WholeStageCodegenTransformer's duration metrics

[xumingming]

We know that WholeStageCodegenTransformer in Gluten contains a list of vectorized native operators, as these native operators are not fused together, so each of them has accurate timing metrics, do we expect the sum of durations of all native operators to be close to the duration of WholeStageCodegenTransformer itself? If not what causes the gap?

Here is an snapshot:

WholeStageCodegenTransformer's duration metric(88.14h) is much larger than native operators' duration sum(30.95h = 9.5h + 14.43h + 7.02h)