Which version was that with? GraalVM can JIT compile regular expressions these days, with the same compiler as everything else. They implemented TRegex on top of Truffle so regex can be inlined and optimized like regular code.

Performance does indeed depend on workload. There's a page that compares GraalPy vs CPython and Jython on the Python Performance Suite which aims to be "real world":

https://www.graalvm.org/latest/reference-manual/python/Perfo...

There the speedup is smaller, but this is partly because a lot of real world Python workloads these days spend all their time inside C or the GPU. Having a better implementation is still a good idea though, because it means more stuff can be done by researchers who don't know C++ well or at all. The point at which you're forced to get dedicated hackers involved to optimize gets pushed backwards if you can rely on a good JIT.