Hi,
I am not sure this is an appropriate way to ask for help!
For your question, you can actually check the warning in the doc of the function you’re using: torch.utils.bottleneck — PyTorch 1.9.1 documentation 2
It does say that because CUDA is async, if you do not do any syncing, the ops that synchronize (like cpu()) will have abnormally high impact.
The advice above was to use the benchmark tool which does have a mode to properly time cuda code.