Why is JRuby Slow? - Earthly Blog
11 minute read Updated: May 26, 2021 Adam Gordon Bell
Recently, I made some contributions to the continuous integration process for Jekyll. Jekyll is a static site generator created by GitHub and written in Ruby, and it uses Earthly and GitHub Actions to test that it works with Ruby 2.5, 2.7, 3.0, and JRuby.
The Jekyll CI does lots of things in it that a simple Jekyll site build might not but clearly JRuby was slowing the whole process down by a significant amount, and this surprised me: Wasn’t the entire point of using JRuby, and its new brother TruffleRuby, speed? Why was JRuby so slow?
I was very happy to discover the JRuby project, my favorite programming language running on what’s probably the best virtual machine in the world. - Peter Lind
