bug#68249: 30.0.50; Rmail summaries much slower

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Cc: 68249@debbugs.gnu.org
> Date: Sat, 06 Jan 2024 23:31:45 -0500
> 
>         1573  54% + command-execute
>         1098  38%   Automatic GC
>          159   5% + timer-event-handler
>           25   0% + ...
>           19   0%   redisplay_internal (C function)
>            8   0% + rmail-summary-rmail-update
> 
> I am not sure what that implies, since nothing in a loop
> to check messages appears in it.

You didn't expand the profile.  All those lines which have a "+"
before the function's name are "folded", and you can "unfold" them by
going to the line and pressing RET.  "C-u RET" will unfold _all_ such
folded lines, and you will see the detailed profile of
command-execute, which I think where the problem happens, and where
you will find the loop that checks messages (or a function that runs
such a loop).

> Should I try this in the previous version for comparison?

That could help, yes.  But before that, I think a fully expanded
("unfolded") profile of the current version is needed.

It is also strange that GC takes such a large proportion of time.  It
is possible that the slowdown is because some subroutine makes much
more garbage than the previous implementation did.