Not that I think those metrics are all that relevant, but can someone explain to me how just-js ranks so highly? Very much defying my expectations in comparison with some of the top representatives of compiled languages.
Pretty much every set of benchmarks out there is ruined by monstrous unrealistic code that squeezes out 5% more performance than actually well written code.
As a side note, one flaw of TechEmpower benchmarks is that to my knowledge they use the original "wrk" tool, which only supports HTTP 1.0 and is sensitive to "coordinated omission" [0]. This means it ends up being biased in favor of web frameworks that implement specific optimizations or have specific behaviors that aren't actually useful in a production context.
Or is it some Goldilocks not-unoptimised not-too-optimised I'll-know-it-when-I-see-it wishful-thinking thing?
Apparently async db requests and batching transactions are the key to winning on that benchmark: https://news.ycombinator.com/item?id=24315512
I wish more benchmarks would produce latency vs requests/second curves in microseconds. I bet the latency is massive due to batching.
You read see the source of the tests here: https://github.com/TechEmpower/FrameworkBenchmarks/tree/mast...
The SQL code seems quite optimized (manually compiling database packets instead of using a library). Most code seems quite static and very small, so it's probably very quick. I don't think you can actually use the framework like that in practice, though.
Additionally a lot of these benchmarks focus on things that the JS engines are very good at. It isnt like they are running CPU intensive tasks in JS.