Yesterday I ran into smallpt, a tiny raytracer in 100LOC in C++.
It turns out it works as a nice cross-lang CPU benchmark! So I ported it to crystal and ran some benchmarks comparing with other implementations and … well, the result is README.md
Tl;DR: crystal gives you readable code with practically the same performance as C++ (as expected) and multithreaded performance scales linearly (this is an ideal workload TBH)