[psykotic]

> But doesn't the dynamic linker still have to do extra work to resolve the relocations in the executable, even when the dependency libraries are already loaded?

For dynamic linking there's usually only a single reference that needs to be fixed up in the PLT or GOT for each referenced symbol and the fix-ups are all localized, so that part is typically a very small cost. But this means every call to a dynamically linked library goes through an extra stub function, which adds I$ and BTB pressure compared to static linking.

(If you do things manually with dlsym there's also an extra indirection but it's a little different mechanically since you do an indirect call of a function pointer rather than doing a direct call to a forwarding stub. The advantage of the forwarding stub is that even if there's a BTB miss for either of the two direct calls, you don't suffer a branch mispredict but just a few front-end cycles waiting for the instruction decode, which VTune labels as a "branch resteer". The direct call option also leads to smaller code size for each call site which helps with I$ pressure. Basically it's the difference between CALL rel32 and MOV tmp, [RIP + disp32]; CALL [tmp].)