| 1 | --- |
| 2 | id: lttng-modules |
| 3 | --- |
| 4 | |
| 5 | The LTTng Linux kernel modules provide everything needed to trace the |
| 6 | Linux kernel: various probes, a ring buffer implementation for a |
| 7 | consumer daemon to read trace data and the tracer itself. |
| 8 | |
| 9 | Only in exceptional circumstances should you ever need to load the |
| 10 | LTTng kernel modules manually: it is normally the responsability of |
| 11 | `root`'s session daemon to do so. Even if you were to develop your |
| 12 | own LTTng probe module—for tracing a custom kernel or some kernel |
| 13 | module (this topic is covered in the |
| 14 | [Linux kernel](#doc-instrumenting-linux-kernel) instrumenting guide of |
| 15 | the [Using LTTng](#doc-using-lttng) chapter)—you |
| 16 | should use the `--extra-kmod-probes` option of the session daemon to |
| 17 | append your probe to the default list. The session and consumer daemons |
| 18 | of regular users do not interact with the LTTng kernel modules at all. |
| 19 | |
| 20 | LTTng kernel modules are installed, by default, in |
| 21 | <code>/usr/lib/modules/<em>release</em>/extra</code>, where |
| 22 | <code><em>release</em></code> is the kernel release |
| 23 | (see `uname --kernel-release`). |