Hi all,
I am the author of shen-elisp [1], an implemenation of the Shen [2]
programming language in Elisp. I've noticed that when I built and ran the
test suite in Emacs 24 (via Arch) and Emacs 25 (compiled in Arch)
(config.log attached) I ran into performance regression where the test
suite went from 55 seconds to 100 seconds to complete. My .emacs (actually
.spacemacs) was identical across both runs. This regression is reproducible
across OS's.

Installing shen-elisp is pretty easy since it's on Melpa [3], but running
the test suite requires the Shen sources.

I realize this is a tedious setup process just to show a perf. bug but
unfortunately I don't have time right now to whittle it down to a minimal
case, however since Emacs 25 is on the brink of release I thought I'd
mention it. Fortunately it's not that hard to show and I am happy to work
with someone if they want to try.

Thanks!
-deech


[1] https://github.com/deech/shen-elisp
[2] http://shenlanguage.org/
[3] https://melpa.org/#/shen-elisp