Cleanup: spaghetti function return path
[lttng-tools.git] / doc / man / lttng-sessiond.8
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1.TH "LTTNG-SESSIOND" "8" "January 31, 2012" "" ""
2
3.SH "NAME"
4lttng-sessiond \(em LTTng 2.x central tracing registry session daemon.
5
6.SH "SYNOPSIS"
7
8.PP
9.nf
10lttng-sessiond [OPTIONS]
11.fi
12.SH "DESCRIPTION"
13
14.PP
15The LTTng project aims at providing highly efficient tracing tools for Linux.
16It's tracers help tracking down performance issues and debugging problems
17involving multiple concurrent processes and threads. Tracing across multiple
18systems is also possible.
19
20The session daemon, acting as a tracing registry, allow you to interact with
21multiple tracers (kernel and user-space) inside the same container, a tracing
22session. Trace can be gathered from the kernel and/or instrumented applications
23(lttng-ust(3)). Aggregating those traces is done using a viewer, like the
24babeltrace(1) text viewer.
25
26In order to trace the kernel, the session daemon needs to be running as root.
27LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is
28in that group can interact with the root session daemon and thus trace the
29kernel. Session daemons can co-exist meaning that you can have a session daemon
30running as Alice that can be used to trace her applications along side with a
31root daemon or even a Bob daemon. We highly recommend to start the session
32daemon at boot time for stable and long term tracing.
33
34The session daemon is in charge of managing trace data consumers by spawning
35them when the time has come. The user don't need to manage the lttng-consumerd.
36.SH "OPTIONS"
37
38.PP
39This program follow the usual GNU command line syntax with long options starting with
40two dashes. Below is a summary of the available options.
41.PP
42
43.TP
44.BR "-h, --help"
45Show summary of possible options and commands
46.TP
47.BR "-v, --verbose"
48Increase verbosity
49
50There is three debugging level which will print on stderr. Maximum verbosity is
51\fB-vvv\fP.
52.TP
53.BR " --verbose-consumer"
54Verbose mode for consumer. Activate DBG() macro.
55.TP
56.BR "-d, --daemonize"
57Start as a daemon
58.TP
59.BR "-b, --background"
60Start as a daemon, keeping console open
61.TP
62.BR "-g, --group=NAME"
63Specify the tracing group name. (default: tracing)
64.TP
65.BR "-V, --version"
66Show version number
67.TP
68.BR "-S, --sig-parent"
69Send SIGUSR1 to parent pid to notify readiness.
70
71This is used by \fBlttng(1)\fP to get notified when the session daemon is ready
72to accept command. When building a third party tool over liblttng-ctl, this option
73can be very handy to synchronize the control tool and the session daemon.
74.TP
75.BR "-q, --quiet"
76No output at all.
77.TP
78.BR " --no-kernel"
79No kernel tracer support
80.TP
81.BR " --agent-tcp-port"
82Agent application registration TCP port (default: 5345)
83.TP
84.BR " --kmod-probes=probe1, probe2, ..."
85Specify the kernel modules containing LTTng probes to load by the session daemon.
86Only the component name of the probe needs to be specified, e.g. to load the
87lttng-probe-irq and lttng-probe-sched use: --kmod-probes="irq, sched".
88.TP
89.BR " --extra-kmod-probes=probe1, probe2, ..."
90Specify extra kernel modules containing LTTng probes to be loaded by the session
91daemon. The list follows the format of the \fB--kmod-probes\fP option.
92This list is appended to the list provided by \fB--kmod-probes\fP or, if
93\fB--kmod-probes\fP is missing, to the default list of probes.
94.TP
95.BR "-c, --client-sock=PATH"
96Specify path for the client unix socket
97.TP
98.BR "-a, --apps-sock PATH"
99Specify path for apps unix socket
100.TP
101.BR " --kconsumerd-err-sock=PATH"
102Specify path for the kernel consumer error socket
103.TP
104.BR " --kconsumerd-cmd-sock=PATH
105Specify path for the kernel consumer command socket
106.TP
107.BR " --ustconsumerd32-err-sock=PATH
108Specify path for the 32-bit UST consumer error socket
109.TP
110.BR " --ustconsumerd64-err-sock=PATH
111Specify path for the 64-bit UST consumer error socket
112.TP
113.BR " --ustconsumerd32-cmd-sock=PATH
114Specify path for the 32-bit UST consumer command socket
115.TP
116.BR " --ustconsumerd64-cmd-sock=PATH
117Specify path for the 64-bit UST consumer command socket
118.TP
119.BR " --consumerd32-path=PATH
120Specify path for the 32-bit UST consumer daemon binary
121.TP
122.BR " --consumerd32-libdir=PATH
123Specify path for the 32-bit UST consumer daemon libraries
124.TP
125.BR " --consumerd64-path=PATH
126Specify path for the 64-bit UST consumer daemon binary
127.TP
128.BR " --consumerd64-libdir=PATH
129Specify path for the 64-bit UST consumer daemon libraries
130.TP
131.BR "-l, --load PATH
132Specify path from which to automatically load session configuration(s).
133
134.SH "LOADING SESSIONS"
135
136.PP
137By default, the session daemon tries to load session configuration(s) located
138in the user default directory \fB~/.lttng/sessions/auto/\fP and in the system
139wide one in \fB/etc/lttng/sessions/auto/\fP. Note that the directory containing
140the session's configuration and lttng-sessiond MUST have the same UID for them
141to be automatically loaded.
142
143Specifying a path with \-l, \-\-load PATH overrides the default directory and
144UID check. The lttng-sessiond will simply check if it's accessible and try to
145load every session file in it.
146.PP
147
148.SH "ENVIRONMENT VARIABLES"
149
150.PP
151Note that all command line options will override environment variables.
152.PP
153
154.PP
155.IP "LTTNG_CONSUMERD32_BIN"
156Specify the 32-bit consumer binary path. \fB--consumerd32-path\fP
157override this variable.
158.IP "LTTNG_CONSUMERD64_BIN"
159Specify the 64-bit consumer binary path. \fB--consumerd64-path\fP
160override this variable.
161.IP "LTTNG_CONSUMERD32_LIBDIR"
162Specify the 64-bit library path containing libconsumer.so.
163\fB--consumerd32-libdir\fP override this variable.
164.IP "LTTNG_CONSUMERD64_LIBDIR"
165Specify the 32-bit library path containing libconsumer.so.
166\fB--consumerd64-libdir\fP override this variable.
167.IP "LTTNG_DEBUG_NOCLONE"
168Debug-mode disabling use of clone/fork. Insecure, but required to allow
169debuggers to work with sessiond on some operating systems.
170.IP "LTTNG_APP_SOCKET_TIMEOUT"
171Control the timeout of application's socket when sending and receiving
172commands. Takes an integer parameter: the timeout value, in seconds.
173After this period of time, the application is unregistered by the
174session daemon. A value of 0 or -1 means an infinite timeout. Default
175value is 5 seconds.
176.IP "LTTNG_NETWORK_SOCKET_TIMEOUT"
177Control timeout of socket connection, receive and send. Takes an integer
178parameter: the timeout value, in milliseconds. A value of 0 or -1 uses
179the timeout of the operating system (this is the default).
180.IP "LTTNG_SESSION_CONFIG_XSD_PATH"
181Specify the path that contains the XML session configuration schema (xsd).
182.IP "LTTNG_KMOD_PROBES"
183Specify the kernel modules probes that should be loaded by the session daemon.
184.IP "LTTNG_EXTRA_KMOD_PROBES"
185Specify extra kernel modules probes that should be loaded by the session daemon.
186.SH "SEE ALSO"
187
188.PP
189babeltrace(1), lttng-ust(3), lttng(1)
190.PP
191
192.SH "LIMITATIONS"
193
194.PP
195For unprivileged user running lttng-sessiond, the maximum number of file
196descriptors per process is usually 1024. This limits the number of traceable
197applications since for each instrumented application there is two file
198descriptors per-CPU and one more socket for bidirectional communication.
199
200For the root user, the limit is bumped to 65535. Future version will deal with
201this limitation.
202.PP
203
204.SH "BUGS"
205
206.PP
207No show stopper bugs are known yet in this version.
208
209If you encounter any issues or usability problem, please report it on our
210mailing list <lttng-dev@lists.lttng.org> to help improve this project.
211.SH "CREDITS"
212
213.PP
214lttng-sessiond is distributed under the GNU General Public License version 2. See the
215file COPYING for details.
216.PP
217A Web site is available at http://lttng.org for more information on the LTTng
218project.
219.PP
220You can also find our git tree at http://git.lttng.org.
221.PP
222Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
223.PP
224You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
225.PP
226.SH "THANKS"
227
228.PP
229Thanks to Yannick Brosseau without whom this project would never have been so
230lean and mean! Also thanks to the Ericsson teams working on tracing which helped
231us greatly with detailed bug reports and unusual test cases.
232
233Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
234maintainer) and Jon Bernard for our Debian packages.
235
236Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
237Montreal for the LTTng journey.
238.PP
239.SH "AUTHORS"
240
241.PP
242lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
243David Goulet. More people have since contributed to it. It is currently
244maintained by Jérémie Galarneau <jeremie.galarneau@efficios.com>.
245.PP
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