rubocop sample.rb spends most of a call loading code: 686 ms natively, 164 ms once that loading is done in advance (x4.2, one small file, warm daemon). I wrote speedrunner to do that: it keeps the tool loaded in a daemon and forks it per call, with no per-tool setup and the same output as a native run. The cops’ own work is not sped up, and the first call in a fresh environment gains nothing. Linux and macOS. Code and runs: https://github.com/anthonyGosme/speedrunner