TRACE-CMD-RESET(1) libtracefs Manual TRACE-CMD-RESET(1)
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
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
1. rostedt@goodmis.org
mailto:rostedt@goodmis.org
libtracefs 04/08/2024 TRACE-CMD-RESET(1)
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