs */
+            uint64_t timestamp; /* 64-bit timestamps */
+        } extended;
+    } v;
+} align(16); /* or align(8) */
+~~~
+
+
+### 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
+stream and event metadata descriptions. The stream context is applied
+to all events within the stream. The stream context structure follows
+the event header. The event context is applied to specific events. Its
+structure follows the stream context structure.
+
+An example of stream-level event context is to save the event payload
+size with each event, or to save the current PID with each event.
+These are declared within the stream declaration within the metadata:
+
+~~~ tsdl
+stream {
+    /* ... */
+    event.context := struct {
+        uint pid;
+        uint16_t payload_size;
+    };
+};
+~~~
+
+An example of event-specific event context is to declare a bitmap of
+missing fields, only appended after the stream event context if the
+extended event header is selected. `NR_FIELDS` is the number of fields
+within the event (a numeric value).
+
+~~~ tsdl
+event {
+    context := struct {
+        variant <id> {
+            struct { } compact;
+            struct {
+                /* missing event fields bitmap */
+                uint1_t missing_fields[NR_FIELDS];
+            } extended;
+        } v;
+    };
+    /* ... */
+}
+~~~
+
+
+### 6.3 Event payload
+
+An event payload contains fields specific to a given event type. The
+fields belonging to an event type are described in the event-specific
+metadata within a structure type.
+
+
+#### 6.3.1 Padding
+
+No padding at the end of the event payload. This differs from the ISO/C
+standard for structures, but follows the CTF standard for structures.
+In a trace, even though it makes sense to align the beginning of a
+structure, it really makes no sense to add padding at the end of the
+structure, because structures are usually not followed by a structure
+of the same type.
+
+This trick can be done by adding a zero-length `end` field at the end
+of the C structures, and by using the offset of this field rather than
+using `sizeof()` when calculating the size of a structure
+(see [Helper macros](#specA)).
+
+
+#### 6.3.2 Alignment
+
+The event payload is aligned on the largest alignment required by types
+contained within the payload. This follows the ISO/C standard for
+structures.
+
+
+## 7. Trace Stream Description Language (TSDL)
+
+The Trace Stream Description Language (TSDL) allows expression of the
+binary trace streams layout in a C99-like Domain Specific Language
+(DSL).
+
+
+### 7.1 Meta-data
+
+The trace stream layout description is located in the trace metadata.
+The metadata is itself located in a stream identified by its name:
+`metadata`.
+
+The metadata description can be expressed in two different formats:
+text-only and packet-based. The text-only description facilitates
+generation of metadata and provides a convenient way to enter the
+metadata information by hand. The packet-based metadata provides the
+CTF stream packet facilities (checksumming, compression, encryption,
+network-readiness) for metadata stream generated and transported by a
+tracer.
+
+The text-only metadata file is a plain-text TSDL description. This file
+must begin with the following characters to identify the file as a CTF
+TSDL text-based metadata file (without the double-quotes):
+
+~~~ text
+"/* CTF"
+~~~
+
+It must be followed by a space, and the version of the specification
+followed by the CTF trace, e.g.:
+
+~~~ text
+" 1.8"
+~~~
+
+These characters allow automated discovery of file type and CTF
+specification version. They are interpreted as a the beginning of a
+comment by the TSDL metadata parser. The comment can be continued to
+contain extra commented characters before it is closed.
+
+The packet-based metadata is made of _metadata packets_, which each
+start with a metadata packet header. The packet-based metadata
+description is detected by reading the magic number 0x75D11D57 at the
+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
+metadata stream have no event header nor event context. Each event only
+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 metadata packet start with a special
+packet header, specific to the metadata stream, which contains,
+exactly:
+
+~~~ tsdl
+struct metadata_packet_header {
+    uint32_t magic;              /* 0x75D11D57 */
+    uint8_t  uuid[16];           /* Unique Universal Identifier */
+    uint32_t checksum;           /* 0 if unused */
+    uint32_t content_size;       /* in bits */
+    uint32_t packet_size;        /* in bits */
+    uint8_t  compression_scheme; /* 0 if unused */
+    uint8_t  encryption_scheme;  /* 0 if unused */
+    uint8_t  checksum_scheme;    /* 0 if unused */
+    uint8_t  major;              /* CTF spec version major number */
+    uint8_t  minor;              /* CTF spec version minor number */
+};
+~~~
+
+The packet-based metadata can be converted to a text-only metadata by
+concatenating all the strings it contains.
+
+In the textual representation of the metadata, the text contained
+within `/*` and `*/`, as well as within `//` and end of line, are
+treated as comments. Boolean values can be represented as `true`,
+`TRUE`, or `1` for true, and `false`, `FALSE`, or `0` for false. Within
+the string-based metadata description, the trace UUID is represented as
+a string of hexadecimal digits and dashes `-`. In the event packet
+header, the trace UUID is represented as an array of bytes.
+
+
+### 7.2 Declaration vs definition
+
+A declaration associates a layout to a type, without specifying where
+this type is located in the event [structure hierarchy](#spec6).
+This therefore includes `typedef`, `typealias`, as well as all type
+specifiers. In certain circumstances (`typedef`, structure field and
+variant field), a declaration is followed by a declarator, which specify
+the newly defined type name (for `typedef`), or the field name (for
+declarations located within structure and variants). Array and sequence,
+declared with square brackets (`[` `]`), are part of the declarator,
+similarly to C99. The enumeration base type is specified by
+`: enum_base`, which is part of the type specifier. The variant tag
+name, specified between `<` `>`, is also part of the type specifier.
+
+A definition associates a type to a location in the event
+[structure hierarchy](#spec6). This association is denoted by `:=`,
+as shown in [TSDL scopes](#spec7.3).
+
+
+### 7.3 TSDL scopes
+
+TSDL uses three different types of scoping: a lexical scope is used for
+declarations and type definitions, and static and dynamic scopes are
+used for variants references to tag fields (with relative and absolute
+path lookups) and for sequence references to length fields.
+
+
+#### 7.3.1 Lexical Scope
+
+Each of `trace`, `env`, `stream`, `event`, `struct` and `variant` have
+their own nestable declaration scope, within which types can be declared
+using `typedef` and `typealias`. A root declaration scope also contains
+all declarations located outside of any of the aforementioned
+declarations. An inner declaration scope can refer to type declared
+within its container lexical scope prior to the inner declaration scope.
+Redefinition of a typedef or typealias is not valid, although hiding an
+upper scope typedef or typealias is allowed within a sub-scope.
+
+
+#### 7.3.2 Static and dynamic scopes
+
+A local static scope consists in the scope generated by the declaration
+of fields within a compound type. A static scope is a local static scope
+augmented with the nested sub-static-scopes it contains.
+
+A dynamic scope consists in the static scope augmented with the
+implicit [event structure](#spec6) definition hierarchy.
+
+Multiple declarations of the same field name within a local static scope
+is not valid. It is however valid to re-use the same field name in
+different local scopes.
+
+Nested static and dynamic scopes form lookup paths. These are used for
+variant tag and sequence length references. They are used at the variant
+and sequence definition site to look up the location of the tag field
+associated with a variant, and to lookup up the location of the length
+field associated with a sequence.
+
+Variants and sequences can refer to a tag field either using a relative
+path or an absolute path. The relative path is relative to the scope in
+which the variant or sequence performing the lookup is located.
+Relative paths are only allowed to lookup within the same static scope,
+which includes its nested static scopes. Lookups targeting parent static
+scopes need to be performed with an absolute path.
+
+Absolute path lookups use the full path including the dynamic scope
+followed by a `.` and then the static scope. Therefore, variants (or
+sequences) in lower levels in the dynamic scope (e.g., event context)
+can refer to a tag (or length) field located in upper levels
+(e.g., in the event header) by specifying, in this case, the associated
+tag with `<stream.event.header.field_name>`. This allows, for instance,
+the event context to define a variant referring to the `id` field of
+the event header as selector.
+
+The dynamic scope prefixes are thus:
+
+  * Trace environment: `<env. >`
+  * Trace packet header: `<trace.packet.header. >`
+  * Stream packet context: `<stream.packet.context. >`
+  * Event header: `<stream.event.header. >`
+  * Stream event context: `<stream.event.context. >`
+  * Event context: `<event.context. >`
+  * Event payload: `<event.fields. >`
+
+The target dynamic scope must be specified explicitly when referring to
+a field outside of the static scope (absolute scope reference). No
+conflict can occur between relative and dynamic paths, because the
+keywords `trace`, `stream`, and `event` are reserved, and thus not
+permitted as field names. It is recommended that field names clashing
+with CTF and C99 reserved keywords use an underscore prefix to
+eliminate the risk of generating a description containing an invalid
+field name. Consequently, fields starting with an underscore should have
+their leading underscore removed by the CTF trace readers.
+
+The information available in the dynamic scopes can be thought of as the
+current tracing context. At trace production, information about the
+current context is saved into the specified scope field levels. At trace
+consumption, for each event, the current trace context is therefore
+readable by accessing the upper dynamic scopes.
+
+
+### 7.4 TSDL examples
+
+The grammar representing the TSDL metadata is presented in
+[TSDL grammar](#specC). This section presents a rather lighter reading that
+consists in examples of TSDL metadata, with template values.
+
+The stream ID can be left out if there is only one stream in the
+trace. The event `id` field can be left out if there is only one event
+in a stream.
+
+~~~ tsdl
+trace {
+    major = /* value */;            /* CTF spec version major number */
+    minor = /* value */;            /* CTF spec version minor number */
+    uuid = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa";  /* Trace UUID */
+    byte_order = /* be OR le */;    /* Endianness (required) */
+    packet.header := struct {
+        uint32_t magic;
+        uint8_t  uuid[16];
+        uint32_t stream_id;
+    };
+};
+
+/*
+ * The "env" (environment) scope contains assignment expressions. The
+ * field names and content are implementation-defined.
+ */
+env {
+    pid = /* value */;    /* example */
+    proc_name = "name";   /* example */
+    /* ... */
+};
+
+stream {
+    id = /* stream_id */;
+    /* Type 1 - Few event IDs; Type 2 - Many event IDs. See section 6.1. */
+    event.header := /* event_header_1 OR event_header_2 */;
+    event.context := struct {
+        /* ... */
+    };
+    packet.context := struct {
+        /* ... */
+    };
+};
+
+event {
+    name = "event_name";
+    id = /* value */;            /* Numeric identifier within the stream */
+    stream_id = /* stream_id */;
+    loglevel = /* value */;
+    model.emf.uri = "string";
+    context := struct {
+        /* ... */
+    };
+    fields := struct {
+        /* ... */
+    };
+};
+
+callsite {
+    name = "event_name";
+    func = "func_name";
+    file = "myfile.c";
+    line = 39;
+    ip = 0x40096c;
+};
+~~~
+
+More detail on [types](#spec4):
+
+~~~ tsdl
+/*
+ * Named types:
+ *
+ * Type declarations behave similarly to the C standard.
+ */
+
+typedef aliased_type_specifiers new_type_declarators;
+
+/* e.g.: typedef struct example new_type_name[10]; */
+
+/*
+ * typealias
+ *
+ * The "typealias" declaration can be used to give a name (including
+ * pointer declarator specifier) to a type. It should also be used to
+ * map basic C types (float, int, unsigned long, ...) to a CTF type.
+ * Typealias is a superset of "typedef": it also allows assignment of a
+ * simple variable identifier to a type.
+ */
+
+typealias type_class {
+    /* ... */
+} := type_specifiers type_declarator;
+
+/*
+ * e.g.:
+ * typealias integer {
+ *   size = 32;
+ *   align = 32;
+ *   signed = false;
+ * } := struct page *;
+ *
+ * typealias integer {
+ *  size = 32;
+ *  align = 32;
+ *  signed = true;
+ * } := int;
+ */
+
+struct name {
+    /* ... */
+};
+
+variant name {
+    /* ... */
+};
+
+enum name : integer_type {
+    /* ... */
+};
+~~~
+
+Unnamed types, contained within compound type fields, `typedef` or
+`typealias`:
+
+~~~ tsdl
+struct {
+    /* ... */
+}
+~~~
+
+~~~ tsdl
+struct {
+    /* ... */
+} align(value)
+~~~
+
+~~~ tsdl
+variant {
+    /* ... */
+}
+~~~
+
+~~~ tsdl
+enum : integer_type {
+    /* ... */
+}
+~~~
+
+~~~ tsdl
+typedef type new_type[length];
+
+struct {
+    type field_name[length];
+}
+~~~
+
+~~~ tsdl
+typedef type new_type[length_type];
+
+struct {
+    type field_name[length_type];
+}
+~~~
+
+~~~ tsdl
+integer {
+    /* ... */
+}
+~~~
+
+~~~ tsdl
+floating_point {
+    /* ... */
+}
+~~~
+
+~~~ tsdl
+struct {
+    integer_type field_name:size;   /* GNU/C bitfield */
+}
+~~~
+
+~~~ tsdl
+struct {
+    string field_name;
+}
+~~~
+
+
+## 8. Clocks
+
+Clock metadata allows to describe the clock topology of the system, as
+well as to detail each clock parameter. In absence of clock description,
+it is assumed that all fields named `timestamp` use the same clock
+source, which increments once per nanosecond.
+
+Describing a clock and how it is used by streams is threefold: first,
+the clock and clock topology should be described in a `clock`
+description block, e.g.:
+
+~~~ tsdl
+clock {
+    name = cycle_counter_sync;
+    uuid = "62189bee-96dc-11e0-91a8-cfa3d89f3923";
+    description = "Cycle counter synchronized across CPUs";
+    freq = 1000000000;           /* frequency, in Hz */
+    /* precision in seconds is: 1000 * (1/freq) */
+    precision = 1000;
+    /*
+     * clock value offset from Epoch is:
+     * offset_s + (offset * (1/freq))
+     */
+    offset_s = 1326476837;
+    offset = 897235420;
+    absolute = FALSE;
+};
+~~~
+
+The mandatory `name` field specifies the name of the clock identifier,
+which can later be used as a reference. The optional field `uuid` is
+the unique identifier of the clock. It can be used to correlate
+different traces that use the same clock. An optional textual
+description string can be added with the `description` field. The
+`freq` field is the initial frequency of the clock, in Hz. If the
+`freq` field is not present, the frequency is assumed to be 1000000000
+(providing clock increment of 1 ns). The optional `precision` field
+details the uncertainty on the clock measurements, in (1/freq) units.
+The `offset_s` and `offset` fields indicate the offset from
+POSIX.1 Epoch, 1970-01-01 00:00:00 +0000 (UTC), to the zero of value
+of the clock. The `offset_s` field is in seconds. The `offset` field is
+in (1/freq) units. If any of the `offset_s` or `offset` field is not
+present, it is assigned the 0 value. The field `absolute` is `TRUE` if
+the clock is a global reference across different clock UUID
+(e.g. NTP time). Otherwise, `absolute` is `FALSE`, and the clock can
+be considered as synchronized only with other clocks that have the same
+UUID.
+
+Secondly, a reference to this clock should be added within an integer
+type:
+
+~~~ tsdl
+typealias integer {
+    size = 64; align = 1; signed = false;
+    map = clock.cycle_counter_sync.value;
+} := uint64_ccnt_t;
+~~~
+
+Thirdly, stream declarations can reference the clock they use as a
+timestamp source:
+
+~~~ tsdl
+struct packet_context {
+    uint64_ccnt_t ccnt_begin;
+    uint64_ccnt_t ccnt_end;
+    /* ... */
+};
+
+stream {
+    /* ... */
+    event.header := struct {
+        uint64_ccnt_t timestamp;
+        /* ... */
+    };
+    packet.context := struct packet_context;
+};
+~~~
+
+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 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 timestamps at, respectively,
+the beginning and the end of each packet.
+
+
+## A. Helper macros
+
+The two following macros keep track of the size of a GNU/C structure
+without padding at the end by placing HEADER_END as the last field.
+A one byte end field is used for C90 compatibility (C99 flexible arrays
+could be used here). Note that this does not affect the effective
+structure size, which should always be calculated with the
+`header_sizeof()` helper.
+
+~~~ c
+#define HEADER_END          char end_field
+#define header_sizeof(type) offsetof(typeof(type), end_field)
+~~~
+
+## B. Stream header rationale
+
+An event stream is divided in contiguous event packets of variable
+size. These subdivisions allow the trace analyzer to perform a fast
+binary search by time within the stream (typically requiring to index
+only the event packet headers) without reading the whole stream. These
+subdivisions have a variable size to eliminate the need to transfer the
+event packet padding when partially filled event packets must be sent
+when streaming a trace for live viewing/analysis. An event packet can
+contain a certain amount of padding at the end. Dividing streams into
+event packets is also useful for network streaming over UDP and flight
+recorder mode tracing (a whole event packet can be swapped out of the
+buffer atomically for reading).
+
+The stream header is repeated at the beginning of each event packet to
+allow flexibility in terms of:
+
+  * streaming support
+  * allowing arbitrary buffers to be discarded without making the trace
+    unreadable
+  * allow UDP packet loss handling by either dealing with missing event packet
+    or asking for re-transmission
+  * transparently support flight recorder mode
+  * transparently support crash dump
+
+
+## C. TSDL Grammar
+
+~~~ c
+/*
+ * Common Trace Format (CTF) Trace Stream Description Language (TSDL) Grammar.
+ *
+ * Inspired from the C99 grammar:
+ * http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf (Annex A)
+ * and c++1x grammar (draft)
+ * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3291.pdf (Annex A)
+ *
+ * Specialized for CTF needs by including only constant and declarations from
+ * C99 (excluding function declarations), and by adding support for variants,
+ * sequences and CTF-specific specifiers. Enumeration container types
+ * semantic is inspired from c++1x enum-base.
+ */
+~~~
+
+
+### C.1 Lexical grammar
+
+
+#### C.1.1 Lexical elements
+
+~~~ text
+token:
+    keyword
+    identifier
+    constant
+    string-literal
+    punctuator
+~~~
+
+#### C.1.2 Keywords
+
+~~~ text
+keyword: is one of
+
+align
+callsite
+const
+char
+clock
+double
+enum
+env
+event
+floating_point
+float
+integer
+int
+long
+short
+signed
+stream
+string
+struct
+trace
+typealias
+typedef
+unsigned
+variant
+void
+_Bool
+_Complex
+_Imaginary
+~~~
+
+
+#### C.1.3 Identifiers
+
+~~~ text
+identifier:
+    identifier-nondigit
+    identifier identifier-nondigit
+    identifier digit
+
+identifier-nondigit:
+    nondigit
+    universal-character-name
+    any other implementation-defined characters
+
+nondigit:
+    _
+    [a-zA-Z]    /* regular expression */
+
+digit:
+    [0-9]        /* regular expression */
+~~~
+
+
+#### C.1.4 Universal character names
+
+~~~ text
+universal-character-name:
+    \u hex-quad
+    \U hex-quad hex-quad
+
+hex-quad:
+    hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit
+~~~
+
+
+##### C.1.5 Constants
+
+~~~ text
+constant:
+    integer-constant
+    enumeration-constant
+    character-constant
+
+integer-constant:
+    decimal-constant integer-suffix-opt
+    octal-constant integer-suffix-opt
+    hexadecimal-constant integer-suffix-opt
+
+decimal-constant:
+    nonzero-digit
+    decimal-constant digit
+
+octal-constant:
+    0
+    octal-constant octal-digit
+
+hexadecimal-constant:
+    hexadecimal-prefix hexadecimal-digit
+    hexadecimal-constant hexadecimal-digit
+
+hexadecimal-prefix:
+    0x
+    0X
+
+nonzero-digit:
+    [1-9]
+
+integer-suffix:
+    unsigned-suffix long-suffix-opt
+    unsigned-suffix long-long-suffix
+    long-suffix unsigned-suffix-opt
+    long-long-suffix unsigned-suffix-opt
+
+unsigned-suffix:
+    u
+    U
+
+long-suffix:
+    l
+    L
+
+long-long-suffix:
+    ll
+    LL
+
+enumeration-constant:
+    identifier
+    string-literal
+
+character-constant:
+    ' c-char-sequence '
+    L' c-char-sequence '
+
+c-char-sequence:
+    c-char
+    c-char-sequence c-char
+
+c-char:
+    any member of source charset except single-quote ('), backslash
+    (\), or new-line character.
+    escape-sequence
+
+escape-sequence:
+    simple-escape-sequence
+    octal-escape-sequence
+    hexadecimal-escape-sequence
+    universal-character-name
+
+simple-escape-sequence: one of
+    \' \" \? \\ \a \b \f \n \r \t \v
+
+octal-escape-sequence:
+    \ octal-digit
+    \ octal-digit octal-digit
+    \ octal-digit octal-digit octal-digit
+
+hexadecimal-escape-sequence:
+    \x hexadecimal-digit
+    hexadecimal-escape-sequence hexadecimal-digit
+~~~
+
+
+#### C.1.6 String literals
+
+~~~ text
+string-literal:
+    " s-char-sequence-opt "
+    L" s-char-sequence-opt "
+
+s-char-sequence:
+    s-char
+    s-char-sequence s-char
+
+s-char:
+    any member of source charset except double-quote ("), backslash
+    (\), or new-line character.
+    escape-sequence
+~~~
+
+
+#### C.1.7 Punctuators
+
+~~~ text
+punctuator: one of
+    [ ] ( ) { } . -> * + - < > : ; ... = ,
+~~~
+
+
+### C.2 Phrase structure grammar
+
+~~~ text
+primary-expression:
+    identifier
+    constant
+    string-literal
+    ( unary-expression )
+
+postfix-expression:
+    primary-expression
+    postfix-expression [ unary-expression ]
+    postfix-expression . identifier
+    postfix-expressoin -> identifier
+
+unary-expression:
+    postfix-expression
+    unary-operator postfix-expression
+
+unary-operator: one of
+    + -
+
+assignment-operator:
+    =
+
+type-assignment-operator:
+    :=
+
+constant-expression-range:
+    unary-expression ... unary-expression
+~~~
+
+
+#### C.2.2 Declarations:
+
+~~~ text
+declaration:
+    declaration-specifiers declarator-list-opt ;
+    ctf-specifier ;
+
+declaration-specifiers:
+    storage-class-specifier declaration-specifiers-opt
+    type-specifier declaration-specifiers-opt
+    type-qualifier declaration-specifiers-opt
+
+declarator-list:
+    declarator
+    declarator-list , declarator
+
+abstract-declarator-list:
+    abstract-declarator
+    abstract-declarator-list , abstract-declarator
+
+storage-class-specifier:
+    typedef
+
+type-specifier:
+    void
+    char
+    short
+    int
+    long
+    float
+    double
+    signed
+    unsigned
+    _Bool
+    _Complex
+    _Imaginary
+    struct-specifier
+    variant-specifier
+    enum-specifier
+    typedef-name
+    ctf-type-specifier
+
+align-attribute:
+    align ( unary-expression )
+
+struct-specifier:
+    struct identifier-opt { struct-or-variant-declaration-list-opt } align-attribute-opt
+    struct identifier align-attribute-opt
+
+struct-or-variant-declaration-list:
+    struct-or-variant-declaration
+    struct-or-variant-declaration-list struct-or-variant-declaration
+
+struct-or-variant-declaration:
+    specifier-qualifier-list struct-or-variant-declarator-list ;
+    declaration-specifiers-opt storage-class-specifier declaration-specifiers-opt 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 ;
+
+specifier-qualifier-list:
+    type-specifier specifier-qualifier-list-opt
+    type-qualifier specifier-qualifier-list-opt
+
+struct-or-variant-declarator-list:
+    struct-or-variant-declarator
+    struct-or-variant-declarator-list , struct-or-variant-declarator
+
+struct-or-variant-declarator:
+    declarator
+    declarator-opt : unary-expression
+
+variant-specifier:
+    variant identifier-opt variant-tag-opt { struct-or-variant-declaration-list }
+    variant identifier variant-tag
+
+variant-tag:
+    < unary-expression >
+
+enum-specifier:
+    enum identifier-opt { enumerator-list }
+    enum identifier-opt { enumerator-list , }
+    enum identifier
+    enum identifier-opt : declaration-specifiers { enumerator-list }
+    enum identifier-opt : declaration-specifiers { enumerator-list , }
+
+enumerator-list:
+    enumerator
+    enumerator-list , enumerator
+
+enumerator:
+    enumeration-constant
+    enumeration-constant assignment-operator unary-expression
+    enumeration-constant assignment-operator constant-expression-range
+
+type-qualifier:
+    const
+
+declarator:
+    pointer-opt direct-declarator
+
+direct-declarator:
+    identifier
+    ( declarator )
+    direct-declarator [ unary-expression ]
+
+abstract-declarator:
+    pointer-opt direct-abstract-declarator
+
+direct-abstract-declarator:
+    identifier-opt
+    ( abstract-declarator )
+    direct-abstract-declarator [ unary-expression ]
+    direct-abstract-declarator [ ]
+
+pointer:
+    * type-qualifier-list-opt
+    * type-qualifier-list-opt pointer
+
+type-qualifier-list:
+    type-qualifier
+    type-qualifier-list type-qualifier
+
+typedef-name:
+    identifier
+~~~
+
+
+#### C.2.3 CTF-specific declarations
+
+~~~ text
+ctf-specifier:
+    clock { ctf-assignment-expression-list-opt }
+    event { 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
+
+ctf-type-specifier:
+    floating_point { ctf-assignment-expression-list-opt }
+    integer { ctf-assignment-expression-list-opt }
+    string { ctf-assignment-expression-list-opt }
+    string
+
+ctf-assignment-expression-list:
+    ctf-assignment-expression ;
+    ctf-assignment-expression-list ctf-assignment-expression ;
+
+ctf-assignment-expression:
+    unary-expression assignment-operator unary-expression
+    unary-expression type-assignment-operator type-specifier
+    declaration-specifiers-opt storage-class-specifier declaration-specifiers-opt 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
+~~~
diff --git a/common-trace-format-specification.txt b/common-trace-format-specification.txt
deleted file mode 100644
index 5568a27..0000000
--- a/common-trace-format-specification.txt
+++ /dev/null
 <at>  <at>  -1,1823 +0,0  <at>  <at> 
-Common Trace Format (CTF) Specification (v1.8.2)
-
-Mathieu Desnoyers, EfficiOS Inc.
-
-The goal of the present document is to specify a trace format that suits the
-needs of the embedded, telecom, high-performance and kernel communities. It is
-based on the Common Trace Format Requirements (v1.4) document. It is designed to
-allow traces to be natively generated by the Linux kernel, Linux user-space
-applications written in C/C++, and hardware components. One major element of
-CTF is the Trace Stream Description Language (TSDL) which flexibility
-enables description of various binary trace stream layouts.
-
-The latest version of this document can be found at:
-
-  git tree:   git://git.efficios.com/ctf.git
-  gitweb:     http://git.efficios.com/?p=ctf.git
-
-A reference implementation of a library to read and write this trace format is
-being implemented within the BabelTrace project, a converter between trace
-formats. The development tree is available at:
-
-  git tree:   git://git.efficios.com/babeltrace.git
-  gitweb:     http://git.efficios.com/?p=babeltrace.git
-
-The CE Workgroup of the Linux Foundation, Ericsson, and EfficiOS have
-sponsored this work.
-
-
-Table of Contents
-
-1. Preliminary definitions
-2. High-level representation of a trace
-3. Event stream
-4. Types
-   4.1 Basic types
-       4.1.1 Type inheritance
-       4.1.2 Alignment
-       4.1.3 Byte order
-       4.1.4 Size
-       4.1.5 Integers
-       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
-5. Event Packet Header
-   5.1 Event Packet Header Description
-   5.2 Event Packet Context Description
-6. Event Structure
-   6.1 Event Header
-       6.1.1 Type 1 - Few event IDs
-       6.1.2 Type 2 - Many event IDs
-   6.2 Stream Event Context and Event Context
-   6.3 Event Payload
-       6.3.1 Padding
-       6.3.2 Alignment
-7. Trace Stream Description Language (TSDL)
-   7.1 Meta-data
-   7.2 Declaration vs Definition
-   7.3 TSDL Scopes
-       7.3.1 Lexical Scope
-       7.3.2 Static and Dynamic Scopes
-   7.4 TSDL Examples
-8. Clocks
-
-
-1. Preliminary definitions
-
-  - Event Trace: An ordered sequence of events.
-  - Event Stream: An ordered sequence of events, containing a subset of the
-                  trace event types.
-  - Event Packet: A sequence of physically contiguous events within an event
-                  stream.
-  - Event: This is the basic entry in a trace. (aka: a trace record).
-    - An event identifier (ID) relates to the class (a type) of event within
-      an event stream.
-        e.g. event: irq_entry.
-    - An event (or event record) relates to a specific instance of an event
-      class.
-        e.g. event: irq_entry, at time X, on CPU Y
-  - Source Architecture: Architecture writing the trace.
-  - Reader Architecture: Architecture reading the trace.
-
-
-2. High-level representation of a trace
-
-A trace is divided into multiple event streams. Each event stream contains a
-subset of the trace event types.
-
-The final output of the trace, after its generation and optional transport over
-the network, is expected to be either on permanent or temporary storage in a
-virtual file system. Because each event stream is appended to while a trace is
-being recorded, each is associated with a distinct set of files for
-output. Therefore, a stored trace can be represented as a directory
-containing zero, one or more files per stream.
-
-Meta-data description associated with the trace contains information on
-trace event types expressed in the Trace Stream Description Language
-(TSDL). This language describes:
-
-- Trace version.
-- Types available.
-- Per-trace event header description.
-- Per-stream event header description.
-- Per-stream event context description.
-- Per-event
-  - Event type to stream mapping.
-  - Event type to name mapping.
-  - Event type to ID mapping.
-  - Event context description.
-  - Event fields description.
-
-
-3. Event stream
-
-An event stream can be divided into contiguous event packets of variable
-size. An event packet can contain a certain amount of padding at the
-end. The stream header is repeated at the beginning of each event
-packet. The rationale for the event stream design choices is explained
-in Appendix B. Stream Header Rationale.
-
-The event stream header will therefore be referred to as the "event packet
-header" throughout the rest of this document.
-
-
-4. Types
-
-Types are organized as type classes. Each type class belong to either of two
-kind of types: basic types or compound types.
-
-4.1 Basic types
-
-A basic type is a scalar type, as described in this section. It includes
-integers, GNU/C bitfields, enumerations, and floating point values.
-
-4.1.1 Type inheritance
-
-Type specifications can be inherited to allow deriving types from a
-type class. For example, see the uint32_t named type derived from the "integer"
-type class below ("Integers" section). Types have a precise binary
-representation in the trace. A type class has methods to read and write these
-types, but must be derived into a type to be usable in an event field.
-
-4.1.2 Alignment
-
-We define "byte-packed" types as aligned on the byte size, namely 8-bit.
-We define "bit-packed" types as following on the next bit, as defined by the
-"Integers" section.
-
-Each basic type must specify its alignment, in bits. Examples of
-possible alignments are: bit-packed (align = 1), byte-packed (align =
-8), or word-aligned (e.g. align = 32 or align = 64). The choice depends
-on the architecture preference and compactness vs performance trade-offs
-of the implementation.  Architectures providing fast unaligned write
-byte-packed basic types to save space, aligning each type on byte
-boundaries (8-bit). Architectures with slow unaligned writes align types
-on specific alignment values. If no specific alignment is declared for a
-type, it is assumed to be bit-packed for integers with size not multiple
-of 8 bits and for gcc bitfields. All other basic types are byte-packed
-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.
-
-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
-
-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 */
-
-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
-multiplied by CHAR_BIT.
-We require the size of "char" and "unsigned char" types (CHAR_BIT) to be fixed
-to 8 bits for cross-endianness compatibility.
-
-TSDL meta-data representation:
-
-  size = value;    (value is in bits)
-
-4.1.5 Integers
-
-Signed integers are represented in two-complement. Integer alignment,
-size, signedness and byte ordering are defined in the TSDL meta-data.
-Integers aligned on byte size (8-bit) and with length multiple of byte
-size (8-bit) correspond to the C99 standard integers. In addition,
-integers with alignment and/or size that are _not_ a multiple of the
-byte size are permitted; these correspond to the C99 standard bitfields,
-with the added specification that the CTF integer bitfields have a fixed
-binary representation. Integer size needs to be a positive integer.
-Integers of size 0 are forbidden. A MIT-licensed reference
-implementation of the CTF portable bitfields is available at:
-
-  http://git.efficios.com/?p=babeltrace.git;a=blob;f=include/babeltrace/bitfield.h
-
-Binary representation of integers:
-
-- On little and big endian:
-  - Within a byte, high bits correspond to an integer high bits, and low bits
-    correspond to low bits.
-- On little endian:
-  - Integer across multiple bytes are placed from the less significant to the
-    most significant.
-  - Consecutive integers are placed from lower bits to higher bits (even within
-    a byte).
-- On big endian:
-  - Integer across multiple bytes are placed from the most significant to the
-    less significant.
-  - Consecutive integers are placed from higher bits to lower bits (even within
-    a byte).
-
-This binary representation is derived from the bitfield implementation in GCC
-for little and big endian. However, contrary to what GCC does, integers can
-cross units boundaries (no padding is required). Padding can be explicitly
-added (see 4.1.6 GNU/C bitfields) to follow the GCC layout if needed.
-
-TSDL meta-data representation:
-
-  integer {
-    signed = true OR false;                     /* default false */
-    byte_order = native OR network OR be OR le; /* default native */
-    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 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;
-  }
-
-Example of type inheritance (creation of a uint32_t named type):
-
-typealias integer {
-  size = 32;
-  signed = false;
-  align = 32;
-} := uint32_t;
-
-Definition of a named 5-bit signed bitfield:
-
-typealias integer {
-  size = 5;
-  signed = true;
-  align = 1;
-} := int5_t;
-
-The character encoding field can be used to specify that the integer
-must be printed as a text character when read. e.g.:
-
-typealias integer {
-  size = 8;
-  align = 8;
-  signed = false;
-  encoding = UTF8;
-} := utf_char;
-
-
-4.1.6 GNU/C bitfields
-
-The GNU/C bitfields follow closely the integer representation, with a
-particularity on alignment: if a bitfield cannot fit in the current unit, the
-unit is padded and the bitfield starts at the following unit. The unit size is
-defined by the size of the type "unit_type".
-
-TSDL meta-data representation:
-
-  unit_type name:size;
-
-As an example, the following structure declared in C compiled by GCC:
-
-struct example {
-  short a:12;
-  short b:5;
-};
-
-The example structure is aligned on the largest element (short). The second
-bitfield would be aligned on the next unit boundary, because it would not fit in
-the current unit.
-
-4.1.7 Floating point
-
-The floating point values byte ordering is defined in the TSDL meta-data.
-
-Floating point values follow the IEEE 754-2008 standard interchange formats.
-Description of the floating point values include the exponent and mantissa size
-in bits. Some requirements are imposed on the floating point values:
-
-- FLT_RADIX must be 2.
-- mant_dig is the number of digits represented in the mantissa. It is specified
-  by the ISO C99 standard, section 5.2.4, as FLT_MANT_DIG, DBL_MANT_DIG and
-  LDBL_MANT_DIG as defined by <float.h>.
-- exp_dig is the number of digits represented in the exponent. Given that
-  mant_dig is one bit more than its actual size in bits (leading 1 is not
-  needed) and also given that the sign bit always takes one bit, exp_dig can be
-  specified as:
-
-  - sizeof(float) * CHAR_BIT - FLT_MANT_DIG
-  - sizeof(double) * CHAR_BIT - DBL_MANT_DIG
-  - sizeof(long double) * CHAR_BIT - LDBL_MANT_DIG
-
-TSDL meta-data representation:
-
-floating_point {
-  exp_dig = value;
-  mant_dig = value;
-  byte_order = native OR network OR be OR le;
-  align = value;
-}
-
-Example of type inheritance:
-
-typealias floating_point {
-  exp_dig = 8;         /* sizeof(float) * CHAR_BIT - FLT_MANT_DIG */
-  mant_dig = 24;       /* FLT_MANT_DIG */
-  byte_order = native;
-  align = 32;
-} := float;
-
-TODO: define NaN, +inf, -inf behavior.
-
-Bit-packed, byte-packed or larger alignments can be used for floating
-point values, similarly to integers.
-
-4.1.8 Enumerations
-
-Enumerations are a mapping between an integer type and a table of strings. The
-numerical representation of the enumeration follows the integer type specified
-by the meta-data. The enumeration mapping table is detailed in the enumeration
-description within the meta-data. The mapping table maps inclusive value
-ranges (or single values) to strings. Instead of being limited to simple
-"value -> string" mappings, these enumerations map
-"[ start_value ... end_value ] -> string", which map inclusive ranges of
-values to strings.  An enumeration from the C language can be represented in
-this format by having the same start_value and end_value for each
-mapping, which is in fact a range of size 1. This single-value range is
-supported without repeating the start and end values with the value =
-string declaration.  Enumerations need to contain at least one entry.
-
-enum name : integer_type {
-  somestring          = start_value1 ... end_value1,
-  "other string"      = start_value2 ... end_value2,
-  yet_another_string,	/* will be assigned to end_value2 + 1 */
-  "some other string" = value,
-  ...
-};
-
-If the values are omitted, the enumeration starts at 0 and increment of 1 for
-each entry. An entry with omitted value that follows a range entry takes
-as value the end_value of the previous range + 1:
-
-enum name : unsigned int {
-  ZERO,
-  ONE,
-  TWO,
-  TEN = 10,
-  ELEVEN,
-};
-
-Overlapping ranges within a single enumeration are implementation defined.
-
-A nameless enumeration can be declared as a field type or as part of a typedef:
-
-enum : integer_type {
-  ...
-}
-
-Enumerations omitting the container type ": integer_type" use the "int"
-type (for compatibility with C99). The "int" type must be previously
-declared. E.g.:
-
-typealias integer { size = 32; align = 32; signed = true; } := int;
-
-enum {
-  ...
-}
-
-
-4.2 Compound types
-
-Compound are aggregation of type declarations. Compound types include
-structures, variant, arrays, sequences, and strings.
-
-4.2.1 Structures
-
-Structures are aligned on the largest alignment required by basic types
-contained within the structure. (This follows the ISO/C standard for structures)
-
-TSDL meta-data representation of a named structure:
-
-struct name {
-  field_type field_name;
-  field_type field_name;
-  ...
-}; 
-
-Example:
-
-struct example {
-  integer {                       /* Nameless type */
-    size = 16;
-    signed = true;
-    align = 16;
-  } first_field_name;
-  uint64_t second_field_name;  /* Named type declared in the meta-data */
-};
-
-The fields are placed in a sequence next to each other. They each
-possess a field name, which is a unique identifier within the structure.
-The identifier is not allowed to use any reserved keyword
-(see Section C.1.2). Replacing reserved keywords with
-underscore-prefixed field names is recommended. Fields starting with an
-underscore should have their leading underscore removed by the CTF trace
-readers.
-
-A nameless structure can be declared as a field type or as part of a typedef:
-
-struct {
-  ...
-}
-
-Alignment for a structure compound type can be forced to a minimum value
-by adding an "align" specifier after the declaration of a structure
-body. This attribute is read as: align(value). The value is specified in
-bits. The structure will be aligned on the maximum value between this
-attribute and the alignment required by the basic types contained within
-the structure. e.g.
-
-struct {
-  ...
-} align(32)
-
-4.2.2 Variants (Discriminated/Tagged Unions)
-
-A CTF variant is a selection between different types. A CTF variant must
-always be defined within the scope of a structure or within fields
-contained within a structure (defined recursively). A "tag" enumeration
-field must appear in either the same static scope, prior to the variant
-field (in field declaration order), in an upper static scope, or in an
-upper dynamic scope (see Section 7.3.2). The type selection is indicated
-by the mapping from the enumeration value to the string used as variant
-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. It is not
-required that each enumeration mapping appears as variant type tag
-field. It is also not required that each variant type tag appears as
-enumeration mapping. However, it is required that any enumeration
-mapping encountered within a stream has a matching variant type tag
-field.
-
-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
-reserved keyword (see Section C.1.2). Replacing reserved keywords with
-underscore-prefixed field names is recommended. Fields starting with an
-underscore should have their leading underscore removed by the CTF trace
-readers.
-
-
-A named variant declaration followed by its definition within a structure
-declaration:
-
-variant name {
-  field_type sel1;
-  field_type sel2;
-  field_type sel3;
-  ...
-};
-
-struct {
-  enum : integer_type { sel1, sel2, sel3, ... } tag_field;
-  ...
-  variant name <tag_field> v;
-}
-
-An unnamed variant definition within a structure is expressed by the following
-TSDL meta-data:
-
-struct {
-  enum : integer_type { sel1, sel2, sel3, ... } tag_field;
-  ...
-  variant <tag_field> {
-    field_type sel1;
-    field_type sel2;
-    field_type sel3;
-    ...
-  } v;
-}
-
-Example of a named variant within a sequence that refers to a single tag field:
-
-variant example {
-  uint32_t a;
-  uint64_t b;
-  short c;
-};
-
-struct {
-  enum : uint2_t { a, b, c } choice;
-  unsigned int seqlen;
-  variant example <choice> v[seqlen];
-}
-
-Example of an unnamed variant:
-
-struct {
-  enum : uint2_t { a, b, c, d } choice;
-  /* Unrelated fields can be added between the variant and its tag */
-  int32_t somevalue;
-  variant <choice> {
-    uint32_t a;
-    uint64_t b;
-    short c;
-    struct {
-      unsigned int field1;
-      uint64_t field2;
-    } d;
-  } s;
-}
-
-Example of an unnamed variant within an array:
-
-struct {
-  enum : uint2_t { a, b, c } choice;
-  variant <choice> {
-    uint32_t a;
-    uint64_t b;
-    short c;
-  } v[10];
-}
-
-Example of a variant type definition within a structure, where the defined type
-is then declared within an array of structures. This variant refers to a tag
-located in an upper static scope. This example clearly shows that a variant
-type definition referring to the tag "x" uses the closest preceding field from
-the static scope of the type definition.
-
-struct {
-  enum : uint2_t { a, b, c, d } x;
-
-  typedef variant <x> {	/*
-			 * "x" refers to the preceding "x" enumeration in the
-			 * static scope of the type definition.
-			 */
-    uint32_t a;
-    uint64_t b;
-    short c;
-  } example_variant;
-
-  struct {
-    enum : int { x, y, z } x;	/* This enumeration is not used by "v". */
-    example_variant v; 		/*
-				 * "v" uses the "enum : uint2_t { a, b, c, d }"
-				 * tag.
-				 */
-  } a[10];
-}
-
-4.2.3 Arrays
-
-Arrays are fixed-length. Their length is declared in the type
-declaration within the meta-data. They contain an array of "inner type"
-elements, which can refer to any type not containing the type of the
-array being declared (no circular dependency). The length is the number
-of elements in an array.
-
-TSDL meta-data representation of a named array:
-
-typedef elem_type name[length];
-
-A nameless array can be declared as a field type within a structure, e.g.:
-
-  uint8_t field_name[10];
-
-Arrays are always aligned on their element alignment requirement.
-
-4.2.4 Sequences
-
-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
-length field represents the number of elements in the sequence. The
-sequence per se is an array of "inner type" elements.
-
-TSDL meta-data representation for a sequence type definition:
-
-struct {
-  unsigned int length_field;
-  typedef elem_type typename[length_field];
-  typename seq_field_name;
-}
-
-A sequence can also be declared as a field type, e.g.:
-
-struct {
-  unsigned int length_field;
-  long seq_field_name[length_field];
-}
-
-Multiple sequences can refer to the same length field, and these length
-fields can be in a different upper dynamic scope:
-
-e.g., assuming the stream.event.header defines:
-
-stream {
-  ...
-  id = 1;
-  event.header := struct {
-    uint16_t seq_len;
-  };
-};
-
-event {
-  ...
-  stream_id = 1;
-  fields := struct {
-    long seq_a[stream.event.header.seq_len];
-    char seq_b[stream.event.header.seq_len];
-  };
-};
-
-The sequence elements follow the "array" specifications.
-
-4.2.5 Strings
-
-Strings are an array of bytes of variable size and are terminated by a '\0'
-"NULL" character.  Their encoding is described in the TSDL meta-data. In
-absence of encoding attribute information, the default encoding is
-UTF-8.
-
-TSDL meta-data representation of a named string type:
-
-typealias string {
-  encoding = UTF8 OR ASCII;
-} := name;
-
-A nameless string type can be declared as a field type:
-
-string field_name;	/* Use default UTF8 encoding */
-
-Strings are always aligned on byte size.
-
-5. Event Packet Header
-
-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.
-
-Event packet header (all fields are optional, specified by TSDL meta-data):
-
-- Magic number (CTF magic number: 0xC1FC1FC1) specifies that this is a
-  CTF packet. This magic number is optional, but when present, it should
-  come at the very beginning of the packet.
-- Trace UUID, used to ensure the event packet match the meta-data used.
-  (note: we cannot use a meta-data checksum in every cases instead of a
-   UUID because meta-data can be appended to while tracing is active)
-  This field is optional.
-- Stream ID, used as reference to stream description in meta-data.
-  This field is optional if there is only one stream description in the
-  meta-data, but becomes required if there are more than one stream in
-  the TSDL meta-data description.
-
-Event packet context (all fields are optional, specified by TSDL meta-data):
-
-- Event packet content size (in bits).
-- Event packet size (in bits, includes padding).
-- Event packet content checksum. Checksum excludes the event packet
-  header.
-- Per-stream event packet sequence count (to deal with UDP packet loss). The
-  number of significant sequence counter bits should also be present, so
-  wrap-arounds are dealt with correctly.
-- Time-stamp at the beginning and time-stamp at the end of the event packet.
-  Both timestamps are written in the packet header, but sampled respectively
-  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
-    the last event in the event packet.
-    * Note: producer-consumer buffer full condition can fill the current
-            event packet with padding so we know exactly where events have been
-	    discarded. However, if the buffer full condition chooses not
-	    to fill the current event packet with padding, all we know
-	    about the timestamp range in which the events have been
-	    discarded is that it is somewhere between the beginning and
-            the end of the packet.
-- Lossless compression scheme used for the event packet content. Applied
-  directly to raw data. New types of compression can be added in following
-  versions of the format.
-  0: no compression scheme
-  1: bzip2
-  2: gzip
-  3: xz
-- Cypher used for the event packet content. Applied after compression.
-  0: no encryption
-  1: AES
-- Checksum scheme used for the event packet content. Applied after encryption.
-  0: no checksum
-  1: md5
-  2: sha1
-  3: crc32
-
-5.1 Event Packet Header Description
-
-The event packet header layout is indicated by the trace packet.header
-field. Here is a recommended structure type for the packet header with
-the fields typically expected (although these fields are each optional):
-
-struct event_packet_header {
-  uint32_t magic;
-  uint8_t  uuid[16];
-  uint32_t stream_id;
-};
-
-trace {
-  ...
-  packet.header := struct event_packet_header;
-};
-
-If the magic number is not present, tools such as "file" will have no
-mean to discover the file type.
-
-If the uuid is not present, no validation that the meta-data actually
-corresponds to the stream is performed.
-
-If the stream_id packet header field is missing, the trace can only
-contain a single stream. Its "id" field can be left out, and its events
-don't need to declare a "stream_id" field.
-
-
-5.2 Event Packet Context Description
-
-Event packet context example. These are declared within the stream declaration
-in the meta-data. All these fields are optional. If the packet size field is
-missing, the whole stream only contains a single packet. If the content
-size field is missing, the packet is filled (no padding). The content
-and packet sizes include all headers.
-
-An example event packet context type:
-
-struct event_packet_context {
-  uint64_t timestamp_begin;
-  uint64_t timestamp_end;
-  uint32_t checksum;
-  uint32_t stream_packet_count;
-  uint32_t events_discarded;
-  uint32_t cpu_id;
-  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;
-};
-
-
-6. Event Structure
-
-The overall structure of an event is:
-
-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.
-
-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
-example, two types of events headers. Type 1 accommodates streams with less than
-31 event IDs. Type 2 accommodates streams with 31 or more event IDs.
-
-One major factor can vary between streams: the number of event IDs assigned to
-a stream. Luckily, this information tends to stay relatively constant (modulo
-event registration while trace is being recorded), so we can specify different
-representations for streams containing few event IDs and streams containing
-many event IDs, so we end up representing the event ID and time-stamp as
-densely as possible in each case.
-
-The header is extended in the rare occasions where the information cannot be
-represented in the ranges available in the standard event header. They are also
-used in the rare occasions where the data required for a field could not be
-collected: the flag corresponding to the missing field within the missing_fields
-array is then set to 1.
-
-Types uintX_t represent an X-bit unsigned integer, as declared with
-either:
-
-  typealias integer { size = X; align = X; signed = false; } := uintX_t;
-
-    or
-
-  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
-
-  - Aligned on 32-bit (or 8-bit if byte-packed, depending on the architecture
-    preference).
-  - Native architecture byte ordering.
-  - For "compact" selection
-    - Fixed size: 32 bits.
-  - For "extended" selection
-    - Size depends on the architecture and variant alignment.
-
-struct event_header_1 {
-  /*
-   * id: range: 0 - 30.
-   * id 31 is reserved to indicate an extended header.
-   */
-  enum : uint5_t { compact = 0 ... 30, extended = 31 } id;
-  variant <id> {
-    struct {
-      uint27_t timestamp;
-    } compact;
-    struct {
-      uint32_t id;			 /* 32-bit event IDs */
-      uint64_t timestamp;		 /* 64-bit timestamps */
-    } extended;
-  } v;
-} align(32);	/* or align(8) */
-
-
-6.1.2 Type 2 - Many event IDs
-
-  - Aligned on 16-bit (or 8-bit if byte-packed, depending on the architecture
-    preference).
-  - Native architecture byte ordering.
-  - For "compact" selection
-    - Size depends on the architecture and variant alignment.
-  - For "extended" selection
-    - Size depends on the architecture and variant alignment.
-
-struct event_header_2 {
-  /*
-   * id: range: 0 - 65534.
-   * id 65535 is reserved to indicate an extended header.
-   */
-  enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;
-  variant <id> {
-    struct {
-      uint32_t timestamp;
-    } compact;
-    struct {
-      uint32_t id;			 /* 32-bit event IDs */
-      uint64_t timestamp;		 /* 64-bit timestamps */ 
-    } extended;
-  } v;
-} align(16);	/* or align(8) */
-
-
-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
-stream and event meta-data descriptions. The stream context is applied
-to all events within the stream. The stream context structure follows
-the event header. The event context is applied to specific events. Its
-structure follows the stream context structure.
-
-An example of stream-level event context is to save the event payload size with
-each event, or to save the current PID with each event.  These are declared
-within the stream declaration within the meta-data:
-
-  stream {
-    ...
-    event.context := struct {
-        uint pid;
-        uint16_t payload_size;
-    };
-  };
-
-An example of event-specific event context is to declare a bitmap of missing
-fields, only appended after the stream event context if the extended event
-header is selected. NR_FIELDS is the number of fields within the event (a
-numeric value).
-
-  event {
-    context := struct {
-      variant <id> {
-        struct { } compact;
-        struct {
-          uint1_t missing_fields[NR_FIELDS]; /* missing event fields bitmap */
-        } extended;
-      } v;
-    };
-    ...
-  }
-
-6.3 Event Payload
-
-An event payload contains fields specific to a given event type. The fields
-belonging to an event type are described in the event-specific meta-data
-within a structure type.
-
-6.3.1 Padding
-
-No padding at the end of the event payload. This differs from the ISO/C standard
-for structures, but follows the CTF standard for structures. In a trace, even
-though it makes sense to align the beginning of a structure, it really makes no
-sense to add padding at the end of the structure, because structures are usually
-not followed by a structure of the same type.
-
-This trick can be done by adding a zero-length "end" field at the end of the C
-structures, and by using the offset of this field rather than using sizeof()
-when calculating the size of a structure (see Appendix "A. Helper macros").
-
-6.3.2 Alignment
-
-The event payload is aligned on the largest alignment required by types
-contained within the payload. (This follows the ISO/C standard for structures)
-
-
-7. Trace Stream Description Language (TSDL)
-
-The Trace Stream Description Language (TSDL) allows expression of the
-binary trace streams layout in a C99-like Domain Specific Language
-(DSL).
-
-
-7.1 Meta-data
-
-The trace stream layout description is located in the trace meta-data.
-The meta-data is itself located in a stream identified by its name:
-"metadata".
-
-The meta-data description can be expressed in two different formats:
-text-only and packet-based. The text-only description facilitates
-generation of meta-data and provides a convenient way to enter the
-meta-data information by hand. The packet-based meta-data provides the
-CTF stream packet facilities (checksumming, compression, encryption,
-network-readiness) for meta-data stream generated and transported by a
-tracer.
-
-The text-only meta-data file is a plain-text TSDL description. This file
-must begin with the following characters to identify the file as a CTF
-TSDL text-based metadata file (without the double-quotes) :
-
-"/* CTF"
-
-It must be followed by a space, and the version of the specification
-followed by the CTF trace, e.g.:
-
-" 1.8"
-
-These characters allow automated discovery of file type and CTF
-specification version. They are interpreted as a the beginning of a
-comment by the TSDL metadata parser.  The comment can be continued to
-contain extra commented characters before it is closed.
-
-The packet-based meta-data is made of "meta-data packets", which each
-start with a meta-data packet header. The packet-based meta-data
-description is detected by reading the magic number "0x75D11D57" at the
-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
-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 */
-  uint8_t  uuid[16];			/* Unique Universal Identifier */
-  uint32_t checksum;			/* 0 if unused */
-  uint32_t content_size;		/* in bits */
-  uint32_t packet_size;			/* in bits */
-  uint8_t  compression_scheme;		/* 0 if unused */
-  uint8_t  encryption_scheme;		/* 0 if unused */
-  uint8_t  checksum_scheme;		/* 0 if unused */
-  uint8_t  major;			/* CTF spec version major number */
-  uint8_t  minor;			/* CTF spec version minor number */
-};
-
-The packet-based meta-data can be converted to a text-only meta-data by
-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
-treated as comments.  Boolean values can be represented as true, TRUE,
-or 1 for true, and false, FALSE, or 0 for false. Within the string-based
-meta-data description, the trace UUID is represented as a string of
-hexadecimal digits and dashes "-". In the event packet header, the trace
-UUID is represented as an array of bytes.
-
-
-7.2 Declaration vs Definition
-
-A declaration associates a layout to a type, without specifying where
-this type is located in the event structure hierarchy (see Section 6).
-This therefore includes typedef, typealias, as well as all type
-specifiers. In certain circumstances (typedef, structure field and
-variant field), a declaration is followed by a declarator, which specify
-the newly defined type name (for typedef), or the field name (for
-declarations located within structure and variants). Array and sequence,
-declared with square brackets ("[" "]"), are part of the declarator,
-similarly to C99. The enumeration base type is specified by
-": enum_base", which is part of the type specifier. The variant tag
-name, specified between "<" ">", is also part of the type specifier.
-
-A definition associates a type to a location in the event structure
-hierarchy (see Section 6). This association is denoted by ":=", as shown
-in Section 7.3.
-
-
-7.3 TSDL Scopes
-
-TSDL uses three different types of scoping: a lexical scope is used for
-declarations and type definitions, and static and dynamic scopes are
-used for variants references to tag fields (with relative and absolute
-path lookups) and for sequence references to length fields.
-
-7.3.1 Lexical Scope
-
-Each of "trace", "env", "stream", "event", "struct" and "variant" have
-their own nestable declaration scope, within which types can be declared
-using "typedef" and "typealias". A root declaration scope also contains
-all declarations located outside of any of the aforementioned
-declarations. An inner declaration scope can refer to type declared
-within its container lexical scope prior to the inner declaration scope.
-Redefinition of a typedef or typealias is not valid, although hiding an
-upper scope typedef or typealias is allowed within a sub-scope.
-
-7.3.2 Static and Dynamic Scopes
-
-A local static scope consists in the scope generated by the declaration
-of fields within a compound type. A static scope is a local static scope
-augmented with the nested sub-static-scopes it contains.
-
-A dynamic scope consists in the static scope augmented with the
-implicit event structure definition hierarchy presented at Section 6.
-
-Multiple declarations of the same field name within a local static scope
-is not valid. It is however valid to re-use the same field name in
-different local scopes.
-
-Nested static and dynamic scopes form lookup paths. These are used for
-variant tag and sequence length references. They are used at the variant
-and sequence definition site to look up the location of the tag field
-associated with a variant, and to lookup up the location of the length
-field associated with a sequence.
-
-Variants and sequences can refer to a tag field either using a relative
-path or an absolute path. The relative path is relative to the scope in
-which the variant or sequence performing the lookup is located.
-Relative paths are only allowed to lookup within the same static scope,
-which includes its nested static scopes. Lookups targeting parent static
-scopes need to be performed with an absolute path.
-
-Absolute path lookups use the full path including the dynamic scope
-followed by a "." and then the static scope. Therefore, variants (or
-sequences) in lower levels in the dynamic scope (e.g. event context) can
-refer to a tag (or length) field located in upper levels (e.g. in the
-event header) by specifying, in this case, the associated tag with
-<stream.event.header.field_name>. This allows, for instance, the event
-context to define a variant referring to the "id" field of the event
-header as selector.
-
-The dynamic scope prefixes are thus:
-
- - Trace Environment: <env. >,
- - Trace Packet Header: <trace.packet.header. >,
- - Stream Packet Context: <stream.packet.context. >,
- - Event Header: <stream.event.header. >,
- - Stream Event Context: <stream.event.context. >,
- - Event Context: <event.context. >,
- - Event Payload: <event.fields. >.
-
-
-The target dynamic scope must be specified explicitly when referring to
-a field outside of the static scope (absolute scope reference). No
-conflict can occur between relative and dynamic paths, because the
-keywords "trace", "stream", and "event" are reserved, and thus
-not permitted as field names. It is recommended that field names
-clashing with CTF and C99 reserved keywords use an underscore prefix to
-eliminate the risk of generating a description containing an invalid
-field name. Consequently, fields starting with an underscore should have
-their leading underscore removed by the CTF trace readers.
-
-
-The information available in the dynamic scopes can be thought of as the
-current tracing context. At trace production, information about the
-current context is saved into the specified scope field levels. At trace
-consumption, for each event, the current trace context is therefore
-readable by accessing the upper dynamic scopes.
-
-
-7.4 TSDL Examples
-
-The grammar representing the TSDL meta-data is presented in Appendix C.
-TSDL Grammar. This section presents a rather lighter reading that
-consists in examples of TSDL meta-data, with template values.
-
-The stream "id" can be left out if there is only one stream in the
-trace. The event "id" field can be left out if there is only one event
-in a stream.
-
-trace {
-  major = value;			/* CTF spec version major number */
-  minor = value;			/* CTF spec version minor number */
-  uuid = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa";	/* Trace UUID */
-  byte_order = be OR le;			/* Endianness (required) */
-  packet.header := struct {
-    uint32_t magic;
-    uint8_t  uuid[16];
-    uint32_t stream_id;
-  };
-};
-
-/*
- * The "env" (environment) scope contains assignment expressions. The
- * field names and content are implementation-defined.
- */
-env {
-  pid = value;			/* example */
-  proc_name = "name";		/* example */
-  ...
-};
-
-stream {
-  id = stream_id;
-  /* Type 1 - Few event IDs; Type 2 - Many event IDs. See section 6.1. */
-  event.header := event_header_1 OR event_header_2;
-  event.context := struct {
-    ...
-  };
-  packet.context := struct {
-    ...
-  };
-};
-
-event {
-  name = "event_name";
-  id = value;			/* Numeric identifier within the stream */
-  stream_id = stream_id;
-  loglevel = value;
-  model.emf.uri = "string";
-  context := struct {
-    ...
-  };
-  fields := struct {
-    ...
-  };
-};
-
-callsite {
-  name = "event_name";
-  func = "func_name";
-  file = "myfile.c";
-  line = 39;
-  ip = 0x40096c;
-};
-
-/* More detail on types in section 4. Types */
-
-/*
- * Named types:
- *
- * Type declarations behave similarly to the C standard.
- */
-
-typedef aliased_type_specifiers new_type_declarators;
-
-/* e.g.: typedef struct example new_type_name[10]; */
-
-/*
- * typealias
- *
- * The "typealias" declaration can be used to give a name (including
- * pointer declarator specifier) to a type. It should also be used to
- * map basic C types (float, int, unsigned long, ...) to a CTF type.
- * Typealias is a superset of "typedef": it also allows assignment of a
- * simple variable identifier to a type.
- */
-
-typealias type_class {
-  ...
-} := type_specifiers type_declarator;
-
-/*
- * e.g.: 
- * typealias integer {
- *   size = 32;
- *   align = 32;
- *   signed = false;
- * } := struct page *;
- *
- * typealias integer {
- *  size = 32;
- *  align = 32;
- *  signed = true;
- * } := int;
- */
-
-struct name {
-  ...
-};
-
-variant name {
-  ...
-};
-
-enum name : integer_type {
-  ...
-};
-
-
-/*
- * Unnamed types, contained within compound type fields, typedef or typealias.
- */
-
-struct {
-  ...
-}
-
-struct {
-  ...
-} align(value)
-
-variant {
-  ...
-}
-
-enum : integer_type {
-  ...
-}
-
-typedef type new_type[length];
-
-struct {
-  type field_name[length];
-}
-
-typedef type new_type[length_type];
-
-struct {
-  type field_name[length_type];
-}
-
-integer {
-  ...
-}
-
-floating_point {
-  ...
-}
-
-struct {
-  integer_type field_name:size;		/* GNU/C bitfield */
-}
-
-struct {
-  string field_name;
-}
-
-
-8. Clocks
-
-Clock metadata allows to describe the clock topology of the system, as
-well as to detail each clock parameter. In absence of clock description,
-it is assumed that all fields named "timestamp" use the same clock
-source, which increments once per nanosecond.
-
-Describing a clock and how it is used by streams is threefold: first,
-the clock and clock topology should be described in a "clock"
-description block, e.g.:
-
-clock {
-	name = cycle_counter_sync;
-	uuid = "62189bee-96dc-11e0-91a8-cfa3d89f3923";
-	description = "Cycle counter synchronized across CPUs";
-	freq = 1000000000;	       /* frequency, in Hz */
-	/* precision in seconds is: 1000 * (1/freq) */
-	precision = 1000;
-	/*
-	 * clock value offset from Epoch is:
-	 * offset_s + (offset * (1/freq))
-	 */
-	offset_s = 1326476837;
-	offset = 897235420;
-	absolute = FALSE;
-};
-
-The mandatory "name" field specifies the name of the clock identifier,
-which can later be used as a reference. The optional field "uuid" is the
-unique identifier of the clock. It can be used to correlate different
-traces that use the same clock. An optional textual description string
-can be added with the "description" field. The "freq" field is the
-initial frequency of the clock, in Hz. If the "freq" field is not
-present, the frequency is assumed to be 1000000000 (providing clock
-increment of 1 ns). The optional "precision" field details the
-uncertainty on the clock measurements, in (1/freq) units. The "offset_s"
-and "offset" fields indicate the offset from POSIX.1 Epoch, 1970-01-01
-00:00:00 +0000 (UTC), to the zero of value of the clock. The "offset_s"
-field is in seconds. The "offset" field is in (1/freq) units. If any of
-the "offset_s" or "offset" field is not present, it is assigned the 0
-value. The field "absolute" is TRUE if the clock is a global reference
-across different clock uuid (e.g. NTP time). Otherwise, "absolute" is
-FALSE, and the clock can be considered as synchronized only with other
-clocks that have the same uuid.
-
-
-Secondly, a reference to this clock should be added within an integer
-type:
-
-typealias integer {
-	size = 64; align = 1; signed = false;
-	map = clock.cycle_counter_sync.value;
-} := uint64_ccnt_t;
-
-Thirdly, stream declarations can reference the clock they use as a
-time-stamp source:
-
-struct packet_context {
-	uint64_ccnt_t ccnt_begin;
-	uint64_ccnt_t ccnt_end;
-	/* ... */
-};
-
-stream {
-	/* ... */
-	event.header := struct {
-		uint64_ccnt_t timestamp;
-		/* ... */
-	};
-	packet.context := struct packet_context;
-};
-
-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 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,
-the beginning and the end of each packet.
-
-
-A. Helper macros
-
-The two following macros keep track of the size of a GNU/C structure without
-padding at the end by placing HEADER_END as the last field. A one byte end field
-is used for C90 compatibility (C99 flexible arrays could be used here). Note
-that this does not affect the effective structure size, which should always be
-calculated with the header_sizeof() helper.
-
-#define HEADER_END		char end_field
-#define header_sizeof(type)	offsetof(typeof(type), end_field)
-
-
-B. Stream Header Rationale
-
-An event stream is divided in contiguous event packets of variable size. These
-subdivisions allow the trace analyzer to perform a fast binary search by time
-within the stream (typically requiring to index only the event packet headers)
-without reading the whole stream. These subdivisions have a variable size to
-eliminate the need to transfer the event packet padding when partially filled
-event packets must be sent when streaming a trace for live viewing/analysis.
-An event packet can contain a certain amount of padding at the end. Dividing
-streams into event packets is also useful for network streaming over UDP and
-flight recorder mode tracing (a whole event packet can be swapped out of the
-buffer atomically for reading).
-
-The stream header is repeated at the beginning of each event packet to allow
-flexibility in terms of:
-
-  - streaming support,
-  - allowing arbitrary buffers to be discarded without making the trace
-    unreadable,
-  - allow UDP packet loss handling by either dealing with missing event packet
-    or asking for re-transmission.
-  - transparently support flight recorder mode,
-  - transparently support crash dump.
-
-
-C. TSDL Grammar
-
-/*
- * Common Trace Format (CTF) Trace Stream Description Language (TSDL) Grammar.
- *
- * Inspired from the C99 grammar:
- * http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf (Annex A)
- * and c++1x grammar (draft)
- * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3291.pdf (Annex A)
- *
- * Specialized for CTF needs by including only constant and declarations from
- * C99 (excluding function declarations), and by adding support for variants,
- * sequences and CTF-specific specifiers. Enumeration container types
- * semantic is inspired from c++1x enum-base.
- */
-
-1) Lexical grammar
-
-1.1) Lexical elements
-
-token:
-	keyword
-	identifier
-	constant
-	string-literal
-	punctuator
-
-1.2) Keywords
-
-keyword: is one of
-
-align
-callsite
-const
-char
-clock
-double
-enum
-env
-event
-floating_point
-float
-integer
-int
-long
-short
-signed
-stream
-string
-struct
-trace
-typealias
-typedef
-unsigned
-variant
-void
-_Bool
-_Complex
-_Imaginary
-
-
-1.3) Identifiers
-
-identifier:
-	identifier-nondigit
-	identifier identifier-nondigit
-	identifier digit
-
-identifier-nondigit:
-	nondigit
-	universal-character-name
-	any other implementation-defined characters
-
-nondigit:
-	_
-	[a-zA-Z]	/* regular expression */
-
-digit:
-	[0-9]		/* regular expression */
-
-1.4) Universal character names
-
-universal-character-name:
-	\u hex-quad
-	\U hex-quad hex-quad
-
-hex-quad:
-	hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit
-
-1.5) Constants
-
-constant:
-	integer-constant
-	enumeration-constant
-	character-constant
-
-integer-constant:
-	decimal-constant integer-suffix-opt
-	octal-constant integer-suffix-opt
-	hexadecimal-constant integer-suffix-opt
-
-decimal-constant:
-	nonzero-digit
-	decimal-constant digit
-
-octal-constant:
-	0
-	octal-constant octal-digit
-
-hexadecimal-constant:
-	hexadecimal-prefix hexadecimal-digit
-	hexadecimal-constant hexadecimal-digit
-
-hexadecimal-prefix:
-	0x
-	0X
-
-nonzero-digit:
-	[1-9]
-
-integer-suffix:
-	unsigned-suffix long-suffix-opt
-	unsigned-suffix long-long-suffix
-	long-suffix unsigned-suffix-opt
-	long-long-suffix unsigned-suffix-opt
-
-unsigned-suffix:
-	u
-	U
-
-long-suffix:
-	l
-	L
-
-long-long-suffix:
-	ll
-	LL
-
-enumeration-constant:
-	identifier
-	string-literal
-
-character-constant:
-	' c-char-sequence '
-	L' c-char-sequence '
-
-c-char-sequence:
-	c-char
-	c-char-sequence c-char
-
-c-char:
-	any member of source charset except single-quote ('), backslash
-	(\), or new-line character.
-	escape-sequence
-
-escape-sequence:
-	simple-escape-sequence
-	octal-escape-sequence
-	hexadecimal-escape-sequence
-	universal-character-name
-
-simple-escape-sequence: one of
-	\' \" \? \\ \a \b \f \n \r \t \v
-
-octal-escape-sequence:
-	\ octal-digit
-	\ octal-digit octal-digit
-	\ octal-digit octal-digit octal-digit
-
-hexadecimal-escape-sequence:
-	\x hexadecimal-digit
-	hexadecimal-escape-sequence hexadecimal-digit
-
-1.6) String literals
-
-string-literal:
-	" s-char-sequence-opt "
-	L" s-char-sequence-opt "
-
-s-char-sequence:
-	s-char
-	s-char-sequence s-char
-
-s-char:
-	any member of source charset except double-quote ("), backslash
-	(\), or new-line character.
-	escape-sequence
-
-1.7) Punctuators
-
-punctuator: one of
-	[ ] ( ) { } . -> * + - < > : ; ... = ,
-
-
-2) Phrase structure grammar
-
-primary-expression:
-	identifier
-	constant
-	string-literal
-	( unary-expression )
-
-postfix-expression:
-	primary-expression
-	postfix-expression [ unary-expression ]
-	postfix-expression . identifier
-	postfix-expressoin -> identifier
-
-unary-expression:
-	postfix-expression
-	unary-operator postfix-expression
-
-unary-operator: one of
-	+ -
-
-assignment-operator:
-	=
-
-type-assignment-operator:
-	:=
-
-constant-expression-range:
-	unary-expression ... unary-expression
-
-2.2) Declarations:
-
-declaration:
-	declaration-specifiers declarator-list-opt ;
-	ctf-specifier ;
-
-declaration-specifiers:
-	storage-class-specifier declaration-specifiers-opt
-	type-specifier declaration-specifiers-opt
-	type-qualifier declaration-specifiers-opt
-
-declarator-list:
-	declarator
-	declarator-list , declarator
-
-abstract-declarator-list:
-	abstract-declarator
-	abstract-declarator-list , abstract-declarator
-
-storage-class-specifier:
-	typedef
-
-type-specifier:
-	void
-	char
-	short
-	int
-	long
-	float
-	double
-	signed
-	unsigned
-	_Bool
-	_Complex
-	_Imaginary
-	struct-specifier
-	variant-specifier
-	enum-specifier
-	typedef-name
-	ctf-type-specifier
-
-align-attribute:
-	align ( unary-expression )
-
-struct-specifier:
-	struct identifier-opt { struct-or-variant-declaration-list-opt } align-attribute-opt
-	struct identifier align-attribute-opt
-
-struct-or-variant-declaration-list:
-	struct-or-variant-declaration
-	struct-or-variant-declaration-list struct-or-variant-declaration
-
-struct-or-variant-declaration:
-	specifier-qualifier-list struct-or-variant-declarator-list ;
-	declaration-specifiers-opt storage-class-specifier declaration-specifiers-opt 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 ;
-
-specifier-qualifier-list:
-	type-specifier specifier-qualifier-list-opt
-	type-qualifier specifier-qualifier-list-opt
-
-struct-or-variant-declarator-list:
-	struct-or-variant-declarator
-	struct-or-variant-declarator-list , struct-or-variant-declarator
-
-struct-or-variant-declarator:
-	declarator
-	declarator-opt : unary-expression
-
-variant-specifier:
-	variant identifier-opt variant-tag-opt { struct-or-variant-declaration-list }
-	variant identifier variant-tag
-
-variant-tag:
-	< unary-expression >
-
-enum-specifier:
-	enum identifier-opt { enumerator-list }
-	enum identifier-opt { enumerator-list , }
-	enum identifier
-	enum identifier-opt : declaration-specifiers { enumerator-list }
-	enum identifier-opt : declaration-specifiers { enumerator-list , }
-
-enumerator-list:
-	enumerator
-	enumerator-list , enumerator
-
-enumerator:
-	enumeration-constant
-	enumeration-constant assignment-operator unary-expression
-	enumeration-constant assignment-operator constant-expression-range
-
-type-qualifier:
-	const
-
-declarator:
-	pointer-opt direct-declarator
-
-direct-declarator:
-	identifier
-	( declarator )
-	direct-declarator [ unary-expression ]
-
-abstract-declarator:
-	pointer-opt direct-abstract-declarator
-
-direct-abstract-declarator:
-	identifier-opt
-	( abstract-declarator )
-	direct-abstract-declarator [ unary-expression ]
-	direct-abstract-declarator [ ]
-
-pointer:
-	* type-qualifier-list-opt
-	* type-qualifier-list-opt pointer
-
-type-qualifier-list:
-	type-qualifier
-	type-qualifier-list type-qualifier
-
-typedef-name:
-	identifier
-
-2.3) CTF-specific declarations
-
-ctf-specifier:
-	clock { ctf-assignment-expression-list-opt }
-	event { 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
-
-ctf-type-specifier:
-	floating_point { ctf-assignment-expression-list-opt }
-	integer { ctf-assignment-expression-list-opt }
-	string { ctf-assignment-expression-list-opt }
-	string
-
-ctf-assignment-expression-list:
-	ctf-assignment-expression ;
-	ctf-assignment-expression-list ctf-assignment-expression ;
-
-ctf-assignment-expression:
-	unary-expression assignment-operator unary-expression
-	unary-expression type-assignment-operator type-specifier
-	declaration-specifiers-opt storage-class-specifier declaration-specifiers-opt 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
--

-- 
2.2.1
Jonathan Haws | 21 Jan 21:55 2015

Out of Tree Kernel Module

I am developing an out-of-tree kernel module and would like to
instrument it for tracing.  I understand I will need to create an LTTng
probe in the modules source tree, however when I try to build my module,
I get errors stating that a header file for the subsystem doesn't exist
in the source tree.

Here is my trace event file:

#undef TRACE_SYSTEM
#define TRACE_SYSTEM sigma

#if !defined(_TRACE_SIGMA_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_SIGMA_H

#include <linux/tracepoint.h>

TRACE_EVENT(
    sigma_exarioctl,
    TP_PROTO(int cmd, int pin, int value),
    TP_ARGS(cmd, pin, value),

    /* LTTng doesn't need those */
    TP_STRUCT__entry(),
    TP_fast_assign(),
    TP_printk("", 0)
);

#endif

/* this part must be outside protection */
#include <trace/define_trace.h>

When I include that in my module, I do this:

#define CREATE_TRACE_POINTS
#include "exartrace.h"

However, when I build, I get the error:
<KERNELDIR>/include/trace/define_trace.h:83:43: fatal error:
trace/events/sigma.h: No such file or directory
 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)

Any thoughts on what I am doing wrong?

Thanks!
Jon
Wang Nan | 21 Jan 02:45 2015

Re: Fwd: perf data convert error

On 2015/1/20 20:15, Divya Vyas wrote:
> ---------- Forwarded message ----------
> From: Divya Vyas <edivya.vyas <at> gmail.com>
> Date: Tue, Jan 20, 2015 at 5:17 PM
> Subject: perf data convert error
> To: LKML <linux-kernel <at> vger.kernel.org>
> 
> 
> Hi,
> 
> 
> I am getting one error while converting the perf.data to CTF format .
> 
> 
> ./perf data convert -i perf.data --to-ctf dv_ctf
> ./perf: symbol lookup error: ./perf: undefined symbol:
> bt_ctf_stream_class_get_packet_context_type
> 
> While I created perf binary and below is the output :
> 
> make DEBUG=1 LIBBABELTRACE_DIR=/opt/libbabeltrace/
>   BUILD:   Doing 'make -j4' parallel build
> config/Makefile:139: The path 'python-config' is not executable.
> config/Makefile:507: Missing perl devel files. Disabling perl
> scripting support, consider installing perl-ExtUtils-Embed
> config/Makefile:538: No python-config tool was found
> config/Makefile:538: Python support will not be built
> config/Makefile:610: No bfd.h/libbfd found, install
> binutils-dev[el]/zlib-static to gain symbol demangling
> 
> Auto-detecting system features:
> ...                         dwarf: [ on  ]
> ...                         glibc: [ on  ]
> ...                          gtk2: [ on  ]
> ...                      libaudit: [ on  ]
> ...                        libbfd: [ OFF ]
> ...                        libelf: [ on  ]
> ...                       libnuma: [ on  ]
> ...                       libperl: [ OFF ]
> ...                     libpython: [ OFF ]
> ...                      libslang: [ on  ]
> ...                     libunwind: [ on  ]
> ...            libdw-dwarf-unwind: [ on  ]
> ...                 libbabeltrace: [ on  ]
> ...                          zlib: [ on  ]
> ...     DWARF post unwind library: libunwind
> 

Have you installed your libbabeltrace shared libraries properly?
Looks like libraries you used for compiling and for execution are different.

Try 'ldd perf' and you should find something like:

$ ldd /path/to/perf
	...
	libbabeltrace-ctf.so.1 => /path/to/libbabeltrace-ctf.so.1 (0x00007f312c861000)
	...

then nm:

$ nm /path/to/libbabeltrace-ctf.so.1 | grep bt_ctf_stream_class_get_packet_context_type
000000000002b3f0 T bt_ctf_stream_class_get_packet_context_type

If you don't get that symbol you should update your libbabeltrace runtime libraries.
Francis Giraldeau | 19 Jan 23:50 2015
Picon

Sequence of strings

Hi,

I would like to record a sequence of strings. Here is an example:

struct foo {
  string _my_string;
}; 

event {
  ...
  fields := struct {
    uint8_t _num;
    struct foo _items[_num];
  };
};

The program barectf does not allow it, and I wanted to know whether it's an implementation limitation or if CTF supports it at all.

Thanks,

Francis
_______________________________________________
lttng-dev mailing list
lttng-dev <at> lists.lttng.org
http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

Gmane