RFR (XXS): 8143220: Fix documentation of InitiatingHeapOccupancyPercent
Jon Masamitsu
jon.masamitsu at oracle.com
Fri Feb 5 21:26:37 UTC 2016
Thomas,
I would leave out the part about InitiatingHeapOccupancyPercent being
used as
the initial value for IHOP because not enough data has been gathered to
make a
better estimate. While true today it may change and I don't think it is
needed as
part of the description. Explaining what happens when it is 100 would
be good.
I added the explanation about fragmentation (is it correct) because I
thought
that it would come up sooner or later but you can drop it, if you think
it is
too much. So I would suggest.
Percentage of the old generation heap occupancy (IHOP) after which a
concurrent
GC cycle is started at the end of the next garbage collection pause.
If adaptive IHOP is not being used (-XX:-G1UseAdaptiveIHOP), the IHOP is
fixed at
this value of InitiatingHeapOccupancyPercent. If adaptive IHOP is being
used,
InitiatingHeapOccupancyPercent is the starting value for IHOP. A value
of 0 causes
the concurrent GC cycle to run as much as possible. A value of 100
causes the
concurrent GC cycle to be delayed until the the old generation is
completely full.
Fragmentation waste in the old generation is not considered to be free
space.
InitiatingHeapOccupancyPercent is being used by G1.
Jon
On 2/5/2016 2:52 AM, Thomas Schatzl wrote:
> Hi all,
>
> can I have reviews for this change to the documentation of the
> InitiatingHeapOccupancyPercent global? I think due to recent changes
> to the behavior it is warranted that the (internal) documentation
> reflects it.
>
> Other suggestions for the text welcome.
>
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8143220
> Webrev:
> http://cr.openjdk.java.net/~tschatzl/8143220/webrev/
> Testing:
> local compilation
>
> Thanks,
> Thomas
>
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