Speed up op lookup and registration (#21806)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21806
Dispatcher::findSchema(op_name) now uses a lookup table instead of iterating through the list of operators to find it.
This speeds up op lookup (as in finding the operator handle from the name, not as in finding a kernel when you already have the operator handle)
and it also speeds up op registration since that needs to look if an op with the same name already eists.
Differential Revision: D15834256
fbshipit-source-id: c3639d7b567e4ed5e3627c3ebfd01b7d08b55ac1
