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

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

On Sun, Oct 13, 2024 at 10:43 AM Eli Zaretskii <eliz@gnu.org> wrote:
>
> > From: Stefan Kangas <stefankangas@gmail.com>
> > Date: Sun, 13 Oct 2024 09:50:42 +0000
> > Cc: Andrea Corallo <acorallo@gnu.org>, 41646@debbugs.gnu.org,
> >       Stefan Monnier <monnier@gnu.org>
> >
> > Why should this be MS-Windows specific, BTW?  Is slow startup time with
> > many packages much less of an issue on other operating systems?  Is disk
> > access somehow slower on MS-Windows?
>
> I don't think this is Windows-specific, it's just that on Windows the
> gains might be higher.  Disk access is somewhat slower on Windows,
> yes.

Thanks, and append the result on Ubuntu: from 2.132 to 1.573seconds
(383 packages).


On Sun, Oct 13, 2024 at 9:50 AM Stefan Kangas <stefankangas@gmail.com> wrote:
>
> Here's a suggestion:
>
> Since this is about speeding up load time during startup, how about
> adding a new defvar that enables a cache for `require`, and then set
> that to t during startup and nil after?  That would make the feature
> work as expected without any user customization.  In general, this is
> preferable, as this reduces the overall complexity of Emacs, both for
> users and developers.

The "loadhints-cache" is not only for startup, actually it also works
anytime when requiring a feature but the `exec-path' has hundreds of
entries.

Agree, using the "loadhints-cache" in the `require' function native
code will be better than defeine-advice, I'm implementing it now, and
will post a patch later.