One of the challenges with JIT compilers is that they always incur some amount of memory overhead over interpreters. At the most basic level, a JIT compiler needs to generate executable machine code, which an interpreter doesn’t, so JIT compilers must use more memory than interpreters. On top of that, however, JIT compilers also need to allocate memory for auxiliary data structure (metadata), which can also add quite a bit of extra memory overhead.
Ruby 3.2’s YJIT is Production-Ready by Shopify
Josh Beckman