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-rw-r--r--docs/users_guide/eventlog-formats.rst29
1 files changed, 15 insertions, 14 deletions
diff --git a/docs/users_guide/eventlog-formats.rst b/docs/users_guide/eventlog-formats.rst
index b8ad8f32d9..1affa13151 100644
--- a/docs/users_guide/eventlog-formats.rst
+++ b/docs/users_guide/eventlog-formats.rst
@@ -36,13 +36,14 @@ files.
cannot be changed. Tools should ignore extra fields at the
end of the event record.
-The event-log stream begins with a header describing the event types present in
-the file. The header is followed by the event records themselves, each of which
-consist of a 64-bit timestamp
+The event-log stream begins with a header describing the event types (``EventType``) present in
+the file. The header is followed by the event records (``Event``) themselves, each of which
+start with the event type id and a 64-bit timestamp:
.. code-block:: none
- log : EVENT_HEADER_BEGIN
+ EventLog :
+ EVENT_HEADER_BEGIN
EventType*
EVENT_HEADER_END
EVENT_DATA_BEGIN
@@ -51,25 +52,25 @@ consist of a 64-bit timestamp
EventType :
EVENT_ET_BEGIN
- Word16 -- unique identifier for this event
- Int16 -- >=0 size of the event in bytes (minus the header)
+ Word16 -- event type id, unique identifier for this event
+ Int16 -- >=0 size of the event record in bytes (minus the event type id and timestamp fields)
-- -1 variable size
- Word32 -- length of the next field in bytes
- Word8* -- string describing the event
- Word32 -- length of the next field in bytes
+ Word32 -- size of the event description in bytes
+ Word8* -- event description, UTF8 encoded string describing the event
+ Word32 -- size of the extra info in bytes
Word8* -- extra info (for future extensions)
EVENT_ET_END
Event :
- Word16 -- event_type
- Word64 -- time (nanosecs)
- [Word16] -- length of the rest (for variable-sized events only)
- ... extra event-specific info ...
+ Word16 -- event type id, as included in the event log header
+ Word64 -- timestamp (nanoseconds)
+ [Word16] -- length of the rest (optional, for variable-sized events only)
+ ... event specific info ...
There are two classes of event types:
- *Fixed size*: All event records of a fixed-sized type are of the same
- length, given in the header event-log header.
+ length, the size given in the header event-log header.
- *Variable size*: Each event record includes a length field.