[FE training-materials-updates] ftrace is now based on tracefs, not debugfs
Michael Opdenacker
michael.opdenacker at free-electrons.com
Thu Nov 2 12:40:26 CET 2017
Repository : git://git.free-electrons.com/training-materials.git
On branch : master
Link : http://git.free-electrons.com/training-materials/commit/?id=d2fe675c3512f975e961a9cf7b04157ce03cb23c
>---------------------------------------------------------------
commit d2fe675c3512f975e961a9cf7b04157ce03cb23c
Author: Michael Opdenacker <michael.opdenacker at free-electrons.com>
Date: Thu Nov 2 12:40:26 2017 +0100
ftrace is now based on tracefs, not debugfs
Signed-off-by: Michael Opdenacker <michael.opdenacker at free-electrons.com>
>---------------------------------------------------------------
d2fe675c3512f975e961a9cf7b04157ce03cb23c
slides/sysdev-realtime/sysdev-realtime.tex | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/slides/sysdev-realtime/sysdev-realtime.tex b/slides/sysdev-realtime/sysdev-realtime.tex
index 5a4d057..b453089 100644
--- a/slides/sysdev-realtime/sysdev-realtime.tex
+++ b/slides/sysdev-realtime/sysdev-realtime.tex
@@ -857,14 +857,13 @@ timer_delete(timer_t timerid)
\begin{frame}
\frametitle{Using ftrace}
\begin{itemize}
- \item Tracing information available through the debugfs virtual fs
- (\code{CONFIG_DEBUG_FS} in the {\em Kernel Hacking} section)
+ \item Tracing information available through the \code{tracefs} virtual fs
\item Mount this filesystem as follows:\\
- \code{mount -t debugfs nodev /sys/kernel/debug}
+ \code{mount -t tracefs nodev /sys/kernel/tracing}
\item When tracing is enabled (see the next slides), tracing
- information is available in \code{/sys/kernel/debug/tracing}.
+ information is available in \code{/sys/kernel/tracing}.
\item Check available tracers in
- \code{/sys/kernel/debug/tracing/available_tracers}
+ \code{/sys/kernel/tracing/available_tracers}
\end{itemize}
\end{frame}
@@ -876,13 +875,13 @@ timer_delete(timer_t timerid)
\item Maximum recorded time between waking up a top priority task
and its scheduling on a CPU, expressed in us.
\item Check that \code{wakeup} is listed in
- \code{/sys/kernel/debug/tracing/available_tracers}
+ \code{/sys/kernel/tracing/available_tracers}
\item To select, reset and enable this tracer:
\begin{block}{}
\begin{verbatim}
-echo wakeup > /sys/kernel/debug/tracing/current_tracer
-echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
-echo 1 > /sys/kernel/debug/tracing/tracing_enabled
+echo wakeup > /sys/kernel/tracing/current_tracer
+echo 0 > /sys/kernel/tracing/tracing_max_latency
+echo 1 > /sys/kernel/tracing/tracing_enabled
\end{verbatim}
\end{block}
\item Let your system run, in particular real-time tasks.\\
@@ -890,13 +889,13 @@ echo 1 > /sys/kernel/debug/tracing/tracing_enabled
\item Disable tracing:\\
\begin{block}{}
\begin{verbatim}
-echo 0 > /sys/kernel/debug/tracing/tracing_enabled
+echo 0 > /sys/kernel/tracing/tracing_enabled
\end{verbatim}
\end{block}{}
\item Read the maximum recorded latency and the corresponding trace:\\
\begin{block}{}
\begin{verbatim}
-cat /sys/kernel/debug/tracing/tracing_max_latency
+cat /sys/kernel/tracing/tracing_max_latency
\end{verbatim}
\end{block}{}
\end{itemize}
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