RFR JDK-8060017 G1: Report heap sizing time

[Thomas Schatzl]

Hi Eric,

On Tue, 2015-10-13 at 15:35 -0400, Eric Caspole wrote:
> Thanks Mikael!
> 
> I still need one more review, anyone?
> Thanks,
> Eric
>
> On 10/13/2015 06:02 AM, Mikael Gerdin wrote:
> > Hi Eric,
> >
> > On 2015-10-12 15:35, Eric Caspole wrote:
> >> Hi Mikael,
> >> I've returned the expand time as an out parameter in this new webrev:
> >>
> >>   http://cr.openjdk.java.net/~ecaspole/JDK-8060017/06/webrev/
> >>
> >> Let me know what you think.

some comments:
 - the change only covers gathering timing numbers for expansion at the
end of GC. Expansion may also occur during GC when the space used for
evacuation is not sufficient any more.
Not sure if that is intended, but the CR itself does not indicate that.

If you think gathering information about time to expand during gc is out
of scope of this CR (that's fine, it was me who suggested that), please
consider adapting the CR and create a new one for tracking the expansion
time during Object Copy.

 - please add the verification for this log message to the
TestGCLogMessages test.

 - maybe a better name for this phase that indicates that it is only
about expansion at the end of the GC could be found?

 - I do not think it is a good idea to record heap expansion time during
full GC. The PhaseTimes data structure is otherwise only filled in
during young gc, so it's just confusing. (In G1CollectedHeap::
resize_if_necessary_after_full_collection()).

Thanks,
  Thomas