f77b3da74f
Flag some actors that are good candidates for caching in texture memory
(what Clutter calls "offscreen redirect"), thereby mostly eliminating
their repaint overhead.
This isn't exactly groundbreaking, it's how you're meant to use
OpenGL in the first place. But the difficulty is in the design of
Clutter which has some peculiarities making universal caching
inefficient at the moment:
* Repainting an offscreen actor is measurably slower than repainting
the same actor if it was uncached. But only by less than 100%,
so if an actor can avoid changing every frame then caching is usually
more efficient over that timeframe.
* The cached painting from a container typically includes its children,
so you can't cache containers whose children are usually animating at
full frame rate. That results in a performance loss.
This could be remedied in future by Clutter explicitly separating a
container's background painting from its child painting and always
caching the background (as StWidget tries to in some cases already).
So this commit selects just a few areas where caching has been verified
to be beneficial, and many use cases now see their CPU usage halved:
One small window active...... 10% -> 7% (-30%)
...under a panel menu........ 23% -> 9% (-61%)
One maximized window active.. 12% -> 9% (-25%)
...under a panel menu........ 23% -> 11% (-52%)
...under a shell dialog...... 22% -> 12% (-45%)
...in activities overview.... 32% -> 17% (-47%)
(on an i7-7700)
Also a couple of bugs are fixed by this:
https://bugzilla.gnome.org/show_bug.cgi?id=792634
https://bugzilla.gnome.org/show_bug.cgi?id=792633
GNOME Shell
GNOME Shell provides core user interface functions for the GNOME 3 desktop, like switching to windows and launching applications. GNOME Shell takes advantage of the capabilities of modern graphics hardware and introduces innovative user interface concepts to provide a visually attractive and easy to use experience.
For more information about GNOME Shell, including instructions on how to build GNOME Shell from source and how to get involved with the project, see the [project wiki][wiki]
Bugs should be reported to the GNOME bug tracking system.
License
GNOME Shell is distributed under the terms of the GNU General Public License, version 2 or later. See the COPYING file for details.