The X86_NATIVE_CPU Kconfig build time parameter has been merged for the Linux 6.16 merge window as an easy way to enforce the “-march=native” compiler behavior on AMD and Intel processors to optimize kernel builds for your system's local CPU architecture/family. For those who want “-march=native” for Linux kernel builds on AMD/Intel x86_64 processors, you can easily include a new CONFIG_X86_NATIVE_CPU parameter to set this compiler behavior in local kernel builds. The CONFIG_X86_NATIVE_CPU parameter is considered when compiling the Linux x86_64 kernel with GCC or LLVM Clang when using Clang 19 or later due to a compiler bug in the Linux kernel in older compiler versions. In addition to setting the compiler parameter “-march=native” for Linux kernel C code, enabling this new Kconfig build parameter also sets “-Ctarget-cpu=native” for Rust kernel code.
Yes, most likely need to compile it yourself. Or the distros would need a v1,v2,v3,v4 version. Also you need to know the feature set of you cpu. Distros will probably compile with the lowest common denominator, since those are compatible largest range of cpu's. Cachyos does compile it's packages for v3 optimization, I don't think that needs avx512. So can definitely see some distros trying something out.
I thought the whole point of this setting is not having to specify the features of the CPU. You can compile native versions now if you set things yourself.
Yes it is that, on gentoo I had set it like that for a while. Before I specified it to be sure. I Thought linus, didn't want to have this.