Kernel ftrace to CTF converter

This repository contains two components:

• a Babeltrace2 plugin to read trace-cmd's trace.dat file
• a program to convert the trace.dat into an LTTng (alike) kernel trace in CTF format

Note: The project is still in a very early state. Expect things to break!

Babeltrace2 Plugin (ftrace)

The plugin provides two components:

• source.ftrace.tracedat: read a trace.dat file
• sink.ftrace.tracemeta: emit clock definitions in JSON format for any stream begin message

Plugin source.ftrace.tracedat

The plugin uses the following initialization parameters:

• "inputs": array of string, mandatory: providing exactly one input file path
• "lttng": boolean, optional: indicating if LTTng semantics shall be used
• "clock-offset": uint64, optional: trace clock offset from world clock in ns
• "clock-uid": string, optional: UID or UUID of the trace clock
• "trace-name": string, optional: trace name and env.trace_name property
• "trace-creation-datetime": string (ISO‑8601), optional: env.trace_creation_datetime property

The plugin further implements the following query interfaces:

• babeltrace.support-info
• babeltrace.trace-infos

Example:

trace-cmd record -C mono -e "sched:sched_switch" sleep 1
babeltrace2 --plugin-path=. trace.dat

Plugin sink.ftrace.tracemeta

This plugin allows to gather information about trace clocks of a stream. The gathered data is written as JSON output either to standard out (default) or to a user-provided file descriptor. The output format is in json lines, whereby each object is as following:

{
  trace: { (uid: <str> | uuid: <str>)? },
  stream: { id: <int>, name: <str>},
  clock: { offset_s: <int>, offset_c: <int>, frequency: <int>, (uid: str | uuid: str)? },
  env: { { name: value }, ... }
}

The plugin uses the following initialization parameters:

• "outfd": int, optional: file descriptor to write output data to

Example:

babeltrace2 --plugin-path=. --component=meta:sink.ftrace.tracemeta /path/to/lttng-us/trace

trace.dat to CTF LTTng CTF converter

The converter uses libbabeltrace2 and the ftrace plugin to perform the conversion. The resulting trace can be opened with tracecompass as LTTng kernel trace.

Example:

export BABELTRACE_PLUGIN_PATH=$(pwd)
./ftrace-to-ctf --lttng trace.dat /tmp/traceout
# combine an ftrace with a LTTng US trace
./ftrace-to-ctf --lttng trace.dat /path/to/lttng-us/trace /tmp/traceout

Licenses

The babeltrace2 plugin is licensed under the LGPL-2.1-or-newer license, the converter is licensed under MIT. All source and header files provide SPDX headers.

Maintainers

• Felix Moessbauer [email protected]