[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>


 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)
   \frametitle{Using ftrace}
-  \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}
@@ -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:
-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
   \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:\\
-echo 0 > /sys/kernel/debug/tracing/tracing_enabled
+echo 0 > /sys/kernel/tracing/tracing_enabled
   \item Read the maximum recorded latency and the corresponding trace:\\
-cat /sys/kernel/debug/tracing/tracing_max_latency
+cat /sys/kernel/tracing/tracing_max_latency

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