From 78a89463a31ce463a4b968553f57ff9932a0697f Mon Sep 17 00:00:00 2001 From: Lecopzer Chen Date: Thu, 9 May 2019 18:31:16 +0800 Subject: [PATCH] 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: Lecopzer Chen Acked-by: Masami Hiramatsu Signed-off-by: Jonathan Corbet --- Documentation/trace/kprobetrace.rst | 6 ++++++ Documentation/trace/uprobetracer.rst | 7 ++++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst index 235ce2ab131a..baa3c42ba2f4 100644 --- a/Documentation/trace/kprobetrace.rst +++ b/Documentation/trace/kprobetrace.rst @@ -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. :: diff --git a/Documentation/trace/uprobetracer.rst b/Documentation/trace/uprobetracer.rst index 4346e23e3ae7..0b21305fabdc 100644 --- a/Documentation/trace/uprobetracer.rst +++ b/Documentation/trace/uprobetracer.rst @@ -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.