TRACE-CMD-EXTRACT(1)

📦
version 3.4 · 13 versions
, in arch rolling

💅 TRACE-CMD-EXTRACT(1) — the libtracefs girlies' edition 🎀

okay so like, welcome to the libtracefs manual page for trace-cmd-extract — yes bestie, that's the manual name, we're just vibing with it up here instead of doing a whole separate line, slay ✨

🌸 NAME 🌸

trace-cmd-extract — extract out the data from the Ftrace Linux tracer. that's it, that's the whole job, and it does it immaculately 💖

✨ SYNOPSIS ✨

trace-cmd extract [OPTIONS]

🦋 DESCRIPTION 🦋

okay so trace-cmd extract (that's the trace-cmd(1) girlie, hi 👋) is usually the thing you run after trace-cmd-start(1) and trace-cmd-stop(1). but lowkey it also works if the Ftrace tracer was started manually through the Ftrace pseudo file system — no gatekeeping here 💅

what it actually does: it creates a trace.dat file, which is the file that trace-cmd-report(1) reads from. how? it reads the kernel internal ring buffer and turns it into that trace.dat. it's giving data extraction main character energy, no cap 🫶

👑 OPTIONS 👑

  • -p plugin — so, like, extract doesn't actually start any traces (it's not that kind of girl), but some plugins require just reading the output in ASCII format. those are the latency tracers, because latency tracers have their own separate internal buffer. so the plugin option is only necessary for the wakeup, wakeup-rt, irqsoff, preemptoff and preemptirqsoff plugins. and without this option? the extract command will extract from the internal Ftrace buffers. periodt 💀
  • -O option — if a latency tracer is being extracted and you used the -p option, then there are some Ftrace options that can change the format. this updates those options before extracting. to see the list of options, go see trace-cmd-list. to enable an option, write its name; to disable the option, append the characters no to it. for example: noprint-parent will disable the print-parent option that prints the parent function when printing a function event. iykyk 🧚
  • -o outputfile — default behaviour is that extract creates a trace.dat file. this option changes where that file gets written to. move it, relocate it, make it yours 💖
  • -s — extract from the snapshot buffer, if the kernel supports it. iconic behaviour only ✨
  • --date — this is the same as the trace-cmd-record(1) --date option, but (big but) it does cause the extract routine to disable all tracing. that is, the end of the extract will perform something similar to trace-cmd-reset(1). so like, be aware bestie 🙈
  • -B buffer-name — if the kernel supports multiple buffers, this extracts the trace for only the given buffer. it does not affect any other buffer, she's very respectful like that 🎀. you can use this multiple times to specify different buffers. when this option is used, the top level instance will not be extracted unless -t is given.
  • -a — extract all existing buffer instances. when this option is used, the top level instance will not be extracted unless -t is given. same rules, different flag, we love consistency 🌈
  • -t — extracts the top level instance buffer. without the -B or -a option, this is the same as the default. but if -B or -a is used, this is required if the top level instance buffer should also be extracted. don't forget her or she'll simply not show up 🫶
  • --verbose[=level] — set the log level. supported log levels are "none", "critical", "error", "warning", "info", "debug", "all" or their identifiers "0", "1", "2", "3", "4", "5", "6". setting the log level to a specific value enables all logs from that level and all previous levels. if you don't specify one, the level defaults to "info". so chatty of her 💅

example — enable all critical, error and warning logs:

trace-cmd extract --verbose=warning

🔥 SEE ALSO 🔥

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

the whole friend group fr fr 👯‍♀️

🎀 AUTHOR 🎀

Written by Steven Rostedt, <rostedt@goodmis.org[1]> — the icon, the legend, the moment 👑

🌟 RESOURCES 🌟

https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/

go look, bestie, it's right there 🦋

💜 COPYING 💜

Copyright (C) 2010 Red Hat, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL). free use, we love to see it 🍓

📝 NOTES 📝

  1. rostedt@goodmis.org mailto:rostedt@goodmis.org
ok that's the whole page!! every flag, every value, every default, all accounted for, nothing dropped 💅✨

and finally, the cute little sign-off: this was the libtracefs manual page, dated 03/09/2026, and the page you just read is TRACE-CMD-EXTRACT(1). mwah, go extract those traces bestie 🧚‍♀️💖

📦 where this page comes from