TRACE-CMD-SPLIT(1)

📦
version 3.4 · 13 versions
, in arch rolling

🦋 trace-cmd-split — like, the libtracefs manual, but make it make sense 💅

okay bestie, so this is trace-cmd-split(1) from the libtracefs Manual and honestly? it's kind of a legend. it takes one big trace.dat and chops it into cute little baby files. slay. ✨

🌸 SYNOPSIS 🌸

trace-cmd split [OPTIONS] [start-time [end-time]]

💖 DESCRIPTION 💖

so trace-cmd(1) split is literally the "break up a trace.dat into small files" girlie. that's her whole thing. 🎀

start-time is where the new file starts — like, where the party begins. pro tip: you can run trace-cmd-report(1), copy the timestamp sitting next to a particular event, and use that as input for either start-time or end-time. iykyk. 🫶

the split stops making files when it hits an event after end-time. and if you only need end-time? just use 0.0 as your start-time. easy.

if start-time is left out, the split starts at the beginning of the file. no notes. if end-time is left out, the split just keeps going until the end of the file — unless it runs into one of the requirements the options set up. 🦋

✨ OPTIONS ✨

  • -i file — if you don't pass this, the split command goes looking for a file named trace.dat (default behaviour, very main character). this option lets you read a different file instead of trace.dat.
  • -o file — by default the split command uses the input file name as the basis for where to write the split files. the output file is the input file with an attached '.#\' on the end: trace.dat.1, trace.dat.2, etc.

this option changes the name of the base file used.

-o file creates file.1, file.2, etc.

  • -s seconds — how many seconds should be recorded before the new file should stop.
  • -m milliseconds — how many milliseconds should be recorded before the new file should stop.
  • -u microseconds — how many microseconds should be recorded before the new file should stop.
  • -e events — how many events should be recorded before the new file should stop.
  • -p pages — the number of pages that should be recorded before the new file should stop.
⚠️ note: only one of -p, -e, -u, -m, -s may be specified at a time. pick one, bestie, you can't have all five. 🙈
💡 if -p is specified, then -c is automatically set. it just happens. no cap.
  • -r — this one causes the break up to repeat until end-time is reached (or end of the input, if you didn't give an end-time).
trace-cmd split -r -e 10000

this breaks trace.dat into several smaller files, each with at most 10,000 events in it. obsessed. 🔥

  • -c — this causes the above break up to be per CPU. iconic behaviour tbh.
trace-cmd split -c -p 10

this creates a file that has 10 pages per each CPU from the input.

  • -C cpu — this splits for a single CPU. only the cpu you name gets extracted from the file.
trace-cmd split -C 1

this splits out all the events for cpu 1 in the file. 🧚

  • --top — this allows you to keep the top buffer. the top buffer can be renamed using the -b option.
trace-cmd split --top

this keeps only the top buffer.

trace-cmd split --top -b old_top

this keeps only the top buffer and renames it 'old_top'. 💜

  • -B buffer — this allows you to keep the selected buffer. a buffer can be promoted to the top buffer using the -t option.
trace-cmd split -B timer -B sched

this keeps the 'timer' and 'sched' buffers.

trace-cmd split -B timer -t -B sched

this keeps the 'timer' and 'sched' buffers, with the events from the 'timer' buffer promoted to the top instance. 💫

🌈 SEE ALSO 🌈

trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-start(1), trace-cmd-stop(1), trace-cmd-extract(1), trace-cmd-reset(1), trace-cmd-list(1), trace-cmd-listen(1)

👑 AUTHOR 👑

written by Steven Rostedt, <rostedt@goodmis.org[1]> — yeah, that Steven Rostedt. respect the icon. 🫡

⭐ RESOURCES ⭐

https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/ — go look, it's giving open source excellence. 🦋

🍓 COPYING 🍓

Copyright (C) 2010 Red Hat, Inc. free use of this software is granted under the terms of the GNU Public License (GPL). periodt. 💅

📝 NOTES 📝

  1. rostedt@goodmis.org mailto:rostedt@goodmis.org

and that's the whole page, bestie! it's libtracefs, dated 03/09/2026 — saved you the scroll, you're welcome 💖✨🎀

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