[bootlin/training-materials updates] master: boot-time-labs: kernel optimizations: add spreadsheet (ee30638e)

[Michael Opdenacker]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/ee30638e5ef1902566532e3303353bdb7ecb00f3

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commit ee30638e5ef1902566532e3303353bdb7ecb00f3
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Thu Jun 15 10:23:42 2023 +0200

    boot-time-labs: kernel optimizations: add spreadsheet
    
    To help with lpj measurements
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


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ee30638e5ef1902566532e3303353bdb7ecb00f3
 lab-data/boot-time/results/lpj-time.ods    | Bin 0 -> 12776 bytes
 labs/boot-time-kernel/boot-time-kernel.tex |  12 ++++++++----
 labs/boot-time-kernel/lpj-time.png         | Bin 0 -> 75349 bytes
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/lab-data/boot-time/results/lpj-time.ods b/lab-data/boot-time/results/lpj-time.ods
new file mode 100644
index 00000000..7476f791
Binary files /dev/null and b/lab-data/boot-time/results/lpj-time.ods differ
diff --git a/labs/boot-time-kernel/boot-time-kernel.tex b/labs/boot-time-kernel/boot-time-kernel.tex
index 1cfcc62c..86651200 100644
--- a/labs/boot-time-kernel/boot-time-kernel.tex
+++ b/labs/boot-time-kernel/boot-time-kernel.tex
@@ -107,14 +107,18 @@ on the timing of messages in the console, to detect what's taking most
 time in the kernel initialization. That's almost equivalent, but more
 manual.
 
-\section{Optimizing necessary functionality}
+\section{Optimizing necessary functionality - Delay loop calibration}
 
-Measure the boot time by keeping a few \code{grabserial} logs with
-the current kernel.
+Take three measures of the boot time and store them in the first row of
+the \code{boot-time-labs/results/lpj-time.ods} spreadsheet:
+
+\includegraphics[width=0.7\textwidth]{labs/boot-time-kernel/lpj-time.png}
 
 Implement the {\em Preset loops per jiffy} optimization by
 finding the \code{lpj} value and adding it to the kernel command line.
-Measure the time savings.
+
+Take three measures again and store them in the spreadsheet, to compute
+the saved time.
 
 \section{Removing unnecessary functionality}
 
diff --git a/labs/boot-time-kernel/lpj-time.png b/labs/boot-time-kernel/lpj-time.png
new file mode 100644
index 00000000..f8d86500
Binary files /dev/null and b/labs/boot-time-kernel/lpj-time.png differ