Zero results on NVIDIA Fermi

[ash3D]

Benchmark show zero result on NVIDIA Fermi (GeForce GRX 460). Maybe it is bug in driver.
I inserted Flush() between dispatch and End for timestamp query and this fixed issue. It does not affected results on other GPUs.

[sebbbi]

Sounds like a driver bug. Adding flush between the dispatch and End would likely put the dispatch and profiling end timestamp recording to different command lists, which could add penalty to timing. But since DX11 is a black box, anything really might happen. Porting this tester to DX12 would simplify some things.