Thanks Bernd, See below.
> A 10ms sleep is problematic as a test case since some OS only allow Worse > Timer Resolution (for some like Windows it even depends on which timer is > currently active, the default timer uses 15,6ms which is only changed in > latest Windows 10 I think). So the variation you see is more likely caused by > the delay you use and less likely caused by System.nanoTime (as used by > Stopwatch). Interesting. Not sure about that though because I log the System.currentTimeMillis around the sleep and the diff is always 10 or more never less. > For your test (not sure how valuable that is) I would go with 100ms sleep and > allow 85-115ms stopwatch results. I’ll give that a try. Thanks again, Erwin. > > > -- > http://bernd.eckenfels.net > > ________________________________ > Von: Erwin Hogeweg <erwin.hoge...@me.com.invalid> > Gesendet: Freitag, Juni 7, 2019 2:21 PM > An: Commons Users List > Betreff: Re: org.apache.commons.lang3.time.StopWatch resolution > > Thanks for the replies and the links gents. Still confused. I can understand > that you can’t expect nanosecond resolution but the diff I noticed is 1-6 > ms... on a 10 ms interval. Those are eternities in modern day CPUs. > > I am planning to use the stopwatch with a second resolution so this test is > kinda irrelevant but I am still surprised by the result. I might take a look > at the implementation later to get a better understanding. > > Thanks again for the help. > > > Erwin > > El jun. 6, 2019, a la(s) 22:41, Remko Popma <remko.po...@gmail.com> escribió: > >> Timers and elapsed time in Java is an interesting topic. Can be a moving >> target though... >> >> Some recent articles: >> https://hazelcast.com/blog/locksupport-parknanos-under-the-hood-and-the-curious-case-of-parking/ >> >> https://hazelcast.com/blog/locksupport-parknanos-under-the-hood-and-the-curious-case-of-parking-part-ii-windows/ >> >> Remko. >> >> (Shameless plug) Every java main() method deserves http://picocli.info >> >>> On Jun 7, 2019, at 6:13, Gary Gregory <garydgreg...@gmail.com> wrote: >>> >>> The OS' clock resolution is in play here, which depending on your OS will >>> give you varying results. Also, on Java 9, you get better clock resolution >>> for certain APIs. Kinda messy... >>> >>> Gary >>> >>> On Thu, Jun 6, 2019 at 4:28 PM Erwin Hogeweg <erwin.hoge...@me.com.invalid> >>> wrote: >>> >>>> Hi, >>>> >>>> I am tad confused about the StopWatch resolution. I have a very basic >>>> JUnit test that starts a stopwatch, wait for 10ms and then stops it, and >>>> checks the value. In about 40% of the cases it is less than the 10ms wait >>>> time. >>>> >>>> Is that expected? What is my blind spot? >>>> >>>> >>>> Regards, >>>> >>>> Erwin >>>> --------------------------------------------------------------------- >>>> To unsubscribe, e-mail: user-unsubscr...@commons.apache.org >>>> For additional commands, e-mail: user-h...@commons.apache.org >>>> >>>> > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-unsubscr...@commons.apache.org > For additional commands, e-mail: user-h...@commons.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org
