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.
Please note that the order that options are specified on the command
line is significant. See EXAMPLES.
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
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
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).
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.
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
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.
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
This page is part of the trace-cmd (a front-end for Ftrace) project.
Information about the project can be found at [unknown -- if you
know, please contact firstname.lastname@example.org] If you have a bug report for
this manual page, send it to Steven Rostedt <email@example.com>.
This page was obtained from the project's upstream Git repository
on 2017-03-13. If you discover any rendering problems in this HTML
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the information in this COLOPHON (which is not part of the original
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