What do the terms CPU-time Wall-clock-time mean?
Some documentation (programming) refers to these terms when there is some kind of limitation on CPU usage, for example:
Background tasks are limited by the amount of time using the wall-clock .
background tasks are limited to 30 seconds of use of the wall-clock.
Without understanding what exactly these terms mean it becomes difficult to adapt a software to even do not extrapolate the recommended CPU usage.
1 answers
CPU Time is the time the processor spends to perform a task.
Wall Clock Time is all the time spent to execute a task, so if there are interruptions in the execution of the activity the wall clock does not stop counting, but the CPU time is not considered.
The outage may occur because the processor divides its usage with other threads or because it needs to wait for a device external to the CPU to respond or the algorithm is on hold without executing Nothing.
This is a way to differentiate whether the limit you can use uses one criterion or another. If the limit was on the CPU time in fact it could run for minutes, hours or even days, as long as most of the time it is not running anything.