wall time n. (also `wall clock time') 1. `Real world'
time (what the clock on the wall shows), as opposed to the system
clock's idea of time. 2. The real running time of a program, as
opposed to the number of {tick}s required to execute it (on a
timesharing system these always differ, as no one program gets all
the ticks, and on multiprocessor systems with good thread support
one may get more processor time than real time).