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AOT (ahead of time) really does work on whole binaries. That is also why the first launch of an Intel app seems longer sometimes. Intel binary in, ARM binary ou

by anyfoo 4y ago

AOT (ahead of time) really does work on whole binaries. That is also why the first launch of an Intel app seems longer sometimes. Intel binary in, ARM binary out. You're still right that that's not sufficient, for example anything that generates Intel code will definitely need JIT (just in time) translation. But presumably a lot of code will still hit the happy AOP path. That being said, a JIT does not have to be super slow. The early vwmware products, back before there was virtualization support in Intel products, actually had to do some translation as well: https://www.vmware.com/pdf/asplos235_adams.pdf https://www.vmware.com/pdf/asplos235_adams.pdf

Wowfunhappy 4y ago
> That is also why the first launch of an Intel app seems longer sometimes. Intel binary in, ARM binary out. I mean, we can call it an ARM binary or we can call it an instruction cache. I generally prefer the latter term, because what Rosetta produces are not standalone executables, they're incomplete. I don't know how often the happy path is used, but Rosetta can always be observed doing work at runtime. JITs are great and Rosetta 2 is incredible! I just can't imagine it working over any sort of shared filesystem, that would add an incredible amount of latency.