OpenGL cpu benchmark QtQuick vs OSX Native

[bdg85]

Dear all,

I noticed some heavy cpu usage in a QtQuick (using Qt5.5) osx app compared to an equivalent Native OSX app. Around 5% more cpu usage with a simple app, up to 15% more with more complex OpenGL tasks.

Both are using Core profile
Version: 4.1 INTEL-10.6.33
GLSL: 4.10

In QtQuick I do openGL inside a QQuickFramebufferObject as I've seen advised many times.
In OSX I draw inside a subclass of NSOpenGLView.

Here are the OpenGL Profiler statistics: http://pastebin.com/uWyy8RMk
Where you can see that CGLFlushDrawable takes so much longer in QtQuick (avg 15418.39 microsec) than in Native OSX App (avg 1287.65 microsec).

I know that what CGLFlushDrawable really does is to set the internal OpenGL state and then do the drawing, so I wonder if I am misusing QtQuick OpenGL somehow. Here is how I set up OpenGL in QtQuick app:

QSurfaceFormat f;
f.setVersion(4, 1);
f.setProfile(QSurfaceFormat::CoreProfile);
QSurfaceFormat::setDefaultFormat(f);

Then, when setting the framebuffer (inside QQuickFramebufferObject::Renderer method createFramebufferObject):

QOpenGLFramebufferObjectFormat format;
format.setAttachment(QOpenGLFramebufferObject::Depth);
format.setInternalTextureFormat(GL_RGB);
format.setSamples(0);

I really hope there is a solution that makes me achieve similar performance because I really enjoy QML and I'd like to continue using it.

Hardware used:
MacBookPro 13'' with retina screen,
cpu: 3 GHz Intel Core i7
gpu: Intel Iris 1536 MB

[SGaist]

Hi,

I'd recommend bringing this to the interest mailing list. You'll find there Qt's developers/maintainers (This forum is more user oriented) Don't forget to subscribe first.

[bdg85]

@SGaist
Thank you for the reply, SGaist! I'll do it.