I think the self cpu total is time of cost on kernel itself, for example, conv2d will call convolution.The Cpu total time cost on conv2d maybe 18.9ms, and time total cost on convolution is 17.9ms, then the self time total of conv2d and convolution is (18.9-17.9=1ms) and 17.9ms.
If some kernle doesn’t call other kernel, then self cpu total is equal to cpu total.
It’s my understanding.
May you a goog day!