That does not show it's 10% slower on average; it shows that C++ is 0.9917938291x as fast as Rust. They both have some where they win by 30%, most are closer, Rust is just faster on average.
> But they use llvm instead of gcc for c++,
C++ g++ g++ (Ubuntu 9.2.1-9ubuntu2) 9.2.1 20191008
?
> gcc is in average 20% faster than clang.
Extremely citation needed.
What kind-of time measurements? What kind-of average?
This chart shows some time measurements:
https://benchmarksgame-team.pages.debian.net/benchmarksgame/...
:and the geometric mean is faster for the C++ programs, but the median seems faster for the rust programs.
Statistical artifacts?
I interpreted the parent to mean a simple average, so I did exactly that: calculated the percentage for each, and averaged them. In the colloquial term, "mean".
If that claim was true …
> gcc is in average 20% faster than clang
and if that claim was true …
then we might guess the rust programs average could be 10% faster than the C++ programs average, if both used the same compiler backend
— because those rust programs were compiled with llvm but those c++ programs were compiled with gcc.
But they use llvm instead of gcc for c++, and gcc is in average 20% faster than clang. Therefore, rust is 30% slower, at least on heavily optimised programs.
And hyper is not the fastest http server, but the actix one is one of the fastest yes.