'\" t
.\"     Title: trace-cmd-reset
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 02/10/2024
.\"    Manual: libtracefs Manual
.\"    Source: libtracefs
.\"  Language: English
.\"
.TH "TRACE\-CMD\-RESET" "1" "02/10/2024" "libtracefs" "libtracefs Manual"
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.SH "NAME"
trace-cmd-reset \- turn off all Ftrace tracing to bring back full performance
.SH "SYNOPSIS"
.sp
\fBtrace\-cmd reset\fR [\fIOPTIONS\fR]
.SH "DESCRIPTION"
.sp
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 \fItrace\-cmd\-record(1)\fR, \fItrace\-cmd\-stop(1)\fR and \fItrace\-cmd\-extract(1)\fR 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\&.
.SH "OPTIONS"
.sp
Please note that the order that options are specified on the command line is significant\&. See EXAMPLES\&.
.PP
\fB\-b\fR \fIbuffer_size\fR
.RS 4
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)\&.
.sp
.if n \{\
.RS 4
.\}
.nf
If no more tracing is to be done, this option allows you to shrink the
ring buffer down to free up available memory\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
trace\-cmd reset \-b 1
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
The buffer instance affected is the one (or ones) specified by the most
recently preceding *\-B*, *\-t*, or *\-a* option:
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
When used after *\-B*, resizes the buffer instance that precedes it on
the command line\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
When used after *\-a*, resizes all buffer instances except the top one\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
When used after *\-t* or before any *\-B* or *\-a*, resizes the top
instance\&.
.fi
.if n \{\
.RE
.\}
.RE
.PP
\fB\-B\fR \fIbuffer\-name\fR
.RS 4
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
\fB\-t\fR
option is also supplied)\&.
.RE
.PP
\fB\-a\fR
.RS 4
Reset the trace for all existing buffer instances\&. When this option is used, the top level instance will not be reset unless
\fB\-t\fR
is given\&.
.RE
.PP
\fB\-d\fR
.RS 4
This option deletes the instance buffer(s) specified by the most recently preceding
\fB\-B\fR
or
\fB\-a\fR
option\&. Because the top\-level instance buffer cannot be deleted, it is invalid to use this immediatly following
\fB\-t\fR
or prior to any
\fB\-B\fR
or
\fB\-a\fR
option on the command line\&.
.RE
.PP
\fB\-t\fR
.RS 4
Resets the top level instance buffer\&. Without the
\fB\-B\fR
or
\fB\-a\fR
option this is the same as the default\&. But if
\fB\-B\fR
or
\fB\-a\fR
is used, this is required if the top level instance buffer should also be reset\&.
.RE
.SH "EXAMPLES"
.sp
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:
.sp
.if n \{\
.RS 4
.\}
.nf
trace\-cmd reset \-B instance\-one \-b 4096 \-B instance\-two \-d
.fi
.if n \{\
.RE
.\}
.sp
Delete all instance buffers\&. Top level instance remains unaffected:
.sp
.if n \{\
.RS 4
.\}
.nf
trace\-cmd reset \-a \-d
.fi
.if n \{\
.RE
.\}
.sp
Delete all instance buffers and also reset the top instance:
.sp
.if n \{\
.RS 4
.\}
.nf
trace\-cmd reset \-t \-a \-d
.fi
.if n \{\
.RE
.\}
.sp
Invalid\&. This command implies an attempt to delete the top instance:
.sp
.if n \{\
.RS 4
.\}
.nf
trace\-cmd reset \-a \-t \-d
.fi
.if n \{\
.RE
.\}
.sp
Reset the top instance and set its per\-cpu buffer size to 1024kb\&. If any instance buffers exist, they will be unaffected:
.sp
.if n \{\
.RS 4
.\}
.nf
trace\-cmd reset \-b 1024
.fi
.if n \{\
.RE
.\}
.SH "SEE ALSO"
.sp
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)
.SH "AUTHOR"
.sp
Written by Steven Rostedt, <\m[blue]\fBrostedt@goodmis\&.org\fR\m[]\&\s-2\u[1]\d\s+2>
.SH "RESOURCES"
.sp
\m[blue]\fBhttps://git\&.kernel\&.org/pub/scm/utils/trace\-cmd/trace\-cmd\&.git/\fR\m[]
.SH "COPYING"
.sp
Copyright (C) 2010 Red Hat, Inc\&. Free use of this software is granted under the terms of the GNU Public License (GPL)\&.
.SH "NOTES"
.IP " 1." 4
rostedt@goodmis.org
.RS 4
\%mailto:rostedt@goodmis.org
.RE