CPU allocation for some of the computational tensors

[greenkeeped]

I checked GPU performance against MTCNN. However, GPU performance of MTCNN does not show a drastic difference compared to CPU.

The entire network of MTCNN is allocated to GPUs. The capture below shows the device allocation for P-Net, which is part of MTCNN.

However, some tensorflow computational modules seem to be CPU-bound.

I wonder what exactly these tensors do.