[bootlin/training-materials updates] master: Boot time labs: advise to keep copies of all grabserial logs (ed874435)

Michael Opdenacker michael.opdenacker at bootlin.com
Fri Apr 2 17:41:18 CEST 2021

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/ed87443511c413d59280ddeecdf82fdf4389cbf6


commit ed87443511c413d59280ddeecdf82fdf4389cbf6
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Fri Apr 2 17:41:18 2021 +0200

    Boot time labs: advise to keep copies of all grabserial logs
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


 labs/boot-time-application/boot-time-application.tex          |  9 +++++----
 .../boot-time-filesystem-optimizations.tex                    |  6 +++---
 labs/boot-time-init-scripts/boot-time-init-scripts.tex        |  3 ++-
 .../boot-time-software-measurement.tex                        | 11 +++++++++++
 4 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/labs/boot-time-application/boot-time-application.tex b/labs/boot-time-application/boot-time-application.tex
index cea10335..02a04718 100644
--- a/labs/boot-time-application/boot-time-application.tex
+++ b/labs/boot-time-application/boot-time-application.tex
@@ -267,10 +267,11 @@ Notes:
       something on the screen to make the user wait.
-Update and reboot your system through \code{grabserial}. Fill the below table
-with updated figures (we don't expect earlier parts of system bootup to
-be impacted... scripts may run faster after being recompiled in
+Update and reboot your system through \code{grabserial}, and copy and
+paste your output to \code{boot-time-labs/logs/application.log}.
+Fill the below table with updated figures (we don't expect earlier
+parts of system bootup to be impacted... scripts may run faster after
+being recompiled in \code{Thumb2}):
 \begin{tabular}{| l | l | r |}
diff --git a/labs/boot-time-filesystem-optimizations/boot-time-filesystem-optimizations.tex b/labs/boot-time-filesystem-optimizations/boot-time-filesystem-optimizations.tex
index 1d5cecd2..1d3308ba 100644
--- a/labs/boot-time-filesystem-optimizations/boot-time-filesystem-optimizations.tex
+++ b/labs/boot-time-filesystem-optimizations/boot-time-filesystem-optimizations.tex
@@ -30,8 +30,8 @@ Write the size of the \code{zImage} file in the first row of the below table:
 Go to \code{~/boot-time-labs/rootfs}. You should have a \code{rootfs}
 subdirectory where your root filesystem archive has been extracted.
-Boot your system with \code{grabserial} and start filling the
-table below:
+Boot your system with \code{grabserial}, store its output in
+\code{logs/filesystem-ext4.log}, and start filling the table below:
 \begin{tabular}{| l | l | l | r |}
@@ -57,7 +57,7 @@ sudo dd if=rootfs.sqfs of=/dev/mmcblk0p2
 Then remove the SD card and boot the board with it as usual, and record
+and store measurements.
 Note that we also made tests with {\em ext2}, but they were very close
 to {\em ext4} ones, at least for very small filesystems like this one.
diff --git a/labs/boot-time-init-scripts/boot-time-init-scripts.tex b/labs/boot-time-init-scripts/boot-time-init-scripts.tex
index 7887d796..49ff0238 100644
--- a/labs/boot-time-init-scripts/boot-time-init-scripts.tex
+++ b/labs/boot-time-init-scripts/boot-time-init-scripts.tex
@@ -380,7 +380,8 @@ You should observe substancial space reduction. Let's keep this option!
 Boot your system again.
 If everything works, it's time to boot the system again through
-\code{grabserial} and update the below table:
+\code{grabserial}, store the output to \code{logs/init-scripts.log}
+and update the below table:
 \begin{tabular}{| l | l | r |}
diff --git a/labs/boot-time-software-measurement/boot-time-software-measurement.tex b/labs/boot-time-software-measurement/boot-time-software-measurement.tex
index 388a058d..2d592b93 100644
--- a/labs/boot-time-software-measurement/boot-time-software-measurement.tex
+++ b/labs/boot-time-software-measurement/boot-time-software-measurement.tex
@@ -111,6 +111,17 @@ received, replacing the \code{-e} argument:
 grabserial -d /dev/ttyUSB0 -m "U-Boot SPL" -t -e 30 -q "First frame decoded"
+We now have a complete measurement of the initial boot time of the
+system. We are going to write down the key figures, but it's always
+useful to keep the full log each of our experiments. This is very often
+useful to compare experiments, double check some measurements that
+are surprising and could have been copied in a wrong way, and
+investigate some differences between two different runs.
+So, create the {\code $HOME/boot-time-labs/logs} directory and copy and
+paste the \code{grabserial} output to the \code{initial.log} file in
+this directory.
 \section{Initial measurements}
 Now, take your calculator and fill the below table with the results from your experiments:

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