Hi Alfe, Is there a reason why you are running single threaded? This would the obvious improvement you could make.
Robert. On Fri, Jul 18, 2008 at 4:54 PM, Alf Inge Iversen <[EMAIL PROTECTED]> wrote: > Bob Balfour wrote: > >> Why is the GPU now being delayed so much after >> Draw?? It's almost like the GPU is stuck starting out there mid-frame? > > Hi, > We are dealing with a problem that looks like a closely related problem. > Though we would prefer a kind of delay after draw: > > Our application is a real-time visualization process, and constant frame rate > at 60 Hz is an absolute necessity. Most of the time the load is not not > bigger than 60 Hz should be well maintained, but we still observe severe > glitches in the visualiation, especially when running a mirror view as a > second channel embedded in the main channel. > > Closer investigation (by visually observing the OSG stats, together with > printouts to the console window to detect lost real-tme position data) shows > that even if no datasets are missing and the computing time is well inside > the available time slot, glitches occur. When observing the stats, we > realized that the execution of the GPU happen to be performed sometimes > within the current frame (see attached image GPU-early.jpg), sometimes in the > next frame (see GPU-late.jpg). We could not identify why the execution of the > GPU is sometimes postponed. As you see from the images that even when the > load is minimal, the GPU may be postponed. We observed significant glitches > in the visualization at the moments the execution shifted from one frame to > the other or vice versa. > > Some latency can be accepted, so to ensure a stable image, it should be > possible to lock the start of the GPU processing to the vertical sync. It > would then process on data delivered from the Draw of last frame. This would > give a stable image, in addition to increase the available time for the > processing (full 16 ms for Update, Cull and Draw, and another full 16 ms for > the GPU). > > Is there a way to control the execution start time of the GPU from the > application? > > > -Alf Inge > > ---------------------------------------- > Mr. Alf Inge Iversen, VP Engineering > AutoSim AS, Strandveien 106, 9006 Tromsø > Visit us at http://www.autosim.no > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
