trace-cmd-extract(1) extract out the data from the Ftrace Linux tracer.


trace-cmd extract [OPTIONS]


The trace-cmd(1) extract is usually used after trace-cmd-start(1) and trace-cmd-stop(1). It can be used after the Ftrace tracer has been started manually through the Ftrace pseudo file system.

The extract command creates a trace.dat file that can be used by trace-cmd-report(1) to read from. It reads the kernel internal ring buffer to produce the trace.dat file.


-p plugin

Although extract does not start any traces, some of the plugins require just reading the output in ASCII format. These are the latency tracers, since the latency tracers have a separate internal buffer. The plugin option is therefore only necessary for the wakeup, wakeup-rt, irqsoff, preemptoff and preemptirqsoff plugins.

With out this option, the extract command will extract from the internal
Ftrace buffers.

-O option

If a latency tracer is being extracted, and the -p option is used, then there are some Ftrace options that can change the format. This will update those options before extracting. To see the list of options see trace-cmd-list. To enable an option, write its name, to disable the option append the characters no to it. For example: noprint-parent will disable the print-parent option that prints the parent function in printing a function event.

-o outputfile

By default, the extract command will create a trace.dat file. This option will change where the file is written to.


Extract from the snapshot buffer (if the kernel supports it).


This is the same as the trace-cmd-record(1) --date option, but it does cause the extract routine to disable all tracing. That is, the end of the extract will perform something similar to trace-cmd-reset(1).


Written by Steven Rostedt, <m[blue][email protected]m[][1]>




Copyright (C) 2010 Red Hat, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).