Comment by jerf

I like to characterize it as "the slowest language of the fastest class of languages". In general other compiled languages are faster, though generally we're talking 2 or 3 times at the most (Go doesn't optimize very hard but the language defaulting to unboxed values made up for a substantial proportion of that versus more box-heavy compiled languages), but Go is "generally" faster than nearly all non-compiled languages. "Generally" here means "on general code"; JIT languages can definitely outdo Go on heavily numeric code, even in scripting languages, because JITs are very good at that, but the sort of "general" code that isn't obviously numeric will be faster in Go than any non-compiled language.

This sort of complicated analysis doubles as another example of the difficulty of context-free "fast" and "slow" labels. Is Go "fast"? For a general programming language, yes, though not the fastest. If you reserve "fast" for C/C++/Rust, then no it is not fast. Is it fast compared to Python, though? Yes, it'll knock your socks off if you're a Python programmer even with just a single thread, let alone what you can do if you can get some useful parallel processing going.