Re: Question about üarent-frame changes

["Gerd Möllmann" <gerd.moellmann@gmail.com>]

Gerd Möllmann <gerd.moellmann@gmail.com> writes:

> Eli Zaretskii <eliz@gnu.org> writes:
>
>>> From: Gerd Möllmann <gerd.moellmann@gmail.com>
>>> Cc: martin rudalics <rudalics@gmx.at>,  Emacs Devel <emacs-devel@gnu.org>
>>> Date: Wed, 25 Sep 2024 13:13:09 +0200
>>>
>>> > shows 24s with GUI, and 8s on tty. I'm using Alacritty, in case that matters
>>> > (for the KKP keyboard support, not for performance).
>>>
>>> Small correction - I had timed tty build with debug. It's actually 2s
>>> instead of 8s.
>>
>> Thanks.  It would be interesting to know which part takes
>> significantly more time on GUI terminals wrt TTYs.  A tenfold
>> performance difference should be easy to explain, I hope.
>
> I don't seem to get profiling to work on macOS 15 + Xcode 16 at the moment.
>
> Maybe someone else could run the benchmark I posted under perf? It
> should just work with an existing master, or 30, or 29 on GUIs.

Got at least something out of Instruments today. An example run in a
debug build with MPS shows as "Heaviest Stack Trace" this:

21.15 s  94,1 %	0 s	  Main Thread  0x158f26
18.63 s  82,9 %	0 s	                                          apply_lambda
12.11 s  53,9 %	0 s	                                           exec_byte_code
8.04 s  35,8 %	1.00 ms	                                                             CA::Context::commit_transaction(CA::Transaction*, double, double*)
5.33 s  23,7 %	0 s	                                                              CA::Layer::layout_if_needed(CA::Transaction*)
5.32 s  23,7 %	2.00 ms	                                                                redisplay_internal
3.96 s  17,6 %	0 s	                                                                 redisplay_windows
3.56 s  15,8 %	0 s	                                                                     update_frame_tool_bar_1
2.62 s  11,6 %	0 s	                                                                      -[NSToolbar _setConfigurationFromDictionary:notifyFamilyAndUpdateDefaults:upgradedConfiguration:]
1.81 s   8,1 %	0 s	                                                                                    -[NSToolbarView _layoutDirtyItemViewersAndTileToolbar]
854.00 ms   3,8 %	0 s	                                                                                     -[NSToolbarView _configureItemViewersForLayoutIfNecessary]
669.00 ms   3,0 %	0 s	                                                                                       -[NSToolbarItemViewer _configureViewerSize]
397.00 ms   1,8 %	0 s	                                                                                        -[NSToolbarItem _scalableMinSize]
359.00 ms   1,6 %	0 s	                                                                                          -[NSToolbarItem _itemViewMinSize:maxSize:stretchesContent:]
179.00 ms   0,8 %	0 s	                                                                                           _nsis_frameInEngine

I think this this means that the window system itself takes a lot of the
time (CA::..., NS...), plus redisplay on GUI of course, which I would
expect to be a bit slower than on ttys, but mainly the window system.

That's also consistent with the fact that the times differ only a bit
between optimized and debug builds with checking=all.

Not much one can do about that, I guess. At least on macOS, it could
be different on other platforms of course.