| 1 | lttng-regenerate(1) |
| 2 | =================== |
| 3 | :revdate: 30 April 2021 |
| 4 | |
| 5 | |
| 6 | NAME |
| 7 | ---- |
| 8 | lttng-regenerate - Regenerate specific data of an LTTng tracing session |
| 9 | |
| 10 | |
| 11 | SYNOPSIS |
| 12 | -------- |
| 13 | Regenerate the metadata of a tracing session: |
| 14 | |
| 15 | [verse] |
| 16 | *lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *regenerate metadata* [option:--session='SESSION'] |
| 17 | |
| 18 | Regenerate the state dump event records of a tracing session: |
| 19 | |
| 20 | [verse] |
| 21 | *lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *regenerate statedump* [option:--session='SESSION'] |
| 22 | |
| 23 | |
| 24 | DESCRIPTION |
| 25 | ----------- |
| 26 | The `lttng regenerate` command regenerates specific data of: |
| 27 | |
| 28 | With the option:--session='SESSION' option:: |
| 29 | The tracing session named 'SESSION'. |
| 30 | |
| 31 | Without the option:--session option:: |
| 32 | The current tracing session (see man:lttng-concepts(7) to learn more |
| 33 | about the current tracing session). |
| 34 | |
| 35 | See man:lttng-concepts(7) to learn more about tracing sessions. |
| 36 | |
| 37 | As of this version, the `metadata` and `statedump` targets are |
| 38 | available. |
| 39 | |
| 40 | |
| 41 | Regenerate the metadata of a tracing session |
| 42 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 43 | Use the `metadata` target to resample the offset between the monotonic |
| 44 | clock and the wall time of the system, and then regenerate the metadata |
| 45 | stream files. |
| 46 | |
| 47 | More specifically, you may want to resample the wall time |
| 48 | following a major |
| 49 | link:https://en.wikipedia.org/wiki/Network_Time_Protocol[NTP] |
| 50 | correction. As such, LTTng can trace a system booting with an incorrect |
| 51 | wall time before its wall time is NTP-corrected. Regenerating the |
| 52 | metadata of the selected tracing session ensures that trace readers can |
| 53 | accurately determine the event record timestamps relative to the |
| 54 | Unix epoch. |
| 55 | |
| 56 | Note that if you plan to rotate (see man:lttng-concepts(7) to learn |
| 57 | more) the selected tracing session, this target only regenerates the |
| 58 | metadata stream files of the current and next trace chunks. |
| 59 | |
| 60 | [IMPORTANT] |
| 61 | ==== |
| 62 | You can only use the `metadata` target when the selected |
| 63 | tracing session: |
| 64 | |
| 65 | * Is not in live mode (nloption:--live option of |
| 66 | man:lttng-create(1)). |
| 67 | |
| 68 | * If it has user space channels, they're configured to use a |
| 69 | per-user buffering scheme (nloption:--buffers-uid option of |
| 70 | man:lttng-enable-channel(1)). |
| 71 | + |
| 72 | See man:lttng-concepts(7) to learn more about channels. |
| 73 | ==== |
| 74 | |
| 75 | |
| 76 | Regenerate the state dump event records of a tracing session |
| 77 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 78 | Use the `statedump` target to collect up-to-date state dump information |
| 79 | and create corresponding event records. |
| 80 | |
| 81 | This is particularly useful if the selected tracing session is in |
| 82 | snapshot mode (nloption:--snapshot option of the man:lttng-create(1) |
| 83 | command) or if LTTng rotates trace files for one of its channels (see |
| 84 | man:lttng-concepts(7)): in both cases, the state dump information may be |
| 85 | lost. |
| 86 | |
| 87 | |
| 88 | include::common-cmd-options-head.txt[] |
| 89 | |
| 90 | |
| 91 | option:-s 'SESSION', option:--session='SESSION':: |
| 92 | Regenerate specific data of the tracing session named 'SESSION' |
| 93 | instead of the current tracing session. |
| 94 | |
| 95 | |
| 96 | include::common-cmd-help-options.txt[] |
| 97 | |
| 98 | |
| 99 | include::common-cmd-footer.txt[] |
| 100 | |
| 101 | |
| 102 | SEE ALSO |
| 103 | -------- |
| 104 | man:lttng(1), |
| 105 | man:lttng-concepts(7) |