Better build script #3195

docker/builder/build.sh

@@ -4,4 +4,11 @@
 mkdir -p /server/build_docker
 cd /server/build_docker
 cmake -G Ninja /server -DENABLE_TESTS=1
-ninja && env TEST_OPT="--skip long compile $TEST_OPT" ctest -V -j $(nproc || grep -c ^processor /proc/cpuinfo)
+
+# Set the number of build jobs to the half of number of virtual CPU cores (rounded up).
+# By default, ninja use all virtual CPU cores, that leads to very high memory consumption without much improvement in build time.
+# Note that modern x86_64 CPUs use two-way hyper-threading (as of 2018).
+# Without this option my laptop with 16 GiB RAM failed to execute build due to full system freeze.
+NUM_JOBS=$(( ($(nproc || grep -c ^processor /proc/cpuinfo) + 1) / 2 ))
+
+ninja -j $NUM_JOBS && env TEST_OPT="--skip long compile $TEST_OPT" ctest -V -j $NUM_JOBS