Subject: bug#30731: Slower startup using March (27.0.50) build in windows

From: Noam Postavsky <[email-masked]>
Date: Mon, 12 Mar 2018 13:09:13 -0400

On Mon, Mar 12, 2018 at 12:08 PM, Shuguang Sun <[email-masked]> wrote:
> FYI. If put (package-initialize) before custom-set-variables,
>>>> before custom-set-variables : 3.637 sec <<<
> Loading image-file...done
> Loading time...done
> Loading completion...done
> Loading elec-pair...done
> Loading icomplete...done
> Loading ido...done
> Loading avoid...done
> Loading savehist...done
> Loading paren...done
>>>> custom-set-variables time: 10.080 sec <<<
>
> Don't know whether autoloads being triggered. It is hard to test one by one.

Try

...
(require 'trace)
(trace-function 'do-after-load-evaluation)
(custom-set-variables ...)
(untrace-function 'do-after-load-evaluation)

and see if there is a difference in the *trace-output* buffer when you
call package-initialize first.

Maybe also do (mapc #'require '(image-file time completion elec-pair
ido avoid savehist paren)) to get the known loads (which I see listed
in your output above) out of the way.