build.sh: refactor & fix ccache

#102 remove IS_LTS env in *.yml, but not change build.sh accordingly, which makes build.sh always selects to non-ccache branch.

Add option parser like that in setup.sh and modify *.yml, which should fix ccache.

Also remove old SMT detection code. `nproc` itself already respects SMT. Like with 8C,16T processor, `nproc` will return 16.

`nproc --all` basically is same as `nproc` but it will ignore cgroup limitation forced by containers like docker, and also on motherboards supporting hotplug cpus it will return max possible cpu slots instead of the number of installed count. So yeah, sometimes `nproc --all` returns a bigger number than `nproc`, but those "extra" cpus aren't actually available for use. So let's just use `nproc`.

But use 2*nproc might still make sense if compilation is actually IO-bounded. I tested nproc vs 2*nproc on my private repo's action. It seems like no noticable difference though. Maybe we should revisit the thread count decision someday later.

(cherry picked from commit f05d3d5c422738ad90237753b9bd60396ded6238)

.github/workflows/build-lts.yml

@@ -79,7 +79,7 @@ jobs:
     - name: Build kernel
       if: ${{ env.REBUILD_FLAG }}
       run: |
-        cd linux && ../build.sh
+        cd linux && ../build.sh --branch LTS
         mv arch/x86/boot/bzImage ../${{ matrix.image-name }}
         cd .. && sha256sum ${{ matrix.image-name }} > ${{ matrix.image-name }}.sha256
 

.github/workflows/build.yml

@@ -92,7 +92,7 @@ jobs:
     - name: Build kernel
       if: ${{ env.REBUILD_FLAG }}
       run: |
-        cd linux && ../build.sh
+        cd linux && ../build.sh --branch MAIN
         mv arch/x86/boot/bzImage ../${{ matrix.image-name }}
         cd .. && sha256sum ${{ matrix.image-name }} > ${{ matrix.image-name }}.sha256
 

build.sh

@@ -1,15 +1,67 @@
-#
-if [ "$(cat /sys/devices/system/cpu/smt/active)" = "1" ]; then
-	export LOGICAL_CORES=$(($(nproc --all) * 2))
-else
-	export LOGICAL_CORES=$(nproc --all)
+#!/bin/bash
+
+usage() {
+	echo "Usage: build.sh [options]"
+	echo "Options:"
+	echo "  -b|--branch <LTS|MAIN>  - Specify the Xanmod kernel branch to build.  (Default: MAIN)"
+	echo "  -j|--jobs <num>         - Specify the number of jobs to use for parallel compilation.  (Default: $(nproc))"
+	echo "  -h                      - Show this help message."
+}
+
+# Parse options with getopt
+temp=$(getopt -o 'b:j:h' --long 'branch:,jobs:,help' -n 'build.sh' -- "$@")
+if [ $? -ne 0 ]; then
+  # unsupported options provided
+  # NOTE: error log not needed, will be reported by getopt
+  usage
+  exit 1
 fi
+eval set -- "$temp"
+unset temp
+while true; do
+  case "$1" in
+	'-b'|'--branch')
+		BRANCH="$2"
+		shift 2
+		# check if branch is LTS or MAIN
+		if [ "$BRANCH" != "LTS" ] && [ "$BRANCH" != "MAIN" ]; then
+          echo "Invalid branch: $BRANCH"
+          exit 2
+        fi
+		continue
+		;;
+	'-j'|'--jobs')
+		LOGICAL_CORES="$2"
+		shift 2
+		continue
+		;;
+	'-h'|'--help')
+		usage
+		exit 0
+		;;
+	'--')
+		shift
+		break
+		;;
+	*)
+		# should not happen
+		echo "Unhandled option: $1"
+		exit 1
+		;;
+	esac
+done
+# Default values
+BRANCH=${BRANCH:-MAIN}
+
+LOGICAL_CORES=${LOGICAL_CORES:-$(nproc)}
+
+#
 # Compile
 #
-if [ "$IS_LTS" = "NO" ]; then
+if [ "$BRANCH" = "MAIN" ]; then
 	echo -e "Using $LOGICAL_CORES jobs for this non-LTS build..."
 	make CC='ccache clang -Qunused-arguments -fcolor-diagnostics' LLVM=1 LLVM_IAS=1 -j$LOGICAL_CORES
-else
+elif [ "$BRANCH" = "LTS" ]; then
 	echo -e "Using $LOGICAL_CORES jobs for this LTS build..."
 	make LLVM=1 LLVM_IAS=1 -j$LOGICAL_CORES
 fi

setup.sh

@@ -104,10 +104,10 @@ loop_apply_patch $PATCH_DIR
 # Apply LTS/MAIN specific patches
 loop_apply_patch $SPESIFIC_PATCH_DIR
 
-if [ "$BRANCH" = "LTS" ]; then
-  cp ../wsl2_defconfig.LTS ./arch/x86/configs/wsl2_defconfig
-else
+if [ "$BRANCH" = "MAIN" ]; then
   cp ../wsl2_defconfig.MAIN ./arch/x86/configs/wsl2_defconfig
+elif [ "$BRANCH" = "LTS" ]; then
+  cp ../wsl2_defconfig.LTS ./arch/x86/configs/wsl2_defconfig
 fi
 
 make LLVM=1 LLVM_IAS=1 wsl2_defconfig