AbsoluteTiming[expr] evaluates expr, returning a list of the absolute time that has elapsed, together with the result obtained.
AbsoluteTiming gives the absolute number of seconds of real time that have elapsed, multiplied by the symbol Second.
AbsoluteTiming has attribute HoldAll.
AbsoluteTiming[expr;] will give timing, Null.
First[AbsoluteTiming[expr;]] /. Second->1 yields just the number of seconds of time elapsed in the evaluation of expr.
AbsoluteTiming is always accurate down to a granularity of $TimeUnit seconds, but on many systems is much more accurate.
See Section 2.14.3.
See also: Timing, TimeConstrained, SessionTime, AbsoluteTime.
New in Version 5.0.