bug#25943: 21.5 Frame Display Difficulties

[<david@ngdr.net>]

Hello Martin,

The summary conclusion is that Problem 3 exists both with and without GTK.

The results are somewhat fascinating because of the differences in
performance, which, of course, you cannot see.  Sometimes problem 3 is
easy to see, sometimes it takes several frame creations and deletions.
There is one result where running over the network improves performance!
Running over the network is included because the results, and what I see,
make it hard to avoid speculating that timing/race conditions are at the
root of problem 3.

Here is some detail.  Computer Mneme and Erota run Linux Mint 18.1,
computer Thalia runs Trisquel 7.  I run emacs on all three, sometimes over
my small network.

A "No" entry for problem 3 really means "Not Yet"; but I have tried many
times to generate the problem.

Sometimes it is possible to see the separation of the emacs frame and the
WM window.  There can be a short period before the two coalesce
(flashing), or the two may stay separated.

Version Run     Toolkit     Display     Problem3
25.1    Mneme   GTK3     Mneme    Yes
                          GTK3     Thalia      No       This is a
surprising result,
                                                                    given
the above; it can be
                                                                    viewed
as a performance
                                                                   
improvement.
                                         Erota       Yes      Yes, but
very rare.

25.1      Thalia  No           Thalia      Yes      Yes, but rare.
                                        Mneme    Yes    
26.0.50 Thalia  No           Thalia      Yes
                                        Mneme    Yes      This shows both
short period
                                                                    and
permanent frame separation.

25.1       Erota   No           Erota        Yes
                                         Mneme    Yes
26.0.50 Erota   GTK3        Erota       No
                                         Mneme    No



==========================================================================
==========================================================================

Mneme runs 25.1

It was created by GNU Emacs configure 25.1, which was
generated by GNU Autoconf 2.69.  Invocation command line was

  $ ./configure 

## --------- ##
## Platform. ##
## --------- ##

hostname = Mneme
uname -m = x86_64
uname -r = 4.4.0-53-generic
uname -s = Linux
uname -v = #74-Ubuntu SMP Fri Dec 2 15:59:10 UTC 2016

skip ....

#define EMACS_CONFIG_FEATURES "XPM JPEG TIFF GIF PNG SOUND DBUS GSETTINGS
 NOTIFY FREETYPE XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11"

configure: exit 0

==========================================================================
==========================================================================

Thalia runs 25.1 and 26.0.50

It was created by GNU Emacs configure 25.1, which was
generated by GNU Autoconf 2.69.  Invocation command line was

  $ ./configure --with-x-toolkit=no

## --------- ##
## Platform. ##
## --------- ##

hostname = Thalia
uname -m = x86_64
uname -r = 3.13.0-113-lowlatency
uname -s = Linux
uname -v = #160+7.0trisquel2 SMP PREEMPT Thu Mar 16 13:56:41 UTC 2017

skip ....

#define EMACS_CONFIG_FEATURES "XPM JPEG TIFF GIF PNG SOUND GSETTINGS
 NOTIFY ACL GNUTLS FREETYPE XFT ZLIB X11"

configure: exit 0

==========================================================================

It was created by GNU Emacs configure 26.0.50, which was
generated by GNU Autoconf 2.69.  Invocation command line was

  $ ./configure --without-makeinfo --with-x-toolkit=no

## --------- ##
## Platform. ##
## --------- ##

hostname = Thalia
uname -m = x86_64
uname -r = 3.13.0-113-lowlatency
uname -s = Linux
uname -v = #160+7.0trisquel2 SMP PREEMPT Thu Mar 16 13:56:41 UTC 2017

skip ....

#define EMACS_CONFIG_FEATURES "XPM JPEG TIFF GIF PNG SOUND GSETTINGS
 NOTIFY ACL GNUTLS FREETYPE XFT ZLIB X11"

configure: exit 0

==========================================================================
==========================================================================

Erota runs 25.1 and 26.0.50

It was created by GNU Emacs configure 25.1, which was
generated by GNU Autoconf 2.69.  Invocation command line was

  $ ./configure --with-x-toolkit=no

## --------- ##
## Platform. ##
## --------- ##

hostname = Erota
uname -m = x86_64
uname -r = 4.4.0-53-generic
uname -s = Linux
uname -v = #74-Ubuntu SMP Fri Dec 2 15:59:10 UTC 2016

skip ....

#define EMACS_CONFIG_FEATURES "XPM JPEG TIFF GIF PNG SOUND DBUS GSETTINGS
 NOTIFY GNUTLS FREETYPE XFT ZLIB X11"

configure: exit 0

==========================================================================

It was created by GNU Emacs configure 26.0.50, which was
generated by GNU Autoconf 2.69.  Invocation command line was

  $ ./configure --without-makeinfo

## --------- ##
## Platform. ##
## --------- ##

hostname = Erota
uname -m = x86_64
uname -r = 4.4.0-53-generic
uname -s = Linux
uname -v = #74-Ubuntu SMP Fri Dec 2 15:59:10 UTC 2016

skip ....

#define EMACS_CONFIG_FEATURES "XPM JPEG TIFF GIF PNG SOUND DBUS GSETTINGS
 NOTIFY GNUTLS FREETYPE XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11"

configure: exit 0

==========================================================================
==========================================================================




On Fri, 07 Apr 2017 07:56:28 +0200, martin rudalics <rudalics@gmx.at>
wrote:
>> Unfortunately, problem 3 is alive and well; I shall write again if and
>  > when I have data that looks useful.  I shall address your most recent
>  > questions as well.  If you have any ideas that you would like me to
try,
>  > please let me know.
> 
> Build 26.0.50 with any of the other toolkits (Lucid, Motif) or without
> toolkit support and tell me whether the problem persists.  This way we
> can at least rule out that this is a GTK specific bug (which is always
> the major first step with GNU/Linux builds on graphical terminals)
> 
> martin