[ad_1]
CPU time is the time taken by the processor to complete a task, measured in time, percentage of processor capacity or clock ticks. Elapsed time is the total time taken for a process from start to finish, including input/output and other interactions. Multi-core processors make CPU time more complicated as it can be split across multiple processors.
A computer’s central processing unit (CPU) is where most of the low-level computation takes place. CPU time is the amount of time it takes for the CPU to do its part of the process. This period is part of elapsed time, a figure that includes CPU usage, input and output time, and other computer interactions. Elapsed time covers the entire execution of a program from start to finish. CPU time used to be a fairly simple calculation, but with the advent of multi-core processors it has become more complicated.
CPU time measures the time it takes to complete an operation from the perspective of the processor. Regardless of how long it takes for the entire operation to execute, CPU time only measures from the point where it reaches the processor until it finishes with the processor. It is typically measured as time, a percentage of processor capacity, or in clock ticks.
Typically, real-time CPU time measurement is only used when people need to tell the time. Other computers and programs generally find the other methods of determining time more useful. Since most computers don’t think in conventional time, many programs that produce time measurements in a real-time quantity use one of the other methods and convert those results.
CPU time is expressed as a percentage of capacity when overall processor utilization is the goal. This is another method of displaying information for a human audience. This method is mainly used to find the total load on a CPU. These figures are used to find peak and idle times on servers or simply monitor personal computer performance.
Clock ticks are the hardest method of measuring CPU time for humans to follow, but are typically the most useful for other computer programs. Clock ticks are a variable amount of time affected by processor speed. The faster the processor, the faster the clock ticks. These ticks are monitored by other programs to space processor usage and prevent bottlenecks.
Elapsed time, also known as wall clock time or real time, is the entire time it takes to run a process from start to finish. With elapsed time, the process is measured from when it starts, regardless of its point of origin, to when it ends. This time can involve anything from mouse clicks to CPU processing or disk access time. Until the advent of multi-core processors, elapsed time was always equal to or greater than CPU time.
Multi-core processors give CPU time a twist. When using multiple cores, CPU time is the total time spent on each processor. Because they can receive a single command and split it across multiple processors, it is possible for the total time used to be greater than the total time for the process to run.
