how/where to set --fast mode for jruby when using it within jruby/rack inside tomcat?

Question

how/where to set --fast mode for jruby when using it within jruby/rack inside tomcat?

This --fast mode is explained in this page jruby performance tuning

Answer 1

Pass these flags to JVM:

-Djruby.compile.mode=FORCE -Djruby.compile.fastest=true

however you with Tomcat.