contents/understanding-lttng/core-concepts/domain.md

   1 ---
   2 id: domain
   3 ---
   4
   5 A tracing _domain_ is the official term the LTTng project uses to
   6 designate a tracer category.
   7
   8 There are currently five known domains:
   9
  10   * Linux kernel
  11   * user space
  12   * `java.util.logging` (JUL)
  13   * log4j
  14   * Python (2 and 3 are supported)
  15
  16 Different tracers expose common features in their own interfaces, but,
  17 from a user's perspective, you still need to target a specific type of
  18 tracer to perform some actions. For example, since both kernel and user
  19 space tracers support named tracepoints (probes manually inserted in
  20 source code), you need to specify which one is concerned when enabling
  21 an event because both domains could have existing events with the same
  22 name.
  23
  24 Some features are reserved for some domains. Dynamic function entry/return
  25 instrumentation, for example, is currently only supported in the kernel
  26 domain, but support for other domains could be added in the future.