класс компонента кольцевого буфера ядра Linux от Babeltrace 2 (Babeltrace 2's Linux kernel ring buffer source component class)
Имя (Name)
babeltrace2-source.text.dmesg - Babeltrace 2's Linux kernel ring
buffer source component class
Описание (Description)
A Babeltrace 2 source.text.dmesg
message iterator reads the lines
of a Linux kernel ring buffer, as printed by the dmesg(1) tool,
and emits corresponding event messages.
Linux kernel ring buffer
lines (file or standard input)
|
| +----------------+
| | src.text.dmesg |
'-->| |
| out @--> Messages (single stream)
+----------------+
See babeltrace2-intro(7) to learn more about the Babeltrace 2
project and its core concepts.
A source.text.dmesg
message iterator names the events it creates
string
. Each event contain a single payload string field named
str
which contains the corresponding ring buffer line.
By default, a source.text.dmesg
message iterator reads the lines
of the standard input stream. You can make the message iterator
read the lines of a text file instead with the path
parameter.
By default, the message iterator tries to extract the timestamps
of the kernel ring buffer lines and use them as the created
events's timestamps. A typical dmesg(1) line looks like this:
[87166.510937] PM: Finishing wakeup.
The [87166.510937]
part is the timestamp to extract. When this
information is available, the component creates a clock class
which does NOT have the Unix epoch as its origin.
You can make the message iterator not extract timestamps from
lines with the no-extract-timestamp
parameter.
Note
It is possible that the output of dmesg(1) contains unsorted
lines, that is, their timestamps go back in time. You can see
this with the --show-delta
option of dmesg(1): some time
differences can be negative.
This is due to a 2019 change (see
<https://lwn.net/Articles/780556/>) to the kernel's ring
buffer API.
As of this version, a source.text.dmesg
message iterator
requires that the input kernel ring buffer lines be sorted by
timestamp (when they have timestamps), failing otherwise.
Параметры инициализации (Initialization parameters)
no-extract-timestamp
=yes
[optional boolean]
Do NOT extract timestamps from the kernel ring buffer lines:
set the created event's payload's str
field to the whole
line, including any timestamp prefix.
path
=PATH [optional string]
Read the kernel ring buffer lines from the file PATH instead
of the standard input stream.
Порты (Ports)
+----------------+
| src.text.dmesg |
| |
| out @
+----------------+
Output
out
Single output port.
Ошибки (баги) (Bugs)
If you encounter any issue or usability problem, please report it
on the Babeltrace bug tracker (see
<https://bugs.lttng.org/projects/babeltrace>).
Ресурсы (Resources)
The Babeltrace project shares some communication channels with
the LTTng project (see <https://lttng.org/>).
• Babeltrace website (see <https://babeltrace.org/>)
• Mailing list (see <https://lists.lttng.org>) for support and
development: lttng-dev@lists.lttng.org
• IRC channel (see <irc://irc.oftc.net/lttng>): #lttng
on
irc.oftc.net
• Bug tracker (see
<https://bugs.lttng.org/projects/babeltrace>)
• Git repository (see
<https://git.efficios.com/?p=babeltrace.git>)
• GitHub project (see <https://github.com/efficios/babeltrace>)
• Continuous integration (see
<https://ci.lttng.org/view/Babeltrace/>)
• Code review (see
<https://review.lttng.org/q/project:babeltrace>)