Re: emacs rendering comparisson between emacs23 and emacs26.3

[Alan Mackenzie]

Hello, Martin.

On Sat, Apr 04, 2020 at 13:10:43 +0200, martin rudalics wrote:
>  > (time-it (scroll-up) (sit-for 0))

> To avoid confusion - what is 'time-it'?

    (defmacro time-it (&rest forms)
      "Time the running of a sequence of forms using `float-time'.
    Call like this: \"M-: (time-it (foo ...) (bar ...) ...)\"."
      `(let ((start (float-time)))
        ,@forms
        (- (float-time) start)))

> And please note that I did not say that I ran 'scroll-up'.  I did a
> mouse wheel scroll as the OP of that bug requested ....

Sorry.  I thought you were using poetic language when you wrote "one turn
of the wheel".  I didn't have the context of the bug in my head.

Just for comparison, would you please time (scroll-up) (sit-for 0) in
xdisp.c on your machine, to give us a better sense of the relative
speeds.

For what it's worth, I've just tried a fast mouse-wheel scroll in xdisp.c
in X Windows on my machine.  There was no noticeable lag.

> .... and unfortunately I don't know what mouse wheel scrolling does
> here because C-h k on it just gives me

> Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil)
>    help--read-key-sequence()
>    byte-code("\300 C\207" [help--read-key-sequence] 1)
>    call-interactively(describe-key nil nil)
>    command-execute(describe-key)

This doesn't happen to me.  I get the information about mwheel-scroll.

> martin

-- 
Alan Mackenzie (Nuremberg, Germany).