JIT compile set to false in compile function and set to true globally


I have only one model in my code and before compiling the model I am setting this:


but when I compile the model, I set the jit_compile parameter to false.

What I am seeing is, when I add this:


the time by step is almost 2 times less than without setting it.
But I wondering how could this affect the time speed if the jit_compile is set to false?
My assumption is if jit_compile is set to false then, this


would be useless, but seems I am wrong.

Can someone explain this?