Compile-and-run settings that speed up bignum-intensive apps

[rug]

Applications that employ combinatorial methods frequently need to make huge numbers of calculations involving JRuby bignums.  Such applications should benefit from the following compile-and-run settings:

jruby -J-server -J-Djruby.compile.fastest=true  foo.rb

jruby -J-server -J-Djruby.compile.fastest=true -J-XX:+UseParallelGC  foo.rb

Has anyone found other settings that help ?