[QUOTE=mwestphal;1291910]I am working on a complex Qt/OpenGL Application.
Xorg starts leaking in VRAM when i’m using the application and never release the memory, until I restart X of course.
…
The compositor used does not matter, but the leak disappear without a compositor.[/QUOTE]
That’s not too surprising. I was just about to suggest that you disable the compositor. Without that, X itself shouldn’t consume much VRAM.
Do you know what could cause this behavior ?
Compositors use the GPU for composite rendering, so you should expect more GPU memory consumption.
Does consumption grow every time you run your up or is there an upper bound?
What’s the max Xorg consumption you’ve seen when running with the compositor (and without)?
Have you ever run out of VRAM because of this?
It could be a leak, but it could also just be unused GPU memory pooled by the compositor or X via the NVidia driver (e.g. scratch texture memory).
For complete control of your GPU (performance, memory consumption, VSync, latency, etc.), just disable the compositor, and be glad that you have that option. On Windows, DWM (its compositor) has been the cause of needless GPU usage limitations since Vista and now can’t be disabled.
If you can’t or don’t want to just disable the compositor (and IFF this VRAM consumption has become a problem), I’d figure out how to determine 1) exactly what memory is being allocated on the GPU for what purpose and by whom, and 2) what configuration controls in the compositor and X allow you to reduce or at least bound that memory usage.