CRR (S/M): 7075646: G1: fix inconsistencies in the monitoring data
tony.printezis at oracle.com
Fri Aug 12 08:20:12 PDT 2011
Thanks to Jon Masa for several good suggestions, here's the updated webrev:
Tony Printezis wrote:
> Hi all,
> I would like a couple of code reviews for some fixes in the G1
> monitoring code:
> The main motivation behind these changes is that G1's jstat output has
> inconsistencies and has been causing a few test failures. Here's a
> quick summary of the changes:
> - Reworked the way the capacities of the various spaces are calculated
> so that only the eden space used counter needs to be updated when a
> new eden region is allocated.
> - Now the values of the various sizes that need to be reported are
> calculated synchronously in all the appropriate places in the code and
> stored so that they do not need to be recalculated every time they are
> - The jstat counters for the young / old gen capacity are now
> correctly updated.
> - We ensure that when we are reporting a capacity to jstat we
> artficially pad it so that it's never 0 (as jstat does not handle 0
> capacities gracefully).
> I attached a file that has before / after output comparisons, along
> with some commentary, for the various jstat GC parameters.
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