>> MJIT will slow Rails down instead of speeding it up. >> That’s a pretty significant footnote. > Oops. FWIW / from what I remember, generating high-perform

>> MJIT will slow Rails down instead of speeding it up. >> That’s a pretty significant footnote. > Oops. FWIW / from what I remember, generating high-performance native code for Rails was hard (or at least significantly different from optimizing standard benchmark type code). The OMR JIT for Ruby had similar challenges, with at least a few 'at least we didn't make it worse' moments. I was only tangentially involved, but I vaguely recall Rails needing (or at least appearing to need) a lot more inlining and string manipulation optimizations to fly.