Thanks for replaying!!
However, when I read the document of DataParallel and DistributedDataParallel  3, I think it would not help me to reduce the execution time because I do not need the backward pass.
> assert any((p.requires_grad for p in module.parameters())), (
>             "DistributedDataParallel is not needed when a module "
>             "doesn't have any parameter that requires a gradient."
>         )

I will try with it and tell u the result.