| 1 | lttng-regenerate(1) |
| 2 | =================== |
| 3 | :revdate: 17 May 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 | See the <<examples,EXAMPLES>> section below for usage examples. |
| 41 | |
| 42 | |
| 43 | Regenerate the metadata of a tracing session |
| 44 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 45 | Use the `metadata` target to resample the offset between the monotonic |
| 46 | clock and the wall time of the system, and then regenerate the metadata |
| 47 | stream files. |
| 48 | |
| 49 | More specifically, you may want to resample the wall time |
| 50 | following a major |
| 51 | link:https://en.wikipedia.org/wiki/Network_Time_Protocol[NTP] |
| 52 | correction. As such, LTTng can trace a system booting with an incorrect |
| 53 | wall time before its wall time is NTP-corrected. Regenerating the |
| 54 | metadata of the selected tracing session ensures that trace readers can |
| 55 | accurately determine the event record timestamps relative to the |
| 56 | Unix epoch. |
| 57 | |
| 58 | Note that if you plan to rotate (see man:lttng-concepts(7) to learn |
| 59 | more) the selected tracing session, this target only regenerates the |
| 60 | metadata stream files of the current and next trace chunks. |
| 61 | |
| 62 | [IMPORTANT] |
| 63 | ==== |
| 64 | You can only use the `metadata` target when the selected |
| 65 | tracing session: |
| 66 | |
| 67 | * Is not in live mode (nloption:--live option of |
| 68 | man:lttng-create(1)). |
| 69 | |
| 70 | * If it has user space channels, they're configured to use a |
| 71 | per-user buffering scheme (nloption:--buffers-uid option of |
| 72 | man:lttng-enable-channel(1)). |
| 73 | + |
| 74 | See man:lttng-concepts(7) to learn more about channels. |
| 75 | ==== |
| 76 | |
| 77 | |
| 78 | Regenerate the state dump event records of a tracing session |
| 79 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 80 | Use the `statedump` target to collect up-to-date state dump information |
| 81 | and create corresponding event records. |
| 82 | |
| 83 | This is particularly useful if the selected tracing session is in |
| 84 | snapshot mode (nloption:--snapshot option of the man:lttng-create(1) |
| 85 | command) or if LTTng rotates trace files for one of its channels (see |
| 86 | man:lttng-concepts(7)): in both cases, the state dump information may be |
| 87 | lost. |
| 88 | |
| 89 | |
| 90 | include::common-lttng-cmd-options-head.txt[] |
| 91 | |
| 92 | |
| 93 | option:-s 'SESSION', option:--session='SESSION':: |
| 94 | Regenerate specific data of the tracing session named 'SESSION' |
| 95 | instead of the current tracing session. |
| 96 | |
| 97 | |
| 98 | include::common-lttng-cmd-help-options.txt[] |
| 99 | |
| 100 | |
| 101 | include::common-lttng-cmd-after-options.txt[] |
| 102 | |
| 103 | |
| 104 | [[examples]] |
| 105 | EXAMPLES |
| 106 | -------- |
| 107 | .Regenerate the metadata of the current tracing session. |
| 108 | ==== |
| 109 | [role="term"] |
| 110 | ---- |
| 111 | $ lttng regenerate metadata |
| 112 | ---- |
| 113 | ==== |
| 114 | |
| 115 | .Regenerate the state dump event records of a specific tracing session. |
| 116 | ==== |
| 117 | See the option:--session option. |
| 118 | |
| 119 | [role="term"] |
| 120 | ---- |
| 121 | $ lttng regenerate statedump --session=my-session |
| 122 | ---- |
| 123 | ==== |
| 124 | |
| 125 | |
| 126 | include::common-footer.txt[] |
| 127 | |
| 128 | |
| 129 | SEE ALSO |
| 130 | -------- |
| 131 | man:lttng(1), |
| 132 | man:lttng-concepts(7) |