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Message-ID: <1557397876-18153-1-git-send-email-lecopzer.chen@mediatek.com>
Date: Thu, 9 May 2019 18:31:16 +0800
From: <lecopzer.chen@...iatek.com>
To: <linux-kernel@...r.kernel.org>, <linux-doc@...r.kernel.org>
CC: <corbet@....net>, <mhiramat@...nel.org>,
<srv_heupstream@...iatek.com>, <yj.chiang@...iatek.com>,
Lecopzer Chen <lecopzer.chen@...iatek.com>
Subject: [PATCH] Documentation: {u,k}probes: add tracing_on before tracing
From: Lecopzer Chen <lecopzer.chen@...iatek.com>
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 <lecopzer.chen@...iatek.com>
---
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.
--
2.18.0
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