Re: slow X11 frame creation and refresh after occlusion

[Robert Pluim]

>>>>> On Thu, 04 Feb 2021 16:14:48 -0500, Greg Klanderman <gak@klanderman.net> 
>>>>> said:

>>>>> On February 4, 2021 Robert Pluim <rpluim@gmail.com> wrote:
>>>>> On Wed, 03 Feb 2021 16:52:15 -0500, Greg Klanderman <gak@klanderman.net> 
>>>>> said:
>>>>> On February 1, 2021 Robert Pluim <rpluim@gmail.com> wrote:
    Greg> (frame-parameter nil 'font-backend)
    Greg> (xfthb x)

    Greg> any suggestions for settings I can try?

    >>>> Configure '--with-cairo'. I'm hoping that will be more efficient in
    >>>> terms of loading fonts.

    Greg> OK I will have a look.  Is there any way to determine if font loading
    Greg> is causing significant delay?  And would that be an issue on
    Greg> subsequent to the first frame on a display?

    >> Emacs does a bunch of font-related stuff every time you create a new
    >> graphical frame. You could try running emacs under 'perf' to see if it
    >> gives any insight.

    Greg> OK I built from git, --with-cairo (interestingly configure does not
    Greg> fail if you specify --with-cairo but don't have the libraries
    Greg> installed) and am able to reproduce the issues I was seeing.

Itʼs an option, which means cairo is...optional :-)

(I canʼt think offhand of an emacs configure option that causes
configure to fail if itʼs not satisfied. Someone will now point one
out).

    Greg> It looks like xterm.c has most of the X event handling, so maybe I
    Greg> will try to put in some debug prints to see what's going on, or try
    Greg> one of the X event tracing programs, or 'perf' next..

Good luck. You might want to experiment with
    emacs -xrm "emacs.synchronous: true"
That would make tracing stuff predictably easier.

Robert