Hi All,

    I find this fascinating, and I'll profile as soon as I can. I have two MacBook Pros, a 2018 2.9GHz Intel Core i9, and a 2021 Apple M1 Max. On large loads the latter is about -20% faster than the former. I know this because Tim found a bug in the become primitive with jitted methods that manifested on the Linux ARMv8 (DUAL_MAPPED_CODE_ZONE regime). SImulating the re3co9mpilation of all methods in the system that Tim's example did took about 5 hours on the x86_64 and only 4 on the M1 Max.  But if I compare the JIT benchmarks on them the speeds swing wildly the other way:

These are the average times to JIT all of COmpiledCode's methods (excluding subclasses)

Apple M1:
min        max        average
2.417    79.257    9.674 usecs to JIT
2            20          5.938 number of literals
1           106         17.464 number of bytecodes

Apple 2.9GHz Core i9:
min        max        average
0.705     32.497   4.256 usecs to JIT
2            20          5.938 number of literals
1            106        17.464 number of bytecodes

So there must be some really inefficient thing that the Apple ARMv8 JIT is doing to make it so slow. Interesting :-)