Created by: tensor-tang

Need discuss about the python interface how to use mkl packed implements.

As this issue is long, I summarize the key points in Chinese as first:

intel对GRU等layer优化（还是使用MKL库，非MKLDNN库）完并通过测试后，python api封装时，cpu模式（同时开启with_mkl=on），python端是否可以默认调用优化过后的c++ layer？

Background

We plan to add MKL Packed implements for RNN layers,(Recurrent Layer, LSTM, and GRU). related #6512 (closed) and #6506 (closed) .

They are total different with MKLDNN, and they will be compiled only if WITH_MKL=ON,

Then we got a problem about how to use it from python side?

Solutions

There are two options:

• Add one more flag: use_mkl_packed just like use_mkldnn. This would make things flexible but complex. If user want to use both. They should add both use_mkldnn=True and use_mkl_packed=True.

• Change use_mkldnn ==> use_mkl, and make use_mkl cover both. This can make users happy, Just use_mkl=True is enough, do not need care which one to choose. But it's not flexible enough.

Which one we should choose? Any suggestion is appreciated.

@wangkuiyi @luotao1