RFR (S/M): 8136678: Implement adaptive sizing algorithm for IHOP
thomas.schatzl at oracle.com
Fri Nov 6 10:42:31 UTC 2015
after Sangheon's recent comment about potential division by zero, I
went through this change and also fixed this here.
Also, the output printed the wrong numbers (i.e.
_allocation_rate_s.last() vs. _allocation_rate_s.oldest()).
On Thu, 2015-11-05 at 10:54 +0100, Thomas Schatzl wrote:
> Hi all,
> can I have reviews for this change that adds a G1IHOPControl instance
> that adaptively adjusts the current IHOP based on allocation rate and
> marking cycle length?
> Instead of statically setting the IHOP value (by the user at VM
> startup), this change adds adaptive IHOP control similar to CMS.
> The main change is in G1IHOPControl lines 106-121, the rest is just
> setup changes and a unit test.
> This feature, enabled by setting G1UseAdaptiveIHOP, is disabled by
> default for now. It is planned to be enabled by default in JDK-8136680,
> when more thorough testing has been conducted by SQE.
> Generally it boosts G1 throughput significantly due to the low IHOP
> default value of 45, which with that change typically gets >70, if not
> up to 80-90, decreasing pause times significantly.
> It depends on JDK-8136681 which is also out for review.
> jprt, vm.gc with G1UseAdaptiveIHOP disabled and enabled, unit test
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