[RFR] 8043766: CMM Testing: 8u40 Decommit auxiliary data structures

[Thomas Schatzl]

Hi,

On Fri, 2014-09-26 at 15:01 +0400, Andrey Zakharov wrote:
> On 26.09.2014 14:47, Thomas Schatzl wrote:
> > G1ConcRSLogCacheSize of 10 does not require that much memory (and in
> > fact is default) so that you need to worry about its maximum size.
> >> I'm worried about 2^23 - 2^30 caches size which can brings massive
> >> swapping and timeouts of tests
> > Then I suggest just removing the ...Data25/Data30, even ...Data20,
> > tests. There is not much difference in behavior from a GC point of view
> > between these heap sizes. The values are simply used to size that data
> > structure.
> >>> - fixing G1ConcRSLogCacheSize would also remove the need to calculate
> >>> some maximum value for G1ConcRSLogCacheSize. GetMaxCacheSize()
> >>> calculates the maximum G1ConcRSLogCacheSize based on the free java heap.
> >>> However, the data structure is allocated on the C heap, there is no real
> >>> connection between free java heap and free C heap anyway.
> >> Could please, suggest something here?
> >> I'm just judging about available memory by available heap memory.
> >> Thanks.
> > Available Java heap memory (Runtime.freeMemory() returns the available
> > memory on the Java heap), not available C heap memory. One has no direct
> > connection to the other.
> >
> > By simply removing the tests with the large G1ConcRSLogCacheSize values,
> > which imo do not add a lot, you do not need such a contrived check.
> As we have this feature in product - there needs to be tested.

:) Well, I would prefer to do the test whether G1 supports higher
G1ConcRSLogCacheSize values in a different test/CR, but feel free to
keep it.

Reviewed.

Thanks,
  Thomas