Mach_absolute_time

Question

In the performance section of the Cocoa documentation, specifically in "Gathering Launch Time Metrics", they suggest using explicit timestamps using machabsolutetime, then finding the time difference and using that as a way to judge algorithm performance. Unfortunately, while this would be great, and an invaluable tool for optimizing code, they never actually say how you are supposed to use said function, nor what needs to be included in order for it to work. Since I've never worked with kernel functions before, I have no clue where to start, and though I've fooled around with it extensively, I have yet to get it to work, or even to figure out the function parameters or what value type it returns.
If someone could explain its proper usage, that would be great.
Thx,
Haplo

Answer 1

Well, that was helpful, and now I can apparently get the absolute time units, however it says nothing about displaying the results. I've tried doing this by NSNotify(), however it usually prints 0, even after measuring the time it takes to count from 0 to 1 million. Oddly enough, 0 to 1 billion returned a value of 2 (trying int and unsigned int). Considering that I believe I've estimated it to take 7.8 or so seconds to do the billion incriment (no optimizations), a return of 2 does not make sense for a nanosecond or finer resolution of time.