I wonder how much effect the CPU's register remapping has on these results. Also, they ran it on an ancient CPU, but I'm not sure how much that matters.
Probably not that much because one of the legacies of x86 is that library calling conventions are based on this same registry scarcity. To make an API call there is a convention that a limited number of registers are treated as callee-preserves and the rest are caller-preserves. So your compiler spills them defensively before calling out.
You can make a programming language that uses whatever convention you want, but every time you make a system call or a call to a C or Rust library, you're using essentially an FFI and your FFI logic will have to handle the register spill and recovery to match the convention. And if you convert your code to a library, then it'll have to be dumbed down as well.
This is pretty meaningless without showing any assembly code. What does the inner loop for siphash look like? How many GPRs does it use? Where are the spills placed? What does perf say about any of this?
I wonder how much effect the CPU's register remapping has on these results. Also, they ran it on an ancient CPU, but I'm not sure how much that matters.
Probably not that much because one of the legacies of x86 is that library calling conventions are based on this same registry scarcity. To make an API call there is a convention that a limited number of registers are treated as callee-preserves and the rest are caller-preserves. So your compiler spills them defensively before calling out.
You can make a programming language that uses whatever convention you want, but every time you make a system call or a call to a C or Rust library, you're using essentially an FFI and your FFI logic will have to handle the register spill and recovery to match the convention. And if you convert your code to a library, then it'll have to be dumbed down as well.
This is pretty meaningless without showing any assembly code. What does the inner loop for siphash look like? How many GPRs does it use? Where are the spills placed? What does perf say about any of this?