-.TH "LTTNG" "1" "July 17, 2012" "" ""
+.TH "LTTNG" "1" "December 3rd, 2012" "" ""
.SH "NAME"
-lttng \(em LTTng 2.0 tracer control command line tool
+lttng \(em LTTng 2.1.x tracer control command line tool
.SH "SYNOPSIS"
package.
LTTng uses a session daemon (lttng-sessiond(8)), acting as a tracing registry,
-which permits you to interact with multiple tracers (kernel and user-space)
+which allows you to interact with multiple tracers (kernel and user-space)
inside the same container, a tracing session. Traces can be gathered from the
kernel and/or instrumented applications (lttng-ust(3)). Aggregating and reading
those traces is done using the babeltrace(1) text viewer.
+We introduce the notion of \fBtracing domains\fP which is essentially a type of
+tracer (kernel or user space for now). In the future, we could see a third
+tracer being for instance an hypervisor. For some commands, you'll need to
+specify on which domain the command applies (-u or -k). For instance, enabling
+a kernel event, you must specify the kernel domain to the command so we know
+for which tracer this event is for.
+
In order to trace the kernel, the session daemon needs to be running as root.
LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is
in that group can interact with the root session daemon and thus trace the
.BR "\-n, \-\-no-sessiond"
Don't automatically spawn a session daemon.
.TP
-.BR "\-\-sessiond\-path"
+.BR "\-\-sessiond\-path PATH"
Set session daemon full binary path.
.TP
.BR "\-\-list\-options"
.nf
Add context to event(s) and/or channel(s).
-A context is basically extra information appended to a channel or event. For
-instance, you could ask the tracer to add the PID information within the
-"sched_switch" kernel event. You can also add performance monitoring unit
-counters (perf PMU) using the perf kernel API).
+A context is basically extra information appended to a channel. For instance,
+you could ask the tracer to add the PID information for all events in a
+channel. You can also add performance monitoring unit counters (perf PMU) using
+the perf kernel API).
For example, this command will add the context information 'prio' and two perf
counters (hardware branch misses and cache misses), to all events in the trace
Please take a look at the help (\-h/\-\-help) for a detailed list of available
contexts.
-If no channel and no event is given (\-c/\-e), the context is added to all
-channels (which applies automatically to all events in that channel). Otherwise
-the context will be added only to the channel (\-c) and/or event (\-e) indicated.
+If no channel is given (\-c), the context is added to all channels. Otherwise
+the context will be added only to the given channel (\-c).
If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
file.
Apply on session name.
\-c, \-\-channel NAME
Apply on channel name.
-\-e, \-\-event NAME
- Apply on event name.
\-k, \-\-kernel
Apply for the kernel tracer
\-u, \-\-userspace
Show this help
\-\-list-options
Simple listing of options
-\-s, \-\-session
+\-s, \-\-session NAME
Apply on session name
\-k, \-\-kernel
Apply to the kernel tracer
Discard event when subbuffers are full (default)
\-\-overwrite
Flight recorder mode : overwrites events when subbuffers are full
-\-\-subbuf-size
+\-\-subbuf-size SIZE
Subbuffer size in bytes (default: 4096, kernel default: 262144)
-\-\-num-subbuf
+\-\-num-subbuf NUM
Number of subbuffers (default: 4)
Needs to be a power of 2 for kernel and ust tracers
-\-\-switch-timer
+\-\-switch-timer USEC
Switch subbuffer timer interval in usec (default: 0)
Needs to be a power of 2 for kernel and ust tracers
-\-\-read-timer
+\-\-read-timer USEC
Read timer interval in usec (default: 200)
+\-\-output TYPE
+ Channel output type. Possible values: mmap, splice
.fi
.IP
Show summary of possible options and commands.
\-\-list-options
Simple listing of options
-\-s, \-\-session
+\-s, \-\-session NAME
Apply on session name
\-k, \-\-kernel
Apply for the kernel tracer
> file://...
Local filesystem full path.
-> net[6]://...
+> net://...
This will use the default network transport layer which is TCP for both
control (PORT1) and data port (PORT2). The default ports are
- respectively 5342 and 5343.
+ respectively 5342 and 5343. Note that net[6]:// is not yet supported.
> tcp[6]://...
Can only be used with -C and -D together
Show summary of possible options and commands.
\-\-list-options
Simple listing of options
-\-s, \-\-session
+\-s, \-\-session NAME
Apply on session name
-\-c, \-\-channel
+\-c, \-\-channel NAME
Apply on channel name
\-a, \-\-all
- Enable all tracepoints and syscalls
+ Enable all tracepoints and syscalls. This actually enable a single
+ wildcard event "*".
\-k, \-\-kernel
Apply for the kernel tracer
\-u, \-\-userspace
e.g.:
"*"
"app_component:na*"
-\-\-loglevel
- Tracepoint loglevel
+\-\-loglevel NAME
+ Tracepoint loglevel range from 0 to loglevel. Listed in the help (\-h).
+\-\-loglevel-only NAME
+ Tracepoint loglevel (only this loglevel).
+
+ The loglevel or loglevel-only options should be combined with a
+ tracepoint name or tracepoint wildcard.
\-\-probe [addr | symbol | symbol+offset]
Dynamic probe. Addr and offset can be octal (0NNN...), decimal (NNN...)
or hexadecimal (0xNNN...)
Show summary of possible options and commands.
\-\-list-options
Simple listing of options
-\-s, \-\-session
+\-s, \-\-session NAME
Apply on session name
+\-a, \-\-all-events
+ Disable all events. This does NOT disable "*" but rather
+ every known events of the session.
\-k, \-\-kernel
Apply for the kernel tracer
\-u, \-\-userspace
.nf
Stop tracing
-It will stop tracing for all tracers for a specific tracing session.
+It will stop tracing for all tracers for a specific tracing session. Before
+returning, the command checks for data availability meaning that it will wait
+until the trace is readable for the session. Use \-\-no-wait to avoid this
+behavior.
If NAME is omitted, the session name is taken from the .lttngrc file.
.fi
Show summary of possible options and commands.
\-\-list-options
Simple listing of options
+\-\-no-wait
+ Don't wait for data availability.
.fi
.IP
.BR lttng-health-check(3)
.SH "BUGS"
-With version 2.1 and earlier, if you start a tracing session and than enable
-kernel events, they are not recorded and the tracing session fails to stop. To
-fix this, simply enable events before starting the session.
-
If you encounter any issues or usability problem, please report it on our
mailing list <lttng-dev@lists.lttng.org> to help improve this project or
at https://bugs.lttng.org which is a bugtracker.
projects / lttng-tools.git / blobdiff