Looking closer at the benchmarks, it seems that C# benchmark is not using AOT, so Go and even Java GraalVM get here an unfair advantage (when looking at the non SIMD versions). There is a non trivial startup time for JIT.
Sorry, I can't seem to edit my answer anymore, but I was mistaken, C# version is using AOT. But the are other significant differences here:
> var rounds = int.Parse(File.ReadAllText("rounds.txt"));
> var pi = 1.0D;
> var x = 1.0D;
> for (var i = 2; i < rounds + 2; i++) {
> x = -x;
> pi += x / (2 \* i - 1);
> }
> pi \*= 4;
> Console.WriteLine(pi);
For example, if we change the type of 'rounds' variable here from int to double (like it is also in Go version), the code runs significantly faster on my machine.
Try that on ARM64 and the result will be the opposite :)
On M4 Max, Go takes 0.982s to run while C# (non-SIMD) and F# are ~0.51s. Changing it to be closer to Go makes the performance worse in a similar manner.
