Why is Apple Rosetta 2 fast? (2022)

Tangent: also why orbstack, a Docker replacement on Mac, is fast [1] (I'm not affiliated in any way, just a fan and happy user :-).

--

1: https://docs.orbstack.dev/features

OrbStack doesn't use Rosetta 2. It does support Rosetta 2 for Linux, but it's something you would have to go out of your way to use.

I confess I don't really know the technical details of how they use Rosetta, but according to their docs [1]:

"We use Rosetta to emulate x86 programs on Apple Silicon, which is much faster than the commonly-used QEMU."

What I get is that rosetta is used when you run something on Docker that uses x86 architecture (I'm guessing x86_64), which for me is pretty often.

--

1: https://docs.orbstack.dev/architecture#low-level-vm-optimiza...