bug#58634: Long delay with blank screen whilst loading desktop at emacs startup

[Andrea Corallo <akrl@sdf.org>]

Eli Zaretskii <eliz@gnu.org> writes:

>> Date: Wed, 19 Oct 2022 13:28:42 +0000
>> From: Alan Mackenzie <acm@muc.de>
>> 
>> In my current desktop file, I have 166 buffers.  I'm using an up to date
>> Emacs 29.
>> 
>> On loading this desktop into emacs -nw on X Windows, or into a linux
>> console, it takes a long time to load, around 28 seconds.  Of that time,
>> my terminal window/screen is entirely blank for around 18 seconds, with
>> not even a mode line being displayed.
>
> And nothing in the echo-area, either?
>
>> Doing the same in a GUI run on X also takes around 28 seconds to load,
>> but during that time, random buffers are displayed on the screen,
>> complete with mode line.
>> 
>> I think the native compiler is running in the background during this 28
>> seconds, and thus contributes to the relatively long start up time.
>
> To test this hypothesis, leave Emacs alone running until
> list-processes shows an empty list, then restart Emacs.  This time,
> you should not see the delay due to native compilation, so if there
> still is a delay, it is unlikely to be due to native compilation.
>
> In any case, you should be able to see whether it's native compilation
> by watching the emacs --batch processes that run on your system during
> that time.

Yes totally agree, listing processes is the quickest way to confirm this
hypothesis.

Alan please let us know.

  Andrea