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  3. trace-cmd
  4. trace-cmd-snapshot(1)

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TRACE-CMD-SNAPSHOT(1)   TRACE-CMD-SNAPSHOT(1)

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.

SEE ALSO

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

AUTHOR

Written by Steven Rostedt, <rostedt@goodmis.org[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@goodmis.org
mailto:rostedt@goodmis.org
08/07/2019