RFR: 8232594: Make the output of the JFR command duration more user friendly

[Chihiro Ito]

Hi Erik,

I can't imagine one event lasting more than a day.
Therefore, I think the number of days is unnecessary.
I also think we don't need duration as detailed as ns.

So how about using 0.001 ms to hours?

Also, it would be difficult to see all the units displayed.
About rounding, how about using up to 3 units?

For example:
27 h 34 m 56 s
34 m 56 s 789 ms
56 s 789.012 ms
789.012 ms

Regards,
Chihiro


2019年10月30日(水) 2:57 Erik Gahlin <erik.gahlin at oracle.com>:

> Hi Chihiro,
>
> I don't think 1 day is a good representation of for example 27 hours.
> The precision is too low.  I also think numbers should be rounded up
> where applicable.
>
> When a duration is short, it is often convenient to use ms (with some
> fractions) instead of microseconds. It makes it easier to compare
> values. This is especially true if you are looking at multiple values
> and want to compare them, for example GC pause time.
>
> It is probably a good idea to first decide how values should be
> formatted before attempting an implementation.
>
> Erik
>
> > Hi,
> >
> > I tried to implement this to output an accurate time duration.
> > Could you review this, please?
> >
> > Is a rounded duration better than an exact duration?
> >
> > JBS https://bugs.openjdk.java.net/browse/JDK-8232594
> > webrev http://cr.openjdk.java.net/~cito/JDK-8232594/webrev.00/
> >
> > Regards,
> > Chihiro
>
>