.SH "COMMANDS"
.PP
-\fBadd-context\fP
+\fBadd-context\fP [OPTIONS]
.RS
Add context to event(s) and/or channel(s).
.RE
.PP
-.IP
-
-.IP "\fBcalibrate\fP"
-.nf
+.PP
+\fBcalibrate\fP [OPTIONS]
+.RS
Quantify LTTng overhead
The LTTng calibrate command can be used to find out the combined average
information (see lttng add-context \-\-help to see the list of available PMU
counters).
+.nf
# 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 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 start
# for a in $(seq 1 10); do \\
lttng calibrate \-\-kernel \-\-function;
done
# lttng destroy
-# babeltrace $(ls \-1drt ~/lttng-traces/calibrate-function-* | tail \-n 1)
+# babeltrace $(ls \-1drt ~/lttng-traces/calibrate-function-* \\
+ | tail \-n 1)
+.fi
The output from babeltrace can be saved to a text file and opened in a
spreadsheet (e.g. oocalc) to focus on the per-PMU counter delta between
The average result, for the i7, on 10 samples:
+.nf
Average Std.Dev.
perf_LLC_load_misses: 5.0 0.577
perf_LLC_store_misses: 1.6 0.516
perf_LLC_prefetch_misses: 9.0 14.742
+.fi
As we can notice, the load and store misses are relatively stable across runs
(their standard deviation is relatively low) compared to the prefetch misses.
accounted for quite precisely, but prefetches within a function seems to behave
too erratically (not much causality link between the code executed and the CPU
prefetch activity) to be accounted for.
-.fi
.B OPTIONS:
-.nf
-\-h, \-\-help
- Show summary of possible options and commands.
-\-k, \-\-kernel
- Apply for the kernel tracer
-\-u, \-\-userspace
- Apply for the user-space tracer
-\-\-function
- Dynamic function entry/return probe (default)
-.fi
-
-.IP
+.TP
+.BR "\-h, \-\-help"
+Show summary of possible options and commands.
+.TP
+.BR "\-k, \-\-kernel"
+Apply for the kernel tracer
+.TP
+.BR "\-u, \-\-userspace"
+Apply for the user-space tracer
+.TP
+.BR "\-\-function"
+Dynamic function entry/return probe (default)
+.RE
+.PP
-.IP "\fBcreate\fP [NAME] [OPTIONS]
-.nf
+.PP
+.IP \fBcreate\fP [NAME] [OPTIONS]
+.RS
Create tracing session.
A tracing session contains channel(s) which contains event(s). It is domain
The $HOME environment variable can be overridden by defining the environment
variable LTTNG_HOME. This is useful when the user running the commands has
a non-writeable home directory.
-.fi
.B OPTIONS:
-.nf
-\-h, \-\-help
- Show summary of possible options and commands.
-\-\-list-options
- Simple listing of options
-\-o, \-\-output PATH
- Specify output path for traces
-\-\-no-output
- Traces will not be outputed
-\-\-snapshot
- Set the session in snapshot mode. Created in no-output mode
- and uses the URL, if one, as the default snapshot output.
- Every channel will be set in overwrite mode and with mmap
- output (splice not supported).
+.TP
+.BR "\-h, \-\-help"
+Show summary of possible options and commands.
+.TP
+.BR "\-\-list-options"
+Simple listing of options
+.TP
+.BR "\-o, \-\-output PATH"
+Specify output path for traces
+.TP
+.BR "\-\-no-output"
+Traces will not be outputed
+.TP
+.BR "\-\-snapshot"
+Set the session in snapshot mode. Created in no-output mode and uses the
+URL, if one, as the default snapshot output. Every channel will be set
+in overwrite mode and with mmap output (splice not supported).
+.TP
+.BR "\-U, \-\-set-url=URL"
+Set URL for the consumer output destination. It is persistent for the
+session lifetime. Redo the command to change it. This will set both data
+and control URL for network.
+.TP
+.BR "\-C, \-\-ctrl-url=URL"
+Set control path URL. (Must use -D also)
+.TP
+.BR "\-D, \-\-data-url=URL"
+Set data path URL. (Must use -C also)
+.PP
Using these options, each API call can be controlled individually. For
instance, \-C does not enable the consumer automatically. You'll need the \-e
option for that.
-\-U, \-\-set-url=URL
- Set URL for the consumer output destination. It is persistent for the
- session lifetime. Redo the command to change it. This will set both
- data and control URL for network.
-\-C, \-\-ctrl-url=URL
- Set control path URL. (Must use -D also)
-\-D, \-\-data-url=URL
- Set data path URL. (Must use -C also)
-
.B URL FORMAT:
proto://[HOST|IP][:PORT1[:PORT2]][/TRACE_PATH]
Supported protocols are (proto):
-> file://...
- Local filesystem full path.
+.TP
+.BR "file://..."
+Local filesystem full path.
-> 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. Note that net[6]:// is not yet supported.
+.TP
+.BR "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. Note that net[6]:// is not yet supported.
-> tcp[6]://...
- Can only be used with -C and -D together
+.TP
+.BR "tcp[6]://..."
+Can only be used with -C and -D together
NOTE: IPv6 address MUST be enclosed in brackets '[]' (rfc2732)
.B EXAMPLES:
+.nf
# lttng create -U net://192.168.1.42
+.fi
Uses TCP and default ports for the given destination.
+.nf
# lttng create -U net6://[fe80::f66d:4ff:fe53:d220]
+.fi
Uses TCP, default ports and IPv6.
+.nf
# lttng create s1 -U net://myhost.com:3229
-Create session s1 and set its consumer to myhost.com on port 3229 for control.
.fi
+Create session s1 and set its consumer to myhost.com on port 3229 for control.
+.RE
+.PP
-.IP
-
-.IP "\fBdestroy\fP [OPTIONS] [NAME]"
-.nf
+.PP
+\fBdestroy\fP [NAME] [OPTIONS]
+.RS
Teardown tracing session
Free memory on the session daemon and tracer side. It's gone!
If NAME is omitted, the session name is taken from the .lttngrc file.
-.fi
.B OPTIONS:
-.nf
-\-h, \-\-help
- Show summary of possible options and commands.
-\-a, \-\-all
- Destroy all sessions
-\-\-list-options
- Simple listing of options
-.fi
-
-.IP
+.TP
+.BR "\-h, \-\-help"
+Show summary of possible options and commands.
+.TP
+.BR "\-a, \-\-all"
+Destroy all sessions
+.TP
+.BR "\-\-list-options"
+Simple listing of options
+.RE
+.PP
.IP "\fBenable-channel\fP NAME[,NAME2,...] [-k|-u] [OPTIONS]"
.nf