[plt-scheme] 3m defaults to --enable-account

Matthew Flatt <mflatt at cs.utah.edu> writes:
> If you need the old 3m collector for some reason, configure with
> --enable-compact. As the name of this flag suggests, the old 3m
> collector tends to keep a smaller memory footprint than the now-default
> collector, but the difference between the two collectors is much less
> significant than the difference between 3m "precise" collection and
> conservative collection. The old collector does not support memory
> accounting.

I'm curious why you folks switched from conservative to precise GC.
(Not questioning the decision at all, just wondering.)  Do you have a
writeup somewhere about the motivation?  Have you measured the
performance impact?