A GNOME 3.0 plan [LWN.net]

A GNOME 3.0 plan

Posted Apr 5, 2009 10:36 UTC (Sun) by oak (subscriber, #2786)
In reply to: A GNOME 3.0 plan by Cyberax
Parent article: A GNOME 3.0 plan

> Well, for example QT Creator launches in less than a second on my
computer (from a hot cache) and is very snappy. Anjuta on the other hand,
works noticibly slower.

Without any info about your test setup, this comment is completely
useless. Was this in KDE or Gnome desktop (which version)? Was "Qt
creator" launched with kdeinit? Was Anjuta startup "hot" or "cold" (gconf
etc not running etc)? What kind of X server acceleration you had[2]?
Which versions of the software? Did you make sure you didn't have extra
bg processes taking CPU? How much free memory you had? What theme was
used[1]?

[1] Many distros setup KDE to force some horrible Qt theme on Gtk. I.e.
make Gtk apps use a theme that sets them to load Qt libraries to do the
drawing operations in addition to them loading the Gtk libraries do the
higher level UI stuff...

> As for microbenchmarks - compare QT tesselator which supports OpenGL and
software-only Cairo.

Cairo uses Xrender which can also be HW accelerated (due to complexity of
Xrender, probably not completely). It depends on your graphics driver.
As to HW acceleration, each operation has a setup cost. If the operations
are too small or few, HW "acceleration" can actually make things also
(significantly) slower too...

Cairo and GL also have different targets. Cairo aims for re-producible
results, GL for fast ones.

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A GNOME 3.0 plan

Posted Apr 5, 2009 12:04 UTC (Sun) by Cyberax (✭ supporter ✭, #52523) [Link]

QT Creator does not depend on any KDE software. It's completely self-contained. It used GTK theme which is the default theme on QT 4.5 when running in GNOME environment.

Of course, Anjuta was launched from a hot cache too, without any heavy background processes, etc.

X Server uses proprietary NVidia drivers, but I don't think it makes any difference. I've just retried it with NV driver (no acceleration at all) and there's no difference.

Cairo can use XRender (and OpenGL for that matter) only for compositing, it can't accelerate tesselation and curve drawing. QT also can use slower software renderer if you want quality.