Ruby 2.6's JIT was known to make a Rails application slower, while it achieved a good progress on some other benchmarks.
Will that be beneficial for your application in Ruby 2.7? How many times will it make Rails faster? How much additional memory will it consume? Come to the talk and figure it out.
RubyKaigi 2019 https://rubykaigi.org/2019/presentations/k0kubun.html#apr18
RubyKaigi 2019