RFR: 8253646: ZGC: Avoid overhead of sorting ZStatIterableValues on bootstrap

[Claes Redestad]

On Mon, 28 Sep 2020 13:33:39 GMT, Erik Österlund <eosterlund at openjdk.org> wrote:

>> - Defer sorting to when starting the ZStat thread
>> - Improve the sorting logic to avoid unnecessary strcmps
>> - Only sort those ZStat objects that actually needs to be sorted
>> 
>> This reduces bootstrap overhead due sorting from around 75k to around 29k instructions when ZStat service is started,
>> and removes it almost completely otherwise.
>
> Looks good.

Thanks for reviewing, @pliden and @fisk

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PR: https://git.openjdk.java.net/jdk/pull/373