bug#67672: EMACS - Slow opening files

[Moore, Rider]

Eli,

For the purpose of our business we only want to use Emacs as a text editor.  We 
are working with very large mercurial and git repositories under version 
control.  If files are under version control, is Emacs doing anything extra 
besides opening them as a normal text editor would?

Thanks,

-Rider

-----Original Message-----
From: Eli Zaretskii <eliz@gnu.org>
Sent: Tuesday, December 12, 2023 9:07 AM
To: Moore, Rider <rmoore@cooley.com>
Cc: Chand, Suresh <schand@cooley.com>; 67672@debbugs.gnu.org
Subject: Re: bug#67672: EMACS - Slow opening files

[External]

______________________________________________________________________
> From: "Moore, Rider" <rmoore@cooley.com>
> CC: "Chand, Suresh" <schand@cooley.com>,
>         "67672@debbugs.gnu.org"
>       <67672@debbugs.gnu.org>
> Date: Tue, 12 Dec 2023 15:52:53 +0000
>
> The delay is only present for files located within the Truecrypt volume we 
> are using (essential for our purposes).

OK, this is good to know, thanks.

> Do you know of any commands or settings adjustments needed when working with 
> a Emacs and a Truecrypt volume?

No, I don't.  I don't think we have ever heard about problems with these 
particular volumes.  Which is why I suggested to run this slow operation under 
perf, which will allow you to produce a profile of the code, and hopefully will 
show us which part of the code is the bottleneck.  I don't think we can make 
any progress here unless we understand which parts of the code are slow when 
opening files on Truecrypt volumes.

Another, less convenient method is to step in a debugger through the code in 
find-file and its subroutines, and see which part(s) there take such a long 
time.  Presumably, if this takes minutes, you should be able to identify the 
calls that take such a long time.

As a "leap of faith", how about timing the following, after starting "emacs -Q":

  M-: (insert-file-contents "SOME-FILE") RET

where SOME-FILE is a file on a Truecrypt volume.  Does the above take an 
abnormally long time, or is it as fast as when you do the same with a file on 
any other volume?

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