Hi,
So indeed, this 3 is the kernel that computed the forward pass.
It is called from this 5 function that performs the forward pass.
This one is used in an automatically generated wrapper called CudaSpatialDepthwiseConvolution_updateOutput which is then exposed to python as CudaSpatialDepthwiseConvolution_updateOutput (same name). Which you can then access from python at torch._C._THNN.CudaSpatialDepthwiseConvolution_updateOutput.