[racket] Performance difference between BSL and #lang racket

> What language difference(s) might be responsible for the vast performance difference we're observing?  If it would be helpful to see the code I can share it, but it's about 1000 LoC and I don't think it's proper to post it publicly.  I've tried to construct a small program that shows the same difference, but haven't managed; I don't, however, see anything in his code that would be obviously responsible.

That's unusual!  Do you have enough experience to use the statistical
profiler?  If so, then sharing the profiling data will help.

I think someone needs to run the code and profile.  Nothing obvious
comes to mind with regards to BSL and performance.