diff --git a/.github/actions/compilers/entrypoint.sh b/.github/actions/compilers/entrypoint.sh
index 17f749d69e..4f9d1304ee 100755
--- a/.github/actions/compilers/entrypoint.sh
+++ b/.github/actions/compilers/entrypoint.sh
@@ -26,7 +26,7 @@ export CONFIGURE_TTY='never'
 export RUBY_DEBUG='ci rgengc'
 export RUBY_TESTOPTS='-q --color=always --tty=no'
 export RUBY_DEBUG_COUNTER_DISABLE='1'
-export GNUMAKEFLAGS="-j$((1 + $(nproc --all)))"
+export GNUMAKEFLAGS="-j$((1 + $(nproc)))"
 
 case "x${INPUT_ENABLE_SHARED}" in
 x | xno | xfalse )
diff --git a/.github/actions/setup/directories/action.yml b/.github/actions/setup/directories/action.yml
index 728e082189..885eabf571 100644
--- a/.github/actions/setup/directories/action.yml
+++ b/.github/actions/setup/directories/action.yml
@@ -110,7 +110,7 @@ runs:
 
     - if: runner.os == 'Linux'
       shell: bash
-      run: echo "GNUMAKEFLAGS=-sj$((1 + $(nproc --all)))" >> "$GITHUB_ENV"
+      run: echo "GNUMAKEFLAGS=-sj$((1 + $(nproc)))" >> "$GITHUB_ENV"
 
     # macOS' GNU make is so old that they doesn't understand `GNUMAKEFLAGS`.
     - if: runner.os == 'macOS'