Boot time: add filesystem lab slide and results

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>

slides/boot-time-filesystems/boot-time-filesystems.tex

@@ -194,3 +194,46 @@ \section{Filesystem optimizations}
       boot time) and data partitions (for good runtime performance).
 \end{itemize}
 \end{frame}
+
+\setuplabframe
+{Filesystem optimizations}
+{
+\begin{itemize}
+\item Comparing the boot time performance of various filesystems
+\item Tests with initramfs booting too
+\end{itemize}
+}
+
+\begin{frame}
+\frametitle{Filesystem optimizations - Results}
+Results on BeagleBone Black, Linux 5.11
+\small
+\begin{tabular}{| l || c | c | c | c | c |}
+\hline
+FS image size & \makecell{Buildroot\\ image size} & \makecell{zImage
+size\\ diff} & Time to init & \makecell{Total\\ boot time} & \makecell{ffmpeg\\ exec
+time}\\
+\hline
+ext2 (rev1) only & 62,914,560 & +19,544 & 8.489s & 9.704s & 0.498s \\
+\hline
+ext4 only & 62,914,560 & +241,472 & 8.645s & 9.862s & 0.484s \\
+\hline
+btrfs & 114,294,784 & +546,376 & 11.789s & 12.918s & 0.487s \\
+\hline
+f2fs & 104,857,600 & +167,640 & 8.670s & 9.803s & 0.488s \\
+\hline
+squashfs with lzo & 724,992 & +19,016 & 8.500s & 9.721s & 0.436s \\
+\hline
+erofs & 1,196,032 & +28,072 & 8.510s & 9.795s & 0.491s \\
+\hline
+cramfs & 737,280 & {\em info lost} & 8.499s & 9.875s & 0.656s \\
+\hline
+initramfs & N/A & +169,552 & 8.399s & 9.660s & 0.455s \\
+\hline
+\end{tabular}
+\vfill
+Note: \code{zImage} kernel compressed with LZMA (best but slowest
+compressor), with a 1.162 MB filesystem (size of the tar archive
+generated by Buildroot).
+\end{frame}
+