d122b66abc
If the transform matrix is an identity, then positioning wont change and
we can avoid creating the transform node altogether. This is based on
a similar find in GTK today while reducing temporary allocations.
This cuts the number of transforms created in clutter_actor_paint() by
about half under light testing of GNOME Shell from 6.8% to 2.4% of
allocations.
Before:
ALLOCATED TOTAL FUNCTION
[ 20.4 MiB] [ 21.20%] clutter_actor_paint
[ 11.0 MiB] [ 11.45%] clutter_paint_node_paint
[ 6.6 MiB] [ 6.84%] clutter_transform_node_new
[ 2.5 MiB] [ 2.61%] clutter_actor_node_new
After:
ALLOCATED TOTAL FUNCTION
[ 33.4 MiB] [ 24.12%] clutter_actor_paint
[ 26.2 MiB] [ 18.91%] clutter_paint_node_paint
[ 3.4 MiB] [ 2.43%] clutter_actor_node_new
[ 3.3 MiB] [ 2.41%] clutter_transform_node_new
Allocation amounts will have differed due to different amounts of running
time, but the % of allocations has now dropped below
clutter_actor_node_new() which should be expected.
https://gitlab.gnome.org/GNOME/mutter/issues/1056
Mutter
Mutter is a Wayland display server and X11 window manager and compositor library.
When used as a Wayland display server, it runs on top of KMS and libinput. It implements the compositor side of the Wayland core protocol as well as various protocol extensions. It also has functionality related to running X11 applications using Xwayland.
When used on top of Xorg it acts as a X11 window manager and compositing manager.
It contains functionality related to, among other things, window management, window compositing, focus tracking, workspace management, keybindings and monitor configuration.
Internally it uses a fork of Cogl, a hardware acceleration abstraction library used to simplify usage of OpenGL pipelines, as well as a fork af Clutter, a scene graph and user interface toolkit.
Mutter is used by, for example, GNOME Shell, the GNOME core user interface, and by Gala, elementary OS's window manager. It can also be run standalone, using the command "mutter", but just running plain mutter is only intended for debugging purposes.
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