table of contents
LTTNG-ADD-CONTEXT(1) | LTTng Manual | LTTNG-ADD-CONTEXT(1) |
NAME¶
lttng-add-context - Add context fields to an LTTng channelSYNOPSIS¶
Add context fields to a channel:lttng [GENERAL OPTIONS] add-context (--kernel | --userspace | --jul | --log4j) [--session=SESSION] [--channel=CHANNEL] --type=TYPE [--type=TYPE]...
List the available context fields:
lttng [GENERAL OPTIONS] add-context --list
DESCRIPTION¶
The lttng add-context command adds one or more context fields to a channel.Channels are created with the lttng-enable-channel(1) command.
When context fields are added to a channel, all the events emitted within this channel contain the dynamic values of those context fields.
If the --session option is omitted, the current tracing session is used. If the --channel option is omitted, the context fields are added to all the selected tracing session’s channels.
Many context fields can be added to a channel at once by repeating the --type option.
perf counters are available as per-CPU (perf:cpu: prefix) as well as per-thread (perf:thread: prefix) counters. Currently, per-CPU counters can only be used in the Linux kernel tracing domain, while per-thread counters can only be used in the user space tracing domain.
It is also possible to enable PMU counters by raw ID using the perf:cpu:raw:rN:NAME (Linux kernel tracing domain) or perf:thread:raw:rN:NAME (user space tracing domain), with:
N
NAME
Application-specific context fields can be added to a channel using the following syntax:
$app.PROVIDER:TYPE
with:
PROVIDER
TYPE
Note
Make sure to single-quote the type when running the command from a shell, as $ is a special character for variable substitution in most shells.
Use the --list option without other arguments to list the available context field names.
OPTIONS¶
General options are described in lttng(1).Domain¶
One of:-j, --jul
-k, --kernel
-l, --log4j
-u, --userspace
Target¶
-c CHANNEL, --channel=CHANNEL-s SESSION, --session=SESSION
Context¶
--list-t TYPE, --type=TYPE
Program information¶
-h, --helpThis option, like lttng-help(1), attempts to launch /usr/bin/man to view the command’s man page. The path to the man pager can be overridden by the LTTNG_MAN_BIN_PATH environment variable.
--list-options
ENVIRONMENT VARIABLES¶
LTTNG_ABORT_ON_ERRORLTTNG_HOME
LTTNG_MAN_BIN_PATH
LTTNG_SESSION_CONFIG_XSD_PATH
LTTNG_SESSIOND_PATH
The --sessiond-path option has precedence over this environment variable.
Note that the lttng-create(1) command can spawn an LTTng session daemon automatically if none is running. See lttng-sessiond(8) for the environment variables influencing the execution of the session daemon.
FILES¶
$LTTNG_HOME/.lttngrcThis is where the per-user current tracing session is stored between executions of lttng(1). The current tracing session can be set with lttng-set-session(1). See lttng-create(1) for more information about tracing sessions.
$LTTNG_HOME/lttng-traces
$LTTNG_HOME/.lttng
$LTTNG_HOME/.lttng/sessions
/usr/local/etc/lttng/sessions
Note
$LTTNG_HOME defaults to $HOME when not explicitly set.
EXIT STATUS¶
01
2
3
4
BUGS¶
If you encounter any issue or usability problem, please report it on the LTTng bug tracker <https://bugs.lttng.org/projects/lttng-tools>.RESOURCES¶
COPYRIGHTS¶
This program is part of the LTTng-tools project.LTTng-tools is distributed under the GNU General Public License version 2 <http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html>. See the LICENSE <https://github.com/lttng/lttng-tools/blob/master/LICENSE> file for details.
THANKS¶
Special thanks to Michel Dagenais and the DORSAL laboratory <http://www.dorsal.polymtl.ca/> at École Polytechnique de Montréal for the LTTng journey.Also thanks to the Ericsson teams working on tracing which helped us greatly with detailed bug reports and unusual test cases.
AUTHORS¶
LTTng-tools was originally written by Mathieu Desnoyers, Julien Desfossez, and David Goulet. More people have since contributed to it.LTTng-tools is currently maintained by Jérémie Galarneau <mailto:jeremie.galarneau@efficios.com>.
SEE ALSO¶
lttng(1)01/09/2017 | LTTng 2.9.3 |