1 .TH "LTTNG-SESSIOND" "8" "January 31, 2012" "" ""
4 lttng-sessiond \(em LTTng 2.x central tracing registry session daemon.
10 lttng-sessiond [OPTIONS]
15 The LTTng project aims at providing highly efficient tracing tools for Linux.
16 It's tracers help tracking down performance issues and debugging problems
17 involving multiple concurrent processes and threads. Tracing across multiple
18 systems is also possible.
20 The session daemon, acting as a tracing registry, allow you to interact with
21 multiple tracers (kernel and user-space) inside the same container, a tracing
22 session. 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
24 babeltrace(1) text viewer.
26 In order to trace the kernel, the session daemon needs to be running as root.
27 LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is
28 in that group can interact with the root session daemon and thus trace the
29 kernel. Session daemons can co-exist meaning that you can have a session daemon
30 running as Alice that can be used to trace her applications along side with a
31 root daemon or even a Bob daemon. We highly recommend to start the session
32 daemon at boot time for stable and long term tracing.
34 The session daemon is in charge of managing trace data consumers by spawning
35 them when the time has come. The user don't need to manage the lttng-consumerd.
39 This program follow the usual GNU command line syntax with long options starting with
40 two dashes. Below is a summary of the available options.
45 Show summary of possible options and commands
50 There is three debugging level which will print on stderr. Maximum verbosity is
53 .BR " --verbose-consumer"
54 Verbose mode for consumer. Activate DBG() macro.
59 .BR "-b, --background"
60 Start as a daemon, keeping console open
62 .BR "-g, --group=NAME"
63 Specify the tracing group name. (default: tracing)
68 .BR "-S, --sig-parent"
69 Send SIGUSR1 to parent pid to notify readiness.
71 This is used by \fBlttng(1)\fP to get notified when the session daemon is ready
72 to accept command. When building a third party tool over liblttng-ctl, this option
73 can be very handy to synchronize the control tool and the session daemon.
79 No kernel tracer support
81 .BR "-c, --client-sock=PATH"
82 Specify path for the client unix socket
84 .BR "-a, --apps-sock PATH"
85 Specify path for apps unix socket
87 .BR " --kconsumerd-err-sock=PATH"
88 Specify path for the kernel consumer error socket
90 .BR " --kconsumerd-cmd-sock=PATH
91 Specify path for the kernel consumer command socket
93 .BR " --ustconsumerd32-err-sock=PATH
94 Specify path for the 32-bit UST consumer error socket
96 .BR " --ustconsumerd64-err-sock=PATH
97 Specify path for the 64-bit UST consumer error socket
99 .BR " --ustconsumerd32-cmd-sock=PATH
100 Specify path for the 32-bit UST consumer command socket
102 .BR " --ustconsumerd64-cmd-sock=PATH
103 Specify path for the 64-bit UST consumer command socket
105 .BR " --consumerd32-path=PATH
106 Specify path for the 32-bit UST consumer daemon binary
108 .BR " --consumerd32-libdir=PATH
109 Specify path for the 32-bit UST consumer daemon libraries
111 .BR " --consumerd64-path=PATH
112 Specify path for the 64-bit UST consumer daemon binary
114 .BR " --consumerd64-libdir=PATH
115 Specify path for the 64-bit UST consumer daemon libraries
116 .SH "ENVIRONMENT VARIABLES"
119 Note that all command line options will override environment variables.
123 .IP "LTTNG_CONSUMERD32_BIN"
124 Specify the 32-bit consumer binary path. \fB--consumerd32-path\fP
125 override this variable.
126 .IP "LTTNG_CONSUMERD64_BIN"
127 Specify the 64-bit consumer binary path. \fB--consumerd64-path\fP
128 override this variable.
129 .IP "LTTNG_CONSUMERD32_LIBDIR"
130 Specifiy the 64-bit library path containing libconsumer.so.
131 \fB--consumerd32-libdir\fP override this variable.
132 .IP "LTTNG_CONSUMERD64_LIBDIR"
133 Specifiy the 32-bit library path containing libconsumer.so.
134 \fB--consumerd64-libdir\fP override this variable.
135 .IP "LTTNG_DEBUG_NOCLONE"
136 Debug-mode disabling use of clone/fork. Insecure, but required to allow
137 debuggers to work with sessiond on some operating systems.
138 .IP "LTTNG_APP_SOCKET_TIMEOUT"
139 Control the timeout of application's socket when sending and receiving
140 commands. Takes an integer parameter: the timeout value, in seconds.
141 After this period of time, the application is unregistered by the
142 session daemon. A value of 0 or -1 means an infinite timeout. Default
144 .IP "LTTNG_NETWORK_SOCKET_TIMEOUT"
145 Control timeout of socket connection, receive and send. Takes an integer
146 parameter: the timeout value, in milliseconds. A value of 0 or -1 uses
147 the timeout of the operating system (this is the default).
151 babeltrace(1), lttng-ust(3), lttng(1)
157 For unprivileged user running lttng-sessiond, the maximum number of file
158 descriptors per process is usually 1024. This limits the number of traceable
159 applications since for each instrumented application there is two file
160 descriptors per-CPU and one more socktet for bidirectional communication.
162 For the root user, the limit is bumped to 65535. Future version will deal with
169 No show stopper bugs are known yet in this version.
171 If you encounter any issues or usability problem, please report it on our
172 mailing list <lttng-dev@lists.lttng.org> to help improve this project.
176 lttng-sessiond is distributed under the GNU General Public License version 2. See the
177 file COPYING for details.
179 A Web site is available at http://lttng.org for more information on the LTTng
182 You can also find our git tree at http://git.lttng.org.
184 Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
186 You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
191 Thanks to Yannick Brosseau without whom this project would never have been so
192 lean and mean! Also thanks to the Ericsson teams working on tracing which helped
193 us greatly with detailed bug reports and unusual test cases.
195 Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
196 maintainer) and Jon Bernard for our Debian packages.
198 Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
199 Montreal for the LTTng journey.
204 lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
205 David Goulet. More people have since contributed to it. It is currently
206 maintained by David Goulet <dgoulet@efficios.com>.