Which, I think, misses the point. Unless your Go program is currently not fast enough, why would you consider a port? And, if it isn't fast enough, are you sure you are using the appropriate algorithms and tools for the job? It may be that Go isn't the right language, but I would think long and hard before a re-write from any language to any language, unless it's a toy project (in size, not importance), in which case, you could rewrite it and find out in a day or two and it might be a fun experiment worth writing about.

And, lots of benchmarks between C and Go have already been done. Likewise, Rust and Go, and Rust and C.