Which Python and which Go? There are so many different implementations and different versions of those implementations that this broad statement is meaningless.
From what I have installed on my machine, CPython 3.11.6 seems to take around 80ns to call a C function, gc 1.22.0 takes around 50ns to call the same C function, and tinygo 0.32.0 only takes around 1ns!
Such benchmarking is always fraught with problems, so your milage may vary, but on my machine under this particular test Go wins in both cases, and tinygo is doing so at about the same speed as C itself.
I'm not familiar enough with the internals to say for sure, but I do know Python has a penchant for dicts. Perhaps it looks up the function each time, whereas Go can be made aware of the function at compile time? That wouldn't be without cost.
Part and parcel with its love for dicts, Python data structures tend to not be shaped like C typically expects. Whereas Go data structures are, at most, lightweight wrappers around C-style structures, and are often even directly equivalent, making passing data about as simple as passing a pointer. Python may be getting bogged down in some kind of marshalling operation. That isn't cost-free either.
Which Python and which Go? There are so many different implementations and different versions of those implementations that this broad statement is meaningless.
From what I have installed on my machine, CPython 3.11.6 seems to take around 80ns to call a C function, gc 1.22.0 takes around 50ns to call the same C function, and tinygo 0.32.0 only takes around 1ns!
Such benchmarking is always fraught with problems, so your milage may vary, but on my machine under this particular test Go wins in both cases, and tinygo is doing so at about the same speed as C itself.