bug#41646: Startup in Windows is very slow when load-path contains many

[Lin Sun <sunlin7.mail@gmail.com>]

On Fri, Nov 1, 2024 at 5:08 PM Eli Zaretskii <eliz@gnu.org> wrote:
>
> > From: Lin Sun <sunlin7.mail@gmail.com>
> > Date: Fri, 1 Nov 2024 16:56:59 +0000
> > Cc: Eli Zaretskii <eliz@gnu.org>, stefankangas@gmail.com, acorallo@gnu.org,
> >       41646@debbugs.gnu.org, monnier@gnu.org
> >
> > On Fri, Nov 1, 2024 at 8:17 AM Eli Zaretskii <eliz@gnu.org> wrote:
> > > ...
> > > How will the '"file1" "file2" ...' part be created?
> >
> > For the Emacs built in paths, we can create the (<path> [files])
> > during bootstrap and write to the "subdirs.el", then it will push the
> > extended (<path>, files...) into `load-path'.
>
> I don't understand: isn't this supposed to speed up primarily users
> who have many 3rd-party packages installed?  For them, what happens
> during bootstrap is not relevant.
>
> If all we want is to record the places where bundled files live,
> that's a much easier problem.
Sorry for the fuzz "bootstrap", the "bootstrap" I wanted to say is
part of building steps, like "make bootstrap", then we can build the
files list into the "subdir.el".

Both the startup time and running time will be affected by too many
"load-path" entries.
Like the "package.el", it will add all 300+ packages' paths on the top
of "load-path" at the beginning of startup, the builtin paths will be
on the bottom of "load-path", after that a simple "(require
'<builtin-feature>)" will trigger emacs to walk through the
"load-path" from top to bottom, that leads thouthands
open-attemptions, that happened during emacs startup, or during
running time.