Comment by mst

> HVM2 is finally a correct algorithm that scales.

This, I think, is the key thing people are missing.

Maybe your low level performance will never be as good as hoped, but for this sort of task, "the parallelisation part works and produces correct results" might not be sufficient but is absolutely necessary, and any optimisation work done before that has such a high probability of having to be thrown away that under similar circumstances I wouldn't bother in advance either.