reset-trace man page

reset-trace ā€” reset the state of tracing.

Synopsis

reset-trace [-F] [-h] [-q] [-v]

Description

You will probably never need this tool. If you kill -9 a bcc tool (plus other signals, like SIGTERM), or if a bcc tool crashes, then kernel tracing can be left in a semi-enabled state. It's not as bad as it sounds: there may just be overhead for writing to ring buffers that are never read. This tool can be used to clean up the tracing state, and reset and disable active tracing.

Make sure no other tracing sessions are active. This tool might stop them from functioning (perhaps ungracefully).

This specifically clears the state in at least the following files in /sys/kernel/debug/tracing: kprobe_events, uprobe_events, trace_pipe. Other tracing facilities (ftrace) are checked, and if not in an expected state, a note is printed. All tracing files can be reset with -F for force, but this will interfere with any other running tracing sessions (eg, ftrace).

Requirements

/sys/kernel/debug mounted as debugfs

Options

-F

Force. Will reset all tracing facilities, including those not used by bcc (ftrace). You shouldn't need to use this.

-h

USAGE message.

-q

Quiet. No output while working.

-v

Verbose: print what it is doing.

Examples

Reset the state of tracing:

# reset-trace

Verbose:

# reset-trace -v

Source

This is from bcc.

https://github.com/iovisor/bcc

Also look in the bcc distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool.

OS

Linux

Stability

Unstable - in development.

Author

Brendan Gregg

Info

2016-10-18 USER COMMANDS