The road to Zettalinux

I think there is a conflict between the ideas of making 'long' 128-bit wide, using the same C calling conventions as 128-bit user space, and not requiring 128-bit multiplication and division to be fast.

We'll probably keep having this discussion for a while before even the basic type model is decided, including input from more than just kernel developers as well as actual benchmarking of user space software. My guess is that we'll end up with an LLP128 model (128 bit long long, 64 bit long) in both user space and kernel space, as is proposed in the draft riscv128 specs, which in turn means more invasive kernel changes but keeps the types compatible and does not require expensive 128-bit ALUs.