HI Nicolas, I don't have time right now to write an essay on this stuff, so just a few hints.
When the stats talk about even traversal time etc, they are talking about that the time in milliseconds for that particular traversal. Frame time includes a wait period for vsync to happen (if you have vsync enabled.) Draw dispatch time is the amount of time it takes the OSG to send all the data and commands into the OpenGL FIFO. Draw GPU is the time it takes for the Graphics Processing Unit to do the actual rendering of the data for that frame. As the GPU is a separate processor to the CPU it can work in a parallel as long as the graphics application doesn't force a sync such as by doing a glReadPixels or similar read back from the GPU. The OpenGL FIFO can actually cache several frames of data to facilitate this parallel processing, but the fact it does can complicate how you should interpret the results. Robert. On 13 January 2015 at 21:01, Nicolas Baillard <nicolas.baill...@gmail.com> wrote: > Hello everyone. > > The application I'm working on (a plane simulation) is producing a low > framerate so I'm trying to figure out where the bottleneck is. For that > purpose I'm collecting the stats from the viewer and the camera. But, even > after looking at the code, I have trouble understanding what each stat is > exactly. > > From the viewer I get the following stats : > - Frame duration > - Event traversal time taken > - Update traversal time taken > - Rendering traversal time taken > > Looking at the numbers I get I assume that > > Code: > > Event traversal time taken + Update traversal time taken + Rendering > traversal time taken = Frame duration > > > > Is this correct ? Or is there any other operation within the frame > duration ? > > From the camera I get : > - Cull traversal time taken > - Draw traversal time taken > - GPU draw time > > Here I'm confused. How are "Draw traversal time taken" and "GPU draw time" > different ? > Should this relation be true ? > > Code: > > Cull traversal time taken + Draw traversal time taken + GPU draw time = > Rendering traversal time taken > > > > That's not the case with my application. If I sum the times I get from the > camera then the total time is way below the rendering traversal time. Is > this normal ? What could cause this gap ? > > For testing purpose I only have one view and one camera. How would these > stats sums up if I had several views into a composite viewer and several > cameras ? > > If I had another camera under my view's main camera (a RTT camera for > example), how should I interpret the stats from both camera ? Does the > times from the main camera include the rendering of the nested RTT camera ? > > Regards. > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=62311#62311 > > > > > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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