RFR: 8223498: Add Sum of Duration to the jfr summary command

[Erik Gahlin]

I don't see a benefit of adding a sum of duration column.

Events have thresholds. For example, the jdk.JavaMonitorWait event is 
only recorded if the event exceeds 20 ms so the sum would not be the 
actual sum. Also, things often happen in multiple threads which makes it 
hard to know what the value actually means.

The 'jfr' tool tries to not exceed 80 characters (to avoid wrapping), 
which is hard if another column is added. This especially true if user 
defined events are added with a longer namespace than "jdk."

The longer term plan is to add a more advanced command where users can 
aggregate data on arbitrary field and not just the sum as an aggregate 
function. Users would then be able to aggregate duration per event type, 
if they really wanted it.

Erik

> Hi,
>
> Could you review this enhancement, please?
>
> This enhancement adds the total duration of each event to the jfr 
> summary command to help the user determine which events to display in 
> the jfr output.
>
> webrev:
> http://cr.openjdk.java.net/~cito/JDK-8223498/webrev.00/ 
> <http://cr.openjdk.java.net/%7Ecito/JDK-8223498/webrev.00/>
>
> jbs:
> https://bugs.openjdk.java.net/browse/JDK-8223498
>
> I have passed the tests in test/jdk/jdk/jfr.
>
> Best regards,
> Chihiro