Document memory behaviour of command buffers, buffers etc.

[gfx-rs]

Document memory behaviour of command buffers, buffers etc.

[kasper0406]

Thanks for the explanation and pointers for debugging @kvark.
I changed to code to be more aggressive in creating NSAutoreleasePool's and the seems to do the trick well enough.

[kvark]

So your problem is that buffers are not freed properly? Here are some thoughts:

• this crate is responsible to give you the object or reference that you can properly clone or drop without touching the refcounts directly. As far as I know, buffer logic here is correct: creating a buffer gives you a retained object Buffer, dropping it releases the counter.
• Metal runtime can have additional references to your buffers, i.e. when used in a command buffer copy operation. I would expect the references to be released sometime at the callback of command buffer that finishes execution on the GPU
• you can have nested NSAutoreleasePool to release more rapidly
• finally, macOS Instruments have great tooling to show you which objects leak, which are zombies, where the retains/releases are, etc.