trace-cmd-snapshot (1) - Linux Manuals

trace-cmd-snapshot: take, reset, free, or show a Ftrace kernel snapshot

NAME

trace-cmd-snapshot - take, reset, free, or show a Ftrace kernel snapshot

SYNOPSIS

trace-cmd snapshot [OPTIONS]

DESCRIPTION

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.

AUTHOR

Written by Steven Rostedt, <m[blue]rostedt [at] goodmis.orgm[][1]>

RESOURCES

git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/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

1.

rostedt [at] goodmis.org

mailto:rostedt [at] goodmis.org