contents/using-lttng/controlling-tracing/intro.md

   1 ---
   2 id: controlling-tracing
   3 ---
   4
   5 Once you're in possession of a software that is properly
   6 [instrumented](#doc-instrumenting) for LTTng tracing, be it thanks to
   7 the built-in LTTng probes for the Linux kernel, a custom user
   8 application, or a custom Linux kernel, all that is left is actually
   9 tracing it.
  10
  11 You control LTTng tracing using a single command
  12 line tool: `lttng`. LTTng [session daemons](#doc-lttng-sessiond) may
  13 either be started manually (`lttng-sessiond`) or automatically by the
  14 `lttng` command when a sessions is created. Trace data may be forwarded
  15 to the network and used elsewhere using an LTTng
  16 [relay daemon](#doc-lttng-relayd) (`lttng-relayd`).
  17
  18 The man pages of `lttng`, `lttng-sessiond`, and `lttng-relayd` are pretty
  19 complete, thus this section is not an online copy of the latter (we
  20 leave this contents for the
  21 [Online LTTng man pages](#doc-online-lttng-manpages) section).
  22 This section is rather a tour of LTTng
  23 features through practical examples and tips.
  24
  25 If not already done, make sure you understand the core concepts
  26 and how LTTng components connect together by reading the
  27 [Understanding LTTng](#doc-understanding-lttng) chapter; this section
  28 assumes you are familiar with them.