title: Tensorflow C++ evaluation performance worse than Python one
body: <p>I built an LSTM classifier in Tensorflow (using Python) and now I am doing a series of benchmarks to measure the execution performance. The benchmark code loads the model that was saved during training and executes it for a number of inputs. I have both a Python benchmark and a C++ one. </p>
  
  <p>I get <code>5ms</code> per input when using Python (on CPU) and <code>68ms</code> when using C++. I was expecting C++ version to have at least similar performance.</p>
  
  <p>What can cause this difference ? I am not familiar with the internals of Tensorflow, but one of my guesses is that Python version uses BLAS (my numpy is linked with blas) and C++ not. If yes, does that mean that some graph operations are executed in Python ?</p>