Consecutive Full GCs but no OOM

[Shawn Heisey]

On 5/14/2018 11:41 AM, Thomas Schatzl wrote:
> However not only gc overhead is accounted for in the decision to give
> an OOME, but also how much memory the full gcs free.
> 
> Probably the most important flag here would be GCHeapFreeLimit:
> simplified, if free space after full gc is below this percentage of
> total heap, that full gc does not count against GCOverHeadLimit.
> 
> Looking at the log output, after Full GC there is ~4% of max heap
> available. The default value for GCOverHeadLimit is 2 (percent).

I have a question sparked by this discussion, but it's only indirectly
related.

How long a timeframe is examined to determine whether the 98% and 2%
thresholds are violated?  This information is not in the documentation
that I've been able to find.  Here's an example of a java 8
documentation link where that information is not shown:

https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/cms.html#sthref35

Thanks,
Shawn