[capableweb]

What libraries like this could you really extract "performance/$" from? Sounds like a mostly financial metric.

It's so situational that you cannot say outright exactly how much something cost in different scenarios. Doing so requires strict metrics about other things at the same time, and could only be done as an analysis of what happened, not what will happen in the future. Subtle bugs and things like just using a different data structure would impact the performance, down to the tiniest detail.

If you're so adamant to see metrics, you could use TechEmpower's framework tests, latest one placing 5th Actix in the "Composite score" (https://www.techempower.com/benchmarks/#section=data-r20&hw=...), as a result of being pretty high up in the specific benchmarks. But even with that information, it doesn't mean it'll be the 5th fastest framework when you use it.

I guess the point is: do you own benchmarks for the specific areas where you need it to be fast, calculate what your costs would be for hosting it, and you'll have your "performance/$".