wall time definition
(Or "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 ticks
required to execute it (on a time-sharing
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).