[bootlin/training-materials updates] master: preempt (f06e4e32)

[Maxime Chevallier]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/f06e4e32bd316aadebc9da8692aa3e4036300aaa

>---------------------------------------------------------------

commit f06e4e32bd316aadebc9da8692aa3e4036300aaa
Author: Maxime Chevallier <maxime.chevallier at bootlin.com>
Date:   Mon Jan 24 15:35:18 2022 +0100

    preempt
    
    Signed-off-by: Maxime Chevallier <maxime.chevallier at bootlin.com>


>---------------------------------------------------------------

f06e4e32bd316aadebc9da8692aa3e4036300aaa
 .../.preempt-rt-benchmarking.tex.swp                    | Bin 0 -> 12288 bytes
 .../preempt-rt-benchmarking/preempt-rt-benchmarking.tex |  16 +++++++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/labs/preempt-rt-benchmarking/.preempt-rt-benchmarking.tex.swp b/labs/preempt-rt-benchmarking/.preempt-rt-benchmarking.tex.swp
new file mode 100644
index 00000000..d01d8430
Binary files /dev/null and b/labs/preempt-rt-benchmarking/.preempt-rt-benchmarking.tex.swp differ
diff --git a/labs/preempt-rt-benchmarking/preempt-rt-benchmarking.tex b/labs/preempt-rt-benchmarking/preempt-rt-benchmarking.tex
index 687d5b75..b6733ba7 100644
--- a/labs/preempt-rt-benchmarking/preempt-rt-benchmarking.tex
+++ b/labs/preempt-rt-benchmarking/preempt-rt-benchmarking.tex
@@ -22,14 +22,23 @@ In the Buildroot \code{make menuconfig} interface, enable the following packages
 	\item fping
 	\item scheduling utilites from the util-linux package
 	\item python3
+	\item screen
 \end{itemize}
 
-Re-build the image, and boot it on the Beaglebone.
+You'll also need to enable a few features in the kernel. Run \code{make linux-menuconfig} and select
+the following options, located in "Kernel Hacking" :
+
+\begin{itemize}
+	\item Compile-time checks and compiler options -> Compile the kernel with debug info
+	\item Tracers -> Function tracer, Interrupts-off tracer, Preemption off tracer, scheduling latency tracer...
+\end{itemize}
+
+Re-build the image, and boot it on the board : \code {make linux-rebuild && make}
 
 Let's first start by establishing the baseline latency by simply running \code{cyclictest} :
 
 \begin{bashinput}
-cyclictest
+cyclictest -p 
 \end{bashinput}
 
 The goal of this lab is to try to lower the latency as much as possible while
@@ -37,7 +46,7 @@ the system is under various types of loads. This will allow us to get the
 best running conditions for our applications.
 
 Some tweaks will really be useful on SMP systems, so don't hesitate to test on
-you own machine !
+your own machine !
 
 Here's a few leads :
 
@@ -61,6 +70,7 @@ Stress the system using several tools :
 \end{itemize}
 
 Some kernel options can also be useful :
+
 \begin{itemize}
 	\item \code{CONFIG_TRACE_HWLAT}
 \end{itemize}