I recently ported a reinforcement learning algorithm from PyTorch to Julia. I did my best to keep the implementations the same, with the same hyperparameters, network sizes, etc. I think I did a pretty good job because the performance was similar, solving the CartPole environment in the a similar number of steps, etc.<p>The Julia implementation ended up being about 2 to 3 times faster. I timed the core learning loops, the network evaluations and gradient calculations and applications, and PyTorch and Julia performed similar here. So it wasn't that Julia was faster at learning. Instead it was all the in-between, all the "book keeping" in Python ended up being much faster in Julia, enough so that overall it was 2 to 3 times faster.<p>(I was training on a CPU though. Things may be different if you're using a GPU, I don't know.)