trace-cmd-snapshot(1) take, reset, free, or show a Ftrace kernel snapshot


trace-cmd snapshot [OPTIONS]


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 ]



Take a snapshot of the currently running buffer.


Clear out the buffer.


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.


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




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