Java Wall Clock Time Vs Cpu Time

This is the time that your code actually spends executing code on the cpu.

Java wall clock time vs cpu time.

The netbeans default is to use wall clock absolute time for all method timing calculations. Cpu time is time spent in the cpu doing actual work as opposed to waiting or not being scheduled. Sys time is the amount of cpu time spent in the kernel. Cpu time is the total execution time or runtime for which the cpu was dedicated to a process.

Elapsed real time real time wall clock time or wall time is the actual time taken from the start of a computer program to the end. The other type of time that we re interested in measuring is wallclock time. This is basically the time that you see in the clock. If this is a single threaded process.

The process spent all of its time using the cpu. Wall time is thus different from cpu time which measures only the time during which the processor is actively working on a certain task. The wall clock time is 9 seconds. If cpu time is desired it can be enabled from the advanced settings area in the attach profiler window.

It s easier to express the possible relationship as a ratio of cpu time wall clock time which is to say cpu second. The first is cpu time. Real time is the total elapsed time of the gc event. A faster cpu will likely make the program run faster.

This means executing cpu time spent in system calls within the kernel as opposed to library. The option is called use thread cpu timer solaris only. Each of those small task slices is counted toward the total execution time. User time is the cpu time spent in user mode code outside the kernel.

The cpu must service many processes every second not just yours so your process only gets small task slices in between processing other requests. Scea part 1 part 2 3 core spring 3 togaf part 1 and part 2. In the example above cpu time was lower than wall clock time but other relationships are possible. A cpu time approach is available but currently only on solaris.

The cpu time spent is 8 seconds 5 seconds for cpu 1 and 2 seconds followed by 1 second for cpu 2. Cpu time is not wall time as in a clock on the wall. Wallclock time is the total time between starting an operation and it completing. In other words it is the difference between the time at which a task finishes and the time at which the task started.

Wall clock time cpu time unless you have multiple cpus.