doc/man/lttng-sessiond.8

   1 .TH "LTTNG-SESSIOND" "8" "January 31, 2012" "" ""
   2
   3 .SH "NAME"
   4 lttng-sessiond \(em LTTng 2.x central tracing registry session daemon.
   5
   6 .SH "SYNOPSIS"
   7
   8 .PP
   9 .nf
  10 lttng-sessiond [OPTIONS]
  11 .fi
  12 .SH "DESCRIPTION"
  13
  14 .PP
  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.
  19
  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.
  25
  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.
  33
  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.
  36 .SH "OPTIONS"
  37
  38 .PP
  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.
  41 .PP
  42
  43 .TP
  44 .BR "-h, --help"
  45 Show summary of possible options and commands
  46 .TP
  47 .BR "-v, --verbose"
  48 Increase verbosity
  49
  50 There is three debugging level which will print on stderr. Maximum verbosity is
  51 \fB-vvv\fP.
  52 .TP
  53 .BR "    --verbose-consumer"
  54 Verbose mode for consumer. Activate DBG() macro.
  55 .TP
  56 .BR "-d, --daemonize"
  57 Start as a daemon
  58 .TP
  59 .BR "-g, --group=NAME"
  60 Specify the tracing group name. (default: tracing)
  61 .TP
  62 .BR "-V, --version"
  63 Show version number
  64 .TP
  65 .BR "-S, --sig-parent"
  66 Send SIGCHLD to parent pid to notify readiness.
  67
  68 This is used by \fBlttng(1)\fP to get notified when the session daemon is ready
  69 to accept command. When building a third party tool over liblttng-ctl, this option
  70 can be very handy to synchronize the control tool and the session daemon.
  71 .TP
  72 .BR "-q, --quiet"
  73 No output at all.
  74 .TP
  75 .BR "    --no-kernel"
  76 No kernel tracer support
  77 .TP
  78 .BR "-c, --client-sock=PATH"
  79 Specify path for the client unix socket
  80 .TP
  81 .BR "-a, --apps-sock PATH"
  82 Specify path for apps unix socket
  83 .TP
  84 .BR "    --kconsumerd-err-sock=PATH"
  85 Specify path for the kernel consumer error socket
  86 .TP
  87 .BR "    --kconsumerd-cmd-sock=PATH
  88 Specify path for the kernel consumer command socket
  89 .TP
  90 .BR "    --ustconsumerd32-err-sock=PATH
  91 Specify path for the 32-bit UST consumer error socket
  92 .TP
  93 .BR "    --ustconsumerd64-err-sock=PATH
  94 Specify path for the 64-bit UST consumer error socket
  95 .TP
  96 .BR "    --ustconsumerd32-cmd-sock=PATH
  97 Specify path for the 32-bit UST consumer command socket
  98 .TP
  99 .BR "    --ustconsumerd64-cmd-sock=PATH
 100 Specify path for the 64-bit UST consumer command socket
 101 .TP
 102 .BR "    --consumerd32-path=PATH
 103 Specify path for the 32-bit UST consumer daemon binary
 104 .TP
 105 .BR "    --consumerd32-libdir=PATH
 106 Specify path for the 32-bit UST consumer daemon libraries
 107 .TP
 108 .BR "    --consumerd64-path=PATH
 109 Specify path for the 64-bit UST consumer daemon binary
 110 .TP
 111 .BR "    --consumerd64-libdir=PATH
 112 Specify path for the 64-bit UST consumer daemon libraries
 113 .SH "ENVIRONMENT VARIABLES"
 114
 115 .PP
 116 Note that all command line options will override environment variables.
 117 .PP
 118
 119 .PP
 120 .IP "LTTNG_CONSUMERD32_BIN"
 121 Specify the 32-bit consumer binary path. \fB--consumerd32-path\fP
 122 override this variable.
 123 .IP "LTTNG_CONSUMERD64_BIN"
 124 Specify the 64-bit consumer binary path. \fB--consumerd64-path\fP
 125 override this variable.
 126 .IP "LTTNG_CONSUMERD32_LIBDIR"
 127 Specifiy the 64-bit library path containing libconsumer.so.
 128 \fB--consumerd32-libdir\fP override this variable.
 129 .IP "LTTNG_CONSUMERD64_LIBDIR"
 130 Specifiy the 32-bit library path containing libconsumer.so.
 131 \fB--consumerd64-libdir\fP override this variable.
 132 .IP "LTTNG_DEBUG_NOCLONE"
 133 Debug-mode disabling use of clone/fork. Insecure, but required to allow
 134 debuggers to work with sessiond on some operating systems.
 135 .IP "LTTNG_APP_SOCKET_TIMEOUT"
 136 Control the timeout of application's socket when sending and receiving
 137 commands. After this period of time, the application is unregistered by the
 138 session daemon. A value of 0 or -1 means an infinite timeout. Default value is
 139 5 seconds.
 140 .SH "SEE ALSO"
 141
 142 .PP
 143 babeltrace(1), lttng-ust(3), lttng(1)
 144 .PP
 145
 146 .SH "LIMITATIONS"
 147
 148 .PP
 149 For unprivileged user running lttng-sessiond, the maximum number of file
 150 descriptors per process is usually 1024. This limits the number of traceable
 151 applications since for each instrumented application there is two file
 152 descriptors per-CPU and one more socktet for bidirectional communication.
 153
 154 For the root user, the limit is bumped to 65535. Future version will deal with
 155 this limitation.
 156 .PP
 157
 158 .SH "BUGS"
 159
 160 .PP
 161 No show stopper bugs are known yet in this version.
 162
 163 If you encounter any issues or usability problem, please report it on our
 164 mailing list <lttng-dev@lists.lttng.org> to help improve this project.
 165 .SH "CREDITS"
 166
 167 .PP
 168 lttng-sessiond is distributed under the GNU General Public License version 2. See the
 169 file COPYING for details.
 170 .PP
 171 A Web site is available at http://lttng.org for more information on the LTTng
 172 project.
 173 .PP
 174 You can also find our git tree at http://git.lttng.org.
 175 .PP
 176 Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
 177 .PP
 178 You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
 179 .PP
 180 .SH "THANKS"
 181
 182 .PP
 183 Thanks to Yannick Brosseau without whom this project would never have been so
 184 lean and mean! Also thanks to the Ericsson teams working on tracing which helped
 185 us greatly with detailed bug reports and unusual test cases.
 186
 187 Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
 188 maintainer) and Jon Bernard for our Debian packages.
 189
 190 Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
 191 Montreal for the LTTng journey.
 192 .PP
 193 .SH "AUTHORS"
 194
 195 .PP
 196 lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
 197 David Goulet. More people have since contributed to it. It is currently
 198 maintained by David Goulet <dgoulet@efficios.com>.
 199 .PP