I think you may misunderstand Vert.x's polyglot features:
While vert.x supports many programming languages, all of these are run on the JVM runtime. This means when you use the ruby vert.x API, you're using JRuby; likewise with Javascript run through Rhino, Python through Jython, and Groovy/Scala run through their own interpreter/compilers.
That said, it would definitely be interesting to see the performance implications of using one of those languages and vert.x on the JVM.
While vert.x supports many programming languages, all of these are run on the JVM runtime. This means when you use the ruby vert.x API, you're using JRuby; likewise with Javascript run through Rhino, Python through Jython, and Groovy/Scala run through their own interpreter/compilers.
That said, it would definitely be interesting to see the performance implications of using one of those languages and vert.x on the JVM.