[bootlin/training-materials updates] master: Boot time slides: add advise about measuring time (4e47bccb)

[Michael Opdenacker]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/4e47bccbd7f216e8ca4a33865c53bce81c9d1756

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

commit 4e47bccbd7f216e8ca4a33865c53bce81c9d1756
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Wed Apr 13 19:01:50 2022 +0200

    Boot time slides: add advise about measuring time
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


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

4e47bccbd7f216e8ca4a33865c53bce81c9d1756
 slides/boot-time-principles/boot-time-principles.tex | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/slides/boot-time-principles/boot-time-principles.tex b/slides/boot-time-principles/boot-time-principles.tex
index f8b9479c..12bd2a5a 100644
--- a/slides/boot-time-principles/boot-time-principles.tex
+++ b/slides/boot-time-principles/boot-time-principles.tex
@@ -63,11 +63,21 @@ We will follow this order during the practical labs.
 \end{frame}
 
 \begin{frame}
-\frametitle{Worst things first!}
+\frametitle{Worst things first and measurement methodology}
 {\em Premature optimization is the root of all evil.\\
 Donald Knuth}
 \begin{itemize}
 \item Taking the time to measure time carefully is important.
+      \begin{itemize}
+           \item Advice to make at least 3 measures for each
+		 configuration you want to measure.
+           \item Pay attention to variations between measures.
+		 Measures are only valuable when there is a low
+		 jitter between them.
+           \item Keep copies of all your logs. Always useful to
+		 double check or analyze measures which are
+                 inconsistent with the others.
+      \end{itemize}
 \item Find the worst consumers of time and address them first.
 \item You can waste a lot of time if you start optimizing
       minor spots first.