trace-cmd-snapshot(1)

trace-cmd-snapshot1

Take, reset, free, or show a ftrace kernel snapshot

Usage

trace-cmd snapshot [OPTIONS]

Overview

The trace-cmd(1) snapshot controls or displays the Ftrace Linux kernel snapshot feature (if the kernel supports it). This is useful to "freeze" an instance of a live trace but without stopping the trace.

 trace-cmd start -p function
 trace-cmd snapshot -s
 trace-cmd snapshot
[ dumps the content of buffer at 'trace-cmd snapshot -s' ]
 trace-cmd snapshot -s
 trace-cmd snapshot
[ dumps the new content of the buffer at the last -s operation ]

Options

-s

Take a snapshot of the currently running buffer.

-r

Clear out the buffer.

-f

Free the snapshot buffer. The buffer takes up memory inside the kernel. It is best to free it when not in use. The first -s operation will allocate it if it is not already allocated.

-c cpu

Operate on a per cpu snapshot (may not be fully supported by all kernels)

-B buf

If a buffer instance was created, then the -B option will operate on the snapshot within the buffer.

Resources

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

Copying

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

Notes

Releases

7 releases since Debian 8 (Jessie); the text changed 6 times.

  1. 8
  2. 9
  3. 10
  4. 11
  5. 12
  6. 13
  7. Arch

Author

Written by Steven Rostedt, <[email protected][1]>

From trace-cmd 3.4-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.