NAME

       trace-cmd-reset - turn off all Ftrace tracing to bring back full performance

SYNOPSIS

       trace-cmd reset [OPTIONS]

DESCRIPTION

       The trace-cmd(1) reset command turns off all tracing of Ftrace. This will bring back the
       performance of the system before tracing was enabled. This is necessary since
       trace-cmd-record(1), trace-cmd-stop(1) and trace-cmd-extract(1) do not disable the tracer,
       event after the data has been pulled from the buffers. The rational is that the user may
       want to manually enable the tracer with the Ftrace pseudo file system, or examine other
       parts of Ftrace to see what trace-cmd did. After the reset command happens, the data in
       the ring buffer, and the options that were used are all lost.

OPTIONS

       Please note that the order that options are specified on the command line is significant.
       See EXAMPLES.

       -b buffer_size
           When the kernel boots, the Ftrace ring buffer is of a minimal size (3 pages per CPU).
           The first time the tracer is used, the ring buffer size expands to what it was set for
           (default 1.4 Megs per CPU).

               If no more tracing is to be done, this option allows you to shrink the
               ring buffer down to free up available memory.

               trace-cmd reset -b 1

               The buffer instance affected is the one (or ones) specified by the most
               recently preceding *-B*, *-t*, or *-a* option:

               When used after *-B*, resizes the buffer instance that precedes it on
               the command line.

               When used after *-a*, resizes all buffer instances except the top one.

               When used after *-t* or before any *-B* or *-a*, resizes the top
               instance.

       -B buffer-name
           If the kernel supports multiple buffers, this will reset the trace for only the given
           buffer. It does not affect any other buffer. This may be used multiple times to
           specify different buffers. The top level buffer will not be reset if this option is
           given (unless the -t option is also supplied).

       -a
           Reset the trace for all existing buffer instances. When this option is used, the top
           level instance will not be reset unless -t is given.

       -d
           This option deletes the instance buffer(s) specified by the most recently preceding -B
           or -a option. Because the top-level instance buffer cannot be deleted, it is invalid
           to use this immediatly following -t or prior to any -B or -a option on the command
           line.

       -t
           Resets 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 reset.

EXAMPLES

       Reset tracing for instance-one and set its per-cpu buffer size to 4096kb. Also deletes
       instance-two. The top level instance and any other instances remain unaffected:

           trace-cmd reset -B instance-one -b 4096 -B instance-two -d

       Delete all instance buffers. Top level instance remains unaffected:

           trace-cmd reset -a -d

       Delete all instance buffers and also reset the top instance:

           trace-cmd reset -t -a -d

       Invalid. This command implies an attempt to delete the top instance:

           trace-cmd reset -a -t -d

       Reset the top instance and set its per-cpu buffer size to 1024kb. If any instance buffers
       exist, they will be unaffected:

           trace-cmd reset -b 1024

SEE ALSO

       trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-start(1),
       trace-cmd-stop(1), trace-cmd-extract(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

                                            03/23/2020                         TRACE-CMD-RESET(1)