CUDA&HIP stream asynchronicity about vkfft HOT 2 OPEN

Hello,

multiple streams was a test to mimic the Vulkan behavior of shader dispatches to the pipeline, where unless synchronized they launch without waiting for completion of the last shader - unlike the kernel model of CUDA, where kernels wait for previous kernels. The usability of it turned out to be very limited - only if there are multiple dispatches of kernel when the grid dimensions go out device limits (65k for y and z). However, these workloads are typically big and utilize GPU fully by themselves with low CPU overhead, so using multiple streams was not useful at all. I think you are correct that the synchronization is messed up currently for this version, I will need to check in detail your changes when I have more time.

Best regards,
Dmitrii

from vkfft.

Sure, the mechanism is described here:

https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#cross-stream-dependencies-and-events

It is just extended to work with arbitrary number of streams.

David

from vkfft.