There are limitations in sharing text segments in different processes, and extra memory usage mapping in text segments so relocations can be, uh, relocated, but once running there is no additional performance overhead. The runtime image is effectively "self-modified code" by the OS loader, patched to final addresses. No PIC register, no indirect references.
Right. You've described the performance impact: a ton of relocations hurts startup time, and the modified memory reduces sharing, costing additional memory. If startup time does not matter and memory is free, sure, it has no costs.
