[cma]

I'd like to see a comparison of calling a dynamically linked function call vs a non-dynamically linked virtual call.

Dynamic linking has more indirection than you might expect because the function addresses can't always just be put at the call site during the library load (the places where you would want to write the address can be in code that is read-only mmapped to aid in sharing memory between processes and to avoid loading unused stuff from disk).

[zwieback]

In an ideal world the OS could still replace the call sites with straight calls to the loaded library, circumventing a jump table altogether. I don't remember what this is called, maybe something like a thunk, but I've seen it happen in the debugger where the first call causes a fault which rewrites the call site with the target address and subsequent calls are straight to the lib. This can work even if the chunk of code containing the call sites is shared and readonly, as long as the OS can override that.

[pmjordan]

The calls into jump tables are generally static, so the jump table itself can be prefetched. The jump table code is then a regular function pointer call, which is also monomorphic and so can be reliably predicted. I'd expect the impact to be small compared to a regular monomorphic function pointer call.