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5e0cbfb0 PP |
1 | --- |
2 | id: saving-loading-tracing-session | |
3 | --- | |
4 | ||
5 | Configuring a tracing session may be long: creating and enabling | |
6 | channels with specific parameters, enabling kernel and user space | |
7 | domain events with specific log levels and filters, adding context | |
8 | to some channels, etc. If you're going to use LTTng to solve real | |
9 | world problems, chances are you're going to have to record events using | |
10 | the same tracing session setup over and over, modifying a few variables | |
11 | each time in your instrumented program or environment. To avoid | |
12 | constant tracing session reconfiguration, the `lttng` tool is able to | |
13 | save and load tracing session configurations to/from XML files. | |
14 | ||
15 | To save a given tracing session configuration, do: | |
16 | ||
17 | <pre class="term"> | |
18 | lttng save my-session | |
19 | </pre> | |
20 | ||
21 | where `my-session` is the name of the tracing session to save. Tracing | |
22 | session configurations are saved to `~/.lttng/sessions` by default; | |
23 | use the `--output-path` option to change this destination directory. | |
24 | ||
25 | All configuration parameters are saved: | |
26 | ||
27 | * tracing session name | |
28 | * trace data output path | |
29 | * channels with their state and all their parameters | |
30 | * context information added to channels | |
31 | * events with their state, log level and filter | |
32 | * tracing activity (started or stopped) | |
33 | ||
34 | To load a tracing session, simply do: | |
35 | ||
36 | <pre class="term"> | |
37 | lttng load my-session | |
38 | </pre> | |
39 | ||
40 | or, if you used a custom path: | |
41 | ||
42 | <pre class="term"> | |
43 | lttng load --input-path /path/to/my-session.lttng | |
44 | </pre> | |
45 | ||
47bfcb75 | 46 | Your saved tracing session is restored as if you just configured |
5e0cbfb0 | 47 | it manually. |