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eded6438 | 1 | lttng-regenerate(1) |
4605890e | 2 | =================== |
188419c4 | 3 | :revdate: 30 April 2021 |
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4 | |
5 | ||
6 | NAME | |
7 | ---- | |
188419c4 | 8 | lttng-regenerate - Regenerate specific data of an LTTng tracing session |
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9 | |
10 | ||
11 | SYNOPSIS | |
12 | -------- | |
188419c4 | 13 | Regenerate the metadata of a tracing session: |
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14 | |
15 | [verse] | |
16 | *lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *regenerate metadata* [option:--session='SESSION'] | |
17 | ||
188419c4 | 18 | Regenerate the state dump event records of a tracing session: |
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19 | |
20 | [verse] | |
21 | *lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *regenerate statedump* [option:--session='SESSION'] | |
22 | ||
188419c4 | 23 | |
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24 | DESCRIPTION |
25 | ----------- | |
188419c4 | 26 | The `lttng regenerate` command regenerates specific data of: |
dbcf3dd3 | 27 | |
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28 | With the option:--session='SESSION' option:: |
29 | The tracing session named 'SESSION'. | |
dbcf3dd3 | 30 | |
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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). | |
dbcf3dd3 | 34 | |
188419c4 | 35 | See man:lttng-concepts(7) to learn more about tracing sessions. |
eded6438 | 36 | |
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37 | As of this version, the `metadata` and `statedump` targets are |
38 | available. | |
980bb5fd | 39 | |
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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 | |
dbcf3dd3 | 85 | lost. |
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86 | |
87 | ||
55e06994 | 88 | include::common-lttng-cmd-options-head.txt[] |
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89 | |
90 | ||
59b19c3c | 91 | option:-s 'SESSION', option:--session='SESSION':: |
188419c4 | 92 | Regenerate specific data of the tracing session named 'SESSION' |
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93 | instead of the current tracing session. |
94 | ||
95 | ||
55e06994 | 96 | include::common-lttng-cmd-help-options.txt[] |
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97 | |
98 | ||
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99 | include::common-lttng-cmd-after-options.txt[] |
100 | ||
101 | ||
102 | include::common-footer.txt[] | |
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103 | |
104 | ||
105 | SEE ALSO | |
106 | -------- | |
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107 | man:lttng(1), |
108 | man:lttng-concepts(7) |