I remember there was a time I was very happy because H2D2 was running my Mandelbrot test program in about 650 milliseconds (whereas the original proof of concept, DALIS, took nearly 12 seconds to do the same thing).
Since moving over to my new MacBook and compiling the H2D2 source using Xcode, just look at the result now:
Whoa! 72 milliseconds! Now that's impressive. This new MacBook is pretty fast, but I'm sure the Apple LLVM compiler is also playing its part in achieving that level of speed. I have done some optimisation work in H2D2 recently, but I don't think I can take the credit this time.
It really pays to do this type of 'system level' programming in C (plus I enjoy it of course). Right, I'm off to work on parsing string expressions now...