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.
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.
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
Written by Steven Rostedt, <m[blue]firstname.lastname@example.org>