From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathieu.desnoyers@efficios.com (Mathieu Desnoyers) Date: Tue, 28 Apr 2020 15:12:26 -0400 Subject: [lttng-dev] [RFC PATCH CTF 3/4] Clarify that timestamp begin/end need to be complete clock values In-Reply-To: <20200428191227.16560-1-mathieu.desnoyers@efficios.com> References: <20200428191227.16560-1-mathieu.desnoyers@efficios.com> Message-ID: <20200428191227.16560-3-mathieu.desnoyers@efficios.com> Signed-off-by: Mathieu Desnoyers --- common-trace-format-specification.md | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/common-trace-format-specification.md b/common-trace-format-specification.md index 55d0601..5732e92 100644 --- a/common-trace-format-specification.md +++ b/common-trace-format-specification.md @@ -837,11 +837,12 @@ TSDL metadata): 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 - beginning of an event packet is guaranteed to be above or equal the - timestamps at the beginning of any prior packet within the same - stream. 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. + beginning of an event packet is guaranteed to be grater than or + equal to timestamps at the beginning of any prior packet within the + same stream. The timestamp at the end of an event packet is + guaranteed to be less than or equal to 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 @@ -1580,7 +1581,8 @@ stream { }; ~~~ -For a N-bit integer type referring to a clock, if the integer overflows +Within the stream event context, event context, and event payload, +fields of 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 @@ -1589,8 +1591,8 @@ 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. - +the beginning and the end of each packet. Those are required to be +complete representations of the clock value. ## A. Helper macros -- 2.11.0