bug#18522: 24.4.50; mapcar is very slow

[Eli Zaretskii]

> From: Peter Münster <pmlists@free.fr>
> Cc: Lars Ingebrigtsen <larsi@gnus.org>,  18522@debbugs.gnu.org
> Date: Sat, 20 Feb 2016 09:33:20 +0100
> 
> > Nevertheless, profiling parse-time-string on a more fine-grained level
> > seems the way to go.
> 
> How please?

I'd start with profiler.el, to profile the Lisp portions of the
function.  It's probably best to load the .el file first and profile
that, although this could skew the profile (because the byte-compiled
version behaves differently).

Another possibility is to add calls to float-time to time portions of
parse-time-string.