[bootlin/training-materials updates] master: Real-time lab: explain why we're testing with load first before using chrt (3baf3f94)

[Michael Opdenacker]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/3baf3f945f4aad5c266c0ea136899e55af7e0bc6

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

commit 3baf3f945f4aad5c266c0ea136899e55af7e0bc6
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Fri May 21 10:13:23 2021 +0200

    Real-time lab: explain why we're testing with load first before using chrt
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


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

3baf3f945f4aad5c266c0ea136899e55af7e0bc6
 labs/sysdev-real-time/sysdev-real-time.tex | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/labs/sysdev-real-time/sysdev-real-time.tex b/labs/sysdev-real-time/sysdev-real-time.tex
index d0f4ed1d..165d9887 100644
--- a/labs/sysdev-real-time/sysdev-real-time.tex
+++ b/labs/sysdev-real-time/sysdev-real-time.tex
@@ -170,13 +170,20 @@ Now, do the following tests:
   \code{99}, using the \code{chrt} command.
 \end{itemize}
 
+The above tests should confirm that once your program is no longer
+alone in the system, if you don't run it with the top real-time
+priority, the worst case latencies can really be unbounded.
+
+Therefore, in all the next tests, the program will be run under
+heavy load and through \code{chrt}.
+
 \subsection{Testing the preemptible kernel}
 
 Recompile your kernel with \kconfig{CONFIG_PREEMPT} enabled, which
 enables kernel preemption (except for critical sections protected by
 spinlocks).
 
-Run the \code{rttest} program again, with workload, under this new
+Run the \code{rttest} program again under this new
 preemptible kernel and compare the results.
 
 \subsection{Compiling and testing the PREEMPT\_RT kernel}