Nearly all of the "heavy lifting" as it were are C or C++ libraries. Python is just the 'plumbing' level. It is not dissimilar to using MATLAB where the drivers

Nearly all of the "heavy lifting" as it were are C or C++ libraries. Python is just the 'plumbing' level. It is not dissimilar to using MATLAB where the drivers are all optimized code but the connection between them is MATLAB. This design pattern is a common of nearly all SDR frameworks (Gnuradio, Redhawk, Pothos, Etc.) The "interconnect" between processing elements is typically shared memory, and that is why it lends itself to GPU work as well. That said, since my head is most comfortable thinking in C, I tend to write stuff in C rather than Python :-).