reproduce (this is a W=1 build):
        # https://github.com/xinli-intel/linux-fred-public/commit/9707e868fba6a5cad792a4f4deb3a8db7e194e5c
        git remote add xinli-intel-fred-public https://github.com/xinli-intel/linux-fred-public.git
        git fetch --no-tags xinli-intel-fred-public fix_sp_calculation
        git checkout 9707e868fba6a5cad792a4f4deb3a8db7e194e5c
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/kernel/cpu/