Le dim. 19 janv. 2020 à 12:51, Alan Mackenzie <address@hidden> a écrit :
Hello, Fabrice.
On Sun, Jan 19, 2020 at 10:34:07 +0100, Fabrice Popineau wrote:
> Hi,
> Out of curiosity, I timed 'emacs -Q' ....
Which version of Emacs?
Current master.
Emacs is compiled with gcc 9.2.0 (MSYS2) and 7.4.0 (Ubuntu)
and CFLAGS = -g3 -O2 -gdwarf-2
> .... scrolling through an elisp buffer: I started the timer by hand and
> scrolled down for 1000 lines ....
How, exactly, did you do the scrolling? How did you stop the scrolling
at 1000 lines? Do you get this slowness on any elisp buffer, or is it a
particular one?
I used my phone timer. It was my init.el file but I get the same result with dired.el
> .... and it took 45s on Windows/WSL and 35s on Windows/native.
That is slow indeed.
Definitely.
Have you tried profiling this scrolling, yet? If not, I suggest you do,
with M-x profiler-start <CR> <CR>, running the scrolling, then M-x
profiler-report. In the report buffer, hit <CR> to get successively
deeper results.
This may well give you an idea where the slowness is happening.
You are right. I should have tried it right away.
I am not sure there is anything unexpected in there.
The lisp machinery interpreting commands accounts for most of the time,
especially `completing-read-default' and I wonder why? Is it because of the `make-composed-keymap' call
which occurs in `completing-read-default'?
Best regards,
Fabrice