[racket] R5.3 and #lang web-server compilation

At Sat, 18 Aug 2012 17:29:05 -0400 (EDT), Galler wrote:
> Under 5.3, there's been a near order-of-magnitude improvement in 
> compilation time for the web-server language.
> [...]
> Could I ask what has changed?

I'm not certain, but it might have been the change in free-variable
calculation from a quadratic-time algorithm to a linear-time one (which
is commit 6fded4bac1 along with ee93e35260 in the git repo).

> On a separate topic, I extensively load tested the ffi/com library 
> Saturday through Wednesday. Found nothing adverse to report.

Great!