Wall-clock time, or wall time is a duration that measure the time from the start to the completion of a task.
- elapsed real time
- real time
- elapsed time
Wall-clock time is the time that a clock on the wall (or a stopwatch in hand) would measure as having elapsed between the start of the process and “now”.
Elapsed time may be negative due to:
- leap second for instance if your process goes in millisecond
- change in the OS clock if your function doesn't return a monotic time.
When using a non-monotonic clock source is to always check whether the elapsed time is negative.
In the context of a task being performed on a computer, wall-clock time is a measure of the real time that elapses from start to end, including:
- time that passes due to programmed (artificial) delays
- or waiting for resources to become available.
Wall-clock_time is is the difference between the time at which a task finishes and the time at which the task started.