Is Duration Cpu Time Or Wall Clock Java

This clock rather than systemdefaultzone should be used when you need the current instant without the date or time.

Is duration cpu time or wall clock java.

Often it is useful to measure cpu. The difference in wall and cpu time is rather large for this task clocking in at 35 237 seconds which was time sliced out to other processes. The reason being is because of the time it takes to print over 50 000 files to the screen therefore the linux kernel s scheduler was free to give more time slices to other processes. However the result may and will be inaccurate as system currenttimemillis measures wall clock time.

I ve always understood clock time to mean an instant not a duration. Execution time in nanoseconds. The cpu time is measured in clock ticks or seconds. Java8 stopwatch 100000000 6 666667e 11 0 5820 seconds 6 666667e 11 8 4530 seconds the code stopwatch data type is for measuring the time that.

The current date and time depend on the time zone and for globalized applications a time provider is necessary to ensure that the date and time are created with the correct time zone. Wall clock time is elapsed time the time on the clock on the wall. This clock is based on the best available system clock. System currenttimemillis java system class also provides the static method currenttimemillis that returns the difference between the current time and midnight january 1 1970 utc in milliseconds.

Now you maybe wondering why cpu time and wallclock time aren t the same number. Obtains a clock that returns the current instant using the best available system clock converting to date and time using the utc time zone. 5000372657 execution time in milliseconds. Changing the system time can affect the results or a leap second will disrupt the result.

After all your java process doesn t to have to wait in line at starbucks. Javac stopwatch java execution. Wall clock time may change for many reasons e g. None a utility class to measure the running time wall clock of a program.

Time elapsed is the difference between these two values. Clock was added in java 8 and provides access to an instant in time using the best available system clock and to be used as a time provider which can be effectively stubbed for testing purposes. Wall clock time cpu time unless you have multiple cpus ok well wall clock time in that context is new to me and on most charge reports i ve seen it was called elapse time. Ideally currenttimemillis should be used to measure wall clock time.

Java stopwatch n dependencies.