LTTNG-REGENERATE(1)

📦
version 2.15.1 · 12 versions
, in ubuntu stonking

✨ lttng-regenerate — regenerating your session's data, but make it fashion ✨

okay bestie so this is a page from the LTTng Manual about the lttng-regenerate command, and it's literally the glow-up button for specific data inside an LTTng recording session. sit down, drink your iced coffee, let's get into it 💅

🌸 NAME 🌸

lttng-regenerate — Regenerate specific data of an LTTng recording session

🎀 SYNOPSIS 🎀

Regenerate the metadata of a recording session:

lttng [GENERAL OPTIONS] regenerate metadata [--session=SESSION]

Regenerate the state dump event records of a recording session:

lttng [GENERAL OPTIONS] regenerate statedump [--session=SESSION]

🦋 DESCRIPTION 🦋

The lttng regenerate command regenerates specific data of:

  • With the --session=SESSION option The recording session named SESSION.
  • Without the --session option The current recording session (see lttng-concepts(7) to learn more about the current recording session).

See lttng-concepts(7) to learn more about recording sessions.

As of this version, the metadata and statedump targets are available. that's it, that's the lineup 👑

See the “EXAMPLES” section below for usage examples.

🧚 Regenerate the metadata of a recording session 🧚

Use the metadata target to resample the offset between the monotonic clock and the wall time of the system, and then regenerate the metadata stream files.

More specifically, you may want to resample the wall time following a major NTP <https://en.wikipedia.org/wiki/Network_Time_Protocol> correction. As such, LTTng can trace a system booting with an incorrect wall time before its wall time is NTP-corrected. Regenerating the metadata of the selected recording session ensures that trace readers can accurately determine the event record timestamps relative to the Unix epoch.

Note that if you plan to rotate (see lttng-concepts(7) to learn more) the selected recording session, this target only regenerates the metadata stream files of the current and next trace chunks. so not everything, just the current and next ones, no cap 👀

Important 💀 You can only use the metadata target when the selected recording session satisfies all of the following conditions: - Is not in live mode (--live option of lttng-create(1)). - If it has user space channels, they’re configured to use a per-user buffer ownership model (--buffer-ownership=user option of lttng-enable-channel(1)). See lttng-concepts(7) to learn more about channels.

🌈 Regenerate the state dump event records of a recording session 🌈

Use the statedump target to collect up-to-date state dump information and create corresponding event records.

This is particularly useful if the selected recording session is in snapshot mode (--snapshot option of the lttng-create(1) command) or if LTTng rotates trace files for one of its channels (see lttng-concepts(7)): in both cases, the state dump information may be lost. and losing your state dump info? not the vibe at all 😭

💖 OPTIONS 💖

See lttng(1) for GENERAL OPTIONS.

  • -s SESSION, --session=SESSION — Regenerate specific data of the recording session named SESSION instead of the current recording session. like, pick your fave instead of going with the default 🫶

⭐ Program information ⭐

  • -h, --help — Show help.

This option attempts to launch /usr/bin/man to view this manual page. Override the manual pager path with the LTTNG_MAN_BIN_PATH environment variable.

  • --list-options — List available command options and quit.

🔥 EXIT STATUS 🔥

  • 0 — Success ✨
  • 1 — Command error 😬
  • 2 — Undefined command 🤨
  • 3 — Fatal error 💀
  • 4 — Command warning (something went wrong during the command) 🙈

🌸 ENVIRONMENT 🌸

  • LTTNG_ABORT_ON_ERROR — Set to 1 to abort the process after the first error is encountered.
  • LTTNG_HOME — Path to the LTTng home directory.

Defaults to $HOME.

Useful when the Unix user running the commands has a non-writable home directory.

  • LTTNG_LIST_LEGACY — Set to 1 to use the legacy output format (LTTng 2.14 and earlier) for the lttng-list(1) command instead of the modern output format.

Note that the legacy output doesn’t show anything related to features introduced after LTTng 2.14.

  • LTTNG_MAN_BIN_PATH — Absolute path to the manual pager to use to read the LTTng command-line help (with lttng-help(1) or with the --help option) instead of /usr/bin/man.
  • LTTNG_NO_UTF_8 — Set to 1 to NOT emit multi-byte UTF-8 sequences, even if the locale claims to support it.
  • LTTNG_SESSION_CONFIG_XSD_PATH — Path to the directory containing the session.xsd recording session configuration XML schema.
  • LTTNG_SESSIOND_PATH — Absolute path to the LTTng session daemon binary (see lttng-sessiond(8)) to spawn from the lttng-create(1) command.

The --sessiond-path general option overrides this environment variable.

  • LTTNG_TERM_COLOR — Controls when to emit terminal SGR codes in the output.

The NO_COLOR environment variable overrides this.

One of:

  • auto (default) Only emit SGR codes when the standard output is connected to a color-capable terminal.
  • always Always emit SGR codes.
  • never Never emit SGR codes.
  • NO_COLOR — If set and not empty, then it’s equivalent to setting LTTNG_TERM_COLOR to never.

See NO_COLOR <https://no-color.org/> to learn more.

🎀 FILES 🎀

  • $LTTNG_HOME/.lttngrc — Unix user’s LTTng runtime configuration.

This is where LTTng stores the name of the Unix user’s current recording session between executions of lttng(1). lttng-create(1) and lttng-set-session(1) set the current recording session.

  • $LTTNG_HOME/lttng-traces — Default output directory of LTTng traces in local and snapshot modes.

Override this path with the --output option of the lttng-create(1) command.

  • $LTTNG_HOME/.lttng — Unix user’s LTTng runtime and configuration directory.
  • $LTTNG_HOME/.lttng/sessions — Default directory containing the Unix user’s saved recording session configurations (see lttng-save(1) and lttng-load(1)).
  • /etc/lttng/sessions — Directory containing the system-wide saved recording session configurations (see lttng-save(1) and lttng-load(1)).
Note 🫶 $LTTNG_HOME defaults to the value of the HOME environment variable.

🦋 EXAMPLES 🦋

Example 1. Regenerate the metadata of the current recording session.

$ lttng regenerate metadata

Example 2. Regenerate the state dump event records of a specific recording session.

See the --session option.

$ lttng regenerate statedump --session=my-session

👑 RESOURCES 👑

This program is part of the LTTng-tools project.

LTTng-tools is distributed under the GNU General Public License version 2 <http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html>. See the LICENSE <https://github.com/lttng/lttng-tools/blob/master/LICENSE> file for details.

🌈 THANKS 🌈

Special thanks to Michel Dagenais and the DORSAL laboratory <http://www.dorsal.polymtl.ca/> at École Polytechnique de Montréal for the LTTng journey.

Also thanks to the Ericsson teams working on tracing which helped us greatly with detailed bug reports and unusual test cases.

⭐ SEE ALSO ⭐

lttng(1), lttng-concepts(7)

and that's the whole page bestie 💅 fr fr, this is lttng-regenerate from the LTTng 2.15.1 manual, dated 14 June 2021 — periodt, go regenerate something iconic 🎀✨

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