While I can agree we don’t have sufficient data to make hard conclusions on this front, I think there are enough early indications that point to Rust being able to stay on par with or even outperform C++ in this regard:

I'm skeptical of these claims, not because X or Y is better or worse, but because milking the last drop of performance has far more to do with software architecture than it has to do with the programming language per se.

Also, I think this sort of argument always leads to specious reasoning. C is the undisputed performance lead, and you surely do not see Rust proponents using benchmarks to argue they should rewrite all Rust code in C.