RFR: 8255984: Shenandoah: "adaptive" heuristic is prone to missing load spikes [v7]

[Aleksey Shipilev]

On Sun, 22 Nov 2020 10:02:13 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> earthling-amzn has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - Do not re-sample allocation rate with higher frequency
>>    
>>    This causes too many false positives and triggers unnecessary cycles.
>>  - Sample allocation rate even if cumulative bytes allocated hasn't changed
>>    
>>    Without this, the average allocation rate will be much higher than it should be.
>
> Okay, I have a minor suggestion that seems still preserve the semantics. It is generally looks good, the testing passes, and benchmarks look okay (some regressions, but expected). Feel free to integrate.

Congratulations! If you have time, please work on removing old alloc spike threshold and penalties handling.

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