Sounds like you're running it! Since I didn't notice any improvements I started wondering. It only speeds up Ruby itself. In a "real world" web app perfo

Sounds like you're running it! Since I didn't notice any improvements I started wondering. It only speeds up Ruby itself. In a "real world" web app performance, performance is mostly dominated by Ruby/PHP/Java/whatever sitting around and waiting for database queries to execute. So for a lot of web workloads the perf increase won't be huge. If your average endpoint is e.g. 5ms of Ruby and 500ms of DB queries, your max speedup will be negligible if you switch to YJIT... or even if you rewrite the whole app in hand-optimized assembler. (Also gets to the root of why perf-based criticism of Ruby is usually dumb, IMHO. It's usually not the problem)