UpdateTileMappings/CopyTileMappings performance: requesting repro attempts

I'm running into some pretty nasty performance with UpdateTileMappings and CopyTileMappings, and I'm not yet sure if I'm horribly messing something up or if it's caused by the driver/runtime. I don't have any AMD or Intel hardware compatible with D3D12, so I'm having trouble narrowing down the source. If you have a D3D12 compatible machine and you're willing, please download the attached test application and report your results.

 

 

The tests take about a minute to complete on my machine. Careful; it may massively slow down any graphical applications you're running, and the OS UI might be sluggish. And while I haven't seen it happen, it's probably a good idea to take precautions under the assumption that it'll freeze your computer or something. Note that the source requires VS2017 to build.

 

So far, across all the nvidia cards I've tested, some tests finish near instantly, while others take over a second for a single call to UpdateTileMappings/CopyTileMappings.

 

I appreciate any repro attempts, and I would also appreciate it if anyone would check the source for any obvious silly mistakes.

 

And happy new year!