Integrated: 8255984: Shenandoah: "adaptive" heuristic is prone to missing load spikes

[earthling-amzn]

On Fri, 6 Nov 2020 20:00:25 GMT, earthling-amzn <github.com+71722661+earthling-amzn at openjdk.org> wrote:

> This change adds a "reactive" heuristic for triggering concurrent GC cycles.
> 
> The reactive heuristic maintains a margin of error and an allocation spike detection mechanism to trigger cycles somewhat more aggressively than the 'adaptive' heuristic. This heuristic 'reacts' to the outcome of GC cycles by adjusting the sensitivity of the triggers.
> 
> JBS ticket is here: https://bugs.openjdk.java.net/browse/JDK-8255984
> 
> The "adaptive" heuristic remains the default.
> 
> Steps to reproduce and test will follow shortly (there are no new jtreg test failures for Shenandoah with this change).

This pull request has now been integrated.

Changeset: aac5c2a8
Author:    William Kemper <kemperw at amazon.com>
Committer: Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/aac5c2a8
Stats:     348 lines in 13 files changed: 314 ins; 9 del; 25 mod

8255984: Shenandoah: "adaptive" heuristic is prone to missing load spikes

Reviewed-by: shade

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PR: https://git.openjdk.java.net/jdk/pull/1099