Hi there,
I have developed an application that should be used as a part of a research project. The application shows some spheres rolling along within a room. For this research project it is really important that all objects are moving very smooth.
My problem is that the objects within the scene are all stuttering every some seconds and I have no clue why. As we were not able to find any issues about the code I wrote a simple application just rotating a single triangle on the screen. I have tried this on a GLUT and a SDL rendering canvas and I could see the same behavior in this application. The triangle seems to get a little slower or faster for some fraction of a second and continues normally. I tried the application on several systems including Windows and Linux on different graphic cards (all nVidia devices) and I could see the same behavior on every system. I even tried it on a NVIDIA’s Quadro FX 5800 graphics card where it run (vsync disabled) at about 10.000 fps. I have tried to enabe or disable the vsync but it did not change anything.
We excluded CPU switches as the problems source by fixing the process to a single core. The system we used for testing does not have any SpeedStepping or other stuff enabled. As we did not trust in the real time clock on the system we have even read the CPU steps between two frames directly from the CPU which hasn’t had any effect on the problem.
As I told before the vsync on the system was enabled. To exclude this as a problem we also disabled the vsync which did not change anything. We sampled the number of CPU cycles between two frames but we were not able to recognize any major variations. All variations were smaller than 4 ms on all systems.
So I have no idea where to search for a solution anymore. Anyone here having any idea why I get those stuttering movements?