debian_live_build: Reduce CPU load

During the 'mksquashfs' stage, all available CPUs are used per default.
Reduce this to 3/4 of the amount, to have more CPU power available for
other processes, e.g. openQA workers.
For osuosl3 this means a reduction from 16 to 12 cores.

Signed-off-by: Holger Levsen <holger@layer-acht.org>

bin/reproducible_debian_live_build.sh

@@ -179,6 +179,8 @@ mkdir -p /srv/workspace/live-build
 export BUILDDIR=$(mktemp --tmpdir=/srv/workspace/live-build -d -t ${DESKTOP}-${SUITE}.XXXXXXXX)
 cd ${BUILDDIR}
 export RESULTSDIR=$(mktemp --tmpdir=/srv/reproducible-results -d -t ${PROJECTNAME}-${DESKTOP}-${SUITE}-XXXXXXXX) # accessible in schroots, used to compare results
+# Reduce the CPU load during the mksquashfs step
+export MKSQUASHFS_OPTIONS="-processors $(echo "$(nproc)*3/4" | bc)"
 
 # Fetch the rebuild script (and nothing else)
 output_echo "Fetching the rebuild script."
@@ -277,6 +279,9 @@ if [ $(cat ${RESULTSDIR}/summary_build1.txt ${RESULTSDIR}/summary_build2.txt | g
 	DIFFOSCOPE="$(schroot --directory /tmp -c chroot:jenkins-reproducible-${DBDSUITE}-diffoscope diffoscope -- --version 2>&1)"
 	TMPDIR=${RESULTSDIR}
 	call_diffoscope ${PROJECTNAME} ${DESKTOP}/live-image-amd64.hybrid.iso
+	if [ $RESULT -ne 0 ]; then
+		exit $RESULT
+	fi
 fi
 
 cleanup success

hosts/osuosl3-amd64/etc/sudoers.d/live-build

 Defaults env_keep += "SOURCE_DATE_EPOCH"
 Defaults env_keep += "LIVE_BUILD"
+Defaults env_keep += "MKSQUASHFS_OPTIONS"
 
 jenkins ALL=(root) NOPASSWD: /usr/bin/lb build, \
 	/usr/bin/lb clean --purge, \