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Commit 78a89463 authored by Lecopzer Chen's avatar Lecopzer Chen Committed by Jonathan Corbet
Browse files

Documentation: {u,k}probes: add tracing_on before tracing 



After following the document step by step, the `cat trace` can't be
worked without enabling tracing_on and might mislead newbies about
the functionality.

Signed-off-by: default avatarLecopzer Chen <lecopzer.chen@mediatek.com>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 462e5a52

Documentation/trace/kprobetrace.rst

+6 −0
Original line number Diff line number Diff line
@@ -189,6 +189,12 @@ events, you need to enable it. 
  echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable

  echo 1 > /sys/kernel/debug/tracing/events/kprobes/myretprobe/enable



Use the following command to start tracing in an interval.

::

    # echo 1 > tracing_on

    Open something...

    # echo 0 > tracing_on



And you can see the traced information via /sys/kernel/debug/tracing/trace.

::

Documentation/trace/uprobetracer.rst

+6 −1
Original line number Diff line number Diff line
@@ -152,10 +152,15 @@ events, you need to enable it by:: 


    # echo 1 > events/uprobes/enable



Lets disable the event after sleeping for some time.

Lets start tracing, sleep for some time and stop tracing.

::



    # echo 1 > tracing_on

    # sleep 20

    # echo 0 > tracing_on



Also, you can disable the event by::



    # echo 0 > events/uprobes/enable



And you can see the traced information via /sys/kernel/debug/tracing/trace.