daz wrote:
> So ...
> 
> Critical Error at line 42 - Attempt to redefine xxxxx while
>  JRpragma "no-slow-core" (or JRopt "O3") is in effect.
> 
> and/or ...
> 
> Helpful message #28: This program could run 3.5 times faster
>  by using the JRpragma "fast-core" (or JRopt "O3") option.

Yes, some of these kinds of things are already in JRuby, such as a 
"fastops" flag to turn on fast math operations or a "threadless" mode 
that doesn't do checks for critical/raise/kill. I'm building in all 
these options as we go so people have the option of turning certain 
performance-killing features off. And so far, people are often glad to 
have them.

- Charlie