bug#71454: 30.0.50; Performance issues with font selection

[Eli Zaretskii]

> Date: Mon, 10 Jun 2024 09:31:53 -0700
> Cc: jb@jeremybryant.net, 71454@debbugs.gnu.org
> From: Jim Porter <jporterbugs@gmail.com>
> 
> On 6/10/2024 4:53 AM, Eli Zaretskii wrote:
> > My crystal ball says that the expensive part here is character
> > composition.  The above characters belong to scripts that require
> > extensive composition rules, take a look at indian.el and its complex
> > regexps.
> 
> That would show up in a profile, right?

No, because Lisp functions called from C don't show in the profile.

> Here's what I get when I start "emacs -Q", start profiling, and then
> call "C-h v comint-password-prompt-regexp RET". It's not the most
> interesting profile since most of it is probably in C code. I do see
> 'auto-compose-chars' in there, however it's got ~0% of the samples
> from the profiler.

As expected, see above.