bug#67672: EMACS - Slow opening files

[Dmitry Gutov <dmitry@gutov.dev>]

On 13/12/2023 13:49, Eli Zaretskii wrote:
>> From: Ihor Radchenko <yantar92@posteo.net>
>> Cc: Eli Zaretskii <eliz@gnu.org>, "67672@debbugs.gnu.org"
>>   <67672@debbugs.gnu.org>, "Chand, Suresh" <schand@cooley.com>
>> Date: Tue, 12 Dec 2023 21:56:51 +0000
>>
>> "Moore, Rider" <rmoore@cooley.com> writes:
>>
>>> Ah, thank you sooo much!!  I think this fixed our issue.
>>> Thank you for the instructions as well.  Does it matter where we save the test.el file?  Once we run M-x load-file we are done with it?
>>
>> Do note that removing vc-refresh-state may break some things related to
>> version control functionality of Emacs, so what I asked you to do is a
>> workaround at best; not a proper fix.
>>
>> Eli or people more familiar with vc-hg.el internals might ask more
>> questions to narrow down the more precise cause.
>>
>> For now, we just determined that `vc-refresh-state' is slow in your setup.
> 
> Dmitry, any ideas?

Something to try is (setq vc-hg-parse-hg-data-structures nil) and see 
whether that changes something.

Another - is to (setq vc-command-messages t), see what commands are run 
(in *Messages*) and test them in the terminal, comparing performance and 
debugging it on their side (perhaps working with TrueCrypt support, 
reporting that such and such commands are slow).

Finally, if the users only want to run Emacs as a "normal text editor", 
then setting vc-handled-backends to nil would improve performance, while 
removing all the VC related features.