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[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 "-g, --group=NAME"
60Specify the tracing group name. (default: tracing)
61.TP
62.BR "-V, --version"
63Show version number
64.TP
65.BR "-S, --sig-parent"
66Send SIGUSR1 to parent pid to notify readiness.
67
68This is used by \fBlttng(1)\fP to get notified when the session daemon is ready
69to accept command. When building a third party tool over liblttng-ctl, this option
70can be very handy to synchronize the control tool and the session daemon.
71.TP
72.BR "-q, --quiet"
73No output at all.
74.TP
75.BR " --no-kernel"
76No kernel tracer support
77.TP
78.BR "-c, --client-sock=PATH"
79Specify path for the client unix socket
80.TP
81.BR "-a, --apps-sock PATH"
82Specify path for apps unix socket
83.TP
84.BR " --kconsumerd-err-sock=PATH"
85Specify path for the kernel consumer error socket
86.TP
87.BR " --kconsumerd-cmd-sock=PATH
88Specify path for the kernel consumer command socket
89.TP
90.BR " --ustconsumerd32-err-sock=PATH
91Specify path for the 32-bit UST consumer error socket
92.TP
93.BR " --ustconsumerd64-err-sock=PATH
94Specify path for the 64-bit UST consumer error socket
95.TP
96.BR " --ustconsumerd32-cmd-sock=PATH
97Specify path for the 32-bit UST consumer command socket
98.TP
99.BR " --ustconsumerd64-cmd-sock=PATH
100Specify path for the 64-bit UST consumer command socket
101.TP
102.BR " --consumerd32-path=PATH
103Specify path for the 32-bit UST consumer daemon binary
104.TP
105.BR " --consumerd32-libdir=PATH
106Specify path for the 32-bit UST consumer daemon libraries
107.TP
108.BR " --consumerd64-path=PATH
109Specify path for the 64-bit UST consumer daemon binary
110.TP
111.BR " --consumerd64-libdir=PATH
112Specify path for the 64-bit UST consumer daemon libraries
113.SH "ENVIRONMENT VARIABLES"
114
115.PP
116Note that all command line options will override environment variables.
117.PP
118
119.PP
120.IP "LTTNG_CONSUMERD32_BIN"
121Specify the 32-bit consumer binary path. \fB--consumerd32-path\fP
122override this variable.
123.IP "LTTNG_CONSUMERD64_BIN"
124Specify the 64-bit consumer binary path. \fB--consumerd64-path\fP
125override this variable.
126.IP "LTTNG_CONSUMERD32_LIBDIR"
127Specifiy the 64-bit library path containing libconsumer.so.
128\fB--consumerd32-libdir\fP override this variable.
129.IP "LTTNG_CONSUMERD64_LIBDIR"
130Specifiy the 32-bit library path containing libconsumer.so.
131\fB--consumerd64-libdir\fP override this variable.
132.IP "LTTNG_DEBUG_NOCLONE"
133Debug-mode disabling use of clone/fork. Insecure, but required to allow
134debuggers to work with sessiond on some operating systems.
135.IP "LTTNG_APP_SOCKET_TIMEOUT"
136Control the timeout of application's socket when sending and receiving
137commands. Takes an integer parameter: the timeout value, in seconds.
138After this period of time, the application is unregistered by the
139session daemon. A value of 0 or -1 means an infinite timeout. Default
140value is 5 seconds.
141.IP "LTTNG_NETWORK_SOCKET_TIMEOUT"
142Control timeout of socket connection, receive and send. Takes an integer
143parameter: the timeout value, in milliseconds. A value of 0 or -1 uses
144the timeout of the operating system (this is the default).
145.SH "SEE ALSO"
146
147.PP
148babeltrace(1), lttng-ust(3), lttng(1)
149.PP
150
151.SH "LIMITATIONS"
152
153.PP
154For unprivileged user running lttng-sessiond, the maximum number of file
155descriptors per process is usually 1024. This limits the number of traceable
156applications since for each instrumented application there is two file
157descriptors per-CPU and one more socktet for bidirectional communication.
158
159For the root user, the limit is bumped to 65535. Future version will deal with
160this limitation.
161.PP
162
163.SH "BUGS"
164
165.PP
166No show stopper bugs are known yet in this version.
167
168If you encounter any issues or usability problem, please report it on our
169mailing list <lttng-dev@lists.lttng.org> to help improve this project.
170.SH "CREDITS"
171
172.PP
173lttng-sessiond is distributed under the GNU General Public License version 2. See the
174file COPYING for details.
175.PP
176A Web site is available at http://lttng.org for more information on the LTTng
177project.
178.PP
179You can also find our git tree at http://git.lttng.org.
180.PP
181Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
182.PP
183You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
184.PP
185.SH "THANKS"
186
187.PP
188Thanks to Yannick Brosseau without whom this project would never have been so
189lean and mean! Also thanks to the Ericsson teams working on tracing which helped
190us greatly with detailed bug reports and unusual test cases.
191
192Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
193maintainer) and Jon Bernard for our Debian packages.
194
195Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
196Montreal for the LTTng journey.
197.PP
198.SH "AUTHORS"
199
200.PP
201lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
202David Goulet. More people have since contributed to it. It is currently
203maintained by David Goulet <dgoulet@efficios.com>.
204.PP
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