-.TH "LTTNG" "1" "February 05th, 2014" "" ""
+.TH "LTTNG" "1" "May 13th, 2014" "" ""
.SH "NAME"
lttng \(em LTTng 2.x tracer control command line tool
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).
+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
+For example, this command will add the context information 'prio' and two per-CPU
+perf counters (hardware branch misses and cache misses), to all events in the trace
data output:
.nf
-# lttng add-context \-k \-t prio \-t perf:branch-misses \\
- \-t perf:cache-misses
+# lttng add-context \-k \-t prio \-t perf:cpu:branch-misses \\
+ \-t perf:cpu:cache-misses
.fi
Please take a look at the help (\-h/\-\-help) for a detailed list of available
contexts.
+Perf counters are available as per-CPU ("perf:cpu:...") and per-thread
+("perf:thread:...") counters. Currently, per-CPU counters can only be
+used with the kernel tracing domain, and per-thread counters can only be
+used with the UST tracing domain.
+
If no channel is given (\-c), the context is added to all channels that were
already enabled. If the session has no channel, a default channel is created.
Otherwise the context will be added only to the given channel (\-c).
# lttng create calibrate-function
# lttng enable-event calibrate \-\-kernel \\
\-\-function lttng_calibrate_kretprobe
-# lttng add-context \-\-kernel \-t perf:LLC-load-misses \\
- \-t perf:LLC-store-misses \\
- \-t perf:LLC-prefetch-misses
+# lttng add-context \-\-kernel \-t perf:cpu:LLC-load-misses \\
+ \-t perf:cpu:LLC-store-misses \\
+ \-t perf:cpu:LLC-prefetch-misses
# lttng start
# for a in $(seq 1 10); do \\
lttng calibrate \-\-kernel \-\-function;
Discard event when subbuffers are full (default)
.TP
.BR "\-\-overwrite"
-Flight recorder mode : overwrites events when subbuffers are full
+Flight recorder mode: overwrites events when subbuffers are full. The
+number of subbuffer must be 2 or more.
.TP
.BR "\-\-subbuf-size SIZE"
Subbuffer size in bytes {+k,+M,+G}.
.BR "\-C, \-\-tracefile-size SIZE"
Maximum size of each tracefile within a stream (in bytes).
0 means unlimited. (default: 0)
+Note: traces generated with this option may inaccurately report
+discarded events as of CTF 1.8.
.TP
.BR "\-W, \-\-tracefile-count COUNT"
Used in conjunction with \-C option, this will limit the number of files
.BR "\-\-syscall"
System call event. Enabling syscalls tracing (kernel tracer), you will
not be able to disable them with disable-event. This is a known
-limitation. You can disable the entire channel to do the trick.
+limitation. You can disable the entire channel to do the trick. Also note
+that per-syscall selection is not supported yet. Use with "-a" to enable
+all syscalls.
.TP
.BR "\-\-filter 'expression'"
Set a filter on a newly enabled event. Filter expression on event
'$ctx.vtid == 1234'
.fi
+Context information is available to all filters whether or not the add-context
+command has been used to add it to the event's channel, as long as the context
+field exists for that domain. For example, the filter examples given above will
+never fail to link: no add-context is required for the event's channel.
+
.TP
.BR "\-x, \-\-exclude LIST"
Add exclusions to UST tracepoints:
Disable tracing channel
Disabling a channel disables the tracing of all of the channel's events. A channel
-can be reenabled by calling \fBlttng enable-channel NAME\fP again.
+can be re-enabled by calling \fBlttng enable-channel NAME\fP again.
If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
file.
.RE
.PP
+.PP
+\fBload\fP [OPTIONS] [NAME]
+.RS
+Load tracing session configuration
+
+If NAME is omitted, all session configurations found in both the user's session
+configuration directory and the system session configuration directory will be
+loaded.
+
+.B OPTIONS:
+
+.TP
+.BR "\-h, \-\-help"
+Show summary of possible options and commands.
+.TP
+.BR "\-a, \-\-all"
+Load all session configurations (default).
+.TP
+.BR "\-i, \-\-input-path PATH"
+Specify the input path for session configurations.
+.TP
+.BR "\-f, -\-force"
+Overwrite current session configuration(s) if a session of the same name
+already exists.
+.RE
+.PP
+
+.PP
+\fBsave\fP [OPTIONS] [SESSION]
+.RS
+Save tracing session configuration
+
+If SESSION is omitted, all session configurations will be saved to individual
+\fB.lttng\fP files under the user's session configuration directory (default:
+~/.lttng/sessions/ or /var/run/lttng/sessions/ for root user). The default
+session configuration file naming scheme is \fBSESSION.lttng\fP.
+
+.B OPTIONS:
+
+.TP
+.BR "\-h, \-\-help"
+Show summary of possible options and commands.
+.TP
+.BR "\-a, \-\-all"
+Save all session configurations (default).
+.TP
+.BR "\-o, \-\-output-path PATH"
+Specify the output path for saved sessions. This overrides the default session
+configuration directory.
+.TP
+.BR "\-f, -\-force"
+Overwrite session configuration file if session name clashes.
+.RE
+.PP
+
.PP
\fBset-session\fP NAME [OPTIONS]
.RS
Maximum size in bytes of the snapshot. The maxium size does not include the
metadata file. Human readable format is accepted: {+k,+M,+G}. For instance,
\-\-max-size 5M
+
+The minimum size of a snapshot is computed by multiplying the total amount of
+streams in the session by the largest subbuffer size. This is to ensure
+fairness between channels when extracting data.
.TP
.BR "\-C, \-\-ctrl-url URL"
Set control path URL. (Must use -D also)
tool. You can also use \-\-sessiond-path option having the same effect.
.PP
+.PP
+.IP "LTTNG_SESSION_CONFIG_XSD_PATH"
+Set the path in which the \fBsession.xsd\fP session configuration schema may be
+found.
+.PP
+
.SH "SEE ALSO"
.BR babeltrace(1),
.BR lttng-ust(3),
projects / lttng-tools.git / blobdiff