Comment by mjevans
The real world benchmark is measuring it from invocation, both for cold launches and 'hot' (data cached from the last run).
Interestingly I might have only ever used the time (shell) builtin command. GNU's time measuring command prints a bunch of other performance stats as well.
I'm annoyed every time I have to write $(which time). But the stats given by -v are just so much more valuable from gnu-time.