5/6/2023 0 Comments Java itimer(You might be wondering about the mysterious ITimer timer object above. On the same system used for the first experiment, this results in: duration = 5.678 ms + format.format (timer.getDuration ()) + " ms") Thread.currentThread ().sleep (0, 500) offered by other Java time-related methods: Uncomment various lines below to see the resolution Create an ITimer using the Factory class:įinal ITimer timer = TimerFactory.newTimer () įinal Object lock = new Object () // used by monitor.wait() below Public static void main (String args) throws Exceptionįinal DecimalFormat format = new DecimalFormat () Unfortunately, these are not good alternatives either, as the following code demonstrates: Occasionally, you can find alternative suggestions based on Object.wait(long) or Thread.sleep(long) methods. If you cannot loop over code being profiled a sufficient number of times to get the cumulative execution time in this range, you need another approach. On the system used above, System.currentTimeMilllis() is suitable only for profiling relatively long-lasting (100 ms and longer) operations. You should see now that this is naive at best. Java developer forums are full of arguments about whether a particular language trick offers performance advantages, with developers presenting "proofs" based on System.currentTimeMilllis() returning "0 ms versus 10 ms" for some new way of implementing a particular code paradigm. In most cases, the actual resolution has nothing to do with the fact that System.currenTimeMillis()'s return value is current time in milliseconds. Java developers on Linux enjoy 1-millisecond (ms) resolution, while Windows 98 users suffer with 50-ms resolution. You will discover that results vary based on your platform. When run in JDK 1.4.1 on a Windows 2000 system, produces the following: delta = 10 ms ("delta = " + (time - time_prev) + " ms") Long time = System.currentTimeMillis (), time_prev = time For (int r = 0 r < 3000 ++ r) System.currentTimeMillis ()
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