Why Sleep blocking all cuda streams?

Accelerated Computing CUDA CUDA Programming and Performance
3

I have checked my system, the Hardware Scheduling is not supported, and my video card needs to output images, so it cannot be switched to TCC mode.

So:
Is sleep or other code blocking cuda streams a known problem?

And is cudaStreamSynchronize/ cudaEventSynchronize blocking other streams a known problem? link here

And there’s no solution?