numba includes the following notes which are useful to profiling and identifying which things can be the cause of low performance on an execution:

Supported Python Features: contains documentation on which features from python can be used directly by Numba.

Supported NumPy features: contains documentation on which functions from numpy can be used directly in numba. Note that the parameters supported are a subset of the parameters from numpy.

Command Line Interface / Debugging: contains information on how to obtain the LLVM code or the optimized code, or the final assembly, which might help in identifying potential performance pitfalls.