-.TH "LTTNG" "1" "February 9, 2012" "" ""
+.TH "LTTNG" "1" "December 3rd, 2012" "" ""
.SH "NAME"
-lttng \(em LTTng 2.0 tracer control command line tool
+lttng \(em LTTng 2.x tracer control command line tool
.SH "SYNOPSIS"
involving multiple concurrent processes and threads. Tracing across multiple
systems is also possible.
-The \fBlttng\fP command line tool from lttng-tools package is used to control
+The \fBlttng\fP command line tool from the lttng-tools package is used to control
both kernel and user-space tracing. Every interactions with the tracer should
be done by this tool or by the liblttng-ctl provided with the lttng-tools
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
kernel. Session daemons can co-exist meaning that you can have a session daemon
-running as Alice that can be use to trace her applications along side with a
-root daemon or even a Bob daemon. We highly recommand to start the session
+running as Alice that can be used to trace her applications along side with a
+root daemon or even a Bob daemon. We highly recommend to start the session
daemon at boot time for stable and long term tracing.
Every user-space applications instrumented with lttng-ust(3), will
.TP
.BR "\-v, \-\-verbose"
Increase verbosity.
-FIXME : details (\-v : sessiond verbose, \-vv : consumerd verbose, etc) ?
+Three levels of verbosity are available which are triggered by putting additional v to
+the option (\-vv or \-vvv)
.TP
.BR "\-q, \-\-quiet"
Suppress all messages (even errors).
.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"
Simple listing of lttng commands.
.SH "COMMANDS"
-.TP
+.PP
\fBadd-context\fP
-.nf
+.RS
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
data output:
-# lttng add-context \-k \-t prio \-t perf:branch-misses \-t perf:cache-misses
+.nf
+# lttng add-context \-k \-t prio \-t perf:branch-misses \\
+ \-t perf:cache-misses
+.fi
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 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).
If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
file.
-.fi
.B OPTIONS:
-.nf
-\-h, \-\-help
- Show summary of possible options and commands.
-\-s, \-\-session NAME
- 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
- Apply for the user-space tracer
-\-t, \-\-type TYPE
- Context type. You can repeat this option on the command line. Please
- use "lttng add-context \-h" to list all available types.
-.fi
-
-.IP
+.TP
+.BR "\-h, \-\-help"
+Show summary of possible options and commands.
+.TP
+.BR "\-s, \-\-session NAME"
+Apply on session name.
+.TP
+.BR "\-c, \-\-channel NAME"
+Apply on channel name.
+.TP
+.BR "\-k, \-\-kernel"
+Apply for the kernel tracer
+.TP
+.BR "\-u, \-\-userspace"
+Apply for the user-space tracer
+.TP
+.BR "\-t, \-\-type TYPE"
+Context type. You can repeat this option on the command line. Please
+use "lttng add-context \-h" to list all available types.
+.RE
+.PP
-.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 [OPTIONS] [NAME]
+.IP "\fBcreate\fP [NAME] [OPTIONS]
.nf
Create tracing session.
On creation, a \fB.lttngrc\fP file is created in your $HOME directory
containing the current session name. If NAME is omitted, a session name is
-automatically created having this form: 'auto-yyyymmdd-hhmms'.
+automatically created having this form: 'auto-yyyymmdd-hhmmss'.
If no \fB\-o, \-\-output\fP is specified, the traces will be written in
$HOME/lttng-traces.
+
+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:
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).
+
+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.
+
+> 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
+
+NOTE: IPv6 address MUST be enclosed in brackets '[]' (rfc2732)
+
+.B EXAMPLES:
+
+# lttng create -U net://192.168.1.42
+Uses TCP and default ports for the given destination.
+
+# lttng create -U net6://[fe80::f66d:4ff:fe53:d220]
+Uses TCP, default ports and IPv6.
+
+# lttng create s1 -U net://myhost.com:3229
+Create session s1 and set its consumer to myhost.com on port 3229 for control.
.fi
.IP
.nf
\-h, \-\-help
Show summary of possible options and commands.
+\-a, \-\-all
+ Destroy all sessions
\-\-list-options
Simple listing of options
.fi
.nf
Enable tracing channel
+To enable an event, you must enable both the event and the channel that
+contains it.
+
If \fB\-s, \-\-session\fP is omitted, the session name is taken from the .lttngrc
file.
+
+It is important to note that if a certain type of buffers is used, the session
+will be set with that type and all other subsequent channel needs to have the
+same type.
+
+Note that once the session has been started and enabled on the tracer side,
+it's not possible anymore to enable a new channel for that session.
.fi
.B OPTIONS:
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
- Subbuffer size in bytes (default: 4096, kernel default: 262144)
-\-\-num-subbuf
- Number of subbufers (default: 4)
- Needs to be a power of 2 for kernel and ust tracers
-\-\-switch-timer
- Switch subbuffer timer interval in usec (default: 0)
- Needs to be a power of 2 for kernel and ust tracers
-\-\-read-timer
- Read timer interval in usec (default: 200)
+\-\-subbuf-size SIZE
+ Subbuffer size in bytes {+k,+M,+G}
+ (default UST uid: 131072, UST pid: 4096, kernel: 262144, metadata: 4096)
+ Rounded up to the next power of 2.
+
+ The minimum subbuffer size, for each tracer, is the max value between
+ the default above and the system page size. You can issue this command
+ to get the current page size on your system: \fB$ getconf PAGE_SIZE\fP
+\-\-num-subbuf NUM
+ Number of subbuffers. (default UST uid: 4, UST pid: 4, kernel: 4, metadata: 2)
+ Rounded up to the next power of 2.
+\-\-switch-timer USEC
+ Switch subbuffer timer interval in µsec.
+ (default UST uid: 0, UST pid: 0, kernel: 0, metadata: 0)
+\-\-read-timer USEC
+ Read timer interval in µsec.
+ (default UST uid: 0, UST pid: 0, kernel: 200000, metadata: 0)
+\-\-output TYPE
+ Channel output type. Possible values: mmap, splice
+ (default UST uid: mmap, UST pid: mmap, kernel: splice, metadata: mmap)
+\-\-buffers-uid
+ Use per UID buffer (\-u only). Buffers are shared between applications
+ that have the same UID.
+\-\-buffers-pid
+ Use per PID buffer (\-u only). Each application has its own buffers.
+\-\-buffers-global
+ Use shared buffer for the whole system (\-k only)
+\-C, \-\-tracefile-size SIZE
+ Maximum size of each tracefile within a stream (in bytes).
+ 0 means unlimited. (default: 0)
+\-W, \-\-tracefile-count COUNT
+ Used in conjunction with \-C option, this will limit the number
+ of files created to the specified count. 0 means unlimited. (default: 0)
+
+.B EXAMPLES:
+
+$ lttng enable-channel -C 4096 -W 32 chan1
+For each stream, the maximum size of each trace file will be 4096 bytes, and
+there will be a maximum of 32 different files. The file count is appended after
+the stream number as seen in the following example. The last trace file is
+smaller than 4096 since it was not completely filled.
+
+ ~/lttng-traces/[...]/chan1_0_0 (4096)
+ ~/lttng-traces/[...]/chan1_0_1 (4096)
+ ~/lttng-traces/[...]/chan1_0_2 (3245)
+ ~/lttng-traces/[...]/chan1_1_0 (4096)
+ ...
+
+$ lttng enable-channel -C 4096
+This will create trace files of 4096 bytes and will create new ones as long as
+there is data available.
.fi
.IP
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...)
Dynamic function entry/return probe. Addr and offset can be octal
(0NNN...), decimal (NNN...) or hexadecimal (0xNNN...)
\-\-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.
+ 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.
+
+\-\-filter 'expression'
+ Set a filter on a newly enabled event. Filter expression on event
+ fields and context. Event recording depends on evaluation. Only
+ specify on first activation of a given event within a session.
+ Filter only allowed when enabling events within a session before
+ tracing is started. If the filter fails to link with the event
+ within the traced domain, the event will be discarded.
+ Currently, filter is only implemented for the user-space tracer.
+
+ Expression examples:
+
+ 'intfield > 500 && intfield < 503'
+ '(stringfield == "test" || intfield != 10) && intfield > 33'
+ 'doublefield > 1.1 && intfield < 5.3'
+
+ Wildcards are allowed at the end of strings:
+ 'seqfield1 == "te*"'
+ In string literals, the escape character is a '\\'. Use '\\*' for
+ the '*' character, and '\\\\' for the '\\' character. Wildcard
+ match any sequence of characters, including an empty sub-string
+ (match 0 or more characters).
+
+ Context information can be used for filtering. The examples
+ below show usage of context filtering on process name (with a
+ wildcard), process ID range, and unique thread ID for filtering.
+ The process and thread ID of running applications can be found
+ under columns "PID" and "LWP" of the "ps -eLf" command.
+
+ '$ctx.procname == "demo*"'
+ '$ctx.vpid >= 4433 && $ctx.vpid < 4455'
+ '$ctx.vtid == 1234'
.fi
.IP "\fBdisable-channel\fP NAME[,NAME2,...] [\-k|\-u] [OPTIONS]"
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
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
With no arguments, it will list available tracing session(s).
+With the session name, it will display the details of the session including
+the trace file path, the associated channels and their state (activated
+and deactivated), the activated events and more.
+
With \-k alone, it will list all available kernel events (except the system
calls events).
With \-u alone, it will list all available user-space events from registered
\-\-list-options
Simple listing of options
\-k, \-\-kernel
- Select kernel domain (FIXME : apparition de la notion de "domain" ici)
+ Select kernel domain
\-u, \-\-userspace
Select user-space domain.
-Session options:
+.B SESSION OPTIONS:
+
\-c, \-\-channel NAME
List details of a channel
\-d, \-\-domain
.IP
-.IP "\fBstart\fP [OPTIONS] [NAME]"
+.IP "\fBsnapshot\fP ACTION"
+.nf
+Snapshot command for LTTng session.
+.fi
+
+.B OPTIONS:
+
+.nf
+\-h, \-\-help
+ Show summary of possible options and commands.
+\-\-list-options
+ Simple listing of options
+.fi
+
+.B ACTION:
+
+.nf
+\fBadd-output\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] <URL> | -C <URL> -D <URL>
+
+Setup and add an snapshot output for a session. Output are the destination
+where the snapshot will be sent. Only one output is permitted. To change it,
+you'll need to delete it and add back the new one.
+
+\fBdel-output\fP ID | NAME [-s <NAME>]
+
+Delete an output for a session using the ID. You can either specify the
+output's ID that can be found with list-output or the name.
+
+\fBlist-output\fP [-s <NAME>]
+
+List the output of a session. Attributes of the output are printed.
+
+\fBrecord\fP [-m <SIZE>] [-s <NAME>] [-n <NAME>] [<URL> | -C <URL> -D <URL>]
+
+Snapshot a session's buffer(s) for all domains. If an URL is specified, it is
+used instead of a previously added output. Specifying only a name or/and a max
+size will override the current output values. For instance, you can record a
+snapshot with a custom maximum size or with a different name.
+
+$ lttng add-output -n mysnapshot file:///data/snapshot
+[...]
+$ lttng snapshot record -n new_name_snapshot
+
+The above will create a snapshot in /data/snapshot/new_name_snapshot* directory
+rather then in mysnapshot*/
+.fi
+
+.B LONG OPTIONS
+
+.nf
+\-s, \-\-session NAME
+ Apply to session name.
+\-n, \-\-name NAME
+ Name of the snapshot's output.
+\-m, \-\-max-size SIZE
+ Maximum size in bytes of the snapshot. The maxium size does not
+ include the metadata file.
+\-C, \-\-ctrl-url URL
+ Set control path URL. (Must use -D also)
+\-D, \-\-data-url URL
+ Set data path URL. (Must use -C also)
+.fi
+
+.IP
+
+.IP "\fBstart\fP [NAME] [OPTIONS]"
.nf
Start tracing
.IP
-.IP "\fBstop\fP [OPTIONS] [NAME]"
+.IP "\fBstop\fP [NAME] [OPTIONS]"
.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
By default, the babeltrace viewer will be used for text viewing.
-The SESSION_NAME is an optional session name. If not specified, lttng will get
-it from the configuration file (.lttngrc).
+If SESSION_NAME is omitted, the session name is taken from the .lttngrc file.
+
.fi
.B OPTIONS:
to the arguments
.fi
+.SH "EXIT VALUES"
+On success 0 is returned and a positive value on error. Value of 1 means a command
+error, 2 an undefined command, 3 a fatal error and 4 a command warning meaning that
+something went wrong during the command.
+
+Any other value above 10, please refer to
+.BR <lttng/lttng-error.h>
+for a detailed list or use lttng_strerror() to get a human readable string of
+the error code.
+
+.PP
.SH "ENVIRONMENT VARIABLES"
.PP
.PP
.PP
-.IP "LTTNG_SESSIOND_PATH_ENV"
+.IP "LTTNG_SESSIOND_PATH"
Allows one to specify the full session daemon binary path to lttng command line
tool. You can also use \-\-sessiond-path option having the same effect.
.SH "SEE ALSO"
-
-.PP
-babeltrace(1), lttng-ust(3), lttng-sessiond(8)
-.PP
+.BR babeltrace(1),
+.BR lttng-ust(3),
+.BR lttng-sessiond(8),
+.BR lttng-relayd(8),
+.BR lttng-health-check(3)
.SH "BUGS"
-.PP
-No show stopper bugs known yet at this stable version.
-
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.
+mailing list <lttng-dev@lists.lttng.org> to help improve this project or
+at https://bugs.lttng.org which is a bugtracker.
.SH "CREDITS"
.PP
.PP
Thanks to Yannick Brosseau without whom this project would never have been so
lean and mean! Also thanks to the Ericsson teams working on tracing which
-helped us greatly with detailled bug reports and unusual test cases.
+helped us greatly with detailed bug reports and unusual test cases.
Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
maintainer) and Jon Bernard for our Debian packages.
projects / lttng-tools.git / blobdiff