So when I talk about language performance, I focus on developer performance. Hardware is cheap, developers are expensive (and good ones hard to get), and frankly all the system’s I have worked on for the last decade were more I/O bound than CPU bound (I stress the word “I” because this is where I work and my experience, YMMV).
I get it that Google wants to squeeze every last drop out of their CPUs, but even the largest site I’ve worked on (1.5b pages per month) consisted of code mostly waiting for the database or the search engine and we only ever had one subsystem that was performance-critical (15k transactions per second with little room for parallelism).
To me, run-time performance is table stakes - granted, an interpreter is often too slow, but every decent VM I’ve looked at is sufficient, including BEAM. Make developers faster, not your code. That’s why I want metaprogramming facilities and bells’n’whistles like that- they let you focus on developer productivity, not on coding for the machine. Code is for humans. Running it in production is mostly a side-effect